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Glider flap hinge options


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On 05/01/2022 at 10:10, David Ramsden said:

Thanks Don, Pat, and Simon,

Pat, with your ABC flap/spolier setup, I'm surprised that in position B the model gained more (in lift) than it lost (in drag) but that actually makes me think that with the simple bottom-hinge setup I am thinking of (as per diagram at top of thread) the same would be true (at 10 degrees down I'd gain more than I lost) and so a top-gap-cover is unnecessary. Mind you, I rather like the gap cover on your ailerons. I saw an advert recently for plastic draught excluder tape on a roll which was very thin and self adhesive down one side. Maybe that would work.

Simon, I'm not entirely sure what "off set pivot points and matching profiles between the wing and flap" would look like. Is it weaker and more complicated than a full-length simple film hinge?

Please excuse my ignorance.

 

David 

David, increasing the drag doesn't do anything to "cancel" the lift. What it does is steepens the glide angle (expressed as a ratio the glide angle =  lift/drag) & slows the model down. This means that although the model is descending at a steeper angle the actual rate of descent is less than when flying at it's previous speed. When circling in a thermal the rate of descent is what's important, a low forward velocity desirable as the model can turn in a tighter radius in order to remain within the thermal.    

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  • 4 weeks later...

Hi again. So, I finished the wing center-section, bottom-hinged the flaps with the covering film, and added gap cover tape I bought from Hyperflight. I had a couple of problems with the tape and Neil at Hyperflight very kindly gave me a refund. After a few attempts and a lot of fiddling I decided best thing to do was cut the tape down to 15mm leaving 10mm of adhesive and only 5mm of clear tape to cover the gap. I'm still not entirely happy with it but it's easy to peel off and re-do. Here's the result so far; flaps up; about 7 degrees down; about 15 degrees down, and all the way down which is about 80 degrees.

 

IMG_20220129_143633.thumb.jpg.5895dbd8c1ba8ce47fd1bba6487b07d9.jpg

 

IMG_20220129_143641.thumb.jpg.27bb3ef8ac25a6767a3f06533c6fbc8c.jpg

 

IMG_20220129_143648.thumb.jpg.8826829915e28384feaa0b47b5715848.jpg

 

IMG_20220129_143653.thumb.jpg.92932fd1d6ffcd8138ef08ab04a27402.jpg

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