Odd Question: What can be N-numbered?

[FlyingRon]

Using unconventional/uncertified instances of instruments is what experimental is all about. That's not the same as not having any airspeed, altitude information presented.

[Ron Blum]

Using unconventional/uncertified instances of instruments is what experimental is all about.

I learned at Sun-N-Fun that our friends to the north (TCCA - Canada) have an "owner maintenance" category for previously certificated airplanes that are more than 30 years old with no manufacturer support. The example was the presenter's Stinson 108. He has replaced all of the instruments with Arduino-based, digital units. Awesome!!!

PS. Yes, the airplane airworthiness in the certified category is no longer valid.

[Frank Giger]

Using unconventional/uncertified instances of instruments is what experimental is all about. That's not the same as not having any airspeed, altitude information presented.

Meh. They're "nice to have" but hardly required for flight. I flew without an ASI for about a year with no ill effect.