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All Forums >> RC Airplanes >> Scratch Building, Aircraft Design, 3D/CAD >> Freeware airfoil program?
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Freeware airfoil program? - 3/24/2002 9:49:45 AM   
MiL



Posts: 281
Joined: 1/22/2002
From: Bend, OR, USA
Status: offline 		I'm looking for a program that i can use to print out airfoil rib templates. I'm aware of compufoil but i'm looking for something free. Is there anything out there?

Thanks
MiL
       Post #: 1

Freeware airfoil program? - 3/24/2002 11:18:43 AM   
erwinf


 

Posts: 29
Joined: 3/24/2002
From: Sucat Paranaque Philippines
Status: offline 		You can try Stefano Duranti's Profili 1.2, it's free.

Here's a link -> http://www.baronerosso.net/software/profili/profili1_2.htm

(in reply to MiL)
       Post #: 2

Freeware airfoil program? - 3/24/2002 12:56:28 PM   
MiL



Posts: 281
Joined: 1/22/2002
From: Bend, OR, USA
Status: offline 		also, how should i go about choosing an airfoil? Or creating one as the case may be.

I'm designing a small funfly plane for a .25 bushing motor. It will have around a 35" span and aspect ratio of 2.7 for a chord of about 13". Or at least those are the numbers i've come up with, they're similar to the morris pen knife, which is a comparably sized fun fly plane.

i dont know what kind of airfoil to use though. I tried that Profili program and created a NACA 0019 (thanks erwinf!) , that looks like a start anyway. This is my first design project and i'm not sure what i need. I want it to be very stall resistant (blunt leading edge right?) make lots of lift for a low wing loading and good low speed handling ( = very fat airfoil right?). Oh, and i want it to be symmetrical.

I want this to be a plane that i will fly in very low, close, and slow.

(in reply to MiL)
       Post #: 3

Freeware airfoil program? - 3/24/2002 1:48:33 PM   
erwinf


 

Posts: 29
Joined: 3/24/2002
From: Sucat Paranaque Philippines
Status: offline 		A blunt and fat airfoil would usually be the answer. Try watching how other planes with the same airfoil perform.

Here's a link to some videos from a japanese site -> http://www23.tok2.com/home/cha2/movie/movieindex.htm

Try viewing the 2nd, 3rd, 7th, 8th, 9th, 10th, and 11th links. These are videos of the Koma Fun 15 which has a very blunt and fat airfoil and I think they have built a .25 size model by stretching the wingspan and fuse lenth a bit.

Hope this helps.

(in reply to MiL)
       Post #: 4

Freeware airfoil program? - 4/8/2002 4:00:12 AM   
KC10Chief



Posts: 107
Joined: 4/6/2002
From: Tinker AFB, OK, USA
Status: offline 		MiL, instead of the NACA 0019, I would recommend the Eppler 473. I used it on the big fun fly pictured below. This is a 1.20 size fun fly and it flies great! The 0019 will work, but the Eppler 473 was made for fun fly's. They have it on Profili. Profili is an excellent program. It's all I ever use. Compufoil is a waste of money as far as I'm concerned! Matt

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       Post #: 5

Freeware airfoil program? - 4/8/2002 8:44:42 AM   
MiL



Posts: 281
Joined: 1/22/2002
From: Bend, OR, USA
Status: offline 		i saw that in another thread, i even loaded up profili and saved the E473 under another name that i would recognize when looking for it.

I've already built my plane with the 0019 though. I think the profile i used is a little skinnier which from what i've seen i think may be better on a smaller model like mine. I'm not positive about this, but somehow i kind of picked up the idea that smaller models don't respond as well to very thick airfoils as well as large models do. If this plane turns out to work well, i might build a bigger one for my Enya .49. If i do, i will be tempted to make a VERY fat airfoil, maybe even with a constant radius arc for the LE from top spar to bottom, just to see how it works.

Anyway, thanks for the tip... back to the garage, all i gotta do is finish hooking up linkages, cover the ailerons, and mount the fuel tank and my .25 FF will be ready to go.

(in reply to MiL)
       Post #: 6

Airfoil Program - 4/9/2002 2:08:12 AM   
Skids-RCU



Posts: 14
Joined: 4/4/2002
From: Fishers, IN, USA
Status: offline 		MiL,
I happened across a website that sells an airfoil design program that looks pretty interesting. I down loaded the evaluation version (for free) and played around with it a little bit. That was some time ago and they have since made revisions to it.
I was able to design my own airfoil, scale it and then print it out. You can also do wing design layouts and I think they even offer some basic airfoils you can start with.
Their website is: [url]www.winfoil.com.[/url]

Skids


(in reply to MiL)
       Post #: 7

Freeware airfoil program? - 4/9/2002 2:28:34 AM   
KC10Chief



Posts: 107
Joined: 4/6/2002
From: Tinker AFB, OK, USA
Status: offline 		Skids, Profili does all that you described about winfoil, and the best part is, it's free! You can design your own airfoil, scale it, make ribs for an entire wing, blend your ribs from root to tip, and they not only give you a few ribs to choose from, but they give you thousands of ribs to choose from! It's awesome that such a great program like this is free. Really easy to use too. You just have to convert mm to inches unless you like using millimeters. I'd never pay for winfoil. Profili offers all sorts of airfoils, even airfoils for planes like the 737, B-52, whatever. Check it out. Matt

(in reply to MiL)
       Post #: 8

Airfoil selection - 4/9/2002 4:16:06 AM   
Ollie


 

Posts: 958
Joined: 12/8/2001
From: Punta Gorda, FL
Status: offline 		The type of model you describe flies mainly on the prop rather than the wing. Any symmetrical airfoil that produces lift will do. You don't have to select the airfoil for its drag characteristics because the induced drag of the low aspect ratio dominates the drag budget. You don't have to select the stall characteristic because the rectangular low aspect ratio planform is almost stall proof. The airfoil selection and accuracy, in this case, is relatively unimportant because most of the wing is operating in the cross flow of the tip vortex and the rest of the wing is operating in the turbulence of the prop wash. This type of aircraft is about light weight, high thrust and generous control responces, not airfoil subtlety or precision. When this type of plane is doing its dramatic tail dance hanging on the prop, the wing isn't even producing any net lift.

< Message edited by Ollie -- Apr 8 2002 11:29PM >

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Regards, Ollie

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       Post #: 9

Freeware airfoil program? - 4/9/2002 8:26:28 AM   
MiL



Posts: 281
Joined: 1/22/2002
From: Bend, OR, USA
Status: offline 		Well, i took my new plane out for the maiden flight today. Flew great, better than i ever expected for my first design and scratch build. I only got one 5 minute flight in before it got too dark to fly, but it felt pretty good. Slows down to a crawl, roll rate is insane, stall was pretty gentle and occured incredibly slow. I didnt do too much vertical stuff but it should be unlimited and with a better prop capable of hovering and such. I have an OS 25FP with a 9x6 master airscrew right now. I'm thinking a 10x3 or 4 APC should really give it some thrust.

Can't wait to get it all trimmed up and dialed in tomorrow...

(in reply to MiL)
       Post #: 10

Freeware airfoil program? - 4/9/2002 10:13:20 AM   
Someone11-RCU



Posts: 394
Joined: 2/3/2002
From: Fresno, CA, USA
Status: offline 		There are so many airfoils to choose from with Stefano Duranti's Profili 1.2 ... in fact, it's overkill Best of luck

-Brian

_____________________________

Thanks for the forums!

(in reply to MiL)
       Post #: 11

Freeware airfoil program? - 4/11/2002 7:38:50 AM   
MiL



Posts: 281
Joined: 1/22/2002
From: Bend, OR, USA
Status: offline 		I made a webpage with info about my planes. Theres a link in my signature.

You can download plans for the .25 fun fly there. I've named it the Taco .25

(in reply to MiL)
       Post #: 12

Freeware airfoil program? - 4/12/2002 7:53:38 AM   
rmkearbey


 

Posts: 15
Joined: 4/5/2002
From: Loma Linda, CA,
Status: offline 		You guys are great! I've been wanting compufoil for awhile now, but didn't want to shell out the money. The profili program will work perfectly! Now I'm just wondering how one selects an airfoil from the long list. Such as, which is the fastest (faster) and which are more ideal for slower or soaring applications. Is there a way to group them into such categories, or do you have to scroll through each one and use your own judgement? Listen to me, I get a free program and I'm picky about it already!!!!

(in reply to MiL)
       Post #: 13

Freeware airfoil program? - 4/12/2002 8:12:07 AM   
MiL



Posts: 281
Joined: 1/22/2002
From: Bend, OR, USA
Status: offline 		That is kind of a problem, you have to know what you're looking for. Profili is great for plotting airfoils, but it doesn't help you out too much when it comes to selecting one.

Obviously fat airfoils are better for slow flight and thin ones are better for high speeds, but beyond that i dont know too much.

(in reply to MiL)
       Post #: 14

Freeware airfoil program? - 4/12/2002 9:10:56 AM   
Someone11-RCU



Posts: 394
Joined: 2/3/2002
From: Fresno, CA, USA
Status: offline 		There has to be a website dedicated to types of airfoils, and what types of airfoils to choose for certain planes... does anyone know of one?

_____________________________

Thanks for the forums!

(in reply to MiL)
       Post #: 15

Freeware airfoil program? - 4/12/2002 2:22:07 PM   
Steve Lewin


 

Posts: 904
Joined: 3/18/2002
From: Reading, UNITED KINGDOM
Status: offline 		Warning - airfoil choice is far from simple.

But if you're seriously interested in how these things work try http://beadec1.ea.bs.dlr.de/Airfoils/theory.htm

Another useful resource is http://amber.aae.uiuc.edu/~m-selig/

It's particularly interesting to look at the "Incomplete Guide to Airfoil Usage" which lists the airfoils used by a huge number of full-size aircraft. You should get some hints from that .

Steve

(in reply to MiL)