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Old 02-10-2013, 07:02 PM
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wojtek's Avatar
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Location: nj, NJ
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Default RE: SkyMaster MB339 Build Thread

I hope these two photos of a new wing give an idea the way i marked them up ... sorry, but i have no visio here, so it was a manual drawing on them in PS, lol ..

The gear load will act like a pry bar on the mounts, one pulling out the other pushing up ( looking from the bottom of wing) . Because the ribs do not esist at the inboard and outboard section of the gear rails, this area is weak and has no support for this torsion pry load. You have to do all you can to reinforce this . There is a lot of room on niner side of the wing inboard from the retract mount. Its tight to get to, but worth the effort as this area will take the most load. Anyone that has seen gear push up has seen the upper skin crash here where there is no rib/former. Simalar to the outboard area of the rails. THe one mount could also use being supported with some triangle cut ply for structural strength. I have had tons of flights on grass, and the gear is not an issue at all with this set up. With all 3 tanks full, and around 50oz of smoke fluid on top of that with a P200 for power, my plane definitely was a pig hog on the gear, lol . ..

as for the wing mounts, i have done snaps and spins ( within the realm of what would be scale I guess ) , and never had any separation issues.. I would not trust a single small bolt per wing, and also i would not trust the aluminum tabs either without gluing these in myself. I have seen these pull out of the glue in the wing quite easily actually. I ended up pulling them out( by just heating them) and replacing with my own ..

I really need to get going on my 2nd MB339 after the 1st one went in running out of fuel :\

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