Kyosho P-40 Flutter
10-11-2003 | 08:54 PM
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From: Marietta, GA
Kyosho P-40 Flutter
Hi all,
I had a Kyosho P-40 with an elevator flutter problem. It eventually led to the horizontal stabilizer breaking off in high speed flight. It happened twice. I was able to get it on the ground in one piece the first time, not so lucky the second time. My guess is that it might have been caused by the linkage. Wooden dowels with wire on each end were used. I noticed that when the servo traversed, the wire ends would bend. With the power off, I noticed that when moving the elevator by hand, the wire would bend a little before the servo moved. Could this be the culprit? I plan on building another, but with a little modification, like plastic tubes instead of the dowels, shimming the gear forward to taxi on grass and recovering with monokote. Has anyone done anything similar to this?
Thanks in advance,
Mike
I had a Kyosho P-40 with an elevator flutter problem. It eventually led to the horizontal stabilizer breaking off in high speed flight. It happened twice. I was able to get it on the ground in one piece the first time, not so lucky the second time. My guess is that it might have been caused by the linkage. Wooden dowels with wire on each end were used. I noticed that when the servo traversed, the wire ends would bend. With the power off, I noticed that when moving the elevator by hand, the wire would bend a little before the servo moved. Could this be the culprit? I plan on building another, but with a little modification, like plastic tubes instead of the dowels, shimming the gear forward to taxi on grass and recovering with monokote. Has anyone done anything similar to this?
Thanks in advance,
Mike
10-12-2003 | 07:05 AM
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From: west hartford,
CT
RE: Kyosho P-40 Flutter
You gett flutter from too much speed thats the culprit?? You can also put on a gap seal between the stab. and ele. to help but SLOW DOWN and it will stop
10-12-2003 | 07:24 AM
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From: West Aus, AUSTRALIA
RE: Kyosho P-40 Flutter
Your control rods flexing shouldn't be the cause of the flutter. CoG of your elevator (not the aircrafts CoG) needs to come forward towards the hinge or even in front of the hinge via a mass balance. Or you could slow down! 
10-12-2003 | 12:02 PM
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RE: Kyosho P-40 Flutter
I have the same set up on my Kyosho Zero, and no flutter at extreme speed (YS 63FZ). The elevator does have some play in it, but the play is not enough to cause flutter. Check your horizontal stab to see if it flexes. My buddy also has a Kyosho P-40, and bad wood was used in the horizontal stab. It flexed and vibrated so much that the covering cracked and popped.
10-12-2003 | 03:59 PM
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From: Marietta, GA
RE: Kyosho P-40 Flutter
Thanks guys for the advice.
Yes, there was quite a bit of flex in the horizontal stab. I plan on cutting a solid piece of balsa for the next one. I plan on pulling off that cheap covering anyway, so if there are any other weak areas, hopefully I'll notice. I plan on covering in pre WWII colors. (OD on top, gray on the bottom) Right now I'm looking for a decal set with the white star/red dot and U.S. ARMY for the bottom. Knowing my luck, TF will have a P-40 ARF by the time I finish with this project.
Mike
Yes, there was quite a bit of flex in the horizontal stab. I plan on cutting a solid piece of balsa for the next one. I plan on pulling off that cheap covering anyway, so if there are any other weak areas, hopefully I'll notice. I plan on covering in pre WWII colors. (OD on top, gray on the bottom) Right now I'm looking for a decal set with the white star/red dot and U.S. ARMY for the bottom. Knowing my luck, TF will have a P-40 ARF by the time I finish with this project.
Mike
