[herve-RV7]

I'm just wondering which fastners to buy for the cowl on my 7A :
a) - Milspec or skybolt ? Any significant difference in the two products. Any difference in the N? of fastners supplied in the kits. Skybolt also supplies the side strips, which is the simple way for European builder. Not a big issue, but ...
b) - complete kit or just firewall. One the different builder sites, I understand that most are going the firewall only.
c) - Phillips or slotted.

Thnks in advance for feed back / comments

 

[carguy614]

I used Milspec

Used the Milspecs on my 9A. They are an awesome quality fastener. Used them only on the top cowl where the cowl meets the top skin. Used hinges to mount the lower cowl, and between upper and lower cowl. Reaching through the oil door to get the top cowl pins is a pain. Mine has the phillips head, and I pitched them 3.5 inches across the top, and a little closer for the three or four down each side. They work beautifully.
Highly recommended.
Regards...Chris

 

[flybill7]

Cowl Fasteners

Herve,

I went with MilSpec, phillips head, complete kit. MilSpec was very good to deal with. They improved the fastener heads and replaced the ones I had (not installed yet) free of charge. Installation was easy. Cowl goes on and off quickly. I don't have anything to compare them too but so far I have been pleased with them.

 

[Capflyer]

Stick with the Hinges

Just a thought......

Not sure why everyone spends so much time making a clean aircraft with flush rivets then spends big bucks for very visible fasteners on their cowling.

The hinges make it easy and quick to take the cowling on and off and the side hinges between the top and bottom cowling are easy to hide with a hidden hinge pin that goes in from the cockpit.

I can easily and quickly remove or install my cowling and my buddy with only firewall fasteners needs another set of hands and it takes 4x longer, dropped screw drivers, chipped paint, and dropped on the floor fasteners that can get lost.

In about the time it takes to install and remove all those fasteners only once you could have all your hinge eyes lines up and pins bent properly making easy work of getting the pins in and out.

 

[szicree]

Not sure why everyone spends so much time making a clean aircraft with flush rivets then spends big bucks for very visible fasteners on their cowling.

The fasteners are visible, but quite flush and attractive.

The hinges make it easy and quick to take the cowling on and off

The pin along the top of the firewall is accessed through the oil door, requiring arms like E.T.

firewall fasteners needs another set of hands and it takes 4x longer, dropped screw drivers, chipped paint, and dropped on the floor fasteners that can get lost.

I do it solo no problem, the fasteners are retained in the cowl, and if you can build a plane you can turn a screw 1/4 turn without dropping your tools.

For the sides and lower firewall I used the hinges, but horsing around with that curved hinge while scratching and burning my arm just wasn't fun.

 

[Capflyer]

The pin along the top of the firewall is accessed through the oil door, requiring arms like E.T.

Ok...full disclosure here...It is a little tougher when the engine is hot right after a flight and my forearems are slim so fit through the oil door nicely. I can see your point if one has heavy arms.

 

[CNEJR]

Used Skybot across the top firewall, hinges on the remainder. Skybolts work & look fine.

 

[mike newall]

The other problem with the hinge fasteners are that after a few hundred hours, they start to break ears off............. Now you have a dilemma - do you suffer in silence, or drill them all out, replace them, repaint etc etc.

 

[Captain Avgas]

Herve,

I went with MilSpec, phillips head, complete kit. MilSpec was very good to deal with. They improved the fastener heads and replaced the ones I had (not installed yet) free of charge. Installation was easy. Cowl goes on and off quickly. I don't have anything to compare them too but so far I have been pleased with them.

I had exactly the same experience. Milspec highly recommended....good product....good company.

 

[Rick6a]

Economical Alternative

A low cost alternative to pricey cowl attachment treatments that has worked very well for me is simply #8 SS screws and (floating type) nutplates through an 4 foot long .050 metal strap that I scalloped to save weight. I went this route because I changed out both cowls on my old C-150 using floating nutplates and never had to replace a single one in 18 years. Until several months ago, I always used high visibility SS Tinnerman washers under the screw heads on the RV cowl, empennage fairing, and wheel pants but started to ask myself if that was really necessary. For my purposes, I don't think it is.

 

[RV7ator]

I install 15 studs on the top cowl-to-firewall seam every 4" or so. Watch out for interference with the engine mount on the lowest ones. I use 4002 Camlocs from Spruce. They're cheaper than others, functionally equivalent, look the same. You can choose style, size, and quantity to suit you. I strongly recommend avoiding the flush mount receptacles that require chamfering the hole. That's a very difficult task yielding scalloped out holes, it's weaker than the "plus flush", and really doesn't look any better. Hinges everywhere else except along the bottom edge either side of the tailpipes; there it's screws into a nutplated strip of aluminum riveted to the firewall.

I've seen top hinge installations with a tiny access door in the top center aft edge of the top cowl that captures protruding 1/4" hinge wire ends. These you remove from the outside. Looks a lot more sensible than blindly groping inside the oil door, and it doesn't look any worse than the side hinge ends at the front that builders decorate with all sorts of do-dads.

John Siebold