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Old 07-08-2019, 06:23 PM
UnPossible's Avatar
UnPossible UnPossible is offline
Join Date: Jan 2008
Location: Granbury, TX
Posts: 524
Default Screws vs quarter turn fasteners around the firewall

Hey -

I am making good progress on my 10, and am looking ahead to working on the cowling. I am not a big fan of Van's hinges around the firewall, and on my 7A I used quarter turn fasteners all the way around the firewall. However on my 10, I am considering just using screws and nut plates. Why????

1) Price... I think the firewall kit fastener kit is around $500.... screws and nut plates would likely be $25 or less.

2) Putting the cowling on and off is a bit of a pain. The quarter turn fasteners hang down from the cowling and can scratch the paint if you aren't really careful getting everything aligned before setting the cowling down into position.

3) Long term maintenance... I have had to replace a couple of the quarter turn fasteners (which were replaced under warranty) when they failed to lock into place. Additionally, I have a couple of them that don't want to stay in the cowling when unlocked.

4) Speed... while the quarter turn fasteners are going to be faster... using a screw gun I can't imagine the time difference being all that much.

Is there some reason I am not thinking of why I shouldn't go ahead with screws and nut plates?

Jason Tremble
RV-7A (Flying and Sold)
RV-10 in process (@#$$%# Cabin Top & Doors)
Paid for 2020
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Old 07-08-2019, 06:50 PM
rockwoodrv9 rockwoodrv9 is online now
Join Date: Dec 2011
Location: Meridian ID, Aspen CO
Posts: 2,575

I used the 1/4 turn fasteners. I would use screws if I built again for all the reasons you mentioned.
Williamston MI
O-320 D2A
Awaiting DAR Inspection
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Old 07-08-2019, 06:52 PM
rocketman1988 rocketman1988 is offline
Join Date: Jun 2010
Location: Sunman, IN
Posts: 1,978
Default Skybolts

I did the whole cowl with skybolts, and never looked back...
Aerospace Engineer '88

Structure - 90% Done
Cabin Top - Aaarrghhh...
EFII System 32 - Done
297 HP Barrett Hung
ShowPlanes Cowl with Skybolts Fitted - Beautiful

Dues+ Paid 2019,...Thanks DR+
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Old 07-08-2019, 06:58 PM
rvbuilder2002 rvbuilder2002 is offline
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 8,601

Some people complain about the longevity of the standard hinges.
Keep in mind that the threads on screws are like saw teeth to fiberglass.
With vibration, plain screws can make a mess of a cowl over time.
If you do decide to go with screws you should use ones that have some smooth shank (like AN509 or AN525).
Using a flush screw with a tinnerman washer can be beneficial because of the increased baring area provided by the countersink.
The main down side in my opinion, even if you do these things to mitigate the screws causing wear in the hole, is that with the custom paint jobs done now a days, it is common for the paint or clear coat to migrate out from under the screws over time.
Any opinions expressed in this message are my own and not necessarily those of my employer.

Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
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Old 07-08-2019, 07:07 PM
mtnclimber mtnclimber is offline
Join Date: Apr 2010
Location: Nathrop Colorado
Posts: 68

I used -8 screws on my 8, and after 3 years they look like the day I put them in. I've won a few bets; I can remove or install the upper or lower cowls in less than 2 minutes each.

I also removed the hinge pins on my 9A, and replaced with -8 screws. I use the Bosch gyroscopic screwdriver from Home Depot. 'Wont leave home without it'

Roger Bloomfield
KAEJ Buena Vista 8,000 MSL
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Old 07-08-2019, 07:15 PM
Kyle Boatright Kyle Boatright is online now
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 3,965

I used screws across the top and bottom of the cowl on my -6. I reinforced both flanges on the cowl with extra layers of fiberglass. That system has been faultless for ~18 years.

I went with quarter turns on the -10 and wish I hadn't. They are expensive, harder to install, and there are probably other issues I don't know of right now.
Kyle Boatright
Atlanta, GA
2001 RV-6 N46KB
2019(?) RV-10
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Old 07-08-2019, 07:48 PM
Charles in SC Charles in SC is offline
Join Date: Aug 2006
Posts: 695

I remember some Mooneys that had screws holding the cowling on. That was before screw guns.
RV 7
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Old 07-08-2019, 07:52 PM
rocketbob's Avatar
rocketbob rocketbob is offline
Join Date: Jun 2006
Location: 8I3
Posts: 3,424

Originally Posted by rockwoodrv9 View Post
I used the 1/4 turn fasteners. I would use screws if I built again for all the reasons you mentioned.
I agree. I would just go with screws and nutplates if I were doing my rocket cowling over. Camlocs are nice, don't get me wrong but its not that much more work to use a cordless drill.

Please don't PM me! Email only!

Bob Japundza CFI A&PIA
N673AC RV-7 borrowed horse
N678X F1 Rocket, under const.
N244BJ RV-6 "victim of SNF tornado" 1200+ hrs, rebuilding
N8155F C150 flying
N7925P PA-24-250 Comanche, restoring
Not a thing I own is stock.
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Old 07-08-2019, 08:18 PM
Walt's Avatar
Walt Walt is offline
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 5,389

Hinge pins here for the last 15 years, work like a dream, super easy to remove/install cowls. I used screws on the bottom of the cowl and on the front only. Would do the same again if I was to build another.
Oh yea forgot the most important part... they look good!
Walt Aronow, DFW, TX (52F)

EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs, New Titan IO-370, Bendix Mags
Website:, Email:, Cell: 972-746-5154
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Old 07-08-2019, 08:25 PM
Rallylancer122 Rallylancer122 is offline
Join Date: Aug 2013
Location: Oconto, WI
Posts: 125

My Cessna has screws. There has to be a pretty good reason to take that cowling off.

My Dad's RV has skybolts. I will pop that thing off for hardly any reason at all.

I would do the quarter turns, if for no other reason it takes away one more excuse to have a looksee under the hood. In the grand scheme of things it's probably not much more time, but psychologically those screws are a pain in the behind.

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