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Jul 17, 2011, 12:55 PM
get your drive right...!

eCalc: Q&A for propCalc, fanCalc, heliCalc, xcopterCalc


To be able to support you best, please alwaly post a screen shot of your calulation..

Did you read something about eCalc in your prefered RC Magazine? ...please send us a scan of the article. Thanks

Thank you for supporting eCalc - the most reliable RC Calculator on the Web.

Kind Regards
Last edited by eCalc; Jun 06, 2015 at 01:52 PM.
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Jul 18, 2011, 07:43 PM
Registered User
Hi Markus, and thanks for this great tool.

- coaxial arrangements are so common - are you working on an extension to make proper calculations for these?
- the battery table lists A123 cells (26650, 2.3Ah) as 15/20C. My info says that (genuine) A123 26650's are 30C rated.
Jul 19, 2011, 07:19 AM
get your drive right...!
@jes1111 mentioned some month ago - too complex for the time.... sorry
Jul 19, 2011, 08:42 AM
Registered User
Yes, I recall - but are you intending to upgrade the tool in the future?

And the A123 C rating?
Jul 19, 2011, 10:50 AM
get your drive right...!

I'll check that....

I got an idea about coax-Multi-Copter. Do you have some figuers on your's?

I need your setup, flying weight, current to hover, max. current....

cheers markus
Jul 19, 2011, 11:03 AM
Registered User
I don't have one flying yet (which is one reason I'd like to see coax added to your tool ).

I agree it is very complex. You obviously understand more about this than I do, but my guess is that if you calculate the pitch speed of the top prop (at hover rpm) then apply that to the calculations for the bottom prop you should be in the right ballpark. There will be some inaccuracy for anything but "continuous hover in still air" since the craft will be varying rpm constantly to manoeuvre, but since it will be both sides (+/-) of the hover rpm it should average out.
Jul 19, 2011, 04:28 PM
get your drive right...!
will update this in the next days.....

cheers markus
Jul 21, 2011, 06:24 AM
get your drive right...!
the A123-30C are available

cheers Markus
Jul 22, 2011, 07:51 AM
Registered User
I have used the ecalc quite a lot for my projects and it has been much more accurate than expected. For example with Turnigy 3648-850kv and Aeronaut Cam Carbon props the static current is within couple of amps. Nice online tool indeed.
Jul 22, 2011, 10:31 AM
Registered User
snoopy_schulz's Avatar
Hi eCalc

I have tested your propCalc versus my own drive calculator. The results are very similar.

My question is, do you have source's for prop data from internet. I'm using prop data from aeronout and from

Best regards
Jul 22, 2011, 12:57 PM
homo ludens modellisticus
Ron van Sommeren's Avatar
Micha, Markus,

Check the Aeronaut, APC and Slowflyprops tabs in

Prettig weekend Ron
diy motor tipsDrive Calculator
diy motor groupCumulus MFC
Last edited by Ron van Sommeren; Jul 22, 2011 at 01:04 PM.
Nov 07, 2011, 11:32 AM
get your drive right...!

eCalc - Release 5.15


with immediate effect the new release 5.15 is available.

What's new? ...please see the relase note:

cheers markus
Nov 09, 2011, 10:47 PM
Registered User

You have a great tool and provide the rc group a great service. I will donate a little something on my next visit.

I have a wuestion that might be a little silly but perhaps you can indulge me. A fully charged lipo is at 4.2 but ecalc shows the full voltage to be only 3.7. Why is this? Won't real world results be much different because of this?

Nov 13, 2011, 01:33 PM
get your drive right...!

3.7V is the rated voltage. if you have a look on a dicharge diagramm at high C rate you will see your Lipo is not able to maintain the 4.2V (due internal resistant). it will drop with amp draw towards your rated voltage....

a typical discharge diagram:

cheers markus

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