3026-1210 kv motor in Trex 500

[kenghock]

I got this motor and want to use in my trex 500.

Could anyone advise what size pinon should I use for basic and later for 3D flying?

The website says I need 8s but I use 6s 2600mAh lipos. Will there be a problem?

Thanks
Ken

[Adrianli]

Do a search for Pinion calculator. Or google it.

U need to determine ur preferred headspeed. I fly my HK500CMT at 2000rpm. It suits my flying. Easy on the motor, esc and batt.

[misato]

Do a search for Pinion calculator. Or google it.

U need to determine ur preferred headspeed. I fly my HK500CMT at 2000rpm. It suits my flying. Easy on the motor, esc and batt.

This formula is based on operating the motor @ 100% throttle to obtain the desired headspeed which is 1/2 of the whole completed picture. For proper governor mode to function, the low load (ie 0 degree pitch) desired headspeed should be somewhere around 75%, so there will be enough room for your setup to react sufficiently to heavily loaded conditions.

[Adrianli]

This formula is based on operating the motor @ 100% throttle to obtain the desired headspeed which is 1/2 of the whole completed picture. For proper governor mode to function, the low load (ie 0 degree pitch) desired headspeed should be somewhere around 75%, so there will be enough room for your setup to react sufficiently to heavily loaded conditions.

U can adjust the efficiency in the formula accordingly. The formula is just a guide for you to obtain the theoritical headspeed so that you can estimate which pinion to purchase.

For true headspeed, u got to mount an optical sensor on ur heli and adjust ur governor accordingly.


W/o the theory formula, u will be clueless to which pinion to use.

[kenghock]

Thanks for the steer guys. I always find there is so much more to learn about this hobby each day.

I just found a similar calc on the scorpion site. At 75% for this motor, I need to use a 17tooth pinon which gives 2100 headspeed. At 100% this becomes 2800rpm.

is this too high? I am a beginner flyer. (actually crasher) What is a safe headspeed range that does not stress things too much?

Thanks
Ken

[misato]

U can adjust the efficiency in the formula accordingly. The formula is just a guide for you to obtain the theoritical headspeed so that you can estimate which pinion to purchase.

For true headspeed, u got to mount an optical sensor on ur heli and adjust ur governor accordingly.


W/o the theory formula, u will be clueless to which pinion to use.

The efficiency in that formula refers to the motor efficiency not the throttle applied. Say in theory, all motor is 100% efficient, so a 1000kv motor will speed true 1000rpm @ 1volt. However, in practical, outrunner typically 75~80% efficient, so the same 1 volt will yield 750~800 rpm effective.

Thus the incomplete formula will need to account for the throttle position in order to be completed. I used the governor guideline of 75% as an example.

so lets assume i need to have target headspeed of 2000 rpm at 100%, (ps.. in your formula... it mentioned 26 teeth pinion? am i reading it wrong or is it wrong?), main gear is 162 teeth. so with voltage at 22.2volt, effective motor rpm is @ 24175.8.

main gear - 162
hspeed - 2000
KV - 1210
volt - 22.2
efficiency - 0.9

motor effectiv rpm - 24175.8
Require pinion ( (hs*maingear)/effective rpm) - 13.40183158

Thus round up is 14 pinion and down is 13 pinion @ 100% throttle position to active 2000rpm.

Lets say i want to achieve a effective 75% power at 2000rpm. The new proposed voltage would need to apply a 0.75 factor to simulate a throttle position @ 75% mark, which gives 16.65volt. so the new proposed pinion would need to be at least 17.86910878 teeth or round up to 18 teeth pinion.

So comparing to your original fomular, which one gives a more practical estimate?

[misato]

Thanks for the steer guys. I always find there is so much more to learn about this hobby each day.

I just found a similar calc on the scorpion site. At 75% for this motor, I need to use a 17tooth pinon which gives 2100 headspeed. At 100% this becomes 2800rpm.

is this too high? I am a beginner flyer. (actually crasher) What is a safe headspeed range that does not stress things too much?

Thanks
Ken

For a Trex500, 2800 headspeed is actually still in a good range for 3D. I keep mine at between 2200 ~ 2500 max for sports flying to save power for longer flight time.

[kenghock]

Thanks guys.

[JYZoom]

Ken,
If I am not wrong this is an FBL heli
Then whatever calculator you use it is primary for flybar heli.
You need to estimate the calculated output compare to real FBL is a 10% higher headspeed.
SO be careful...I suggest you drop to 16th teeth instead of 17....may be even 15.

Jonathan

[Niven]

U can adjust the efficiency in the formula accordingly. The formula is just a guide for you to obtain the theoritical headspeed so that you can estimate which pinion to purchase.

For true headspeed, u got to mount an optical sensor on ur heli and adjust ur governor accordingly.


W/o the theory formula, u will be clueless to which pinion to use.

sorry for OT...
congrats on 8888 posts bro...
tml wednesday... can huat chai...
tml 4D gt kang tao boh??... hahax....

[Adrianli]

Morning.

The efficiency in that formula refers to the motor efficiency not the throttle applied. Say in theory, all motor is 100% efficient, so a 1000kv motor will speed true 1000rpm @ 1volt. However, in practical, outrunner typically 75~80% efficient, so the same 1 volt will yield 750~800 rpm effective.

I adjust the efficiency cell to see how much throttle I need to input to get the correct headspeed. I usually fly at 3/4 throttle for hovering, so I adjust the efficiency to 0.75. It is up to TS to interpret the results I posted from my calculation. The glass can be half full or half empty. I see the calculation as the motor is not sufficient to sustain a headspeed of 2000rpm cos the pinion indicated does not exist for trex500 heli.

Thus the incomplete formula will need to account for the throttle position in order to be completed. I used the governor guideline of 75% as an example.

so lets assume i need to have target headspeed of 2000 rpm at 100%, (ps.. in your formula... it mentioned 26 teeth pinion? am i reading it wrong or is it wrong?), main gear is 162 teeth. so with voltage at 22.2volt, effective motor rpm is @ 24175.8.

main gear - 162
hspeed - 2000
KV - 1210
volt - 22.2
efficiency - 0.9

motor effectiv rpm - 24175.8
Require pinion ( (hs*maingear)/effective rpm) - 13.40183158

Thus round up is 14 pinion and down is 13 pinion @ 100% throttle position to active 2000rpm.

Lets say i want to achieve a effective 75% power at 2000rpm. The new proposed voltage would need to apply a 0.75 factor to simulate a throttle position @ 75% mark, which gives 16.65volt. so the new proposed pinion would need to be at least 17.86910878 teeth or round up to 18 teeth pinion.

So comparing to your original fomular, which one gives a more practical estimate?

There is a flaw in ur calculation. TS already stated he will be using a 6S lipo. Max charge is 25.2V @4.2V per cell. The norminal voltage for lipo is 3.7V per cell, thus giving a total voltage of a 6S lipo of 22.2V. The lowest a lipo should be discharged b4 it gets damnaged is 3.3V per cell, thus a total of 19.8V. I would not encourage that kind of abuse to the lipo, normally I fly till 3.5V per cell under load.

A voltage of 16.65V will see an exploding lipo!!! Please re-do ur calculations.

I am not entirely electrical or electronics trained but during myourse of work previously, I am to use theoritical calculations to solve problems b4 practical work is carried out. Example, the owner buys a 200Ton shackle, he wants to know his existing tow pin is able to take the load of 200Ton SWL. We dont go out and get a 200Ton crane or load to do such testing!!! It will cost thousands of dollars. We use hydraulic pressure to mimic the 200Ton strain on the tow pin before issuing a cert and countersigned by the surveyor. We will do theoritical calculation first, then get the suitable pressure gauge and hydraulic pump. And this all has to be done within 1-2hrs. Customer happy, we happy and get paid. Welcome to the life of an operations engineer in a shipyard.

Ok, no more OT from me. Thatz all, up to TS to select his suitable pinion for his desired headspeed.

[Adrianli]

sorry for OT...
congrats on 8888 posts bro...
tml wednesday... can huat chai...
tml 4D gt kang tao boh??... hahax....

Hi, long time no see!!!

Thks, but I am not counting my posts. I didnt even realised I posted so much already!!!

I think admin will me for so many postings. Will cut down on my posting. One post per day only???

[Adrianli]

Thanks for the steer guys. I always find there is so much more to learn about this hobby each day.

I just found a similar calc on the scorpion site. At 75% for this motor, I need to use a 17tooth pinon which gives 2100 headspeed. At 100% this becomes 2800rpm.

is this too high? I am a beginner flyer. (actually crasher) What is a safe headspeed range that does not stress things too much?

Thanks
Ken

Really wana you. I would like to introduce you to a very good guide that you should already have.

That is the MANUAL !!!


Go n have a look at ur Trex500 manual for safe headspeed for beginner. OMG, not sure if u ever read the manual. I fly a HK500CMT which does not have a manual but I use the Trex500 settings as a guide. BTW, mine is on 4S lipo, 17T pinion, 1800kv motor and achieving a headspeed of 2000rpm on 70% throttle.

Please read the manual accordingly. No more posting from me here. Given u the guides, u have to make ur own choices.

[kenghock]

Opps. Didn't see that page. I'll take a look there.
Ken