[TBrum]

My thought was for sound dampening more than changing the resonance frequency. The quads are soo smooth that I've never seen a vibration / resonance issue on any of the past quad-equipped planes. I was thinking sound dampening to muffle the intake noise... kinda like stuffing a airbox on a snowmobile.

That being said, stiffening up the cowl must also help!!

I have a 60cc 3DHS Edge that I notice the cowl resonates a fair bit so was thinking of experimenting on that first

[TBrum]

I'm pretty sure Brian out West sourced a lightweight foam for Henry Porium that was glued onto the cowl of Henry's 126" Carden/DA200 like what Brad suggested and I thought he said the difference was very noticeable.
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Guess I need to do some surfing tonight to locate those details on his FG thread!!

John... I like your idea of rolling on an expanding foam coating!!! Huuuuuumm!! The wheels are just turning like crazy here

[cravenjw]

Originally Posted by TBrum

I'm pretty sure Brian out West sourced a lightweight foam for Henry Porium that was glued onto the cowl of Henry's 126" Carden/DA200 like what Brad suggested and I thought he said the difference was very noticeable.
.
.
.
.
Guess I need to do some surfing tonight to locate those details on his FG thread!!

John... I like your idea of rolling on an expanding foam coating!!! Huuuuuumm!! The wheels are just turning like crazy here

Try a test with the stuff i have on hand. You have two running cowls that resonate. The edge and the yak55. Maybe try some adhesive foam tapes/sheet also.
Your carden with the brick might not resonate! The cowl has to have some surface of feature that is just right for the MVVS brick running at some given speed (or range of speeds). It might not happen!!! You might also add stuff, and then just shift the resonance to another frequency (ie motor rpm). The trick is to shift it out of the range of motor operation.
Personally, i wouldn't do it until its there. Meaning wait. Your just guessing at this point. But that's my two-cents worth.

[rpm]

Could some kind of stiffening rib (like a cowl ring) maybe made from carbon fibre or ply glued to the cowl, lengthwise and crosswise stop the flexing and thereby sound. I don't think it will help intake sound but I expect it suppress resonance from the cowl vibrating.

[Old School Flyer]

Originally Posted by TBrum

My thought was for sound dampening more than changing the resonance frequency. The quads are soo smooth that I've never seen a vibration / resonance issue on any of the past quad-equipped planes. I was thinking sound dampening to muffle the intake noise... kinda like stuffing a airbox on a snowmobile.

That being said, stiffening up the cowl must also help!!

I have a 60cc 3DHS Edge that I notice the cowl resonates a fair bit so was thinking of experimenting on that first

Great topic. Almost a thread of its own.
The lighter and thinner the more noise for sure.
I thought your 3d edge had da60 the racket that airframe made

[TBrum]

LOL!! A nice jab at the DA60!! Attaboy Hanes

I stiffened the cowl of my 3DHS Edge up with CF and it's much better now (was horrific on the first flight) but what you hear in that video is mostly the skiis of all our planes. The GP and EME are really nice and smooth.

Agreed John and Paul... I've never seen an issue with a Carden cowl and resonance issues... the cowls are pretty stiff and beefy. Even my ZDZ180 on the VW Edge and there was no issues. My intent was not to mess with anything resonance related, but to insulate to reduce intake noise so that we hear more the pipe sound. The quads are like sewing machines

Trev

[atc666]

Originally Posted by TBrum

Guess I need to do some surfing tonight to locate those details on his FG thread!!

Here is the link to the FG Build..

http://www.flyinggiants.com/forums/s...=71449&page=89

the stuff is from www.soundcoat.com

[TBrum]

Ah!! Thanks Adam!!!!

This is from Henry's thread on FG.....

I fly at a fairly noise sensitive field and I personally also like quite airplanes so I'm trying something new on this plane. A friend of mine, Brian M. sent me a few pieces of a sound dampening product called "Soundcoat", www.soundcoat.com
It is a foam material with a sticky back coating that you apply where ever to make what ever it is more quite! Anyway, I lined the inside of the cowl with it, hopefully it will dampen any noise coming from the carbs or the engine itself. I don't know if it will do much but we''ll find out.
I'm going to take DB readings from my old airplane and compare to this new one, both are set up exactly the same, should be interesting.
It came with a bit of a wieght penalty but if it works I'm happy to live with that, if not I can always pull it back out.

[TBrum]

I didn't feel like playing with foam or balsa tonight, so I got the cuffs fitted to the fuse and the light-ply plates shaped to fit the pants and Hysol'd in place.

This is where Hysol really shines and nothing will come close... wood to fiberglass

Tomorrow I'll get the Airman's installed and wheelpants on

[TBrum]

Last night I got the CF gear drilled, Airman wheels installed and wheel pants buttoned up. A nice little project to get out of the way now