Rikugun Ki-93-Ia - Flying Anti-Tank Gun

[Would you like to see this in-game?]
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Lets clear one thing first: The 57mm cannon mounted on this plane is not the Ho-401 from Ki-102b like some older Western sources incorrectly claim, but a high velocity Ho-402.

ki93-2

Introduction:

It is said the plane was build for the gun or the gun for the plane. Indeed they were build together. It was a combination of that gun, heavy protection and powerful engines, though it was heavy and draggy. In game it would most likely provide a long needed CAS capability for ground realistic battle mode for Japan. For now there isn’t anything very effective for this role in Japanese aircraft tree. You will either have too few bombs or fly very slow, which makes you an easy target. Likely it could also work as bomber iterceptor as well.

For now I haven’t found a lot about the plane’s history, but strangely enough there is a lot of accurate data about it, despite being a prototype aircraft and several good photos as well. Initially the plane was planned to use 2x Ha-211 (Ha-43) 2200hp engines, but this was switched to 2x Ha-214 (Ha-42) 2400hp engines. Both engine types were build by Mitsubishi. In 1945 the first prototype flew once. Unfortunately was damaged in a landing accident and repairs took some time. Before the test flights could continue, it was destroyed in a bombing raid. Some documents mention Ki-93-Ib with an automatic 75mm cannon, but for now there doesn’t seem to be sufficient material about it, so this suggestion only concerns Ki-93-Ia.

How would it perform in game?

The closest comparison is no doubt the American XA-38 Grizzly and with a fair guess Ki-93 would end up on a similar battle rating, though precise battle performance is difficult to predict. Similarly XA-38 had two powerful engines, a large cannon and strong protection. Ki-93 appears to have lower weight with higher engine power, which suggest a better flight performance.

General characteristics

Length: 14.215 m
Wingspan: 18.98 m
Height: 4.84 m
Wing area: 54.75 m²
Empty weight: 7508 kg
Normal load: 10 525 kg
Fuel capacity: 2x 1100 litre fuselage tanks, 200 litre water methanol
Propellers: 6-bladed VDM, 3.80 m (12 ft 6 in) diameter
Powerplant: 2x Mitsubishi Ha-214Fu (Ha-42-31)
Supercharger: 2-stage Vulkan fluid coupling type

  • 2400 hp at 2600 rpm +500 mmHg take-off
  • 2000 hp at 2500 rpm +300 mmHg at sea level
  • 2130 hp at 2500 rpm +300 mmHg at 1600 m
  • 1750 hp at 2500 rpm +300 mmHg at 8300 m

Performance

Maximum speed: 624 km/h (388 mph, 337 kn) at 8300 m (27230 ft)
Cruise speed: 350 km/h (217 mph, 189 kn) at 4000m (13123 ft)
Never exceed speed: ?
Range: 2000 km normal, 3000 km max
Service ceiling: 11 200 m
Time to altitude: 3000 m in 4 minutes 18 seconds
Time to altitude: 6000 m in 9 minutes 3 seconds
Wing loading: 192.24 kg/m²
Power to weight ratio: 0,456 hp/kg

Armament:

1x 57mm Ho-402 - 20rpg
2x 20mm Ho-5 - 600rpg (300rpg in some sources)
1x 12.7mm Ho-103 - 400rpg - in flexible rear mount
2x250kg bombs

The two forward firing 20mm Ho-5 cannons should be fairly good against light ground targets and aircraft which end up in front of it. Ki-93’s biggest issue would certainly be the lacking defensive armament of only a single 12.7mm Ho-103, if it doesn’t have the sufficient flight performance to compete with it’s enemies. At least against quick strafes and light ground fire it is well protected: Even the self-sealing fuel tanks have some armor behind them and they come with CO₂ fire-extinguishers. A water-methanol tank was placed behind those fuselage fueltanks as it is not flammable. For now I am uncertain if the engines had fire-extinguishers as well, but they had some armor. Likely this was for the oil cooling system.

How about the main cannon?

The 57mm Ho-402 cannon was only planned to be used in this aircraft. From what I’ve been able to dig up, it was related to the experimental 57mm Type 1 AT-cannon, which was at one point planned for the Type 4 Chi-To medium tank. In initial plans the magazine was for 30 rounds, but later lowered to 20 and it had fire rate of 80 rounds per minute. The 2.7kg APHE rounds had muzzle velocity of 700m/s, which provides an armor penetration performance almost identical to the Swedish 57mm Akan m/47 mounted in T18B (57).

Sources

Spoiler

『日本陸軍機の計画物語 1980』安藤 成雄 Atsuo Ando

Japanese Heavy Fighters 1937-1945, Dariusz Paduch, 2022

X-Planes of the Imperial Japanese Navy & Army, Nohara, 2000

Japanese Secret Projects: Experimental aircraft of the IJA and IJN 1939-1945, Edwin M. Dyer, 2009

About Ha-214 engine only:

Test engines, specifications and performance. Report No. 16i(7)
国立国会図書館デジタルコレクション

The History of Mitsubishi Aero-Engines 1915-1945, Matsuoka Hisamitsu & Nakanishi Masayoshi

Japanese Aero-Engines 1910-1945, Mike Goodwin & Peter Starkings, 2017

About the Ho-402 cannon only:

Ordnance Technical Intelligence Report Number 19, Ordnance Department, 13.3.1946

雑誌 航空ファン 1997 2 No.92 イラストレイテッド 日本陸軍機 Number Catalog, Bunrindo Co.,Ltd, ?.2.1997

Autocannon, Anthony G. Williams, 17.2.2023

Thanks to Laurelix and Lineins for the data they gathered about Ki-93 for the suggestion on the old forums.
Rikugun Ki-93 - Passed for Consideration - War Thunder - Official Forum

13 Likes

Me want

+1 unique and cool

Reminds me a bit of the T18B (57). I love it! +1

+1

a massive +1 from me

Japan really needs more Attack Aircraft that could fill that role perfectly most likely high Tier III or low Tier IV

Looks nice +1

+1 as TT vehicle

Yes yes yes +1

I’d really want to see this as a TT vehicle for Japan, or at the least as a premium that isn’t event-locked. Japan has very few good TT options, and with them not fixing the Ki-102 anytime soon, this is a must-need.

Also, I’d prefer to see the plane get its on paper engine power of 2300. WT is more about on-paper capabilities anyway

I added some more characteristics and performance data, most importantly the engine power data. It is combination from a report given by Mitsubishi engineers to American intelligence in late 1945 and Mitsubishi engine book. The two give very similar data, but the numbers in the latter appear slightly more precise.

1 Like