Japanese jet or rocket Interceptor "Suzuka-24"

snark

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While cleaning out my deceased Mother-in-law's desk, I found the following (original copy):

Newark Evening News April 14, 1945

Jap’s Jet Plane Like Ball of Fire
GUAM (U.P.) Sgt. Aril Sumwall, Sidney, Mont., reported he saw a jet-propelled Jap fighter over Tokyo in today’s early-morning B-29 raid.
“It looked like a ball of fire or a Roman candle shooting horizontally,” Sumwall said. “It was travelling at high speed and made a run toward our plane. When another Super Fort fired on it, it broke in two parts, both of which crashed in flames.”

I assume this was the last gasp of a mortally-wounded and burning regular air-defense fighter, but...?

Harry
 

Graham1973

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snark said:
I assume this was the last gasp of a mortally-wounded and burning regular air-defense fighter, but...?

That's the most likely explanation, Ohka's were intended to be air-launched anti-ship weapons, but as you said speculation can be interesting.

This copy of a contemporary report from the US gives the basics of how they were used.

 

snark

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Thanks a lot.

I'm sure that Sgt Sumwall would have been impressed by something like your photo #2 headed toward his bomber. I suppose that, in those times and seen from directly ahead, those flames might seem like a rumored new form of propulsion...

Regards, Harry
 

snark

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Hi Thanks for the Me163 testing film.

The first thing I thought of while reading Sgt Sumwall's account was the Mitsubishi J8M development of the Me163, but that aircraft didn't fly until July 7. The Ohka possibility was an afterthought.

I think that, thanks to Orionblamblam [post mysteriously deleted], we have figured it out.

Harry
 

marauder2048

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Orionblamblam said:
snark said:
those flames might seem like a rumored new form of propulsion...

Especially since all most people had seen of rocket propelled aircraft at that point was Flash Gordon, they would have likely assumed that actual rocket planes would have Big Ass Flames coming out the tail. Reality is often somewhat underwhelming compared to assumptions. Insert Political Observation HERE.

I may be misremembering my history but didn't gunnery crews practice against training rockets?
 

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Funny this gets posted right now. I just wrapped B-29 COMBAT MISSIONS, coauthored by the late Steve Pace. In one of the book's many recollections from Superfortress crewmembers, there's mention made of this.
 

snark

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Just FYI, my mother-in-law had saved that particular issue because the main headline was about Pres. Roosevelt's body lying in state. The article discussed here was a tiny item at the bottom of page one and caught my eye. I can probably post a photocopy for your files if you'd like. Harry
 

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Ladies and Gentlemen, I think we may have a winner; the Suzuka-24 (provisional U.S. intelligence designation), though there is a slight mismatch in the known combat history.

Grey Havoc said:
http://sensha-manual.blogspot.ie/2017/10/ohka-based-interceptor-fighter.html

Combat History

The Suzuka-24 saw only two accounts of combat. Both were separate engagements on B-29 formations on April 3rd, 1945. The bomber crew report the Suzuka-24 being a "ball of fire" in accordance to the rocket's discharge. The report lists the rocket lasting for 6 to 8 minutes, where the rocket finally died and the aircraft broke off from the B-29 formation. The crew report matched the fuel time the Suzuka-24 could sustain, 7 minutes. To reach the formation, the Suzuka-24 was given an assisted-rocket on the underside of the central fuselage.

They note the rockets flickering on and off while chasing the bombers. Due to the KR-10's being new and flawed, performance reflected operational use. The Suzuka-24 struggled to get even with the B-29 bombers during its engagement. Overpassing and following behind due to the flickers. The KR-10 by April 3rd were highly experimental. Even when mounted on the J8M prototype months later, the KR-10's operated poorly and even resulted in exploding due to the rocket mixtures.
 

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Could this be another unclassified interceptor, it would seem so.At the end of the war in 1945, most of the vehicles were kept at Suzuka, Yokosuka and Kanoya airfields. American intelligence discovered a model at Suzuka and labeled the aircraft as the Suzuka-24 because the official designation was not known. Four more models of the Suzuka-24 were discovered at Kanoya airfield. At Yokosuka, another model was found along with a pilot belonging to the airfield captured. The pilot listed details of the aircraft, its designated use being bomber intercepting, and measurements of the aircraft. Suzuka-24 is a rocket-based interceptor to counter Allied bombing formations at the end of the war not for kamikaze use like the Okha, but rather to take off and make a strafing run.This new design removed the use of a warhead as its purpose was to intercept the B-29s, the weight of a warhead was considered impractical and dangerous for the design. Instead, a fuel tank and two 20mm cannons were placed in the nose which is why there is no room in the nose to fit any size warhead. With a length of only 6 meters, the 20 mm guns take up a considerable amount of space to properly fit weapon and ammunition belts. The aircraft's design was significantly modified to accommodate its new use. A modified tail design, now introducing a general vertical and horizontal rudder and elevator, allowing for better control of the aircraft in flight. At the same time, a longer wingspan, 0.5 meters longer on each side of the aircraft and a thicker support to allow for easier handling in flight.
The Suzuka-24 saw only two accounts of combat. Both were separate engagements on B-29 formations on April 3rd, 1945. The bomber crew reports the Suzuka-24 being a "ball of fire" in accordance to the rocket's discharge. The report lists the rocket lasting for 6 to 8 minutes, where the rocket finally died and the aircraft broke off from the B-29 formation. The crew report matched the fuel time the Suzuka-24 could sustain, 7 minutes. To reach the formation, the Suzuka-24 was given an assisted-rocket on the underside of the central fuselage.
They note the rockets flickering on and off while chasing the bombers. Due to the KR-10's being new and flawed, performance reflected operational use. The Suzuka-24 struggled to get even with the B-29 bombers during its engagement. Overpassing and following behind due to the flickers. The KR-10 by April 3rd were highly experimental. Even when mounted on the J8M prototype months later, the KR-10's operated poorly and even resulted in exploding due to the rocket mixtures.

Only a general look of the Suzuka-24's specifications are known.
B-29 report on seeing the Suzuka-24 in action.

General characteristics
Crew: 1
Length: 20 feet aprox. (6.097 meters)
Wingspan: 20 feet aprox. (6.097 meters)
Height: N/A
Powerplant: KR-10 (presumed)

Performance
Maximum speed: N/A
Maximum Glide Speed: 840 kmh (520 mph)
Rate of Climb: 10,000 feet per minute (3,050 meters per minute)
Range: 7 minutes of fuel
Service ceiling: 32,000 feet (9,755 meters)

Armament
Guns: x2 20mm Cannons (60 or 150 shells per gun) (Unknown Ho-5 or Type99)
Bombs: None

After the war, the United States encountered many different aircraft. Multiple variations of the Ohka were made and left over in mixed conditions. Because of this, the Suzuka-24 is confused to be an identical Ohka with a warhead, the Model 43B. The Model 43B was similarly designed to hold two 20mm cannons. However the fuselage was extended to carry both the cannons and warhead with fuel for a Ne20 jet engine. https://detail.chiebukuro.yahoo.co.jp/qa/question_detail/q11184146666 - https://detail.chiebukuro.yahoo.co.jp/qa/question_detail/q11175776396?__ysp=5qGc6Iqx - http://www.chibanippo.co.jp/news/national/151501
 

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Dilandu

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Frankly, I doubt about it being powered by KR-10 engine. Such installation would require a lot of efforts, and basically would require building a completely new plane. Not the variation of Okha.

My personal opinion - assuming, of course, that Suzuka-24 is not a myth - is that it was probably powered by a solid-fuel rockets. Japanese solid-fuel boosters were reasonably good, and installing enough of them would actually allow small, very light interceptor to boost to the B-29 altitude and make a firing pass, then glide toward the airfield. This also correspond with its being a variation of Okha.
 

klem

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Frankly, I doubt about it being powered by KR-10 engine. Such installation would require a lot of efforts, and basically would require building a completely new plane. Not the variation of Okha.

My personal opinion - assuming, of course, that Suzuka-24 is not a myth - is that it was probably powered by a solid-fuel rockets. Japanese solid-fuel boosters were reasonably good, and installing enough of them would actually allow small, very light interceptor to boost to the B-29 altitude and make a firing pass, then glide toward the airfield. This also correspond with its being a variation of Okha.
Thanks , Dilandu I sincerely appreciate.
 

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Does anyone have an actual archival citation for the Suzuka-24 designation? I have the original report and sketch of the "Japanese Suicide Interceptor Bomb" shown in this thread and nowhere in the report is it referred to as "Suzuka-24". The report can be found in the USSBS files at NARA II along with a lot of other material on late-war Japanese aircraft projects. There is no mention of a "Suzuka-24" in the descriptions of various Japanese aircraft inspected after the war. The only reason that the B-29 "Fireball" reports seem to be connected to the Ohka is that someone in USAAF intel filed it in the "Baka" file. There is no evidence it was directly connected to the Ohka program, but it was a convenient place to file the report. I did not find any reference in the USSBS "Baka" file to "Suzuka-24". The first designation used for the Ohka by USAAF intel was "Viper". The name was changed in April 1945 to Baka after the inspection of captured Ohka's on Okinawa. The timeline for the attacks on the B-29s does not fit well with an Ohka-based interceptor, Suzuka-24 or otherwise. Has anyone considered that the attacks on the B-29s might have been an operational test of an I-Go missile? These were available in the time frame, even though I have never seen any reference to an attempted operational launch against B-29s.
 

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This, apparently. Could be from UK archives?

new1.PNG

Its quite possible it never existed.
 
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The Ohka was a bomber, it was designed to go down, not to climb like a fighter. In my opinion it is a fake. Jean Barbaud Art.
 

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Dilandu

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Has anyone considered that the attacks on the B-29s might have been an operational test of an I-Go missile?
Er, but I-Go missile was anti-surface weapon. Maybe you meant Funryu missile? They were surface-to-air missiles, but according to available source, they were only in early testing phase.

img_4_m-jpg.374515
 

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Has anyone considered that the attacks on the B-29s might have been an operational test of an I-Go missile? These were available in the time frame, even though I have never seen any reference to an attempted operational launch against B-29s.
The I-Go missile was for use against ships. It was radio controlled, and the launching plane had to be near enough to see and send signals to it for guidance. There was no report of any kind of "mother ship" in the area, and I don't think an I-Go could be launched from the ground and guided toward a B-29 formation, let alone actually hit one. But I guess stranger things have happened.
 

windswords

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Has anyone considered that the attacks on the B-29s might have been an operational test of an I-Go missile?
Er, but I-Go missile was anti-surface weapon. Maybe you meant Funryu missile? They were surface-to-air missiles, but according to available source, they were only in early testing phase.

img_4_m-jpg.374515
The Funryu 1 was actually an anti-ship missile that was launched from a mother plane like the I-Go's. The follow on Funryu 2 and 4 were air to surface weapons, which is why they were larger since they had to travel all the way from the ground to the target.

I don't think Funryu 4 is the likely culprit here, even though it uses the same engine as the J8M: As Dilandu stated, it was only bench tested, and that testing ended on 16 August 1945.
 

Dilandu

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and I don't think an I-Go could be launched from the ground and guided toward a B-29 formation, let alone actually hit one.
No, it couldn't. It have specific heading control: the gyro always maintained initial heading, and "left" or "right" command detached the gyro from controls while gyro still maintained the initial position - so after command transmission ended, missile returned to original heading. In essense, I-Go did not "turn" as much as it "side-stepped", while continuing to go in the same direction.
 
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Dilandu

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The Funryu 1 was actually an anti-ship missile that was launched from a mother plane like the I-Go's. The follow on Funryu 2 and 4 were air to surface weapons, which is why they were larger since they had to travel all the way from the ground to the target.
Surface-to-air, to be exact)

I don't think Funryu 4 is the likely culprit here, even though it uses the same engine as the J8M: As Dilandu stated, it was only bench tested, and that testing ended on 16 August 1945.
Agreed. And Funryu-2, while commenced some flight testing and at least one guided test flight, was clearly not ready in April, 1945.
 

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There are plenty of those to go around.
 

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Now could an Ohka have some fuel be put it it’s nose in the field to replace the bomb as a one off? You always have tinkerers. No bomb , some ammo up front…a bodge for which there would be no paperwork?
 

iverson

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Now could an Ohka have some fuel be put it it’s nose in the field to replace the bomb as a one off? You always have tinkerers. No bomb , some ammo up front…a bodge for which there would be no paperwork?
I doubt it. I think that the operational missiles were powered by solid-fuel rockets.
 

Dilandu

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Now could an Ohka have some fuel be put it it’s nose in the field to replace the bomb as a one off? You always have tinkerers. No bomb , some ammo up front…a bodge for which there would be no paperwork?
Not the basic one. The basic Ohka was powered by three solid-fuel rockets in her tail; it's pretty much impossible to add fuel to her nose. But it is possible, that additional solid-fuel boosters could be fitted externally (dropping away after burnout):

TAICBaka.jpg


If the warhead is replaced by much lighter autocannons, then the thrust-to-weight ratio basically doubled to circa 0.8. Several additional boosters would be capable of lifting Ohka from the field and pushing it to altitude, from which it could do a glide run.
 

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The MXY7 Ohka Model 11was a small mid-wing monoplane with a fuselage of duralumin and wings and tailfins of wood. It has been designed by a transport pilot of the 405th Kokutai, Mitsuo Ohta, in August 1944. He inspired himself on the radio guided German bombs Hs 293 and Fritz-X that were launched from an aircraft flying almost on the vertical of the target.

The operational procedures established that the Ohka should be launched from between 16 and 37 km of distance to the target and at between 6,000 and 8,200 m of altitude. Following its flying profile, the Mitsubishi G4M2e Model 24J bombers that carried them were usually detected by the radars of the Allies from a distance of 130 km. Once detected, the fighters on CAP missions over the fleet could intercept the Bettys 111 km from the target. The powerful anti-aircraft defence deployed by the Allies warships in 1945 made almost impossible that a conventional bomber could fly with impunity over one of its Task Groups.

Previous to launch, the Betty initiated a shallow dive until reaching the take off speed of between 280 and 325 kph. The Ohka flight began as a shallow, unpowered dive, on a 5º 35’ gliding angle, reaching a cruise speed of between 370 and 450 kph. Some of the machines of the Model 11 last series carried a couple of Toku-Ro.1 Type 1 rockets under the wing roots that generated 300 kg of thrust during 10 seconds with the purpose of increasing its speed and range.

At a distance of between 3,000 and 8,000 m from the target, the pilot pressed the button on the top of the control stick to start the electric ignition of the three Toku-Ro.1 Type 2 rockets at the rear section of the fuselage. Each rocket had a length of 179 cm and a diameter of 25 cm, weighted 115 kg and contained 44 kg of solid fuel capable of generating 600 kg of thrust during 30 seconds. After the ignition, the pilot initiated the final 50º dive on the target reaching a terminal speed of 933 kph.



The Ohka could not be intercepted by the fighters at this stage and its course could only be altered by a direct impact from the heavy AA, due to the inertial momentum of the heavy warhead. Not even the pilot could alter its course as the pressure exercised by the air on the tail surfaces in transonic flight was superior to any muscular work applied to the flight controls.



The warhead had been designed for the destruction of major warships. It had a hardened steel warhead to pierce any armour deck and contained 512 kg of Trinitroanisol explosive. It had a length of 180.6 cm (without the nose priming plug) and a diameter of 60 cm and a weight of 1267 kg, including the three rear bolts. It had a wind air-armed fuse in the nosecone that automatically unblocked itself when the Ohka was released by the launch airplane. There were also four impact fuses at the rear of the warhead, activated by means of a T-handle located to the front right of the cockpit. The pilot carried a parachute for those cases when the bomb fell to the sea before reaching the target. The communication with the launch airplane was made by lights on the instrument panel and a one-way Gosport system of rubber tubing.



Trying to solve some of the operational shortcomings of the Ohka Model 11, the Model 21 was designed as a smaller version that could be carried by the fastest bomber available, the Yokosuka P1Y1 Ginga Model 11. The wingspan was reduced from 5.1 to 4.12 m. due to the smaller space available between the undercarriage legs of the Ginga. The warhead was also reduced to 600 kg. The Model 21 kept the three accelerator rockets of 30 seconds located at the rear section, while the 10 seconds rockets located under the wing roots were replaced by Type 3 rockets of 20 seconds. A one-third reduction in wing area meant that the handling characteristics of the Model 21 were far worse than those of the Model 11 and its range was inferior in spite of using five rockets. In July 1945, during the flight tests of the only prototype built, one of the rockets located under the wings did not ignite and the Ohka went completely out of control. The machine was destroyed and the pilot died.



It was decided to do without the rockets and replace them with the Tsu-11 thermo jet developed by the Kugisho engineers in 1944, based on the Italian technology on the Campini compressor. Originally designed to drive the Yokosuka MXY-9 Shuka, the school version of the rocket interceptor J8M1 Sushui, the Tsu-11 consisted of a conventional reciprocating engine, a single stage compressor wheel and a combustion chamber containing an annular fuel injection system and two igniters plugs that burned the air-fuel mixing creating a thrust of 250 kg.



The reciprocating engine was a 4-cylinder inverted, in line Hitachi Ha 11 Hatsukaze II of 105 hp (Japanese version of the German Hirth HM 504-A2). The Tsu-11 had a length of 220 cm, a diameter of 64 cm and a weight of 200 kg. At full throttle the reciprocating engine reached 3000 rpm and the compressor 9000 rpm. It was flight tested under the bomb bay of a Ginga by the end of 1944.



The version equipped with a Tsu-11 was named Ohka Model 22 and was built in a number of fifty units at the factories of Ichigisho, Aichi Kokuki, Fuji Hikoki, Miguro Hikoki and Murakami Hikoki, although only three of them were actually finished with the Tsu-11 for flying test. To transport the Ohka Model 22, a modified version of the Ginga P1Y3 Model 33 was designed following the model of the Junkers Ju 88 H-1 long range bomber. Its fuselage was enlarged 4 m and its wingspan increased to 22 m.



The operational procedure of the Model 22 established that the Ha 11 should be started by ground crews before take off, using the fuel provided by the Ginga during the flight, until launch. Compared to the system used in the Betty, the Ginga did not have enough room in its bomb-bay for the Ohka pilot to have access to it from the launch airplane. Therefore, he should stay within the Ohka at take off and communicate with the crew in the Ginga using a Gosport system.

Model 22 carried the same warhead of 600 kg than the previous design. A fuel tank of 225 litres was installed between the warhead and the main spar, another of 65 litres between the pilot seat and the engine and a third one of oil, of 10 litres, housed in a dorsal fairing behind the teardrop canopy. The new design had a range of 130 km that allowed the Ginga to reach safety before the fighters arrived. However, its cruise speed was just of 443 kph at full rpm, which made it an easy prey for the Hellcats and Corsairs that surpassed 600 kph. To accelerate during the final plunge, a Toku-Ro.1 Type 3 single rocket with 600 kg of thrust peak during 20 seconds, was suspended under the fuselage, equipped with front and rear cowling to reduce the air drag of the underpowered airplane. The rocket could be detached by a T-handle located on the floor in front of the pilot. Handling at high speed was improved by replacing the control cables from the Model 11 by a system of traction-resistant articulated bars.



To amend the low speed issue of the Model 22, the Tsu-11 was replaced by a Ne-12 B turbojet with a four stage compressor that had been originally developed by Ichigisho to propel the new jet fighter Nakajima J8N1 Kikka. The Ne-12B was a variant of the

Ne-12, a centrifugal turbojet based on the German designs Heinkel-Hirth HeS 8 and HeS 8a , that was lighted up to 350 kg. It had 180 cm of length and a diameter of 74 cm producing 319 kg of thrust at 15,000 rpm.



When the technical information on the more powerful BMW 003 A axial turbojet, with a smaller diameter than the Ne-12 B, was received from Germany by mid July 1944, it was decided to improve its performance. This was actually made by increasing the compressor stages, to reduce the rpm, and adopting a combustion chamber of smaller diameter, similar to the one in the BMW 003A. The new design was named Ne-20, measured 275 cm of length and 62 cm of diameter, weighted 450 kg and produced 475-500 kp of thrust. Its mass production was decided as power plant for the Kikka.



Most of the 40 units of Ne-12 B that have already been built could then be assigned to propel the new series of Ohka designated as Model 33. This model had the same wings and tail surfaces than Model 11, although a little longer fuselage and a warhead of either 800 kg containing 315.2 kg of TNT+PETN or of 900 kg containing 415 kg of RDX explosive. It measured 133 cm of length (without the nose priming plug) and 55 cm. of diameter. The Ohka Model 33 carried one single fuel tank of 250 litres located between the warhead and the main spar. It had a range of 213 km, much wider than the Model 22, and a speed of 643 kph, a little faster than the Hellcat and equivalent to the Corsair speed. The launch airplane should have been the four engine bomber Nakajima G8N1 Renzan that could carry an Ohka suspended under the bomb bay in long range missions or two Ohkas suspended under the wings in medium range missions.

There was a plan to convert part of the production of the Ohka Model 11 to the Model 33 by the end of the war. Considering the limited number of available Ne-12 B engines and Renzan airplanes, the mass production would have not been above thirty units. The Model 33 did not use auxiliary rockets. The possibility of having some of the new Ne-20 turbojet engines by mid 1945, to drive missiles and Tokko airplanes, led the Aichi Kokuki engineers to design the Ohka 43 series. However, the nearly 3 m of length of the engine forced them to adopt a longer fuselage and the lack of the right launch airplanes and the new power of 500 kp available with the Ne-20, advised the creation of an airplane able to take off by itself, fitted with wooden wings and tail planes of a considerable size. The wingspan was widened from 5 to 8.972 m affecting the maximum speed that decreased to values below 600 kph and therefore left it exposed to interception.



The proposal was to build two variants designated Ohka 43-Ko and Ohka 43-Otsu at the Aichi-Gifu and Aichi-Oyaki factories. The first one was a replacement of the Aichi M6A1 Seiran that would be carried and launched from the new Sen Toku submarines of the I-400 series. Its watertight deck hangar had 31 m of length and 3.5 m of diameter and could house either four Ohkas or three Seirans or two Saiuns or four Baikas.

The Ohka, with backward foldable wings, moved over rails along the hangar, fixed to launching cars of 700 kg that could adjust their height and slope to several types of airplanes. With the submarine on the surface, the launch sequence was made with the help of two teams of four and six men respectively and went through a defined procedure. First, manual unblock and opening of the hangar door by means of an hydraulic mechanism; then, connection of the hangar rails with those in the launch ramp using two detachable rails. The Ohka was then pulled over its launch cart up to the start of the ramp (of 24 m of length and 3º 30' of slope) and the whole combination was fixed to the hook of the submarine steam catapult. The hangar door was then closed and secured, the wings unfolded and blocked and starter of the Ne-20 connected to an external wall socket. The Ne-20 was then started and the wall socket disconnected. The pilot gets in the cockpit and tests the telephonic connection with the bridge, the control surfaces, the throttle and the compass. The submarine now sails facing the wind at its maximum speed of 18.7 km and the pilot selects ‘full throttle’ at 11,000 rpm. The crew takes refuge in the conning tower before the catapult is fired, the Ohka takes off and the cart falls to the sea.

In case of individual missions the submarine dives to reach a new launch position. For multiple launches, the well trained crew may launch the four Ohkas in 12-15 minutes. The pilots were equipped with parachutes but did not need radio equipment or oxygen to fulfil their mission. Their assignments might be either to attack the Allies fleets located in Ulithi and Pearl Harbour or vital centres located in the west coast of USA, or to destroy the Gatun and Miraflores floodgates of the Panama Canal, the task for which the Seiran had been designed.



The Ohka 43-Ko carried the same warhead (version of 800 kg) than the Ohka Model 33 but without the nose priming plug. Its fuel tank capacity was of 400 litres and it was located between the warhead and the main spar. The oil tank of 16 litres was between the pilot seat and the turbojet. It could reach targets placed 278 km from the launch point.



The ‘Ko’ version did not use auxiliary dive rockets. It released the folding wingtips by means of electrically activated explosive bolts, during the terminal dive to increase its speed. It was expected that it could surpass the 900 kph when reducing its wingspan to just 2.6 m. At this stage control was obtained by using the tail surfaces that could move in differential mode to act as ailerons. In normal configuration, the Model 43 had 13 sqm of wing surface, 4º 30' of dihedral angle and 2º 30' of tail plane incidence.



The ‘Otsu’ version was designed to take off from a 110 m length straight railway section and hide in the railway tunnels with its wings folded. Developed to avoid the use of conventional aerodromes in a situation of complete aerial superiority of the enemy, it was inspired by the launch procedure of the Messerschmitt P.1079 (July 3, 1942). The idea was to use it in a long range coastal artillery role to counteract the invasion of southern Kyushu, or ‘Olympic Operation’, which was expected to happen on November 1, 1945.



The Model 43-Otsu used a launch cart for take off similar to one used by the naval version but propelled by two Toku-Ro.1 Type 2 rocket engines with 600 kg thrust each and 30 seconds of life and by the power of its own Ne-20 turbojet. At the end of its run the cart was detached and braked by a cable and a counterweight system. At that moment, a third Toku-Ro.1 Type 3 rocket with 600 kg peak thrust and 20 seconds endurance automatically ignited. This was fixed to the fuselage centreline and its nozzle had an 8º 45' slope to make the thrust axis and the gravity centres of the Ohka converge, thus providing maximum lift.

The land version used the same warhead than the naval one but it was armed with two Type 3 machine guns of 13 mm with a rate of fire of 800 rpm located between the warhead and the fuel tank, which capacity had been reduced to 300 lt, and a combat range to 200 km. The guns configuration was inspired by the German air to air rocket bomber Sombold So 344 project and its objective was that the Ohka could break its way towards the Allies Task Forces fighting against the defensive fighters to which it was equal in speed. The ‘Otsu’ kept the mechanism to detach the wingtips of the naval version but was not considered a requirement to equip it with accelerator rockets for the terminal dive. It was expected that it would be able to surpass the 900 kph in a 50º dive with the Ne-20 at full throttle.



All the combat versions of the Ohka were protected from the rear against 12.7 mm ammunition of the Browning M2 machine guns used by the U.S. NAVY interceptors. The pilot seat was armoured and 15 mm steel plates were installed behind his head and shoulders and in the cabin floor under his legs. Frontal armour was considered impossible as the state of technology at the time could not produce armoured glass able to stop the 40 mm projectiles of the naval AA.



Two version of training were built to make the pilots familiar with the Ohka weapons system. The K-1 was an unpowered aircraft with landing skid and warhead replaced by water ballast. It was then succeeded by its refined version K-1-KAI Wakarazuka, derived from the Ohka 43. It was a two seat airplane with double flying controls and one Type 4 Mk I Model 10 rocket for ignition testing. A training rocket catapult with a 100 m long ramp was built in Takeyama, to the west of Yokohama, over a hill of 600 m of altitude located 3,000 m from the airfield where the Ohka gliders should land. Forty five Ohka K-1 and two K-1-KAI were manufactured before Japan surrendered to the Allies.



The Ohka Model 11 that took part in the first combats was overall painted in bright blue. Afterwards a paint scheme was adopted with pale green upper surfaces and pale grey under surfaces. The known units of the Model 22 were overall light grey. The training version units were painted in bright orange at the manufacturing plant, then receiving a dark green coating in the upper surfaces only. In all piloted versions the cockpit interior was factory applied dark green.

Technical Data Model 11 (Model 21) ((Model 22))

Wingspan 5.1 m (4.12 m) ((4.12 m))

Length 6.07 m (5.62m) ((6.88m))

Height 1.16 m (1.16 m) ((1.15 m))

Wing area 6 sqm (4 sqm) ((4 sqm))

Max weight 2140 Kg ((1450 kg))

Max Speed 648 Kph ((443 kph))

Max diving speed 926 kph

Warhead 1267 kg (600 kg) ((600 kg))

Fuel ((290 litres))

Oil ((10 litres))

Range 36 km ((130 km))

Engine 3 rockets (5 rockets) ((one TSu-11))

Launch G4M2e (P1Y1) ((P1Y3))



Technical Data - Model 33 (Model 43A) ((Model 43B))

Wingspan 5m (8.97m) ((8.97m))

Length 7.2 m (8.16 m) ((8.16 m))

Height 1.15 m (1.3) ((1.3))

Wing area 6 sq.m (13 sq.m) ((13 sq.m))

Max weight 2120 kg (2270 kg) ((2260kg))

Max speed 643 kph (596 kph) ((596 kph))

Warhead 900 kg (800 kg) ((790Kg))

Fuel 250 litres (400 litres) ((300 litres))

Oil 10 litres (16 litres) ((16 litres))

Range 213 km (278 km) ((200 km))

Engine one Ne-12B (one Ne-20) ((one Ne-20))

Launch G8N1 (Submarine I-400 Class) ((Railway))
 

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airman

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I suppose that Suzuka24 aircraft was based about something information about Ocka Model43B .
 

blockhaj

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For me the Suzuka 24 makes sense design wise and period wise. If real then it could have been some type of field modification of Ohka bombs as temporary interceptors.
 

foiling

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The MXY7 Ohka Model 11was a small mid-wing monoplane with a fuselage of duralumin and wings and tailfins of wood. It has been designed by a transport pilot of the 405th Kokutai, Mitsuo Ohta, in August 1944. He inspired himself on the radio guided German bombs Hs 293 and Fritz-X that were launched from an aircraft flying almost on the vertical of the target.

The operational procedures established that the Ohka should be launched from between 16 and 37 km of distance to the target and at between 6,000 and 8,200 m of altitude. Following its flying profile, the Mitsubishi G4M2e Model 24J bombers that carried them were usually detected by the radars of the Allies from a distance of 130 km. Once detected, the fighters on CAP missions over the fleet could intercept the Bettys 111 km from the target. The powerful anti-aircraft defence deployed by the Allies warships in 1945 made almost impossible that a conventional bomber could fly with impunity over one of its Task Groups.

Previous to launch, the Betty initiated a shallow dive until reaching the take off speed of between 280 and 325 kph. The Ohka flight began as a shallow, unpowered dive, on a 5º 35’ gliding angle, reaching a cruise speed of between 370 and 450 kph. Some of the machines of the Model 11 last series carried a couple of Toku-Ro.1 Type 1 rockets under the wing roots that generated 300 kg of thrust during 10 seconds with the purpose of increasing its speed and range.

At a distance of between 3,000 and 8,000 m from the target, the pilot pressed the button on the top of the control stick to start the electric ignition of the three Toku-Ro.1 Type 2 rockets at the rear section of the fuselage. Each rocket had a length of 179 cm and a diameter of 25 cm, weighted 115 kg and contained 44 kg of solid fuel capable of generating 600 kg of thrust during 30 seconds. After the ignition, the pilot initiated the final 50º dive on the target reaching a terminal speed of 933 kph.



The Ohka could not be intercepted by the fighters at this stage and its course could only be altered by a direct impact from the heavy AA, due to the inertial momentum of the heavy warhead. Not even the pilot could alter its course as the pressure exercised by the air on the tail surfaces in transonic flight was superior to any muscular work applied to the flight controls.



The warhead had been designed for the destruction of major warships. It had a hardened steel warhead to pierce any armour deck and contained 512 kg of Trinitroanisol explosive. It had a length of 180.6 cm (without the nose priming plug) and a diameter of 60 cm and a weight of 1267 kg, including the three rear bolts. It had a wind air-armed fuse in the nosecone that automatically unblocked itself when the Ohka was released by the launch airplane. There were also four impact fuses at the rear of the warhead, activated by means of a T-handle located to the front right of the cockpit. The pilot carried a parachute for those cases when the bomb fell to the sea before reaching the target. The communication with the launch airplane was made by lights on the instrument panel and a one-way Gosport system of rubber tubing.



Trying to solve some of the operational shortcomings of the Ohka Model 11, the Model 21 was designed as a smaller version that could be carried by the fastest bomber available, the Yokosuka P1Y1 Ginga Model 11. The wingspan was reduced from 5.1 to 4.12 m. due to the smaller space available between the undercarriage legs of the Ginga. The warhead was also reduced to 600 kg. The Model 21 kept the three accelerator rockets of 30 seconds located at the rear section, while the 10 seconds rockets located under the wing roots were replaced by Type 3 rockets of 20 seconds. A one-third reduction in wing area meant that the handling characteristics of the Model 21 were far worse than those of the Model 11 and its range was inferior in spite of using five rockets. In July 1945, during the flight tests of the only prototype built, one of the rockets located under the wings did not ignite and the Ohka went completely out of control. The machine was destroyed and the pilot died.



It was decided to do without the rockets and replace them with the Tsu-11 thermo jet developed by the Kugisho engineers in 1944, based on the Italian technology on the Campini compressor. Originally designed to drive the Yokosuka MXY-9 Shuka, the school version of the rocket interceptor J8M1 Sushui, the Tsu-11 consisted of a conventional reciprocating engine, a single stage compressor wheel and a combustion chamber containing an annular fuel injection system and two igniters plugs that burned the air-fuel mixing creating a thrust of 250 kg.



The reciprocating engine was a 4-cylinder inverted, in line Hitachi Ha 11 Hatsukaze II of 105 hp (Japanese version of the German Hirth HM 504-A2). The Tsu-11 had a length of 220 cm, a diameter of 64 cm and a weight of 200 kg. At full throttle the reciprocating engine reached 3000 rpm and the compressor 9000 rpm. It was flight tested under the bomb bay of a Ginga by the end of 1944.



The version equipped with a Tsu-11 was named Ohka Model 22 and was built in a number of fifty units at the factories of Ichigisho, Aichi Kokuki, Fuji Hikoki, Miguro Hikoki and Murakami Hikoki, although only three of them were actually finished with the Tsu-11 for flying test. To transport the Ohka Model 22, a modified version of the Ginga P1Y3 Model 33 was designed following the model of the Junkers Ju 88 H-1 long range bomber. Its fuselage was enlarged 4 m and its wingspan increased to 22 m.



The operational procedure of the Model 22 established that the Ha 11 should be started by ground crews before take off, using the fuel provided by the Ginga during the flight, until launch. Compared to the system used in the Betty, the Ginga did not have enough room in its bomb-bay for the Ohka pilot to have access to it from the launch airplane. Therefore, he should stay within the Ohka at take off and communicate with the crew in the Ginga using a Gosport system.

Model 22 carried the same warhead of 600 kg than the previous design. A fuel tank of 225 litres was installed between the warhead and the main spar, another of 65 litres between the pilot seat and the engine and a third one of oil, of 10 litres, housed in a dorsal fairing behind the teardrop canopy. The new design had a range of 130 km that allowed the Ginga to reach safety before the fighters arrived. However, its cruise speed was just of 443 kph at full rpm, which made it an easy prey for the Hellcats and Corsairs that surpassed 600 kph. To accelerate during the final plunge, a Toku-Ro.1 Type 3 single rocket with 600 kg of thrust peak during 20 seconds, was suspended under the fuselage, equipped with front and rear cowling to reduce the air drag of the underpowered airplane. The rocket could be detached by a T-handle located on the floor in front of the pilot. Handling at high speed was improved by replacing the control cables from the Model 11 by a system of traction-resistant articulated bars.



To amend the low speed issue of the Model 22, the Tsu-11 was replaced by a Ne-12 B turbojet with a four stage compressor that had been originally developed by Ichigisho to propel the new jet fighter Nakajima J8N1 Kikka. The Ne-12B was a variant of the

Ne-12, a centrifugal turbojet based on the German designs Heinkel-Hirth HeS 8 and HeS 8a , that was lighted up to 350 kg. It had 180 cm of length and a diameter of 74 cm producing 319 kg of thrust at 15,000 rpm.



When the technical information on the more powerful BMW 003 A axial turbojet, with a smaller diameter than the Ne-12 B, was received from Germany by mid July 1944, it was decided to improve its performance. This was actually made by increasing the compressor stages, to reduce the rpm, and adopting a combustion chamber of smaller diameter, similar to the one in the BMW 003A. The new design was named Ne-20, measured 275 cm of length and 62 cm of diameter, weighted 450 kg and produced 475-500 kp of thrust. Its mass production was decided as power plant for the Kikka.



Most of the 40 units of Ne-12 B that have already been built could then be assigned to propel the new series of Ohka designated as Model 33. This model had the same wings and tail surfaces than Model 11, although a little longer fuselage and a warhead of either 800 kg containing 315.2 kg of TNT+PETN or of 900 kg containing 415 kg of RDX explosive. It measured 133 cm of length (without the nose priming plug) and 55 cm. of diameter. The Ohka Model 33 carried one single fuel tank of 250 litres located between the warhead and the main spar. It had a range of 213 km, much wider than the Model 22, and a speed of 643 kph, a little faster than the Hellcat and equivalent to the Corsair speed. The launch airplane should have been the four engine bomber Nakajima G8N1 Renzan that could carry an Ohka suspended under the bomb bay in long range missions or two Ohkas suspended under the wings in medium range missions.

There was a plan to convert part of the production of the Ohka Model 11 to the Model 33 by the end of the war. Considering the limited number of available Ne-12 B engines and Renzan airplanes, the mass production would have not been above thirty units. The Model 33 did not use auxiliary rockets. The possibility of having some of the new Ne-20 turbojet engines by mid 1945, to drive missiles and Tokko airplanes, led the Aichi Kokuki engineers to design the Ohka 43 series. However, the nearly 3 m of length of the engine forced them to adopt a longer fuselage and the lack of the right launch airplanes and the new power of 500 kp available with the Ne-20, advised the creation of an airplane able to take off by itself, fitted with wooden wings and tail planes of a considerable size. The wingspan was widened from 5 to 8.972 m affecting the maximum speed that decreased to values below 600 kph and therefore left it exposed to interception.



The proposal was to build two variants designated Ohka 43-Ko and Ohka 43-Otsu at the Aichi-Gifu and Aichi-Oyaki factories. The first one was a replacement of the Aichi M6A1 Seiran that would be carried and launched from the new Sen Toku submarines of the I-400 series. Its watertight deck hangar had 31 m of length and 3.5 m of diameter and could house either four Ohkas or three Seirans or two Saiuns or four Baikas.

The Ohka, with backward foldable wings, moved over rails along the hangar, fixed to launching cars of 700 kg that could adjust their height and slope to several types of airplanes. With the submarine on the surface, the launch sequence was made with the help of two teams of four and six men respectively and went through a defined procedure. First, manual unblock and opening of the hangar door by means of an hydraulic mechanism; then, connection of the hangar rails with those in the launch ramp using two detachable rails. The Ohka was then pulled over its launch cart up to the start of the ramp (of 24 m of length and 3º 30' of slope) and the whole combination was fixed to the hook of the submarine steam catapult. The hangar door was then closed and secured, the wings unfolded and blocked and starter of the Ne-20 connected to an external wall socket. The Ne-20 was then started and the wall socket disconnected. The pilot gets in the cockpit and tests the telephonic connection with the bridge, the control surfaces, the throttle and the compass. The submarine now sails facing the wind at its maximum speed of 18.7 km and the pilot selects ‘full throttle’ at 11,000 rpm. The crew takes refuge in the conning tower before the catapult is fired, the Ohka takes off and the cart falls to the sea.

In case of individual missions the submarine dives to reach a new launch position. For multiple launches, the well trained crew may launch the four Ohkas in 12-15 minutes. The pilots were equipped with parachutes but did not need radio equipment or oxygen to fulfil their mission. Their assignments might be either to attack the Allies fleets located in Ulithi and Pearl Harbour or vital centres located in the west coast of USA, or to destroy the Gatun and Miraflores floodgates of the Panama Canal, the task for which the Seiran had been designed.



The Ohka 43-Ko carried the same warhead (version of 800 kg) than the Ohka Model 33 but without the nose priming plug. Its fuel tank capacity was of 400 litres and it was located between the warhead and the main spar. The oil tank of 16 litres was between the pilot seat and the turbojet. It could reach targets placed 278 km from the launch point.



The ‘Ko’ version did not use auxiliary dive rockets. It released the folding wingtips by means of electrically activated explosive bolts, during the terminal dive to increase its speed. It was expected that it could surpass the 900 kph when reducing its wingspan to just 2.6 m. At this stage control was obtained by using the tail surfaces that could move in differential mode to act as ailerons. In normal configuration, the Model 43 had 13 sqm of wing surface, 4º 30' of dihedral angle and 2º 30' of tail plane incidence.



The ‘Otsu’ version was designed to take off from a 110 m length straight railway section and hide in the railway tunnels with its wings folded. Developed to avoid the use of conventional aerodromes in a situation of complete aerial superiority of the enemy, it was inspired by the launch procedure of the Messerschmitt P.1079 (July 3, 1942). The idea was to use it in a long range coastal artillery role to counteract the invasion of southern Kyushu, or ‘Olympic Operation’, which was expected to happen on November 1, 1945.



The Model 43-Otsu used a launch cart for take off similar to one used by the naval version but propelled by two Toku-Ro.1 Type 2 rocket engines with 600 kg thrust each and 30 seconds of life and by the power of its own Ne-20 turbojet. At the end of its run the cart was detached and braked by a cable and a counterweight system. At that moment, a third Toku-Ro.1 Type 3 rocket with 600 kg peak thrust and 20 seconds endurance automatically ignited. This was fixed to the fuselage centreline and its nozzle had an 8º 45' slope to make the thrust axis and the gravity centres of the Ohka converge, thus providing maximum lift.

The land version used the same warhead than the naval one but it was armed with two Type 3 machine guns of 13 mm with a rate of fire of 800 rpm located between the warhead and the fuel tank, which capacity had been reduced to 300 lt, and a combat range to 200 km. The guns configuration was inspired by the German air to air rocket bomber Sombold So 344 project and its objective was that the Ohka could break its way towards the Allies Task Forces fighting against the defensive fighters to which it was equal in speed. The ‘Otsu’ kept the mechanism to detach the wingtips of the naval version but was not considered a requirement to equip it with accelerator rockets for the terminal dive. It was expected that it would be able to surpass the 900 kph in a 50º dive with the Ne-20 at full throttle.



All the combat versions of the Ohka were protected from the rear against 12.7 mm ammunition of the Browning M2 machine guns used by the U.S. NAVY interceptors. The pilot seat was armoured and 15 mm steel plates were installed behind his head and shoulders and in the cabin floor under his legs. Frontal armour was considered impossible as the state of technology at the time could not produce armoured glass able to stop the 40 mm projectiles of the naval AA.



Two version of training were built to make the pilots familiar with the Ohka weapons system. The K-1 was an unpowered aircraft with landing skid and warhead replaced by water ballast. It was then succeeded by its refined version K-1-KAI Wakarazuka, derived from the Ohka 43. It was a two seat airplane with double flying controls and one Type 4 Mk I Model 10 rocket for ignition testing. A training rocket catapult with a 100 m long ramp was built in Takeyama, to the west of Yokohama, over a hill of 600 m of altitude located 3,000 m from the airfield where the Ohka gliders should land. Forty five Ohka K-1 and two K-1-KAI were manufactured before Japan surrendered to the Allies.



The Ohka Model 11 that took part in the first combats was overall painted in bright blue. Afterwards a paint scheme was adopted with pale green upper surfaces and pale grey under surfaces. The known units of the Model 22 were overall light grey. The training version units were painted in bright orange at the manufacturing plant, then receiving a dark green coating in the upper surfaces only. In all piloted versions the cockpit interior was factory applied dark green.

Technical Data Model 11 (Model 21) ((Model 22))

Wingspan 5.1 m (4.12 m) ((4.12 m))

Length 6.07 m (5.62m) ((6.88m))

Height 1.16 m (1.16 m) ((1.15 m))

Wing area 6 sqm (4 sqm) ((4 sqm))

Max weight 2140 Kg ((1450 kg))

Max Speed 648 Kph ((443 kph))

Max diving speed 926 kph

Warhead 1267 kg (600 kg) ((600 kg))

Fuel ((290 litres))

Oil ((10 litres))

Range 36 km ((130 km))

Engine 3 rockets (5 rockets) ((one TSu-11))

Launch G4M2e (P1Y1) ((P1Y3))



Technical Data - Model 33 (Model 43A) ((Model 43B))

Wingspan 5m (8.97m) ((8.97m))

Length 7.2 m (8.16 m) ((8.16 m))

Height 1.15 m (1.3) ((1.3))

Wing area 6 sq.m (13 sq.m) ((13 sq.m))

Max weight 2120 kg (2270 kg) ((2260kg))

Max speed 643 kph (596 kph) ((596 kph))

Warhead 900 kg (800 kg) ((790Kg))

Fuel 250 litres (400 litres) ((300 litres))

Oil 10 litres (16 litres) ((16 litres))

Range 213 km (278 km) ((200 km))

Engine one Ne-12B (one Ne-20) ((one Ne-20))

Launch G8N1 (Submarine I-400 Class) ((Railway))
Outstanding drawings.
 

Temistocle

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Theare are some descriptions of Japanese rocket planes encountered during B-29 missions over Japan, for example:

186.jpg
(21st Bomber Command Tactical Mission Report 186, page 33)

183a.jpg
183b.jpg
(21st Bomber Command Tactical Mission Report 183, pages 34-35)

137.jpg
(21st Bomber Command Tactical Mission Report 210 212, page 37)

All these documents (and many others) are available here: Japan Air Raids on Scribd
I am also collecting info form these documents about "ball-of-fires" and ground-to-air rockets, but I still need to find some real description of these "secret weapons"(?) (IJN rockets apart, obviously, they are pretty known and described, for example, in this thread: Japanese-anti-aircraft-rockets-ww2)

EDIT: There are small info (and no pictures) about ground-to-air rockets in the book "Japanese Special Attack Aircraft and Flying bombs" by R. Ishiguro and T. Januszewski:
IJA: Tokkusho Kogata Bakugekki and Sa-Go (page 225, just a paragraph)
IJN: Kokukyoku Shusu-shiki Kayaku (pages 236-238, with hypotetical 3-views drawings).
 
Last edited:

QAZ

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There's a lot of stories from the US side of the war regarding the Ōka being used against B-29s, or nondescript "rocket planes". Both in documented combat reports and from the recollection of crews.

From the records of the Japanese side it's known that there was not an interceptor model of the Ōka actually developed, although it seems like there were preliminary plans at points. There's no known record of the standard Ōka model being used against the B-29 either.
If we consider the possibility anyway, wouldn't it be quite difficult for a laden G4M2 to get to an interception position against the B-29 to launch?

Most or all cases are probably explained by overactive imagination, and/or air-launched rocket bombs, or perhaps even RATO units equipped to piston fighters to aid the interception ability. Similar things were tried. The data the US side used to speculate an Ōka interceptor seems to have been mainly based on unclear information about the Shūsui mixing with the Ōka.

---

But, I don't think it's necessarily out of the question that a rudimentary weapon of sorts could have been attempted and simply forgotten, so I'd like to entertain the possibility. There were a few of this kind of weapon developed in Japan, most can be confidently ruled-out as unready by the end of the war, but a couple have almost no surviving information even in Japanese sources.

In terms of the engine, it would most likely need to be a powder rocket, meaning a very short power-time and needing a mother aircraft to bring it to launch. I'm certain no turbojet could have been used in such a weapon, and would not give a bright 'fire' anyway. The liquid rocket 'KR10'/'Toku-Ro Mk.2' was barely useable at the end of the war, and absolutely prioritized for the 'Shūsui' fighter.
The Army had developed the liquid rocket 'Toku-Ro Mk.1' in later 1944, this is the only alternative that could have a somewhat lengthy time of propulsion, but not long enough to make it an independent vehicle.

A few candidates and those which can be ruled out. Mainly, I am listing these to clear up some confusion:

A type of 'Ōka' with liquid-rocket or turbojet:
Simply put, it's very unlikely that such a development went unrecorded in Japan, and there was not really a suitable power unit at the time. The Ōka had originally been proposed with a liquid rocket engine, but the type that was actually completed would need a significant redesign to store enough fuel for useful interception time.

Funryū
This is a SAM developed by the IJN, there were models with either a powder rocket or liquid-rocket, but it was not ready by the end of the war, and never used in combat.

'Winged Rocket'/Shūsui-type Rocket
An unmanned power-rocket propelled ramming body that was similar in form to the J8M Shūsui, but it was not built by the end of the war.

Special Small Bomber
This was evidently a Navy unmanned missile/flying bomb of sorts with a 530 kg warhead and rocket with about 9 seconds of burn time. It was to be used against bomber formations. There is nothing else known about the machine other than that there was a small and large model. It's not clear if it was manufactured.

Sa-Gō
This was an Army air-to-air unmanned guided missile with a liquid rocket giving propulsion, almost certainly Toku-Ro Mk.1. It was developed in 1944, the first unit was supposed to be completed by Mitsubishi in August (putting it on a similar timeframe to the I-Gō anti-ship guided missile, which was considered practical by the end of the war), but it's unclear what actually resulted.

---

I've seen some interesting things in allied intelligence papers regarding their own curiosity on the phenomena. Apart from the 'Suzuka 24' theory, there was apparently a report captured in the Philippines about a sonic-guided missile with bamboo construction. I'm fairly confident I remember reading about a Ki-67 supposedly being shot down while carrying a "robot bomb" as well.

In the future I'm going to try to compile all the related info on this subject and make a comprehensive writeup.
 

windswords

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Nice writeup QAZ!
This made me wonder; could a model of the Ohka with a warhead replaced by say, 2X20 mm cannons have been launched from the ground by solid rockets? What about a launch ramp or rail with a rocket powered sled for initial acceleration, and then 3 solid fuel rockets, one under each wing and the fuselage that would eject when spent, to gain altitude and then the 3 internal rockets for a short powered flight to close with the bomber formation? Could that work? Even if the fuel ran out, by then there would be enough speed to make a pass at the bomber stream I would think. The wing span would have to be larger, and maybe the tail also to be able to maneuver at the heights of the bombers, but I believe that one of the follow on models (43 perhaps?) called for that.
 

Dilandu

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This made me wonder; could a model of the Ohka with a warhead replaced by say, 2X20 mm cannons have been launched from the ground by solid rockets?
Well, as I mentioned above -

If the warhead is replaced by much lighter autocannons, then the thrust-to-weight ratio basically doubled to circa 0.8. Several additional boosters would be capable of lifting Ohka from the field and pushing it to altitude, from which it could do a glide run.
- it is possible. With additional boosters installed, and heavy warhead replaced by much lighter autocannons, the "Ohka" could actually be rocket-boosted to required altitude (at least in theory).

But interesting moment:

(21st Bomber Command Tactical Mission Report 186, page 33)
It is specifically mentioned, that supposed rocket interceptor was launched from aircraft, like the usual "Ohka". So, it may be an attempt to use the usual "Ohka"'s against B-29 attacks.
 

Dilandu

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I've seen some interesting things in allied intelligence papers regarding their own curiosity on the phenomena. Apart from the 'Suzuka 24' theory, there was apparently a report captured in the Philippines about a sonic-guided missile with bamboo construction. I'm fairly confident I remember reading about a Ki-67 supposedly being shot down while carrying a "robot bomb" as well.
I would be very grateful for any additional data. Early guided weapons is my specific passion)
 

Foo Fighter

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Could the standard warhead be replaced with a 'shrapnel' weapon and detonated in the bomber stream?

Would that have any chance of success?
 

Dilandu

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Could the standard warhead be replaced with a 'shrapnel' weapon and detonated in the bomber stream?
Easily.

Would that have any chance of success?
If you meahs hitting several bombers at once - I doubt that. With very primitive navigation equipment, available on Okha, it would be very hard to correctly estimate distance (and barely trained kamikaze pilot would not have enough experience anyway). One bomber could be downed by close explosion - the main problem, again, would be the interception itself.
 

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