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Matt Dralle
Site Admin
Joined: 08 Nov 2005
Posts: 26320
Location: Livermore CA USA
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 Posted: Sat Oct 30, 2010 5:14 pm Post subject: Canopy Skirt Buzz... |
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Hello Listers,
After the very first flight on the RV-8, I discovered that the fiberglass skirts around the canopy loved to buzz against the turtle deck skin at anything over about 100mph. To soften the intersection between the skirt and the skin I added a row of Velcro-brand "loops" tape all the way around the base of the canopy skirt on the inside including around the bottom of the windscreen so that when the canopy was closed any skin to skirt areas were cushioned with a thickness of the Velcro.
That worked great and totally eliminated the buzzing and also sealed up the cabin nicely. I was pleased.
But, after a Summer in California and 112 hours of flying, the Velcro just didn't hold up. In the Summer sun, the glue became gooey and the tape slipped out of position along the curve behind the passenger and looked like grandma's slip was showing. Along the extreme rear where the skirts come together and the fit is pretty tight, the glue squeezed out from the heat and kind of goo-ed all around on the metal.
So, I removed the skirts a couple of weekends ago and literally spend a whole weekend removing the Velcro and all of the glue. I was lucky and the in the process I didn't remove any of the textured paint on the skirts or windscreen frame - whew, that was a scary two days.
This weekend I finally got to take her out for a flight after the oil cooler replacement (all went fine, btw) and try out the new "tape-less" installation.
Holy COW!! It was SOOOOOO noisy! At 200mph I took the headphones off and couldn't believe the DB level. I really couldn't stand the noise level with the headphone ON, and without then it just plain hurt. I slowed down to about 150mph and the noise decreased slightly, but not that much. I slowed down to a stall and finally the buzzing stopped, but as soon as I pushed the nose over and speeded up a little it started again.
Obviously I'm going to have to put something like the Velco back on the inside of the canopy frame. But what? I'm guessing that all RV-8's must have this issue. I surprised there isn't something in the plans to deal with it. Is there some magic tape/insulator that people are using for this that will hold up in the heat of the Summer sun?
Thanks in advance!
-
Matt Dralle
RV-8 #82880 N998RV
http://www.mattsrv8.com - Matt's RV-8 Construction Blog
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 112+ Hours Total Time Since May 2 2010 Test Flight!
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Matt Dralle
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Bret Smith
Joined: 09 Jan 2006
Posts: 178
Location: Mineral Bluff, GA
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| Posted: Sat Oct 30, 2010 7:15 pm Post subject: Canopy Skirt Buzz... |
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Matt,
I bought some .75" wide UHMW tape from McMaster Carr. It is available in a
number of widths and thicknesses and applied it to the inside of the canopy
where it slides along the fuselage skins. It cuts down on the airflow and
does not scratch the paint. This is on an RV-9a slider so I'm not sure if
it would work for you in the -8.
Bret Smith
RV-9A N16BL
Blue Ridge, GA
www.FlightInnovations.com
--
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Bret Smith
RV-9A (Emp) |
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rveighta(at)comcast.net
Guest
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| Posted: Sun Oct 31, 2010 6:02 am Post subject: Canopy Skirt Buzz... |
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Matt, I had a similar problem with my 8A. Later, I built an 8 and was determined to not have a sealing/buzzing problem with it. Here's what I did -
I taped freezer paper to the turtle deck and fuselage sides, then made up a batch of micro about the consistency of dough so it wouldn't run, and
spread that over the inside bottom of the skirt. I then closed the canopy down as tightly as I could and let the micro set up over night. The next day,
after some scary moments, I was able to break the canopy free, and viola! I had a very nice, tight fit, and because the canopy skirt was thicker at
the bottom, the buzz went away.
You may not be able to follow this approach if you have already painted the plane, but it really worked great for me.
Walt Shipley
RV 8, 8A (Sold) RV12 under construction
P.S. I can probably dig up some photos if you want them
---
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bjudge(at)gmail.com
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| Posted: Sun Oct 31, 2010 9:02 am Post subject: Canopy Skirt Buzz... |
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Matt:
Getting that canopy skirt to seal up well is a tough one that I've struggle with for awhile, I guess my passengers have suffered along with me. I jammed epoxy with micro all the way around the perimeter to make a good seal and that worked for about the first 100 or so hours and then I got the same buzzing you've. My latest fix was to inject "great stuff" polyurethane foam around the perimeter and let it expand and fill the voids.
In both cases I just put plastic down on the aft fuse and masked off the exposed parts of the skirt. Epoxy and foam don't adhere to the plastic, almost any plastic works, cling wrap, hefty bags, drop cloth from home depot. Now my canopy closes and the aft skirt is very tight against the fuse and my passengers are very happy.
Bill Judge
N84WJ RV-8, 550 hrs
rv-8.blogspot.com
[quote]Time: 06:14:58 PM PST US
From: Matt Dralle <dralle(at)matronics.com (dralle(at)matronics.com)>
Subject: Canopy Skirt Buzz...
Hello Listers,
After the very first flight on the RV-8, I discovered that the fiberglass skirts
around the canopy loved to buzz against the turtle deck skin at anything over
about 100mph. To soften the intersection between the skirt and the skin I added
a row of Velcro-brand "loops" tape all the way around the base of the canopy
skirt on the inside including around the bottom of the windscreen so that
when the canopy was closed any skin to skirt areas were cushioned with a thickness
of the Velcro.
That worked great and totally eliminated the buzzing and also sealed up the cabin
nicely. I was pleased.
But, after a Summer in California and 112 hours of flying, the Velcro just didn't
hold up. In the Summer sun, the glue became gooey and the tape slipped out
of position along the curve behind the passenger and looked like grandma's slip
was showing. Along the extreme rear where the skirts come together and the
fit is pretty tight, the glue squeezed out from the heat and kind of goo-ed all
around on the metal.
So, I removed the skirts a couple of weekends ago and literally spend a whole weekend
removing the Velcro and all of the glue. I was lucky and the in the process
I didn't remove any of the textured paint on the skirts or windscreen frame
- whew, that was a scary two days.
This weekend I finally got to take her out for a flight after the oil cooler replacement
(all went fine, btw) and try out the new "tape-less" installation.
Holy COW!! It was SOOOOOO noisy! At 200mph I took the headphones off and couldn't
believe the DB level. I really couldn't stand the noise level with the headphone
ON, and without then it just plain hurt. I slowed down to about 150mph
and the noise decreased slightly, but not that much. I slowed down to a stall
and finally the buzzing stopped, but as soon as I pushed the nose over and
speeded up a little it started again.
Obviously I'm going to have to put something like the Velco back on the inside
of the canopy frame. But what? I'm guessing that all RV-8's must have this issue.
I surprised there isn't something in the plans to deal with it. Is there
some magic tape/insulator that people are using for this that will hold up
in the heat of the Summer sun?
Thanks in advance!
-
Matt Dralle
RV-8 #82880 N998RV
http://www.mattsrv8.com - Matt's RV-8 Construction Blog
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 112+ Hours Total Time Since May 2 2010 Test Flight!
________________________________ Message 2 _____________________________________
Time: 08:15:35 PM PST US
From: "Bret Smith" <smithhb(at)tds.net (smithhb(at)tds.net)>
Subject: RE: Canopy Skirt Buzz...
Matt,
I bought some .75" wide UHMW tape from McMaster Carr. It is available in a
number of widths and thicknesses and applied it to the inside of the canopy
where it slides along the fuselage skins. It cuts down on the airflow and
does not scratch the paint. This is on an RV-9a slider so I'm not sure if
it would work for you in the -8.
Bret Smith
RV-9A N16BL
Blue Ridge, GA
www.FlightInnovations.com
--
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Matt Dralle
Site Admin
Joined: 08 Nov 2005
Posts: 26320
Location: Livermore CA USA
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| Posted: Sun Oct 31, 2010 9:04 am Post subject: Canopy Skirt Buzz... |
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At 09:45 AM 10/31/2010 Sunday, you wrote:
| Quote: |
Matt,
I haven't had that problem.
Stan Sutterfield
I'm guessing that all RV-8's must have this issue.
|
Stan,
Wow, really? Do you have anything between the fiberglass skirt and the top of the turtledeck? Foam, velcro, etc?
Do you have a perfectly tight fit all the way around? I've got a little pooch on both sides kind of at the center of the concave, roundy part.
One thing I forgot to mention in my original post was that I tried unlatching the canopy to see what impact it would have. The buzz got even louder.
Another thing I tried was adjusting the Prop RPM. There was definately a relationship between the buzz and the RPM, not related to speed of the aircraft. A harmonic of sorts.
Another odd behavior was that when I was climbing out, I didn't hear it at all. It wasn't until I pushed the nose over and started picking up speed that it started.
Matt
-
Matt Dralle
RV-8 #82880 N998RV
http://www.mattsrv8.com - Matt's RV-8 Construction Log
http://www.youtube.com/MattsRV8 - Matt's RV-8 HDTV YouTube Channel
Status: 111+ Hours TTSN - The Fun Never Stops...
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Vanremog(at)aol.com
Guest
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| Posted: Sun Oct 31, 2010 9:51 am Post subject: Canopy Skirt Buzz... |
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Matt-
I encourage you to try the UHMW tape in this area. I've had it in there since day one as a seal and it still works and looks the same after 13 yrs.
-GV
In a message dated 10/30/2010 6:15:50 P.M. Pacific Daylight Time, dralle(at)matronics.com writes:
| Quote: | After the very first flight on the RV-8, I discovered that the fiberglass skirts around the canopy loved to buzz against the turtle deck skin at anything over about 100mph. To soften the intersection between the skirt and the skin I added a row of Velcro-brand "loops" tape all the way around the base of the canopy skirt on the inside including around the bottom of the windscreen so that when the canopy was closed any skin to skirt areas were cushioned with a thickness of the Velcro.
That worked great and totally eliminated the buzzing and also sealed up the cabin nicely. I was pleased.
But, after a Summer in California and 112 hours of flying, the Velcro just didn't hold up. In the Summer sun, the glue became gooey and the tape slipped out of position along the curve behind the passenger and looked like grandma's slip was showing. Along the extreme rear where the skirts come together and the fit is pretty tight, the glue squeezed out from the heat and kind of goo-ed all around on the metal.
So, I removed the skirts a couple of weekends ago and literally spend a whole weekend removing the Velcro and all of the glue. I was lucky and the in the process I didn't remove any of the textured paint on the skirts or windscreen frame - whew, that was a scary two days.
This weekend I finally got to take her out for a flight after the oil cooler replacement (all went fine, btw) and try out the new "tape-less" installation.
Holy COW!! It was SOOOOOO noisy! |
[quote][b]
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aerokinetic(at)sbcglobal.
Guest
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| Posted: Sun Oct 31, 2010 7:46 pm Post subject: Canopy Skirt Buzz... |
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Matt,
The goo from the Velcro should have wiped right off with mineral spirits... With zero effect to the paint.
Also good for removing oily stuff from the belly etc -beats 409 or isopropyl and anything water based.
Lots of folks are scared to use it on paint -because it's sold as 'paint thinner'. But it won't affect cured finishes *at all* -unlike acetone, MEK or laquer thinner -which is not the same.
Stoddard solvent is mineral spirits, FWIW
Scott
RV-4 #772
May or may not have been sent from my iPhone
On Oct 31, 2010, at 2:59 AM, RV-List Digest Server <rv-list(at)matronics.com>
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