Electric Motor Mooney Conversion

[65C_flier]

Hi all,

Has anyone thought much about converting a Mooney to an electric motor? Might be a few years (decades?) away, but it seems like it might be feasible eventually. Some rough math for a J (using metric, sorry but its easier). Interested in whether anyone has thought more about it.

• 200hp (presumably at the output shaft) = 150kw. Electric motors are around 3x more efficient, but we still need 150kW going to the prop, so a 150kW electric motor is required
• Weight available: remove IO-360 engine 300lb, 64Gal fuel 384lb = 684lb (310kg). Might scrape together another 10kg in fuel components. 
• Assume 50kg for (a theoretical 90% efficient) 150kW output motor, assume new prop same weight as old prop, 20kg for battery controllers gives 250kg available for batteries
• Power required for takeoff & climb (5 mins at 100% and 10 mins at 75%) = 31.25 kWh motor output (34.7 kWh battery input for 90% efficient motor) 
• Cruise at 60% power = 90 kWh per hour of cruise (100 kWh input)
• Current batteries are around 250 Wh/kg or 4kg per kWh. Battery weight required: takeoff/climb 139kg, cruise 400kg/hr.
• With 250kg to play with that only allows 15 min takeoff/climb and 17 mins cruise (no reserve). Not very useful. Even if you throw another 200kg of batteries on the back seat, you only get 47 min cruise (no reserve). 
• If (when?) batteries improve to 500 Wh/kg, that gets us to 54min cruise (no reserve) or 1.9hr (no reserve) with an extra 200kg of batteries.
• So it would take more like 2500 Wh/kg to get something comparable to what we have currently got (5.3hrs with 45min reserve). Charging rates would also rule out 2 long hops in a day, so we are probably never going to get anything comparable to what we have currently go, but I wonder what people's threshold would be to make it feasible.

 

[Browncbr1]

Electric might be ok for novelty, but I don’t see it being practical without a new paradigm in battery technology.  
 

I think a FADEC turbo diesel jetA burner is a better option.  

[N201MKTurbo]

Putting a 200hp electric motor in a Mooney isn't that much of a technical challenge. 

Managing the extension cord it the challenge!

[McMooney]

this would def work : Ford Eluminator Motor Comes From Mustang Mach-E GT, Costs $3,900 (fordauthority.com)

just have to worry about batteries.

 

 

[N201MKTurbo]

  On 11/17/2021 at 2:15 PM, McMooney said:

this would def work : Ford Eluminator Motor Comes From Mustang Mach-E GT, Costs $3,900 (fordauthority.com)

just have to worry about batteries.

 

 

Expand  

I wonder if it would support a propeller?

[philiplane]

If you can increase the gross weight to 4900 pounds, you can almost equal the performance and range of the avgas engine. 

That will allow you to install the 2400 pound battery needed to replace the 400 pounds of avgas. 

But with that weight increase, we will need more power, and with more power, we will need a bigger battery....

[RobertGary1]

The 64gal of gas you mentioned is the largest limitations. That is one heavy Mooney. There have been a few times in Mexico I’ve filled to 64gal but I could count them on one hand in the last 20 years. No way would I fly a Mooney that was stuck at max fuel weight. 

[1964-M20E]

The power density of batteries is nowhere near the power density and mobility in gasoline, jet A or diesel.

[EricJ]

  On 11/17/2021 at 2:49 PM, N201MKTurbo said:

I wonder if it would support a propeller?

Expand  

Without a torque/hp curve it might need a transmission to turn the prop at >200 hp, so the transmission could be designed for whatever load the prop would make.   It says it makes 317 ft-lbs, and if the torque curve is flat, which isn't an unreasonable assumption for an electric motor, it has to spin 3313.5 rpm to make 200 hp, or faster for more hp, which would be cool, too.    Either way, it needs a transmission, so that solves the problem of mounting the prop, but adds weight and cost and development effort.

 

[N201MKTurbo]

  On 11/17/2021 at 5:18 PM, EricJ said:

Without a torque/hp curve it might need a transmission to turn the prop at >200 hp, so the transmission could be designed for whatever load the prop would make.   It says it makes 317 ft-lbs, and if the torque curve is flat, which isn't an unreasonable assumption for an electric motor, it has to spin 3313.5 rpm to make 200 hp, or faster for more hp, which would be cool, too.    Either way, it needs a transmission, so that solves the problem of mounting the prop, but adds weight and cost and development effort.

 

Expand  

Tempe Town Lake is limited to electric boats. I've always thought about building a bad ass electric boat for the lake. I bet I could ski behind this one.

[EricJ]

  On 11/17/2021 at 5:33 PM, N201MKTurbo said:

Tempe Town Lake is limited to electric boats. I've always thought about building a bad ass electric boat for the lake. I bet I could ski behind this one.

Expand  

I kayak there and, unfortunately, they limit electric boats to wakeless speed.  

Maybe that means you should make a hydrofoil instead. 

Edited November 17, 2021 by EricJ

[N201MKTurbo]

  On 11/17/2021 at 5:53 PM, EricJ said:

I kayak there and, unfortunately, they limit electric boats to wakeless speed.  

Maybe that means you should make a hydrofoil instead. 

Expand  

I like your thinking!

[65C_flier]

  On 11/17/2021 at 3:48 PM, RobertGary1 said:

The 64gal of gas you mentioned is the largest limitations. That is one heavy Mooney. There have been a few times in Mexico I’ve filled to 64gal but I could count them on one hand in the last 20 years. No way would I fly a Mooney that was stuck at max fuel weight. 

Expand  

I usually takeoff at MTOW (family and full fuel). Doesn't seem to be a problem, but I agree staying at MTOW for the full flight is a penalty, as is stress on the airframe landing at MTOW.

[McMooney]

  On 11/17/2021 at 8:44 PM, 65C_flier said:

I usually takeoff at MTOW (family and full fuel). Doesn't seem to be a problem, but I agree staying at MTOW for the full flight is a penalty, as is stress on the airframe landing at MTOW.

Expand  

I'm pretty much always at max fuel,  52Gals though.  rather leave people than gas

[GeeBee]

You might watch the video in this article. It is a little more complicated than just slapping in an electric motor and batteries. Believe it or not, you need a cooling...or heating system to both control the batteries and the motor temps because you are unleashing a whole lot of watts, real fast. Mind you, this is an LSA weight airplane.

 

https://www.avweb.com/multimedia/deland-sport-showcase-pipistrel-velis-electric-trainer-debuts/?MailingID=770&utm_source=ActiveCampaign&utm_medium=email&utm_content=Deland+Showcase%2C+A321neos+Sold+Out&utm_campaign=Deland+Showcase%2C+A321neos+Sold+Out-Monday%2C+November+15%2C+2021

[WaynePierce]

I bought my Mooney to go far, quickly. Until electric has advanced to the point where I can go far, I'm not interested. Same reason I have a gas burning automobile event though the go far isn't nearly as quickly :-)

[Hank]

  On 11/17/2021 at 9:37 PM, WaynePierce said:

I bought my Mooney to go far, quickly. Until electric has advanced to the point where I can go far, I'm not interested. Same reason I have a gas burning automobile event though the go far isn't nearly as quickly :-)

Expand  

I'm with you, brother!

[RobertGary1]

  On 11/17/2021 at 8:44 PM, 65C_flier said:

I usually takeoff at MTOW (family and full fuel). Doesn't seem to be a problem, but I agree staying at MTOW for the full flight is a penalty, as is stress on the airframe landing at MTOW.

Expand  

I rarely do 6 hour legs. The performance difference of a lighter Mooney vs heavier is very noticeable. If you need to plan to land with a 4 hour reserve the flight probably isn't worth it

 

-Robert

[Igor_U]

  On 11/17/2021 at 12:45 PM, 65C_flier said:

Hi all,

Has anyone thought much about converting a Mooney to an electric motor? Might be a few years (decades?) away, but it seems like it might be feasible eventually. Some rough math for a J (using metric, sorry but its easier). Interested in whether anyone has thought more about it.

• 200hp (presumably at the output shaft) = 150kw. Electric motors are around 3x more efficient, but we still need 150kW going to the prop, so a 150kW electric motor is required
• Weight available: remove IO-360 engine 300lb, 64Gal fuel 384lb = 684lb (310kg). Might scrape together another 10kg in fuel components. 
• Assume 50kg for (a theoretical 90% efficient) 150kW output motor, assume new prop same weight as old prop, 20kg for battery controllers gives 250kg available for batteries
• Power required for takeoff & climb (5 mins at 100% and 10 mins at 75%) = 31.25 kWh motor output (34.7 kWh battery input for 90% efficient motor) 
• Cruise at 60% power = 90 kWh per hour of cruise (100 kWh input)
• Current batteries are around 250 Wh/kg or 4kg per kWh. Battery weight required: takeoff/climb 139kg, cruise 400kg/hr.
• With 250kg to play with that only allows 15 min takeoff/climb and 17 mins cruise (no reserve). Not very useful. Even if you throw another 200kg of batteries on the back seat, you only get 47 min cruise (no reserve). 
• If (when?) batteries improve to 500 Wh/kg, that gets us to 54min cruise (no reserve) or 1.9hr (no reserve) with an extra 200kg of batteries.
• So it would take more like 2500 Wh/kg to get something comparable to what we have currently got (5.3hrs with 45min reserve). Charging rates would also rule out 2 long hops in a day, so we are probably never going to get anything comparable to what we have currently go, but I wonder what people's threshold would be to make it feasible.

 

Expand  

You significantly underestimate the weight of the electric motor, number of controllers, it's cooling system and such. Heavy gage wiring weights a lot. as well. No batteries installed, yet.

I know of company that was (and still is) involved in a few of these projects that you can read about and is mind boggling to me that real engineers come with such concepts. I give them almost zero chance to succeed (and not only due to weight). In one demonstrator, bare EPU (electric motor) is heavier then replacing PW123 turbine and has only 60% of the power.

Then there's was an electric Grand Caravan that exceeded original MTOW with test pilot only... what's the point?

It's a really good topic to discuss over beer sometime (can't type) but for NDA.

 

But hey, if not electric, we can all discuss Turbine Mooney like one in another thread... 

[RobertGary1]

  On 11/17/2021 at 11:23 PM, Igor_U said:

You significantly underestimate the weight of the electric motor, number of controllers, it's cooling system and such. Heavy gage wiring weights a lot. as well. No batteries installed, yet.

I know of company that was (and still is) involved in a few of these projects that you can read about and is mind boggling to me that real engineers come with such concepts. I give them almost zero chance to succeed (and not only due to weight). In one demonstrator, bare EPU (electric motor) is heavier then replacing PW123 turbine and has only 60% of the power.

Then there's was an electric Grand Caravan that exceeded original MTOW with test pilot only... what's the point?

It's a really good topic to discuss over beer sometime (can't type) but for NDA.

 

But hey, if not electric, we can all discuss Turbine Mooney like one in another thread... 

Expand  

I worry we only have a limited amount of time to get this to work or give up aviation. We're seeing more airports pushed towards closing in California due to locals saying that gas airplanes flying over them is an environmental hazard. It doesn't have to be true to be said and that is often enough. Frame it as rich guys dropping HC's on poor neighborhoods affecting children and that's the end of your airport.

In my town we had a bunch of people try to outlaw leaf blowers because they thought it was unsafe to run them close to other people's homes.

 

-Robert

[RLCarter]

I’ll stick with fossil fuels….

[toto]

  On 11/17/2021 at 8:53 PM, McMooney said:

I'm pretty much always at max fuel,  52Gals though.  rather leave people than gas

Expand  

I’m almost always full (64gal) when the aircraft is parked. Three reasons, any of which might be nonsense:

* The only time you can have too much fuel in an airplane is when you’re on fire

* Leaving tanks less than full can allow water to condense in the tanks

* Tank seals can dry out when tanks aren’t kept full 

[GeeBee]

  On 11/17/2021 at 11:59 PM, RobertGary1 said:

I worry we only have a limited amount of time to get this to work or give up aviation. We're seeing more airports pushed towards closing in California due to locals saying that gas airplanes flying over them is an environmental hazard. It doesn't have to be true to be said and that is often enough. Frame it as rich guys dropping HC's on poor neighborhoods affecting children and that's the end of your airport.

In my town we had a bunch of people try to outlaw leaf blowers because they thought it was unsafe to run them close to other people's homes.

 

-Robert

Expand  

The issue is lead, not gasoline. Get rid of the lead, that argument becomes very weak.

 

[RobertGary1]

  On 11/18/2021 at 12:56 AM, GeeBee said:

The issue is lead, not gasoline. Get rid of the lead, that argument becomes very weak.

 

Expand  

Weak or not it works. 

[RobertGary1]

  On 11/18/2021 at 12:11 AM, toto said:

I’m almost always full (64gal) when the aircraft is parked. Three reasons, any of which might be nonsense:

* The only time you can have too much fuel in an airplane is when you’re on fire

* Leaving tanks less than full can allow water to condense in the tanks

* Tank seals can dry out when tanks aren’t kept full 

Expand  

500fpm vs 1200 fpm in my experience.