DP 330 Ailerons Quick fix ? FOR fLutter
 

Had an idea to get some opinions on / As we all know on open structures 80-90 % on it's strength comes from the covering /

How would doubling the ultra coat on the bottom of the ailirons strenthen in torsion /Light weight and easy to do / most of us have the extra
covering from sealing hinge lines OR

Useing a fabric type under the ultracoat?

DO You THINK this will strengthen enough ?

IMO less hassle then extra servo install .

Reguardless it is important to keep the covering tight on the ailerons.and check them in hot weather !



Thanks Ron

Flutter
 

Here is an approach to diagnosing the flutter. Turn the radio on. Grab the aileron at the trailing edge closest to the aileron control horn and try to deflect the aileron. Observe what allows the aileron to deflect. Is it the wood of the aileron bending, the hinges giving, the control horn mounting, the pushrod, the servo gears or the servo mounting? Then grab the aileron near the tip and try to deflect it. Does the aileron twist before anything else gives? Correct the elastic part by making it stiffer. If the servo output is rotating under load, then a better (possibly digital) servo is needed.

BTW, although Monocoat is not the easiest to apply over solid balsa, it is far stiffer than Ultracoat. One ounce per square yard kevlar in laminating epoxy, with the threads running at 45 degrees to the length of the aileron, will impart more stiffness for weight than any other covering. It is necessary to completely encapsulate the wood to get the best results.

Reply
 

Ollie

I did te test before The thread !

What I found out was a little bending at the horn BUT
at the tips of the aileron was about 3/8th deflection each way with about 5 to 7lbs of force applied . This Is a built up aileron // open structure
design problem and is rather large ,making up /oh say 1/6th
of the area !

I would use monocoat if I could get a color match (not available)

I thought I might try To put the ultra over the ultra (much like doing a solid structure (just hard to keep bubles out !!!


PS The flexing accured in the wood and covering !

THANKS for input RON

Stiffen Aileron
 

If the covering doesn't do it for you, you can uncover the framework and tightly wrap spirals of kevlar tow saturated with laminating epoxy around the aileron. Each end of the tow can be glued to the franework with thin CA to keep it in place while the epoxy cures. Blot off the excess epoxy with paper towels. Make both spirals at 45 degrees to the length of the aileron and crossing each other at 90 degrees. Then recover with any convenient film covering. If you are fussy about bumps in the contour, you can recess the kevlar tow by sanding in minimum grooves in the framework to let the kevlar lie flush. The kevlar tow is only 1/8 inch wide and a few thousandths thick.

stiffer aileron
 

rctt

I have about the same flexibility on my ailerons. Let me know if covering the ailerons on the bottom has solved the flexing. Also include the technique on how you applied the extra coat of ultra. i plan on replacing the hinges with robart hinges also while in the process adding the extra coat.

thanks
Santi

Stiffen Aileron
 

Here is another thought. Remove the covering. reduce the thickness of the aileron by planing and sanding. Add 1/32 contest balsa sheet to both sides of the aileron. This will stiffen them without adding much weight. Use thin CA to harden the balsa where the horn mounts.

reply santi
 

Thanks for the sheeting idea Ollie !

To Santi / I Havn"t done the recover yet /I was throwing
The Idea around I will try to post when when and IF I go that route // Ollie had a great Idea just to sheet it !

thanks Rctt

DP 330 Ailerons Quick fix ? FOR fLutter
 

Micafilm is the strongest, stiffest covering material. Trouble is you have to paint it to colour match.

REVIEW
 

I did the covering job today on ailerons / I had purchased some off white coverite FABRIC and striped the old covering off bottom and replaced with coverite /NO GOOD /IT DID NOT IMPROVE the
stiffness ! I removed and tryed some monocoat white I had left over and covered it with the matching color ultra coat /
A NOTICABLE IMPROVMRNT !
The two layers AND ( as Ollie stated the mono is stiffer ) DOes Help it alot
Please NOTE it is a little hard to keep bubbles out //Just work it like a solid structure . I started at top center and work across //About a inch down across the whole lenth at a time//

The fabric was tough but just would not stretch tite enough !
It also was a low temp type !

I used 14 hinges each side and used a metal gear heavy duty
servos @ 100 in/oz plus// Use good hardware or evan better// beef up wood mount and bolt through ! as i did

I DOUBT I"LL HAVE AILERON FLUTTER BUT IF I DO I"LL POST//
JOB WAS NOT BAD AT ALL!

THANKS TO EVERY ONES IMPUT !

TOTAL JOB TIME 1 1/2 HOURS TAKING MY TIME/// 1 OZ added weight

re-covering job
 

rctt

I think that is great that it helped out with the flexibility. I have a couple of questions as I'm not a good builder. Do you think I will have to strip the ultracoat before I use some monocote? Would that be ideal? or can I cover it with the monocoat then again cover with the ultra? Thanks for all your help...

Santi

REPLY SANTI
 

YES you could If weight Is not an issue for you /
You are more likely to get more bubbles /best to only have two layers on .IMO

REPLY
 

HAY SANTI
I HAVE a another idea That would be easy/ look good/ and not to heavy / YOU COULD USE OBECHI WOOD SKINS AT 1/32 THICK
I THINK THESE WOULD BE THIN ENOUGH TO NOT NEED TO SAND
DOWN AILERONS /AND WOULD BE A LOT STRONGER

YOU WOULD PROBABLY HAVE TO ORDER// I KNOW OUR LOCAL HOBBY SHOP DON'T CARRY THEM /
GOOD LUCK RON