The yellow was standard naval aviation color for a trainer plane. It was simply a conspicuous marking of a beginning pilot, to warn other pilots and ground crew not to necessarily expect normal or competent behavior!

Trainers were often referred to as "Yellow Perils." Tighten your seatbelt and helmet straps!

Those were the helicopters of their day. And that must have been one of the most scary piloting jobs ever.

Landing an aircaft without propulsion, under enemy fire, in the dark, on unknwon (and next to invisible) terrain - sounds like a crash to everybody else. No second guesses (a.k.a. go-around), either. The US glider pilots had a "G" on their wings. And rightfully claimed "G is for guts".

There are two very good accounts, one by a Gerard M. Devlin (Silent Wings), and one by John L. Lowden (Silent Wings at War).

And the crazy things they did with medevac and bungees.

But all things considered recreational glider flying is much preferable.

The yellow in this case is not zinc chromate primer. It's conventional yellow butyrate airplane dope. Zinc Chromate was used in some applications over aluminum to make the paint stick better by chemically interacting with the oxide layer that forms over bare aluminum. Dope doesn't stick to any non-porous material very well (except itself), so this was necessary to have it stick. It also reduces corrosion when exposed to salt water (which is relevant because the planes were delivered by ship - and corrosion damaged entire manufacturing runs of various airplanes). It's not a pure yellow, it's more greenish (as shown in the B-25 pictures).

This airplane had some area of aluminum, but a lot of it was covered with fabric (linen, probably) that needed to be painted with something to seal it up, hence, airplane dope. It would seal the material against moisture, and also shrink and draw the covering tight. Why they chose yellow, I don't know, but the standard paint scheme at the time was yellow and a medium-light blue. That is the yellow here, it's a Federal Standard paint color.

Apparently that shade of yellow was very popular with the wartime suppliers. I have seen it multiple times on planes, jigs, and plant equipment. Wonder if there was some reason it was so widely used.

[It's a primer coat. -tterrace]

I love these Kodachromes! Please keep 'em coming. Great stuff.

Fairly sure this is an N3N primary trainer. Like many US biplanes from the interwar period, they were an attractive little machine.