British WW2 Multi-role Plane

Tony Williams

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I enjoy playing with alternative histories with the emphasis on military technology, and there are several items about this on my website (I may start other threads on some of them). These are mostly to do with guns and ammunition, but this one I came up with in answer to the question: if there was one British combat plane which you could design for service throughout WW2, what would the specification be? See: http://www.quarry.nildram.co.uk/WW2plane.htm for my take on this.
 
Training requirements don't much favor the all in one concept of carrier aircraft. At least not with WW2 technology and above all WW2 standards for replacement pilots. Fuel consumption might be an issue as well on the armored deck RN ships, they didn't hold much gas. This was a very serious problem once deck parks were introduced.


Multirole planes are a fun idea, but in the end twin engines in WW2 effectively meant building half as many aircraft that required twice as much maintenance which tends to undermine the possible advantages. You'll also never match the agility of enemy single engine fighters when flying in the escort role. This made the P-38 largely a failure in Europe, it did much better against Japanese fighters which were too underpowered to catch it. Plus Japanese pilot quality was already collapsing by the time serious numbers entered combat.


Not a bad thought exercise though, I just think its not surprising that no such plane existed.
 
Yes, I'd been thinking about the training issue for the carrier pilots. The simple answer would be to have more than one pilot per plane, one trained as a fighter pilot, another as a bomber, since it's much easier to find space for another body than for another plane.

The extra cost and maintenance of a twin-engined plane is a fair point, but wartime experience didn't stop them continuing to be developed. The DH Hornet and F7F Tigercat both entered service too late for the war, but were outstanding aircraft which saw service on carriers afterwards.

Also, the extra power of a twin would enable the proposed plane to perform tasks which contemporary single-engined planes could not.
 
Sea Skimmer said:
I just think its not surprising that no such plane existed.
The Mosquito FB Mk VI came close.
 
Tony Williams said:
Yes, I'd been thinking about the training issue for the carrier pilots. The simple answer would be to have more than one pilot per plane, one trained as a fighter pilot, another as a bomber, since it's much easier to find space for another body than for another plane.


That really doesn't work, the pilots must fly constantly to remain skilled, having them fly half as much doesn't exactly help. The USN for example found a serious and rapid reduction for example, in the effectiveness of its bomber pilots at hitting moving ships after they'd been tasked to primarily bombing shore targets in the Pacific. You can find space for the pilot sure, but I doubt the RN ever had much of a surplus of qualified pilots. Of course you must also train and find space for the extra mechanics. Certainly possible, but its another cost.



The extra cost and maintenance of a twin-engined plane is a fair point, but wartime experience didn't stop them continuing to be developed. The DH Hornet and F7F Tigercat both entered service too late for the war, but were outstanding aircraft which saw service on carriers afterwards.


Only a handful of the final production F7Fs were ever cleared for carrier use. The majority of those built proved too hot and dangerous and ended up in USMC hands on land. That's why it missed war service and not the greatest endorsement. The Sea Hornet did work, but as I recall it was supplanted rapidly by the much more heavily produced single engine Sea Fury. Certainly it did not lead to the conversion of the RN over to twin engine multi role aircraft. Indeed the RN would go on to specify dedicated fighter and bomber types for as long as it was allowed to design its own aircraft, even though it was well aware that its carriers were small and thus in greater need of such aircraft then the the US navy ever was.

Also, the extra power of a twin would enable the proposed plane to perform tasks which contemporary single-engined planes could not.


On a one for one basis that may be true, but the importance of such missions which would be primarily bombing and reconnaissance, and the overall advantage compared to a mixed force is open to debate. On the other side of the coin some incredibly potent single engine strike planes were possible, such as the AM Mauler and XTB2D Skypirate. The former could carry three and the later four torpedoes, while a Sea Hornet cannot carry weapons over 1,000lb which is a serious disadvantage in the anti ship role.


Indeed the Sea Hornet offensive payload is inferior to that of the later models of F4U Corsair which had wings rated for 4,000lb of bombs. Limitations like this are part of the reason why a plane like the Sea Hornet could have such high performance, it was just lightly built. The F7F I might add was similar, max payload was 2,000lb, though it did have a hard point rated for a torpedo.
 
Sea Skimmer said:
Tony Williams said:
Also, the extra power of a twin would enable the proposed plane to perform tasks which contemporary single-engined planes could not.

On a one for one basis that may be true, but the importance of such missions which would be primarily bombing and reconnaissance, and the overall advantage compared to a mixed force is open to debate. On the other side of the coin some incredibly potent single engine strike planes were possible, such as the AM Mauler and XTB2D Skypirate. The former could carry three and the later four torpedoes, while a Sea Hornet cannot carry weapons over 1,000lb which is a serious disadvantage in the anti ship role.

Bear in mind the purpose of this thought exercise, which is not to identify which mix of planes might have been best for specific roles at the end of the war, but which single additional plane might have been more generally useful to the British throughout the war (in full squadron service by early 1940). The emphasis in the discussion so far has been on the carrier version, but that is only one of the variants proposed.
 
As I said in the first place, not a bad thought exercise, but it was never enough to just design a plane when it came the actual service. On land I'm not really sure what such a plane is really supposed to do that the Mosquito already didn't.
 
I think the point is, the plane being proposed was to be in service before or at the outbreak of war whereas the Mosquito didn't appear until later.

Its a bit like asking why did they bother with the Beaufighter when there was the Mosquito? Both appeared at a similar time. Might it not have been a case of not putting all your eggs in the one basket? The Beaufighter used existing design and manufacturing capacity, the Mosquito non-strategic materials and labour. It wasn't known how useful either was going to be when they were proposed.
 
OK, I'll bite to suggest something a little bit out of the ordinary.

What if, after the failure of the Boulton Paul Defiant in its designed role as a turret fighter, the RAF had taken a long hard look at the 1000+ airframes on hand to say, can we salvage this and make it into something useful? If the spirit of innovation and simplicity of the Miles M.20 emergency fighter had been applied to redesign and rebuild the existing airframes, the result might have been something quite different, a Defiant Attacker:

--Drop the Merlin in favor of lighter and more rugged radial:
--Lose the retractable gear in favor of lighter faired fixed gear;
--Add forward-firing guns--a pair of 20mm cannon?--in wing "plugs" between the center section and outer panels for a little more wing area;
--Add armor for the crew and critical systems and external bomb racks.

Now instead of a mediocre fighter you have a fairly fast and maneuverable single-engine light bomber or ground attack aircraft that can turn and bite an unwary opponent. Maybe later the the quad .303 turret is replaced by a pair of .50 cal or even a 20mm cannon to make it tougher to shoot down. In all theaters, the tough Defiant Attackers become specialized ground attackers, a British counterpart to the Ilyushin Il-2 Shturmovik. In North Africa, they carry the 40mm Vickers guns and leave the Hurricanes to fly top cover. For night fighter use, maybe the rear turret is deleted altogether in favor of radar equipment and "schrage musik" 20mm cannons firing upwards. Perhaps the FAA takes on the Defiant Attackers as high performance short-range coastal ASW aircraft, and later a navalized version with bombs and rocket projectiles sees action from carriers.

All pure fiction, of course, but fun to think about.

Cheers,

Matthew
 
I agree that useful changes might have been made to the existing Defiants, but I don't think that changing the engine would have beeen one of them - too radical and costly a change, which would have required a major redesign and rebuild. Removing the turret would have been simpler and saved a lot of weight (620 lbs) and drag. That would have enabled various options:

1. A night fighter, with a second crewman retained as a radar operator and with a pair of 20mm Hispanos in the wings and another pair in a Schräge Musik installation behind the cockpit. Total weight of the four cannon would have been about 440 lbs so still lighter overall, and the balance would be more or less maintained.

2. A fighter-bomber, with the turret replaced by a much simpler flexible mounting for a pair of .303, extra armour, a pair of wing-mounted Hispanos (or Vickers S) and a a useful bomb load. Weight distribution may have been more of a problem, since the turret was mounted well behind the centre of lift.
 
Apart from not being available in 1940, the Mosquito fits the bill perfectly.

Long-range fighter: the FB VI could hold its own against the Fw190 in a day fight. The night fighter NF II and high altitude F XV were in use in 1942.
Ground attack: apart from the rocket armed FB VI, there was the FB XVIII 'Tsetse' with its 57mm anti-tank gun.
Carrier multi-role plane: a carrier-capable variant was built, flown succesfully in 1945, the TR 33.
I remember reading somewhere people proposed replacing Lancasters by Mosquitoes as the latter were lighter on crew, more survivable, cheaper to build while delivering up to 4,000 lbs of bombs.

The Mosquito had one major drawback. From your website:
...the DH Mosquito (too big, not available in 1940 and too much in demand for other roles)...
Of the FB VI alone, 2,298 were built. Too much in demand, so not enough. Any multi-role aircraft with comparable performance would find itself in the same position.

I don't know about it being too big. You needed two Merlins to power it, which could also be used for two Mustangs. Other than that, it was brilliant.
 
I would suggest that instead of rebuilding the Defiant, it would be better to scrap them and use the materials to build something more useful. The engines could be reused while the turrets could be used in medium/heavy bombs. The considerable amount of materials used to build and form the stores holdings to maintain the Defiant force would have been better employed elsewhere. Remanufacture would consume nearly as much labour and time as building something from scratch. The Defiant was failed design and I suspect that adding 20mm cannons to the light-weight wing structure might be beyond its capabilities, particularly as far outboard as would be required to clear the undercarriage. Better to be Pound wise rather than Penny foolish, I would suggest.
 
Kadija_Man said:
I would suggest that instead of rebuilding the Defiant, it would be better to scrap them and use the materials to build something more useful.

You're probably right, but it wouldn't be so much fun to discuss ;D
 
Arjen said:
Apart from not being available in 1940, the Mosquito fits the bill perfectly.

The Mossie was an outstanding aircraft, and my favourite of WW2. However, its size did count against it in the roles which I have outlined. For a start, even with folding wings I believe it was too big to fit in most (if not all) RN carrier lifts so could only be carried parked on deck - without room for many of them. Its size would also have made it a bigger target in the ground attack role and increased the weight of any armour added, plus the liquid-cooled engines would be more vulnerable anyway. And I can't see it being as agile as a smaller twin, or delivering the same level of performance.
 
Kadija_Man said:
Out of a matter of interest have you considered the proposed twin-engined development of the Fairy Battle?

Interesting, but with limited development potential as the item says, so not worth the effort.

Talking of twin-propeller versions of singles, I had an idea concerning the Bell P-39. That is, to have the engine driving two propellers, one on each wing, rather than one in the front. This would leave the nose clear for gun armament without the need to synchronise the .5 inch BMGs (which lost around 40% of their rate of fire when synchronised) and the propwash over the wings and flaps would also improve the lift at low speeds.

While on the subject of modifying existing designs, I have a simple proposal for the later versions of the Messerschmitt Bf 109: add a wing-root insert (maybe 0.5 metre each side) to which the usual wings would be attached. This would have three significant advantages:
1. The extra wing area would restore some of the flying qualities lost with the steady increase in weight.
2. The main undercarriage would be mounted on the outside of the new wing roots, thereby providing an extra metre of track width to improve stability on the ground.
3. A synchronised 20mm MG 151 could be fitted into each of the wing root extensions as with the Fw 190, giving a total of three 20mm cannon clustered around the centreline. This would make the cowling MGs unnecessary, allowing the cowling to be cleaned up aerodynamically.
The beauty of this proposal is that it would retain nearly all of the existing plane, just add a couple of bits.
 
There was a single seat derivative of the Defiant but it was rejected by the RAE. That was developed into the P.94 proposal with a cut-down rear fuselage and wing armament of 12x.303 or 4x20mm. Never went anywhere. I want to think that the kindest thing that can be said for the Defiant is that Boulton-Paul should instead have been contracted to open a Spitfire line; the Boulton Paul Wolverhampton facility was relatively modern so may have been able to manage a substantial production rate. That said, the type did do reasonably well as a night-fighter interim to the Beaufighter.

Then there is the Hurricane that spawned the Henley light/dive bomber and the Hotspur turret fighter- both apparently well regarded relative to the other types competing their respective requirements.
 
Didn't the Germans, Arado I think, have some paper designs for planes with engines in the fuselage, and driveshafts to wing propellers? It sounds workable in principle, but very difficult to engineer with acceptable vibrations. You'd also need some system that allows one propeller to run if the other is damaged without exploding the gearbox, otherwise the vulnerability of the plane would be pretty high.
 
JFC Fuller said:
There was a single seat derivative of the Defiant but it was rejected by the RAE. That was developed into the P.94 proposal with a cut-down rear fuselage and wing armament of 12x.303 or 4x20mm. Never went anywhere. I want to think that the kindest thing that can be said for the Defiant is that Boulton-Paul should instead have been contracted to open a Spitfire line; the Boulton Paul Wolverhampton facility was relatively modern so may have been able to manage a substantial production rate. That said, the type did do reasonably well as a night-fighter interim to the Beaufighter.

Then there is the Hurricane that spawned the Henley light/dive bomber and the Hotspur turret fighter- both apparently well regarded relative to the other types competing their respective requirements.

AIUI, The Hotspur was considered to be superior to the Defiant, however, Hawker were required to concentrate on the Hurricane, and as Boulton Paul (no hyphen) didn't have an aircraft of their own in production at the time, they got the contract...
Another factor to bear in mind was the Defiant was also designed with ease of manufacture in mind...

While on the subject of modifying existing designs, I have a simple proposal for the later versions of the Messerschmitt Bf 109: add a wing-root insert (maybe 0.5 metre each side) to which the usual wings would be attached....

Messerschmitt did exactly this when they started developing the Bf 109H high-altitude version of the the Bf 109, without the cannon...

cheers,
Robin.
 
robunos said:
AIUI, The Hotspur was considered to be superior to the Defiant, however, Hawker were required to concentrate on the Hurricane, and as Boulton Paul (no hyphen) didn't have an aircraft of their own in production at the time, they got the contract...
Another factor to bear in mind was the Defiant was also designed with ease of manufacture in mind...

That is my understanding as well, though I can not imagine the Defiant being significantly easier to manufacture than the Spitfire. I also recall that the Henley went nowhere largely due to a shortage of Merlins and propellers as much as any doctrinal changes. And lets not forget the wood and steel Albemarle. This of course raises and interesting, one of the advantages of the multiplicity of types being pursued by the RAF by the end of 1939 is that a process of Darwinism gradually resulted in the best types rising to the surface- Lancaster, Spitfire, Beaufighter, etc whilst others died because they were flawed concepts, bad designs or had their prototypes destroyed by bombing. There were also sufficient configurations around to use most of the engine types available.
 
JFC Fuller said:
though I can not imagine the Defiant being significantly easier to manufacture than the Spitfire

The wings were very difficult to build on the Spitfire but of course it was the wing which gave it the excellent performance. Obviously the turret added hugely to the complexity of the Defiant but without it such an aircraft would be much easier to build than the Spitfire thanks to the simpler structure.
 
Kadija_Man said:
Its a bit like asking why did they bother with the Beaufighter when there was the Mosquito? Both appeared at a similar time. Might it not have been a case of not putting all your eggs in the one basket? The Beaufighter used existing design and manufacturing capacity, the Mosquito non-strategic materials and labour. It wasn't known how useful either was going to be when they were proposed.

The Beaufighter was ordered long before (by WWII standards) the Mosquito was anything more than a good idea being bounced around the De Havillands design office. They were also both ordered for completely different things. The Beaufighter was to be the RAF’s cannon fighter and the Mosquito the unarmed, fast bomber. They were both expected to be very useful when proposed otherwise they wouldn’t have received orders by the RAF. The Mosquito of course was a lot more controversial but there those more visionary that knew it would be very useful. Just a shame it wasn’t more supported because it could have taken over the burden of the bombing campaign from the Lancaster and Halifax with less cost, less risk and a lot less casualties.
 
JFC Fuller said:
This of course raises and interesting, one of the advantages of the multiplicity of types being pursued by the RAF by the end of 1939 is that a process of Darwinism gradually resulted in the best types rising to the surface- Lancaster, Spitfire, Beaufighter, etc whilst others died because they were flawed concepts, bad designs or had their prototypes destroyed by bombing. There were also sufficient configurations around to use most of the engine types available.

The Spitfire, Lancaster and Mosquito were the three outstanding British aircraft of the war, but there were less-capable planes which remained in production for lack of anything better and found niche roles, such as the Hurricane which - fortunately - just remained effective as a fighter into mid-1940, then became rapidly outclassed so was relegated to ground attack (in which it proved rather vulnerable), the Beaufighter which was too big and slow as a fighter but found a useful niche as a Coastal Command strike plane, and the Typhoon which was seriously flawed as a fighter so again ended up as a mud-mover. Conversely there were some apparently very good planes which never made it, like the Martin-Baker MB 5. And we never did manage to make any decent carrier planes for the duration of the war, nor a really good ground-attack plane.

The two most useful engine types soon became the Merlin and Hercules, with others in largely unnecessary supporting roles.
 
Tony Williams said:
if there was one British combat plane which you could design for service throughout WW2, what would the specification be? See: http://www.quarry.nildram.co.uk/WW2plane.htm for my take on this.

This is very similar to the RAAF’s controversial pre-war requirement for a long range fighter. There was a lot of national politics, service politics, domestic industry politics and Empire politics caught up in this aircraft concept and it did lead to a severely disadvantaged Australian defence capability in late 1941 when it shouldn’t have been. However it is interesting from a capability discussion point of view and does align with this discussion. I’ve had some thoughts about this in the past and will share them here for this debate.

The RAAF’s director of operations and intelligence who became chief of air force at this time: Air Marshall Bill Bostock formulated a concept of a long range fighter to defend Australia because enemy (Japanese) carrier aircraft would have to be destroyed at their source (carrier) not over their targets because Australia was too big too dispersed to be covered by point defences. How of course they were going to know where the carriers were was never addressed beyond wishful thinking but this became RAAF policy so point defence, single engine fighters were not required. The long range or “interdiction fighter” was to have a navigator with radio D/F, chart table etc, and the aircraft was to be high speed with twin engines. The requirement was meet by the “Beaufort Fighter” (aka Beaufighter) which was a fit to the specification, common in parts with the Beaufort which a government owned factory was being established to build and also very timely as it was proposed by Bristol and prototypes ordered by the RAF at the same time as the RAAF interdiction fighter requirement was formulated (1938/39). Of course as we now know the Beaufighter could not successfully intercept single engine fighters and wouldn’t be available to the RAAF from UK production until 1942 and local production in 1944.

But playing with ‘what if’ what kind of fighter could meet the RAAF requirement and defeat single engine Japanese carrier fighters? Clearly with the engines available in the late 30s any long range “interdiction fighter” that could double as a strike reconnaissance aircraft had to have two of them. As was the case with the Mosquito, Beaufighter, etc. The problem of course with most twin engine designs is they lack the roll rate to be a competitive fighter. Unless you either place the engines in a row or side by side in the fuselage and either have a push pull design with two separate propellers or run both engines through a single counter rotating propeller arrangement.

The Dornier Do 335 demonstrates the potential for such a twin engine fighter to still retain high roll rate and be a competitive dog fighter. But the push pull configuration wasn’t in wide practice at the time (late 1930s). There was another configuration better known which was the Heinkel He 119 with two engines side by side in the fuselage powering a single nose propeller via gearing. But side by side engines is something you could do with a German inverted V engine for a triangle shaped fuselage. With Merlin engines such a fuselage would have the base of the triangle on top so the cockpit would have poor downwards view. Also the close coupled side by side engine configuration never worked well for heat management. But maybe you could have the two Merlins in a row with maybe one raised and the other lowered so the drive shaft of one engine could go under the other? Mount the engines amidships with a cockpit forward and a counter rotating prop in the nose and maybe you have something? Of course then where goes the wing? With a lot of stuff in the fuselage putting the wing above the body makes it easy to manage the weights and access for all the stuff. Except this makes for heavy gear if they are wing mounted thanks to extra length. Though gear could be scabbed onto the side of the fuselage to maintain up down access to the engines and propeller gearing. Which would save weight and enable the fuselage to be built separate to the wing with the two only mated up at the end of production.

There is a great image of the configurations Heinkel played with between the He 119 and He 219 online at:

http://crimso.msk.ru/Images6/AS/AS93-2/20-3.jpg

I’ve used this to come up with a stacked engine fighter concept as outlined above. A British Empire version with Merlins could be smaller but would still be a big plane compared to a single engine fighter. With the right wing design and keeping weights down (comparatively) there is no reason it couldn’t be as agile as the single engine fighters. There is plenty of space under the cockpit around the propeller gearing for guns and radiators. Of course who could build such a plane, would it be funded and would it get into service are all other points. But if it was progressed pre-war you could have a long range strike fighter with high agility and high speed. Big, loud and expensive but a 1940 F-4 Phantom would like the later day Rhino earn its keep.
 

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Tony Williams said:
And we never did manage to make any decent carrier planes for the duration of the war, nor a really good ground-attack plane.

There was an interesting article in a later Aviation Enthusiast about Boulton Paul’s naval fighters and how they lost the naval turret fighter competition to Blackburn with a naval Defiant and how this could have been the Fleet Air Arm single seat fighter of the war (sans turret of course) if it had been ordered. I think there is some discussion in this forum somewhere about this family of never built aircraft.

http://www.secretprojects.co.uk/forum/index.php/topic,8329.0.html
 
Interesting concept, Abraham. I wonder, too, what if the British Purchasing Commission of 1938 had been briefed on the Grumman XF5F-1 Skyrocket (ordered by the US Navy in June 1938) and decided to push for accelerated development of that type? A developed, Commonwealth version of the Skyrocket, say with a pair of 20mm Hispanos and four .303 Brownings, might well have had the speed, range and firepower to meet that RAAF design brief. The two-seat reconnaissance types would still have to find the Japanese fleet, of course.

4561351125_3be207e685_z.jpg


grumman_xf5f_skyrocket_usa_1940-36469.jpg


Specifications (XF5F Skyrocket)
General characteristics
Crew: 1
Length: 28 ft 9 in (8.76 m)
Wingspan: 42 ft (12.80 m)
Height: 11 ft 4 in (3.45 m)
Wing area: 303.5 ft² (28.2 m²)
Empty weight: 8,107 lb (3,600 kg)
Loaded weight: 10,138 lb (4,600 kg)
Max. takeoff weight: 10,900 lb (5450 kg)
Powerplant: 2 × Wright XR-1820-40/42 Cyclone nine cylinder radial air-cooled engine, 1,200 hp (895 kW) each
Performance
Maximum speed: 383 mph at sea level (616 km/h)
Range: 1,200 mi (1,800 km)
Service ceiling: 33,000 ft (11,000 m)
Rate of climb: 4,000 ft/min (1,220 m/min)
Armament
4 × 0.5 in (12.7 mm) machine guns
4 × 165 lb (75 kg) bombs

Source: http://en.wikipedia.org/wiki/Grumman_XF5F_Skyrocket

Abraham Gubler said:
I’ve used this to come up with a stacked engine fighter concept as outlined above. A British Empire version with Merlins could be smaller but would still be a big plane compared to a single engine fighter.
 
The complexity of Spitfire wing manufacture is notorious, however sticking a turret on the Defiant would appear to offset some of its supposed ease of production. But, as I stated earlier it apparently did reasonably well as a night-fighter; Everything has its nuance. The Typhoon being representative of this, calling it flawed seems excessive when we consider that by D-Day the RAF had 27 squadrons of the type with 2TAF operating 18 of those in the Ground Attack role and the type claimed 246 air-to-air kills. On the theme of nuance the likes of the Typhoon should also make us question the idea that the UK never developed a dedicated ground-attack aircraft; The Typhoon may have been developed as a fighter, a role in which it did not excel at anywhere above low altitude, but by the end of the war it had taken on 780lbs of armour, was operating with 12 rocket projectiles or 2 x 1,000lb bombs as maximum operational payloads, was equipped with air filters to ease operations from front-line airstrips and had a dedicated tactical reconnaissance variant. It was also trialled with 40mm cannon. Technically not designed as a ground-attack aircraft but it certainly evolved towards being one rather like the FW-190F. On the other hand we the MB.5, it certainly seems to have been considered an excellent type but by the time it flew the RAF had Griffon Spitfires, Sabre Tempests, Centaurus Tempests on the way, the DH Hornet and Vampire were already flying, the Gloster Meteor was about to be introduced, and the UK had access to the P-47&51. To a certain extent, when MAP was choosing single seat fighters to acquire in 1944 it was like a kid in a candy shop. I do agree that greater focus on both carrier and ground attack aircraft would have been helpful but this owed a lot to pre-war RAF priorities which were Bomber Command, Fighter Command and then everything else- in that order.
 
Mole said:
Interesting concept, Abraham. I wonder, too, what if the British Purchasing Commission of 1938 had been briefed on the Grumman XF5F-1 Skyrocket (ordered by the US Navy in June 1938) and decided to push for accelerated development of that type? A developed, Commonwealth version of the Skyrocket, say with a pair of 20mm Hispanos and four .303 Brownings, might well have had the speed, range and firepower to meet that RAAF design brief.

The Grumman Skyrocket is too small for the RAAF interdiction fighter. There is no weight/space margin for a navigator.

Mole said:
The two-seat reconnaissance types would still have to find the Japanese fleet, of course.

The RAAF requirement was for all interdiction fighters to have two seats so they could find their way to and back from an offshore carrier. Finding the carrier would be the job of the general reconnaissance bombers but the big problem was the gap between finding the carrier and the interdiction fighter arriving over the carrier. It was within this gap that the carrier would launch their air wing and strike their unprotected target while the RAAF’s fighters were off trying to shoot the Jap planes down out at sea. Which is of course why the RAAF should have just brought a much simpler single engine fighter. But such an aircraft didn’t fit into the Australian industry political dynamic (America vs Great Britian) being pushed by the Prime Minister at the time.
 
Ah, of course, that's certainly true. But I suppose that my defense is that the RAAF might have figured out that the two-seat fighter wasn't the way to go after all. Maybe a few lightly armed, two seat versions of the Skyrocket, adapted from a hastily-produced operational trainer, could have acted as "pathfinders" to guide the single-seaters to the target? ;-p

Abraham Gubler said:
The Grumman Skyrocket is too small for the RAAF interdiction fighter. There is no weight/space margin for a navigator.
 
Abraham Gubler said:
I’ve used this to come up with a stacked engine fighter concept as outlined above. A British Empire version with Merlins could be smaller but would still be a big plane compared to a single engine fighter. With the right wing design and keeping weights down (comparatively) there is no reason it couldn’t be as agile as the single engine fighters. There is plenty of space under the cockpit around the propeller gearing for guns and radiators. Of course who could build such a plane, would it be funded and would it get into service are all other points. But if it was progressed pre-war you could have a long range strike fighter with high agility and high speed. Big, loud and expensive but a 1940 F-4 Phantom would like the later day Rhino earn its keep.

Yes, I've wrestled with the pros and cons of various twin-engined arrangements myself. The tandem push-pull is the neatest and probably most efficient but has various disadvantages in terms of ensuring stability (the Do 335 tended to "porpoise" as I recall) and fitting guns around them - especially as the Hispano could not be synchronised. What you propose is a sort of doubled-up P-39 with extra complexity :). I instinctively feel that simplicity was a virtue in the WW2 era, since various unconventional planes (e.g. canards, flying wings) flew but none was ever successful.

For my OP proposal, the twin engines would have been as close to the centreline as possible to minimise the folded width so that the plane could fit onto our narrow carrier lifts. That would of course help with the roll rate as well. A conventional twin can also take a big anti-tank cannon on the centreline, to give it the most rigid and accurate mounting.

As with all military equipment, it's a matter of choosing the most appropriate compromises in the light of the requirements and what was feasible at the time. There is no one right answer - but quite a few wrong ones!
 
Tony Williams said:
Yes, I've wrestled with the pros and cons of various twin-engined arrangements myself. The tandem push-pull is the neatest and probably most efficient but has various disadvantages in terms of ensuring stability (the Do 335 tended to "porpoise" as I recall) and fitting guns around them - especially as the Hispano could not be synchronised.

Unsynchronisable guns can be mounted in the wings just like any other front propeller aircraft.

Tony Williams said:
What you propose is a sort of doubled-up P-39 with extra complexity . I instinctively feel that simplicity was a virtue in the WW2 era, since various unconventional planes (e.g. canards, flying wings) flew but none was ever successful.

Complexity is the price one pays to achieve an aim. In this case a low drag, high roll twin engine aircraft. Though such an arrangement is mechanical complexity via the counter rotating propeller and long drive shafts. Though the later are quite normal on a helicopter and in many ways more appropriate to a combat aircraft than long tubing for coolants from engine to displaced radiators. The aerodynamic complexity of such an arrangement is actually a lot simpler than conventional twin engines on the wings configuration.

Tony Williams said:
For my OP proposal, the twin engines would have been as close to the centreline as possible to minimise the folded width so that the plane could fit onto our narrow carrier lifts. That would of course help with the roll rate as well. A conventional twin can also take a big anti-tank cannon on the centreline, to give it the most rigid and accurate mounting.

It’s still going to roll like a pig and by placing the engines as close to the airframe as possible you have the problem of a short propeller blade, vibration on the fuselage from close propellers, aerodynamic interference from the fuselage, etc, etc. You can put the big cannon on the centreline of my proposed configuration because it only needs to fire through a gear box and the propeller hub. This is a lot easier to design than a cannon that fires through an aircraft engine. But this wouldn’t be needed for a strike fighter because front guns in the wing or synchro Brownings in the nose are good enough.
 
Tony Williams said:
Kadija_Man said:
Out of a matter of interest have you considered the proposed twin-engined development of the Fairy Battle?

Interesting, but with limited development potential as the item says, so not worth the effort.

Hindsight is a wonderful asset. How would you know if a design had "limited development potential" until it had been built and tested?

Talking of twin-propeller versions of singles, I had an idea concerning the Bell P-39. That is, to have the engine driving two propellers, one on each wing, rather than one in the front. This would leave the nose clear for gun armament without the need to synchronise the .5 inch BMGs (which lost around 40% of their rate of fire when synchronised) and the propwash over the wings and flaps would also improve the lift at low speeds.

An interesting idea. I foresee problems with the drive shafts and gearboxes. One of the proposals for what became the P-38 used a similar idea but was discarded IIRC for that very same reason. Several promising US designs were failures because of problems with extended drive shafts and gearbox issues.

While on the subject of modifying existing designs, I have a simple proposal for the later versions of the Messerschmitt Bf 109: add a wing-root insert (maybe 0.5 metre each side) to which the usual wings would be attached. This would have three significant advantages:
1. The extra wing area would restore some of the flying qualities lost with the steady increase in weight.
2. The main undercarriage would be mounted on the outside of the new wing roots, thereby providing an extra metre of track width to improve stability on the ground.
3. A synchronised 20mm MG 151 could be fitted into each of the wing root extensions as with the Fw 190, giving a total of three 20mm cannon clustered around the centreline. This would make the cowling MGs unnecessary, allowing the cowling to be cleaned up aerodynamically.
The beauty of this proposal is that it would retain nearly all of the existing plane, just add a couple of bits.

An interesting idea. Having recently examined the Bf109G which hangs in the Australian War Memorial it's obvious that the cowling by then had real problems, not only from the design but poor workmanship. I estimated it was possible to fit hand in the joint at the rear. Perhaps it had a secondary cooling outlet purpose?

The problem with increasing the winspan of any aircraft without compensating by increasing the length to match invariable removes the harmony of the controls. The Bf109 was a handful by the F model and only got increasingly worse after that. I wonder what your proposal would have done to handling? One of its big benefits though would have been to remove those horrible underwing gondolas for the 20mm cannon and moved the weight inwards, perhaps improving roll rate.
 
Abraham Gubler said:
Unsynchronisable guns can be mounted in the wings just like any other front propeller aircraft.

Yes, but that is relatively inefficient compared with concentrating the cannon in the nose (it also adds weight out on the wings - roll rate....). There were also problems with fine-tuning all Hispano wing installations, even the big Blackburn Firebrand, because it was intended for a much more rigid mounting.

Complexity is the price one pays to achieve an aim. In this case a low drag, high roll twin engine aircraft. Though such an arrangement is mechanical complexity via the counter rotating propeller and long drive shafts. Though the later are quite normal on a helicopter and in many ways more appropriate to a combat aircraft than long tubing for coolants from engine to displaced radiators. The aerodynamic complexity of such an arrangement is actually a lot simpler than conventional twin engines on the wings configuration.

The problem with long shafts taking lots of power is that they have to be very rigid, which among other things means they have to be firmly supported by bearings, and the supporting structure for the bearings has to be very rigid, which adds weight. You're also adding weight with the gearbox (which also has to be rigidly mounted). So there is a weight penalty with a layout like this. Also, while the layout should provide a fast roll rate, I suspect the distribution of weight along much of the length of the plane would make elevator response rather slow.
 
Kadija_Man said:
How would you know if a design had "limited development potential" until it had been built and tested?

You can get a good idea from looking at the aerodynamics and structural design. The Battle seems to have been a rather old-fashioned design, not built for very high speeds.

The problem with increasing the winspan of any aircraft without compensating by increasing the length to match invariable removes the harmony of the controls. The Bf109 was a handful by the F model and only got increasingly worse after that. I wonder what your proposal would have done to handling? One of its big benefits though would have been to remove those horrible underwing gondolas for the 20mm cannon and moved the weight inwards, perhaps improving roll rate.

Well, I think that the control harmony was pretty well shot by all the weight increases anyway. By all accounts the later 109s were pigs to fly. Adding more wing area should have helped.
 
You can get a good idea from looking at the aerodynamics and structural design. The Battle seems to have been a rather old-fashioned design, not built for very high speeds.

The type was a victim of its timing, probably seemed like a great idea when it was conceived in 1932- much the same as the Defiant, but fighter technology and fire-power moved so quickly it was soon obsolete. Reminds me of the AW Whitley and DH Hendon; they seemed space age compared to what they were replacing but were obsolete themselves within 4 years of their first flight.

The Battle did at least give us the wonderfully ugly K9370 airframe that flew with the Fairey Monarch though.
 
True - the rate of progress in the second half of the 1930s was phenomenal. Which makes the continued success of the Spitfire (and to a lesser degree the Bf 109) all the way through WW2 all the more remarkable.
 
Tony Williams said:
Yes, but that is relatively inefficient compared with concentrating the cannon in the nose (it also adds weight out on the wings - roll rate....). There were also problems with fine-tuning all Hispano wing installations, even the big Blackburn Firebrand, because it was intended for a much more rigid mounting.

Wing guns may have had their issues but they pale into nothingness compared to every multi engine propeller plane with engines on the wings that tried to dogfight with a single engine fighter. Even the hotrods like the DH Hornet and Grumman Tigercat were angles fighters taking advantage of high climb rate to stay clear of the curves fighters.

Tony Williams said:
The problem with long shafts taking lots of power is that they have to be very rigid, which among other things means they have to be firmly supported by bearings, and the supporting structure for the bearings has to be very rigid, which adds weight. You're also adding weight with the gearbox (which also has to be rigidly mounted). So there is a weight penalty with a layout like this. Also, while the layout should provide a fast roll rate, I suspect the distribution of weight along much of the length of the plane would make elevator response rather slow.

The drawing as provided was a simple configuration exploration. No attempt to provide for a detailed solution beyond general issues with tandem engines in the fuselage. Interestingly as I posted it the bell struck that it was similar to a WWII Fairey naval proposal. Which after a quick look up in Tony Buttler’s BSP 4 confirmed the configuration from the Fairey ‘Super’ Spearfish and more suitable to this discussion the Fairey Strike Fighter “Project A”.

http://www.secretprojects.co.uk/forum/index.php/topic,10335.msg97102.html#msg97102

These aircraft had two tandem Merlin engines powering a counter rotating propeller in the nose. But they avoided the issue of long drive extension shafts by a very smart engineering configuration. The forward engine was mounted low with the propeller gear box mounted on its drive output. The rear engine was mounted high and immediately to the rear of the forward engine. A drive extension shaft went forward from its output along the top of the forward engine to the gearbox. Like the later Fairey Gannet the counter rotating prop was a simple affair with each engine powering its own propeller and no cross over. The forward engine powered the aft propeller and vice versa. Not only was this a very space efficient configuration with all the advantages of multi-engine through a single propeller (no single engine asymmetrical flight and very low frontal area for drag) it also avoided the complexities of other multi engine in fuselage arrangements like heat build-up from side by side engines and long extension shafts. It also provided a convenient pocket of space above the forward engine and before the aft engine for a pilot’s cockpit with excellent forward vision.

Such a configuration designed in 1938-40 would provide a fighter with about 25% more frontal area than a Spitfire but twice the engine power and about the same weight (if a single seater) as the Typhoon with 50% more engine power. With of course twin engine reliability and no prop torque/helical propwash problems. It would also be able to roll unlike any other twin engine aircraft and have the weight margins to carry a navigator and high fuel fraction for long range interdiction operations if the user was so inclined. 40’ long and with a span of under 50’ it would also be smaller than any other twin engine combat aircraft and not much bigger than single engine fighters (about 20-25% bigger). It would obviously cost more thanks to having two engines but you could do a lot more with it further from home and not have to run from the enemy’s fighters.
 
Well, all fighter pilots need to know the strengths and weaknesses of their planes by comparison with the enemy's, and to do their best to play to their strengths. Given the power to weight ratio of my MP proposal, it could be expected to have a high rate of climb as well as high speed relative to contemporary single-engined fighters. So, as Allied pilots found, first when dealing with Italian planes and next with Japanese ones, you don't dogfight with a more manoeuvrable enemy. Having more performance does at least give you the initiative in deciding when and how to attack.

One issue with any contraprop proposal is the potential reduction in performance due to the aft propeller being in the very disturbed propwash of the front one. I don't know what the percentage effect on thrust is, but I think it's significant. As far as I can recall, some of the later Spitfires were the only RAF fighters to use contraprops, and that was presumably because the short undercarriage limited the propeller diameter, so it was the only way to soak up their extra power.
 
Tony Williams said:
Well, all fighter pilots need to know the strengths and weaknesses of their planes by comparison with the enemy's, and to do their best to play to their strengths. Given the power to weight ratio of my MP proposal, it could be expected to have a high rate of climb as well as high speed relative to contemporary single-engined fighters. So, as Allied pilots found, first when dealing with Italian planes and next with Japanese ones, you don't dogfight with a more manoeuvrable enemy. Having more performance does at least give you the initiative in deciding when and how to attack.

It still doesn’t work well for you if you’re an angles fighter up against a curves fighter and you can’t roll. Roll rate or more accurately time-to-bank and capture x degrees is the most important measure of a fighter’s agility. Because this is what you use to change your vector and respond to changes ie jinking. Planes like the Spitfire and Zero could out turn a Mustang and Hellcat but the later two could roll quickly to get away and then climb/dive away to control the engagement. If you are struggling to roll in your multi engine then you are going to get zapped before you can apply your high power to weight ratio.

Tony Williams said:
One issue with any contraprop proposal is the potential reduction in performance due to the aft propeller being in the very disturbed propwash of the front one. I don't know what the percentage effect on thrust is, but I think it's significant. As far as I can recall, some of the later Spitfires were the only RAF fighters to use contraprops, and that was presumably because the short undercarriage limited the propeller diameter, so it was the only way to soak up their extra power.

It depends on the actual design. Some counter rotating propellers are more efficient some are not.
 
Tony Williams said:
Kadija_Man said:
How would you know if a design had "limited development potential" until it had been built and tested?

You can get a good idea from looking at the aerodynamics and structural design. The Battle seems to have been a rather old-fashioned design, not built for very high speeds.

I would suggest it was an adequate design, considering when it was designed. Indeed, it was quite advanced and when one thinks about the time frame that you're considering it was one of _the_ advanced aircraft of the day. The Falcon would, I dare suggest, have met your requirements and had the advantage it was based on a proven design and would utilise many of the same components and jigs, so its manufacture would have been eased.

The problem with increasing the winspan of any aircraft without compensating by increasing the length to match invariable removes the harmony of the controls. The Bf109 was a handful by the F model and only got increasingly worse after that. I wonder what your proposal would have done to handling? One of its big benefits though would have been to remove those horrible underwing gondolas for the 20mm cannon and moved the weight inwards, perhaps improving roll rate.

Well, I think that the control harmony was pretty well shot by all the weight increases anyway. By all accounts the later 109s were pigs to fly. Adding more wing area should have helped.

Depends upon whom you read. Green makes that claim but several German pilots who flew the late model 109s appear to know otherwise. Narawa (?sp) who interviewed them records that they preferred the 190 for low altitude work but the 109 for high altitude combats. I suspect it had, had it's day by about 1944 and was obsolescent but not quite quite obsolete
 
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