P-51 NAA/NACA 45-100 airfoil graph

[greybeard]

Hi all!

I was unable to find graph showing coefficients of lift and drag as a function of angle of attack about early Mustangs (P-51A/B/C/D) airfoil. What I'm looking for it's like following graph:

extracted from NACA report No.824 "SUMMARY OF AIRFOIL DATA", dated 1945, that seemingly should include all airfoil data but misses the 45-100.

Any help?

 

[greybeard]

It's curious this lack of info about the most famous WW2 American fighter...

Thanks anyway,
GB

 

[Shinpachi]

Be patient, greybeard

When I asked about a B-29 nose art, there was no answer for half a year but several people were kindly checking to answer.

 

[hlppls45]

The Mustang airfoil was not a standard airfoil but used the basic airfoil data combined with modifications to meet specific pressure distributions along the wing panel. If you have one of the drawing cd sets, the information can be found in the wing analysis document.

 

[drgondog]

It was a NAA proprietary airfoil design modified from a NACA Laminar flow airfoil.. IIRC the pressure distribution desired then was washed through an NAA proprietary Theodorsen transformation to generate the X-Y co-ordinates.

 

[Algernon]

Gentlemen, Mustang airfoil — but only from "other side". German report from 1943. (Measured on Mustang mainplane, in 1943 — most probably from any forced-landed or belly-landed airplane.)

Text in Czech language —
scan 0001 : drag coefficient (x, or horizontal), lift coefficient (y, or vertical)
Mustang airfoil compared with NACA 2415 airfoil

scan 0002 : pressure distribution
ssací strana : suction side (or upper wing surface)
tlačná strana : lower wing surface

scan 0003, 0004 : Airfoil coordinates, scan 0004 compared with NACA 6 laminar flow airfoils (NACA 65,2—016)

More details probably in:
"Bericht Braunschweig 43/7 (1943)"
H. Doetsch "Versuche am Tragflügelprofil des North American Mustang", FB 1712/1 (1943), 1712/2
K. Bussmann "Messungen am Laminarprofil P-51 Mustang", FB 1724 (1943)
Breford Möller "Messungen am Originalflügel des Baumusters P-51 Mustang", FB 1724/2

In german (or D.V.L.) this airfoil is described (in five digits) as 1,6—50—13,6—0,825—39
1.) is 1.6 per cent maximum airfoil camber
2.) maximum camber in 50 per cent airfoil chord line
3.) maximum thickness
4.) radius (in per cent) of leading edge
5.) max. thickness is on 39 per cent of airfoil chord

 

[greybeard]

Algernon,

I apologize for the long delay, but I had lost track of this thread.

Thank you heartily: the search must have been hard and labourious!

Definitely, it looks an unique case!

It's a pity that it lacks of diagram of lift as a function of angle of attack. Indeed, there's the partial derivative of Cz as a function of alpha, but too much time has passed from when I performed an integral last time!

Thank you all for your support and additional information!

Kind regards,
GB

 

[tanze]

Hello,

I found some data on an italian article from 1947.
Italian researches were doing reverse engineering by comparing laminar airfoils from wrecks or captured aircrafts.
Attached are at least some data coming from a P51 shot down by the luftwaffe during the war.
Reynolds nr. was around 2.7*10^6

 

[Simon Thomas]

It's a pity that it lacks of diagram of lift as a function of angle of attack. Indeed, there's the partial derivative of Cz as a function of alpha, but too much time has passed from when I performed an integral last time!

I found R & M 2251 which was referenced in Algernon's post. It has a lift vs AoA curve on the last page. I'd suggest reading the whole report as it discusses the limitations of the models and wind tunnels that were used.

I know it is an old thread.


Edited to add: R&M 2222 Fig. 157

 

[thunderbird]

Caution against using 2-d section data to predict 3-d wing data, for not the least of which is spanwise thickness ratio changes, body effects. and wingtip effects, plus other geometry effects such as taper ratio, aspect ratio, wing twist. But whadoo-eye-kno about whadyoo-kno

 

[georgecayley]

Hi, I'm a warbirds enthusiast new to the forum.
I've been thoroughly reviewing many (online) sources of documentation regarding P-51 Mustang, my interest is centered in P-51's aerodynamics.
So far I could neither find the aerodynamics characteristics (cl, cd, cm charts) nor the coordinates tables for the NAA/NACA 45-100 airfoil.
A book from NASA special publications series explains in great detail the development of LAMINAR FLOW WING between NACA and North American Aviation (NAA) and includes a variety of original documents from different sources: The Wind and Beyond, Volume II (James R. Hansen editor, NASA, 2007 SP-4409, pdf version downloaded from https://history.nasa.gov/sp4409-vol2.pdf).
Chapter 4, document 4-26(d) of the mentioned book (see page 890) contains the "foundational" document regarding P-51 wing design: North American Aviation, Inc., Manufacturing Division, Engineering Department, Inglewood CA, "Aerodynamic Load Calculations for Model NA-73 Airplane," North American Report NA-5041, March 1941.
But unfortunately the book shows only EXCERPTS and a couple of low quality images of the original document (see attached).

Does anyone know this document?
The title in page 884 states "(d) Excerpts from North American Aviation, Inc.,...Report NA-5041, 3 March 1941, RA file 290, LHA, Hampton Va.". I understand RA file 290 refers to Research Authorization no. 290 "Investigation of effect of thickness and mean camber line shape on airfoil characteristics" and LHA stands for Langley Historic Archives.
Is it possible to contact NASA Langley Archives asking for a digitized version of this document?

 

[SaparotRob]

I have no idea what you said but I liked the way you said it. Welcome to the Forum.

 

[georgecayley]

I have no idea what you said but I liked the way you said it. Welcome to the Forum.

Thanks, I apologize for my english...
I know the document I've attached is useless due to low image quality, but perhaps it sparks the search for the original one within the forum.

 

[SaparotRob]

No, you misunderstood me. Your English is perfect. My grasp of the technical, not so much.

 

[georgecayley]

No, you misunderstood me. Your English is perfect. My grasp of the technical, not so much.

I'm doing my best! thanks again

 

[special ed]

Your English is better than mine.

 

[Snautzer01]

Your English is better than mine.

 

[thunderbird]

Just a quick point. Its very misleading to try to extract airplane performance from 2D wing section data. The specific problem is the flow is very three dimensional, from the wing flow mixing with the body flow at the wing root, to the affects of the propeller slipstream, to the wing flow moving towards the wingtip where it leaves as a vortex. And of course, laminar flow seen in the lab is nearly impossible to replicate in the real world. Most of the mustang's low drag numbers compared to its peers, comes from the attention paid to smoothness in manufacturing (in an attempt to obtain laminar flow!), rather than actually achieving laminar flow.

 

[Aeroweanie]

The coordinates of the P-51B and P-51D airfoils are available on the UIUC airfoil website (I put them there). You can download a copy of Xfoil from the MIT website and use it to recreate the 2D airfoil characteristics. But, as already noted, be aware that the 3D wing characteristics are a bit different. You need a 3D analysis, as shown in my avatar.

As to North American Report NA-5041, I don't have a copy of it, but will try to get it from some sources I have.

Here is a technical paper I published on the P-51 aerodynamics a many years ago.

 

[Aeroweanie]

In the image shown below, you can see that the P-51 wing airfoils vary across the span (BL is the distance from the aircraft centerline in inches).

I've also attached images of the pressure distribution calculated on a P-51D at representative flight conditions. These images show that the wing pressure distribution varies quite a bit across the span.