cowl attachment

Does any one out there have some good advice on attaching the cowl of an rv-6? I'm looking at pics of different rv's with dzus or screw attachmet instead of the piano hinge affair. Is it an easier to maintain screw/dzus? does the piano hinge require maintenance/replacement over time?
Pat in Calgary

This is what you can do with skybolt camlok fasteners



They are very simple to install and make cowl removal a snap. Downside is that they are pricey, but when you balance out how easy they are to install etc, it eases the pain.

It is my understanding that some builders are having trouble with the piano hinge attachment method in that the eyes of the piano hinge have a tendancy to crack and break.

Regards,

There is another downside with the Skybolt fasteners

The downside is you have to deal with Skybolt.

If you go the Skybolt route, order your kit 6 months before you need it. They have a monopoly on the product and they know it. They should change thier motto to "We have fasteners so you can get screwed".

Just curious: Skybolt fasteners seem to be simply Dzus fasteners for the most part. So what makes Skybolt so different from the Dzus fasteners available through any automotive speed racing outlet?

Perhaps someone can offer the particulars?

For a typical reference: http://www.racerpartswholesale.com/dzus.htm

Here's an even better one that has stainless Dzus as well as various types of recepticles including anti-vibration type.
http://www.southco.com/landingpages/dzus/

Confirmation

The hinges work very well but there are some weaknesses. I have had one link break off in the upper aft hinge where it curves down. There is a lot of stress on the rivets holding the hinge half to the fiberglass at the bottom of the cowl. Mine were working badly in the fiberglass at around 100 hours when I replaced them with extended plates, platenuts, dimple washers and #8 screws (bottom only). In the AirVenture Cup race last year one of the RV-4's upper cowl caved it forcing a slow down to get to the finish situation. The pilot told me later that 4 hinge links on one side were broken. They do the job nicely and cleanly but you should expect some irregular maintenance with the system.

Bob Axsom

This is some advice I received from Pete James a while back:

I used Clocs on the Cowl to firewall, not Piano Hinge, so that I could quickly remove the cowls for daily inspections. By the time I finished the cowls and baffles they had paid for themselves, as I must have had the cowls on and off 50 times. Check http://www.skybolt.com/
WHETHER YOU PLAN TO USE CLOCS OR PIANO HINGES YOU SHOULD FIT THEM BEFORE YOU FIT THE ENGINE FRAME OR IT IS NEARLY IMPOSSIBLE TO COMPLETE THE FIREWALL RIVETING.

Ack. The forum won't let me put 6 images in one post. Here's the rest:

Vern, I'm all ears too... would love to hear why the alternative wouldn't work..

Milspec Kit?

I have a Sam James cowl and am planning on going the camloc route as well. I understand there are delays with the Skybolt kit, but has anybody used the following? They are slightly cheaper than the Skybolt, and they claim to ship with 24 hours. Would appreciate feedback from anyone else on the list. They have an RV kit, so I assume some RVers have used them.

http://www.milspecproducts.com/cowlkits.htm#rv

Dave,

BTW...you stink. I remember way back when when we were at the same point. Based on your pictures, it looks like you have blown by me. Looks good.

Scott
7A Fuse

Scott, these appear to be the same thing, with same prices as Skybolt. (same "part #" as shown on Skybolt site).

I wish I was that far along, but those aren't my pictures. They're from Pete James down under. I just posted them here, because they might be helpful for anybody going the camloc route.

BTW, Pete used hinge pins along the horizontal side seams. He only used the camlocs for the cowl/fuse seam.

In my opinion, the hinge installation is the slickest, prettiest and cheapest. (My opinion.)
That being said, some people have had problems with them, as mentioned earlier. I did have problems with the hinge eyes on the lower cowl sections where the exhaust pulses caused broken eyelets, so I went with screws and nut plates there; however, never had problems on any of the other hinges and I think they are easier and quicker to remove and install than camlocks. I have also seen some camlock installations that have bulging between the camlocks.
There is a method to installing the hinges though, so that there is no tension on the hinges when installed. I clecoed the hinges to the cowl (Hinges on the firewall should be already riveted on.) and made sure everything was installed correctly and all pins went in and out smoothly. (This is critical.) Then, use VAN's method to epoxy the hinges in place. Use peel ply to cover all of the epoxy while the hinges are clecoed on and reinstall the cowling on the aircraft. Do the bottom cowl first and put it on the plane, then do the top cowl. Use the slow cure hardener for more time to work with the epoxy. Let the epoxy cure. (Don't go over board with the epoxy here or you can have a mess. Use flox to stiffen it up and be aware that you can always go back and hit those areas that need a little more, later. Be careful not to get epoxy in the hinge eyes.)
After that, you can remove the clecos and peel ply, pretty it up and worry about riveting later. After a few weeks of putting the cowl on and off for building, I finally countersunk all of the rivet holes and riveted the hinges. Very easy and looks very nice. On top of it all, the hinge pins are easy to install and there are no pressure points on the hinge eyes caused by deformed hinge sections while riveting.
Which ever way you decide to go, good luck!