identify this airfoil please

[skorski]

I have been trying to identify this airfoil for a couple weeks now, i've compared it to my own collection of plots and to what i've found on the web, no luck! I've tried to get an answer from e-flight but nothing.
So I come in search of someone who knows the designation for the 'foil used on the ascent motorglider.
Thanks in advance for your help, call me CuriousAboutThisWingShapeThingie.....Mike. :)

[raptor22]

Is there a particular reason why you need to ID it?

[Ollie]

Maybe the airfoil has no name. You named E-flite as the manufacturer. Does she know which father? ;)

[Ollie]

More:
Do you mean by this?
http://www.redrockethobbies.com/PhotoGallery.asp?ProductCode=EFL1075&PhotoNumber=2#largerphoto

From the picture, the sag of the film between ribs does not closely define the airfoil. So the airfoil is not defined and not useful in wing performance prediction. Any crummy airfoil will do with round of leading edge, sharp trailing edge and changing mean camber and thickness between ribs.

[BMatthews]

'Fraid he's right. You can do as good as this by using a dowel at the front and a stick at the rear and draw a curve around your shoe sole.

It's highly likely that even at the main rib it has no specific shape that you can find in the databases. Reams of similar basic arched shapes have been used on models over the years. Just put the high point at about the 35 to 40% mark and draw a smooth curve.

For example the one on the Gentle Lady is one of Carl's old free flight airfoils moved over during his desire to get into RC gliding. Other than a Goldberg number that doesn't mean a thing there's nothing special at all about it other than it works decently enough for how it's used.

[skorski]

raptor22,
This foil has some interesting flight characteristics, in that i'm surprised by how fast it is for being undercambered. It seems to have characteristics similar to a much thinner 'foil, but a fairly mild stall.
I like to compare what i see while i'm flying to what the polars are. It's just a curiosity thing i guess but it's part of the enjoyment of the hobby for me.
And Ollie's right about the sag between the ribs degrading the aerodynamics of the original 'foil but that's what peaks my curiosity considering how the saggy thing flies. I'm a balsa builder and it wouldn't take me long to build a fully sheeted and capstripped wing this size. But before I did I would like to know what 'foil it is and wether there were any versions with flaps. I'm thinking that this 'foil started as something else and was built with a few degrees of flap droop built in. Howzzat!
AlwaysLookingForSomethingToFly! Mike.

[Ollie]

The good news for E-Flite Ascent Electric ARF Park Glider is
Wing Span: 54 in (1384 mm)
Wing Area: 331 sq in (21.4 dm²)
Overall Length: 32.375 in (822 mm)
Flying Weight: 19.5 oz (552.8 g)
and for a better wing you could build one with better airfoils, AG36 for the root, AG37 mid and AG38 tip airfoils.
http://www.charlesriverrc.org/articles/drela-airfoilshop/markdrela-ag-ht-airfoils.htm
Build the structure with D-tube sheeting, no stag between ribs and film covering flat facets of the airfoils. The AG airfoils are designed for no sag and this size wing and this type motor sailplane!

[space_case]

For example the one on the Gentle Lady is one of Carl's old free flight airfoils moved over during his desire to get into RC gliding.

I always thought it was the Clark-Y!

It's got a flat bottom, whatever it is.

[BMatthews]

I always thought it was the Clark-Y!

It's got a flat bottom, whatever it is.

No there really is only ONE actual ClarkY. But it's like talking about Jello vs gelatine deserts. The name has been so overused that many, many folks see a long flat bottom on an airfoil and just automatically think "ClarkY". But t'aint so by any means.

The airfoil Carl used first showed up on his mid 50's free flight models. One in particular that I know he used it on was the Hi-Thrust Viking 1/2A class kit.

[space_case]

No there really is only ONE actual ClarkY. But it's like talking about Jello vs gelatine deserts. The name has been so overused that many, many folks see a long flat bottom on an airfoil and just automatically think "ClarkY". But t'aint so by any means.

The airfoil Carl used first showed up on his mid 50's free flight models. One in particular that I know he used it on was the Hi-Thrust Viking 1/2A class kit.

Yes, I was aware that the Clark Y is a unique airfoil.

This is neat info though. The G.L. was my first RC airplane, and I've built several since.

[HELModels]

For what it might be worth, if you play around with xfoil and load up just about any airfoil and play with the GDES routine you can adjust the camber and thickness until the bottom goes flat. Voila, instant "Clark Y" ;)