10s or 12s with Pyro 650-62L

[sj257]

Having just looked the motor up, I notice that both 10s and 12s would potentially exceed the max RPM on the Kontronics web site.

What was their comment on revs when you asked them?

Sorry. I probably should have looked at this before singing the praises of a 12s set up.

sj

[Si Goodchild]

Not withstanding the above comment, my calcs are as follows:620Kv * 0.8 (efficiency) * 3.7v * 12cells * 12 teeth / 129 teeth = 2050 rpm. Sounds sensible for 600mm blades to me.

[sj257]

Si, you might be spot on there. Does the efficiency actually reduce the revs, or it it an efficiency loss of work in to work out requiring more amps?

If it's lost amps wouldn't it be a bit different?

My logging has shown 48v maintained from 12s, so I went 48v x 620 kv = 29,760 rpm. Web site I saw said 25,000 max rpm for the motor. Carried through. (29,760 rpm x 12 teeth)/129 teeth = 2,768 as a 100% head speed. Possibly higher or lower depending on the voltage say of the pack under load.

At the end of a flight my packs typically show 45-46v. 45.5x620 = 28,210, so at zero pitch still likely to over speed the motor. I'm typically draining my packs at an average of 6.4c so the voltage say is provavly pretty low unless you really load up the head.

I guess if you use a govenor mode with a max head speed of 2,325 (sounds nice) on a 12t pinion you stay within the motors capacity.

If you're happy to fly in govenor mode then this looks good, and 12s will still give you the benefits of low current draw, low heat etc.

sj

[Martyn (Bomber)]

The 700 series Pyro motors (450kv/520kv) show 25,000 rpm max (3kw cont/5kw peak) and are stated as 12s motors, then the 650 series Pyro motors (620kv/650kv) show 25,000 rpm max (3kw cont/4.5kw peak) and are stated as 10s motors so they must be good for the higher voltages, I always use the Jive governor on my heli's at 80% or less anyway so that should be ok, what do you think ???

[sj257]

To be honest Martyn I don't know enough about motor efficiencies to know the impact, in this case.

The 700 motor looks ideal, but that isn't what you have.

To my limited knowledge you still look good to go on the 650-62. Should give you a nice governed head speed. :-)

I guess what we don't know is the efficiency of the motor on 12s. But if flights are shorter, they'll probably also be more fun.

Would be good to catch up with you once it's together to see how it goes.

sj

[Martyn (Bomber)]

To be honest Martyn I don't know enough about motor efficiencies to know the impact, in this case.

The 700 motor looks ideal, but that isn't what you have.

To my limited knowledge you still look good to go on the 650-62. Should give you a nice governed head speed. :-)

I guess what we don't know is the efficiency of the motor on 12s. But if flights are shorter, they'll probably also be more fun.

Would be good to catch up with you once it's together to see how it goes.

sj

Yeah for sure, that would be good

Thanks for the advice everyone, I've put a post out on the Freak to see what they say about it too

[stanley1]

Hey martyn id say that 80% is quite high for the jive. You need more of a headroom for the govener to function properly really. 60% max is best and then just use the correct pinion to acheive the headspeed you want

[Martyn (Bomber)]

Hey martyn id say that 80% is quite high for the jive. You need more of a headroom for the govener to function properly really. 60% max is best and then just use the correct pinion to acheive the headspeed you want

I think I've read the Jive should be run at 80% max in governor but my Fusion 6s was running at 65% to get 2150rpm which like you say gives you a good bit of headroom.

[Ross Northcott]

Hey martyn id say that 80% is quite high for the jive. You need more of a headroom for the govener to function properly really. 60% max is best and then just use the correct pinion to acheive the headspeed you want

WRONG, 80% is near on perfect for the jive, 75% is bang on perfect imo, my helijive would cut out on me at 64% as over current flashing lights, moved down a pinion and upped the TC to 83% and is now perfect, to low a TC and the esc can overheat, the higher the curve the cooler it runs.

[stanley1]

Ive heard that According to several j-log files anything over 60% is not allowing enough of a headroom.
Obviously it would run with better efficency and cooler with higher of a %.
with the heatsink installed mine comes down warmish and I run at 60%. Id rather a better performing heli and if it costs me effecientcy then so be it

[stanley1]

double post sorry

[Martyn (Bomber)]

I agree with Stan as on the Freak everyone including some pros (Bert Kammerer, Leon Luke) seem to think that 60% is the sweet spot for the Jive governor

[Ross Northcott]

I agree with Stan as on the Freak everyone including some pros (Bert Kammerer, Leon Luke) seem to think that 60% is the sweet spot for the Jive governor

Well good luck with what you choose but i have used kontronik for a while now and use 5 of them on different heli's, tried them all on different TC's, and on all my jives i found around the 75% is best results, and believe me i have tried most percentages and different pinions on all of them.

[stanley1]

each to their own and what ever works best for you then great

[Martyn (Bomber)]

Fair enough gashead and thanks for the input

Is the Jive 80+HV ok for a 10s setup or does it need to be the Power Jive/Heli Jive ???