Flutter - How to find the cause??
09-18-2015, 04:31 PM
#76
11-15-2015, 07:07 AM
#77
Thread Starter
About a month back I replaced the hinges on the ailerons with the CA mylar type hinges. After some test flights the flutter was completely gone. I could fly as fast and as hard as I wanted with no flutter. However this led me to being to brave with it and end in a bad crash that completely destroyed it.
Last edited by A. J. Clark; 11-15-2015 at 07:13 AM.
11-20-2015, 06:59 AM
#79
Join Date: Dec 2001
Location: Upplands Vasby, SWEDEN
Posts: 7,816
Likes: 0
Received 3 Likes
on
3 Posts
Hi!
AS "Speed" and I said earlier! Flutter is nearly always coming from the ailerons on sport planes having long strip ailerons! Why!
Because the outher part of those strip ailerons are so easy to twist and it's there the pressure differences between the under side of the wing and upper side meets creating a vortex that is trying to twist the wing structure.
No mass balancing is necessary on any well built model plane! The only thing to follow is to build planes with stiff and sturdy wings, stabilizers and rudder surfaces and having strong servos and stiff linkages. Also important is to follow the general rule of thumb using as short servo arms as possible and as long aileron/elevator arm as possible. And of course...no strip ailerons all the way out to the wing tip!
Of course flutter could occur on the elevators as well but it's my experience from flying for 40 years that this is not as common as aileron flutter.
The goal is to have the elevator surfaces/linkages so stiff that when you push with your fingers on top of the surfaces no deflection at all should occur.
AS "Speed" and I said earlier! Flutter is nearly always coming from the ailerons on sport planes having long strip ailerons! Why!
Because the outher part of those strip ailerons are so easy to twist and it's there the pressure differences between the under side of the wing and upper side meets creating a vortex that is trying to twist the wing structure.
No mass balancing is necessary on any well built model plane! The only thing to follow is to build planes with stiff and sturdy wings, stabilizers and rudder surfaces and having strong servos and stiff linkages. Also important is to follow the general rule of thumb using as short servo arms as possible and as long aileron/elevator arm as possible. And of course...no strip ailerons all the way out to the wing tip!
Of course flutter could occur on the elevators as well but it's my experience from flying for 40 years that this is not as common as aileron flutter.
The goal is to have the elevator surfaces/linkages so stiff that when you push with your fingers on top of the surfaces no deflection at all should occur.
Last edited by jaka; 11-20-2015 at 07:30 AM.
