Bearhawk LSA wing Plans build Caution .

[stinger]

I know some of you are building the LSA wing by now. I am making this statement in hopes of helping one not make the same mistake I made. I made the wing ribs as per the mylar page # 4 drawing and the compression strut with the aileron bell crank as per plans . I then aligned the spars as per page #17 in the small instruction book. The compression did not align properly so I tweaked it a little and all fell in place. I then did a little rib trimming . At this point I can't help myself, and I am starting to have a bad feeling . I called Bob Barrows and found out the spars are not aligned as per page #17 but by the oblique line on the mylar page #4. I found very little reference to this information . Good luck! Stinger

[BTAZ]

Are you building them flat on a bench or vertically in a "skinning frame"?

I do recall when I "mocked" things up on the bench the two spars couldn't be just set with their bottoms on the bench with the compression strut in place. I built my wings vertically in the frame and don't recall anything unusual about getting the compression strut to fit so at the time didn't think anything more about it but I can see how there could be a headache if building on a bench.

I do know the bottom of the front and rear spars are offset when the mounting holes are in line. This factored in to using a level to verify consistent alignment(I.E. no twist or wash out/in across the length) in that a small tab had to be clamped to the bottom of the level to compensate for the offset.

I also recall a discussion as to whether the front and rear spar to fuselage mounting holes were co-linear. I decided they should be as if they weren't then the description in the book regarding lining up the attach fittings on the fuselage for welding wouldn't make sense.

[stinger]

I am building the wing in the vertical mount. I have now learned the spar mounting holes should not align with a plumb bob and stated on page #17. When the spars are in there correct position the mylar sheet line is the plumb bob reference. I will start over again . Stinger

[SC Patrol 253]

Thanks for taking the time to share this info. I'm a few months behind you but I'm sure it will be helpful. RIght now, I am still drilling spar cap strips.

[bergy]

After months of agonizing I have decided to complete my Patrol to be as "LSA-like" as possible in the remainder of my project. I've talked with builders that have built their Patrol without flaps and found that their Patrols fly well, and they save quite a few pounds. I guess I could buy a set of LSA plans, but think I can get by with just a little additional information.
I have constructed ribs to fit in the wing flap area, I am in the process of flanging the lightening holes for these ribs

So could someone with LSA plans help me out ? Since the short nose-ribs have stiffeners, I assume that my new flap-ribs should have stiffeners as well. What I would like to know is ... How many stiffeners/rib? I assume they should be 0.025 1/2" angles bent out of 2024T3. I also assume that these flap-rips should be riveted to the rear spar with 0.032 attach-angles. Correct?

Also ... what thickness aluminum is recommended for the cowl on the LSA?

R

[stinger]

bergy, I will see if I can help. The nose ribs have one .020 stiffener. The aft rib is constructed from .020 aluminum. The aft wing rib has no stiffener. The aft spar to aft rib has a .025 attach angle. The cowling: top skin .032, sides and lower are .025 skin on the LSA. Stinger

[bergy]

Thanks.... Little lighter material than Patrol wings, but 500# less design weight too.

[bergy]

Love your recliner ... can you reach the coffee-pot from that position?