Techniques > Misc

HQ35/12 Airfoil

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joe:
Recently read an article in a mag about HQ35/12.The writer had used this profile on many sailplane to great effect.
It is aparently designed specifically for use with scale sailplanes.
It has a good level of efficiency and excellent low speed behaviour.
Where the root of many vintage gliders is quite thick.The thickness of the airfoil(thats the 12 part of 35/12) can be incressed at that point to say 16%and than tapered back to 12% at the tip.
All sound pretty good and apparently no need for washout!
Maybe worth looking into for a next project?

Fred:
Hi there,

On the Retroplane forum, there is a scale airfoil project going on.
We are lucky to have some professional Aerodynamist working with us !
The latest profile is the MS 535


Most of the vintage sailplanes are using the Go535. Mathieu (MS) have updated this profile for us with a bigger TE (easier to cut) and made some calculations for 3 thickness :


The file can be found  here : http://www.retroplane.net/forum/download.php?id=177

A second profile has been developped : The MS Retro. Flat profile, a bit like the ClarkY, but once again, developped for our scaled use. Easy to build also with a big TE too :


And the file, with 3 thicknesses can be downloaded here : http://www.retroplane.net/forum/download.php?id=26

If interrested, I can give you the use on the glider for each thickness.

Fred

Happy Days:
Okay chaps,

If the lift from an aerofoil is suposed to come from the camber on the underside, how does a flat bottomed wing creat lift?

IceWind:
There is more in it than the camber. :)
If not how a flat wing shockflyer would fly.

Alan_Perse:
Hi Happy Days. Welcome to the forum.

A wing can still have camber with out having a curve on the botton of the wing. I'll try to explane with the diagram at the bottom. The straight line distance (the blue line) from the leading edge of the wing to the traling edge is called the chord line. The line that is equally distant from the top surface and the bottom surface (the red line) is called the camber line. The maxium distance between the chord and camber line is the camber of the wing.
Also, hopefully this won't mess things up  :D , a wing does not have to have camber to creat lift. It's the angle that the wing meets the air at (called the angle of attack) which creats lift.
Hope this helps.

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