Proving 51% Amateur Built

[Sonerai13]

And it doesn't even have to be just "you". There can be any number of builders as long as they are all building for "education and recreation". You can buy a project started by someone else and you're still legal for the 51% rule.

Very true! The only caveat there is that there had better be good builder documentation from the previous builders to verify that they were amateur builders as well as yourself. A very important thing to look for when considering the purchase of a partially completed project.

[Sonerai13]

The manufacturer is generally, almost always, the person who built the plane. Model/Serial number can be anything you want it to be....for example "Joe Smith Sonex SN 001".

Yes, for an amateur-built aircraft, the manufacturer will be the person or entity who actually built the aircraft, not the kit manufacturer. This can be (and usually is) a person's name. But it can also be a corporation or LLC name if the aircraft is registered in this fashion.

As for serial number, it is recommended that the builder use the plans or kit serial number, but it is not required. The only requirement is that the serial number be unique within that manufacturer name.

[Area 51%]

That works. Or you can use AeroVee for make, 2.1 for model (or 2180), and the serial number off the accessory plate. Easy Peasy![/quote]

Since the form asks for manufacturer (not make) I didn't consider using AeroVee in that location on the form. Because my engine is a hybrid with limited AeroVee components, I'm not sure it would be appropriate to use the name AeroVee anywhere on the form. I do have the mounting plate with the serial number and AeroVee logo though.

[Sonerai13]

That works. Or you can use AeroVee for make, 2.1 for model (or 2180), and the serial number off the accessory plate. Easy Peasy!

Since the form asks for manufacturer (not make) I didn't consider using AeroVee in that location on the form. Because my engine is a hybrid with limited AeroVee components, I'm not sure it would be appropriate to use the name AeroVee anywhere on the form. I do have the mounting plate with the serial number and AeroVee logo though.

On all the FAA forms used for amateur-built certification the FAA uses "builder", "manufacturer", and "make" pretty indiscriminately. For the purposes of amateur-built certification they all mean pretty much the same thing. You just need to stay consistent once you choose something.

For your particular situation, where the engine is a "one-off" you could call it anything you want. Use your name, just like on the airplane, or make up a name. It could be the "Belchfire 2180" or whatever you choose!