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Flutter Kills

Old 05-03-2004, 02:04 PM
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barkin_bob
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Default Flutter Kills

Hi guys thought i would share some photo's of the results from severe flutter. I was doing a full speed fly by when the rudder started to flutter, so bad that it snapped the control horn. The plane would not respond to elevator input and down she went. Damage was minimal because of low angle of approach. I've put dowels in the rudder in my other spads but forgot to put them in this one. We learn from our mistakes.
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Old 05-03-2004, 09:02 PM
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fearlessJOE
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Default RE: Flutter Kills

I lost a sig wonder in a similar crash. fluttered the elev. the plane went in STEEP, 45 degrees or so. No damage at all to the plane. stripped a futaba 3004. Broke the prop. had witnesses too. No bull![8D]
Old 05-04-2004, 01:18 AM
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Default RE: Flutter Kills

Bummer Put dowls in the debs tail feathers and ailerons last week. Tried it out today and its much more responsive. Gotta rebalance it alittle though its just a tad light in the nose now.

Stuffed the FNS today, tried a real low inverted pass. Then I pulled up[X(], yup thats right I pulled back on the stick while inverted.[:@] FWAPP! Only damage was broken prop as usual and snapped the nylon motor mount clean in half. Would you believe the wing didn't even pop off. Plane was undamaged but muddy. Spent most of the repair time cleaning mudd off the engine,lol.

That makes 12 flights and 3 crashes and shes still looks and flys great. Luv them SPADS
Old 05-07-2004, 12:12 PM
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Default RE: Flutter Kills

My first spad flying wing fluttered and crashed in the first flight . After that and many flights and 3 spads designs I learned this:

1) Use a control horn that is installed as close as possible at the center of the moving surface.
2) Use a control horn that is anchored at many flutes as possible, ex. use a L - shaped aluminium horn with a aluminiun base at the other side of the coroplast.
3) Use a low-pitched prop
4) Use 4-40 hardware to avoid linkage binding
5) Taper the tips of the moving surfaces
6) When designing a new model ,try to keep the rudders , elevators, wings at a low aspect ratio.
7) Avoid designing ultra-fast prop planes with coroplast, Keep the coroplast to make moderate-speed models or 3D types.

Hope that my experience would help, Regards, Enrique
Old 05-11-2004, 07:01 AM
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Capn America
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Default RE: Flutter Kills

I lost mine last week to flutter. I was flying inverted at high speed when you could hear it start to flap. I rolled it over and banked it around to land but it had already broken one of the two v-tail servo horns. Turned it right down into the dirt. I can still reuse the wing and tail but the fuse needs to be remade and the os 61 lost the remote needel mount in the crash. Ive been flying the devistator with the 61 and a 12-6 prop. Thing really screams.
Old 05-11-2004, 08:35 PM
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Default RE: Flutter Kills

HIYA Bob.
How's things up north??
Old 05-11-2004, 09:33 PM
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Default RE: Flutter Kills

Flyin, crashin,flyin, and flyin and havin lot's of fun doin it .
Old 05-12-2004, 08:52 AM
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Default RE: Flutter Kills

My first BUHOR had bad flutter. Come to find out the elevator had slightly warped and was flapping at high speeds. I have since learned to stiffen up everything with as many screws and plastic as possible.
Old 05-12-2004, 04:46 PM
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Default RE: Flutter Kills

Ive actually found that most of my flutter and buzzing sound was from the holes in the pvc control horns haveing to much play around the z conecters. Im useing the plastic durobro quick connects now and they work good. I like the fact they pop off on crashes instead of messing up my servos. I also use a small piece of fuel line around them so they dont pop loose durring high stress turns.
Old 05-12-2004, 06:11 PM
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Default RE: Flutter Kills

Here's a cure for my Bandit
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Old 05-12-2004, 10:46 PM
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Default RE: Flutter Kills

Is that wire?
Old 05-15-2004, 04:38 AM
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Default RE: Flutter Kills

Yes it's #2 metal rod and solder on electical connector's with 4-40 bolts
Old 05-16-2004, 06:58 PM
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Default RE: Flutter Kills

Hey All......

On my first large (96" wing) SPAD (I called it the Dragon Fly) the horizontal stab was 30" and the vertical was 15" and made out of the 4mm coroplast. The only thing I did to reenforce it was to add dowels to the flutes about every 3". I had terrible flutter on any speeds over half throttle. It was suggested to me that I try flying wires. The first ones I made were from 14 gauge aluminum welding rod. It worked great except that the rod kept warping. This plane was used at our annual Fun Fly as a paintball target and no longer exists. ... It did it's job well and was a good death......

The second large plane I build was a blown up version of the SPADET (92" wing). The horizontal now 26" and vertical 14". This time I tapered the ends of the rudder and elevator slightly. I used thin nylon cord for the flying wires instead of the rod. Now I have a great flying plane......

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