Oskar, when we discussed electric tail rotors back in mid-May (discussing the news that Bell was experimenting with such), you were dubious because you could not find a suitable motor for same.
What motor(s) did you use on the tail?
You're doing GREAT, thanks for providing the updates.
Brian
Brian,
When I started off designing the electric helicopter a few years ago all the calculations were based on power. I assumed a peak system power of 30kW of which about 10% (~3kW) would be used by the tail. For an electric tail helicopter that would require a 27kW main motor and 3kW tail motor.
High performance motors up to a few hundred Watts are freely available, these are commonly used for RC planes, helicopters and drones. From 20kW and up they are again freely available for all kinds of electric vehicles and flying machines. But between 1 and 20kW there is not much choice. I could not find a motor with suitable power, speed and weight specifications, thus the reason for initially using the existing tail rotor system on the Mosquito.
The first flying tests confirmed that the tail rotor was in fact using around 3kW, an electric conversion at that power level just wasn’t feasible.
It was only when I started looking at thrust (and not power) that I noticed that (on paper at least) it should be possible to achieve the required thrust using much less than 3kW. Drones with an AUW of 15kg were starting to become freely available, and that was exactly what I needed. The design of the etail on the Mosquito is based on a Tarot T960 drone, and many of the parts I used come from this drone. The T960 has 6 motors, I added a seventh (just in case) but have already found that it is possible to hover with only 4 motors. They are designed to run with either 17 or 18 inch props, to reduce the power requirements I’m running 18 and 20 inch props.
So far the electric tail is performing even better than I had envisioned. Some of the “fly by wire” aspects are quite intimidating, but we have to remember that cars and many aeroplanes have been doing this for a while already.
I’ll start a new topic on electric tail rotors, it’s quite a fascinating field.