How far are we from the perfect electric "homebuilt" ?

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Speedboat100

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I mean that if we could get the most unforeseen ideas implemented to an electric aeroplane...how far are we from this perfect situation ?

I assume it means:

1. New structural ideas
2. Better engines
3. Battery developement
4. Aerodynamical innovations

This is very necessary to get developement fast..as the energy density of batteries is about 1/20th at the best cases from fuel.

I think we can make 65-70 % progress compared to the systems today flying....in 10 years.

Electric engines are simple and light...which is a good thing ( I opened one ).
 

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Speedboat100

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I read somewhere that the biggest mistake is trying to convert an existing type of gas powered plane to an electric one....is there truth to this. I think there is.
 

radfordc

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New designs and motors may help a little, but it's batteries that are the critical path to practical electric planes. Lithium-polymers are 2-3 times better than Nickle Cadmiums...we now need something at least 2-3 times better than Li-Po's.
 

Speedboat100

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That reduction gear on bike hub motors would already be one advancement...you could run a bigger dia prop.
 

stanislavz

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A direct drive motor is going to be much heavier than a geared motor.
In most cases no. You still need constant power in tens of minuts. Not few second burst. Energy packed to dense - active water cooling to cooe with.

Make it bigger and flatter - a lot of active area for cooling.
 

Hephaestus

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Psru design for electric is no easier than gas.

Even in the RC world with 40 years of practice gearboxes for electric motors don't have great reliability.
 

stanislavz

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All still goes to power / cooling surface. You cant put more than 1.2 Tesla in iron core before saturation. Independant of shape.

And pancake shape will provide way much cooling area, than more compact shape. Plus automaticly will make less rpm and more torque.
 

Speedboat100

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All still goes to power / cooling surface. You cant put more than 1.2 Tesla in iron core before saturation. Independant of shape.

And pancake shape will provide way much cooling area, than more compact shape. Plus automaticly will make less rpm and more torque.

Yes I agree...secret lies there...maybe a hole in the middle ? Hollow shaft ?

https://en.wikipedia.org/wiki/Tesla_(unit)
 

Hephaestus

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caplus.png
These are what massive induction motors that generate massive heat look like. First you get cooling fins, then you get fans to direct flow appropriately, then you get into water cooling.

The technology is already out there - we use it daily on industrial sites. Simply a matter of assessing the needs then addressing cooling in a step by step methodology.
 

stanislavz

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Yes I agree...secret lies there...maybe a hole in the middle ? Hollow shaft ?

https://en.wikipedia.org/wiki/Tesla_(unit)
Not only.. I do like to imagine pancake motor (inrunner or outrunner) - as a set slices of original stator, cuteed and joined one to one, forming better cooling area and higher leverage. So - square motor, cutted into 4 slices, and joined end to end, will have 4 time torque, and 4 time less rpm. And (if we only take side cooling area into calculation) and 4 times of cooling area :) But some extra copper in coils. All else - magnets/core are in same size mass
 

Speedboat100

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Hollow shaft could bring cooling air to the batteries.

Then the prop ( and spinner ) should be a integral part of the rotator...and the stator is belted where the spinner starts in a regular plane....with a gaping hole in the middle to bring smoothly air to the batteries. This saves about 1.5 meters in the length. Or ½ meter in a smaller AC.
 
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