Fisher Flying Products Announces New Electric Propulsion Systems

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Bigshu

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Yikes, 20+ minutes of a talking head! I'll have to wait to get home from work to suffer through that!
 

BBerson

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Yes, motors have one moving part. But the stationary parts can fail. Most failures are over heating or burned coils. The magnets come loose. Just depends on how hard they are pushed, same as piston engines. Controllers and batteries often fail when pushed.
Electric will make sense when a packaged kit is offered for 30 minutes duration.
 

ToddK

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I have argued that developing electric aircraft is a complete waste of time until the battery tech allows for comparable range to gas engines. I stand by that. I don't thing that many people are going to put 900-2000 hours into building an aircraft only to hobble it with an hour of range.
 

TFF

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It’s called “ trying to stay relevant “.
It has to be the most popular question someone not in the hobby asks. Why not put out a statement. Creates a buzz.
You also hope you can align yourself with the right technology coming up to ride that wave. Beta vs VHS. You also don’t want to stay too long. VHS vs Netflix.
 

Speedboat100

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I have argued that developing electric aircraft is a complete waste of time until the battery tech allows for comparable range to gas engines. I stand by that. I don't thing that many people are going to put 900-2000 hours into building an aircraft only to hobble it with an hour of range.

Hour is a long time...paraglider with batteries last just 5-15 minutes.

Add solar power to it and you can fly all day long:
 
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TFF

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I think even if you use it, flying two hours out and two hours back makes an airplane worth to build. Pt103 UL lives a different life.
 

pictsidhe

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Electric motors can last between hours and decades. We have a 30yo 100hp BLDC that doesn't look like it has ever been opened. Bit heavy for a plane though. Seen some BLDC die in hours.
 

cluttonfred

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As BBerson said, when someone is able to offer truly complete electric power packages for homebuilt aircraft then we'll start to see real change. If we are talking conventional power aircraft, not motorgliders, then I'd say two hours endurance at a minimum. When I have looked into DIY electric vehicles of all kinds in the past, my conclusion has been "this is not as easy as it sounds."

So by "complete" I mean a motor with a redrive to bring prop RPM and diameter in line with what we would expect, one or more battery packs, a charging system, and all the electronics required for battery and motor management and protection right down to the throttle and necessary gauges. Ideally it would be in a package the right size and weight to be a drop in replacement for a Rotax 912, small Continental, or VW conversion (with additional battery packs located elsewhere in lieu of fuel) so conversion of existing designs would be very straightforward.
 

pictsidhe

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An electric package for conventional GA aircraft is simply not currently possible, or anytime soon. Battery technology is just not good enough. There may be a huge leap there, but it is unlikely. Don't hold your breath for a draggy electric plane or a 912'e'.

What is possible now are electric motorgliders, but with a limited range. These aren't radically different to fly than a GA draggy plane, so why not take the available compromise? Whining about 'needing' a drop in electric engine isn't going anywhere for many years. Do what what you can, with what you have, where you are now! Pipistrel and a few others are doing exactly that. There is no magic trick possible to electrify a 172 and not have it be crap.

The redrive for electric is pretty trivial compared to an IC redrive. Motors and drive electronics are already available from ground EVs. Batteries need care. Poor engineering there can easily mean fire.

Electric has some advantages that can be used in design. But you have to either design around electric, or be quite picky about what you try to convert.
 
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rv7charlie

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A gentle reminder about the 'practical', '2-4 hr endurance' etc complaints. Go back and look at the subject a/c in the video, linked in the original post.
 

12notes

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It all comes down to mission. Battery density isn't enough for GA right now, and is unlikely to be for 20 years. However, there are niche applications that a sub-hour of flight time would work. Short haul flights and training are two.

One that hasn't been explored is a dedicated aerobatics plane - one of the type that most pilots are personally done flying when the hour is up. It wouldn't be ideal, obviously, as it would be heavier than it's gasoline equivalent, but it would be an application that is practical now. It would also allow maneuvers that are currently impossible, for instance, if you had a prop that could be adjusted 180 degrees and had a sufficiently powerful reversible motor, you could stop the plane in the air nose down. It would probably be able to do several new types of spin. Just having the option to completely stop and restart a fixed prop whenever you wanted would add options. Someone more experienced than I would probably be better for imagining what's possible with it.

That would be my target if I were designing an electric plane now.
 

Cy V

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An electric package for conventional GA aircraft is simply not currently possible, or anytime soon.
Someone forgot to tell that to Pipistrel and they developed one...

 

BBerson

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Most electric ultralights are using salvaged Zero motorcycle wrecks. Complete kit except the belt drive.
Not ideal dealing with salvage, but it works.
 

12notes

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Someone forgot to tell that to Pipistrel and they developed one...

From your article:
"Because the plane can only cover around 100 km (62 mi) per flight, the team will need to perform six stops along the way. "

It's a 435 mile flight that will take them 2 days. This is not practical for GA. This is a publicity stunt in a specialty plane with a niche application - not a practical plane for GA use.
 

ToddK

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The electric Pipistrel is a toy. A novelty with no real value. They might sell a few to people with more money the brains.
 
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pictsidhe

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Someone forgot to tell that to Pipistrel and they developed one...

Ummm, no, they did not 'forget'. 30hp-h is not going to replace a GA engine. Especially once you look at the weight of it. Just the batteries are over 300lb. Total weight is going to cost the passenger in a conventional VW design.
Look closer at the Pipistrels. Much bigger span than GA of similar gross. They had to adapt their aircraft to suit electric. They most certainly did not make an electric power pack and slap it into a conventional GA design.
 

12notes

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Texas Aircraft just announced today that they are developing a new electric airplane with a two hour endurance.

Texas Aircraft Electric Airplane
"The aircraft will be designed ..."
"OXIS projects that the eColt will have an endurance in excess of two hours and an approximate range of 200nm. "

This isn't a plane, nor is it even a design yet, it's just a thought and some paperwork. When they actually produce the plane, then it is significant. However, the numbers don't add up here.

The Colt they plan on modifying has an empty useful load of 469 lbs, and an engine weight of 125 lbs. If we add another 25 lbs for engine accessories and round up to get 625 lbs for total weight available for the electric conversion. Lets say that we want the same useful load as a full tank of fuel in the Colt, 275 lbs. This leaves you 350 lbs for electric motor and battery. Let's assume the electric motor, controller, and all wiring are completely weightless. This leaves all 350 lbs (159 kg) for the battery.

The gasoline Colt cruises at 75% power on a 100 hp engine, 75 hp = 56 kW. Texas is claiming the electric version has an endurance of two hours on a 90kWh battery, so 45kW = 60hp (60% throttle of the gasoline) . The battery would have to have a density of 90000Wh/159kg = 566 Wh/kg. Oxis, the manufacturer of the battery, states on it's website that for its individual battery pouches: "500Wh/kg targeted for 2020". Assuming they hit this goal, the 90kWh battery would weigh 180kg (396lbs), leaving a useful load of 229 lbs. Or, if you prefer to keep the 275lb useful load, 79.5 kWh, or 1 hour and 45 minutes of flight time with no reserve. They would need not only Oxis to reach their goal, but to exceed it by 13%. This is asking a lot.

What I have done is an unrealisically optimistic estimate in favor of the electric plane - the motor, controller, and wiring are not weightless, takeoff and climb use up more of the battery than cruise, a reserve is required, more than a 275 lb useful load for a 2 seater is desired, the battery density is a goal not a reality, and the battery pouch weight does not include packaging, wiring, and cooling. The numbers don't hold up on this one. When you add the rest of the weight and factor in the climb, the pilot would need to be well under 100 lbs and the plane would need to be pushed off a very high cliff into descending terrain towards a well placed airfield to have an endurance of 2 hours with zero ability to do a go around.

By the time all is said and done, it might realistically have a endurance of 1 hour 20 minutes, which is a big improvement, but nowhere near what they claim.
 
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