Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Cockpit Noise

Matronics Email Lists Forum Index -> Kolb-List

View previous topic :: View next topic

Author Message

NeilsenRM(at)comcast.net
Guest

Posted: Sat Nov 11, 2006 7:38 am Post subject: Cockpit Noise

Just food for thought...  Are you sure that all that noise is exhaust noise. 

My direct drive VW made enough noise to wake the dead so I added a muffler 

and a nice four into one exhaust system where I had four separate unmuffled 

pipes. It made no difference. When I switched to a redrive the noise got 

MUCH better. Then I got wondering about the muffler so I pulled it off. The 

noise stayed the same and the power went up. My conclusion was that the 

noise was prop noise.



When I reworked my motor mount to lower the engine the noise came back big 

time! Now I think the noise is from vibrations that aren't being dampened as 

well by the new mount. The new mount uses Lycoming bushings as vibration 

dampeners and they don't work as well as the Lord dampeners that Kolb 

supplied. I'm tuning the bushings and looking for softer ones.



So from my experience I would suggest you look at reducing vibrations being 

transferred to the airframe and look into sound deadening. David Key has a 

suggestion and a product that might help both of us. Dave would you share 

your photos with all of us?



Rick Neilsen

Redrive VW powered MKIIIc



---

- The Matronics Kolb-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Kolb-List

dhkey(at)msn.com
Guest

Posted: Sat Nov 11, 2006 1:48 pm Post subject: Cockpit Noise

First the sound proff(SP) stuff is heavy-thick rubber like.



I bought the stuff and folded it over once, put in in my sling seat taped it 

over my head. Took off and flew for 10 minutes, then reached back and pulled 

the stuff off and there was a big diffrence!!



I put it on the back and put it on my lexan thing.



I'm sure the prop noise was a major factor, so I covered the gap in the back 

it was open before. That hole in the back was acting like a giant megaphone 

through the cockpit. I was most impressed most by the pieces hung off the 

lexan. It works great. It puts the SP right behind my head and goes down to 

my mid sholders. It folds against the sides and really works well. I have to 

pieces of SP stuck together and the lexan is in the middle. I can really 

notice the diffrence and I think the tower can too.



I won't win best looking plane at the next flyin but I'll be able to hear 

who does.

(EMail me for pics.)



I got it on Ebay searh for "Dynamat Xtreme Extreme BULK"

I got one 32"x18" Sheet 4 SQ FT, one sheet is all you need.



It costs me $14 plus shipping, all you need is one sheet.

- The Matronics Kolb-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Kolb-List

David Lucas

Joined: 10 Jan 2006
Posts: 79
Location: Europe. based Amsterdam NL

Posted: Wed Nov 15, 2006 1:36 pm Post subject: Re: Cockpit Noise

 	  Quote: 	
		  That hole in the back was acting like a giant megaphone 	




Just wondering, Does the Tube back to the tail feathers also act like a drum with each passing of the nearby prop tip thus passing the noise back up the tube to the cockpit cage ?



Has anyone done any work on this theory by having some sound deadening material inside the tube at that point at least ?



Resonation can travel well within the confines of a tube especially if harmonics are involved. 



Just curious.         David

- The Matronics Kolb-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Kolb-List

Richard Pike

Joined: 09 Jan 2006
Posts: 1671
Location: Blountville, Tennessee

Posted: Wed Nov 15, 2006 1:53 pm Post subject: Cockpit Noise

I cut out a thick plug of foam rubber and stuffed it into the tube just 

behind my right elbow to keep cold air from flowing out of it. Don't know if 

it is quieter, but my elbow has quit turning blue...



Richard Pike

MKIII N420P (420ldPoops)

do not archive

---

- The Matronics Kolb-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Kolb-List

_________________
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0

Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing.

NeilsenRM(at)comcast.net
Guest

Posted: Wed Nov 15, 2006 2:54 pm Post subject: Cockpit Noise

David



I have been trying to make my MKIII quieter since I lowered my engine by 

adding sound deadening material everywhere I could think of with no luck. I 

never considered the fuselage tube but that could be it. definitely worth 

checking. My tube is plugged near the tail feathers but not on the fuselage 

end so it might be even more noisy.



Good idea.



Rick Neilsen

Redrive VW powered MKIIIc



---

- The Matronics Kolb-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Kolb-List

APilot(at)webtv.net
Guest

Posted: Wed Nov 15, 2006 3:23 pm Post subject: Cockpit Noise

You make a good point of air coming forward in the Mk III tube.  I have

been wondering about cutting a louver in the under side of the nose cone

to relieve the vacuum which would also stop the forward movement of air

in the tube.  According to Mr. Newton, the reaction would be less from

the forward moving air.  However, the drag of a louver would be more.

Hard to figure.

 Vic

- The Matronics Kolb-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?Kolb-List

Display posts from previous:

	Matronics Email Lists Forum Index -> Kolb-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum