Any Aerodynamicists here?

[Jim H]

Good morning , a long shot I appreciate.

I’m looking for any advice relating to aviation aero. Ok, it regards a model Radio Controlled aircraft, however the fundamentals surely apply.

I had a huge crash with one of my RC aircraft this week, and I believe the source could be flutter associated with the design.

Basically the elevator servo failed, resulting in total loss of pitch. However, I consider it to be an aero imbalance in the design, which resulted in the failure of the servo.

Rather than single component failure and poor installation off.

I’m trying to understand horizontal stabiliser (tail plane) positioning relative to the trailing edge of the wing axis.

TIA

[Simpo Two]

I believe in real life control surface flutter is addressed by weights or dampers.

You might find something relevant at https://www.rcgroups.com/forums/showthread.php?108...

[Jim H]

Good afternoon Simpo. I do hope all is well with you?

I originally posted this in the Scale Models section.
I’m a member on the RCM&E forum where I posted, about this very issue.

Some very informative posts there, which are kinda supportive of my suspicion..

You never know? Adrian Newey might have a look over this forum ( anyone got his WhatsApp)?

I mean? Dafter things have happened ..

Plato popping up with a tin of custard..

[DeejRC]

Hi Jim. If you can, see if Pete Rieden is still around on that forum, also goes by PDR. He certainly used to be, but I grant you it’s been a while since I was in touch with him. He will almost certainly be able to sort you out, if anybody can on there it’s him - we are old Messybeast colleagues. If you get no joy ping me a msg via here with some more details and I’ll see what I can do. Fair warning though I’m swamped by work and I go on holiday end of next week!

[Jim H]

DeejRC said:

Hi Jim. If you can, see if Pete Rieden is still around on that forum, also goes by PDR. He certainly used to be, but I grant you it s been a while since I was in touch with him. He will almost certainly be able to sort you out, if anybody can on there it s him - we are old Messybeast colleagues. If you get no joy ping me a msg via here with some more details and I ll see what I can do. Fair warning though I m swamped by work and I go on holiday end of next week!

Hello sir, thank you ever so much for your reply. I’m on holiday myself. I will PM you.

[xeny]

Jim H said:

Basically the elevator servo failed, resulting in total loss of pitch. However, I consider it to be an aero imbalance in the design, which resulted in the failure of the servo.

What was the control linkage? Pushrods offer negligible damping and can themselves resonate, while cable in tube tends to inherently offer a decent amount of frictional damping.

[Jim H]

Hello Sir.

It was a massively “ Beefy” pushrod.

It’s very interesting you mention this. I had been thinking along the same lines.

It’s a Delta wing on this model. And it flys very quick.
I think there is so much disturbed air coming off the wing. Colliding with the tail plane.

I’m getting educated all the time about this. The elevator has no end points (distribute) the flow of air crashing into to it.