Please Check/Confirm My Electric Setups

[StreetDragster]

Hi All,



Fairly New to electrics, I’m trying to calculate if I have the optimal gear ratio for my heli’s for my sport flying (Stall turns, loops, flips and rolls at the moment) to try and maximise flight times without too much of a degrade in power



I’ve done some calculations from various sources about the web, could someone please check them over for me and see if I’ve made any glaring errors or false assumptions.



Main assumptions are-

Battery Voltage Fully Charged = 4.2v per cell x number of cells (I.e 6s = 25.2v)

Battery Voltage Discharged = Following the 80% rule, I calculated it as follows for 6S

25.2 fully charged

22.2 fully discharged

3v between fully charged and discharged

80% of 3v is 2.4v

25.2v minus 2.4v = 22.8v @ 80% discharge

Efficiency = I did all calculations assuming 100% efficiency, and then at the end, reduced everything to 90% to allow for losses.







Batteries are Turnigy 30C 6s 4000mAh packs, either in 6S on the 550E or 12S on the ENV



550E V2

Align 600mx 1220kv 6 pole motor

Helical Geared with 11T standard pinion

YGE 120LV ESC

Auto Timing

12KHz PWM frequency

Castle BEC at 6v running the servos

2300rpm head speed stunt 2

Align 520mm FBL Blades

13 Degrees Pitch



Rave ENV

Scorpion HK3-4035-560 560kv 10 pole motor

Straight Geared with 11T Scorpion pinion (12T in my flight box)

YGE 120HV ESC

Auto Timing

12KHZ PWM Frequency

Power and Controls are completely separate electrically

2000rpm head speed stunt 2

Edge 713mm FBL Blades

13 Degrees Pitch



Thanks in advance for all help, and especially any recommendations for improvements.



Matt

[BenjaminKenobi]

Hi,

Everything looks great! Regarding the 20% rule, it's 20% of the MAH of the lipo, not the voltage. So for a 2200mah lipo you would put back in roughly 1700mah. This of course can only be accurately measured on a charger so the voltage at the field would be a good guideline as you have stated. It takes a couple of sessions to accurately determine your timer settings.

Cool?

[StreetDragster]

Hi,

Everything looks great! Regarding the 20% rule, it's 20% of the MAH of the lipo, not the voltage. So for a 2200mah lipo you would put back in roughly 1700mah. This of course can only be accurately measured on a charger so the voltage at the field would be a good guideline as you have stated. It takes a couple of sessions to accurately determine your timer settings.

Cool?

Great, thats reassuring, although it seems that the original post missed out the table i wanted to insert so i've put that back in.

Given the above, would you run the ENV on the 11T or the 12T pinion? Its on the 11T at the moment.

Thanks

Matt

[AcidDrink]

It's really pretty simple, you want about 10:1 gear ratio at your target headspeed for best efficiency. The explanation is long and boring

Your calculations look good to me.