Critique of 1945 German aircraft designs - where were the mistakes?

[Avimimus]

I heard rumour that TsAGI analysis found that the Ta-183 Design II would have shed its tail (although the IAe 33 Pulqui II seems to have eventually managed to make a somewhat similar t-tail work). What other issues did late war WWII designs have?

Ju EF 128 intakes might have had a lot of duct losses, the Gotha P.60 upper intake might have had issues with air-pressure fluctuations with variations in angle-of-attack, the later Messerschmidt P.1112 design intakes seem even more dubious... would any of these have worked adequately? It is interesting to think about.

With more than 75 years of hindsight - what other ideas can we rule out? Which aircraft might have gotten off the ground?

 

[Nik]

The end-game reminds me of the French pre-war chaos: Sundry wondrous designs, but totally out of lead-time, resources etc to resolve / de-bug / mass-produce...
whimsy:
France equipped with DeLannes and Payen Darts could have been a very nasty shock to the Blitzkrieg air-cover. Losing dozens of Stukas per sortie, having precious Me 109 and 110 crews culled, getting the Panzers' logistics strafed would have allowed time for some 'Joined-Up Thinking'...
/

 

[Michel Van]

How can i explaint this situation in 1945 simple ?
TOTAL CHAOS !
end 1944 the German industry collapsed
They were using presst particle board als replacement for Aluminum in Aircraft !
on the other side the German Aircraft industry spit fast our one Wunderwaffe after another

WHY ?
The NAZI gave order after order, in despair hope that one of those bring the final victory.
on other side suddenly allot engineers were involved in Wunderwaffen projects.
and can't be call in for deadly frontline duty
if that project was realistic or not they worked on it until capitulation of Third Reich
leading to stuff like Ta-183, Gotha P.60, Ju EF 128, Maus and other far fetch projects
it was literally life assurance for the engineers in 1944/45

 

[HoHun]

Hi,

it was literally life assurance for the engineers in 1944/45

Well, we had a discussion on that on a German forum, and it turned out that in July of 1944, the Jägerstab had all projects stopped that were not part of the official program. So any engineer working on a project not based on a Jägerstab or later Rüstungsstab requirement wouldn't have gained any protection from that ...

Reine Papierprojekte der deutschen Luftrüstung

Keine Ahnung, wie das administrativ ablief. Ich weiß nur, das der Uk-Antrag für jeden einzelnen Mitarbeiter von der Firma an die betreffende Dienstelle der Wehrmacht gesandt wurde und diese den Antrag genehmigte oder eben ablehnte. Meine konkreten Fälle betreffen auch nicht das Entwurfsbüro...

www.flugzeugforum.de

Here's an order to Blohm & Voss, requesting the development of a jet fighter with a He S 011 engine, based on 1) Blohm & Voss' Volkjäger design, 2) based on the designs Blohm & Voss had previously submitted for a high-performance piston-engined fighter, in the configuration of a flying wing with wingtip stabilizers:

Reine Papierprojekte der deutschen Luftrüstung

Keine Ahnung, wie das administrativ ablief. Ich weiß nur, das der Uk-Antrag für jeden einzelnen Mitarbeiter von der Firma an die betreffende Dienstelle der Wehrmacht gesandt wurde und diese den Antrag genehmigte oder eben ablehnte. Meine konkreten Fälle betreffen auch nicht das Entwurfsbüro...

www.flugzeugforum.de

Regards,

Henning (HoHun)

 

[Antonio]

would any of these have worked adequately?

Some concepts were actually tested or studied just after WWII, thus offering clues about its viability.

 

[red admiral]

Some concepts were actually tested or studied just after WWII, thus offering clues about its viability.

I think it's telling that the postwar aircraft that had most input from the German (or ex German) designers don't really seem to have been that successful, even when paired with more powerful and reliable engines. E.g. Pulqui II, XF-92

 

[paralay]

Countries that win wars postpone promising developments "for later". During the escalation, you need a lot of proven weapons, it brings victory

 

[Scott Kenny]

My critique of WW2 German aircraft designs is that they kept old designs in service long past their best-by date.

Me109? Designed in 1936. Should have been replaced by 1942 at the latest, 1941 would be better.
Fw190? Designed in 1939. Should have been replaced by 1944.

In comparison, the P-40 Warhawk was introduced in 1939, replaced by P-51 and P-47 in late 1943 and late 1942, respectively.

 

[_Del_]

My critique of WW2 German aircraft designs is that they kept old designs in service long past their best-by date.

To get a new design into service takes time and engineer-work. Even once it is essentially ready, after all the testing, it takes time to convert a factory, uninstall tooling, install the new stuff, train your line workers, etc. All that time is time you could be manufacturing airplanes that are considered "good enough".
Then once they start coming off the line you have to train aircrew, maintainers, build a logistics train, etc.
Unless a new design represented a substantial improvement, it's going to lose on the basis of opportunity cost.

 

[Antonio]

@Avimimus

The answer to your question comes from different factors which are being summarised in the precedent posts. You can find out more from the contents in the forum and then going to the books: Justo Miranda, Dan Sharp, Smith & Creek, Luftwaffe Secret Projects... for the German projects and Early post WWII secret projects from Tony Buttler (British/USA/Soviet), JC Carbonel (French) and also in minor countries where German designers were hired, to find how the III Reich tech was studied/tested/adopted or rejected according to their viability

 

[HoHun]

Hi Scott,

My critique of WW2 German aircraft designs is that they kept old designs in service long past their best-by date.

Me109? Designed in 1936. Should have been replaced by 1942 at the latest, 1941 would be better.
Fw190? Designed in 1939. Should have been replaced by 1944.

In comparison, the P-40 Warhawk was introduced in 1939, replaced by P-51 and P-47 in late 1943 and late 1942, respectively.

I'd argue that generally, it only pays off to replace a fighter aircraft with a better type if you have a new engine type available.

As we know thanks to Calum's "Secret Horsepower Race", the development of new engines took quite unexpectedly long in Germany (and not only in Germany).

The Fw 190 was, for a while, considered to be the Me 109 replacement, but as the BMW 801D required C3 fuel, which was a limited resource, this turned out not to be feasible. The Me 309 was planned as an Me 109 replacement, but the DB 603 wasn't ready, and wasn't powerful enough. The Fw 190 was to be replaced by the Ta 152 (though that really was more of an evolutionary development), but shortly after production started, it was stopped again because the Red Army overran the fuselage and wing production site at Posen.

The Me 262 was a new design with new engines, obviously, and the He 162 had a new engine in the BMW 003 as well, though it can be argued that it was untypical in having less powerful engines than the Me 262. (The He 162 wasn't really a replacement for the Me 262 though, and the Focke-Wulf approach to the Volksjäger tender showed that they considered the "new fighter - new engine" paradigm valid too, as their suggestion was a fighter suitable for the HeS 011 engine, but feasible as a BMW 003 aircraft for as long as the HeS 011 wasn't available.)

I believe there are few fighters internationally in WW2 that had successors powered by the same engine, though I can think of at least one example

Regards,

Henning (HoHun)

 

[Scott Kenny]

I'd argue that generally, it only pays off to replace a fighter aircraft with a better type if you have a new engine type available.

As we know thanks to Calum's "Secret Horsepower Race", the development of new engines took quite unexpectedly long in Germany (and not only in Germany).

Fair point.

Especially about the lack of 100octane Avgas.

I believe there are few fighters internationally in WW2 that had successors powered by the same engine, though I can think of at least one example

Pretty sure most of the USN aircraft all ended up on R2800s, even the Bearcat.

 

[HoHun]

Hi Scott,

Pretty sure most of the USN aircraft all ended up on R2800s, even the Bearcat.

Spot on, I was thinking the same

It's a rather unsual situation in that the Vought F4U and Grumman F6F were acquired in parallel. I suspect the Navy really wanted the performance of the Corsair, but the Hellcat appears to have been much better designed for mass production (and accordingly was much cheaper), while having superior handling characteristics ...

That the F6F was (sort of) replaced with the F8F that used the same engine is unusual again, but it probably reflects the F6F's lack performance relative to its peers (not necessarily to the Japanese types it was actually fighting). However, one could argue that in order to achieve a meaningful improvement, the F8F perhaps went a bit too far with regard to light weight design ... combat radius decreased compared to the F6F, and the break-away wing tips never really worked as intended, and in the end were fixed in place and the Bearcat was given a fairly low G limit (for a fighter).

(There was also the F7F Tigercat with the same R-2800 engines of course, but I'd phrase the rule as "no single-engined fighter is replaced by a new single-engine design using the the same powerplant".)

Regards,

Henning (HoHun)

 

[yasotay]

Logistics. Limited space.on ships for multiple engine types and varied specialized equipment are not efficient.
Training. While certainly different from F4F, the F6F was not a leap for pilot training. F4U was significantly different, requiring longer training cycle (if I remember correctly).
Technology. USN, arguably the most resistant to change of the two services was exceedingly comfortable with radial engines. With an existential threat it was not time to experiment.
Threat. The Japanese aircraft did not drastically out perform USN fighters for the most part. Drastic change increases risk. Not something commanders are excited to do in combat.

 

[Justo Miranda]

I heard rumour that TsAGI analysis found that the Ta-183 Design II would have shed its tail (although the IAe 33 Pulqui II seems to have eventually managed to make a somewhat similar t-tail work). What other issues did late war WWII designs have?

Ju EF 128 intakes might have had a lot of duct losses, the Gotha P.60 upper intake might have had issues with air-pressure fluctuations with variations in angle-of-attack, the later Messerschmidt P.1112 design intakes seem even more dubious... would any of these have worked adequately? It is interesting to think about.

With more than 75 years of hindsight - what other ideas can we rule out? Which aircraft might have gotten off the ground?

Early in 1944 Kurt Tank concluded that the performances demanded by the OKL for the future air-superiority jet fighter could not be reached using neither the Jumo 004C nor the HeS 011A, at a time when British turbojets already generated over 2,000 kp. The solution seemed to be a compound power plant that combined the endurance of the turbojet with the bi-propellant rocket punch.



Combining the use of both types of engines, the new fighter would have great operational flexibility: It could act as a point-defence interceptor, using the full power of the two engines, to reach the combat ceiling in the shortest time possible; it could also carry out air patrol missions equipped with droppable fuel tanks for increasing endurance, and using the extra speed of the rocket to very fast reach the interception area, or it could also get away from numerically superior enemy by climbing above the operational ceiling of the fighters of the Allies.



The twin-boom configuration with short fuselage, to avoid the thrust loss in the turbojet tailpipe, also limited maximum speed due to the drag penalty generated by the tailplane. To solve the problem, Dipl.-Ing. Hans Multhopp proposed the adoption of a T-tailplane, a too radical configuration that was object of criticism by the Technisches Amt. Its main objection was based on the danger posed by the tailplane to a pilot attempting to bail out at high speed. The ejector seat designed in 1942, to equip future versions of the Fw 190, could launch the pilot at a height of 2 m above the cockpit floor, with a margin of 43 cm over the tailfin. But the T-tailplane, designed to avoid the turbulent airflow generated by the cockpit hood, had to be installed more than three meters high above the level of the cockpit floor to be effective.



The Technisches Amt calculated that during an ejection at critical Mach number, the T-tailplane would reach the pilot in only 0.018 seconds. In 1944, the most effective ejector seat of the world was the Heinkel Kartusche propelled by an explosive cartridge with 30 grams of powder, with an ejection speed of 11 m/sec and 12 g. It was designed for speeds not exceeding 700 kph. At 1,000 kph and using a T-tailplane it was necessary to increase the ejection speed to 200 g, with equally lethal effects for the pilot.



In January 1944, the firm Focke-Wulf proposed to the OKL a first transonic design called P.011.001, described in the Baubeschreibung Nr.279 dossier as Projekt V. It was a high-altitude interceptor of the Moskitojäger class (De Havilland Mosquito hunters) with light armament and a compound powerplant formed by a HeS 011A turbojet, with 1,115 kp static thrust, and a bi-propellant rocket motor Walter HWK 109-509 B-0 with 350 kp peak thrust. This was the first design of the firm in which the phenomena of compressibility buffeting, local transonic flux, air viscosity in the boundary layer and Mach critical number, as defined by the aerodynamicist of the LFA Institut, were taken in account. A frontal air-intake was adopted to delay the appearance of vibrations, and a 37/43 degrees double swept wing, with 9 to 13 per cent chord/thickness ratio, served to delay the back displacement of the lift centre of pressure and aileron reversement. To facilitate manoeuvrability at high speeds, the tips of the ailerons were clipped.



To avoid that the 38 degrees swept T-tailplane were affected by the fuselage turbulence at critical Mach numbers, it was installed on a long tailfin with 60 degrees rear swept. This configuration worsened the usual lateral stability on short-fuselage aircraft. During the Korean War, The Soviet MiG-15, that was nearly two meters longer than the P.011.001, suffered directional snaking problems at high speeds that affected weapon precision during combat manoeuvres.



Several attempts made to eradicate this problem included the extension of the tailfin up to 3.5 m and the total length of the plane to 8.9 m, as well as increasing the dihedral angle of the tailplane up to 11 degrees, which made the ejection problem even worse.

To reduce the height of the tailplane, wind tunnel tests were carried out with a scale model equipped with an inverted-Vee tailplane. But it was verified that the new configuration increased drag, because of the vortex generated in the junction between the tailfin and the tailplane.



The P.011.001 should be built in light alloy using the well proven technology of the Fw 190. The wings, spanning 8.7 m with an area of 17 sq. m and a chord of 306 cm at the root, contained 1,400 litres of K1 heavy kerosene for a 600 km endurance using the turbojet. The fuselage, with egg section, housed the landing gear, the pressurised cockpit with ejector seat and Revi 16C gunsight, two MG 17 machine guns, two MG 151/20 rapid-fire cannons, one rocket propellant tank, containing 1,800 litres of T-Stoff for 210 seconds of rocket powered flight, one rocket propellant tank containing 800 litres of C-Stoff, the turbojet, the rocket engine and the electronic equipment.



Designed as a Moskitojäger, the P.011.001 was insufficiently armed to combat the four-engine heavy bombers. In 1944 the standard armament of an Fw 190 A-7/R2 sturmböck (assault rammer) were two MG 17, two MG 151/20 and two MK 108/30 heavy cannons. Despite offering an estimated maximum speed of 925 kph and one absolute ceiling of 12,600 m, the propulsion system was a victim of the Technisches Amt criticism who have had very bad experiences with the Messerschmitt Me 163 and its rocket propellants, dangerous substances.



They argued that the new fighter should only be propelled by one turbojet. Therefore, on February 1944 the project was redefined as P.011.018a, a jet fighter propelled by a HeS 011 A-0 turbojet with 1,300 kp static thrust, with the armament of a zerstörer (bomber destroyer), four MK 108/30 heavy cannons with 100 rounds per gun.



To maintain the performance of the P.011.001 at heights above 11,000 m, it was necessary to design a new type of wings, spanning 10 m, constructed in Dural and plywood, with 40 degrees rear swept, 8 per cent thickness, 24 sq. m surface and sharper aileron tips to facilitate manoeuvrability in the rarefied air.



Each wing panel housed six fuel tanks, totalling 1,440 litres of K1 heavy kerosene, together with the elevons and hydraulically-operated flaps. The tailplane sweep angle was increased to 35 degrees and the tailfin swept to 66 degrees, bringing the overall length to 9.5 m. The tailplane dihedral angle was also augmented to 15 degrees to improve longitudinal stability. The windshield was advanced 25 cm to increase the visibility of the pilot during take-off, reducing the length of the nose leg, so that the ground incidence would change from 8 to 5 degrees. The cockpit hood was extended 76 cm to reduce the dorsal turbulence and a fuel tank of 170 litres was installed in the space behind the ejector seat.



It was an aerodynamic design far superior to that of its British contemporaries Gloster E5/42, De Havilland Vampire and Martin-Baker MB.6. The P.011.018a was also too advanced for the mentality of the OKL. Coming ahead of the predictable objections of the Technisches Amt, Kurt Tank designed a more conservative version as well, with reduced armament and a conventional tailplane. This new configuration, described in the dossier Baubeschreibung Nr.252, was presented to the OKL at the same time than the P.011.018a to avoid the total rejection of the project. Both designs received the official designation Ta 183, been described in the specialized literature as Ta 183-I/Ta 183 A and as Ta 183-II/Ta 183 B.



On 15 July 1944, the Technisches Amt requested through Proposal 222/I the design of an air superiority fighter, powered by a HeS 011 A-0 turbojet, in the Jägernottprogramm (emergency fighter program) contest. The new aircraft should reach a maximum speed of 1,000 kph at 7,000 m, with a service ceiling of 14,000 m, an armament of two MK 108/30 heavy cannons with 60 rounds per gun and a fuel capacity of 1,000 litres. A high proportion of sparstoffe (non-strategic materials) such as steel, wood and plastics should be used for its construction.



The OKL ordered that large-scale production should start in February 1945 and reach a monthly production rate of 5,000 fighters in June. Initially the projects presented were the Blohm und Voss P.213.03, Heinkel P.1078 C, Junkers EF.128, Messerschmitt P.1101, P.1110/I and P.1111, as well as the Focke-Wulf Ta 183 A, Ta 183 B and Flitzer III. Also presented out of date, the projects Arado E.581-5, Heinkel He 162 D, Henschel P.135, Messerschmitt P.1116 and the prototypes Horten Ho 229 and Junkers Ju 388 J, which did not compete for the HeS 011 but for the industrial resources associated with the Jägernottprogramm.



In August, the RLM expanded these standards requesting that the new fighter could be easily modified into a twin seat configuration for tasks of night fighter and conversion training. It should also be structurally feasible to install a bi-propellant rocket motor. At the end of the same month the Technisches Amt recommended the installation of nose air intakes and 40 degrees swept wings, a requirement that eliminated Heinkel and Junkers projects, the Messerschmitt P.1110/I and P.1111 and the Focke-Wulf Flitzer III. In September, it was decided to expand the fuel capacity up to 1,400 litres, required to fly for 30 minutes at full throttle.



Failure of the tests carried out with the Drägerwerk-Lübeck, Watanzug pressure suit, necessitated the installation of a pressurised cockpit, with ejector seat and frontal protection against 12.7 mm shelling and against 20 mm shelling from the rear. In October only two contestants remained: the Focke-Wulf Ta 183 A and the Messerschmitt P.1101, a design capable of reaching transonic speed during combat diving, without losing manoeuvrability. The wind tunnel test on the P.1101 models, performed by the AVA-Göttingen institute during the autumn of 1944, revealed that the maximum speed would still be lower than their expectations.



The reason was the turbulence generated in the joint of the rear fuselage and the engine nacelle, that had an '8' shaped section. It was discovered that the airframe generated a triple shock wave at transonic speed. The first one was formed around the cockpit hood, the second over the wing and the third one over the tailplane. The shock waves overlapped among each other with a braking effect similar to an arrow going through three disks of felt launched in the air.



The Messerschmitt designers tried to solve the problem replacing the cockpit hood with another with low drag type Rennkabine, originally designed for a high-speed version of the Me 262. Wind tunnel test performed with a 'V' ant 'T' shaped tailplanes revealed that such modifications did not substantially improve aerodynamic performance and the P.1101 was cancelled at the end of 1944.



During the selection process, the Ta 183 A suffered numerous modifications that gave way to the version Ta 183 A-0, winner of the contest. The 'razorback' dorsal spine was replaced by a triangular-section dorsal structure which served as the basis for the tailfin, thus providing the necessary space for electronic equipment and a 215 litres fuel tank. The wing chord was reduced from 252 to 235 cm and the wing area to 22.5 sq. m. The tailfin swept was of 60 degrees, the overall length of 9.2 m and the height of 3.5 m. The tailplane sweep angle was increased to 45 degrees and the ground incidence to 7 degrees. The rear section of the hood received a metal coating as additional protection for the pilot head and shoulder.



The position of the armament was also modified by positioning the cannons of the lower level further to the rear and increasing the ammunition tank capacity to 120 rounds per gun. The curvature of the nose was reduced to improve the pilot visibility and a new windscreen was designed with 50 mm thick armoured glass and two triangular, electrically heated, 30 mm thick side panels. The reflex gunsight was replaced by a new gyroscopic gunsight of the type EZ 42 Adler and it was proposed to the OKL that the turbojet be replaced by a HeS 011 A-1 with 1600 kp static thrust. The nose leg was retractable backwards after rotating 90 degrees. The main undercarriage legs were retractable forwards, and were housed to both sides of the air duct.

The estimated maximum speed for this version was set at 960 kph and the service ceiling at 14,400 m, with an initial climb rate of 20 mps.



The technical specifications of the Ta 183 A-1 Huckebein production version were published on 28 March 1945. The main innovation was the addition of five weapons racks, mounted beneath the wings and fuselage belly, which could alternatively be used to carry the standard droppable fuel tanks of 300 litres. The ventral rack was located inside a cavity that housed the upper half of the tank to reduce the drag. The capacity of the dorsal fuel tank was increased to 260 litres and the maximum take-off weight up to 5,100 kg. The weight gain required extending the wing area to 23 sq. m and the chord wing up to 248 cm.



The ailerons tips were clipped to improve the rolling at high speed. The expected electronic equipment consisted of a FuG 15/ANF2 direction finder, a GEMA FuG 25a Erstling IFF device and a Lorenz FuG 125a / EBL 3F Hermine radio navigation device. For the projected installation of a radar, necessary room was provided for the electronic equipment ahead of the instrument panel. The nose radome of the parabolic mirror would reduce the pilot visibility, a defect that was attempted to be compensated by reducing the ground incidence to only 3 degrees.



With 1,700 litres of internal fuel, the Huckebein would have a range of 1,740 km. This range could be extended to 3,200 km with the addition of five external drop tanks. In clean configuration, the take-off run was estimated at 650 m and the landing at 555 m. To operate from short runways the Ta 183 A-1 could use two Rheinmetall-Borsig Ri-502 droppable rocket boosters, with 500 kp peak thrust each and 6 seconds of life. In day fighter configuration, with only two MK 108/30 heavy cannons, Huckebein could carry under four wings air-to-air Ruhrstahl-Kramer X-4 missiles or three Trommelanlage containers with 30 air-to-air R4M unguided Rockets each. In the zerstörer (bomber destroyer) configuration he could carry a Rheinmetall-Borsig MK 112/55 heavy cannon in the ventral rack capable of dismantling a B-29 with a single hit.



In the schlechtwetterjäger (all weather fighter) configuration it could carry four Rheinmetall-Borsig R100 BS unguided rockets, but its use required the installation of a FuG 217 J Neptun Liliput rangefinder radar. In nachtjäger (night fighter) configuration it would use a radar FuG 222 Pauke S with a parabolic mirror of 45 cm diameter and one radar operator seated in tandem behind the pilot. In schlacht (ground attack) configuration, it could carry 45 antitank rockets Panzerblitz-2 of 88 mm, in three containers slung under the wings and fuselage belly, or six WK 14 BS incendiary rockets of 280 mm slung under the wings. In jabo (antiship) configuration, it could carry one SD 500 bomb or one BT 200 torpedo-bomb under the belly.



On 30 August 1944, the Messerschmitt Project Bureau decided to build a prototype of P.1101 powered by a Jumo 004B turbojet. This experimental aircraft was expected to be used to test the behaviour of the swept wings in flight and compare it with the data obtained in the wind tunnel by the scientists of the Deutsche Versuchsanstalt für Luftfahrt (DVL) who had recommended the cancellation of the project. Doubts about possible discrepancies between the behaviour predicted by theorists and actual flight at transonic speeds also affected the designers of the Huckebein project.



In December 1944 Kurt Tank decided to build four prototypes called Rechnerische Ankündigung (Ra) to test in flight the basic airframe of the Ta 183 powered by different engines. The program should start on January 1945 with the construction of the Ta 183 Ra-1, an advanced version of the P.011.001 powered by a HeS 011 A-0 turbojet and a HWK 109-509 B-1 bipropellant rocket engine. For safety reasons, the rocket propellants were stored in two detachable tanks slung under the wings.



The 350 litres T-Stoff oxidant tank was positioned asymmetrically to the C-Stoff fuel tank, with only 180 litres of capacity and of shorter diameter, to compensate for the drag braking effect. The K1 heavy kerosene for the turbojet was stored in a rear tank of 290 litres and additional 1,300 litres inside the wings. To improve the longitudinal stability, with respect to P.011.001, the tailfin chord was increased by 10 cm and the sweep angle of the tailplane was reduced to 37 degrees. The tailplane span was increased by 36 cm. The wing span was reduced by 6 cm and the sweep angle to 40 degrees, but the wing surface remained unchanged. When the nose leg was shortened, the ground incidence was reduced by two degrees and the length of the cockpit hood was increased by 68 cm to reduce turbulence on the rudder. The weaponry proposed for this version was two MG 151/20 rapid-fire cannons and two MK 108/30 heavy cannons.



The Ta 183 Ra-2 (20 March 1945) should be powered by a Jumo 004 B turbojet with only 890 kp static thrust. To compensate the reduction of power with respect to the Huckebein, it was decided to increase the chord of the wing up to 248 cm, the wingspan to 11 m and the wing area to 24.7 sq. m. The tips of the ailerons, the tailplane and the rudder were also modified, giving them a rounded shape. The overall length was reduced by 30 cm and the ground incidence became of 5 degrees thus the height being reduced by 35 cm. The Jumo turbojet normally operated with heavy kerosene of type J2, although if necessary, a mixture of B4, 87-octane petrol and motor oil could also be used. The specific fuel consumption was 1-38, higher than that of HeS 011. Therefore, it was necessary to increase the capacity of the dorsal fuel tank in 30 litres. The proposed armament was of four MK 108/30 cannons.



The Ta 183 Ra-3 (January 1945) should be powered by a HeS 011 A-0 turbojet with 1,300 kp static thrust. The main dimensions were the same as those of the Huckebein, except for the chord wing at the root which was 235 cm and the wing area of 22.5 sq. m. Differences with the production version affected the retraction system of the nosewheel, the shape of the windshield side panels and the position of the armament. The capacity of the dorsal tank was reduced to 240 litres.



The Ta 183 Ra-4 (February 1945) should be powered by a HeS 011 A-1 with 1,600 kp static thrust. Basically, it was a Ra-3 with the wing of a Huckebein, a 540 litres dorsal fuel tank, protected by armoured plates, and a single access panel to the guns on each side of the fuselage. The Technisches Amt considered the swept wings of the Ta 183 were potentially dangerous during landing at low speeds. But most of the criticism of its experts were directed against the T-tailplane configuration. They argued that it was too heavy for a fighter, it did not provide enough lateral stability and could not be built on wood. They also considered the front section of the fuselage, a 13 per cent bigger than that of the standard Fw 190, to be excessive.



In February of 1944 Kurt Tank sent a set of drawings and calculations to the RLM contained in the dossier denominated Baubeschreibung Nr.252 describing the ‘soft’ version of the Ta 183, denominated Ta 183 B (P.011.037a). The cross section of the fuselage was 24 per cent lower than that of the Ta 183 A, the armament was reduced to only two MK 108/30, the cockpit was moved backward 1.5 m and the tailplane was placed at the same height as the head of the pilot. The wing span was reduced by 50 cm and the sweep wing angle to 34 degrees, the wing roots were moved to the rear by 90 cm and the tailplane was moved forward by 72 cm. The internal fuel capacity did not change.



This basic design evolved throughout 1944 trying to adapt to the changing demands of the Jägernottprogramm. In its version P.011.039a (February 1945) the cockpit had been advanced 36 cm to improve the visibility of the pilot at landing, the wings had been advanced 11 cm to preserve the longitudinal stability, altered by the weight of the new fuel tank of 250 litres installed over the air duct. The entire tail section was designed in a way that could be constructed in wood and was interchangeable with that of the Huckebein. The Ta 183 B was superior to all versions of the Ta 183 A in ceiling and maximum speed, thanks to its smaller front section and the lower structural weight of the airframe.

 

[Justo Miranda]

Post-2

 

[Justo Miranda]

When the USSR revealed the MiG-15, during the May 1949 parade, Western analysts noted that it strongly resembled the German Focke-Wulf Ta 183 A-0 jet fighter project.

Many Western books and magazine articles stressed the similarity of both designs and they assumed that the general aerodynamic layout of the MiG was influenced by German designs.

Perhaps the Soviets had continued to develop the Ta 183 after the war, as they did with the Junkers Ju 248, EF 126, EF 127, EF 131, DFS 346 and the Heinkel He 343/Ilyushin Il-22 projects.

Why not?

The USSR was within its rights to use the technology conquered with the sacrifice of its soldiers.

The importance of the German scientific and technological achievements was well understood both in the USSR and in other countries.

After the war ended, the Allied powers raced to seize aeronautic technology in occupied Germany and the aerodynamic configuration of these German projects, proof-of-concept prototypes, weapons, and operational airplanes were used in the first generation of the Cold War jet fighters.



The nose air intake/tubular fuselage/rear swept wings and tail surfaces configuration of the Messerschmitt P.1101 and Focke-Wulf Ta 183 fighters were used in North American F-86 Sabre, MiG-15 Fagot, MiG-17 Fresco, Lavochkin La-15 Fantail, Dassault MD 450 Ouragan, Dassault MD 452 Mystère, Nord 2200, Tank IAE 33 Pulqui II, Fiat G.91 Gina and Fuji T-1.

The delta wing configuration of Lippisch DM-1 and Messerschmitt P.1112/S2 was used in the Convair XF-92, Convair F-102, Nord 1402 Gerfaut, Sud-Est S.E. 212 Durandal, Dassault Mirage I, Avro 707, Boulton Paul P.111, Boulton Paul P.120, Handley Page H.P.115, Fairey Delta 1, Fairey Delta 2, BAC 221 and Short SC.1.

The maximum speed of the first prototypes XF-92 and YF-102 was limited to 0.98 Mach, due a transonic drag much higher than expected, but the problem was solved in December 1954 using the aerodynamic principle named area rule, patented by Junkers on March 1944.

Swept wings with two trailing-edge fins configuration from Arado E.583 and Junkers EF.128 projects was used in the Chance Vought F7U Cutlass naval fighter.

The “bat wing” of the Messerschmitt Me P.1109-01 and Blohm und Voss P.208 projects was used in 1996 in the prototype Boeing Bird of Prey.

The oblique scissors wing of the Messerschmitt Me P.1109-01 and Blohm und Voss P.202 projects were flight tested in 1979 with the NASA Ames AD-1 research airplane.

The forward-swept wing of the German projects Heinkel He 162 B, Blohm und Voss P.209.02, BMW Strahlbomber II, and Focke-Wulf P. 03028, was flight tested with the Grumman X-29 research plane in 1984.

The butterfly tailplane of the Heinkel P.1079A and Messerschmitt P.1110 projects were used in 1951 in the Supermarine Type 508 prototype and in the Fouga CM.170 Magister jet trainer in 1952.

The Versuchsflugel II crescent wing of the Arado Ar 234 V16 project was used in the Handley Page H.P.88 research plane in 1951 and in the Handley Page Victor strategic bomber in 1952.

The tailless configuration of the Messerschmitt Me 163 Komet was flight tested in the research planes de Havilland D.H.108 in 1946, Northrop X-4 in 1948, Payen Katy in 1954 and in the Douglas F4D Skyray naval fighter in 1951.

The double-delta configuration of the Henschel P.130 project was used by SAAB in their J35 Draken jet interceptor in 1955.

The jet/rocket mixed propulsion system of the Messerschmitt prototype Me 262 V074 and the Focke-Wulf Projekt VI Flitzer were used in the French interceptor Dassault Mirage IIIC in 1961 and in the British research airplane Saunders-Roe S.R. 177 in 1947.

The variable-geometry wing of the Messerschmitt P.1102-05 was used in the Bell X-5 and Mirage G prototypes, in the Grumman F-14 Tomcat naval fighter, in the MiG-23 fighter-bomber and in the Panavia Tornado bomber.

The radar rotating antenna of the airborne early warning airplanes Grumman E-2 Hawkeye and the AWACS Boeing E-3 Sentry, was developed in 1944 for the Arado Ar 234 C-3, to track a bomber stream up to distances of 45 km, using a FuG 244 Bremen 0 radar set with a rotating disc above the fuselage.



The heat-seeking missile AIM-9 Sidewinder and the Soviet copy R-13/AA-2 Atoll were based on the infrared homing devices and infrared proximity fuses developed by AEG and Kepka for the German missiles Messerschmitt Enzian, Henschel Hs 117 Schmetterling, EMW Wasserfall and Ruhrstahl-Kramer X-7 Rotkäppchen.

The annular wing developed by von Zborowski for the Heinkel Wespe VTOL project, was flight tested in 1958 with the French prototype SNECMA Coléoptère.

The French DEFA and British ADEN 30 mm cannon were developed from the German Mauser MG 213C.

The USAAF 0.60-caliber heavy machine gun was a straight copy of the German Mauser MG151.

The Mighty Mouse air-to-air unguided rockets fired by the all-weather interceptors Lockheed F-94 Starfire, Northrop F-89 Scorpion and North American F-86 D Sabre Dog during the Cold War, were developed from the Rheinmetall R4M Orkan 55 mm rocket, and their automatic firing radar system probably was a development of the German FuG 222 Pauke S fire control radar with Oberon-Elfe predictor system.

The ramjet propulsion of the German projects Lippisch P.13a, Skoda-Kauba SK P.12, Heinkel P.1080, Focke-Wulf Ta 283 and Messerschmitt P.1101L was flight tested by the North American F-51D c/n 44-63528 in 1946, the Lockheed F-80 Trijet in 1948, and the French prototypes Leduc 021 and Sud-Ouest SO 9000 Trident in 1953.

The turboprop configuration of the Focke-Wulf P.0310226-17 project was flight tested in 1953 with the McDonnell XF-88B prototype, and by the Republic XF-84 H Thunderscreech research plane in 1955.

The canard fore planes of the Blohm und Voss P.217 and Messerschmitt P.1110 (Feb 12, 1945) projects were used by the Dassault Mirage Milan in 1969.

Several versions of the Fieseler Fi 103 (V-1) cruise missile were manufactured in USA, as Republic-Ford JB-2 Loon, in France as ARSAERO CT-10 and in the USSR as the Izdeliye 10.

The EMW V-2 ballistic missile was manufactured in the USSR as the R-1 in 1948, in USA as RTV-G-4 Bumper and developed as the PGM Redstone rocket of the NASA Mercury project in 1958.

The Rheinmetall-Borsig Rheintochter surface-to-air missile concept inspired the Soviet SA-2 (1958) and the US Nike Ajax (1954).

The Doblhoff WNF 342 jet propelled rotor concept was used in the Hiller YH-32 Hornet helicopter in 1950, in the XH-26 Jet Jeep helicopter in 1952, in the Fairey Rotodyne compound gyroplane in 1957 and in the Fairey Gyrodyne prototype in 1957.


The SNECMA Atar 101 French turbojet was developed from the BMW 003 axial-flow turbojet.



However, the MiG-15 seems to be a special case. Over the past 72 years respected authors have published numerous works denying the Focke-Wulf heritage of the Soviet fighter and detailing the differences between the two designs.



They are certainly right about the Ta 183 A-0 Huckebein, which is the version best known for having won the Jägernottprogramm contest.



But the information captured in Berlin about the latest projects of the Bad Eilsen design team comprised eleven variants of the Ta 183 and nine scaled-up and scaled-down associated designs that shared the original basic aerodynamic layout.

These projects differed in the position of the wings (shoulder, mid and low) and tail planes (T, mid and low), had different wings with swept angles between 33 and 43 degrees, tail planes between 35 and 49 degrees swept, and tailfins between 41 and 67 degrees swept, at the leading edge in all cases. Most were equipped with fuselage retractable landing gear, but some retracted on the wings, such as the MiG-15.

The Soviet designers were able to adopt ideas from all of them by concentrating them in a single project.



The fuselage of the MiG-15 (built with Podberezhye semi-monocoque Duralumin structure) and the pressurized cockpit were both based on those of the Junkers Ju 248 V2 captured at Kassel and the ejector seat was based on that of the Heinkel He 162 A-2 captured in Vienna.



The wings were a modification of those of the Lavochkin La-160, which were in turn based on those of the Focke-Wulf designs captured in Berlin by the People's Commisariat of the Aviation Industry, and joined the fuselage in the same position as those of the Junkers Ju 248 V2.



The wing retractable undercarriage and the 45-degree swept tailplane were very similar to those of project Focke-Wulf P.011.025 (November 1944).



The engine was a British design.



But, according to the Soviet designers, the MiG-15 was an indigenous design.



This is true in the sense that they had been able to integrate different German and British technologies into a design adapted to the Soviet manufacturing standards and that no German TsAGI technicians had been involved in this process.



Ironically, the MiG OKB designers used Focke-Wulf T-tail planes on the MiG I-270 rocket fighter prototype and in the MiG-19 prototype SM-2/1, without success.



On July 15, 1944, the Luftwaffe Technisches Amt (Technical Office) requested through Proposal 222/I the design of an air superiority fighter, powered by a Heinkel HeS 011 A-0 turbojet, as part of the Jägernottprogramm (emergency fighter program) contest.



The new aircraft should reach a maximum speed of 1,000 km/h at 7,000 m, with a service ceiling of 14,000 m, an armament of two MK 108/30 heavy cannons with 60 rounds per gun and a fuel capacity of 1,000 liters. A high proportion of sparstoffe (non-strategic materials), such as steel, wood, and plastics, would be used for its construction.



The OKL ordered that large-scale production should start in February 1945 and reached a monthly production rate of 5,000 fighters in June. Initially the projects presented were the Blohm und Voss P.213.03, Heinkel P.1078 C, Junkers EF.128, Messerschmitt P.1101, P.1110/I and P.1111, as well as the Focke-Wulf Ta 183 A, Ta 183 B and Flitzer III.

In October 1944 only two contestants remained: the Focke-Wulf Ta 183 A and the Messerschmitt P.1101, a pod-and-boom design theoretically capable of reaching transonic speed during combat diving without losing maneuverability. But the wind tunnel tests performed by the AVA-Göttingen institute during the autumn of 1944, with P.1101 scale models, revealed that the maximum speed would still be below their expectations.



The reason was the turbulence generated in the joint of the rear fuselage and the engine nacelle, that had an '8' shaped section. It was discovered that the airframe generated a triple shock wave at transonic speed. The first one was formed around the cockpit hood, the second over the wing and the third one over the tailplane. The shock waves overlapped among each other with a braking effect like that of an arrow going through three disks of felt launched in the air.



The Messerschmitt designers tried to solve the problem replacing the cockpit hood with another of low drag, type Rennkabine, originally designed for a high-speed version of the Me 262. Wind tunnel tests performed with 'V' and 'T' shaped tail planes revealed that such modifications did not substantially improve aerodynamic performance and the P.1101 was cancelled at the end of 1944.



During the selection process, the Ta 183 A suffered numerous modifications that gave way to the Ta 183 A-0 version, winner of the contest. The wing chord was reduced from 252 to 235 cm and the wing area to 22.5 sq. m. The tailfin swept was of 60-degrees, the overall length of 9.2 m and the height of 3.5 m. The tailplane sweep angle was increased to 45-degrees and the ground incidence to 7-degrees.



The estimated maximum speed for this version was set at 960 km/h and the service ceiling at 14,400 m, with an initial climb rate of 20 m/sec.



The Technisches Amt considered that the 40-degree (25% chord) swept wings of the Ta 183 were potentially dangerous during landing at low speeds. But most of the criticism of its experts were directed against the T-tail plane configuration. They argued that it was too heavy for a fighter, it did not provide enough lateral stability and could not be built on wood.

The T-tail plane was also too advanced for the mentality of the OKL (Oberkommando der Luftwaffe-Air Command). Its main objection was based on the danger posed by the tailplane to a pilot attempting to bail out at high speed.



The ejector seat designed in 1942, to equip future versions of the Focke-Wulf Fw 190 piston fighter, could launch the pilot at a height of 2 m above the cockpit floor, with a margin of 43 cm over the tailfin. But the T-tail plane, designed to avoid the turbulent airflow generated by the cockpit hood at transonic speeds, had to be installed more than three meters high above the level of the cockpit floor to be effective.



The Technisches Amt calculated that during an ejection at critical Mach number, the T-tailplane would reach the pilot in only 0.018 seconds. In 1944, the most effective ejector seat of the world was the Heinkel Kartusche propelled by an explosive cartridge with 30 grams of powder, with an ejection speed of 11 m/sec and 12 g. It was designed for speeds not exceeding 700 km/h. At 1,000 km/h and using a T-tail plane it was necessary to increase the ejection speed to 200 g, with equally lethal effects for the pilot.



Coming ahead of the predictable objections of the Technisches Amt, Kurt Tank designed a more conservative version as well, with reduced armament and a conventional tailplane. This new configuration, described in the dossier Baubeschreibung Nr.252, was presented to the OKL at the same time than the project P.011.018a to avoid the total rejection of the project. Both designs received the official designation Ta 183, been described in the specialized literature as Ta 183-I/Ta 183 A and as Ta 183-II/Ta 183 B.



In February of 1944 Kurt Tank sent to the RLM (Reichsluftfahrtministerium – Reich Ministry of Aviation) a set of drawings and calculations contained in the dossier denominated Baubeschreibung Nr.252 describing a ‘soft’ second iteration of the Ta 183, denominated Ta 183 B (P.011.037a).

The cross section of the fuselage was 24 per cent lower than that of the Ta 183 A, the armament was reduced to only two MK 108/30, the cockpit was moved backwards 1.5 m and the tail plane was placed at the same height as the head of the pilot. The wingspan was reduced by 50 cm and the sweep wing angle to 34-degree, the wing roots were moved to the rear by 90 cm and the tailplane was moved forward by 72 cm. The internal fuel capacity did not change.



This basic design evolved throughout 1944 trying to adapt to the changing demands of the Jägernottprogramm. In its version P.011.039a (February 1945) the cockpit had been advanced 36 cm to improve the visibility of the pilot at landing, the wings had been advanced 11 cm to preserve the longitudinal stability, altered by the weight of the new fuel tank of 250 liters installed over the air duct.

The Ta 183 B was superior to all versions of the Ta 183 A in ceiling and maximum speed, thanks to its smaller front section and the lower structural weight of the airframe and surely this information was obtained by MiG designers through the captured German scientists.

When the MiG OKB won the March 11, 1947 fighter contest, the MiG-15 production had priority to receive the most powerful RD-45 turbojet (the Soviet version of the Rolls-Royce Nene Mk.I).

The Lavochkin bureau stopped the La-168 development to concentrate their efforts in the design of the La-174, a new fighter that was 340 kg less heavy than the MiG and that would be powered by the less powerful RD-500 turbojet (Soviet version of the Rolls-Royce Derwent V).

The La-174 was a 90% scaled down version of the La-168 and it had no relation to the La-174 TK straight wing prototype.

The aircraft was flown on January 8, 1948, suffering dangerous tailplane flutter and crashed during testing on May 11, 1948.

The defect was corrected in the second prototype La-174D that flew on June 12, 1948.

Combats tests performed in the Tshkalovsk research center proved that the La-174D was superior to the MiG-15 in maneuverability, because its lower weight and excellent wing design compensated for the turbojet's lack of power.

In September 1948 the new fighter was accepted for production, alongside the MiG-15, and officially named Lavochkin La-15 in April 1949.

Operational tests with the 192nd IAP began in May 1949, at Kubinka-Moscow, but the unreliable hydraulic system resulted in undercarriage failures and landing crashes due to the extremely narrow track (1.70 m) of its landing gear.

The VVS had already had problems in 1943 with the landing instability of their Spitfires on rough-field operations and the frequent crashes of the La-15 at side wind were considered unacceptable for a front-line fighter.

Only 235 La-15 fighters were built between December 1948 and August 1949.

The shoulder mounted La-15 wings (with 37º 20’ swept, 25 % chord, 12% thickness, 6º anhedral and smaller span-chord ratio than those of the MiG) were based on those of the La-160. They were more resistant and rigid because they were not designed to accommodate the main undercarriage legs.

But the La-15 wings were more complex to produce, and their light airframe was not sturdy enough to withstand the recoil of a 37 mm cannon.

The more rugged design of the MiG-15 was cheaper and easier to produce.

If the La-15 had been used in Korea against the F-86 fighters it would surely have been more successful in dogfight than the MiG-15, but most Russian historians deny the La-15's involvement in the war.

On the contrary, there are reports in the CIA Current Intelligence Bulletin of multiple sightings of jet fighters with shoulder-mounted wings.

These aircraft were seen by American and British pilots of F-86E, B-26, RF-80 and F-51 aircraft of the UN forces in Korea.

Pilots believed it was a new type of MiG and referred to it in reports as “MiG-17” or “Type-15”.

In late March 1952 a “Type 15” was observed only 100 feet away by the pilot of an F-86E of 4th FIG, 335th FIS. (Report of Lt. James D. Carey published in Time Magazine on March 13, 1952).

According with the CIA-FOIA files and with the reports of the UN pilots, the “Type 15” was sighted 14 times, engaged 10 times, two aircraft were destroyed and 11 damaged.

According to the article published by V. Ilyin, V. Rudyenko and J. Martinek in the Czech magazine Zlinek (Nº 14, vol. 2, 1994) a VVS Fighter Regiment, with twenty-two La-15 airplanes, carried out combat operations in Korea suffering four crashes due to the poor condition of the airfield. The other machines were sent back to the USSR.

Additional information from the specialized authors Mikhail Zhikorov, Warren Thompson and Larry Davis were published at “Wings of Fame” (Volume 1, 1995) and

http://sovietwarplanes.com/board/index.php?topic=1534.0

https://www.aereimilitari.org/forum/topic/9275-lavochkin-la-15-in-corea/

http://sabre-pilots.org/classics/v133duck.htm

http://www.foia.cia.gov/

It is strange that the Soviets did not attempt to use the La-15 against the UN Sabres when the MiG-15s began to be systematically destroyed because of their inferior maneuverability.

So, what is the truth?

Lavochkin La-15 Fantail technical data

Power plant: one Klimov RD-500 turbojet rated at 1,590 kg thrust, wingspan: 28.9 ft. (8.83 m), length: 31.3 ft. (9.56 m), height: 12.8 ft. (3.9 m), wing surface: 179.6 sq. ft. (16.16 sq. m.), take-off weight: 8,500 lb. (3,850 kg), max speed: 638 mph (1,026 km/h), ceiling: 44,280 ft. (13,500 m), armament: three 23 mm NR-23 cannon, equipment: pressurized cockpit with (German) ultraviolet illumination of the instrument panel, ASP-1N gyroscopic gunsight (direct copy of the British Mk.IID), KUS-1200 speedometer, M-46 Machmeter, V-15 altimeter, RSI-6K R/T, S-13 gun camera and ejector seat.



To test the limits of the La-168 aerodynamic configuration, the La-176 prototype was built during the summer of 1948.

The new airplane was flown on September 22, 1948, fitted with 45-degree swept wings (25% chord) and three fences in each wing, reaching Mach 0.98 top speed only.

The RD-45 was replaced by a Klimov VK-1 (the Soviet version of the Rolls-Royce Nene Mk.2) with 2,700 kg thrust.

On December 26, 1948, the La-176 exceeded the speed of sound diving from 39,360 ft. (12,000 m) over the Black Sea.

On February 3, 1949, the prototype disintegrated in flight when the canopy locks failed near Mach 1.

Lavochkin La-176 technical data

Power plant: one Klimov VK-1 turbojet rated at 2,700 kg thrust, wingspan: 28 ft. (8.59 m), length: 36 ft. (10.97 m), wing surface: 203 sq. ft. (18.25sq. m.), take-off weight: 10,209 lb. (4,631 kg), max speed: Mach 1.021, ceiling: 49,200 ft. (15,000 m).

 

[Justo Miranda]

Russian Fakes​

At the beginning of the Cold War the Soviets adopted a policy of maximum secrecy to hide their technical inferiority. In 1947 the U.S. intelligence organization lacked the resources to penetrate the Soviet curtain of secrecy to collect information concerning military bases or atomic research sites far from Moscow.

According to the Air material Command's Intelligence Department, the 95 per cent of the information available on the new types of Soviet airplanes had been obtained during the annual Soviet Air Day Show.

During the Summer Aviation Day display at Thusino Airfield on 3 August 1947, the Soviets revealed the existence of six new types of jet fighters, including the Lavochkin La-160 prototype fitted with swept wings. The variety of unknown models caused some confusion among the journalists attending the event and it was the origin of a lucrative traffic of tricky photographs coming from East Germany that remained active until the early sixties.

The introduction of the MiG-15 in North Korea in August of 1950 was a bad surprise for the Western World and aviation specialists had the temptation to speculate what could be the next Soviet fighter.

Within this concept, in which the mystery and the lack of information about what happened at the other side of the Iron Curtain favored the curiosity of the western public.

All the airplanes and popular science magazines, as well as Jane’s military hardware books, carried stories of rumored Russian fighter that would replace the MiG-15.

Most of these rumors were related to disinformation tactics employed by both sides and the legend was perpetuated until the early sixties.

Fake MiG-17​

In the second half of 1945 the AI radar Gneys-5 passed the State acceptance test.

On February 26, 1946, Tupolev OKB was ordered to design a night fighter version of the Tu-2 fast bomber, with 680 km/h top speed, 10,000 m ceiling, 2,000 km range and Gneys-5S airborne radar. That was enough to intercept the nuclear armed B-29 American bombers.

The Tu-1 prototype flew on March 22, 1947, powered by two AM-43V experimental piston engines, reaching 641 km/h and 11,000 m ceiling. It was mistakenly regarded by NATO intelligence as a likely mass-production type and assigned the Frosty reporting name.

Between March and October 1947, the prototype was flight tested with two types of AI radars: Soviet Gneys-7 and German Telefunken FuG 200 SN-2/SN-2d.

On both types, the transmitting dipoles were in the forward fuselage and the receiving antennas in the wings.

During the tests it was discovered that the glare or Gneys radarscope ruined the night vision of the pilot, who also needed to keep an eye on the airspace around him.

By the time the Tu-1 was flown the prototype of the B-36 American super bomber had already reached 555 km/h flying at 11,280 m.

Therefore, further work on Tu-1 was discontinued.

What the VVS needed at the end of 1947 was a fast jet night fighter with 2,000 km extended range and a second crewmen to take care of the radar.

However the aerodynamic drag generated by the Gneys dipoles and antennas caused an unacceptable loss of speed.

The Bell SCR 720 B AI radar mounted in the Black Widow and D.H. Mosquito NF 36 western night fighters used one parabolic antenna that was installed internally within an aerodynamic radome of dielectric material placed in the nose of the aircraft.

But both the Americans and the British refused to share their centimetric wave lengths technology.

In January 1948 the Soviet Council of Ministers issued a decree calling for a high-performance, long-range, all-weather fighter capable of mounting standing patrols and intercepting the Strategic Air Command bombers far from their targets.

The PVO staff estimated that to achieve this objective a plane with performances similar to those of the MiG-15 would be necessary.

But the fighter would also have to carry a large amount of fuel, a radar of 100 kg and a second crewmen.

To meet the conditions of the specification it would be necessary to use at least two RD-45F centrifugal engines rated at 2,270 kg thrust each, the best turbojet available at the time.

If installed under the wings of the new interceptor, both engines would have generated an unacceptable loss of speed owing to their rather large diameter of 1,273 mm.

Nor would it have been aerodynamically effective to install them under the fuselage belly in side-by-side configuration.

The American long range fighter Bell XP-83 built in 1944 with this basic configuration it had to be canceled due to its poor performance.

The MiG OKB decided to build the I-320 heavy fighter (a 50 per cent scaled up version of the MiG-15) powered by two RD-45F turbojets mounted inside the fuselage in stepped configuration. The forward engine exhausting beneath the fuselage belly and the aft engine exhausting at the tail.

Both turbojets aspirated through the same nose air intake.

This unusual configuration that generated less drag, had already been studied in 1942 by the German designers of the Arado Ar 240 TL heavy fighter project.

And it had also been studied independently by the Japanese designers of the Yokosuka R2Y2 Keiun jet bomber in 1945.

It was expected that the I-320 could operate as high-performance interceptor when the two afterburners were engaged and that could also operate as escort fighter using a single engine to save fuel.

On December 7, 1948, the Council of Ministers issued a decree calling for the development of a new generation of AI radars able to operate on centimetric wavelengths using the German technology of the Telefunken radars FuG 222 Pauke S, FuG 240/3 Berlin N3 and FuG 244 Bremen 0.

The centimetric wavelengths conversion started with the AI radar Slepushkin Toriy which provided search, track and gun-ranging using a single parabolic antenna with 60 cm of diameter.

But Toriy proved to have unreliable and too difficult to use, its manually operated antenna based on that of the FuG 244, has scanning angles of only +30 and -30 degrees and could not operate at the 8g design limit of the I-320.

The radar was designed with a range of 15 km, but during flight tests with the I-320 prototype, it only managed to detect a Tupolev Tu-4 bomber (the Soviet version of the B-29) 7 km away.

The I-320 looked like a MiG-15 with a second turbojet mounted in redan configuration, one radar radome fitted at the top of the nose and a Mosquito-style, two-seat unpressurized cockpit.

The R-1 prototype flew on April 16, 1949, but during the State acceptance trials the plane experienced the same tendency as the MiG-15 to drop a wing at high-speeds.

The appearance of the aerodynamic phenomenon valyozhka (spontaneous rolling) at Mach 0.895 made it necessary to limit its maximum speed, to avoid structural damage.

The R-2 prototype was flown in December 1949 reaching 1,047 km/h top speed and 15,000 m ceiling powered by two VK-1 turbojets rated at 2,700 kg thrust each.

In July 1951 its unreliable Toriy-A was replaced by one Korshun AI radar set, based on the FuG 240/3, which offered better performance although still not adequate.

Both types using manually operated scanners, but the Korshun's parabolic antenna is only 45 cm in diameter and could operate at greater scanning angles.

The VK-1 turbojets proved to be too thirsty and caused the I-320 to only be able to reach the necessary range using two underwing drop tanks.

The I-320 was cancelled in the spring of 1951 in favor of the Yak-25 Flashlight fitted with one Sokol (FuG 222) radar with 1 m of diameter parabolic mirror and powered by two wing-mounted, axial-flow turbojets.

MiG-I-320 R-2 technical data

Wingspan: 46.6 ft. (14.22 m), length: 51.7 ft. (15.77 m), height: 16 ft. (4.88 m), wing surface: 458 sq. ft. (41.2 sq. m), take-off weight: 26,190 lb. (11,864 m), maximum speed: 660 mph (1,047 km/h), ceiling: 49,200 ft. (15,000 m), range: 2,075 km with two underwings drop tanks, equipment: RV-2 radio-altimeter, Barii IFF transponder and RSIU-6 R/T.

Certain information on the MiG I-320 coming from East Germany was filtered to the western press in 1951 and it was interpreted as the description of an advanced version of the well-known MiG-9 with side-by-side axial-flow turbojets, swept wing and tail surfaces.

In December 1951 Flying magazine published an illustration and a three-view drawing of the “Super-MiG/MiG-17” with a landing gear like that of the MiG-15, radar snout and four belly mounted cannon.

According to Flying the new fighter had been identified by USAF in Korea as "flat" MiG.



On February 16, 1953, American Aviation Magazine published an illustration coming from Associated Press Wirephoto depicting an operational "MiG-17" with No. 157.



On April 13, 1953, LIFE magazine publishes the schematic cutaway of a Soviet jet fighter that defines as “latest MiG model 17 with double jets, all weather radar, 50,000 ft. ceiling, 6,000 ft/min climb rate, 650 mph top speed, 15,000 lb. take-off weight and four belly mounted cannon”.

According to LIFE the “MiG-17” has not yet been used in Korea.



In June 1953, the Air Trails magazine published an article by James L. Pech entitled “Inside Story of the MiG-19” that included a three views drawing based on the one published by Flying, an illustration depicting an operational aircraft with the number 107 and a detailed cutaway.

According to Air Trails, the new Soviet fighter had been revealed in Tushino Air Show in summer of 1952 and was sighted in Korea in October.



The same information was published by Italian magazines Cielo (December 1953) and L’Ala D’Italia (April-May 1954).



The Air Trails article was widely circulated among modelers and aircraft enthusiast, prompting the model maker Paul Lindberg to release in 1954 the1/48 scale plastic kit Nº R521-79 called “Russian MiG-19”, engineered from drawings in Air Trails. In the 1955 and 1959 editions the denomination in the box art changed to “Russian Jet Fighter”.



This “Soviet fighter” became so popular that it was used in the cover color of Men in Action (September 1955).



According to an article by Jean-Claude Mermet published in Aéro Journal Nº 9 (October-November 1999), a three views black silhouettes of the "MiG-19" was included in L'Armee de L'Air aircraft identification chart of 1955.



In 1957 the Japanese manufacturer of model kits Bachmann launched the 1/200 scale version of the Air Trails fighter.



Ironically in 1963 the Soviet State Trading Company bought the Lindberg mold to produce the “MiG-19” kit in the Moscow City Council of National Economy-Factory of Metal and Plastic Toys.



According to an article by W.R. Matthews published in Flying Review (March 1964), for some extraordinary reason, possibly connected with the activities of Russian counterintelligence any reference to MiG OKB was omitted from the little leaflet which accompanies the kit. The fact that most of the information leaked to the West belonged to failed Soviet projects seems to support this theory.

 

[Justo Miranda]

Fake MiG-19

​

The IAE 33 Pulqui II was a transonic version of the Focke-Wulf Ta 183, developed by Kurt Tank in Argentina between 1947 and 1955.

Two test gliders and five prototypes were built of this aircraft. The scheduled production of 100 operational units was cancelled for political reasons in 1957.

The first glider was built with the collaboration of Reimar Horten in early 1948, to study the aerodynamic behavior of the design at low speeds. It flew for the first time on 20 October, towed by a Glenn Martin W-139 bomber, proving that the 55-degree swept tailfin did not offer sufficient lateral stability. The second glider was built with a 35-degree swept tailfin, which surface had been increased by 30 per cent.

The construction of two prototypes started in 1949. The IAE 33-01 was used for structural testing and the IAE 33-02 was fitted with a Rolls Royce Nene II centrifugal turbojet with 2,270 kg static thrust. The first flight was made on 16 June 1950 showing lateral instability at speeds above 700 km/h and loss of lift at low speeds. It was modified with the installation of a wider rudder and wing leading extensions, a pressurizing system and a cockpit hood reinforced with metallic strips. A deflector was added over the nozzle to protect the rudder from the heat of the exhaust gases.

On 23 October, during the second test flight, the IAE 33-02 climbed to 8,000 m in 6 minutes reaching a speed of 1,040 km/h. During the third flight, it reached an absolute ceiling of 13,000 m, landing at 170 km/h without loss of lift. It was destroyed due to wing structural fail on 31 May 1951.

The IAE 33-03 was the preproduction version. It had an increased fuel capacity and better lateral stability, resulting from the installation of a new flight control system. Its flight testing began at the end of 1951, getting destroyed due to an engine stoppage on 9 October 1952.

The IAE 33-04, built in 1953, was equipped with four hydraulic operated airbrakes on the rear section of the fuselage and fences on the upper side of the wings, to delay the migration of the center of pressure at transonic speeds. It had an improved pressurized system and was armed with four Hispano-Suiza Mk.5 cannons of 20 mm installed under the air duct. During the flight tests performed in 1954, the 04 reached an absolute ceiling of 15,000 m and 1,080 km/h maximum speed.

The IAE 33-05 was started in 1957, without fences but with four anti-spin fins in the rear section of the fuselage, flying for the first time on 18 September 1955 and the last in 1960. The IAE 33 airframe was built entirely of light alloy. The wings, spanning 10.6 m, with 40/45-degree rear swept angle and 8 per cent thickness, housed two fuel tanks with 150 liters of capacity each, two with 154 liters, two with 170 liters and two with 160 liters, as well as the ailerons and the hydraulically operated flaps.

The fuselage housed the pressurized cockpit, with armored windshield, one Mk.IIc gyro-gunsight from a Gloster Meteor F.Mk.4, and Martin-Baker Mk.1 ejector seat, the armament, the landing gear, the air intake with bifurcated air duct, three fuel tanks with 656, 485 and 156 liters of capacity, the engine pressure compensation chamber, the turbojet, the tailpipe, four airbrakes ant the 35-degree rear swept tailfin. The tail plane, with 45-degree rear swept, was fitted with an electric motor to vary its incidence.

Both the Dutch and Egyptian governments were interested in the acquisition of the IAE 33. An all-weather version with radar, two Sidewinder missiles and a Rolls Royce AJ65 Avon turbojet was also planned. It would have been a good competitor to the Sabre K, but the coup of 16 September 1955 ended production plans.

In 1947, the German aerodynamicists Hans Multhopp and Martin Winter received the request to design an experimental airplane able to fly at Mach 1.24. The project was developed at the Royal Aircraft Establishment (R.A.E.) of Farnborough, using all the aerodynamic research done for the Focke-Wulf Ta 183 as a basis. It was too advanced for its time, with a 60-degree rear swept wing and the pilot in prone position to best reduce the size of the frontal area of the fuselage, with a diameter of just 1.20 m.

A jettisonable trolley would help it for taking-off and a retractable skid system for landing, although their small fuel capacity and the high consumption rate of the turbojet advised its launching from a bomber in the same fashion than the American Bell X-1, the DFS 346 tested in the Soviet Union or the unmanned prototypes of the Miles M.52.



The project was not cancelled but evolved and converted itself into the Hawker P.1067, a predecessor of the Hawker Hunter, based in the Spec F3/48.



The British used the T-tail plane formula in the experimental airplanes and projects Avro 724, Armstrong Whitworth AW.58 and AW.169, BAC VC 10, Blackburn B.89, Bristol Type 177, 178, 183 and 188, de Havilland D.H.116, Fairey ‘Delta 1’, Gloster P.250, 259, 272, 285, 356 and F.135D, Handley Page H.P. 88 and Victor, Hawker P.1062, 1064, 1068 and 1097, Saunders-Roe P.121, 148, 149, 163 and 187, Short P.D7, Westland PJD.143 and W.37.



RAE Transonic Project Technical Data



Wings: with 60-degree rear swept at the leading edge, 42-degree at the trailing edge, 6 per cent thickness/chord ratio at the root and 10 per cent at the tip; Tail surfaces: tailplane with 60-degree rear swept at the leading edge, 46-degree at the trailing edge, tailfin with 67-degree rear swept containing the cooling system; Fuselage: with circular section, prone pilot housed in a transparent container within the air duct with ventral hatch; Landing gear: two hydraulically retractable skids; Engine: one Rolls Royce AJ65 Avon turbojet with 2,722 kg static thrust; Fuel tanks: in the wings, ahead of the main spar; Wingspan: 7.62 m; Length: 10.29 m; Height (folded skids): 2.4 m; Wing area: 17 sq. m; Estimated maximum speed: Mach 1.24 at 10,975 m; Initial climb rate: 71 m/sec;

Service ceiling: 18,290 m; Powered endurance: 30 minutes; Touchdown speed: 275 km/h.



In January 1951, Aviation Age magazine published an eye-catching picture of a Soviet fighter like the Focke-Wulf Ta 183, with a large tailfin of the same length as the fuselage and two fences in each wing panel, with the caption: The latest product of Russia’s aircraft designers, a very fast interceptor-fighter designated MiG-19. The dark painting, the red stars bordered with white, the number ‘125’ painted in the nose section and the radical aerodynamic design were a very credible set for the public, but it did not deceive the experts who ruled that an airplane with these characteristics would be useless as a weapons platform, due to excessive snaking.

In December 1951, the Flying magazine published a different version with mid-mounted wings, mid-high tail plane, the number “16” painted in the nose section and the following text: “This new, unidentified Red interceptor shows trend of Russian design. It has rocket motor installed above its axial turbojet at base of dorsal fin”.

In the book Military Aircraft of the USSR-New Types published in 1952 an “Unidentified fighter 1951” is described with three views black silhouettes and three illustrations by Bjorn Karlström depicting a tadpole-like, high-speed fighter with high-set wing and T-tail plane. The aircraft with the number “172” painted in the nose section was very similar to that of Aviation Age.

The MiG I-360 (SM-2/1) was flown on May 24, 1952. The aircraft was the prototype of the real MiG-19 and was fitted with one “Focke-Wulf style” T-tail plane.

In 1953 Aeromodeller Annual published one drawing by André Dautin depicting the “Yak-25” Soviet fighter, based in the Aviation Age picture.

In February 1954 Flying published a very detailed cutaway of the Aviation Age version.

In 1957, Flight magazine published the Aviation Age picture, including some technical data: supersonic speed, 45,000 ft. ceiling, 34 ft. wingspan, 12 ft. height and over 14,000 lb. maximum weight. According with Flight “this weird-looking red jet is apparently the latest in the MiG series to be observed, it reportedly has a rocket installed where rudder joint the fuselage bottom, for added combat speed”.

The same information was published by Italian magazines Cielo (December 1953) and Aerei d‘Oltre Cortina (Ed. Roma, 1955).



In April 1956 Avion magazine described the "MiG-19" (shown in Tushino on 1951) as a possible failure: “According to some sources entered in service by 1953, but in very limited numbers. The MiG-17 Fresco was preferred for mass-production”.

It looks like a description of the Lavochkin La-15.



In June 1953 the model maker Aurora released a 1/48 scale model plastic kit, called “Yak-25”, based on the Aviation Age version but with a nose radome inspired by the real prototype MiG-15bis (SP-1). In the 1954 and 1958 editions the name was changed to “Russian MiG-19” on the kit box art, describing it as “one of the Soviet Union´s latest and most dangerous fighters”.

The aircraft was also found its way into plastic kits from other companies and even into bubble gum cards. In 1999 the VAC-Form version was released by Harold Bickford Models as “MiG-19 Not!”

Fake rumors​

The MiG-9 was first publicly displayed at the Soviet Aviation Day air show on August 18, 1946 and in 1949 some quite accurate illustrations were published in Air Progress, Popular Mechanics, Flying and Popular Science (January 1951).



At the Tushino flypast in August 3, 1947 were displayed seven unknown fighters of the types Yak-19, Yak-23, La-150, La-156, La-160, Su-9 and Su-11.



In the 1948 edition the Yak-17 was unveiled. Acceptable illustrations of this model were published by L'Ala D'Italia in 1948 and 1951and by Popular Mechanics in January 1949.



An illustration of the Lavochkin La-7S with two wing mounted PVRD-430 ramjets and one tail mounted rocket engine like the La-7R, was published in 1948 by L'Ala D'Italia.



In January 1949 a cutaway of the Lavochkin La-7R was published by Popular Mechanics as “MiG-18”.



The Sukhoi Su-9 was described as La-8 in Flying (November 1949) and Avion (April 1956).



The La-150 was misidentified by Air Progress, in 1949, as “Single-jet fighter by Mikoyan” but the three views drawing published in the same article was surprisingly accurate.



On April 13, 1953, LIFE published the cutaway of a “Supersonic fighter”, the drawing was a very accurate reproduction of the MiG I-350 (M) powered by one Lyulka VRD-5 axial-flow turbojet.



On February 16, 1953, the American Aviation Magazine Press published a photo trick of a “Soviet” Ta 183 model with wing fences, overall aluminum paint and the number ‘72’ in the nose.

The “Soviet” Ta 183 myth continued until April 1961 with the publication of a photo trick of a MiG-15 with T-tail plane in the German magazine Flugwelt and the description: “Viel umstritten, flog in der Sowjetunion”.



By 1954 rumors from German sources indicated a Tupolev all weather fighter had entered series production, surely these reports referred to the Yakovlev Yak-25 shown in Tushino in 1955.

On April 1956 the MiG-17 SN was erroneously described in Avion magazine as a ground attack version of the Lavochkin La-17

The Soviets only allowed information to be leaked about the projects that failed, the others surprised the world.

 

[Justo Miranda]

Critics objected that the superimposed fuselage/engine configuration of the P 1101 and P 1106 projects had an excessive cross section.

The Messerschmitt design team accepted the challenge positioning the cockpit, the fuel tank and the engine one after another along the narrowest possible fuselage, locating the air intakes in the fuselage sides.

The new design, with 40-degrees sweep and 3.36 aspect ratio wing, was named P 1110. The fuselage had circular section (with 1.20 m of diameter only) and the cockpit hood, inspired in the Rennkabine of the Me 262 V9, hardly stuck 20-cm. out the fuselage.

In the January 1945 first configuration, two circular concentric air intakes, with boundary layer suction devices, were mounted 40-cm. behind the cockpit. The ‘V’ tail ensemble had 90-degrees openness. The wings were a refinement of the ‘Type A’ with highly swept root leading edge extensions. This was necessary because the airplane had too high wing load and poor maneuverability in combat at low speed.

The wind tunnel tests proved that at high speed, the shock wave generated by the wing materialized just ahead of the air intake, which could lead to an engine stop.

Messerschmitt proposed an alternative configuration with lateral air intakes mounted in front of the wing roots, but the Technisches Amt objected that the excessive length of the air ducts implied a substantial loss of power.

On February 12, Messerschmitt proposed the P 1110 Ente, a canard version with 40-degrees swept shoulder wing redesigned so as not to interfere aerodynamically with the new lateral air intakes, fitted with ‘submerged’ suction inlets to draw the air flow with the lowest possible turbulence.

The canard surfaces were positioned at the optimal distance to direct airflow to the air intakes, even at high angles of attack.

The canard configuration was expected to have excellent STOL characteristics at a time when long airstrips were scarce in the Reich.

But the Technisches Amt vetoed the project, fearing directional stability issues.

In the February 27, 1945 ‘conventional’ configuration the lateral air intakes were ‘submerged’. The new design had wooden wing with 4.29 aspect ratio and the V-tail was replaced with a conventional wooden tail unit.

The P 1110 had 14 per cent lower drag coefficient than the P 1106 and 16 per cent lower drag coefficient than the P 1101, but the boundary layer suction device used a 12 per cent of the turbojet power, the result was a maximum speed 46 mph lower than that of the P 1106.

The advanced fighter selection process continued until March 1945, in the Reserve Fighter Competition, with the intention of obtaining better aerodynamic solutions for the successor to the Heinkel He 162.

The projects proposed during the January 12 to 15 conference were Arado E 581-5 (January 8, 1945), Blohm und Voss P 212.02-02 (December 19, 1944), Focke-Wulf Ta 183 B (P 011.037a), Junkers EF 128 (January 1945) and Messerschmitt P 1111 (January 1945).



In spite of all the aerodynamic refinements tested during the P 1110 program, the problem with the turbulent air flow in the air intakes was still unresolved.

As an alternative to all these fast airplanes with high wing load, the Luftwaffe insisted on building a fighter able to fly as well as the Komet did, powered by one HeS 011 turbojet and with conventional landing gear.

The Messerschmitt answer was the P 1111 (January 15, 1945) design. It combined the reduced frontal section of the P 1110, the air intakes of the Me 262 HG III and a new 52-degrees sweep wing, with 9.16 meters wing span, based on that of the Me 163.

The projected fighter had everything: it was fast, climbed very fast and high, manoeuvred exceedingly well at low speed, had enough room to transport a lot of fuel and armament, could be built in wood and was surprisingly small and nice to look at.

However, the design contained a deathly fault: The P 1111 was very unstable at transonic speed, when the centre of pressure displaced itself rearwards and outwards from its usual location, following the main spar of the wing. The consequences had been already noticed during the July 1944 tests of the Messerschmitt Me 163 B (V18). There were violent oscillations in the vertical axis, followed by a prolonged nose-down pitch with a 60 to 80-degrees dive and total loss of control, meanwhile, the Mach number increased rapidly until it became impossible to hold the aircraft, which took over and steepened the dive to vertical.

The P 1112/S2 March 3, 1945 tried to solve the oscillations problem. It had a broader and shorter wing that was supposed to delay the centre of pressure displacing phenomena. The cockpit was integrated into the fuselage curvature and located almost 2 meters further on than in the P 1111, to avoid that the shock wave generated interfered with the air intakes. The design proved to be more stable, with 6 sq. m less of wing surface but, on the other hand, it lost its good performances at low speed and the capacity to carry most fuel in the wings.

The Northrop X-4 was specifically built to test the performances of this type of airplanes after the war. During the experiments conducted between 1949 and 1951, the American prototype proved that these wings were unstable in transonic regime (higher than 0.92 Mach) and that the migration of the centre of pressure could not be solved with the technology available at the time.

The British also built the De Havilland DH.108 experimental tailless airplane. The designer, fearing that the airplane could be unstable at low speed, built a wing of extended wing span (12 meters) instead of reducing it. The centre of pressure migration was aggravated under these conditions, producing an additional problem of aileron reversal, due to the twisting of the wing.

Alexander Lippisch also worked on the transonic oscillation problem, designing a variant of the P 1111 named P 15 (March 3, 1945). To him, the solution was to increase the wing chord, moving forward the centre of gravity and positioning the air intakes in the nose.

The P 15 combines different elements used in the Messerschmitt projects on which Lippisch had cooperated.

The 52-degrees swept wing was an adaptation from the one at the Me P 1112 S/2 (March 3, 1945) the air intakes were based on the LP 13 and Me P 1092 (July 16, 1943) whereas the tailfin and the canopy came from the LP 14 and LP 12 respectively. The air came from the turbojet through the ‘S’ shaped pipes that surrounded the cockpit, passing across the wing roots. The armament was reduced to just two MK 108/30 cannon in the wing roots and the electronic equipment would be the same than the one developed for the Messerschmitt Me 263 rocket fighter.

 

[Justo Miranda]

Post-2

 

[Justo Miranda]

Junkers EF 128

​

On December 15, 1944, the design of the most advanced German fighter developed during the war, started at Junkers-Dessau, under the leadership of Professor Heinrich Hertel.

It was a single-seat tailless fighter with a shoulder wing with 46-degrees swept at the leading edge and two vertical fins mounted at the trailing edge.

Two rectangular air intakes were placed in the fuselage sides, at very short distance from the turbojet to ensure that the short air ducts offered the least internal drag. The excess air flow was exited via a compensation chamber and a faired dorsal outlet.

Aerodynamic tests carried out at the company own wind tunnel showed strong turbulences, generated between the air scoops fairings and the lower wing surface, that could lead to an engine stop.

The first configuration EF 128 was presented to OKL during the December 19-21, 1944 meeting, but the project was rejected because the lack of sufficient longitudinal stability.

One full-scale mock-up was flight tested fixed on the top of a Junkers Ju 88 A-4 bomber, in order to study the aerodynamic behavior of air intakes and air ducts and the air bleed system under realistic conditions.

After the tests it was decided to replace the air scoops by semi-recessed air intakes with boundary layer suction inlets and a ventral fin was mounted at the rear of the fuselage.



The new configuration was submitted during the reunion of January 12-15, 1945 but, according with the Technisches Amt, the extreme design of the wings would cause structural torsion and reversal aileron forces at transonic speeds.

In the next EF 128 version, proposed in February 15, 1945, the split flaps were replaced by conventional ones and automatic slats were mounted at the wings leading edge.

On March 23, 1945, the EF 128 (February 1945) was declared the official winner of the Reserve Fighter Competition and one development contract was received by Junkers.

It was expected started the series production during the summer but all the project documentation and the mock-up were captured by Soviet forces in May.

 

[Justo Miranda]

On July 15, 1944, the Luftwaffe Technisches Amt issued the Jägernotprogramm specification, calling for an air superiority fighter powered by a 1,300 kp thrust HeS 011 A-0 turbojet, at a time when the British turbojets already generated over 2,000 kp.

In November, some ground tests carried out with the Messerschmitt Me 262 W.Nr.130015, showed that the internal drag in the air ducts reduced the turbojet thrust by 45 kp for each meter in long.

The German designers were forced to imagine new aerodynamic solutions to reduce the drag coefficient in the air ducts. Twin booms and tailless configurations with short fuselage avoided the loss of thrust associated with the long tail pipe, and the long air duct used with nose air intakes was avoided by the installation of two lateral intakes with short S-shaped ducts. Unfortunately for the Germans, with this configuration the air scoops were placed in the air turbulent zone generated over the wing upper surface by the Coanda Effect, and the loss of performance was estimated between 4 per cent and 14 per cent.

To reduce the drag coefficient at high speeds the designers of the Messerschmitt P.1110 fighter employed two boundary layer suction inlets placed ahead of the lateral air scoops. The turbulent air was sucked by means of a special extractor fan.

The Germans were extremely interested in the research by Henri M. Coanda, the Romanian aeronautical engineer that discovered the Coanda Effect in 1934 and designed the Aerodina Lenticulara flying saucer in 1935. On February 15 and September 27, 1938 Coanda received two French patents about airflow acceleration over the periphery of a concave disc. On May 9, 1939 Coanda patented a new propelling device to increase the wings lift.

During the German occupation of Paris, Coanda was forced to design a 20 m of diameter aerodyne powered by twelve Jumo 004 jet engines mounted in a radial pattern with the exhaust pipes directed towards the external ring, where the Coanda Effect produced six tons of lifting power per square yard. The air sucked through sixty slots (Lüftungs) installed around the cockpit crating a lifting power derived from vacuum effect on the disc upper surface. The air passed a toroidal plenum chamber (Zentraltur-Binenanlage) from where it was sucked by the turbojets and expelled towards the thick peripheral ring. Control was achieved by differential acceleration of the engines.

In 1937, a number of scientists and engineers from the AVA-Göttingen research center started experiments with suction inlets installed in the wing of a Junkers AT. 1 light plane. During the flight tests program an efficiency of 22 per cent was obtained with a 20 hp suction device. In 1940 was achieved a lift coefficient of 5 using a 45 hp suction fan mounted in the engine of a Fieseler Storch AT.2.

Between 1941 and 1943 the Messerschmitt Bf 109 V-24 prototype was fitted with blown flaps to improve low-speed handling. By 1944 some tests were conducted at Daimler-Benz/Stuttgart with one Bf 109 G-6 fitted with a Caudron built aile soufflé and one 9,000 rpm suction-fan blower system built by AVA. But the suction at high transonic speed required a considerable amount of power.

In February 1940, the tailless jet fighter project Lippisch P 01-112 was fitted with a suction device powered by one Bramo/BMW 3302 turbojet. In April 1943, the Arado design team proposed to use the Ar 232 A-05 prototype as flying laboratory fitted with a suction boundary layer control system powered by a cold rocket Walter HWK RI-203.

All these suction devices involved cutting slots (Lüftungs) into an aircraft’s wings, but the first attempts to use multiple slots to increase the suction rate did not achieve satisfactory results. The problem of more efficient suction led the German engineers to new research into porous surfaces with small holes.

At the end of 1944, the German foamed-metallurgy conducted experiments with porous Aluminum/Iron/Bronze alloys using the superplastic-deformation/diffusion-bonding technology. The new porous material, named Luftschwamm by the Göttingen scientist, would allow to eliminate the air scoops of the transonic fighters by delaying 1/10 Mach the apparition of compressibility shockwaves. But the work was discontinued without explanation in 1945.

The mystery was finally solved in April 1963 during the Mach 0.77 tests flights performed by the Northrop X-21A, an experimental prototype fitted with a porous breathing wing with thousands of tiny slots with 0.0035-inch width. The results were doubtful practically, because the obstructions of the slots by insects, dust, rain, and other environmental anomalies.

 

[Justo Miranda]

On their quest for aerodynamic perfection, the Horten brothers designed the H IX interceptor with the mentality of a racer plane. Margins of longitudinal stability and available inner space were sacrificed to achieve a faster plane with a minimum frontal section. However, such a tight design would seriously hamper its potential for further development as a combat airplane when facing the realities of the industrial production.



This happened when the RLM ordered the Gothaer Waggonfabrik AG the manufacturing of 40 units (under the designation Ho 8-229) in May 1945. When examining the scale drawings of the project the engineers of the company found a series of deficiencies that hindered the development of future more powerful versions of the airplane.



The Ho 8-229 lacked the required inner space to install new equipment or widen the number of crew members to convert to training or night fighter versions.

The only way to achieve that without creating any protuberances on the wing surface consisted of enlarging the nose. This solution affected the longitudinal stability and overloaded the nose oleo-leg, already in the frontier of its structural resistance. The air intakes operation was also disturbed by the turbulence generated by the new frontal configuration. The Ho 229 V6 found insurmountable difficulties to integrate the new parabolic antennae radars “Berlin N-3” and “Bremen O”



There was also the structural problem of the central section of the wing. This had been designed to house two BMW 003 A-1 engines with a diameter of 69 cm. When it was decided to install the new Jumo 004 B engines with 80 cm. of diameter, the limit of the design was reached. It could not be modified again to house the future HeS 011 of 108 cm. To that purpose, it would have been required to redesign the central section of the wing and to perform a new series of aerodynamic tests for which no time was left.



In January 1945, the design team of the Gothaer Waggonfabrik AG, led by Dr. Ing. Hünerjäger proposed the construction of the P.60 to the RLM. It was a project for a high-altitude interceptor that used the same manufacturing methods than the Ho 8-229 but without some of its structural and aerodynamic limitations. The new model could use any type of German turbojet either in service or in project. It was therefore decided to install them in the outer part of the wing in dorsal and ventral position, along the centreline, thus leaving room inside for fuel and equipment.



The pilot canopy was removed to counterbalance the increase of drag produced by the engines. The two members of the crew (in prone position) were located in a pressurised and armoured container in the forward area of the wing central section. It was considered at the time that the prone position allowed the pilot to stand high G values during the combat manoeuvres. A symmetrical profile wing with an increased sweep compared to the one in the Ho 8-229 (58º/50º at the leading edge) was also adopted.



To cure stall at landing the leading edge was fitted with hydraulically activated slats. It also had conventional flaps in the ventral side of the wing central section. They were installed with a 15º forward sweep and could also act as airbrakes.



There were three types of control surfaces:



Elevators - located in the inner trailing edge and provided with auxiliary trim tabs

Ailerons - located in the outer trailing edge with internally balanced control flaps.

Drag rudders - designed to avoid an excessive physical effort from the pilot during the manoeuvring at high speed. They were installed by pairs in the inner wingtips with a 18º slope in relation to the centreline.



They twisted vertically over an axis, like the blades in a pair of scissors, sticking out from above and under the wing surface. The resulting drag delayed a wingtip in relation to the other (remaining in smooth configuration) thus achieving a very accurate directional control.



For small corrections of path (for example to aim the guns) only the tips, with 20º slope, jutted out. The 45º was used for bigger adjustments (for example to neutralise the cross wing effect when landing) and the 90º only during the combat manoeuvres. The system defaulted to 0º/zero drag when the pilot pressure over the controls stopped. The new distribution of weights made the oleo-leg stands just a 15% out of the total (against the 45% in the Ho 8-229) allowing an asymmetrical position.



The armament was to be of four MK 108 guns for the “Höhenjäger” version, two MK 103 for the “Zerstörer” version and two MK 108 and two RB 50/18 cameras for the “Aufklärer” version. It has also been planned to increase the ceiling and climb rate of the “Höhenjäger” with the installation of a bifuel HWK 509 B rocket in the space located between the engines. This version would have been denominated Gotha P.60 A/R.



There were many critics during the life of the project for the difficulties of the crew to abandon the machine through the ventral hatch without being sucked in by the air intake of the lower engine. The same problem also existed in case of landing with the undercarriage in a folded position.



The pressurisation of the cockpit made the installation of another hatch in dorsal position difficult and it did not eliminate the risk during bail-out. A solution (also adopted in the Arado E-583) consisted of installing both engines in ventral position and the access hatch in dorsal position. This version was denominated Gotha P.60 A-2. The configuration did not remain because it diminished the rate of roll in combat and further versions were to have ejector seats installed.

 

[Dilandu]

With more than 75 years of hindsight - what other ideas can we rule out? Which aircraft might have gotten off the ground?

Basically the mistakes were systematical. German engineering degraded under Nazi very quickly. While Germany have excellent pool of engineers initially, they were put into conditions that promoted utter lack of cooperation, unhealthy competition and constant infighting between groups. Engineering collectives were often subjected to quasi-military discipline, in which only the opinion of higher ranks - usually political figures, rather than specialists - mattered. And the more war dragged on, the worse situation became, with lack of resources, the constant blame-shifting and haphazard organization (the very best example is one aircraft factory, that didn't produce a single military aircraft during the late years of war - despite being intact - because Luftwaffe leadership constantly changes it mind about what kind of aircraft they wanted to produce here, and factory constantly being in transition).

To make the bad situation worse for German engineers, the whole Nazi regime was anti-intellectual and anti-scientific. Nazi dismissed the scientific method and research, instead promoting the "genius insight of the true Ubermench". So basically the more complex and bombastic some idea was, the greater chance that Nazi leadership fell for it - no matter how unrealistic or impractical it was.

That's why I personally consider all those "Luft'46" speculations as absolutely unfounded in reality. Even if Germany somehow managed to stretch its agony to 1946, the best they could design by then would be unworkable prototypes and inefficient modernizations of old desighs. A tank industry is the good approximation; even in 1945, Germany have absolutely nothing new anywhere close to the production. Their main tanks was still an ancient Pz.IV, the "Panther" was supposed to get only a marginal turret refit (there were no weight reserves to, say, install more powerful cannon), and "Tiger II", no matter how inadequate it was against IS-2 and M26, was still in production because there were no alternative to it.

 

[HoHun]

Hi,

While Germany have excellent pool of engineers initially

My impression is that their pool of excellent engineers was so small that even before the war began, they complained about the lack of qualified personnel.

That's why I personally consider all those "Luft'46" speculations as absolutely unfounded in reality.

Well, I would put the emphasis a bit differently: Whatever new aircraft was a sketch in '45 would not have appeared over the front in '46 because lead times were several years even by the admission of the Germans, and their estimates were usually optimistic anyway.

The whole idea that complex technology could be rushed in my opinion doesn't hold true, though the Germans for the ideological reasons you mentioned probably bought into it.

An interesting book in that regard is Pohl's (of Ju 87 fame) "Professor Junkers nannte es die Fliege", in which he outlines how the complexity of aviation projects grew exponentially over time. I believe that's one even reason someone like Milch, who had a lot of industry experience, failed in his procurement activities - mabe his attempts to accelerate programs would have worked for the respective previous generation of aircraft, but each subsequent generation was more complex and actually would have required more time, not less.

Regards,

Henning (HoHun)

 

[Scott Kenny]

Well, I would put the emphasis a bit differently: Whatever new aircraft was a sketch in '45 would not have appeared over the front in '46 because lead times were several years even by the admission of the Germans, and their estimates were usually optimistic anyway.

I think the best the US ever did was 6 months from design on paper to first flight, and more like 18 months average from paper to squadron service.

But that was also with Kelly Johnson, Super Genius(tm), leading the project.

 

[Justo Miranda]

It is an accepted fact nowadays that the Allied designers never understood the true

causes of the compressibility phenomenon. At the end of the war – when they had

access to the research conducted by the Germans on the areas of swept wings, the

transonic flux, the Mach critical number of the air intakes with an air-flow separator

for the boundary layer – the cultural shock was similar to that produced in the

Newtonian world with the introduction of the relativistic physics.

The difficulty in understanding these problems during the 1940s was due to the

lack of tunnels for testing aerodynamic designs with supersonic capabilities. The

only way of studying the supersonic performance of a scale model was to install it

over the wing of a fast airplane and film it during a high speed dive. Doing so, the

air reached local supersonic speed over the wing, but the airplane did not enter into

the uncontrolled phase of the flight – something similar to the few seconds effect

of zero gravity that astronauts experience aboard a fast plane in a parabolic flight

during training.

This type of research was dangerous and difficult to perform, producing results that

were either distorted by the vibrations of the carrier plane, or by unclear films, due to

the loss of transparency of the air caused by the turbulence.

The jump seemed too big, however. The engineers never liked to face several innova-

tions within the same project. It was therefore inevitable that some transition models

appeared partially based on what had been done up to that point.

Some variants of conventional aircraft were designed with a jet engine replacing the

piston engine (Yakovlev Yak-15, Lavochkin La 174 Tk). Others had the solid nose housing

the armament and two jet engines hanging under the wings (Hawker P.1048, Sukhoi

Su-9).

In other cases, the conventional engine was retained and a turbojet, or a just a

burner, was installed at the tail, to increase the performance (Ryan FR-1 Fireball,

Mikoyan I-250/N, Sukhoi Su-5, Vultee XP-81).

Some fighters were designed with a pusher airscrew using either the twin boom

configuration and straight wing (Gloster P 18/37, SAAB J21a, De Schelde S.21, Vultee

XP-54) or arrowed wings with empennages mounted over them.

To avoid length instability, some of them had a Canard-type empennage on the nose

(Curtiss XP-55 Ascender) although the most advanced ones (Northrop XP-56) did not

use them. These two American aircraft reached the flying stage, benefitting from the

manufacturer’s wide experience in the design of flying wings. Control was achieved by

means of vertical tailfins and rudder control aero-boost ducts on the wingtips.

And meanwhile, what were the Germans doing?

They had their own problems, of supply, caused by the naval blockade.

German industry was not able to produce the specially heat and stress-resistant

metallic alloys that were required. They lacked metals like the chromium and

molybdenum that were essential to harden the steel. Germany had exhausted their

stocks and could not import them during the war, as also happened with rubber

and oil.

The chemists produced silicones to replace the rubber and made synthetic oil of low

quality from coal, but the ceramic materials for the compressor blades of the turbojets

would not be ready on time and everyone knew it.

The lack of oil suffered by Germany during the last year of the war induced scientists

and engineers to experiment with alternative fuels.

The most refined gasoline was used for conventional piston engines. The BMW 003

turbojets worked with B.4 (87 octane petrol). The J2 and K1 burnt by the Jumo 004 and

Heinkel HeS 011 turbojets were heavy kerosene. The Argus pulsejet of the V-1 worked

with crude oil. The Peenemünde engineers designed a V-2 that worked with diesel

oil and S-Stoff. Dr Pabst, from the Gas Dynamics section of the Focke-Wulf Company,

suggested that the ramjets of the future Triebflügel fighter burn even less volatile fuels,

such as pitch oil or lignite tar. To that end, they had to design a compact evaporating

plant that could be installed onboard.

This situation particularly affected the conventional piston engines. The poor

ratings of the 87 octane B4 fuel and the poor quality of Schmierstoff lubricant, which

obliged engines to be run at high revolutions to deliver the required horsepower, were

the cause of numerous problems, while deficient Kühlstoff (50 per cent glycol, 50 per

cent water) cooling, vibration fractures and disintegration of bearings, due to shortage

of tin during its manufacturing, caused corrosion and piston seizure.

To avoid these deficiencies, some engines were redesigned with bigger cylinders and

twin (three-speed) superchargers, due to the poor performance (just thirty minutes)

of the one-stage superchargers of first generation.

Attempts were also made to improve performance using two new power boost

injection systems, the GM-1 (liquid nitrous oxide) for altitudes over 10,000 meters and

the MW-50 (50 per cent methanol, 49.5 per cent water and 0.5 per cent Schutzöl 39

anticorrosion fluid) for emergency power boost at medium altitude.

In spite of all these issues, the reliability of the new BMW 003 and Jumo 004

turbojets, and the HWK 109 rocket engine was so low that the Oberkommando

der Luftwaffe allowed the development of some piston engines to continue until

February 1945.

As NASA did in the 1960s, the German aeronautical industry was forced to compen-

sate the lack of power of their engines with high technology solutions – in the 1960s it

was microelectronics to save weight, in the 1940s, it was aerodynamics.

The research sites of the Luftwaffe were the most magnificent and fully-equipped

that the world had ever seen. The most important was the Luftfahrtforschungsanstalt

Herman Göring (LFA) located near Braunschweig. By the end of the war, the LFA

had five wind tunnels (two of them were supersonic for 1.8 Mach and 4 Mach), a low

pressure tunnel for armament testing at high altitude (0.02 atmosphere), and a 10 G

centrifugal machine to simulate combat maneuvers. In the LFA, Dr Zobel used Zeiss

interferometers and high-speed moving pictures to measure the pressure distribution

around airfoils in the wind tunnels at supersonic speed, and Dr Buseman developed

the swept-wing theory for high speed flight.

In Stuttgart, the Luftfahrtforschungsanstalt Graf Zeppelin LGZ) was equipped with six wind tunnels and dedicated to subsonic ballistics.

In Kochel, the Wasserbau Versuchsanstalt Kochelsee (WVA) had a 4.4 Mach wind

tunnel dedicated to the study of the aerodynamics of the A4 rockets.

The Technische Akademie der Luftwaffe (TAL) in Berlin-Gatow, developed a system to

study the shockwaves using the Röntgenblitz (flash radiographic device).

In Berlin, the Deutsche Versuchsanstalt für Luftfahrt (DVL) was an organization

tasked with researching the security of military and civil airplanes while in flight. They

developed the area rule theory and the boundary-layer fences.

The Luftfahrt Forschungsanstalt München (LFM) located in Munich, was dedicated

to aeronautical medicine.

In Göttingen, the Aerodynamische Versuchsantalt für Segelflug (DFS) studied

gliders and rocket propelled airplanes.

In Stuttgart, the Institut für Kraftfahrtzeuge und Flugmotoren (FKFS) specialised in

aircraft engines.

The Flugfunk Forschungsanstalt (FFA) dedicated itself to electronics in

Oberpfaffenhofen.

And there also were the organizations of theoretical scientists, DMW, ZWB, LGL and

RFR, that coordinated the data coming from all the other research centers.

By the end of the war, a wind tunnel with a diameter of 3.5 meters and capacity for

10 Mach was being built in Kochel. Another of 8 meters and 1 Mach, with the capacity

for real size models, was also being built in Otztal.

The theoretical studies about the compressibility were finished by 1941 and there

were five different programs to build several types of supersonic airplanes running by

the end of the war.

It is interesting to follow the evolution of the German piston fighters as they

were incorporating into their design the aerodynamic refinements recommended

by the LFA: in the Focke Wulf fighter with Jumo 222, of 22 October 1942, with the

propeller still positioned on the nose, but the engine on the center of the fuselage

and the wing moderately swept in the leading edge only; the Blohm un Voss P.192.01

of February 1944, the propeller positioned behind the cockpit; the Daimler Benz

Hochleistungsflugzeug with DB 609 of 5 March 1942, with the propeller back to the

mid of the fuselage. The Blohm und Voss P.193, of February 1944, with the engine still

in the central section of the fuselage while the propeller is installed behind the tail

surfaces. The Dornier P.252/3, of March 1945, with propellers bent backwards as if

trying to leave the airplane, in an effort to reduce the drag

The evolution of wings and tail surfaces shows similar change, gradually bending

towards the rear of the airplane, while the engine was installed at each new stage in a

position more towards the rear.

The radiators were moved to inside the airplane, receiving the refrigeration air

through the lateral air intakes located at the wing roots, in the Dornier P.247 and Focke-

Wulf Hochleistungsjäger of March 1945. By the end of the war, we see the shape of

these fighters practically the same as that of the postwar jets. All that remained was the

small step of replacing the piston engine with a turbojet and removing the radiators.

Actually, there was never an explosive mutation between the Bf 109 of the early war

and the Me P.1110 of January 1945. The designers created a whole series of intermediate steps, following the conservative principles of good engineering.



During the last months of 1942, the balance of military power began to swing in favor of the Allies. The Axis was then forced to change their ‘conquer and consolidate’ strategy into another of ‘defense of metropolitan territory’. The industrial reorganization derived from this sudden change of political objectives proved to be of such magnitude that Germany could only partially comply with it. They made it happen by burying entire factories under armored tunnels, scattering industrial plants to make any enemy bombardment plants more difficult, developing new chemical technologies to compensate for the lack of raw materials, such as rubber and oil, and exploring all possible directions of physics, hoping to find alternative industrial procedures, direction systems, new engineering materials, or the final weapon.

Geographical imperatives forced the Allies to depend on aviation to ‘take the war’ to German metropolitan territory. Although bombing raids did little damage to the Reich industry, they were devastating for the population. For this reason, top priority was given to anti-aircraft defense: artillery, missiles, radar, and high-performance fighters.

And so was how German scientists and engineers, working under high pressure and having the right motivation and resources, created a huge range of unique projects in the history of aeronautical technology, both in terms of their variety and ingenuity of design and in the limited human resources and short time (five years) at their disposal, to produce such amazing scientific and technological achievements.

Nowadays, engineers’ fantasy is heavily determined by such conservative terms as profit or safety, all very reasonable in peaceful times. Exotic ideas that are not let down in the computer may be eliminated in the wind tunnel. However, their German colleagues of 1943 had nothing to lose: they tested everything and succeeded many times, as confirmed by the winning powers in post-war years.

 

[Jason Dykstra (Wyvern)]

The Ju 278 would've likely been unstable due to it's forward-swept wing, it would take until the advent of computers to iron out those kinks for the most part.

Any of the delta wing designs would've likely not been all that successful due to lack of area-ruling on them as well.

The Triebflugel was a non-starter.......

 

[Scott Kenny]

The Ju 278 would've likely been unstable due to it's forward-swept wing, it would take until the advent of computers to iron out those kinks for the most part.

Any of the delta wing designs would've likely not been all that successful due to lack of area-ruling on them as well.

The Triebflugel was a non-starter.......

Forward-swept wings are NOT inherently unstable.

You can make a paper airplane with FSW, they fly just fine.

 

[Justo Miranda]

Until the mid-1930s, the interest of designers in forward swept wings consisted in their ability to delay stall at low speed and high angles of attack. Low speed controllability assured full aileron control until total loss of lift, and the wingtips remained unstalled to high angles of attack. In 1921, Willy Messerschmitt built the S.9 glider to study the behaviour of this type of wings and in 1936 Alexander Lippisch used the DFS 42 Kormoran for the same purpose.



The appearance of turbojets during the 40s allowed the design of airplanes capable of flying at Mach 0.7, although only Germany had carried out theoretical studies on the behaviour of swept wings at high speeds. In 1942, the Dipl.-Ing. Hans Wocke, who carried out aerodynamic studies for the firm Junkers, concluded that the forward-swept wings generated less negative pressure on their upper surface and helped delay shock-wave formation to higher subsonic Mach numbers. In this type of wings, the aircraft drift towards the wing root and does not affect wingtips making the use of leading-edge slots unnecessary.



Unfortunately for the Germans, the scale models wind tunnel tests carried out in 1942 did not reveal the existence of two dangerous defects that would prevent their use in high speed fighters. Aircrafts with forward-swept wings suffered a pronounced tendency to Dutch roll during a turn with heavy g's loads. But much more serious was the appearance of aeroelastic divergence phenomena. When the dynamic pressure is greater than the structural elastic restoring forces, a change in lift caused by the wing deformation exceeds the structural limits and the wing fails. This phenomenon has limited the use of forward sweep to angles less than 15 degrees in the construction of the prototype Ju 287 bomber in Germany, the Cornelius XFG-1 glider in the USA and Romeo Ro.57 heavy fighter in Italy. None of these aircraft exceeded 550 kph.



Above a certain speed and degrees of forward sweep, the wing bent and twisted its leading-edge up. Increased forward sweep angle requires higher strength to resist the twisting and to delay the divergence phenomena. The wing needs to be extremely stiff, but the technology of the time and the available materials were inadequate to build such a wing. All-metall wings are effectively limited to 15 degrees, but a high-performance fighter requires a much greater degree of forward-swept.



After knowing the results of vibration tests carried out with the wing of a Ju 287 in July 1944 and the flight behaviour of the prototype Ju 287 V1, the OKL ordered the cancellation of two projects with forward-swept wings: Blohm und Voss P. 209-02 and Heinkel He 162 C (Oct 23-44) as well as the construction of the prototypes Ju 287 V3 and Ju 287 V4. Following the war, the state-of-art on materials technology was unable to resolve the wing rigidity problem and the forward-swept versions of the North American P-51, Bell XS-1, Douglas D-558-I and Convair XB- 53 did not come to be built.



The Soviets did not have much success with the information captured to the Germans in the archives of the DVL Institut. In 1948, they limited themselves to studying the aerodynamic behaviour of the forward-swept wings with the rocket research airplane Tsybin IL-3 up to 0.95 Mach. Until the appearance in the 1970s of the advanced composite structures Boron-Graphite, matrixed into epoxy resins, it was not possible to achieve sufficient stiffness to control the aeroelastic divergence at supersonic speeds.

 

[Scott Kenny]

Until the appearance in the 1970s of the advanced composite structures Boron-Graphite, matrixed into epoxy resins, it was not possible to achieve sufficient stiffness to control the aeroelastic divergence at supersonic speeds.

And even then, it required special construction to change how the wing on the X-29 flexed.

The X-29 wing is made so that instead of the leading edge twisting upwards and increasing angle of attack, the wingtips curl upwards but stay relatively flat to the airflow. Picture the wingtips becoming winglets.​

 

[Basil]

@Justo Miranda
With reference to a number of details in your comments above - are you sure you are staying with all your comments and sketches on the historical-accurate side? If not - you know there are other suitable threads in this forum.

 

[Justo Miranda]

@Justo Miranda
With reference to a number of details in your comments above - are you sure you are staying with all your comments and sketches on the historical-accurate side? If not - you know there are other suitable threads in this forum.

I am very comfortable in this forum where everyone can freely express their opinions as long as they respect those of others, if those in charge of maintaining order agree with my way of expressing myself I see no reason to seriously consider their objections. If you don't like what I do you can always stop reading my posts, I do it civilly with the opinions of other members who do not act with proper courtesy.

 

[Antonio]

@Basil
Please avoid personal attack/offensive comments

 

[Basil]

No offense intended.
Since most contributors to this high-quality forum strive for historical accuracy, artistic deviations or personal interpretations should be marked as such or placed in the appropriate thread. Ultimately, however, this is of course a matter for the responsible moderators to decide.