sir crashallot

does anyone know the scale aerofoil section used on the full scale wing and tail of the p51d mustang as im starting to collect details and info for a future build, thanks for any input you guys have

wellss

Check the UIUC Airfoil Coordinates Database

http://www.ae.uiuc.edu/m-selig/ads/coord_database.html

BMatthews

The scale airfoil is a fairly critical laminar flow type. At our Reynolds numbers it won't perform the way it does on the full sized airplane. For the sake of nicer flying manners I'd suggest you skip on it and go with something that is more low Rn friendly. Or at least get some first hand reports from someone that may have used the exact scale airfoils.

HighPlains

My Feedback: (1)

For what it's worth, the D used NAA/NACA 45-100 developed for the Mustang.

funkworks

BM took the words right outta my mouth... An airfoil modified for rc use would be a better choice.

Bax

My Feedback: (11)

Experience has shown that this is a very good way to go. Top Flite started their use on the P-47 Gold Edition and kept with them. They're airfoils designed by Dr. Mike Selig especially for scale R/C use.

Airfoils: Root: S8036
Tip S8037

sir crashallot

thank you everyone for your input i will use the s8036 and 7 aerofoils. if anyone else has any info relating to the p51s aerodynamics please post it in here for me. also thanks to the mods also for there time

topspeed

Mustang is perhaps the aircraft that suffers most when made into a small size.

http://www.aviation-history.com/theory/lam-flow.htm

You cannot make the wing laminar...nor can you get the ram air working.

sir crashallot

ram air are you refering to geting the big scoop that leads to the radiater under the rear wing?
i have printed the mustang out with tileprint and i set it to print the fuselage to 60 inch from tip of spinner to end of the rudder. so i should have a fairly big wing and not a small model by far.
TOPSPEED if you have any advice id be willing to hear it before i do eventualy start the build, for the moment i want to sort out what aerofoils and so forth il be using,

sir crashallot

you left out the spitfire there horrible when small and flying slow,
most warplanes where built to be on the edge to allow for such manouvering and sharp turning, heck it would be nice to fit some cannons to a extra 300 or to an edge and send them back in time to world war 2 that would have been a shocker for the german pilots.

rmh

Shocker? - You bet yer auntie's knickers - The EXTRA is by german, Walter Extra.
Whateva- scale airfoils non scale airfoils - the object is to get good performance in a model and the real trick -is to resolve the BIG problem -even in the full scale - theu were simply ALL too heavy when ready to go.
Fiddle with the shape til the cows come home - OR just learn to build ligher .
It fixes a multitude of sins
I built a 1/5 P51 from a "scale designers" kit -for a customer.
The shape was spot on but the construction ? absolutely the worst I have sever seen.
It may have been awkward and flimsy but at least it was heavy.

topspeed

Sir Crashallot,

How about this for a MUSTANG foil ? It looks just a tad like a real foil of P51D ( but due to re matter only a bit ).

sir crashallot

that looks like it should do the trick, so let me get this correct, that will be used as the master rib, secondly as the wing tapers in in size all i need to do is keep reducing it in size by shrinking it, also is there an airofoil section out there for the tailplane of the mustang thanks for all your input on this
kind regards Brent AKA sir crashallot

Ben Lanterman

As mentioned by Bill B. above I would stick with what the good Doctor suggested. He is terribly well versed in model aerodynamics and airfoils. Anything else is just coming in second. It might work but not as well.

Ben

sir crashallot

im thinking it will be the easiest. all i need to do is dig the topflite manual out with parts list picture blow up the parts sheet with ribs on and adjust to the sizes i need. also adopt there idea for the retracts rail. love it when a plan comes together

rmh

Maybe maybe not - may work every bit as well.
I would bet money -that if you simply make a strong light 24/12 section you could not tell the difference -
Not poo pooing the airfoils - just noting tha having done a LOT of various airfoils in light model s - I can't tell the difference.
th REAL differenece ?
the lighter ones always flew the best
not too strange tho if you think about it.

sir crashallot

right that ios more or less the wing sorted, tailplane now i want it to have a scale look so i want to build the tailplane up from ribs now does anyone have any ideas for the aerofoil section for the tail

Ben Lanterman

Dick that is not really a great way to pick an airfoil. The fact that a light airplane with a xxxx airfoil flies OK or that a heavy airplane might fly OK doesn't mean that the xxxx is the way to go if you are looking for a really good airfoil for a scale airplane.

The air does care how it goes around the airfoil at all angles of attack of the airplane. Remember the airplane will more than likely pull 8 to 10 g's in our model use which may be a high angle of attack. Why chance it when that light airplane suddenly isn't a light airplane any more and the angle of attack is very high.

If the xxxx airfoil gets to the angle of attack where separation will occur at an lower angle of attack than a very good designed airfoil - then it seems reasonable to use the well designed airfoil does it not? The good Doctor's theory of airfoils is backed up with enough actual testing to indicate whether or not time is wasted. Having seen the use of theoretical airfoils in actual practice I would be comfortable in using one especially if it has been used successfully in other scale models. It would make the light airplane all that much better.

It takes the same amount of time to trace around and cut the ribs either way.

For the tail - some symmetrical airfoil is going to be appropriate. That is a case where the scaled tail section would be OK.

Ben

sir crashallot

thats good then just a case of having a quick search for the section of the full size p51s tail. i didnt think it would be a problem but id rather check and back up my thoughts then build it and wreck it. thanks for the input guys and if anyone else has any comments about the aerodynamics with the p51 please put the info forward as it is all good to know about

rmh

The good Dr must work with the same problems you or I will see in a model
Why should he be able to predict a better airfoil for an unknown subject ?
That simply defies logic.
I say unknown because unless you have a Known power and weight and wing loading- all bets are off.
just because a shape is published as "good for P51" why should it be good for all P51 models The 2412 is really good for a simple reason
it is a shape which is easy to build - (no fancy curves) and is thick enough for a decent light structure to be used.
Now then if I did a scale P51 I would just use the scale shapes -or an eyeball version of it
it really makes no difference
What I would do tho -is work my fingers to the bone to loose every single ounce and gram.
I fly my models I don'tlike to herd them around .
I once flew a friend's scale subject a very pretty model at a meet and was stunned at how overloaded and underpowered it was . the airfoils could have been re engineered by any of your favorite experts and the results would have not improved
it was simply toooooo heavy.
If all the aerodynamic studies started with "make it as light as can be THEN pick a foil" the models would all be a lot easier and more fun to fly
(slope soarering machines excepted )
Today we went to the Point of The Mountian fot th e contest
30 mph wind straight up the slope - perfect!
these suckers were 7% foils all composite and went like hell
I came home with a mouth full of Utah desert and a dusty car.

Rotaryphile

I used an airfoil that was quite similar to scale Mustang wing airfoil on a sport pattern model, at 12% thickness, maximum thickness at 50% chord, and found that it tended to get into what seemed like incipient stall at much lower lift coefficients than the NACA 0012 airfoil used previously. The airplane tended to wander off track in maneuvers when the wing was forced to a lift coefficient over about 0.5, but was just fine for large radius maneuvers, and seemed faster than the 0012 airfoiled wing. I think that the Mustang's so-called laminar flow airfoil is better suited to much higher reynolds numbers and Mach numbers over about 0.7. I heard that a laminar flow airfoil was tried on a full-scale P-47, with negligible performance improvement.

rmh

look at the German fighters of the period or the Brits or the Japanese Notice a difference in foils?
Why?

da Rock

Well, for one major reason, the British and German fighters were all designed without any consideration for an economical cruise. They never considered escorting bombers on long missions. No thought for that at all. They were designing interceptors, not escort fighters. They didn't even have room in most of those tiny little suckers for the pilot, much less gas tanks, because the idea wasn't to do anything other than climb fast and intercept.

You know, focusing on minute details often leads one astray.

They put a "Mustang wing" on the P-40 and the sucker was awesome. Of course, at that time they also slapped a different engine in it and included a decent supercharger. "Small details"........

da Rock

Oh yeah, they also got rid of the turtle deck, changed the air intake design, moved the radiators and ran a different spinner and prop. They did chop the distinctive wing tips too. But it still had the retract bulges. And was still designated as a P-40.

topspeed

Also Spiteful wasn't a big success ( a Spit with a laminar foil ).

Eppler 201 is 30% the thickest.

Here is a thicker foil and proven outstanding in 1/12 scale air combat ( in Steve Hergett designed Mustangs ).