Help me figure out a noise.... - Page 2

rocketbob · #11 11-09-2018, 05:01 AM

Crank seal will sometimes whine as it starts to go bad. Noise will change with RPM. More like a faint squeal.

strahler13 · #12 11-09-2018, 05:58 AM

Does it change with changing cabin vent openings? Try yawing plane form side to side to change noise. Guessing canopy seal.

Mark

bhester · #13 11-09-2018, 10:41 AM

When I picked up my plane after getting it painted, I had a whine noise that I did not have before getting it painted, it was pretty loud.
I accidently found it when I started feeling around for air leaks. I put my fingers in the area right between the canopy rail and the canopy skirt right beside me and the noise went away. The bottom pilot side canopy skirt was bent outward near the front just enough to cause the air to whistle or whine while in flight. I messaged the skin inward in that area and it has never whined again. It was caused by the canopy sitting on the table while it was off during the painting process. So check that area on both sides.

Phil · #14 11-09-2018, 10:47 AM

My backup battery for my G3X will make a faint whine when it is switched on. It?s not enough to be annoying, but it?s enough to notice when the engine goes quiet. I kinda like it because it reminds me to shut it off after shutting down.

Another thought is to check the exhaust stack and see if it?s sagging enough to hit the lower cowling.

Just a couple of more potential spot to look.

RV Jerry · #15 11-09-2018, 11:06 AM

If you have a tipper canopy very good possibility the forwrward lip of canopy not sealing

Brantel · #16 11-09-2018, 12:25 PM

Quote:

Originally Posted by RV Jerry

If you have a tipper canopy very good possibility the forwrward lip of canopy not sealing

Prime suspect. I have found that my seal is kinda miffed up causing it to push up on the lip of the skin a little.

Phaser24 · #17 11-13-2018, 07:43 PM

I had the same type of noise (RV 7A with sliding canopy). Found one area where the weather seal had worn right over the pilot's head where the canopy meets the windscreen; fixed with new weather stripping.

Mark33 · #18 11-13-2018, 09:38 PM

Quote:

Originally Posted by rocketbob

Crank seal will sometimes whine as it starts to go bad. Noise will change with RPM. More like a faint squeal.

I?ve heard that exact sound myself.

6 Gun · #19 11-14-2018, 06:57 AM

I chased a whine for months thought it had to be altenator changed it out twice and still there went to HF and bought a scope like Dr uses and by accident the tip crossed intake gasket at cylinder and found a pin hole making all the noise new gasket no noise.
Bob

Brantel · #20 12-01-2018, 08:52 PM

So the mystery remains....

I have done some testing:

1. Put some tape over the front of the tipup canopy to cover the seam between it and the front top skin and flew the airplane to see if that is where the noise is coming from. Nope....its still there.

2. Did some RPM test to see if the noise volume or frequency changes with engine RPM. Nope....the engine RPM does not affect the noise.

3. Performed some airspeed test to see if the noise volume or frequency changes with airspeed. Yes.....the volume of the noise changes with airspeed. Lower volume at lower airspeeds and louder at higher all the way up to redline. The frequency seems very consistent.