I know we are really drifting on this thread, but I'd like to contribute just one thing regarding the glow vs electric controversy: A real WWI rotary or Mercedes or Hisso doesn't sound anything like a glo motor or an electric motor, or even like a four stroke for that matter.
If you want to hear actual recordings of WWI engines, there is a audio disc set available to purchase. It's called "Sounds Of Ghosts of The Great War". Aircraft recorded are: Fokker E.III, D.VI, D.VII, D.VIII and S.E.5a.
Available from AirCraft Records, (800) 982-7767, or
www.aircraftrecords.com. The recordings were made in about 2004, using modern, high quality audio equipment and original WWI engines. Cost of the two disc set is about $25.
I have no financial interest in the company. The disc set was given to me and I just like to listen to it.
Dick
P.S. The above link includes a 30 second sample that you can hear for the price of a couple of mouse clicks. It's a rotary doing a flyby. I don't know which rotary it is.