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Fisher Flying Products Announces New Electric Propulsion Systems

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Bigshu

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Can you cite some study or survey that quantifies a "tremendous pent up demand ..."

Thanks,

BJC
I don't have a study handy, but Dan Johnson talked about the FAA realizing their mistake in excluding electric from the original LSA rule. Dan's interviews with the electric community shape my views on where builder interest is. He wouldn't keep interviewing them if there wasn't viewer demand...
 

Bigshu

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There is a big difference in widespread interest and actual demand from people ready to spend the money.


BJC
Yeah, I get caught up in anecdotal evidence. Still when you see free, or super cheep recharging stations at the grocery store and Wal Mart, it seems like there's already more people driving electric than you might think. All I know is that when I go to Airventure, electric anything draws a crowd.
 

EugeneBDaniel

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Unless somebody starts sinking trillions of dollars into battery tech, long range ecraft are not going to happen soon. EV manufacturers are already making a huge investment.

What I keep seeing with electrical experimenters is not them being unable to obtain reasonable performance electrical stuff, it their attempted use of it in draggy airframes and expecting decent performance.

Wrong, wrong, wrong. This cannot produce anything but mediocre results. It's physics, Jim!

If you want an ecraft, you need to stop looking for a power system that will not be available for decades. Instead, you need to build a low drag airframe that will make the best use of technology that is available now. The motor and batteries are NOT the stumbling block. It's the expectation that current tech can power draggy airframes.

The AR-5 has one of the lowest flat plate drag areas ever measured. 0.88 sqft. It was also built in an old restaurant, instead of a mega buck NASA facility. Seems like a good starting point to me. Educated guesses follow:
We aren't going to build something that can fly at 200mph for long. If we drop to 100, we have about 1/3 the drag after increasing the span and wing area to deal with lower speed. We can go 3 times further for 6 times as long. Perhaps 10-12hp needed for level 100mph flight. A pair of Tesla model S 60lb battery modules would keep us flying for around an hour. Less once you add reserves. Going up to 4 packs may be a good solution. 2 in the nose for balance, 2 in the wings. 100mph and 150miles with reserve seems worth doing to me. It could fly a lot faster for short periods of fun.
An example of what is possible with low drag, low speed, & increased wing span is Greg Cole’s Electric GosHawk Windward Performance or in pdf:
 

BJC

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12notes

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An example of what is possible with low drag, low speed, & increased wing span is Greg Cole’s Electric GosHawk Windward Performance or in pdf:
Since there are no actual pictures of the GosHawk with landing gear on it, it doesn't seem like they're done building the first one.

Also, their performance chart states the battery is 11.4 kWh, but the numbers in the energy used column add up to 12.1 kWh - 2.5kWh climb, 7.5kWh cruise, 2.1kWh reserve. It's not promising when they get simple math wrong.

Correcting the chart to the actual battery size gives a cruise energy used of 6.8kWh, reducing cruise time to 1.36 hours and a cruise range of 99nm, which is about what electric planes are limited to at the moment. The 51 foot wingspan rules out a standard hangar, unless one wants to install and remove the wing tips every flight.
 

kennyrayandersen

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Motor gliders might work with a 15-20 self-launch. Batteries are still WAY too heavy. I'm thinking carbon dragon with an up-scaled wing, and battery pack like the Archaeopteryx; 10-15 minutes to launch and 5 minutes reserve. The battery pack, motor, and hardware are around 50lb.
 
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