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Laser Airfoils

The Smithsonian National Air and Space Museum credits the Laser 200 for bringing about a new generation of aerobatic aircraft
youngman1
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Laser Airfoils

Post by youngman1 » Sun May 28, 2017 4:45 pm

Hi All

Does anyone have the non symmetrical 21012 airfoil? How does it fly compared to a fully symmetrical?

Thanks

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djpacro
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Re: Laser Airfoils

Post by djpacro » Sat Jun 10, 2017 9:33 pm

If you overlay profiles of the 0012 and the 21012 you will not see much difference. We bought a wing kit with ribs already cut but modified them by shaving a couple of mm (from memory that's all it was) off to give us a symmetrical wing although not exactly a 0012 (also note that near the root the spar was increased in depth so 13.5% or so from memory).

I don't have low Re WT 2D data offhand but at Re of about 8M there is a Clmax difference of about 0.03 and the zero lift angle of the 21012 is about -0.5 deg - not a lot of difference.

I've flown other Lasers with the 21012 and not noticed any difference (or at least any that I would attribute to the change in aerofoil camber).

Back then the competition sequences were predominantly outside figure so it made sense to have a symmetrical wing. These days the sequences are mainly positive G figures - would be interesting to do some calculations on the optimum aerofoil. One of my friends pushed a Pitts S-1D around serious competitions a few years ago and said he much preferred that over the S-1S.
Regards,
DJP

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