edited

Originally Posted by prinz

louis,


a little suggestion:
you should beginn to differencing data for the older "G1" and the newer "G2" if the special motortype was/is built with both statorshapes.
the difference in kv and stiffness for the same winding is significant.

some users try to use the scorpion calc data for the older G1 to find a good dimensioning for their models and are wondering, if the real data abberate from the precalculation!

second question:
how do you meassure your R i?
I have in all my motors about 130-150% copperfilling of the manufacturer winding - but I calculate a bit more ohmical resistance for the winding compared to your data for the manufacturer winding.
for my guess is your tool much to optimistic!
have a look of the attached comparison made from the same data!
ralph
www.powercroco.de

Hi Ralph
Next release I have to add "G1" suffix on all G1 motors
I suppose Georges sent to me G1 versions
For the six 40xx I don't know what I received

For Rm I measure at 20°C, directly on the connectors
My software makes a Rm evaluation regarding temperature.
But my Kth (°C/W) is measured on the flange
So maybe there is a temp. gradient between copper and flange
It depends also of running time (0.5 minutes maybe doesn't corresponds to your test)
Also my freeware takes into account an ESC internal resistance (including ESC wire lengths, and connectors) that is evaluated.
It is possible that my freeware is slightly optimistic, but my goal was to give an order of magnitude.
Sure, as Drive-Calc is based on a dynamical Rm averaged for several real world tests, with the exact ESC, it could be better.
But if you change ESC or voltage, maybe the accuracy is less
Louis

edited

Originally Posted by Fourdan

Hi
In the library, I can put myself if I know two coefficients, got after measurements. So I am interested when vendors send me props I have not.

If you have results for any Scorpion motor + any prop
Voltage at ESC input (not the pack config, that is too much uncertain)
DC Current at ESC input
rpm
thrust if possible
I can do, if I am confident

Another solution is to use "generic" with default coeff Kpower=Kthust=1
Scorpion Calculator is compiled with the prop library

Louis

Thanks for the reply. Thrust is going to be difficult to get but I'll supply what numbers I can get for these new props.

Hi
Scorpion Calc is up-dated
v3.06 for Metric or Imperial (preferences are saved)
Go to post#1 in this thread
Please destroy older versions (but first ... test the new)
Recently tested S4025-10, S4025-12 and S4025-16
New prop APC 18x10E (#228 n100W = 2997 rpm)
Louis

edited

Originally Posted by prinz

and the G1 / G2 distinction ?

ralph

www.powercroco.de

Hi Ralph

For now I have no precise info-advice from Georges or Lucien to place a suffix and to complete the list as a function of versions, as I told them. They are very busy .. sure.

But you are right ... it would be a good improvement.

I think that Georges & Lucien are listening about that.

Louis

Louis,

Excellent work. I have been using my own excel spreadsheets for years to get better results than commercially available software. However, your version gives the most accurate results I have seen.

I actually measure the Kv, Io, and Rm of each of my motors. If I plug these values into your application, I get extremely accurate predictions on both current draw and prop rpm. This is based on recording data from an eagletree logger both on the ground and in-flight.

I do have one minor issue. It seems that the pitch speed calculation is off if you use a gearbox. For example, if I put the gearbox ratio at 4, the motor speed and prop speed are correct but the pitch speed is low by the multiple of the gearbox. I can just multiply by the gearbox ratio to get the correct value, but I thought you might want to fix it.

Thanks,

Steve

Originally Posted by stevemangum

Louis,

Excellent work. I have been using my own excel spreadsheets for years to get better results than commercially available software. However, your version gives the most accurate results I have seen.

I actually measure the Kv, Io, and Rm of each of my motors. If I plug these values into your application, I get extremely accurate predictions on both current draw and prop rpm. This is based on recording data from an eagletree logger both on the ground and in-flight.

I do have one minor issue. It seems that the pitch speed calculation is off if you use a gearbox. For example, if I put the gearbox ratio at 4, the motor speed and prop speed are correct but the pitch speed is low by the multiple of the gearbox. I can just multiply by the gearbox ratio to get the correct value, but I thought you might want to fix it.

Thanks,

Steve

Hi Steve
Thanks for your flowers.
Regarding the pitch speed I have to check ASAP.
It will be fast then to fix the error.
Louis

Hi
Scorpion Calc is up-dated
v3.07 for Metric or Imperial (preferences are saved)
Go to post#1 in this thread
Please destroy older versions (but first ... test the new)
Two bugs fixed
a) Gear Box & pitch speed
b) unit for altitude (m or feet)
Louis

Sorry to intrude but (on 3.07) if I save a file say test.mmc and attempt to reload it I get a data file corrupted message. Worked for me in a prior version.

Clue: Fails if using a custom entry for the motor. Does not fail for Scorpion motors.

Hi
Scorpion Calc is up-dated
v3.08 for Metric or Imperial (preferences are saved in .ini file)
Go to post#1 in this thread for download new release
Please destroy older versions (but first ... test the new)
Save/open bug seems fixed (to be confirmed)
Louis

Save/open works for me here. Thank you Louis!

Next time you have the hood open on the program could the Propeller->Filter entry, in Preferences, be saved as well.

Thanks again...

Hi
Scorpion Calc is up-dated
v3.09 for Metric or Imperial (preferences are saved in .ini file)
Go to post#1 in this thread for download new release
Please destroy older versions (but first ... test the new)
New HK 3026 and HK 4035 Scorpion outrunners
Louis

Hi
Scorpion Calc is up-dated
v3.10 for Metric or Imperial (preferences are saved in .ini file)
Go to post#1 in this thread for download new release
Please destroy older versions (but first ... test the new)
Filter for props (preferences) is now saved
Louis