Half painted Fw 190 wing undersides - the purpose?

[Crumpp]

No, it was only to speed up production.

Actually according to sources at the USAF Museum at Wright Patterson it was due to performance. This is also backed up by the experience we have in using original finishes.

The paints used by the USAAF in WWII were all contracted from the same company out of California. Proper application took at least one coat of primer, 2-3 coats of paint, and clear coat. This adds almost 200 lbs to the weight of a P51D fighter. Using the original paints, in just 2 hours in the air, the paint begins to crack and chip. Faster if the aircraft is maneuvered hard. This adds drag and degrades performance. Both shedding weight and reducing drag improve an aircraft.

These T6 Texans are painted with WWII USAAF paints and the B17 had the late war USAAF finish:

http://theotherorlando.com/contents/...ingtigers.html

http://www.warbirdmuseum.com/

Now the RLM finishes are slightly different. The granulation is much smaller than what was produced in the US. In fact, the finishes seen on modern USAF fighters are a direct descendant of the RLM paints according to the USAF Museum at Wright Patterson, AFB Ohio.

This can be seen immediately on any actual RLM finish.

These drop tanks and many of our skins still have original RLM paints applied:

http://www.white1foundation.org/parts/droptank.jpg

Here is a close up of an original leading edge:

http://www.white1foundation.org/parts/leadingedge2.jpg

Our pilots chair has a new coat of original RLM paint:

http://www.white1foundation.org/parts/pilotseat2.jpg

If you look closely you will see paint is not "chipped" but rather worn. This is typical of the RLM finishes we find. The paint is chalky and while it does wear the edges tend to feather or smooth as opposed to being as thick and sharp as the US paints. The RLM finishes cover in one coat as well. When mixed correctly there is no tendency to fisheye, orange peel, or run. One coat of primer, one coat of paint, and one of sealer is all that is normally required. This means the finish is lighter. About 60 lbs for a Bf-109 on average. Much less surface area and paint which weighs less than what goes onto a P51.

I tend to think the Germans did not go to bare metal completely because with their finish technology it was not the problem it was for the allies.

Not painting the leading edge would improve performance, save production materials, and time.

So this is correct for the RLM finishes:

This was because of specifics of new camouflage coat, extremally thin. Puttied, painted and polished aircraft will always have better aerodynamics rather than the bare metal one.

But I do not think it is applicable for all aircraft finishes for all combatants during WWII.

All the best,

Crumpp