Mustang Wing Panel Lines...From the Preeminent Mustang Restorer's Point of View

[One-Oh-Four]

 

And another contemporary photograph of the P-51D. Also Wikipedia.

[The Dude]

1 hour ago, One-Oh-Four said:

 

And another contemporary photograph of the P-51D. Also Wikipedia.

I see panel lines on that one... I am of the belief that mustangs started off as puttied and refined but as time passes that stuff will eventually come off. Didn't a lot of crews strip off paint with gas on a semi regular basis? I would suspect the gas did not mix well with filler.  Plus if the plane lasted for quite awhile in theater with heavy use that stuff came off eventually. I would guess the crews we're more interest in turning an aircraft and made sure they got back from each mission rather then spend the time refinishing the wing as it came from the factory 6 months to a year ago.

I remember many, many years ago a luftwaffe pilot was giving a presentation on his war exploits at a local show, someone asked him what color was the wheel well and landing gear on his 190 he flew. His response was "I didn't give a crap if it was pink as long as it got me back home" 

Edited December 13, 2019 by The Dude

[BrentE]

2 hours ago, The Dude said:

I see panel lines on that one...

 

If you blow that image up, besides the chord-wise wingtip panel lines, it looks like some discoloration over the panel lines and not a butt joint.  That's the "hint" of panel lines that I referred to earlier.

 

2 hours ago, The Dude said:

I am of the belief that mustangs started off as puttied and refined

 

Not in question, all Mustang wings were factory finished as such.

 

2 hours ago, The Dude said:

Didn't a lot of crews strip off paint with gas on a semi regular basis?

  

You're probably referring to Bud Anderson's account of his crew stripping the unit-applied camouflage from Old Crow with 150 grade fuel.  There are images of OC's wing after the stripping and the wing finish is still in place, including shadows of the black 15" ID bands applied before the camouflage which confirms that the factory aluminum lacquer final coat was not removed by the fuel.

[Juggernut]

 

Interesting turn....

 

I do see those panel lines on the outboard section of the wings in those latest posts of the green nose mustangs.  The chordwise line mid-aileron is the wingtip removal point when the Mustang was crated for shipment and if the aircraft was not shipped in a crate, that panel line probably won't exist forward of the 40% chordline.  I also see the spanwise line outboard of that on Tika IV. 

 

As is the case in many disagreements, the truth lies somewhere in the middle between the viewpoints.  If we look at the wing from E2*S and the wing from Tika IV, you can see lines on Tika where none exist on E2*S.  The wingtip removal line is constant but the spanwise line, present on Tika near the outboard leading edge, is noticeably absent from E2*S.  I have no explanation but am considering that in some cases, the Mustang wing may have been stripped of its finish (for whatever reason) in spite of the importance of the need for a smooth surface for boundary layer airflow.  Not that the putty/surfacer was visible through the finished surface but that the entire finish was stripped off from at least the top of the wing (which is what my eyes see on those green nose Mustangs).   I recall Bud Anderson relating a story about how he came home from a mission with his plane in green camo on top and telling the ground crew that the first snows had fallen on the Continent.  He also related that he had put himself on the mission board for the following day.  He came out to his aircraft the next day and the thing was silver...the ground crew had washed the paint off with gasoline he said. 

 

If I expand on this a little bit with the premise that the wing was stripped of its finish (in some cases)....  Perhaps it is because of the practice of painting and removing paint that the wing finish was stripped off leaving the panel lines visible.  There are notes in the E&R manual not to use gasoline to clean surfaces with...perhaps this has something to do with that?  Is this conclusive?  No, not yet.  Why would the wing be stripped of its finish when it was so important to the boundary layer of the aircraft wing?  Did the achievement of air supremacy over the Continent reduce the need to milk every last ounce of speed from the aircraft, consequently letting the wing finish deteriorate and/or be stripped off?  Was this a theater, group, or individual aircraft practice as it's obviously not consistent from aircraft to aircraft?  So many more questions than answers now.... The area within the leading 40% chord area of the main wing (inboard of the wingtip removal point) is still noticeably vacant of panel lines which is the critical area of the wing...more questions.

 

And then there's this: 

Quote

You're probably referring to Bud Anderson's account of his crew stripping the unit-applied camouflage from Old Crow with 150 grade fuel.  There are images of OC's wing after the stripping and the wing finish is still in place, including shadows of the black 15" ID bands applied before the camouflage which confirms that the factory aluminum lacquer final coat was not removed by the fuel.

 

This is also interesting if true and blows a hole in at least one aspect of my query.

Edited December 14, 2019 by Juggernut

[BrentE]

Here's one that shows residue from the black and later white 15" band.  I have a couple more that I'll have to locate.

http://www.americanairmuseum.com/media/458

 

 

[MikeMaben]

No paint no putty ...

 

 

... purported to be a French a/c.

 

[thierry laurent]

As I wrote some pages ago there is no final and absolute 'truth' and this supported by the fact some evidences demonstrated that the wings were initially primered and puttied whereas many pictures showed that in the field panel lines were commonly visible and some wings simply show bare metal. The conclusion is quite simple, without good pictures of the plane you want to replicate, you can do whatever you want! Some people will possibly argue but nobody will be able to demonstrate you are right or wrong! 

[SB20]

Something to remember as well is a laminar flow wing is not only predicated on an extremely smooth wing surface.   Its about the shape of the wing and where the "curve" back down of the airfoil is located along the chord.  I've flown a lot of laminar flow wings that were anything but super smooth, and yet they did a perfectly fine job. Yes, smooth helps, but it's not the end all be all of making this wing what it was and is.

[John1]

4 hours ago, MikeMaben said:

No paint no putty ...

 

 

... purported to be a French a/c.

 

Is that a museum exhibit or a picture of an operational Mustang?   Doesn't mean much either way, by the Korean War it was pretty common to see F-51's with the putty gone.  Nice detail shot regardless.

[Radub]

38 minutes ago, John1 said:

Is that a museum exhibit or a picture of an operational Mustang?   Doesn't mean much either way, by the Korean War it was pretty common to see F-51's with the putty gone.  Nice detail shot regardless.

 

The P-51 D "Willit Run?" In the "downtown DC" Smithsonian has a "stripped" wing without the lacquer coating.

Radu

[rafju]

And what does this film inspire you? (at about 30mn and more)

https://www.youtube.com/watch?v=eqqrjnJFDnU

 

[mozart]

31 minutes ago, rafju said:

And what does this film inspire you? (at about 30mn and more)

https://www.youtube.com/watch?v=eqqrjnJFDnU

 

Inspired me with the shots of T-6s being built, brilliant!

[Anthony in NZ]

FWIW the RNZAF started stripping the wing  putty off due to cracking. I have seen the official records to do it and why.  The few that were re-done were to be sprayed with a hi build primer and sanded smooth.  Rather than puttied.

Post war of course and presumably having a more sedate life with the Territorial's.

 

Hope this helps the discussion as maybe it didn't last long in a tough combat environment???

 

 

 

[Radub]

Talking of antipodean Mustangs, there is a great book by David Muir called "Southern Cross Mustangs" 

https://www.redroomodels.com/product/southern-cross-mustangs/

 

In this book there are some very interesting photos of Mustangs that had a very rough paste applied to the leading edges of the wings. I do not have access to the book right now, but I will try to get some scans of these "rough wings" tomorrow. 

 

Radu

 

 

[John1]

Somewhat relevant, just got the latest issue of Flight Journal.  They have an article about a Mustang pilot and in it, a great pic of a P-51B with a protective rubber mat placed on the wing root from the leading edge to aft of the cockpit. So at least on occasion, they made an attempt to protect the wing’s surface.