Twin-Boom Superplanes... With A Twist!: Mansyu Ki-98 & Mitsubishi J4M

Hello everyone, how are you doing today? Let's talk a little about radial engines, as the name suggests. Radial motors are circular in shape with arms or spokes extending from a center. Each spoke houses a piston behind that piston is a chamber with a spark plug an intake valve and an exhaust valve a spark plug ignites a fuel mixture in the chamber pushing the piston down as the piston returns, the spent gases they are expelled and more fuel is pumped in and the cycle continues. Each piston is connected to a central hub which is fixed to the crankshaft, these types of engines were incredibly common in the early days of aviation and it's really not difficult to understand why their construction is quite simple as far as engines go, they are Quite durable and can also withstand a decent amount of punishment before failing and generally don't need any type of extensive cooling system attached, although there are certainly liquid-cooled radial engines.

Radials are best known for being simply air cooled, this was achieved by having some type of heat sink. Near the end of the Lightning and the simple act of blowing air over the heatsink in Flight kept it cool. There is no real need for any type of extensive radiator liquid cooling system. Of course, radials aren't exactly perfect and present a clear problem. in resistance because the dies and heatsinks have to be exposed to open air, open airflow automatically means that the aerodynamic rays of the UN are going to create a lot of drag on aircraft that use radials, it's pretty easy to say.

As the nose is usually flat and open, giving the spokes a lot of airflow, this is one of the biggest advantages of liquid-cooled line engines. The nose can be more aerodynamic and closed, so why are we talking about radial engines? In World War II, Japan was quite attached. For them, they didn't really have the manufacturing capabilities or resources to mass produce engines online and generally prefer the reliability that radials offer, plus radials don't need cooling systems and therefore being lighter , they fit perfectly with many of your little ones. lighter fighter designs that in turn gave them fantastic maneuverability.

It's Japan's propensity to use radial engines and the need for radials to have airflow to cool them that I want you to keep in mind when we look at our two subjects today, two almost identical. Late war designs intended to counter Allied attacks on the Japanese homeland. This is the Manu key98 and this is the Mitsubishi j4m. This brings us to the second half of World War II, around 1944, when the war had turned against Japanese and Allied imperial attacks on the continent. Japan was advancing from the Ditt attack in April 1942, which dealt a major psychological blow to the Japanese military, to the slow increase in air raids from early 1944 onwards, to the bombing of Tokyo in March 1945 and the launching of atomic bombs that ended the war As the war progressed, Japan's need for interceptors and high-altitude fighters grew the day one such aircraft that was intended to serve as a high-altitude fighter that would eliminate the bombers attackers was the Manu key98, although the key98 did not actually start out as a fighter, but rather a few years earlier, as a sort of multi-roller SL ground attack fighter, in mid-1942 the Japanese military was looking at potential new designs. , practically anything that served as an improvement on the aircraft already in service, the Manu company, short for Manchurian aircraft.

The manufacturing company created under Japanese government control after the Japanese invasion and takeover of Maneria would largely produce other aircraft under license, but they had some designs of their own and one of which was the Key98. The design of the98 key was unusual. one fitted with a pusher propeller system and a

twin

boom

tail, presumably this was done to help it be a ground attacker as the propeller was not in the front, it would give the pilot a much better view if they were sitting underneath of a bubble style canopy that the pilot would have. at his disposal two 20mm cannons and a 37mm cannon along with presumably underwing points from which to place bombs or rockets, despite being a fairly unusual design, the Japanese military accepted it and Manu began work very slowly into a prototype that was extended to In 1944, although probably due to the increasing prevalence of bombers over Japanese positions and mainland Japan, the more multi-role aspect of the design was ordered to be discarded and the key98 was now to serve exclusively as a high-altitude fighter with its relatively powerful armament, it is safe to assume that it would serve as a bomber.

The destroyer measures 11.4 m long, 11.26 m wide and 4.29 m high. The k98 would be powered by a fairly powerful engine by Japanese standards, the Mitsubishi has 211 or has 43, an 18-cylinder radial. engine with around 2200 horsepower and the K98 is relatively light. All things considered, with an estimated gross weight of just under 10,000 lb, projected performance would be over 450 4 mph at around 30,000 feet. Wind tunnel testing showed the design to be quite promising and in early 1945, work on a prototype would begin in parallel to this design. There was another design that was supposed to serve exactly the same purpose and basically had exactly the same design and also sported a pusher propeller system, a

twin

boom

tail and the same ha 211 engine as the mits.

The iishi j4m, designed in 1944 in response to a call for a new high-power Interceptor, only differed significantly in that the dimensions were slightly larger, measuring 12.98 M long, 12.49 M wide and 3.47 M tall, the j4m ended up weighing about the same, just under. 10,000 lb and was also equipped with two 20mm cannons and a smaller 30mm cannon to complement it, not a 37 mil. Mitsubishi would estimate top speed to be over 470 mph. Now with these two designs there is a fairly clear problem. Remember that The engine used in both was a fairly powerful radial engine and radials usually need air flow to keep them cool.

They could be liquid cooled, but the h211 was not like that, as the engines were located in the body behind the cabin and pretty much covered the issue. Is this exactly how they would cool the engines? Now you may be saying that the solution was clear by looking at the design with these slots in the body that serve as air intakes. Now you are right, but there is something missing with the air slots where they are. if the air passing over the body couldn't travel far enough to them and cool the engine and the designers knew that those slots alone wouldn't give them the airflow they needed, so in key98, at least the proposed solution Actually, it was quite simple.

Not only would the engine drive the propeller rearward, but in front of it, behind those air slots, the engine would drive a fan that would help draw air into those slots. It's kind of like the way your PC cools down and then the air would come back out through the slots in the back now, would this system cause any kind of additional resistance or the kind of resistance that normal radial motors have? To be honest, I'm not sure, and to be fair, I don't think the Japanese military really knew this, as none of these designs would ever fly.

The first project to finish would be the j4m, as another pusher propeller design, the cuu j7w shinden, was believed to be more promising and would fulfill the same role, so work was ordered. Interestingly, although the j4m never made it beyond the initial design stages, it would actually still receive an official designation from the Allied powers. Luke's identifying name After the Allied Forces learned of the project in captured documents or intercepted communications, they believed they would soon see these planes, so they gave him a name and as for the code98, one would last until almost the end of the war .

As Manu was a fairly small entity and would be largely occupied with contracted aircraft, as production of the prototype began in 1945, around August 1945, that prototype had not yet been completed, most of the parts were finished, at minus the important parts of the fuselage wings and tail, but presumably they were not assembled either, they still needed an h 211 engine to put it in and that engine was also in its prototype phase, but before they could assemble it, on August 8, 1945 , 2 days after the first atomic bomb was dropped, but Japan was still in the war, the Soviet Union declared war on Japan knowing they were screwed and with the Soviets making progress in documenting the key98 and ordering the destruction of Japan itself prototype to avoid its capture, which brought an abrupt end to Japan's attempts to manufacture twin-boom pusher propeller aircraft from these several countries that attempted to make these twin-boom pusher propellers with the United States xp54, the Saab 21 from Sweden and S21 from Holland.

Japan was unique in making theirs with an air cooled radial engine, everyone else used liquid cold. probably because the engines were hidden in the body and it doesn't make much sense to use cold air engines this way, but since Japan is basically stuck on using cold air radial engines, they found a way that probably would have worked, but not only their Simple designs were not successful here, nor was the ha 211, which flew only the j7w and a7m before the war ended, and the engine project would end then and there even if Japan had successfully manufactured either of these. double arm aircraft. and they performed as estimated, it still wouldn't have changed things.

I'm very sure Japan would have been able to produce those planes or those engines in a significant capacity. Japan was not just one plane away from changing the course that Japan needed like some. It's some kind of sacred intervention from the Shinto god Fuji, he's the god of wind and he looks a little like Blanca from Street Fighter, and with that we're going to go ahead and wrap it up for today, so thank you all for watching. Remember to like, comment and subscribe, something that is really interesting to me is the accidental convergence of design ideas when countries and companies fall into similar ideas and concepts like the double arm design, it's like the engineering version of the theory of the horseshoe, but anyway I hope you enjoyed the video and I hope you learned something so see you.