I have done both and the Skybolt fasteners are a lot easier to get a nice result. The hinge pins are a real PIA to do nicely and make them work smoothly. The cam locks only take about a minute more to remove and less time than a hinge system that binds. I do have hinges on the lower cowl sides and Skybolts on the upper cowl. Don
and hinge pins on the horizontal split. I like the cleaner look of the hinge pins, but the skybolts solve many of the common problems folks have around the firewall. I'll do it the same on my next build
When I built my -4, I installed the cowl with hinges per the plan. Hinges were a pain around the sharply curved firewall. When I started breaking eyelets, I replaced all hinge sections. At the firewall to upper cowl joint I switched to Skybolt fasteners and have been very happy with the results. Along the upper-to-lower cowl joint, I elected to stay with hinges. I had a number of concerns (real or otherwise) that helped make this decision. There is marginal clearance between the rocker valve covers and the cowl (O-360) and the quarter turn fasteners eat up a lot of space. Also, I was worried about bulging and puckering between fasteners.
The new hinges I installed are the extruded (rather than rolled) and slightly wider to provide more bond area so I expect a longer life for this install. These hinge sections are relatively straight, so pin installation is quite easy. I install the pins from the cockpit so there are no openings or additional fasteners on the cowl.
How many skybolt fasteners are required across the top rear cowling on a RV8? That's the only place I'm not happy with the hinge pins. Also, what width and thickness aluminum is required to make the scalloped mount for the female portion of the installation?
Skybolt fasteners are more sophisticated than the standard run-of-the-mill quarter turn. Skybolt offers a full line of fasteners having features that are well suited to our application, such as adjustable depth baskets, floating interface, stainless construction, wide contact flanges, etc.
The fasteners you see in my picture above are the SK245-4 floating type.
I put Skybolts along the top cowl firewall, then used hinges everywhere else, works very well. The only thing I wish I would have done differently is also used skybolts along the bottom lip of the bottom cowl, pulling the hinge pins around the exhaust and oil breather is a pain in the neck.
I've got 13 for the top cowl in the same locations as Bill, but only 4 of them (the two just above the longeron on each side) are floaters. The rest are fixed receptacles, meaning the cowl is somewhat more fixed. Works great. I don't know why Skybolt recommends so many floaters.
All the firewall flange receptacles for the bottom cowl are fixed.
On the next one I would use solid mounting strips for the lower cowl sides. With scalloped strips it is too easy to hook a corner of the lower cowl when lifting it into place.
I liked the Milspec so much on my -6A that I bought a full set for my -10. Plus, they were first out with a -10 kit, which Skybolt just recently got around to.
Actually, Patrick, we had our version of the RV10 Kit as part of our previous RV67910 Kits for quite a while. What we are learning from the RV10 projects is that cowling skins may be thinner than previous skins and that additional sets of fasteners better suit this cowling. Thus, we broke the RV10 Kits out from the standard 6, 7, and 9 Kits. We also changed the fastener configuration to address the thinner skin. I plan to do some design work with Sam James to find some good options for the RV10 cowling; possibly looking back at our Skybeam system that we used in the past. Skybolt has several ideas on the drawing board to introduce by SunNFun 2011. For now, Skybolt has new 2011 pricing on all Vans RV Kits and an additional 10% discount for OnLine Orders through January 1st.
Dan, the floating receptacles are a holdover from production aircraft that traditionally used floaters for the entire Cowling (big Cessnas, Barons, and so on). The Vans market versus the production market is different in many ways, but builder choice remains an important objective. We balanced the Skybolt kits to include floaters for the firewall and non-floaters for the sides to address "dynamic cowling shift" in flight. This is more tradition than recommendation. We will gladly substitute either receptacle in our kits.
Regards,
Ned
