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Electric powerplant on RV?

Maybe just my flawed memory, but it seems that when electric motors came to model rc planes, there were a lot of attempts to fit them to existing designs. However, the existing designs were built around heavy, vibrating engines and the need to protect against oil exhaust and fuel proofing. A brand new plane designed specifically around electric power might be the key?
 
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Sonex has been working on this for about 15 years.

Actually, Sonex worked on it close to ten years ago, flew it, then put it in the corner of the hangar, where it has sat ever since. John M. Got more interested in turbine power after that....

There is an individual who put together (And has flown!) an electric Sonex recently.

Paul
 
Electric cars didn't take off until they started building them with the intent of electric operation from the ground up. Nissan, Tesla, etc. One may argue that the hybrid started the revolution (Toyota) by giving an electric powered car to people who were afraid of giving up the gas engine.

The first purpose built electric, the Pipestrel VirusE, looks similar as they've shoehorned the electrics into an existing airframe... but the range is quite limited. I suspect any attempt to do the same with an RV would have the same result.

In the simplest conversion, one would need to replace the fuel tanks with batteries, and in the engine compartment install a new engine mount with the electric engine at the front and *more* batteries behind it. I haven't done even a back-of-the-envelope calculation on the results, but my gut feeling is that you'd lose half the range of an equivalent gas-powered RV, and you may add 5-10% to the empty weight.

If the goal is to minimize your environmental impact by going electric, and are willing to give up a little performance to get there, then it's definitely do-able and worth it.
 
I just started building the wings on my RV-8, and at the pace I’m going I probably won’t be flying for 10 more years. While I will build and seal the wing fuel tanks, I am keeping a close eye on electric aircraft and battery technology in the hopes that in 10 years it will be feasible to fly 2+ hours in an electric RV. To see how quickly the automotive industry is transitioning to electric power gives me hope that aviation will be able to take advantage of the lower costs of mass produced batteries and motors.

My motivation is not environmental or political, but primarily economic - I still can’t swallow the concept of paying $30k for a new Lycoming and $5/gal for a fuel which will only go up in price and get harder to find.

There are also major side benefits of electric powered aircraft compared to internal combustion engines — smoother, quieter, less maintenance, simpler, and of course no emissions. What’s not to like?

If other RV builders are seriously interested in pursuing this propulsion technology, let’s start a new section in this forum to share ideas and experiences.
 
Motor

Just saw that Yamaha is testing a 150Kw motor...that’s 200hp...

Of course you would need adequate battery capacity...
 
Technology is coming along

Hey all,
This is a really interesting post. Two companies come to mind on the electric powerplant front.

The first is Pipistrel, it now has a certified version of the E-811. It is the basis for their Alpha Electro, which is now flying. This is a small engine, 50 lbs, 77 hp for a minute, and 67 hp continuous. Too small for an RV it seems like. They sell an entire powertrain, including battery packs, for this system. I have no idea how much it costs.

At the other end of the spectrum is Magnix. Their "little" engine is the Magni250, which provides 375 shp continuous. They do have the inverter system developed as well. Last year when I talked with them, they were not interested in selling to the experimental market. They are pushing the "bigger" engine, the Magni 500 which is 750 shp continuous.

The Magni 250 engine is flying, Magni is working with a flightseeing company in Seattle that wants to electrify their Beaver aircraft. They and Magni have one of the Beavers flying and are working on getting it certified. This use case actually may make sense. None of the flightseeing flights are long, but the run multiple flights a day. Additionally, it turns out they put the Magni 500 into a Cessna Electric Caravan. Again, apparently Magni thinks there is a busness case for "ultra short flying."

All of the hard parts of this are the batteries and cooling. I imagine it will be a couple of years before this gets sorted out. If you could manage to buy one of the powertrains, it might be a fun project to take an older RV, rip out the engine, and replace it.

Anyway, I think this is a technology worth keeping track of!

Blue skies

Geoff
 
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This one makes a whole lot of sense.

It does???

Range 25 miles.

Recharge time 5.5 to 7.4 hours for the most commonly found electrical source.

A hundred mile flight thus equates to 4 flight legs, with a minimum of 22 hours charging time to make the flight.

At the 62 mph listed, that is slightly over 1.5 hours flight time, 22 hours charging time. Toss in 10 minutes each charging session just to get hooked up , unhooked and misc.

So, your 100 mile flight has taken 24 hours to accomplish.

Sorry, this doesn't make much sense to me.

Yes, it is interesting tech, and a fun looking craft with an interesting flight capibility.

IMHO for electric flight to get to be more than just a novelty, you need to be close to the performance of gas powered aircraft in; load carrying ability, range, speed, refueling (charging) time and cost.

Dont get me wrong, I am not against electric flight, I am just trying to see the total picture and ignore the koolaid. I look forward to the time I can plug in my plane at night and then go fly out for an hour or two, at 150 mph. Then turn around and fly home and land with the same reserves my gas powered plane has. Plug it in again and be ready for the next flight tomorrow

Maybe someday.........
 
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The electric Beaver is a collaboration between Harbour Air of Vancouver and Magnix who supplied the motor, power controls and did the systems integration. I attended the EAA webinar back in July (during Airventure) presented by Magnix and it was very interesting. Unfortunately I couldn't find it in the webinar archives. The stated goal was to electrify a Beaver for future scheduled local flights and prove (or disprove) the viability of the concept. Harbour Air and Magnix were very secretive about the payload remaining after the batteries were installed, but I heard a rumor that it was just the pilot.

I haven't heard any more from Harbour Air or Magnix after the test flight, but I believe the viability depends on another step change in the battery power/weight ratio.

All battery powered vehicles suffer from poor payload and/or poor range. Although battery technology is progressing with lots of research and development in many countries, I think the power density has to increase by a factor of 3 or 4 to be viable in an airplane.

Having said that, I think an electric motor is the perfect powerplant for an airplane: relatively light weight, low vibration, no altitude de-rating, no poisonous exhaust, etc. But when you add the weight of the batteries, inverters and power controls, well...we're still years away.
 
The RV-12 seems like an excellent candidate for this sort of experiment. But it would be just that (an experiment) as battery technology is still a ways from getting us the all around utility that most of us are looking for.

It sure would be fun to try however, just imagine replacing that big expensive heavy collection of complicated parts barely containing a carefully timed series of explosions, with something that has the same number of parts as your alternator.

I wish I had the money & extra engineering know-how to play with it. I expect someone will. No, it wouldn't go very far - yet. But with improvements in battery technology, you'd be able to drop in (ish) better batteries as they come along and perhaps even get comparable utility some day with only minor modifications along the way.
 
Electricity

I think there's no doubt that the battery density improvement trends will continue. It's almost already at the point where it makes sense to have electric training aircraft. Very powerful electric motors are already available.

I've read that the primary driver behind the battery technology improvements are the guys making electric screwdrivers. I'd have thought it was the car guys, but apparently we buy a lot more total electric screwdriver batteries than electric car batteries.
 
There are some very interesting innovations happening on the electric battery front now, but none of them promise (yet) to achieve energy densities on a par with liquid fuels.

In reality, an electric battery will need to achieve slightly better energy density than liquid fuels, as they do not benefit from the increased performance due to loss of mass in flight that liquid fuels offer.

I'll be happy to convert to electric propulsion when it offers me *an advantage* over liquid fuels. And that includes the environmental effects of manufacturing and disposing of the batteries. Until then, internal combustion with liquid fuels is the technical winner.

I don't discourage people from experimenting and developing better electric energy storage options, but as a consumer, I'll not be an early adopter.
 
I can see a hybrid system working.

2 power plants for takeoff, 1 for cruise.

Depending on mission, I'm not sure which power plant would be better for cruise.
 
I can see a hybrid system working.

2 power plants for takeoff, 1 for cruise.

Depending on mission, I'm not sure which power plant would be better for cruise.
Similar to hybrid cars, I'd expect that the gas engine would be for cruise (and recharging batteries). That way, you can size and tune the engine for maximum efficiency at cruise, and the required battery pack could be greatly shrunk to only the size needed for takeoff.

My question is: what would the actual gains be? If you fly with a 160HP 320 and cruise at 75%, you could maybe replace it with a Rotax 914 or an 0-235, which would free up maybe 100 lbs. Once you subtract the weight of the electric motor, you don't have a whole lot of weight allowance left for batteries.
 
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Maybe just my flawed memory, but it seems that when electric motors came to model rc planes, there were a lot of attempts to fit them to existing designs. However, the existing designs were built around heavy, vibrating engines and the need to protect against oil exhaust and fuel proofing. A brand new plane designed specifically around electric power might be the key?

Having been in an engineering research org for a few years, this is the 99% case. This is why the Prius design is much more value added than nearly all other hybrids. Cars work because of energy lost to various things, braking being the most significant, then allowing the gasoline power plant to operate much more efficiently w/o operation compromises or not operating at all.

Electric motors require amps, amps yield torque, amps require copper, copper is heavy. PM motors of certain configuration can operate quite efficiently at high rpm, without the friction losses like a recip engine. I dont understand all these direct drives?? It would be a lot more weight efficient to use a low amp, high voltage (400-600), high speed motors with an efficient gear box. Another development of it's own.

A test platform for learning is fine, but the component technical objectives and technology roadmaps seem to be missing in aviation. The US government research program managers do a pretty darn good job of driving these roadmaps.
 
Question: is a propellor more efficient than a higher rpm ducted fan with blades optimized for a fixed speed? It would seem the friction drag of a lot of surface area would outweigh tip losses? Isn't that why large turbines are more efficient than smaller diameter?
 
This one makes a whole lot of sense.

This is not a joke: This song inspired the development of Opener’s aircraft.

https://m.youtube.com/watch?v=qjLBXb1kgMo

Seriously, an electric aircraft would benefit from a clean sheet design. Notice that the Blackfly has no landing gear? That saves a lot of weight and is amphibious. It does require VTOL capability, though.

Oh, the Blackfly is an Ultralight and can be completely fly-by-wire. A passenger carrying drone!

I worked on electric vehicle development in the 70’s. It’s taken a while(!) and we still are waiting for the Dalhousie batteries to be adopted. See https://electricautonomy.ca/2020/07/10/jeff-dahn-interview/

It’s coming, but the optimal electric aircraft design will not look conventional.

Here I am in 1978. This Vehicle used a 3-phase induction motor with a large inverter system. One of the team members (not pictured) went on to GM to work on the EV-1. When he left GM, he founded Statpower (became Xantrex, then Schneider). If you have ever purchase an inverter system (RV, Boat, PV system, portable power unit), he’s the man!

https://vansairforce.net/community/attachment.php?attachmentid=2184&stc=1&d=1599579303

I don’t have as much hair now.
 

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It does???

Range 25 miles.

Recharge time 5.5 to 7.4 hours for the most commonly found electrical source.

A hundred mile flight thus equates to 4 flight legs, with a minimum of 22 hours charging time to make the flight.

At the 62 mph listed, that is slightly over 1.5 hours flight time, 22 hours charging time. Toss in 10 minutes each charging session just to get hooked up , unhooked and misc.

So, your 100 mile flight has taken 24 hours to accomplish.

Sorry, this doesn't make much sense to me.

Yes, it is interesting tech, and a fun looking craft with an interesting flight capibility.

IMHO for electric flight to get to be more than just a novelty, you need to be close to the performance of gas powered aircraft in; load carrying ability, range, speed, refueling (charging) time and cost.

Dont get me wrong, I am not against electric flight, I am just trying to see the total picture and ignore the koolaid. I look forward to the time I can plug in my plane at night and then go fly out for an hour or two, at 150 mph. Then turn around and fly home and land with the same reserves my gas powered plane has. Plug it in again and be ready for the next flight tomorrow

Maybe someday.........

Take a look at the people behind this.
 
Take a look at the people behind this.

I already did.

No question that they have a boat load of talent, and the possibilities are very intriguing, but they are not there at this time. Lots of development and major breakthroughs still needed to achieve what I stated before --------"IMHO for electric flight to get to be more than just a novelty, you need to be close to the performance of gas powered aircraft in; load carrying ability, range, speed, refueling (charging) time and cost."
 
Need dramatically improved battery tech

Battery technology(power density) will have to dramatically improve before these will be anything more than a science fair project. I'm not saying that what people are doing/trying isn't important. That's how we advance. Motors over engines will be a massive improvement in comfort and reliability, but the batteries just aren't there yet. I've owned an electric car, and it always felt like I was "filling the tank" with an eye dropper. Fun to drive, but not practical for my lifestyle.
 
It does???

Range 25 miles.

Recharge time 5.5 to 7.4 hours for the most commonly found electrical source.

A hundred mile flight thus equates to 4 flight legs, with a minimum of 22 hours charging time to make the flight.

At the 62 mph listed, that is slightly over 1.5 hours flight time, 22 hours charging time. Toss in 10 minutes each charging session just to get hooked up , unhooked and misc.

So, your 100 mile flight has taken 24 hours to accomplish.

Sorry, this doesn't make much sense to me.

Mike, you get First Prize for Missing the Big Picture! :D

Now look at the positives:

- One doesn't need an airport.

- One doesn't need a pilot's license nor a driver's license (it's Ultralight!).

- One doesn't need any flying skills nor specialized knowledge.

- Such a One won't be able to intrude into "precious" airspace and endanger others.

- If it annoys one's neighbors to zoom in/out of one's backyard, trailer it two blocks away and have it land itself back onto the trailer.

- Park it in the garage.

- Range/speed is limited by the aforementioned Ultralight constraint. Lift the constraint, range/speed increases accordingly.

- If one needs more range, make it a gasoline series hybrid with a tiny battery to supply the burst for vertical takeoff. (Oh, and provide a toilet for us young-at-heart.)

The whole point of this exercise isn't to make a better airplane; it is to make a flying thing fit in places where airplanes and helicopters don't, enabled by batteries and Neodymium. (Vacuum cleaners look nothing like brooms.) By that measure this is a smashing success, love-child of a quad-copter and a biplane. I want one!
 
The problem is, to have roughly half the range of your typical RV, you would need about 1800 lbs of batteries. Not feasible for an RV airframe, unless you are just building a science experiment.

Tim
 
I wonder if electric will make it's first mark as a "second plane?"

Hi all,

As technology improves, I wonder if electricity will come into its own as the second plane. I do not know what percentage of pilots have multiple planes, but many that do have a "fun" plane as their second plane. Something you tool around the local area in for an hour fits the bill of an electric plane pretty well. I know Pipistrel made the argument for the Alpha electro that most training flights are an hour. Doing that multiple times a day, day in and day out, while cutting out the maintenance was a big driver for them actually getting the plane to the market. I guess time will tell if this comes to anything or not.

Blue skies,

Geoff
 
My motivation is not environmental or political, but primarily economic - I still can’t swallow the concept of paying $30k for a new Lycoming and $5/gal for a fuel which will only go up in price and get harder to find..

I see no evidence that an electric motor and batteries will be any less to purchase than a Lycoming especially when they get the power density of the batteries up, they will probably require some exotic materials.
Oh, and electricity is not free. Nor is the overhaul, and or disposal of warn out batteries.

The problem is, to have roughly half the range of your typical RV, you would need about 1800 lbs of batteries. Not feasible for an RV airframe, unless you are just building a science experiment.

Tim

Yes, and you have to carry all 1800 lbs from beginning of flight to end. No efficiency advantage to lower weight as you burn off fuel. All flights will be at gross weight from take off to landing.

Happy people are working the issues, but I will be long gone by the time My Lycoming is a relic. ( I guess it already is yet it has survived billions of dollars of internal combustion engine development by the auto industry over the last 100 years)
 
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There were a couple of articles in the last couple of RVators by Van about his self-launching electrical glider. Looks like an electric motor is more at home there. Still, an adequate power source to recharge the batteries appeared to be an issue.

https://www.vansaircraft.com/rvator/

Finn
 
Mike, you get First Prize for Missing the Big Picture! :D

And you sir, get the first prize for selective editing my post to skew the meaning.:D:D

I have included the rest of my statement (bold type) at the end here, please read it.

Now look at the positives:

- One doesn't need an airport.

- One doesn't need a pilot's license nor a driver's license (it's Ultralight!).

- One doesn't need any flying skills nor specialized knowledge.

- Such a One won't be able to intrude into "precious" airspace and endanger others.

- If it annoys one's neighbors to zoom in/out of one's backyard, trailer it two blocks away and have it land itself back onto the trailer.

- Park it in the garage.

- Range/speed is limited by the aforementioned Ultralight constraint. Lift the constraint, range/speed increases accordingly.

- If one needs more range, make it a gasoline series hybrid with a tiny battery to supply the burst for vertical takeoff. (Oh, and provide a toilet for us young-at-heart.)

The whole point of this exercise isn't to make a better airplane; it is to make a flying thing fit in places where airplanes and helicopters don't, enabled by batteries and Neodymium. (Vacuum cleaners look nothing like brooms.) By that measure this is a smashing success, love-child of a quad-copter and a biplane. I want one!

You have made a bunch of statements that refer to ultralight aircraft.

Apples vs. oranges

This is a forum for RV aircraft------but then you already know that.

The opening post asked about putting electric power on a RV. That is what I was addressing, not something in the ultralight world.



Yes, it is interesting tech, and a fun looking craft with an interesting flight capibility.

IMHO for electric flight to get to be more than just a novelty, you need to be close to the performance of gas powered aircraft in; load carrying ability, range, speed, refueling (charging) time and cost.

Dont get me wrong, I am not against electric flight, I am just trying to see the total picture and ignore the koolaid. I look forward to the time I can plug in my plane at night and then go fly out for an hour or two, at 150 mph. Then turn around and fly home and land with the same reserves my gas powered plane has. Plug it in again and be ready for the next flight tomorrow

Maybe someday.........


Done here.
 
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Hi all,

As technology improves, I wonder if electricity will come into its own as the second plane. I do not know what percentage of pilots have multiple planes, but many that do have a "fun" plane as their second plane. Something you tool around the local area in for an hour fits the bill of an electric plane pretty well. I know Pipistrel made the argument for the Alpha electro that most training flights are an hour. Doing that multiple times a day, day in and day out, while cutting out the maintenance was a big driver for them actually getting the plane to the market. I guess time will tell if this comes to anything or not.

Blue skies,

Geoff


Probably true, but for the next student the batteries will be dead..........
 
Recharge time

Supposedly the recharge time is 45 minutes. When I was doing training our club ran 2-3 sorties a day on each trainer, which would be very doable with this recharge time. The "refuel" cost for a flight was $3 for the electricity.

I am not saying this is the be-all and end-all, it just seems like they are getting closer to making this make sense, at least for some use cases.

Blue Skies

Geoff
 
Supposedly the recharge time is 45 minutes. When I was doing training our club ran 2-3 sorties a day on each trainer, which would be very doable with this recharge time. The "refuel" cost for a flight was $3 for the electricity.

I am not saying this is the be-all and end-all, it just seems like they are getting closer to making this make sense, at least for some use cases.

Blue Skies

Geoff

About the same as my local evening flight.
 
TomAniello said:
My motivation is not environmental or political, but primarily economic - I still can’t swallow the concept of paying $30k for a new Lycoming and $5/gal for a fuel which will only go up in price and get harder to find..
I see no evidence that an electric motor and batteries will be any less to purchase than a Lycoming especially when they get the power density of the batteries up, they will probably require some exotic materials.
Oh, and electricity is not free. Nor is the overhaul, and or disposal of warn out batteries.
Corrected the attribution of that quote. It wasn't me.
 
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