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Author Topic: Japanese W II RC Models  (Read 33642 times)

Offline Jemiba

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Re: Japanese W II RC Models
« Reply #15 on: November 26, 2013, 09:34:34 am »
A
In the flying world we say 'Holm- und Rippenbruch', ...

Ah, ok ! It will be the model that is hurt, not the pilot in most cases ! ;)
It takes a long time, before all mistakes are made ...

Offline blackkite

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Re: Japanese W II RC Models
« Reply #16 on: November 26, 2013, 06:05:46 pm »
Oh Josef did it!!!!!! :o Be careful in take off.
« Last Edit: November 26, 2013, 06:20:19 pm by blackkite »

Offline hartmutbehrendt

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Re: Japanese W II RC Models
« Reply #17 on: November 27, 2013, 10:38:08 am »
 :'(Hi Blackkite, Josef and me we know this video already, thank you. We are thinking about the circumstances for the crash. This video is the reason that Josef has delayed the first flight of his Shinden. He plans to built a smaller Shinden first to try the behavior. I myself I think that the area before the CG, seen from the side view, is greater than the area behind, the crash shows typical indizes for this matter, Hartmut
« Last Edit: November 27, 2013, 04:04:12 pm by hartmutbehrendt »
Hartmut

Offline Jemiba

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Re: Japanese W II RC Models
« Reply #18 on: November 27, 2013, 10:52:56 am »
..the area before the CG, seen from the side view, is greater than the area behind, ..

Wouldn't this just result in a dive ? But the model obvious flipped inverted.
It takes a long time, before all mistakes are made ...

Offline blackkite

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Re: Japanese W II RC Models
« Reply #19 on: November 27, 2013, 03:39:35 pm »
:'(Hi Blackkite, Josef and me we know this video already, thank you. We are thinking about the circumstances for the crash. This video is the reason that josef has delayed the first flight of his Shinden. He plans to built a smaller Shinden first to try the behavior. I myself I think that the area before the CG, seen from the side view, is greater than the area behind, the crash showes typical indizes for this matter, Hartmut
Oh clever approach! Good luck to you. :D
« Last Edit: November 27, 2013, 03:41:28 pm by blackkite »

Offline hartmutbehrendt

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Re: Japanese W II RC Models
« Reply #20 on: November 27, 2013, 03:58:17 pm »
Hello Jemiba,
I don't mean nose heavy around the transverse axis: If the Square meter before the CG is higher than after the CG, seen from the side of the model, the vertical stabilization around the vertical axis failes. The plane looses the direction, and while the airstream comes more and more from the side, the wing will swing up or down immediately and turns the whole plane to be inverted. I know this already because I had a model with this situation. The model did roll so quickly I could'nt even react at all.
« Last Edit: November 27, 2013, 04:06:11 pm by hartmutbehrendt »
Hartmut

Offline blackkite

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Re: Japanese W II RC Models
« Reply #21 on: November 27, 2013, 09:16:00 pm »
I imagine that,
Excessive pull up after take off ⇒Front wing stall because of high angle of attack ⇒ Lost front wing lift ⇒ Nose down ⇒ Dive ⇒ Crush
Should the model airplane be raised little by little?
 
« Last Edit: November 28, 2013, 02:37:39 am by blackkite »

Offline Jemiba

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Re: Japanese W II RC Models
« Reply #22 on: November 28, 2013, 12:54:46 am »
...If the Square meter before the CG is higher than after the CG, seen from the side of the model, the vertical stabilization around the vertical axis failes.

Ok, think I got it now. Even slight disturbances are enough then for losing conrol. Somewhat glad, that I'm flying
"Schaumwaffeln" at best. Couldn't stand losing such a model !  :-\
It takes a long time, before all mistakes are made ...

Offline blackkite

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Re: Japanese W II RC Models
« Reply #23 on: November 28, 2013, 03:46:41 am »
Hi! Finally right roll by propeller torque.
« Last Edit: November 28, 2013, 09:44:43 pm by blackkite »

Offline blackkite

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Re: Japanese W II RC Models
« Reply #24 on: December 01, 2013, 03:38:53 pm »
 The scene of touchdown of a model airplane was cut by edit in this video.
When watch the model airplane after landing, we realize that the door of a front wheel and a front wheel were damaged.
I imagine that the model airplane carried out hard landing by rapid nose down.
If this model airplane's angle of attack becomes large at a low speed, front wing stall and generate rapid head lowering occur this airplane? Didn't the IJN(Kugisho) know this tendency through the flight of MXY-6?


 
« Last Edit: December 01, 2013, 03:45:34 pm by blackkite »

Offline blackkite

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Offline blackkite

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Re: Japanese W II RC Models
« Reply #26 on: December 02, 2013, 04:54:52 am »
Shinden front wing had retractable leading edge slat and double flap/elevator.
Shinden's main wing was made by thick plate with welded stiffner (without small rib).
« Last Edit: December 02, 2013, 05:04:31 am by blackkite »

Offline Jemiba

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Re: Japanese W II RC Models
« Reply #27 on: December 02, 2013, 09:00:07 am »

If this model airplane's angle of attack becomes large at a low speed, front wing stall and generate rapid head lowering occur this airplane?

That's what principally makes a canard layout unstallable. At least the worst consequence, that can hapen to a conventional
aircraft, just plunging down tail first, cannot happen, as it would drop the nose and gather speed again. Of course that doesn't
mean totally vice free flying characteristics.   :-\
It takes a long time, before all mistakes are made ...

Offline Bill Walker

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Re: Japanese W II RC Models
« Reply #28 on: December 02, 2013, 11:49:25 am »
This depends on your definition of "stall".  The main wing of a canard design is hard (but not impossible) to stall.  The aircraft may have rotational momentum in the pitch axis at the time the foreplane stalls, allowing it to continue briefly pitching nose up, enough to stall the main wing.

Stalling the foreplane can result in a loss of pitch control that can only be overcome by changing the pitch.  This is a bad situation to be in.  You hope that the stall of the foreplane is accompanied by a nose drop, but it may not always be so, or it may not always be fast enough, or it may be too fast.  Also note that if the nose pitches down to unstall the foreplane you are also reducing the lift coefficient of the main wing, at a time when you may not want to do this.  Consider a foreplane stall on short final.  An uncontrolled nose drop plus a loss of lift is probably not a good thing at that point. 

I suspect this is part of the reason for the slats and double flaps on the Shinden canard.  Stalling the foreplane before the mainplane is not desirable.
Bill Walker

Offline blackkite

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Re: Japanese W II RC Models
« Reply #29 on: December 02, 2013, 04:10:28 pm »
This depends on your definition of "stall".  The main wing of a canard design is hard (but not impossible) to stall.  The aircraft may have rotational momentum in the pitch axis at the time the foreplane stalls, allowing it to continue briefly pitching nose up, enough to stall the main wing.

Stalling the foreplane can result in a loss of pitch control that can only be overcome by changing the pitch.  This is a bad situation to be in.  You hope that the stall of the foreplane is accompanied by a nose drop, but it may not always be so, or it may not always be fast enough, or it may be too fast.  Also note that if the nose pitches down to unstall the foreplane you are also reducing the lift coefficient of the main wing, at a time when you may not want to do this.  Consider a foreplane stall on short final.  An uncontrolled nose drop plus a loss of lift is probably not a good thing at that point. 

I suspect this is part of the reason for the slats and double flaps on the Shinden canard.  Stalling the foreplane before the mainplane is not desirable.
Thanks a lot. Your explanation is little hard for me. I need more study about canard aircraft flight chracteristic.
Please show me your opinion about the reason why one Shinden RC model failed to take off and Japanese Shinden RC model failed soft landing. 
The reason for take off failure was the posion of C.G.?
http://adamone.rchomepage.com/cg_canard.htm
 
« Last Edit: December 02, 2013, 04:21:44 pm by blackkite »