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Author Topic: Tachikawa Ki-72...an improved Ki-36?  (Read 8425 times)

Offline cluttonfred

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Tachikawa Ki-72...an improved Ki-36?
« on: April 10, 2009, 12:01:40 pm »
I have a weakness for close support aircraft intended to operate close to the front lines in support of ground troops...the infantryman's friend.  One of the prettiest was the Tachikawa Ki-36 (Allied code name IDA).



Rene Francillon writes in his great JAPANESE AIRCRAFT OF THE PACIFIC WAR:

Quote
An advanced version of the Ki-36 featuring a retractable undercarriage and powered by a 600 hp Hitachi Ha-38 nine-cylinder radial driving a three-blade propeller was designed by Tachikawa under the Ki-72 designation but was not built.

Anybody have any more info, specs or drawings for the Ki-72?
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Offline cluttonfred

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Re: Tachikawa Ki-72...an improved Ki-36?
« Reply #1 on: April 11, 2009, 04:14:19 pm »
Also, on a related note, does anyone have any info or images for the Mitsubishi Ki-35, the plane that the Ki-36 beat to win a production order?
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Offline Apophenia

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Re: Tachikawa Ki-72...an improved Ki-36?
« Reply #2 on: April 12, 2009, 05:19:42 pm »
Sorry, no real details on the Ki-72.

The US War Department's Military Intelligence Service thought that the Ki-72 had replaced Ki.36 production in 1943 (perhaps confusing the Ki-55 with the Ki-72). From "The United States Strategic Bombing Survey", February 1947.

"Until mid-1942 MIS correctly estimated Ida production. Thereafter, until September 1943, Tachikawa produced an average of 25 more of this type each quarter than MIS estimated. After the third quarter of 1943 MIS judged that Ida was replaced at Tachikawa by Ki-72, a plane which was never produced by the company."

The attached image is pure speculation. (A Nakajima-style retractable undercarriage makes sense and the Japanese had the opportunity to examine captured remains of A-27s, Wirraways, etc.)

Offline cluttonfred

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Re: Tachikawa Ki-72...an improved Ki-36?
« Reply #3 on: April 12, 2009, 05:59:36 pm »
Thanks for the info, Apophenia, and the neat artist's impression of what the Ki-72 might have looked like.  The single forward-firing 7.7 mm MG was offset to starboard in the Ki-36, IIRC, which would be about my only suggestion for your sketch.  If the Ki-72 had been produced and followed the example of other IJA aircraft of the period, the forward-firing gun might well have been upgraded to a 12.7 mm Ho-103.  I don't think there is any reason to think that the A-27 or Wirraway would have influenced the design, however, as neither of them was especially successful and the Japanese had plenty of fine domestic examples to follow.  I am still hoping someone may have more on the Ki-72 or Ki-35.

Edit--One other thought:  A rearward-folding landing gear (like the Hellcat or P-40) might have helped balance the presumably higher weight of the new engine and prop with gear up, and the slight forward shift in CG in the landing configuration is not a bad thing in terms of handling at low speeds.  I do agree that the Nakajima type would have been more likely since it was in wider use.  As in your sketch, it certainly seems conceivable to change just the firewall forward installation and wing center section and gear and leaving the rest strengthened if need be but otherwise unchanged.
« Last Edit: April 13, 2009, 07:21:09 am by Mole »
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Offline cluttonfred

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Re: Tachikawa Ki-72...an improved Ki-36?
« Reply #4 on: April 13, 2009, 07:49:07 am »
Here's a nice WWII-vintage clip on YouTube of the Ki-55 advanced trainer variant of the Ki-36 mostly in flight.  Like I said, it sure was a pretty plane.  I think I've managed to embed the video, here you go:



Updated video link as the previous one was no longer available.
« Last Edit: March 02, 2012, 12:05:43 am by Mole »
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Offline lark

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Re: Tachikawa Ki-72...an improved Ki-36?
« Reply #5 on: April 14, 2009, 10:09:32 am »
Since there were large windows for the observer
in the underside of the KI-36, at the wing/fuselage crossing, it would not be so easy
to find room for an inward retracting u.c. in a development version...

Offline Hikoki1946

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Re: Tachikawa Ki-72...an improved Ki-36?
« Reply #6 on: April 14, 2009, 12:21:08 pm »
Only problem was the Japanese had little experience with such landing gear. Case in point is the Ki-87. So problematic was the landing gear that the test pilot of the Ki-87 was forbidden to raise them lest they fail.

Edit--One other thought:  A rearward-folding landing gear (like the Hellcat or P-40) might have helped balance the presumably higher weight of the new engine and prop with gear up, and the slight forward shift in CG in the landing configuration is not a bad thing in terms of handling at low speeds.

Offline cluttonfred

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Re: Tachikawa Ki-72...an improved Ki-36?
« Reply #7 on: April 14, 2009, 12:29:11 pm »
OK, now I'm really intrigued.  I can't find a three-view that shows the bottom of the aircraft (as sometimes is shown in split left right view) but presumably the observer can't see through the pilot's rear end and feet so there would be no reason to put the observer's window in the belly so far forward that it would be in the way of Nakajima-style retractable gear.  I am still hoping someone can find some trace of the Ki-72 design....
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Offline Apophenia

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Re: Tachikawa Ki-72...an improved Ki-36?
« Reply #8 on: April 14, 2009, 05:57:30 pm »
I don't think there is any reason to think that the A-27 or Wirraway would have influenced the design, however, as neither of them was especially successful and the Japanese had plenty of fine domestic examples to follow.

I mentioned the A-27 and Wirraway mostly because the Ki-36 centre section is more Harvard-like than Nakajima (and, of course, the K10W1 Oak had a fixed gear). Lark has identified the real flaw with my speculative view.

Rating success is usually idiosyncratic. Personally, I'd say the Wirraway was more successful (in both intended and unanticipated roles) than the Ki-36.

Offline cluttonfred

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Re: Tachikawa Ki-72...an improved Ki-36?
« Reply #9 on: April 15, 2009, 01:24:47 am »
I would say that the Ki-36 was quite successful in its designed role of light tactical reconnaissance and ground attack--it was effective and well-like by crews in the early stages of the war in China and remained a useful tool in secondary theaters free from the danger of enemy fighters.  The problem was more that the category of light tactical aircraft was unsuccessful.  Off the top of my head I can't think of any WWII aircraft of under 500 hp that was still successful in an armed combat role by the time the U.S. entered the war.  An exception in the very specialized niche of naval spotter and ASW aircraft might be the Vought Kingfisher.
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Offline cluttonfred

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Re: Tachikawa Ki-72...an improved Ki-36?
« Reply #10 on: March 02, 2012, 12:08:33 am »
I am still looking for original drawings of the upgraded Ki-36, the Ki-72, or any information at all on the Ki-36's failed competitor, the Mitsubishi Ki-35.

Cheers,

Matthew
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Offline blackkite

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Re: Tachikawa Ki-72...an improved Ki-36?
« Reply #11 on: March 02, 2012, 12:45:56 am »
Hi! Your requests are very very hard. I can't find any drawings of Ki-35 and Ki-72. :( 
Ki-35 : Basic design was finished, but the IJA did not order Mitsubishi to fabricate prototype model.
Ki-72 : The Project was terminated by the IJA before Tachikawa received the order to develop.
« Last Edit: March 02, 2012, 01:21:54 am by blackkite »


Offline Alcides

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Re: Tachikawa Ki-72...an improved Ki-36?
« Reply #13 on: March 02, 2012, 02:19:32 am »
I don't remember if it has some information about the prototypes, but a very good source of information in the Ida is:

EAGLE EYE SERIES, No. 1
Mitsubishi Ki-51 "Sonia" / Tachikawa Ki-36 "Ida"

http://www.arawasi.jp/salebook.hp/aramag/eye1.html

Excellent with a lots a pictures, profiles and details.

Regards
Alcides

Offline cluttonfred

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Re: Tachikawa Ki-72...an improved Ki-36?
« Reply #14 on: March 02, 2012, 07:01:04 am »
Thanks for the images, Blackkite, many of which are new to me.  They just confirm my belief that the Ki-36/55 were some of the prettiest planes of the war, certainly the Ki-55 has to be in the running for most gorgeous advanced trainer of its day.

Thanks for that suggestion Alcides, I'll be ordering both EAGLE EYE SERIES NO. 1 and THE EAGLES OF MANCHUKUO, 1932-1945.  Not cheap, but considering how much I've read and reread Rene Francillon's JAPANESE AIRCRAFT OF THE PACIFIC WAR, money well spent.

I'll let everyone know if there is anything about the Ki-35 or Ki-72 in either volume.

Cheers,

Matthew
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Matthew Long, Editor
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