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Adam

Well Known Member
Well I'm on my 5th hour of flight and I came a cross a small problem. Some times, not all the times I get a loud Very loud buzzing sound from what I think is the rear of the canopy. It tends to happen when it is cold and I have the heat on. When I turn the heat off sound go's away. My canopy is very tight and so is aircraft. Do I need a vent? and has anyone else had this problem.
 
Adam,

It sounds OT me like you are changing the amount of air that has to get out when you open the heat duct (that's pretty obvious, I know...). That means you might have more air escaping under the canopy skirt - I don't think it is possible to stop it all - it acts as a one-way "out" flapper valve). DO you have some felt on the inside edge of the skirt, where it meets the fuselage? Many people have reported a loud buzzing from the canopy without it - glue on some felt seals, and it goes away. I'm sure the skirt is still vibrating, but it just doesn't make the racket with the felt there.

If you've already got the felt, then you've got a new mystery.....

Paul
 
I had a loud buzzing noise in my RV-6 during the first few flights. Not often, but every now and then it would make my heart race. Turns out it was my headphones touching the canopy - the vibration was translating into my skull.

Laughed out loud when I figured it out (and I'm embarassed to say I didn't catch it right away).:eek:
 
I had buzzing during colder periods also. Scared the tar out of me the first couple of times. (We don't get much cold weather down here) I isolated the location by slipping the plane and noticing which side was noisy and which side was quiet.

I bought some foam insulation with adhesive backing on the aviation isle of the local hardware store. I think it was 1/4" x 1/8" and installed it about 1" up from the bottom edge of the canopy. The first couple of times you close the canopy, it will be very tight but the foam will compress and find a natural set. I replace it at the annual condition inspection.

Karl
 
I have flown two 8s and both had the canopy buzz problem. It would show up at random airspeeds on both. They both sealed the skirt with foam insulation and the problem went away. Don
 
...ditto what Paul said. I could control the volume of the buzzing by opening and closing the front and rear air vents. Cut sticky-backed moleskin from the drug store into strips and lined the inside of the canopy skirt.
 
Ditto

I had a loud buzz one day and my friend and multiple RV builder, reached back there and pushed up on the canopy frame and the tune changed. As he pushed and let go it went WOOOOW...wooow....WOOOOW...woooow in rhythm with his pushing. Felt around the skirt fixed it all.

Regards,
 
Thanks for the replies seems like I need foam on the aft canopy, Ill let you know how I make out.
 
I've got the canopy buzz too, but only (so far) at higher speeds (close to the yellow band on ASI). If I push on the left rudder it goes away, right rudder it is worse. Has anyone tried using a strip of the fuzzy velcro as a seal? Think I may try that but if someone's been there, done that and it didn't work I'll try something else.
 
flickroll said:
I've got the canopy buzz too, but only (so far) at higher speeds (close to the yellow band on ASI). If I push on the left rudder it goes away, right rudder it is worse. Has anyone tried using a strip of the fuzzy velcro as a seal? Think I may try that but if someone's been there, done that and it didn't work I'll try something else.
Click to expand...

I'd think that fuzzy Velcro would work fine Jim - I used felt glued on with spray adhesive - still there after 916.7 hours! I don't think I would have needed th extra thickness of Velcro - the felt is pretty thin, and I had a good fit to begin with (not sure how that happened....)

Paul
 
Pierre,

give us those wind noise sounds again.

I'm having a hard time vocalizing those.



sorry, I couldn't resist.
 
This afternoon I finally got around to installing the fuzzy velcro, the self stick variety. Canopy buzz is goooooone...... I think the felt strip is actually the way to go cuz it probably looks better, but I would think in order to get a good job gluing down the felt the canopy needs to be off the airplane. So I'll use the self stick velcro for now, and the next time the canopy is off change it out to felt.
 
Canopy

I'm on hour 4 flight testing and right at about 160 kts indicated I start to hear the buzz. I looked back and I figured it was my canopy. The very back of my skirt sits about about 1/8" off the fuse,(when I built it it was right on but now it has somehow shifted and lifted), anyway, I'm going to try the foam...sounds like thats the "trick".

Chris
 
I have had a louder-then-I-like-it-to-be bang once in a while that could not figure out what it was and each inspection of the interior/exterior yielded no clue, till one day I found it. It turned out that my pee bottle or any empty water bottle in the luggage compartment gets squeezed from low pressure and make that laud noise, phew a sigh of relief.
 
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