What's this plastic plotting tool?

[MadamBreakneck]

Originally Posted by golfbananajam

looks very similar to this

https://www.google.com/search?rlz=1C1GCEA_enGB807GB807&q=artillery+trajectory+chart &tbm=isch&source=univ&sa=X&ved=2ahUKEwjnvvSE3YviAhWRo3EKHf4E Do4QsAR6BAgGEAE&biw=1920&bih=1095#imgrc=nb6GX3hY6BGKqM:

or many other similar examples (all paper based) I can find on Google

Would it be the same calculations for air-launched ordnance?

That link shows similar curves so I'd guess that's what it is, and no wonder I didn't cover it in my PPL studies ;-)
It would be of passing interest to know what the scales meant and how it was used, if anybody knows. Otherwise I'll take it that it's some sort of ballistics calculator that's got mixed up in a display of air navigation bits.

Dook, many thanks for trying photoshop.

thanks all
MB