Anything out there to dampen vibration for the pilots feet?

[moespeeds]

When I got my 8, the original builder had some nice interior panels and insulation on the inside of the firewall.

Since I prefer a more spartan interior, I pulled everything out. I get alot more noise, which I'm fine with. One thing I do notice is that when I set my feet flat on the floor, a high freq vibration goes all the way up to my eyeballs. It's not excessive, and I've had the prop balanced to a very low threshold, but it's annoying.

I wear very thin driving shoes when I fly because I have big feet, and that makes it even worse.

Has anyone done anything down on the floor where you rest your feet?

I was wondering if I could put down 2 strips of dynamat, then glue aluminum on top of that? Anyone else done something like this?

 

[riobison]

Thats a good question. I never really noticed it in my RV4 but probably due to my feet cooking.

But I do notice it on my 9A and it is annoying for sure. But my feet aren't cooking.

Tim

 

[tracy]

Stacks

Put some down turned exhaust stacks on end of exhaust. This made a big difference.

 

[Carl Froehlich]

Options depend on the source of the vibration. You have already balanced the prop. Now take a look at the exhaust pipe terminations. Do they have a clear downward bend or are they more straight? You can get some curved auto exhaust pipe tail pieces and experiment - at little cost. Exhaust drumming is a common issue.

Be careful with foam/rubber insulation. Most burn as well as off gas if warm. Years ago and RV-10 builder put in this stuff under the cabin floors. The off gas issue quickly resulted in the owner ripping it all out.

Carl

 

[DanH]

A cell phone app can identify the frequency, a good clue as to the source.

The aft-most rivet location in F-836 ribs tends to develop skin cracks, which tells there is a vibration problem there. The end of the tapered rib is unsupported. I drilled a few 1/4" holes in the floor (red) and injected a small blob of FB2000 at each location. May not cure a floor vibe, but it sure can't hurt.

A one piece SS exhaust ramp has worked out well. Note integral side panels.

And, a little pipe downturn is a good idea.

I have a little bit of floor vibe, but it's in one spot, aft of where my feet usually rest.
.

 

[RV8JD]

FWIW. I didn't have any belly skin cracks but wanted to reduce the floor vibration. Vetterman sells turndown extensions and straight extensions. I already had the turndown exhaust, but they were short. So Clint at Vetterman's sent me two short, straight extensions. They are each attached by one bolt. Hint: Put the bolt in per the instructions so the bolt is pointed toward the center of the airplane and not visible to a bystander standing next to the airplane (not like I did).

And the instructions:

 

[bjdecker]

FWIW. I didn't have any belly skin cracks but wanted to reduce the floor vibration. Vetterman sells turndown extensions and straight extensions. I already had the turndown exhaust, but they were short. So Clint at Vetterman's sent me two short, straight extensions. They are each attached by one bolt. Hint: Put the bolt in per the instructions so the bolt is pointed toward the center of the airplane and not visible to a bystander standing next to the airplane (not like I did).

And the instructions:

OT - Carl, do you have some screen material inside the fuel vents? 0000 SS wool, or similar.

 

[Wing nut]

Mine vibrated such that even the WIB, (wife in back), was asking me what that noise was. There weren’t cracks yet but I’m pretty sure it wouldn’t be long before there was. I did the Vetterman angled turned downs which maybe helped some but didn’t solve it. Unable to come up with a better idea I fashioned an insert which nested in the tunnel from the firewall rearward with 90 degree tapered flanges that riveted to the sides of the tunnel. I can’t remember the thickness for sure but it was something like .032 or .040 2024 aluminum. I pro sealed the front. In the end I was satisfied with the result. I may have an engine prop combination that evidently lends itself to vibration but this seems an under designed area of the airframe.

 

[RV8JD]

OT - Carl, do you have some screen material inside the fuel vents? 0000 SS wool, or similar.

No. I've been meaning to put a screen over them, but haven't for 1350 hours. Luckily we don't have many mud daubers up here. I need to do it though.

I do run a pipe cleaner or the end of a zip tie through them fairly often though to make sure they're unobstructed (I do know that mud daubers can block it in a very short period of time).