
Siemens electric air plane engine, how does it stack up to Tesla engines? - AndHeiberg
http://andreas.heiberg.io/blog/siemens-electric-air-plane-engine-how-does-it-stack-up-to-tesla-engines/
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ulfw
Why is this article posted? None of the numbers make sense. Tesla weight 32kg,
Tesla Roster [sic] 1235 kg.

Well then...

~~~
AndHeiberg
Yeah my bad, had that thought at 6 in the morning. I've updated it. My central
question still stands though. Tesla seems to outperform the Siemens engine by
quite a lot, why are did they make such a big splash?

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_Codemonkeyism
The "BMW 7 Series" motor weights 2.3t? Or if it's not the motor weight but the
car weight, a Tesla weights 32kg?

~~~
raverbashing
I think the table mixed motors and cars (first motors then cars), so you have
a comparison car power/weight and motor power/weight

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stannol
Do the 32kg include the inverter and reduction gear? I highly doubt they do.
My guess is that with those included it weighs AT LEAST 100kg, probably closer
to 200kg. I can't find any details on what Siemens includes in their weight
figure. Even if all the numbers are comparable (I'm pretty sure they are not),
the Siemens motor (apart from being flight rated) is able to continuously
output 260kw, the Tesla motor isn't even close to that. I've personally tried
it a few times on the Autobahn and the Tesla limits the output to about 100kw
(displayed) after less than a minute of full throttle.

~~~
AndHeiberg
+9001 this!

> My guess is that with those included it weighs AT LEAST 100kg, probably
> closer to 200kg.

Interesting, that would put the power to weight ratio down to combustion
engine levels.

I found this [http://www.teslarati.com/tesla-model-s-
weight/](http://www.teslarati.com/tesla-model-s-weight/) that supports your
thought by putting it at 150 kg.

> I can't find any details on what Siemens includes in their weight figure

Well they don't have a transmission so that shouldn't be a concern.

> is able to continuously output 260kw, the Tesla motor isn't even close to
> that. I've personally tried it a few times on the Autobahn and the Tesla
> limits the output to about 100kw (displayed) after less than a minute of
> full throttle.

In did try to correct for this sort of thing by picking one of the lower kW
ratings for the Tesla. I was not aware it was that drastic. If we account for
this the Tesla is almost in Honda accord territory. That's rather
disconcerting given Musk citing figures like the ones I outlined.
[https://youtu.be/PULkWGHeIQQ?t=41m30s](https://youtu.be/PULkWGHeIQQ?t=41m30s)

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thedrbrian
Why are we comparing motors to whole vehicles?

Plus the tesla motor isn't flight rated

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AndHeiberg
See other comments I had it mixed up for sec there.

What's the difference between a flight rated motor and a no flight rated one
mechanically? Why is the comparison between Tesla and Siemens engines unfair?

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raverbashing
> What's the difference between a flight rated motor and a no flight rated one
> mechanically?

\- A crapton of certification

\- Increased reliability

\- Some materials may be different for weight purposes

\- They also have different power/torque characteristics, also depend on the
type of propeller used (is it a constant speed propeller?)

~~~
AndHeiberg
[This]([https://forums.teslamotors.com/forum/forums/motor-
rpm-155-mp...](https://forums.teslamotors.com/forum/forums/motor-rpm-155-mph))
does suggest that the RPM of 18.000 is quie different than the 2.500 mentioned
for the Siemens.

I do think the figure of 32 kg for the Tesla motor includes the fixed gear
though. So I don't so why that would be of any concern.

idk I still don't understand where the unique ability of the Siemens engine
is. Obviously not the power to weight ratio. Not certification as it's still
in development.

As for materials and power/torque I have no clue.

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the_mitsuhiko
Surely the problem is not the engine weight but the battery weight.

~~~
sp332
Saving weight anywhere on an airplane is a win. The new engine claims to have
more power output than other engines of the same weight.

~~~
AndHeiberg
Yeah exactly, but given the numbers, it doesn't seem to outperform Tesla's
engines? Perhaps they're also taking in to account the power usage as battery
weight is more significant in planes... idk would love if it someone could
help me understand it better though.

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Shivetya
don't forget that the power available to the Tesla motors decreases as the
battery is used up. Seems odd, but as usable stored power decreases you are
not able to pull as much from the battery anymore.

then there is that whole bugaboo of battery weight.

~~~
AndHeiberg
Is this different in the Siemens engine though? Is that why they say "delivers
a __continuous __output of about 260 kilowatts " emphasis added. I guess all
that means is that they're really able to deliver more power than advertised
on a full charge?

