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Converting Piano Hinge Cowl to Fastener?

dmat

Well Known Member
Advertiser
Hi,

Has anyone done this? Did a search and couldn't find anything.

Thanks,
D
 
I did

I replaced my top piano hinge only on my RV4. Came out like hammered dog poop. My plane is painted, thought I could do it without screwing up the paint HAHA. The gap between the metal and cowl is huge, just couldn't get it right.
It REALLY wasn't worth the hassle. When done from the start its a different story. If I was building a new rv, I'd stick with piano hinge all around, yes they do break, but just is easier for me. I would try using or looking into the extruded hinge I think the number is MS20001P. Good luck!
 
Skybolt

Hi

I put Skybolt fasteners in my cowl top where it meets the firewall. Done properly it looks great. I kept the hinges to joint top to bottom and the bottom cowl to the firewall. They work well there.
 
yes

I have converted 2 RV-6's from standard Van cowls with piano hinges to James Cowls with ALL Mil-Spec 1/4 turn fastners. I like it.
 
Retro-Fitting Hinge to Skybolt Fasteners

I replaced my top piano hinge only on my RV4. Came out like hammered dog poop. My plane is painted, thought I could do it without screwing up the paint HAHA. The gap between the metal and cowl is huge, just couldn't get it right.
It REALLY wasn't worth the hassle. When done from the start its a different story. If I was building a new rv, I'd stick with piano hinge all around, yes they do break, but just is easier for me. I would try using or looking into the extruded hinge I think the number is MS20001P. Good luck!

Hammered dog poop is not a good thing. Skybolt supports many RV owners that convert from hinge to the fasteners and I would like some input on what we can do better. I have read about challenges to match the interlocking flange holes to the cowling. For a cowling that has not been painted, you can see through the material and determine a centering hole. This all assumes you are using a Skybolt kit with the template inserts. Winging it without these inserts is a recipe for issues. For a painted cowling, no can do. I have tried hole centering tools, but with the butt fit, those just leave much to be desired. My question to the masses is, would a transfer fitting that installs in the flanges work? We can make hole transfer fittings but you need one for each hole in the upper cowling in order to match the hose with precision. I don't think doing one at a time will work well at all.

I look forward to feedback,

Ned Bowers, Skybolt - Oshkosh July 24 thru 26th
 
Hammered dog poop is not a good thing. Skybolt supports many RV owners that convert from hinge to the fasteners and I would like some input on what we can do better. I have read about challenges to match the interlocking flange holes to the cowling. For a cowling that has not been painted, you can see through the material and determine a centering hole. This all assumes you are using a Skybolt kit with the template inserts. Winging it without these inserts is a recipe for issues. For a painted cowling, no can do. I have tried hole centering tools, but with the butt fit, those just leave much to be desired. My question to the masses is, would a transfer fitting that installs in the flanges work? We can make hole transfer fittings but you need one for each hole in the upper cowling in order to match the hose with precision. I don't think doing one at a time will work well at all.

I look forward to feedback,

Ned Bowers, Skybolt - Oshkosh July 24 thru 26th
Ned, Glad to see you would like to help. I did not use your hardware as stated above but the process is identical. I did install new cowls so I could see through the fiberglass. My thoughts: the centering of the holes is very important and any centering devise that lifts the cowl to make a mark will change the radius of the curve on the top cowling, thus moves the holes.
What I did actually was fabricate a strip of aluminum with the tabs shaped and properly spaced, then inserted the strip into the airframe. This has been done many times by many builders. The key is to NOT drill the holes in either the fiberglass or the tab until one has final alignment. Then a well placed small hole will make the center of the larger hole. In the case of the Skybolt tabs, if you could sell undrilled versions, so builders could drill their own holes instead of trying to finding the existing holes under a painted cowl might help. Just my .02....
 
It appears the airplane is new to you. Properly done, piano hinges work great. I will assume the builder on yours didn't do it right and you want to change as a result of it not working well on your airplane. If that is the case,
describe your issues. Things like hinge alignment, difficult removal, etc... can and have been fixed. Sometimes the fix is pretty easy, sometimes impossible.

If I was going to change, short of a new cowling, I would remove the hinge eyes and not mess with trying to remove the entire hinge. You could then fabricate the tabs. It will take some careful thought and probably some shimming. The hinge isn't very wide.
 
In the case of the Skybolt tabs, if you could sell undrilled versions, so builders could drill their own holes instead of trying to finding the existing holes under a painted cowl might help.

Having done this modification a few times as well this is a great recommendation by Bob.
undrilled versions would be huge help.
 
Skybolts

I just finished installing Skybolt 1/4 turn fasteners on my '93 RV6A that I have owned for 2 years.
Shortly after getting the plane home, I decided on a GRT panel with the existing vacuum system for back up and a back up battery for the efis. After finishing the panel, I discovered it was almost impossible to get the piano hinge pins installed across the top of the firewall. I had mounted the oil and fuel press senders in the spot my hand used to fit in while installing them. I was thinking about Skybolt anyhow so that made up my mind.
I removed the top of firewall and side horizontal piano hinges and kept the firewall side hinges.
This allowed me to install the cowlings back in their exact locations using the side vertical hinges and clamping the front exactly even together.
I then was able to accurately mark the holes to drill to mount the studs, then paint the cowling.

The worst problem I had was the original builder recorded the paint name and color number so I could match it, BUT.....The color gray he recorded as the exterior gray was actually the interior gray so now I have a light gray stripe on the cowling matched to a medium gray stripe down the fuselage.

Hopefully I will get the right gray this week.

Love the Skybolts.
 
Skybolt Vans RV Hole Finder

Skybolt introduces yet another innovation to make installing fasteners easier and more efficient ?

SK-RVC114 (14 sets) and SK-RVC119 (19 sets) Hole Finders.

As we begin to see more and more conversions from hinge to fasteners, including builders removing previously installed hinge and installing the Skybolt fastening system, hole finding becomes a challenge. Typically, on the initial build, we have relied on the cowling skins being transparent (to some extent) in order to drill the initial pilot holes at center. With the new push to retrofit existing aircraft, we can no longer rely on transparency because of paint. By modifying our current Cleko inserts to be used with the Skybolt SK-RVFS1 Interlocking Flanges to accept a magnet, we can locate the center hole quite accurately in all cowling skins with a small dowel pin. Our kits include a limited number of the inserts to satisfy the Cleko requirement. (This is the equivalent of a flange without the hole as stated in a previous post). The complete sets adding a magnet and dowel pin however, answer the issues with painted (opaque) cowling retrofits.

Per our installation instructions where we describe the SK-RVC1 Inserts as a method to Cleko the cowling to the flanges before the receptacles are installed, obviously for this to work, you have to drill a 1/8 inch hole in the cowling. Using the inserts in the same manner, tape the inserts with the magnet installed into the back of each flange. Set the upper or lower cowling into position with a ratchet strap, then drop the dowel pin in the general vicinity of each flange center hole. Drop it a few times to insure the pin centers at the exact same spot. Drill a 1/8 inch pilot hole. Insert a Cleko (the magnet will push away from the insert) and proceed to the next location.

SK-RVC114 Sets (14) are $33.46 (Fasteners not included) for RV4 and RV8
SK-RVC119 Sets (19) are $45.41 (Fasteners not included) for RV6 thru 10

Order On-Line at www.skybolt.com or call us, 800-223-1963.

I'll post some photos and a drawing soon.
See you at Oshkosh, Ned
 
Skybolt retrofits

In replacing my piano hinges, I was not going to (and did not) replace the side firewall hinges. I discovered that this allowed me to accurately place the cowlings in position to mark then drill the holes across the top of the firewall.

If I was to replace the side firewall hinges, I would do that last, after completing the top firewall Skybolts and the sides.
 
In replacing my piano hinges, I was not going to (and did not) replace the side firewall hinges. I discovered that this allowed me to accurately place the cowlings in position to mark then drill the holes across the top of the firewall.
Many people have pointed out before that really, the piano hinges can't be beat for the long straight joints (top-to-bottom joint, firewall joint). It's the curved ones where people have trouble, and that's where Skybolt and similar fasteners make the most sense.

Personally i'd use them on the bottom-cowl-to-bottom-of-firewall joint as well. The piano hinges on my -6 started shedding eyelets down there, so I replaced the broken section with a nutplate and a couple of screws at the end closest to the exhaust pipes. That's holding solid and the rest of the piano hinge hasn't shown any tendency to shed more eyelets.
 
I ditched my piano hinges and use nutplates and screws. It works well for me. In retrospect I should have taken more time to get my piano hinges to work better. I know others have good success with them. Still, I don't have any real reqrets going to screws.
 
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