Eagler's Nest
Airframes => Single Seaters => Topic started by: 3D2 on June 09, 2021, 09:44:54 PM
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Yes or no,
IIRC: "all things being equal" on airfoils with an identical upper surface, the one with an undercamber will produce more lift than the one with a flat bottom and as a result in level flight will stall at a lower speed. Thanks
(Published wing plan offers both options.)
Thanks
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Google is your friend... O:-)
(https://i.stack.imgur.com/nNcxy.png)
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Google is your friend... O:-)
(https://i.stack.imgur.com/nNcxy.png)
Yes,perhaps I was too brief in my OP. The airfoil on my RW-2 is nearly symetrical but differs from the Google example of semi-symetrical, in that if you use the line of thrust as a datum, the leading edge droops to a position where the airfoil is actually just barley undercambered. But it has 50 hp propelling 505 pounds all up (10.1 #/hp).
To pull 425 pounds with 38 hp (11.2 #/hp) and keep the stall speed under the mandated 27.6 mph I wanted to make certain that the extra 0.2 lift points given on the 36 were real. So a better way to ask might be:
Does anyone disagree with the following: when the lift of an airfoil increases the stall speed ALWAYS decreases...
(Yeah, it gets nastier when it finally comes and there is more adverse yaw, but I'm not asking that.)
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Food for thought:
https://www.quora.com/Is-it-best-to-use-a-thick-airfoil-or-an-undercambered-airfoill-for-a-slow-speed-flight (https://www.quora.com/Is-it-best-to-use-a-thick-airfoil-or-an-undercambered-airfoill-for-a-slow-speed-flight)