What is involved regulation wise adding an electric motor to a glider?

On Wednesday, February 3, 2021 at 3:54:59 PM UTC-8, 2G wrote:
On Wednesday, February 3, 2021 at 2:24:37 PM UTC-8, David Scott wrote:
On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?

I figure this has been asked but didn't find any threads on it.
Thanks to all for your responses. What I am hearing certainly doesn't scare me away from the idea, which is all it is at the moment but I have been "thinking" about this and possible solutions for years. My biggest take is to talk to those who would be signing it off to find out what they think of it.

I have been very involved in high-performance composites for many years, have been machining for 33 years now, and doing product development longer. I have my own CNC machine shop where I mostly make my own products so I am well equipped to do the design and manufacturing. I have done enough projects that took over 2000 hours to get into production that I do understand there is always way more work than expected, but this really isn't that big of a job, comparatively.

I really like the FES idea for modifying a stock glider for its simplicity. The only structural change to the glider would be to cut off the nose but the firewall would certainly reinforce it, depending on how the batteries are stored. The biggest downside is that the propeller has to be too small for efficiency.

You would also have to cut an access port in the fuselage to install & remove the batteries. This will substantially weaken the fuselage, so it will have to be reinforced in an engineered manner.

Tom

That is something I would avoid doing if at all possible. But I do understand that is where the batteries would have to be to maintain CG. If there is no way around it then a pylon mounted motor begins to look much, much better. The fun of design, there is no perfect answer, just the best set of compromises.