Japanese Combat Flaps

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jugggo

Airman
57
3
Jul 8, 2009
Various articles or pilots test flight notes state various different aircraft have them like the J2M Ki-44 N1K1 and Ki-43 does anyone know what degree they are deployed and what speeds? References would be awesome if you have them.

Thanks in advance
 
J2M: 50 degree (from J2M2)
Ki-43: 20 degree
Ki-44: 35 degree
N1K1: 30 degree

50 degrees seems a little excessive. The F4U had a 10 degree maneuver flap (combat) the P51D had 8 degrees and 109s had 10 degrees. The combat flap was to help produce a little extra lift at a lower then normal speed to get that advantage in a turn fight. When I was searching the JACAR website I did stumble upon the N1K1 test for air combat flaps and it showed the flap with measurement but I couldn't translate it. The funny thing was it had drawings as the N1K1 as a sea plane.
 
The N1K1 test report showed 10-15% improvements of the turning radius if I remember correctly.
 
J2M2-J2M5 had maximum flap deflection of 50 degrees, but for combat it was 16 degrees.
Source : Model Art Issue 470 - Page 104 or Famous Airplanes of the World 061 - Mitsubishi Navy Interceptor (J2M) Raiden (Jack) - Page 14

Ki-43 had maximum flap deflection to 30 degrees with speed limit of 250 km/h , and combat deflection 15 degrees with speed limit of 400 km/h.
According to the source :
"6. The butterfly flaps were adopted to increase the performance in banking (turns). The performance is increased considerably by lowering the flaps 15 degrees. However, continuous use will create drag. The flaps operations in combat (Up-Down) are controlled by the flap selector control lever, or, electrically, by the control stick push buttons."
Source: References on piloting Type I Fighter, Model 2 issued on January 16th, 1943 by Army Air Inspection Dept, Akeno Army Flying School.

Ki-44 had maximum deflection of 35 degrees with speed limit of 250 km/h, 15 degrees for combat with speed limit of 400 km/h and 9 degrees up to 450 km/h.
Source is Ki-44 manual, but I dont have exact title translation.


N1K1 had a two stage flaps, to be precise it had a "master" flaps of fowler type which could be deflected up to 19 degrees and at the end of those there were "slave" flaps of standard split type which increased the overall deflection to 41 degrees. If I will find a picture, I can upload it if need be.
The performance of those was a decrease of turn radius by 20 % or even more, however the turn time did not improve as good as turn radius and usual turn time decreased by about 1 to 1.5 second.
The maximum lift-coefficient are approximetely as follows:

Aerial-combat flap at 0 degrees 1.7
Aerial-combat flap at 19 degrees 2.5

Source: Aviation report 0311 - Study of aerial-combat flap (Part 1), Model 15 prototype float seaplane fighter - issued in 1943.
 
Wow awesome information folks. You all really never cease to amaze me!!!
I really do appreciate all your knowledge.
 
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But why are you so interested in those flaps Jugggo ? Usually people debate speed, rate of climb or cockpit conditions (always that lack of cup holders makes me laugh) but flaps ? That is quite technical thing mate :)
 
You are correct those are the things most people debate about. :) but when I read test reports or pilots notes and they mention it but no data to back it up I usually go over board to find the answer :)) it is those little things that get my interest into researching more data.
 
Ha, this is feeling I know too. Good that there are more people interested in those little details !
 

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