Diabolic
 

Joe,

Have you had any issues with the flying stab on the Diabolic.

I flew mine today and the flutter was so much that I could not fly over 1/4 throttle (15x4 prop).

Did you have to do anything special to balance the elevator/stab?

How much play do you have in it?

Thanks,

Eric

Diabolic
 

I'm just building one and I'm using a Hitec 5245MG, this servo has almost no backlash and the holding power is tremendous, but which servo did you use on the stab?, could that be the cause of your flutter?

Diabolic flutter
 

I had the same thing. The cause is not the servo, it is due to having to reduce the size of the carbon rod to fit through the bearing holders. Then the rod is too small and you have lots of slop. Good idea, POOR DESIGN!
Bob

Diabolic
 

I have one too. I am using this plane for demo flight, but the elevator is slop free.
I am running very heavy electric set up. (8lbs.)
Hacker B50 11XL w/5.2:1 gearbox, 20 cells and 20x11 prop.
Unlimited vertical.
It's interesting some people are having problems other not, as a distributor I wouls like to know the reason.
We also got some very interesting videos.
If somebody wants them, just drop me an email.

Eohlin: Did you do something with the CC rod?

CC spar
 

One more thing the CC rod has to be glued to the ball bearings.
I used thick CA glue in order to do that.

Check out this post
 

"Small 3D planes........... It's about the Diabolic.

My Flying stab
 

I've never had flutter in mine.

Setup: JR 8411 with CF pushrod.

The 8411 is a very strong servo, yet notorious for having slop in the geartrain. Yet my stab has not fluttered.

At one point (after about 50 flights) my plane started to oscilate in pitch over 1/4 throttle. It was a porpoising motion. I found the set screw at the stabilizer horn had come loose. Once I tighted this (and put ca on it so it couldn't loosen again) I had no more problems.

It is a uniquely flying plane. Hope you sort out the problem with yours and enjoy it.


BTW although there is a very small amount of play in the cf spar/bb joint I have not noticed any adverse effects.

Joe

Diabolic
 

So should I glue the stab spart to the bearings?

Excuse my ignorance, but...
 

Whar does spart mean :confused:

Diabolic
 

Sorry, I mean stab spar

AHhh HAaaa
 

I thought it was something in another language ;)

Diabolic
 

Nope, it was just interference between the brain and the finger.

Diabolic Flutter
 

I have a Hitec 645 on the elevator with the Carbon Fiber puch rod and ball links on both sides. The servo arm is the Dubro HD long arm that give the appropriate movement for full deflection.

The problem seems to be the amount of play in the Carbon spar going through the bearings. I CAed the bearings to the plastic bushings, however I did not CA the Spar to the bearings...this must be my problem?

I did nothing to the Spar itself. It does have a significant amount of play.

Thanks for all the help.

Eric