M18 Exhaust - Louder than a J3 Cub?

[Kevin Harberg]

Somewhat curious about frequent comments received from other pilots questioning if my Mite has "straight pipes". This Continental A65-F powered Mite has a stock M18 exhaust system with no apparent cracks or holes. I have recently replaced the cylinder exhaust stacks c/w gaskets thinking there may have been a leak contributing to "the noise" (no evidence of carbon trace). Hoping others familiar with Continental powered Mites may shed light on this. Attached is a photo of the engine compartment showing what I believe to be an original set of "pipes". Here is a YouTube link to a video of a low pass and the sound my Mite makes. Is it unusual, or comparitive to other CA65 powered Mites?

 

 

 

[Shadrach]

Hard to tell. But it seem pretty loud for a little A65.  Most low passes are loud. What’s more telling is if it’s loud at 1000ft.
Nice looking Mite!

[Hank]

That's a beautiful Mite, and positively silent compared to the Nieuport 28 whose video was suggested after watching yours. 

Apparently low passes have traditionally been done at full throttle since at least the days of WWI, making them quite loud. Bet your Mite is much quieter if you film a landing. 

[Kevin Harberg]

This flight was at 2150 RPM (75% for the CA65) initially at about 125mph and less on the return pass to keep at or below 109mph (IAS) for a wave to comply with the placarded open canopy max speed. I flew about 600ft off to the side of my friends acreage house on the initial pass and wasn't aware that he was on the other side of the treeline mowing his grass. Apparently he had seen my approach from a distance and started filming. After posting this topic, I was directed to a video of a Champ (doing aerobatics) and heard a very similar sound. I remember my father talking about Airknockers (Aeroncas), and the sound is identical. You can almost hear each piston fire at the low cruise rpm unimpared by prop noise produced by higher rpm or constant speed prop aircraft. Coincidentally, one of the comments regarding my mite's loud noise came from a J3 Cub owner. I guess we don't realize what they sound like when we are inside the cockpit while flying. I have not seen another mite in the air, so I had no idea what they sounded like until I received a copy of his short video.

Edited October 22, 2022 by Kevin Harberg
Spelling error

[A64Pilot]

Yes it’s louder than a Cub, a real Piper Cub is about the quietest aircraft there is, but sounds normal to me for a -65. 

Modern Cubs, like legend Cubs are much louder.

My C-140 with a C-85 has straight pipes and I think sounds about the same, I think as I’ve not heard it from the outside for years.

[Kevin Harberg]

57 minutes ago, A64Pilot said:

Yes it’s louder than a Cub, a real Piper Cub is about the quietest aircraft there is, but sounds normal to me for a -65. 

Modern Cubs, like legend Cubs are much louder.

My C-140 with a C-85 has straight pipes and I think sounds about the same, I think as I’ve not heard it from the outside for years.

Thanks for your reply. I had been told that my "pipes" were considered high performance long ago, in that they were equal length and therefore produced more horsepower for takeoff (full throttle high RPM). I will look more closely at them next time I remove the cowl. Your mention of straight pipes on your C-85 makes me think that possibly all I have is a heat muff for cabin heat. I don't know if the "Fancy bends" that produce equal length would still qualify as straight pipes, but I always thought that just meant no muffler. It is noisy enough in the cockpit to use hearing protection (I use a noise cancelling headset), but I thought it had to do with the pipes exiting just ahead of my right knee and only a couple of inches outside of it.