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Old 03-14-2008, 04:15 PM
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rmenke
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Default RE: Spring Air Advice (Patriot XL)


Troy:

I assume you also have the mounting template for the 1/4 ply mounting system. You can use a little thinner ply, but not by much as blind nuts are the best way to go. Have seen some use Sheet metal screws with no problem. To transfer the mount stresses to the wing, you will need to back each of the ribs the mount attatches to. The best way is to build light ply ribs and ca/epoxie them in place. Some triangle stock from the rib to the mount also helps. You want to keep your glue joints and joining surfaces tight as possible.

You want to keep the mount plate as close to the main wing spar as possible in a taildragger configuration. You may have to go with a trike system if you can not get the wheel to miss the main spar. You can bend a small angle in the LG wire to help miss the spar, but not much, th wheel needs to set relatively flat in the wing and be angled correctly for taxiing . Some toe out is ok, just not a bunch. The smaller wheels you use, the easier the install.

Ok, wheel/opening covers (doors) do help with the airflow and drag and also make things look nice. Most newbies will try to produce a cover that works well. They are a mechanical problems in keeping them adttatched to the LG wire as the air pressures on them in flight when coming down are high, and they tend to slip around like a sail. No big deal flying when both do the same thing at the same time, but when one slips into a sail position and the other does not, its almost like trying to fly a twin with one engine out. Its dooable, your chances improve with 3D experience. Also each time you land and bend the gear a little, you have to re-allign the system so it does not hang up. More difficult with a door attached to the LG wire. Yes, ypou can reinforce the wire so it does not bend, but those forces have got to go somewhere. Suggest you leave the door to a future time when you can devote time to building a CF composit door and get some experience with the things under your belt. My first retracts were hand built in the 60's on a bench vice, hack saw, drill press and good files, took around 6 months of R & D, better called trial and error, somehow got all 3 to work off one standard Pro-Line servo. Did wow the guys at pattern contests and cop some wins when points were close. Also embarrassing when your gear falls down on takeoff or landing.

There is some build pics around on the forum that may help. Do a search. ENJOY