Weight of a/c paint?

[Stephan Wilkinson]

Probably a questions best answered by somebody who has actually painted a warbird.

I'm writing an article on the history of camouflage for Military History magazine and am wondering what the actual weight of the camo paint on, say a P-51-size aircraft and a B-17-size aircraft was. (It would of course be something less than simply the weight of a gallon of paint times the number of gallons required, since all the solvents would evaporate away, if that can be calculated; probably the only way to do that would be to weigh the airplane immediately before painting and again afterward.)

Would it have been enough to make any difference in the aircraft's performance? Probably not, which would lead me to assume that the USAAF stopped camouflaging its WWII airplanes when they had complete air superiority and camo no longer was needed, and painting an airplane was just another bit of work and expense that had no real point. (Except for Navy aircraft, corrosion protection probably wasn't a consideration on airplanes that weren't intended to last that long anyway.)

Any thoughts?

[b29driver]

Found some info on the interwebs that indicated that a 737-200's paint weighed about 450#.

[Cvairwerks]

Stephan: Paint weight can be a significant factor in performance. From what I can remember on the C-5, the weight is over a ton. When you combine the paint iteself and any aerodynamic filler used on panel seams and gaps, it goes up even more. It's a multi-edged problem with paint on aircraft....the paint helps make the aircraft last longer in certain enviroments, but it can complicate maintenance and hide problems. It also eats into your load capabilty but at the same time it can help tip survivability to better numbers for the flight crew.

With powered control systems, keeping the weights down is not as important as straight mechanical controls. Straight systems do need to have control surfaces balanced after any work, including paint, to keep them within the requirements for flutter, where FBW and powered systems do not.

I would suspect that the deletion of paint from US aircraft later in the war was not only because of having air superiority, but also from trying to maximize loads and ranges for the various aircraft. I would also belive that it was also fairly well known at that point about the typical lifespan of the various aircraft and that they would generally survive to that point independant of paint or no paint. Additionally, deletion of paint was also a huge time saver in both production and maintenance. If you can shave a few hundred manhours off production of an aircraft and save a corresponding amount on maintenace, it was going to be done.

BTW... Several of the latest generation aircraft have very specific coating requirements as the coatings are critical to the operation of the a/c.

[RickH]

Don't forget the primer that is under the paint. It probably weighs more than the paint due to a higher solid content. The military also specs a high solids paint which is probably a little heavier than something like Jet Glo. Of course it also depends how many mils thick the primer and paint is laid on.

[The Inspector]

Found some info on the interwebs that indicated that a 737-200's paint weighed about 450#.

And that same 737 in service will put on about a pound a day in accumulated 'stuff' dropped or spilled by the passengers.

[bdk]

Not to mention moisture picked up in the wing fairings.

[mike furline]

I don't know what paint ways, but I do know that Violet is the heaviest color and Red is the lightest.


edit: weighs -oops

Last edited by mike furline on Fri Sep 21, 2012 12:50 pm, edited 1 time in total.

[The Inspector]

I don't know what paint ways, but I do know that Violet is the heaviest color and Red is the lightest.

On average, around 10.25 lb/gal+1 qt of hardner +/- @ 2 or so lbs right @ 13 lbs

[mike furline]

I don't know what paint ways, but I do know that Violet is the heaviest color and Red is the lightest.

On average, around 10.25 lb/gal+1 qt of hardner +/- @ 2 or so lbs right @ 13 lbs

Which color?

[shrike]

Taigh just repainted his Harpoon, so he would have current numbers, at least for paint usage. You'd still have to estimate the VOC content for the solids and binders that actually become part of the airplane.

I would opine that the big savings came in production time, rather than weight. If you think of the prep time, paint time, drying time and extra space required for priming and final color, wages for the guys (and gals) that taped, wiped , spayed and moved the bits, and of course the paint itself, the savings are phenomenal.
Where there was a tactical need, NMF aircraft could be painted in the field, but stripping one was much less common. I doubt the weight savings on something like a B-17 or B-24 would exceed the variation in crew weights from one ship or mission to another.

[51fixer]

Probably a questions best answered by somebody who has actually painted a warbird.

I'm writing an article on the history of camouflage for Military History magazine and am wondering what the actual weight of the camo paint on, say a P-51-size aircraft and a B-17-size aircraft was. (It would of course be something less than simply the weight of a gallon of paint times the number of gallons required, since all the solvents would evaporate away, if that can be calculated; probably the only way to do that would be to weigh the airplane immediately before painting and again afterward.)

Would it have been enough to make any difference in the aircraft's performance? Probably not, which would lead me to assume that the USAAF stopped camouflaging its WWII airplanes when they had complete air superiority and camo no longer was needed, and painting an airplane was just another bit of work and expense that had no real point. (Except for Navy aircraft, corrosion protection probably wasn't a consideration on airplanes that weren't intended to last that long anyway.)

Any thoughts?

There were a couple areas of paint that changed with time.
Though the war Alum internal parts were protected with Zinc Chromate Primer. Often some parts were anodized as well.
To save time and costs Alum parts made from Alclad, which was a thin layer of pure alum rolled onto the top and bottom the stronger alum alloy base in large sheets, were left un-primered. Often where holes were punched and the edges might have Zinc Chromate paint brushed on to those edges that expose the alloy.
This was done more to save time but could also save some weight.
Late in the war some returned to the primer as corrosion became a concern and I think they realized they had the upper hand on production.

On the P-51 they added a filler to smooth the wing so even after they dropped the camo they still painted at least part of the wing to cover the filler material.

Todays paint are formulated quite a bit different than back in the day. Many top coats are chemically activated rather than just a compound that the solvent evaporates out of. The same square footage covered in paint now compared to WWII would be heavier.

[JohnB]

Stephen....
Another point about camouflage...though not about weight:
In his chapter about BOAC Mosquitos on the UK - Sweden run during WWII, Ernest K. Gann mentions in his Flying Circus book that a Mossie with "lamp black" finish was 26 MPH slower than one with the standard paint.

Ceratily the standard RAF was not glossy by any means, but to knock off so much speed, this finish would have to be very rough.

[Stephan Wilkinson]

Funny...I bought that chapter (and a number of others) to run in Flying Magazine when I was the executive editor..."The Ball-Bearing Run," I think we titled it, and I remember how contemptuous of Swedish "neutrality" Ernie was.

[RandolphB]

Weight probably figures strongly into things. In the 70's, my next door neighbor was Head of Mait. for Eastern Airlines in Central Florida. He talked about the new paint scheme they were introducing as a huge weight savings that allowed more cargo/ fuel to be carried. Eastern used to have painted aircraft with colored stripes on the side. They went to polished aircraft with only painted stripes....

[51fixer]

I have some copies of NAA newsletters covering the P-51. I'll check if they mention anything specific to the difference when they stopped the external painting.
There is also a paint shop next door and I'll ask if they have any numbers on paint weight per square foot of coverage. If you know how much square footage on an aircraft and how much paint weighs per square foot you could come up with some reasonable numbers.