Details on the effort:
Electric Paramotor Efforts
Neil Andrews is a Mechanical Engineer with significant experience applying electric locomotion. He has been flying mostly ultralight-type craft, including paramotor, for about 15 years. His first draw to paramotor was as a means to a soaring end. But the fun of low and level was not lost, either. So he set out to combine his talents and build an electric. His creation is a work in progress and he hopes to work with a team of compatriots to market an electric machine by May, 2008.
12/19/2007 Neil shared his ambitious ePPG plans today.
He's having a 2nd frame built with plans to have 12 built and flown by experienced pilots by the end of February 2008. Presumably these will be sold under cost to get input for the first production model although these, along with most specifics, aren't finalized.
The machine has had 3 flights and 5 hours of ground run time.
The current machine, as shown on the video, is described as follows. The test flight was done under an Airwave Sport Medium with the pilot weighing 70 Kg on a day with temperature probably about 40°F. The electric drivetrain was mounted on a Pap 1100 machine. Power is described as being about that of a Top 80 although the prop is slowed intentionally down a bit from that of a typical Top 80/geardrive.
Batteries: Lithium Polymer (LiPo) with a 20 A h (ampere-hour) capacity. Cost of this much capacity is about $1600 with a 300 cycle life down to 90%. That means that, after 300 cycles, you'll get 90% of the run time as when new.
Motor: 2 off-the-shelf Brushless DC motors spinning the prop through a belt. He's considering gears for efficiency. Two smaller motors are a lot cheaper than 1 large motor and dissipate heat better although he's considering having just one motor.
Prop: 99cm (39 inch). He says an immediate 25% increase in flight time is likely with a 1.25 meter (49 inch) prop and is working with Helix props to find the most effective solution there. Obviously that would increase power efficiency at the expense of increased drag from a huge cage.
Controller: Infinitely variable. Response is said to be smooth and very quick with fine increments. Power fall-off still leaves gradual throttle through the decreasing max thrust as batteries die out. The controller shuts it down before batteries are drained too low which would damage them.
Fire protection: Did not ask about on the motor but the few problems that befall LiPo batteries usually involve overcharging. He said that basic precautions should be taken but fire are extremely rare.
Charging: Currently 4 hours from either a car or wall outlet. Neil has ordered the charger that will allow 1 hour recharging. Note that in England, wall outlets are 240v with a 13 amp capacity. That is nearly twice the capacity of U.S. outlets.
Safety: He recognizes the particular risk in having a motor that sits so silently, innocently ready for full power. He's working on solutions to prevent accidental engagement.
Duration: 20 minute flights on these batteries (1600 watt-hour) are doable now with the right prop. He's flown 16 minutes. He plans to equip it with enough batteries for 30 minute flights.
Pilots must either fly it more efficiently or be willing to sacrifice flight time. For example, if you're judicious in power use, 30 minutes is quite doable. If you'll be yanking and banking and using lots of thrust, flights will be more like 12 minutes. Neither is right or wrong, these are simply the trade-offs.
Price: Developing these things is expensive but he hopes to keep it under US$7000. That obviously depends a lot on exchange rate and finally developed parts cost.
|We don't have any pictures of this unit yet but will hopefully get some soon. See the video for now.|
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