Kawasaki Ki-88 fighter project

robunos

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...the Kawasaki Ki-88 was a simpler derivative of the Ki-64, with the nose engine
and the vulnerable surface cooling system removed. It was never built.
Windswords, beat me to it! According to the article I referenced above,

"Also during 1943, the Kawasaki team tendered...
a proposal for a simplified version...in which the forward engine was removed,
and an orthodox cooling system was provided for the centrally mounted engine,
which could be either the Ha-40 (licence-built DB601A), or the more powerful
Ha-140, which was bench running...in 1943.
This alternative to the Ki-64 seems to have been inspired by the lingering doubts
about the ability of the evaporative cooling system to survive battle damage and
some concern about the technical complexity of the tandem engine and propeller
drive system.

...authorised Kawasaki to proceed...on 3 February 1943 under the designation Ki-88...
A mock-up was built...
With the wing and fuselage of the prototype (Ki-88) almost complete...
the Ki-88 was dropped in October 1943."
(my bold)

Hardrada55, the 3-view you've posted is in good agreement with the Ki-88 images
posted in 'Japanese Secret Projects', which I can't post here due to copyright
restrictions, so yes, that is the Ki-88. Do you have a source?

Again from the above article, the production Ki-64, referred to as the Ki-64-KAI,
was to have several improvements over the prototype, the most important of which
was the replacement of the prototype's propeller, (front one variable-pitch, but rear one
fixed-pitch, but see below), with a licence-built German VDM electrically controlled,fully-feathering
constant-speed contraprop, which would allow either engine to be shut down and
re-started in flight. Cruising on one engine only would usefully extend the aircraft's endurance.
Use of the more powerful Ha-140 engine mentioned previously was also foreseen in time.

(In the text, the front propeller is given as the fixed pitch one, whereas the rear propeller is stated
to be of fixed pitch in the key to the cutaway. This may be a mis-understanding, given that the front
propeller was driven by the rear engine, and vice-versa. Putnam's 'Japanese' gives the rear unit as the
fixed pitch one.)


cheers,
Robin.
 

blackkite

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One of the reason why IJA terminated to develop Ki-88 was the low performance of P-39 which shot down easily by Japanese fighter.
 

Apteryx

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There's a Japanese publication about Japanese Imperial Army experimental fighters, FAOW no. 24. It has an article (in Japanese, of course) and 3-view about the Ki-88, which shows mainplanes similar to the Ki-64.
 

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Grey Havoc

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blackkite said:
One of the reason why IJA terminated to develop Ki-88 was the low performance of P-39 which shot down easily by Japanese fighter.
The Imperial Army didn't realise that the P-39's deficient performance at higher altitudes was because it's turbocharger had been deleted in production versions?
 

blackkite

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P-39 was heavy. Wing loading was 57 % larger than Zero. Wing span loading was 60% larger than Zero.
Turning performance and acceleration were not so good.
If she had s turbocharger(also intercooler, piping), her weight became unacceptable. ;D
(Gross weight of P-39 was 3,350kg while Zero type 21 was 2,421kg.)
 

Grey Havoc

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blackkite said:
P-39 was heavy. Wing loading was 57 % larger than Zero. Wing span loading was 60% larger than Zero.
Turning performance and acceleration were not so good.
If she had s turbocharger(also intercooler, piping), her weight became unacceptable. ;D
(Gross weight of P-39 was 3,350kg while Zero type 21 was 2,421kg.)
On the other hand, the Russians had great success with the P-39 at low altitudes, both in ground attack, and against German aircraft. Of course, the Russians mostly used a later variant with a more powerful engine, IIRC, and German fighters were optimised for combat at higher altitudes. The rather lethal T9 cannon that the P-39 was built around may also have been more reliable in colder conditions, such as those prevailing on the Eastern Front, than it was in the South Pacific.

As to the turbocharger/supercharger issue, the benefit from greatly increased performance, especially at above 12,000 ft may have well outweighed the weight penalty of keeping it, not to mention the fact that general work on lighter, more compact superchargers and related developments was ongoing.

Finally, the Zero in particular, and some other Japanese aircraft sacrified things like armor and self-sealing fuel tanks in order to be as lightweight, and therefore as manouverable/long ranged as possible, which worked well, up to a point.
 

Pepe Rezende

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Soviet pilots removed the wing guns, some armor and used the engines above the boost and RPMs limits. An Allison had a 30 hour live with them...

Cheers

Pepe
 

Grey Havoc

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Pepe Rezende said:
Soviet pilots removed the wing guns, some armor and used the engines above the boost and RPMs limits. An Allison had a 30 hour live with them...
I think the armor and gun deletions were field modifications by a few squadrons tasked with intercepting aircraft at higher altitudes.
 

Stargazer2006

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Topic split/merged from two separate ones. Feel free to add to it!
 

Taranov

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Hm... good drawings of Ki-88 published in one of Matsuba Minoru drawings books.
In principal, i can scan it.
 

blackkite

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Hi!

過給器空気取入口 : Super charger air intake
プロペラ延長軸 : Extended propeller shaft
プロペラ減速歯車箱 : Propeller reduction gear box
ラジエーター : Radiator
37mm機関砲 : 37mm cannon
エンジン : Engine

https://en.wikipedia.org/wiki/Kawasaki_Ki-88
 

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hesham

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Thank you my dear Dan,and can we put them together in one piece ?.
 

newsdeskdan

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Not sure about the engine placement and the scale of the pilot in your Ki-88.
Scale pilot?:rolleyes:
I understand that real life people are different sizes so there's no need for your patronising use of the 'rolleyes' emoji. However, I know you also understand that aircraft designers used standard-sized 'models' to depict aircrew. It wasn't a case of some drawings showing little guys and some showing big guys. That would be ridiculous. All the aircrew in design drawings were exactly the same size from one drawing to the next. I have drawings from both Messerschmitt and Heinkel showing the precise dimensions of their standardised aircrew models and depicting them in various poses so that they could be inserted into drawings as required. The Japanese did the same thing.
 

sienar

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Just out of curiosity, what height were the standards for messerschmitt and heinkel?

Here is an example of what was used in the USSR during ww2.
614027
 

newsdeskdan

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Just out of curiosity, what height were the standards for messerschmitt and heinkel?

Here is an example of what was used in the USSR during ww2.
View attachment 614027
I knew you'd ask me that! It might take me a long time to dig them out, since, having got them, I never thought I would actually need them for anything. I'll see if I can locate them.
 

newsdeskdan

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Just out of curiosity, what height were the standards for messerschmitt and heinkel?

Here is an example of what was used in the USSR during ww2.
View attachment 614027
Penzing dimensions.jpg

Well, this isn't exactly what was requested but it's the best I can do at short notice. This was produced by the Heinkel team interned at Penzing shortly after the war when they were having to reproduce their drawings for the Americans and needed to get the dimensions right. NB. The seated height appears to be exactly the same at 900mm but it's hard to tell with the rest owing to the Russian guy's non-fighter pilot posture.
 
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Justo Miranda

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There is no 'standard man'.
As for the well-known anthropologist Dr. T.E. Hertzberg there are men whose weight, stature and sitting height are 'standard'.
But only 7% of population adhere to two of the 'standard' dimensions, a percentage that decrease to 3% when referring to three 'standard' dimensions and under 2% when the considered 'standard' dimensions are four.

I usually work on German designs with a 'standard' stature of 1.717 m but the only statistics I know for the Japanese pilots is of 1.669 m and is dated in 1962.

'Human Dimensions & Interior Space' by Julius Panero and Martin Zelnik. Watson-Guptill, 1979 N.Y.
 

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newsdeskdan

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There is no 'standard man'.
As for the well-known anthropologist Dr. T.E. Hertzberg there are men whose weight, stature and sitting height are 'standard'.
But only 7% of population adhere to two of the 'standard' dimensions, a percentage that decrease to 3% when referring to three 'standard' dimensions and under 2% when the considered 'standard' dimensions are four.

I usually work on German designs with a 'standard' stature of 1.717 m but the only statistics I know for the Japanese pilots is of 1.669 m and is dated in 1962.

'Human Dimensions & Interior Space' by Julius Panero and Martin Zelnik. Watson-Guptill, 1979 N.Y.
I understand that real life people are different sizes. However, I know you also understand that aircraft designers used standard-sized 'models' to depict aircrew. Does that sound familiar?
Returning to the Ki-88, I've figured out what was bugging me about your pilot. Aside from his physical shape being different (I understand that real life people are different sizes etc.), I think it's actually his seating position. He's just a bit too far forward for some reason. I've tried to get the cockpit canopies in the rough comparison below to match up scale-wise so you can see what I mean.

Comparison.jpg
 

newsdeskdan

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You are right, I have moved back the pilot position.
Thanks for helping me to improve the drawing. I must send it to the publishers next month.
It's remarkable how accurate all those old Japanese re-draws actually are. They must have had the originals and basically traced over them.
 

newsdeskdan

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Forgive my ignorance, but can anyone tell me what this bit's for? Is it just the radiator? It doesn't appear to have been stripey originally, then the stripes look to have been added during the first re-draw - perhaps for clarity?

Intake.png
 
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