Hopefully this is allowed. Does anyone have experience with electric fixed wing ultralight aircraft?
I was previously working with a company building a electric PPG prototype. The company is effectively shut down and the remaining assets have new ownership. The new owner has no interest in the systems I spent years working on and will sell it for cheap.
This idea popped in my head 2 days ago, so its not fully thought out. I am thinking about attempting to build an inclosed, fixed wing ultralight designed around efficiency. The motor I would use is the same as on the sp140 except the higher rpm 40kv. Weight would be really tight and i hope to build a ~10kwh battery pack around 115lbs. I expect around a 6-8kw minimum cruise power.
Biggest concerns:
The Mad M50 motor is only good for about 10kw continuous. That doesn’t leave a good margin if I am on the upper end or higher than an 8kw cruise.
Climb rate might not be what I want with a 440lb takeoff weight. At my higher altitude, this power system will give the same thrust as a polini 202, so maybe its fine.
Weight will be tight. I would build the airframe first and build the battery back off remaining margin, but I really want 9+ kwh.
I would love pointers. This idea has only been brewing for 48 hours now, so I need someone to tell me if its a dumb idea.
I would use a motor that fits the continuous power you need for the ultralight. Such a motor is larger and heavier than the sp140 motor. The SP140 will also manage 8 kW when cruising with good cooling, but with poor efficiency. of around 80%, which means you burn around 1.7 kilowatts during level flight. If you use a motor that works in the 90% range, it makes more sense. Basically, I know from Rogallo projects that a good reserve is necessary for safe operation, as is the case with UL aircraft. With ppg you can land anywhere, with an airplane not so easy. You have a higher speed and therefore have to fight a lot more against air resistance. With the EPPG you know that in comparison to 40 km/h and 60 km/h about twice the engine power is necessary. But it is certainly no problem to build a small electric aircraft today. I think the idea is very good. Unfortunately, in many countries around the world, the rules don’t allow it or it isn’t allowed at all, so there isn’t much on the market here.
Thank you! This is what I was looking for and suspected. I’ll look into smaller/lighter ultralights with lower power consumption or I’ll use the system for a paramotor like I designed it for.
Peter’s ultralight was the one that made me think its possible. He is only using about 6kw to maintain altitude and his motor has comparable thermal and power specs to mine.
Why enclosed? You were designing for PPG so why not look at Delta Trikes. The Aeros Ant-E has been out for years now. Wieght shift trikes come with far less complexity to worry about. Wings are expensive when new but lots of used stuff on the market.
Looking at enclosed fixed wing mostly for power consumption, but also as something I can build myself and with traditional airplane controlls.
Most of the electric open tube frame ultralights near the 254 lb limit are pulling between 8 and 14kw in cruise. Peter enclosed just his frame and has a cruise less than 6kw and must be pushing 200lbs. Mikes ultralight is impressive at a similar 6kw cruise.
I’ll be using my spare X4 parts to power my Lazair series 2. I still have the original two Rotax 185’s (9.5 hp each). Although the ICE motors work well, they only produce about 90 lbs peak thrust between the pair of them. The four X4 motors will be more than capable to fly this ultralight with an increase in performance. I’m curious to see what the endurance increase would be vs. my paramotor wing.
