Get fiberglass and don't worry
Ok, I'm almost done here and thought I should put the gear fairings on before I roll it out the door.
Go fly with out them. Yes
Look you are going to have to do some rigging right, aileron, flaps and so on. The gear leg fairings are powerful airfoils. Go fly and get the plane rigged and than put the gear legs on with or with out the wheel fairings. Go fly and see if it changes how it fly's, e.g., skidding, rolling. With them on you don't know what is out of kilter.
Most of the time I read the instructions, look at the drawings, find and identify all the parts...assemble. I'm drawing a blank on these gear fairings tho. Drawing C2 out of the rv-4 manual shows part # u-810 a 1/16th of an inch from the brake disk. (this is the braket that attaches the fairing to the gear) This works fine, if the brakes aren't installed!!
Anyone have pictures of this bracket installed with the brakes? I'm just not seein' it. Thanks!
First, if you still have metal gear leg fairings you may want to pop for the new fiberglass ones, since they have a wider chord, thus more aerodynamic (less drag) and good for a mph or so more. Also that mid leg overlap is ugly. Also the fiberglass ones have a simpler method if securing with hose clamps.
I forgot what the "classic dwg's" said but I recall they left something to be desired and where vague as you are finding out. I'll give you some random thoughts below. Not sure what you are asking but it may give you some inspiration?
The Goal
You need to do two things, keep the fairing from rotating and sliding down. The rotation is helped by the upper and lower gear leg intersection fairings you eventually glass-up. There are many ways to do these. To keep it sliding down can be done several ways as well. In general the wheel pants and lower cuff keep the gear legs from sliding down. The new gear leg fairing (fiberglass) are held by a notch in the fairing and hose clamp. The intersection fairing covers this up. I would get the wheel pants (with brakes) on first. There are many ways to install the gear leg and intersection fairings and have seen many a variation. However with the new fiberglass ones they use a hose clamp in notches to secure the fairing to gear leg, so it takes out some of the "creative" solutions.
Piano Hinge Wire or Bond
The piano hinge can be done several ways. My old RV-4 (with metal gear leg fairings) was set-up so the piano hinge came out the bottom. I had to jack the plane up, remove the wheel fairing, tire assy and brake caliper to snake the piano hinge wire out. What held the wire in / up? Friction. It tended to stay put, but if it work down a little it could not get far; it would just run into the wheel fairing or brake caliper. You can drill a little tiny hole in the hinge wire at the (top) end and safety wire if you want. I did not bother because it stayed put.
Bonding, an option: If you go or have fiberglass gear fairings, just bond the trailing edge together and forget the piano hinge all together. It's a semi-permanent installation so to speak. Frankly you should never need to remove the gear fairings, ever. If you have to remove them, you cut through the bond. It saves the weight of piano hinge hardware. The only time you might have to remove them is if you need to replace a gear leg or engine mount, which should be never. I flew bare metal for a bit and only removed the gear fairings to paint them. They went back on for +1000 hours until I sold the plane.
Wood Gear Stiffener
I'm not recommending wood gear stiffeners glassed onto the gear legs, but I had them on my RV-4. (They do firm up the ride a little, no doubt and help wheel shimmy if that's a problem. They add weight and are a pain; fly with out at first.) With the bonded on wood stiffeners, they basically keep the whole gear fairing from rotating or sliding down. You can even screw through the gear leg fairing into the wood stiffener. Again suggest you fly with out the stiffener for a while and determine if you want them. You'll want to do the bonded on wood stiffener first, before the gear leg fairing or intersection fairings any way. When you glass on the wood gear stiffener you change the dimension of the gear leg due to the glass plies, so it changes everything.
