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Old 10-23-2007, 06:26 PM
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My First Design . . . Updates 2

More updates,
Pretty unhappy with the final airframe weight of 3.25 oz. Going to make some changes already. Going to reduce the wingspan and fuse length by 5" so wingspan would be 28" with a fuse length of 30". Also reducing chord of main wings to 8 1/2". Stab will stay the same. Distance between wings will be reduced by 2". Also, next version should be machine cut to help prevent me screwing stuff up. LOL

What glue are you guys using to buid these F3P planes? I used regular CA, but wasnt sure if there was something a little lighter maybe? I only tacked parts together, to save weight on glue, so I'm not sure where all of the weight came from.

Will still fly it, probably at the JR Fest if I can get my electronics and motor by then . . .

Seth
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Old 10-23-2007, 06:38 PM
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Looks kewl Seth!

I can see 2 opportunities right now. You can make the carbon in the bracing smaller to save some weight, and trimming the ends will reduce it a tiny bit as well (also prevents snagging).

The other is the firewall. I bet it will pop off on the first snaproll you do if you run a big prop. A quick fix would be to drill a hole left and right of the center (outside of the contact area of the motor). Drill the hole slightly smaller than the carbon bracing you are using. Drill the hole so that bracing poked through the hole would be flat on the shockie portion of the fuse (or the upright). Then poke in a scrap of carbon and glue it in place on the fuse and to the firewall...
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Old 10-23-2007, 06:53 PM
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Okay thanks! I used .050" what size would you recommend? The Carbon for the landing gear is .070" probably could go down to .050" on it?

Before I added Carbon, the plane weighed 3.15 oz with the landing gear on it . . .
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Old 10-23-2007, 07:47 PM
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GiantStyle Yapoleno Hucker!
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3.15ozs, but what is the wing area? Keep in mind wingloading is everything. You can build a very small airplane that weighs very little, but what would the wingloading be....

On the carbon, I'd go ahead and drop to .030 or .040 on the bracing and .050 or .060 on the gear. Pushrods can be same as bracing if you have them supported in one or more locations down the fuse...
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Old 10-23-2007, 08:01 PM
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Okay! Modded the motor mount. I have .030" on my Sobre, but it seemed too small to use for the bracing. Will try that on the next one. Not sure what the wing area is . . . I believe around 400 sq. in.

Thanks for all of the help!
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Old 10-24-2007, 07:07 AM
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Actually, that is based on my plans . . . I forgot I changed my plans, so I should have around 450-475 sq in.

Seth
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Old 10-24-2007, 08:39 AM
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See, thats not a bad AUW then for that much wing area!
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