VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #1  
Old 08-08-2011, 11:09 AM
db8's Avatar
db8 db8 is offline
 
Join Date: Aug 2005
Location: Jeffersonville, IN
Posts: 463
Default Tip: RV-8 Canopy Seal

Following is a more detailed write-up on the canopy seal mod. for the RV-8. Feel free to add any comments or ideas to make it better or more applicable to other RVs besides the 8 or 4.

Since the 8 (and other RVs) have had issues with the cold air on the back of the neck, I came up with a canopy seal that is a real option because of the expanding and contracting of the fiberglass and aluminum to cover the gap year round (in an inexpensive way).

It basically is a mini shock bike pump that racers use that has a quick blow CO2 cartridge connection (that I did not use). The pump is manufactured by Bontrager, and is called the Air Rush Road Pump (retails for $34.99 http://bontrager.com/model/07331 was purchased from a local bike store). I located it on the left side of the canopy, and it has a twist knob on the end that holds air if tightened, and releases it if I twist it counter clockwise. That is the key because it allows the inner tube to hold the air while in flight. I cut a small inner tube valve (from an old tire at the bike store) and permanently screwed it into the adapter on the pump. The valve on an 18mm tube fits perfect.



I then connected a small vacuum tube that I picked up at an auto parts store to this valve stem. I put some sealant around the threads of the valve stem and just ?screwed? the vacuum tube over the stem and it formed an airtight seal. I then ran the tube through the existing bottom canopy support out the back to an 18mm bike inner tube (smallest I could find). I did have to drill a small hole (the diameter of the vacuum tube) toward the rear of the canopy support to allow for the vacuum tube to exit and connect to the inner tube valve.

I picked up some soft stretchable fabric (like thin spandex) from Hancock Fabrics (soft and wouldn't scratch the paint). I begged my wife to sew the soft velcro to this "housing" so the inner tube would free float inside the fabric tube. This allows the inner tube to expand and contract when pumping it with no issues. Then I attached the other velcro to the inside of the skirt so it would hold this stretchable housing with the tube inside it. The Velcro had a sticky side to it and was attached to the inside of the fiberglass canopy skirt.

The length of the inner tube is whatever you want to make it. The valve of the inner tube had to be placed about a foot from the canopy frame exit. The reason for this is because there was too tight of a clearance between the turtle deck and canopy if it were mounted any more forward. I used a tie wrap on a sticky tie wrap holder to secure the valvestem/vacuum tube assembly. I cut the ends of the inner tube to the desired length and used clamps to temporarily hold the folded over ends while the innertube cement cured and formed nonleaking ends.



My canopy without the seal is pretty tight, but I had my youngest shine a flashlight and blow compressed air from the outside when I was feeling/looking around from the inside, and it appears to work great. He never felt any drafts when he was my first passenger. The real results will be best proven in the winter, but it should work fine. Six short pumps before takeoff just after I close the canopy, and that's it. When I land, I turn the small knob counterclockwise to release the pressure. If I forget to do this, it still opens and is no problem.

Dave
__________________
Dave Buntin
http://i55.tinypic.com/iny6qa.jpg RV-8, N 130YS, BOYS & TOYS
[size="1"][color="Blue"]
Reply With Quote
  #2  
Old 08-09-2011, 06:44 AM
JAT JAT is offline
 
Join Date: Feb 2007
Location: Durango, CO
Posts: 126
Default

Dave,

Thanks for taking the time to explain your mod. I tried a "V" shaped rubber seal, but it only worked down to 20 degrees, so your mod is next on my list. My backseater thanks you as well!

Jim
Reply With Quote
  #3  
Old 08-09-2011, 09:13 AM
medic311 medic311 is offline
 
Join Date: Jul 2005
Posts: 57
Default nice write up dave

nice write up dave..on another note, who threw the paint? wow
Reply With Quote
  #4  
Old 08-09-2011, 01:50 PM
tkatc's Avatar
tkatc tkatc is offline
 
Join Date: Nov 2007
Location: NJ
Posts: 1,747
Default

When i first read about this mod (without pictures) I was skeptical...but man is that thing SWEET!! Very deserving award! Congrats!
__________________
My ATC opinion is NOT an official FAA recognized opinion, so any advice you get from me is ONLY my opinion.

Track my RV7A!!

Bought my flying -7A
Building an -8! (Fuse)
Reply With Quote
  #5  
Old 08-09-2011, 02:49 PM
rv8ch's Avatar
rv8ch rv8ch is offline
 
Join Date: Feb 2005
Location: LSGY
Posts: 3,133
Default beautiful RV8

Dave, thanks for taking the time to show me your beautiful RV8 at OSH, and thanks for having the cowl off so I could see the firewall.

Anyone who missed seeing Dave's RV8 really missed something special.

Congratulations on such a nice build, and thanks for taking the time to document the canopy seal trick!

Mickey
__________________
Mickey Coggins
http://rv8.ch
"Hello, world!"
Reply With Quote
  #6  
Old 08-09-2011, 04:39 PM
SteinAir SteinAir is offline
 
Join Date: Feb 2005
Location: Minneapolis
Posts: 2,471
Default

Very nicely done. I've looked at quite a few inflatable canopy seals that people have come up with over the years, but most I've seen in RV's and other planes have been either a plain rubber tube or the very expensive commercial airline grade tubing fed by any number of different air supplies. You definately have an elegant solution!

Cheers,
Stein
Reply With Quote
  #7  
Old 08-09-2011, 05:57 PM
gnuse's Avatar
gnuse gnuse is offline
 
Join Date: Jan 2005
Location: Georgia / 0GE5 / KSSI
Posts: 398
Default

It looks like a nice solution if it solves the problem of cold air being forced into the cockpit......especially the in the back area.
__________________
George

"God does not deduct from one's time on earth that which is spent in the air."
Reply With Quote
  #8  
Old 08-09-2011, 08:07 PM
panhandler1956's Avatar
panhandler1956 panhandler1956 is offline
 
Join Date: Jun 2006
Location: Ohio
Posts: 1,686
Default That is innovative!

Nicely done, both the mod and the write-up! Thanks for sharing! I see a retro fit in my birds future!
__________________
Brent Owens
EAA Chapter 9 Tech Counselor/Flight Advisor
Columbus, OH
RV-8 'Contrary Mary' flying
N784DE S/N #82614

www.fixedwingbuddha.com
Follow me on Facebook
Reply With Quote
  #9  
Old 08-09-2011, 11:38 PM
RViter RViter is offline
 
Join Date: Jun 2009
Location: Mesa, AZ
Posts: 242
Default Just a little slow on the uptake here ...

so don't take this the wrong way, it's my own ignorance showing.

A closed potato chip bag at sea level expands as the altitude/elevation increases, so why is a pump needed to inflate the seal? I am guessing that the volume of air in a sealed 'tube' would be too small to do the job of sealing tight, but what about a reservoir/canister?

Or, is the necessity the ability to control deflation, for example, landing at a high altitude field?

It's an elegant solution, and well executed, just wondering for my enlightenment. (And hoping enlightenment occurs as I get my RV-6A airborne, someday in the not too distance future.) THANKS
__________________
gary
RV-6A QB Tip-Up, 1st Flight 3/18/17
O-360-J2A (modified & F/I), Sensenich FP (cruise)
VP-X Sport, Dynon SkyView, VFR day
(FFZ) Mesa, AZ - N234GB -
www.mykitlog.com/garyc
Reply With Quote
  #10  
Old 08-09-2011, 11:51 PM
Casey Stewart's Avatar
Casey Stewart Casey Stewart is offline
 
Join Date: Apr 2010
Location: Arlington, WA
Posts: 174
Default

Quote:
Originally Posted by RViter View Post
so don't take this the wrong way, it's my own ignorance showing.

A closed potato chip bag at sea level expands as the altitude/elevation increases, so why is a pump needed to inflate the seal? I am guessing that the volume of air in a sealed 'tube' would be too small to do the job of sealing tight, but what about a reservoir/canister?

Or, is the necessity the ability to control deflation, for example, landing at a high altitude field?

It's an elegant solution, and well executed, just wondering for my enlightenment. (And hoping enlightenment occurs as I get my RV-6A airborne, someday in the not too distance future.) THANKS
That would work if you climb to altitude on every flight. You have to consider the take off and landing too. It wouldnt provide a very good seal then. Also a local flight or patern work wouldnt allow it to work.

Beautiful plane by the way. I did my best to contribute to your grass shadow at OSH
__________________
Casey D. Stewart
RV-7 N957RV (right seat if I am lucky)
C-150 N4265C for the PPL
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 02:16 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.