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Author Topic: Wing Airfoil Selection  (Read 1252 times)

Offline Adriano Gularte

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Wing Airfoil Selection
« on: November 08, 2022, 06:33:25 AM »
Hello Fellows from Stunthangar!

What is the best airfoil (simetrical) to use in a stunt airplane designed to use .35 to .40 engines?

Best Regards!
Adriano Gularte
Brazil

Offline Ken Culbertson

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Re: Wing Airfoil Selection
« Reply #1 on: November 08, 2022, 07:01:33 AM »
Now that is a subject that we all agree on.... LL~
To me, it is going to depend on a lot of factors.  What sort of .35 - 40?  Legacy like a Fox 35 (say no)?  What is your skill level?  Will you be flying hard corners?  How big will the plane be and how much will it weigh?  Flaps?  All of this, and more go into airfoil selection.  My recommendation - find a fairly recent designed that has a good record in that size and copy the airfoil.  Two very different ones that I have experience with are the Mustunt and the Vector series.  When that size motor was popular the Gieseke Nobler airfoil was "King of the Hill".  It is still a good choice. I would avoid any that are extra blunt, flat backed (ice cream cone) or thicker than 20% in that size motor.  This is just me and others may not agree.

Ken
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Offline Dennis Toth

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Re: Wing Airfoil Selection
« Reply #2 on: November 08, 2022, 07:38:53 AM »
Adriano,
Agree with most of what Ken said, for the Fox you would want to have a ship with 16 - 18% thickness and max span of 46 - 48", keep the weight below 40oz. Also if you use a Fox 35 with muffler cut the prop diameter to 9 1/4 - 9 1/2" to reduce load (heat) in the engine. If using a more current engine then what Ken said fits the bill, Vector is a good ship to look at.

Best,   DennisT

Offline Air Ministry .

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Re: Wing Airfoil Selection
« Reply #3 on: November 08, 2022, 05:57:09 PM »
This works good , & f ou shorten the rear by an inch ( 7 in. chord rather than 8 in. ) it gets fairfully modern .



Antique Fox .35 things were 36Oz. & unmuffled , Thinner low drag stuff , usually . Not that a Oriental isnt for a fox .35 .
but is good with a LA 46 etc .





or a o\more modern one thats the same . Theres a AIRFOIL thread or two , but it like cars & motorcycles
A XLCH isnt a Bultaco trials bike , but thats not to stop you trying , with it .


Offline Air Ministry .

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Re: Wing Airfoil Selection
« Reply #4 on: November 08, 2022, 06:03:37 PM »
Your actually best to ' RESTYLE ' a existing competant design , perhaps .







Twink , twink , glorious twink .



These suckers will carry a bit of weight . LIKE ANYTHING , building it light straight & true with ' solid ' controls
is essential if its to behave itself .


Offline Adriano Gularte

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Re: Wing Airfoil Selection
« Reply #5 on: November 09, 2022, 08:10:22 AM »
Thank you Guys for your answers and sugestions!
I haven´t flying Control line models sice 1990!
In the last weekend i flow an old model with an O.S. Max .15 III on it, and I became motivated to fly again the Control line models.
I like to design and build my planes, so I intend to design a model for the intermediate flyer to start practicing again.
The plane will have flaps and a profile fuselage to make the construction easier.
I have two engines to choose, an old FOX .35 and a brand new OS .40 LA.
I thought to use the Fox .35 in the begning and the OS .40 LA later when my abilities became better.
What´s your opinion about this guidelines?
 
Adriano Gularte
Brazil

Offline Ken Culbertson

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Re: Wing Airfoil Selection
« Reply #6 on: November 09, 2022, 08:30:38 AM »
Thank you Guys for your answers and sugestions!

I haven´t flying Control line models sice 1990!
In the last weekend i flow an old model with an O.S. Max .15 III on it, and I became motivated to fly again the Control line models.
I like to design and build my planes, so I intend to design a model for the intermediate flyer to start practicing again.
The plane will have flaps and a profile fuselage to make the construction easier.
I have two engines to choose, an old FOX .35 and a brand new OS .40 LA.
I thought to use the Fox .35 in the begning and the OS .40 LA later when my abilities became better.
What´s your opinion about this guidelines?
 
If the FOX is reliable it will be OK if it is a newer one.  On a profile you will have to deal with the unnerving "Burp" of a FOX.  The motor appears to quit then comes back.  The OS is more reliable and considerably more powerful and very polite (no burping).  If it were me I would use the OS.  Power when you are learning is very important.  I like to build my own as well.  If you want an airfoil appropriate to a profile for this size motor look at the SIG Twister/Banshee profiles.  The sharp LE of the 60's designs is not the best you can do. 

Ken
AMA 15382
If it is not broke, don't fix it.
USAF 1968-1974 TAC

Offline Ken Culbertson

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Re: Wing Airfoil Selection
« Reply #7 on: November 09, 2022, 08:36:59 AM »
If the FOX is reliable it will be OK if it is a newer one.  On a profile you will have to deal with the unnerving "Burp" of a FOX.  The motor appears to quit then comes back.  The OS is more reliable and considerably more powerful and very polite (no burping).  If it were me I would use the OS.  Power when you are learning is very important.  I like to build my own as well.  If you want an airfoil appropriate to a profile for this size motor look at the SIG Twister/Banshee profiles.  The sharp LE of the 60's designs is not the best you can do.  A slightly thinner version of the Thunderbolt above would be a good choice.  I use that one on my profile and the thicker one on my PA.

Ken
AMA 15382
If it is not broke, don't fix it.
USAF 1968-1974 TAC

Offline Adriano Gularte

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Re: Wing Airfoil Selection
« Reply #8 on: November 09, 2022, 06:11:19 PM »
Ok Ken, I will follow your advice and use the OS .40 LA engine.
I found a Sig Twister plan on internet and downloaded it, I think that I have all I need to start my project.
I will post some pictures here after the plane is ready.
Best Regards!
Adriano Gularte
Brazil

Offline Ken Culbertson

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Re: Wing Airfoil Selection
« Reply #9 on: November 09, 2022, 08:14:47 PM »
Ok Ken, I will follow your advice and use the OS .40 LA engine.
I found a Sig Twister plan on internet and downloaded it, I think that I have all I need to start my project.
I will post some pictures here after the plane is ready.
Best Regards!
If you are building one from plans I would do two things.  The wing warps easily.  I would plank the LE up to the spar and round the LE a bit more than the plans show.   

Good Luck - Ken
AMA 15382
If it is not broke, don't fix it.
USAF 1968-1974 TAC

Online Brent Williams

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    • Fancher Handles - Presented by Brent Williams
Re: Wing Airfoil Selection
« Reply #10 on: November 09, 2022, 09:37:06 PM »
If he has an LA40 available as the powerplant, there are plenty other common designs that are out there superior to the Twister with more wing area and a better overall design.  No shade against the Twister.
Brodak profile Cardinal 40, Legacy 40, Pathfinder, Chipmunk, Vector 40, Imitation, just to name a few of the many. 
« Last Edit: November 09, 2022, 10:16:06 PM by Brent Williams »
Laser-cut, "Ted Fancher Precision-Pro" Hard Point Handle Kits are available again.  PM for info.
https://stunthanger.com/smf/brent-williams'-fancher-handles-and-cl-parts/ted-fancher's-precision-pro-handle-kit-by-brent-williams-information/

Offline Air Ministry .

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Re: Wing Airfoil Selection
« Reply #11 on: November 09, 2022, 09:41:50 PM »
This is a 1/4 Sq L E with 1 / 16 sheeting . ( Oriental , Patternmaster etc etc )



https://stunthanger.com/smf/gettin-all-amp'ed-up!/big-jim-banshee-build/msg493672/#msg493672

" Let me tell you about the pink Banshee.
1)   54” span equal panels
2)   Half ribs to spar with vertical webbing between spars
3)   Adjustable Tip weight box and movable leadouts
4)   Flat wing tips
5)   8 1/4” nose
6)   ¼” stab and elevator tapered to tips 261/2” span
7)   Diamond shaped Fuselage with the top and bottom end 1/8” thick
8)   Barn door flaps 2 ½” to 1 ¾”
9)   Motor Fox 35 running on missile mist fuel no muffler
10)    Custom landing gear 1/8” music wire eighth banner racing wheels
11)    Custom Big jim Tank
12)    Leading edge radius (NOT TO BLUNT JIM DID NOT LIKE TO BLUNT LEADING EDGE.)
 NOTE : you had to hear that Fox run it sounded like a formula one motor with about 10 different gears.  In the Horizontal square eight this motor changed speed for every leg.
 Big Jim first flight on the Banshee.(BTW the other flyer was Big Jims close friend RAY MOORE.) Big Jim firers up the Fox and proceeds to fly a very impressive pattern that looks like Gene Schafer. I had never seen a profile fly like a full bogie stunt plane. The engine quits and proceeds to wind fly. Lazy eights, inside loops ,outside loops, inside square and one triangle. Milton and I had seen Bob and Gene wind fly but not like this.

Jose Modesto "

Just to further confuse the issue .



Banshee top , Twister Bottom .

file:///C:/Users/PublicInternet/Downloads/Griffin%20Banshee.pdf  PLAN LINK , link to Twister Vs Banshee below .
                                                                                                ========
https://stunthanger.com/smf/open-forum/twister-vs-banshee/msg535461/#msg535461

RRRRRR , theres a DOWNLOAD for the BANSHHE there ;

Brent Williams , reply 72 . CLICK on the bottom thingo .  H^^





Offline Air Ministry .

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Re: Wing Airfoil Selection
« Reply #12 on: November 09, 2022, 09:52:00 PM »
Did someone mention CARDINAL .Profile Plan THERE .

https://stunthanger.com/smf/open-forum/windy's-profile-cardinal/msg568125/#msg568125

Sgota fairly usefull airfoil .



True things outer cardinal 92 ribs . vailable laser cut . you LOOSE the center few , Like THIS /. https://stunthanger.com/smf/nostalgia-30/gieseke-nobler-46/msg613419/#msg613419

Post 54 here gives you some dimensions to Suit a LA 40 / 46 , if you wanna go the Greenaway way . https://stunthanger.com/smf/nostalgia-30/big-jim's-n30-designs-patternmsater/50/

Thick Wing means good support , easier slower flight , maybe . LASER CUT Ribs , unless your a rib afficionado , are a big ' accuracy ' ensurer . You want a few jigs / blocks / packers & suchlike .

https://stunthanger.com/smf/open-forum/cardinal-profile-vs-pathfinder-profile-some-of-your-thoughts-please/

Damp marshy grounds safer than sun baked concrette , if youre tripping over things for a while .





« Last Edit: November 09, 2022, 10:12:04 PM by Air Ministry . »

Offline Dennis Toth

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Re: Wing Airfoil Selection
« Reply #13 on: November 19, 2022, 07:25:15 AM »
Adrianno,
A good starting point would be a Fanchized Twister for basic layout and numbers. Would work for the LA 40. The Fox needs a little smaller ship you could reduce the number to match as a 46" span or do a Tutor with a bit thicker wing, but keep it light with good wood and a light (like UltraCote) finish. To use the film covering you should plank the last section of the wings (wing tip bay) with 1/16" balsa to get the rigidity (this is the way the original Tutor wing was done, it was designed for film covering and works really well.

Here are the plans:
Fancherized Twister
https://outerzone.co.uk/plan_details.asp?ID=8708
Tutor
https://outerzone.co.uk/plan_details.asp?ID=11400

Best,   DennisT

Online Brett Buck

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Re: Wing Airfoil Selection
« Reply #14 on: November 19, 2022, 01:58:14 PM »
The Fox needs a little smaller ship you could reduce the number to match as a 46" span or do a Tutor with a bit thicker wing, but keep it light with good wood and a light (like UltraCote) finish. To use the film covering you should plank the last section of the wings (wing tip bay) with 1/16" balsa to get the rigidity (this is the way the original Tutor wing was done, it was designed for film covering and works really well.


   I am not sure why you want to make the Tutor wing thicker, it is a quite excellent proportions, size,  and shape for a Fox and nearly ideal for a 20FP or 25LA. I would make only one change to the original Tutor plans, make the stabilizer about 30% bigger and leave the elevators alone. With good wood, the stock kits built to extremely good weight - I had two of them, from the kit, one weighed 27 ounces with a Fox 35, the other one weighed something like 30 ounces with a ST46.

    Note that I mean the *original* Tutor, from the kit, not the ARF version, which is vastly larger - as in the plans Dennis posted above.

      Brett

Offline Dennis Toth

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Re: Wing Airfoil Selection
« Reply #15 on: November 19, 2022, 08:02:01 PM »
The Tutor plans posted are for the original but they didn't have the tip section planked. There was a rather long thread on this some months back and the ship posted is pretty close to the original at least for a practice ship. The larger one is the Tutor II and as Brett said it is much larger and not for either the Fox 35 or the LA 40.

Best,  DennisT


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