Archer wrote:
I think that the nationality markings may be required when flying on a military registration. So perhaps it was needed for test flights, before application of the final colourscheme.
In all if the photos I've seen of U.S. aircraft, they were painted before test flying.
To use a fairly famous photo...
https://commons.m.wikimedia.org/wiki/Fi ... _Texas.jpgSome assemblies were painted before being fitted to an airframe.
As far as a regulation about national markings having to be on aircraft before test work, I have my doubts. There are instances in the war of aircraft without military serial or CAA "N" number flying.
Generally, I figure everyone was to busy to worry too much about some admin rules.