New member with a question

[tsb]

Good afternoon - I am a new member, but have been lurking here on and off for some time.

I have been collecting HP calculators for about 5 years and recently came across a 41CV that was modified by Sikorsky Aircraft as a weight, balance, and performance calculator for the CH-53E helicopter used by the US Navy. It has two custom ROM modules, a custom bezel in place of the standard HP, some black painted over keys, and a Sikorsky rear label. The label indicating the model is blank and it does not appear that one was ever installed. I have found reference to this unit being developed, but can't find any other information. Has anyone ever seen this before?