Kawanishi N1K2-J Shiden Kai automatic flaps system

[Hiromachi 8,004]

2 days ago, on a Q&A sessions I’ve asked Devs  about the very specific feature, existing in N1K1 and N1K2 George – system allowing to automatically change the position of a flaps in response to a plane maneuvers.

Devs said that they will make some research and keep an eye on this feature.

In that case I’d like to share all the information I have about this system.

 

 

Basically, unique feature of the N1K2-J was its set of combat flaps. Whereas the flap extension was manually controlled on the Kyofu seaplane or Ki-43 Hayabusa (on a joystick pilot had two buttons, to manually switch flaps), the flaps on the Shiden-Kai  had the ability automatically to change their angle in response to changes in g-forces during maneuvers. This automatic operation freed up the pilot from having to worry about his flaps during combat, and eliminated the possibility of a stall at an inopportune time.

 

 

Those were single Fowler flaps, the maximal inclination of flaps was up to 30^o.

 

The mechanism was pretty easy and work on such dependence :

 

CL = nW / SPd

 

Where CL is a lift coefficient, n is a load factor, W is weight, S is bearing surface and Pd is a dynamic pressure.

Additionally if Pd = ro v^2 / 2, where ro is air density and V is flight speed. As we know ro is constant for given altitude, than Pd depends only on a flight speed.

 

 

Of course pressure depends also on a flight altitude.

 

As the W and S are constant, than Cl depends only on a load factor n and dynamic pressure Pd. As the head of mercury h in utensil correspond with Pd/n rate, than Cl depends only on a h value.

 

But what was exact shift of  cam, moving the flaps – on what angle the flaps were moving, I have no idea. 

Mechanism

 

 

flaps mechanism

 

I only have some materials from the tests made (post war probably).

 N1K2-J full turn without using combat flaps could perform in 200 m, when the automatic system was turned on and flaps were working the plane could make a full turn in 140m.

For a small comparison I also have a data for a A6M5 Reisen – Zero could make a full turn without using flaps in 144 m, and with flaps deployed in 114m.

And main competitor – P-51D was able to make a full turn without flaps in 260m, with flaps deployed in 211 m.

 

m – meters

 

I know that Wikipedia is mostly avoided, and considered as “non-source”. Basically I could agree with that in terms of English Wikipedia.

But I’ve found on a Japanese Wikipedia - 

http://ja.wikipedia.org/wiki/%E8%87%AA%E5%8B%95%E7%A9%BA%E6%88%A6%E3%83%95%E3%83%A9%E3%83%83%E3%83%97

Whole material describing the mechanism, I’ve used “google translate” to understand it (or at least try) and I think it is quite good. If you could look at it, would be nice.

 

 

Sources :

a)  Kawanishi N1K2 Shiden Kai – Krzysztof Zalewski

b) 最後の戦闘機 紫電改―起死回生に賭けた男たちの戦い – Ikari Yoshiro

c) Famous Airplanes of the World 53 - Kawanishi N1K Kyofu, Shiden, Shiden-Kai

d) Genda's Blade: 343 Kokutai - Japan's Squadron of Aces

 

 

At last I like to appologise for a quality of translation, some things (like those physical effects and factors) are hard to translate if you barely understand them – I’m a law student, not airplane constructor. If I’ve made somewhere mistake, please feel free to inform me.

 

@Posted as you've suggested Auscam.

[Windows_98 331]

:3 <3 :kamikadze:

[Katsukai 6,157]

[Hiromachi 8,004]

Guys, less spam please. It's more a topic for devs with data, than discussion place.

 

If you have any data, feel free to post but dont make it another spam topic, please.

[Windows_98 331]

haha, my bad; very good work. wish i could find anything usefull in the few books i have, but sadly not much usefull info, and i have this book that weighs at least 10 pounds. of ww2 planes sadly no good information in there lol..

[Guest]

While searching for informations about Shiden-Kai I found something interesting: Japanese test report on N1K1 combat flaps performance: [attachment=106264:Kugiho Vol. 0358.pdf]

[Viktor_E 2,121]

I think the most difficult question is how Gaijin is going to implement this feature. In WT flaps are completely automated at the flip of a switch and with the player normally using a simplified control system it would be hard to make the auto flap system work and shine.

[cfracas 1,708]

After Reppu BR increase and N1K1 floatplane introduction in game, this discussion needs to receive more focus.

I think all the technical data gathered should be merged into an official bug fixing request.

If anyone has scans of book pages with data about these automatic combat flaps, those should become part of such bug fixing request.

[fufubear 6,705]

It will never come to this game

[SaintPonPon 13]

uup 

[s9723 508]

It’s sad that Hiromachi has gone to il-2 BOX series as tester. GJ should value  good contributor and their opinion more……

[PuKi 140]

19 minutes ago, s9723 said:

It’s sad that Hiromachi has gone to il-2 BOX series as tester. GJ should value  good contributor and their opinion more……

Gaijin is trash in developing matter, they re like EA but russians. They totally destroyed a nice core game. They ban all arround and doesnt listen to players that want fixes before content. Cause of that good player base is leaving.

[Hopit 4,416]

Gaijin has some issues sure, but banning without a reason is not one of them

[nelsondx 958]

On 27/11/2017 at 4:28 PM, PuKi said:

Gaijin is trash in developing matter, they re like EA but russians. They totally destroyed a nice core game. They ban all arround and doesnt listen to players that want fixes before content. Cause of that good player base is leaving.

And mind you I've been here for almost 3 years, Gaijin changed a lot and they are FAR MORE friendly and are more willing to listen to the community. Sure they could've made some mistakes, it's only natural they are humans, not robots. I remember seeing 50.000 players tops, now I see 75.000. So I'm asking you, how did a good amount of player base left the game?

Plus I find it hard to believe they banned players for nothing.

Edited December 5, 2017 by nelsondx

[Spindash64 1,244]

What other aircraft had the Mercury switches?  I can't imagine they would only put them on the Shiden.

maybe if we get them, it'll be a whole avionics and control systems focused update.  Radar for night fighters and stuff, which is another major feature missing from many planes.

[MSGKI_HARA_UOOH 2,828]

3 hours ago, Spindash64 said:

What other aircraft had the Mercury switches?  I can't imagine they would only put them on the Shiden.

maybe if we get them, it'll be a whole avionics and control systems focused update.  Radar for night fighters and stuff, which is another major feature missing from many planes.

whats mercury switches?

[the_suztown 2,508]

6 hours ago, Samuel_Hyde said:

whats mercury switches?

It was the system that worked the automatic flaps, more G force more compression on the Mercury meaning the flaps would extend more.

 

it's pretty much all in the OP

Edited August 6, 2018 by the_suztown

[fufubear 6,705]

20 hours ago, Spindash64 said:

What other aircraft had the Mercury switches?  I can't imagine they would only put them on the Shiden.

maybe if we get them, it'll be a whole avionics and control systems focused update.  Radar for night fighters and stuff, which is another major feature missing from many planes.

A7m also had it.

[tester188@psn 1,413]

Here is the experimental data on the automatic combat flaps of N1K1 Kyofu (Allied codename: Rex).

Spoiler

 

 

Translation No. 38, 7 February 1945, technical items concerning aircraft and aircraft engines. Report No. 3-d(30), USSBS Index Section 6. Frame Number 56-67.

http://dl.ndl.go.jp/info:ndljp/pid/4009485/56?itemId=info%3Andljp%2Fpid%2F4009485&amp;contentNo=56&amp;__lang=en

 

N1K1 Kyofu equipped with automatic combat flaps because IJN required superior maneuverability equivalent to A6M2-N. Can I submit a bug report "N1K1 Kyofu missing automatic combat flaps" to the developer with this document as a source? 

 

An excellent player posted the manual of N1K1-J's automatic combat flaps in the suggestion section.

 

[PickleJarOfDeath 1,498]

On 05/08/2018 at 13:34, Spindash64 said:

What other aircraft had the Mercury switches?  I can't imagine they would only put them on the Shiden.

maybe if we get them, it'll be a whole avionics and control systems focused update.  Radar for night fighters and stuff, which is another major feature missing from many planes.

This is all meant to pave the way for tier 6 aircraft. The earliest we could see tier 6 in any form would be 1.83 because they want to have these systems in place to have issues spotted by players, collect data, and iron out the issues. That would be the perfect patch to introduce full functionality to all aircraft. The P-61 lockable turret is another example. More of a sim thing but many US bombers had  rudimentary autopilot stabilizer systems which did not rely on lining up trim tabs. Obviously you would have them in a logical position but the stabilizer further adjusted controls. I could imagine the late War US cruise missiles or whatever they were. Can we have pigeon guided missiles? Germany had developed magnetic gunsights and photosensitive triggers. The magnetic gunsights would “sense” aircraft that were lined up with the guns and close enough. This automatically would fire the guns. I’d guess this is really short range. They weren’t radar systems so I’d expect poor range. This would be great for sim. It would make crazy snapshots really easy and not sparky/painful. The photosensitive triggered schräge musik configured rockets and cannons would be interesting. They were less practical but I could see them having their place. Russia had hand painted windscreen gunsights. I mean crosshairs. That would be cool. ))))) Russia didn’t have much in the way of technology beyond purely practical design given that they needed a lot of flexibility in terms of manufacturing during the war. Britain probably had similar things to the US for its bombers. The Welkin had a hella T H I C C wing aspect ratio. That’s pretty crazy. It had “a sophisticated electrical system” so that’s cool. Honestly I cannot find much else aside from the bombers though. Japan as we know has ^^^this^^^… France really drew the stub fragment from the short end of the stick in the war and doesn’t have much in the way of special stuff… Italy had unsealed cockpits the whole way through so there is no hope for them. Sorry. There is a lot of stuff that could come alongside radar. There is a lot in the radar category alone that is interesting.

Edited August 10, 2018 by PickleJarOfDeath

[cricket27 164]

I think that this is definitely necessary for War Thunder. It would be very good for dogfights too. Nice thread!

[Spindash64 1,244]

On 06/08/2018 at 12:23, fufubear said:

A7m also had it.

I know I'm late in my reply again, but GIB