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Old 12-19-2011 | 06:29 AM
  #610  
kingaltair
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From: Asheville, NC
Default RE: SIMLA BUILD THREAD

HIGH EVERYONE

Seeing that everyone is talking about covering and painting is encouraging...it means you guys are getting closer to the final finish, equipment installation, and finally flying.

I'd like to return to the subject of building the wing just for a moment. I'll find the reference in the thread later, but basically I was saying I set out to weigh the wing balsa, (ribs, spars, and sheeting), and put all the heaviest pieces on the LEFT WING in order to avoid having to add weight to laterally balance. When you have a side-mounted engine, (right side), the left wing usually requires between 1-2 oz to balance that out. By deliberately placing the heaviest pieces on the left wing, you might be able to save those 1-2 ounces. I have now built two wings with this method...the Simla wing, and the new King Altair wing I posted earlier in this thread.

Now for the results...I finally got everything installed and all the linkages made, and "surprise, surprise"....the left wing was too heavy. I had to add almost as much weight to the right wing. The lesson to be learned is NOT TO PUT ALL the heaviest wood on one side, but instead, maybe about 2/3 of it. Both the Simla wing, and especially the Altair wing required weight on the right wing, (the supposedly "heavy side").

The good news overall was that I was able to shave a full 11oz from the previous weight of the King, with the final weight, (with an OS .91 FS in the nose) weighing in at 7lbs 10oz....not bad considering such a large plane, (clipped to 70 inch wingspan, and quite a long tail moment, the King is a large plane...see attached). I flew the Altair once a few days ago...amazing the difference a different wing makes to the flying characteristics...it's going to need to be retrimmed.

I still believe in weighing all the wood and putting MOST of the heavier wood on the left wing...like I said, maybe about 2/3 of it.

Later,
Duane
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