electric airplane

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MoleKule, I was considering the motor's draw in KW is not the output in HP. Possibly, the motor KW rating is it's output. Which means it's battery draw is considerably higher. As the motor/controller efficiency is likely to be about 90%.

As far as using ram air for pressurization, that is generally not effective. There is very little to be gained by ram pressure. A good way for a pilot to look at this situation is to review the indicated airspeed decline during a climb with a steady TAS (true airspeed). We have a way to use only ram pressure on our Gulfstream jet. At best, it can help move air through the cabin to clear smoke.
 

MolaKule

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MoleKule, I was considering the motor's draw in KW is not the output in HP. Possibly, the motor KW rating is it's output. Which means it's battery draw is considerably higher. As the motor/controller efficiency is likely to be about 90%.

As far as using ram air for pressurization, that is generally not effective. There is very little to be gained by ram pressure. A good way for a pilot to look at this situation is to review the indicated airspeed decline during a climb with a steady TAS (true airspeed). We have a way to use only ram pressure on our Gulfstream jet. At best, it can help move air through the cabin to clear smoke.
From the info here, https://www.eviation.co/aircraft/#Alice-Specifications
it appears they de-rated the engine by about 10kW because here https://www.flyingmag.com/story/air...o-optimized-flight-electric-propulsion-units/ the rating is "...850 shp/650kW/3200 Nm-class.." and I am taking the data to mean shaft horsepower resulting from the electrical-to-mechanical conversion, using the magniDrive-100, a 170kW inverter/motor controller power electronics units.

I am theorizing here that this controller system converts DC battery power to create an internal three-phase or multiphase stator waveform which would increase overall efficiency. I am also assuming here the rotor is constructed of the same high-flux density permanent magnets as used in EV motors.

Assuming those inverters are 90% efficient the electrical power required would be 1.1XEngine Rating, but that is a power system/power control problem.

As I have stated before, and since very little detailed information is forthcoming at this time, we can only postulate what they might be using for each aircraft system. But educated guessing can be a fun exercise. :):cool:
 
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There is no question electric motors can be made to make the HP. Elon Musk is already doing it. However, when I see absurd claims of low weight, lower than normal drag results and good performance and range claims, I immediately start the questioning. The weight claim is the first one that needs to be addressed. Carrying 5 tons of battery, wiring and and controllers, means the MGTOW will be 20K, as there is no way to carry cargo, airframe and crew. Unless we are simply transporting packing peanuts.

But even so, there are other factors in the calculations. Twin engine (yes, that includes electrics) will need enough HP on a single engine to maintain an adequate (and REQUIRED) rate of climb. The 16,500 pound King Air 360 has 2ea PT6-60A engines, each making 1050SHP (1113ESHP) for a total of 2100 Shaft HP, and another 126HP from exhaust thrust. For a grand total of 2226 takeoff HP. It also has a 57 foot high aspect ratio wing. Requires a 4000 foot runway and climbs at a claimed 2500 FPM (real world under 2000FPM)

Any way this goes, the electric is underpowered and overweight.
 
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There is no question electric motors can be made to make the HP. Elon Musk is already doing it. However, when I see absurd claims of low weight, lower than normal drag results and good performance and range claims, I immediately start the questioning. The weight claim is the first one that needs to be addressed. Carrying 5 tons of battery, wiring and and controllers, means the MGTOW will be 20K, as there is no way to carry cargo, airframe and crew. Unless we are simply transporting packing peanuts.

But even so, there are other factors in the calculations. Twin engine (yes, that includes electrics) will need enough HP on a single engine to maintain an adequate (and REQUIRED) rate of climb. The 16,500 pound King Air 360 has 2ea PT6-60A engines, each making 1050SHP (1113ESHP) for a total of 2100 Shaft HP, and another 126HP from exhaust thrust. For a grand total of 2226 takeoff HP. It also has a 57 foot high aspect ratio wing. Requires a 4000 foot runway and climbs at a claimed 2500 FPM (real world under 2000FPM)

Any way this goes, the electric is underpowered and overweight.

Electricity isn't the problem. Electric is great if you don't need to lug fuel around, like a trolley bus, subway, or an electric locomotive running off a catenary. Didn't Tesla talk about wirelessly transmitting electricity through the air?

Fuel cells still aren't a bad idea.
 

MolaKule

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But even so, there are other factors in the calculations. Twin engine (yes, that includes electrics) will need enough HP on a single engine to maintain an adequate (and REQUIRED) rate of climb. The 16,500 pound King Air 360 has 2ea PT6-60A engines, each making 1050SHP (1113ESHP) for a total of 2100 Shaft HP, and another 126HP from exhaust thrust. For a grand total of 2226 takeoff HP. It also has a 57 foot high aspect ratio wing. Requires a 4000 foot runway and climbs at a claimed 2500 FPM (real world under 2000FPM)

Any way this goes, the electric is underpowered and overweight.

This concept does seem to have overly optimistic specifications and expectations. :unsure:

And we haven't even taken into account as yet the power required for the flight deck avionics and weather radar.

As for the King Air: (y)

Collins Aerospace Pro Line Fusion avionics suite - Three 14-inch touch-screen displays - Synthetic vision system (SVS) - Graphical flight planning - Integrated charts and maps*

MultiScan Weather Radar system (WXR)

Engine-indicating and crew-alerting system (EICAS)

I did a lot of design and verification work on the SVS, EICAS, and the MultiScan Weather Radar system (WXR) (last project).

It is hard to beat the PT6A powerplant.
 
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so
um
how long does it take to recharge this battery pack? :eek::eek::eek:
i mean, we do want to offload cargo, load cargo and then fly off to the next destination.
cant you just pop out that massive battery pack and pop in another thats fully charged? :unsure:
 
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so
um
how long does it take to recharge this battery pack? :eek::eek::eek:
i mean, we do want to offload cargo, load cargo and then fly off to the next destination.
cant you just pop out that massive battery pack and pop in another thats fully charged? :unsure:

Yeah - that's the idea to speed up turnaround time. The battery pack should weigh about 4 tons and will obviously need equipment get the old one out and the new one in place.
 
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My question is whether the claimed flight times for these electric planes includes the required reserves; 30 minutes for VFR and 45 minutes for IFR.

It seems most are claiming about a 45 minute flight time at cruise. Is that 45+45 or 45 total?

Yea, the DHL plane should be great for delivering envelopes across town. ;)

Ed
 
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Yeah - that's the idea to speed up turnaround time. The battery pack should weigh about 4 tons and will obviously need equipment get the old one out and the new one in place.

and what about the firefighting (hazmat) equipment needed for when one these batteries has an issue?

DPS had to block off I35 here for several hours when a prius was in an accident and the hazmat team was brought in to clean it up.

would electric planes be in their own "terminal/gates" since an issue with the batteries in the close proximity of jp1 might be....bad ?
 
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My question is whether the claimed flight times for these electric planes includes the required reserves; 30 minutes for VFR and 45 minutes for IFR.

It seems most are claiming about a 45 minute flight time at cruise. Is that 45+45 or 45 total?

Yea, the DHL plane should be great for delivering envelopes across town. ;)

Ed

They'll likely have some sort of backup. I heard of a fuel cell powered plane that was supposed to have a gas turbine as a backup power source in case of the battery malfunctioning.
 
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and what about the firefighting (hazmat) equipment needed for when one these batteries has an issue?

DPS had to block off I35 here for several hours when a prius was in an accident and the hazmat team was brought in to clean it up.

would electric planes be in their own "terminal/gates" since an issue with the batteries in the close proximity of jp1 might be....bad ?

I don't think that really matters for a cargo plane, which don't use gates per se. There are known techniques for putting out lithium-ion battery fires. It's obviously going to be something they're going to have to prepare for.
 
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As mentioned above, the IFR reserves are going to be the big hurdle for E-aircraft. As at the moment, it can't be done in many locations.

91.167,,, Complete the flight to the first airport of intended landing;

(2) Except as provided in paragraph (b) of this section, fly from that airport to the alternate airport; and

(3) Fly after that for 45 minutes at normal cruising speed.
 
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1HP is defined as the ability to lift 550 pounds, one foot in one second (a paltry 60 FPM for us pilots). When lifting a weight, it does not matter (all that much) if we use ropes and pulley, or a ramp or a wing. Or for that matter, a "lock" full of water to raise a boat. The work being performed is the same. With the wing creating some lift induced drag, worsening the equation somewhat.

Lifting an Alice aircraft to realistic altitudes takes a known amount of energy.... Something the battery can't easily provide.

Again, there is a reason the 16,500 pound King Air has over 2,200HP available, and the 9,600 pound PC-12 has 1,350. They need it to get to 25,000 or even 30,000 feet at max gross weight.

It should come as no surprise the Alice is designed for a 10,000 foot cruise altitude. Going really high and bucking typical higher altitude headwinds might deplete the battery to the point of massive range reduction.
 
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I think 1 HP are dangerous at both ends and uncomfortable in the middle...

07WCRM35.JPG
 
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I assume the engines are just electric motors connected to the props.

I wonder how they handle air conditioning and pressurization. Vapor cycle and compressors? I know it’s been done before on larger A/C (DC-8, for example).

That would use lots of electricity and decrease range quite a bit.
Open the windows !
 
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