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World War II
Discuss WWII and the era directly before and after the war from 1935-1949.
Hosted by Rowan Baylis
When did Ki-61 1-d (cannon & mgs) enter war?
California, United States
Joined: July 15, 2010
KitMaker: 296 posts
AeroScale: 76 posts
Posted: Wednesday, April 25, 2018 - 11:11 AM UTC
In exile in the Midwest and all of my resource books are on the West Coast. I have the very neat 1/48 Tamiya Ki-61 Hein (Tony) I-d. Can't find info on when this variant entered service. This is the I-d (Tei - Japanese for "D" I believe): it carried two 20mm IJ HO-5 on the fuselage and two 12.7 cal mgs on the wings - the fuselage is also slightly thinner than the earliest versions I believe. There's a time oriented Group Build I'd like to put it in, but if it only showed up in 1945 (the two kit decals markings are 1945 home defense) it won't do.

Help appreciated.

Christchurch, New Zealand
Joined: February 01, 2006
KitMaker: 1,673 posts
AeroScale: 1,517 posts
Posted: Wednesday, April 25, 2018 - 01:17 PM UTC

Hi Eric this is the best timline I could find for Ki-61 it appears that your particular model entered service in january 1944 but was still operational in 1945.


November 1935: Ki 28 work began in anticipation of the 1936 Fighter Competition. With its

Ha-9-II Ko / 800 hp. engine it could reach 301.

1936 Competition: The Ki 28 demonstrated sparkling performance in speed, acceleration

and climb against the Mitsubishi Ki 33 and Nakajima Ki 27. "Although it had a wider turn

radius, the Ki 28's higher speed ensured that the aircraft could travel 360 degrees in the

same lapsed time as the other fighters." The Ki 27 was the most maneuverable of the three.

December 1940: The first of 12 Ki 61 prototypes was completed, S/N 6101.

2nd week of December 1940: 1st flight. Kawasaki Ha-40 (Licensed Daimler Benz DB 601A): 1,150 hp.

18 April 1942: Warrant Officer Ryozaburo Umekawa was relaxing on the ground smoking a cigarette

with Major Yoshitsugu Aramaki at Mito airfield when they were alerted to the Doolittle Raid on

Tokyo. With Binoculars they spotted a medium-size US aircraft flying at about 650 ft. They had

been flying gunnery trials. WO Umekawa attempted to intercept a b-25B heading south at 1000 ft.

with non-explosive ammunition. He managed to make three passes and hit near the wing root of

the bomber, noting oil or fuel streaming back. Lack of fuel forced WO Umekawa to turn back. This

was the 1st combat sortie of the Ki 61.

Note: Fore a more comprehensive report of this interception which included A6M2s and Ki 27s read

Aircraft of the Aces No.114, "Ki-61 and Ki-100 ACES" by Nicholas Millman.

August 1942: Twelve test aircraft had been completed. When test flown against the P-40E, Bf 109E,

Ki.43-II and Ki.44-I, the Ki.61 was deemed to have the best performance overall.

December 1942: The 68th Sentai began transitioning from Nakajima Ki 27s to Kawasaki Ki 61s at

the Akeno Rikugun Koku Gakko ( Army Aviation School ) in Japan. 34 Ki.61s had been produced.

Retractable tail wheel.

Armament: 2 x 12.7 mm. Ho-103 machine cannon in the cowl + 2 x 7.7 mm machine guns, wings.

Note: The Japanese Army designated any automatic weapon above 11 mm. as a machine cannon.

January 1943: Production Ki 61-la/Ko are delivered with.

Engine: Kawasaki Ha-40: 1,175 hp./2,500 rpm./T.O. 1,100 hp./2,400 rpm./13,780 ft. (4,201 m.).

Compression ratio: 6.9:1

Armament: 2 x 7.7 mm. type 89 + 2 x 12.7 mm. Ho-103/200 rpg.

April 1943: 68th and 78th Sentais are equipped with the Ki-61-la.

16 June 1943: Ki-61-la 1st combat. 68th Sentai stationed at Wewak, New Guinea.

18 July 1943: First air to air combat was against P-38Gs.

" The P-38 pilots all like the "Tony". It may have been a bit faster than the current Jap fighters

we were fighting, but we had plenty of speed to spare, and the "Tony" was a lot less maneuverable

than either the Zero-Sen or the "Oscar", so it was an easy victory when encountered. It also

appeared , to our delight, that the pilots who flew them were not of the highest skill."

Five-kill Lightning ace Charles King, 39th FS / 35th FG.

August 1943: 800 20 mm. MG 151 cannon with ammunition had been transshipped from a German

submarine to a Japanese Submarine in the Indian Ocean.

September 1943: Special Kawasaki modification teams were sent overseas bases to modify the wing

armament of a proportion of the operational aircraft. Simultaneously all remaining Ki 61-la/Ko airframes

on the Kagamigahara assembly line were modified to take the German MG 151 20 mm. cannon.

Production of the Ki.61-I Hei (Ki.61-Ic) began.

October 1943: 800 20 mm. MG 151 cannon with ammunition had been transshipped from a German

submarine to a Japanese Submarine in the Indian Ocean.

Mid-December 1943: The 78th Sentai received six Ki.61-I Hei (Ki.61-Ic) fighters with German MG 151

20 mm. cannon in the wings.

December 1943: Eight Ki.61-IIs were completed with a bigger wing.

Engine: Kawasaki Ha-140: 1,500 hp./2,750 rpm./T.O. 1,350 hp./2,650 rpm./2,000 m. 1,250 hp./

2,650 rpm./5,700 m. Compression ratio was 7.2:1.

Wing span remained the same but area increased 10% to 236.8 sq. ft.

Redesigned aft canopy for improved visibility.

Poor engine reliability, very weak crankshaft.

Revised airframe was weak and the wing would crack in flight.

Note: Reverting to the standard wing of the Ki.61-I corrected the cracking problem.

Performance of this Ki.61-II was now 394 mph./6,000 m. and 5,000m could be attained in 6 minutes.

January 1944: Ki 61-l-KAId/Tei production models begin to appear with the same armament as the Ki 61-lb.

The fuselage is extended 7.5 in. longer to 29 ft. 2.75 in. Replacing the 12.7 mm. cowl cannon with

the 20 mm. cannon required 200 mm lengthening of the fuselage.

Autumn 1944: Ki 61-l-KAId/Tei has constant problems with wing armament and is discontinued.

Wing armament is 2 x 30 mm. Ho-105 cannon.

Note: Ki 61 pilots adopted hit-&-run tactics to cope with the F6F Hellcat and were proven relatively effective.

April 1944: Ki 61-ll-KAIa / Ko 1st flight. Eight of the Ki.61-II airframes were flown. The ninth became

the Ki.61-II-Kai Ko.

*Armament: 2 x 12.7mm./200 rpg. + 2 x 20 mm./120 rpg.

*Fuselage was lengthened to 32 ft. 2/3 in.

August 1944: Production of the Ki.61-II-Kai began.

September 1944: Ki 61-ll-KAIa begin to appear operationally. 99 aircraft of this type are produced

in the spring

Date ?: Ki 61-ll-KAIb/Otso with an armament of 4 x 20 mm. cannon. Rudder area was enlarged.

January 1945: Production of the Ki.61-I Tei was terminated with 1,358 of this model being produced.

Note: Many of the Ki.61-I Tei had the wing armament and cockpit armor removed to improve high

altitude performance.

Note: Frequent failures of the main bearings, the superchargers and the oil & coolant systems soon

rendered the Ha-140 an even more notoriously unreliable engine than the Ha-40. When it did

function smoothly, however, it was universally admitted that the Ki 61-ll-KAI was a quite outstanding

fighter capable of holding its own with the best Allied warplanes in its class.

Note: One authoritative source reports that only 99 Ki.61-II Kai were eventually delivered and an

unknown quantity of these had the teardrop canopy.


Air International August 1975 Vol.9 No.2.

P-38 Lightning vs. Ki 61 Tony, New Guinea 1943-44

Aircraft of the Aces 114: Ki-61 and Ki-100 Aces by Nicholas Millma
California, United States
Joined: July 15, 2010
KitMaker: 296 posts
AeroScale: 76 posts
Posted: Thursday, April 26, 2018 - 12:02 AM UTC
Thsnks much: January 44 sounds right. The "relatively effective" remarks concerning any Japanese fighter should emphasize the "relatively." Even the best of the second generation planes were a handful for Japanese industry and in US or UK terms would have been considered unacceptable "hangar queens." And none had the structural strength to dive with any US fighter. (A good P-40 fighter had the edge over the early Tonys any day - that was proven in the Wewak and other NG battles. Kenney just wanted more new planes and 38s were desired because of the range. Hence the Tony alarm.) I read an interview by a Japanese officer in the SSB Survey - Pacific and he claimed the P-51 was the most effective US plane. I bet. There were late Ki-61 units that used "special attack" tactics on B-29s - that says a lot. Japan didn't belong in the war after June of 1944 and their pilots were completely outclassed. War of mass production and some guys had the "right stuff" and made kills potentially any time, but those were the exceptions. Air warfare in the PTO was a mugging by 1944. Dangerous still because everybody's planes had non-combat losses in frightening numbers. Life was cheap.
Quebec, Canada
Joined: April 19, 2008
KitMaker: 591 posts
AeroScale: 503 posts
Posted: Tuesday, May 01, 2018 - 10:23 AM UTC
Kai-1d fuselage was not thinner: The nose(engine) was displaced forward 6" to compensate the increased structural and fuel weight.

The 600 lbs extra weight with no extra power made this new variant almost useless compared to the earlier short nosed variant, so these later "d" long nose versions were mostly used for parts (bad variant choice on Tamiya's part!): I have yet to see a single photo of one 1d flying(!)... Being useless and slower for combat, the long nose were also used a lot for Kamikaze attacks.

Like the earlier 20 mm P-39s being much safer and far superior to the later badly out of balance P-39Q/Ns (the Russians were desperate to reverse engineer this), the earlier Ki-61s were kept flying as long as possible, so you only see the early short nose used operationally later in 1945 Japan against B-29s (Kobayashi etc): The later long nose would have been useless with their extra 600 lbs, and even earlier Ki-61s were near useless with the weight of guns, hence ramming attacks on B-29s... Ki-61 was good in diving and zooming, as well as turning to right. Speed was poor at 595 km/h since many of the others, N1K1, Ki-44 were 650 km/h, and the Ki-84 was 700 km/h. The Ki-100 was the best of them all and could only do 590 km/h(!): Yet it could take on alone against 3 X Ki-84s and defeat them, switch pilots and do it again... Despite the slow speed, the Ki-100 could supposedly take on two P-51s on equal terms... G.