ORIGINAL: wsmalley
I am hoping you are correct about the servo. This was a suggestion by someone else based on how he set up his '27'-though I don't know the facts how he did it. Some have put the actuator arm directly on the pivot tube. I have put the arm-or actuator- on the rear (like the full scale) of the taileron. This where I calculated the 'mass balance' point to be. The effort to move the surface that way is extremely light. I plan to 'imbed' the 'T' in the ply(1/8th light), make ribs, top and bottom, drill some lightening holes, and skin them with 1/64th ply. That stuff soaks the CA well and is tough as nails. The LG has taken me so long to design/buildthat it has slowed me down. I am building some 'scale' working disc brakes for it and have the rotor built and the caliper about done. The piston turned out to be easier than I thought. I use a short piece of 3/8th alum rod turned to hold an 'O' ring. So far it takes very little air pressure to make them work. The 'pads' have yet to be worked out. I am thinking of using some RC car pads to try, thus far I've tried sandpaper glued to the press plate to test the theory.
The wooden control horn for our kit is embedded into the elevon itself. The pivot only carries the weight of the tailplane and acts as a hinge. I attached the control arm directly to the elevon pivot on my Halair MiG-29, but I didn't like that. It worked okay, but made it a pain to remove the elevon.
Looking at the pic you posted, it looks like the control horn is located way aft of the pivot. If this is the case, then the only problem I can see is this arrangement will limit the amount of throw you'll get from the system and the tailplane will need a lot of throw for elevator action.
Wow! Home-made brakes, huh? Instead of sandpaper, try leather. I think that's what the early car builders used on their brakes and it won't wear out your rotor as quickly as sandpaper.
Dan