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Airfoil selection

Anything to do with gliders & gliding.
Elliot Howells
Posts: 333
Joined: 18 Mar 2015, 08:18
Location: West Wales
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Airfoil selection

Post by Elliot Howells »

Hi all,

probably biting off more than I can chew, but I've decided to focus on the SZD36 Cobra for my first serious attempt at 3D modelling - at 1:2.8 she should be just about big enough to be truly difficult to live with...

Now I'm no aeronautics expert, but the FX profile looks too thick to make a satisfying model to me, so I was thinking of something a little more slippery like an RG15 - my experience of Rolf's foil being that it's quite benign, and also something approaching the right outline, my B4 just won't pick up her skirts and has a very similar profile to the FX, albeit a NACA.

Any thoughts/ suggestions would be most welcome.

Ta, Ell.
Chris Veitch
Posts: 47
Joined: 21 Mar 2015, 07:57
Location: Northallerton, North Yorkshire

Re: Airfoil selection

Post by Chris Veitch »

Hi Elliott

I am somewhat like you and not an airfoil expert, but can comment that the RG15 sounds a good choice for this model. I still have a Purbeck ASW 27, which is currently awaiting some love time, that I really enjoyed flying. It had a RG 15 section and went really well.

Regards
Chris
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Cliff Evans
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Location: Bristol
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Re: Airfoil selection

Post by Cliff Evans »

The HQ 2,5/12 that we used on the Pat Teakle Salto would be quite a good choice. Good lift and if you want it to be it can be quite slippery. The Valenta Salto uses this section as well.

HQ 2,5-12.pdf
(47.21 KiB) Downloaded 74 times
https://lasercutsailplanes.co.uk
https://patteaklegliders.co.uk
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Peter Balcombe
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Location: Clevedon, North Somerset, U.K.

Re: Airfoil selection

Post by Peter Balcombe »

Cliff Evans wrote: 01 Apr 2022, 23:41 The HQ 2,5/12 that we used on the Pat Teakle Salto would be quite a good choice. Good lift and if you want it to be it can be quite slippery. The Valenta Salto uses this section as well.
Cliff,
I think we actually used HQW2.5 rather than HQ on the Salto.
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Cliff Evans
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Location: Bristol
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Re: Airfoil selection

Post by Cliff Evans »

Peter Balcombe wrote: 02 Apr 2022, 17:37
Cliff Evans wrote: 01 Apr 2022, 23:41 The HQ 2,5/12 that we used on the Pat Teakle Salto would be quite a good choice. Good lift and if you want it to be it can be quite slippery. The Valenta Salto uses this section as well.
Cliff,
I think we actually used HQW2.5 rather than HQ on the Salto.
I think that they are one and the same PDF HQW-2,5/12 used on the Salto and the HQ 2,5/12 produced by Profilli..

HQ - HQW Sections.pdf
(47.29 KiB) Downloaded 67 times
https://lasercutsailplanes.co.uk
https://patteaklegliders.co.uk
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RobbieB
Posts: 547
Joined: 07 Mar 2015, 22:22
Location: North West

Re: Airfoil selection

Post by RobbieB »

Well not exactly. The HQW series is a later, modified equivalent HQ section designed specifically for flapped wings.

Comparing the two it would seem the HQW sections have their point of maximum camber shifted further aft.

Whether in the real world you would notice any difference is anyone's guess.
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