Logo 690, Motor and pinion question.

Hi all

Im planing to use my Logo 690sx, in a Uvular fuse, for som big air / F3C style of flying.
I have a new Kontronik Pyro 700 450 at home I would love to use..

Im planing to use a 13t pinion,and I fly at 1850 rpm with my jive 120hv esc.

1: Will this motor work for my application, or is it going to be underpowerd, and will it strip gear easy with that, smaller then stock, pinion?

2: Also, im going to use 700mm F3C, heavy ( 240g ) blades, ( I tested other 700mm before on this heli, and it works for my type of flying, using 100mm tailblades ).
Will the heavy blades be safe for the plastic blade grips?

Thanks for helping.

Hi,

regarding the motor, the calculation with a 13t pinion would be good for 2,200 1/min governed, from battery full to empty, but of course you will also be able to run lower head speeds. Depending on the ambient temps, the ESC temperature (hardly any airflow in the fuse) could be an issue. A cooling sink and maybe even a cooling fan on top could be mandatory.
If you don'd do very hard/aggressive load changes I would imagine that the main gear holds up.
Power wise, for big air F3C it should be more than enough, with like 550 W/kg continuous ... we are just spoiled by extreme power ratings nowadays

Regarding the blades, should be no issue, especially with the blade grips with 5 mm bolt—the bolt was more of an issue, not that it would break but that it would bend especially when flying very aggressively (the older 4 mm version).

But we have not tested both ...

Kind regards

Eddi

Born to fly ...
forced to work.



Edited 1 time(s). Last edit at 03/24/2017 08:35AM by Eddi E. aus G..

Eddi E. aus G. Wrote:
-------------------------------------------------------
> Hi,
>
> regarding the motor, the calculation with a 13t
> pinion would be good for 2,200 1/min governed,
> from battery full to empty, but of course you will
> also be able to run lower head speeds. Depending
> on the ambient temps, the ESC temperature (hardly
> any airflow in the fuse) could be an issue. A
> cooling sink and maybe even a cooling fan on top
> could be mandatory.
> If you don'd do very hard/aggressive load changes
> I would imagine that the main gear holds up.
> Power wise, for big air F3C it should be more than
> enough, with like 550 W/kg continuous ... we are
> just spoiled by extreme power ratings nowadays
>
> Regarding the blades, should be no issue,
> especially with the blade grips with 5 mm
> bolt—the bolt was more of an issue, not that it
> would break but that it would bend especially when
> flying very aggressively (the older 4 mm
> version).
>
> But we have not tested both ...
>
> Kind regards
>
> Eddi

Thanks for the reply.

I know that a 12t would be better for my planed RPM range, but is 12t to "stretch it" to much, as far as the "main gear" stripping that could occur with a pinion that small and heavy f3c blades?

Hi,

honestly, I can't positively recommend or recommend against the 12t pinion. On the 600 SX with a 450 kV motor we even use 11t, but of course the 690 with the larger rotor disc and with heavier blades is different.

We found that with what people tend to throw at the 690, the lower kV motor and the larger pinion work good, for a different profile other combinations might also work.

Kind regards

Eddi

Born to fly ...
forced to work.