Kontronik 160 gov 80% throttle a must?

[NickM]

Hi guys please answer this for me. I currently switched motors on my G770 from a 540kv to a 450kv. Both 12s for now, any way can I use 85 or 87% on the Kosmik it will get me close to the desired HS I had with the 540kv and a 20t pinion now I have a 22t and I am 150hS lower so 85 to 87% will be perfect if this will not cause problems. At least for a month or 2 untill I go 14s.

Thanks for help in advance.

P.s. I know he 540 kv is a 700 motor not 770

[Wh1teAfr1can]

you will see poor govenor performance at those percents. the govenor will not have enough head room to hold the headspeed constant unless you are flying very mildly.

[Stolla]

I would run it higher, no problem, as you mention only till you go 14s which is the answer off course. But you may find running it same oercentage lower rpm actually gives you better performance than the higher percentage as rpm will be more consistent

[jhheli]

I have run up to 85% no problem, still won't hurt to just check the logs.

[Wh1teAfr1can]

Originally Posted by jhheli

I have run up to 85% no problem, still won't hurt to just check the logs.

As Justin stated above it can work in some situations but the recommendation is 80% because for most cases it works (ie. gives you a max of 100% pwm under load towards the end of the flight). In some cases with certain motors and heli size relative to motor size, one can run it slightly higher. It is important though to check the logs and make sure the govenor is functioning with enough headroom

[rossk]

+1 for checking logs.

There are several factors that come into play and the 80% is just a guide.
The biggest factor I think is flight style, if you are pushing really hard, you will find that lower than 80% will be needed, on my trex 700 that I am constantly trying to snap in half, 70% is the magic number, PWM just starts touching 100% at the end of the flight, I have high gearing to give me the right HS(2300) at 70%, but If I fly gentle, lower gearing and 80% would be fine.

[NickM]

Ty for the comments, I tried first flight tonight at 85 or 86% can't remember but it was Way better then at 80%. Now as for logs I have no idea how to. When I pull out the ad card and check files is the top one the last flight or the bottom one. Because I would really like to know the flight tonight if it was ok.

Ok also. My 540kv with a 20t pinion produced 1977 HS for 5min flight. I just finished charging battery's and I had 400-450 more MaH left in pacs with the 450kv on a 22tmaking around 1950-1970 HS. Awesome. Now the 540kv was at 80%. He 450kv, last flight I just flew, was at 86% I just check. I can handle the power level it flys at now for 12s if the 86% is ok. Untill 14s is available for me. Lots of money to change.

[jhheli]

Originally Posted by NickM

Ty for the comments, I tried first flight tonight at 85 or 86% can't remember but it was Way better then at 80%. Now as for logs I have no idea how to. When I pull out the ad card and check files is the top one the last flight or the bottom one. Because I would really like to know the flight tonight if it was ok.

Ok also. My 540kv with a 20t pinion produced 1977 HS for 5min flight. I just finished charging battery's and I had 400-450 more MaH left in pacs with the 450kv on a 22tmaking around 1950-1970 HS. Awesome. Now the 540kv was at 80%. He 450kv, last flight I just flew, was at 86% I just check. I can handle the power level it flys at now for 12s if the 86% is ok. Untill 14s is available for me. Lots of money to change.

Glad your happy with it, at the bottom is the new log.

[NickM]

I think I have come to the conclusion that 500kv is the optimal motor for the G770 on 12s. 540kv was nice but bogged, this 450kv is great but I have it on 86% which doesn't big like the 540kv but if I start flying harder I might have problems. Maybe ill try to make a video of me flying and you guys can tell me if I fly easy enough for the 86%. I'm just nervous to do stuff that I'm not supposed to do. 3500-4000 heli hitting ground will suck and ruin my year LOL.

[rossk]

Flying a non optimal setup is not going crash your heli.
If u can't figure out how to read the logs, attach them here and we will see

[jchen]

Hi Guys,

While we're on this topic, if we use 80% as rule of thumb, does it mean
that I'll not be at full throttle if l run say 75% ?

Thanks

[Stolla]

Originally Posted by NickM

I think I have come to the conclusion that 500kv is the optimal motor for the G770 on 12s. 540kv was nice but bogged, this 450kv is great but I have it on 86% which doesn't big like the 540kv but if I start flying harder I might have problems. Maybe ill try to make a video of me flying and you guys can tell me if I fly easy enough for the 86%. I'm just nervous to do stuff that I'm not supposed to do. 3500-4000 heli hitting ground will suck and ruin my year LOL.

All things being equal (same motor) higher kv motor has more power than lower kv so if your 540 bogged and 500 did not, guaranteed you did not have enough headroom on the 540. Its all about your gov setting, if you hit 100% pwm there is nowhere to go for gov to try keep headspeed constant, you will always loose headspeed when load increase as lipos are the bottleneck so its more about keeping headspeed decay to minimum, also weak lipos cannot feed a strong motor so keep in mind the chain is only as strong as its weakest link
This is why logs are so valuable for setup.
Dont worry your machine wont fall out of the sky at higher percentage, tbh your amp draw will be lower at the higher percentage as esc will work less, you will only loose a bit more headspeed under highish loads
@ jchen, even at 80% you are not full throttle, if you were there would be no headroom for the gov, first we have to ask ourselves, what is full throttle?, when you hit 100% pwm your motor is full thr doesnt matter what your curve or percentage reads. In a governed machine unlike a speed setup you are not looking for full thr opening but rather the sweetspot where pwm stays under 100, its not critical as a setup hitting 100% only occasional may perform well.
Gear your heli so you stay under 100% pwm in log at highest percentage thr possible and you will be fine. With kosmik then as close to 80% possible, jive +-65
a hard 3 d pilot may have to go 75 % and larger pinion to be sure at extremes there is enough headroom to stay under 100% pwm, while there would be performance benefit amp draw will be higher etc.

[jchen]

Thanks Stolla

[NTM]

I've found 75 to 78% to be the sweet spot for me with the kosmiks.
80 never seems to be enough regardless of set up.

[Stolla]

Yup as mentioned crazy pilots 75% may be better!

[jchen]

Hi Stolla,

Re your comment about higher kv equals more power.
I would imagine that lower kv of the same motor will
Put out more torque due to more turns of copper wire.
Am I correct to say this ?

[Stolla]

Normally no not really, torque increases with horsepower so the higher kv motor is the stronger motor all things being equal, many manufacturers like scorpion may use less magnets to get higher kv on the same type motor, in such a case the lower kv with more mags will have more torque and possibly power, so when you look at motors be sure you know whats going on inside. My motto is to use the highest kv for your application if power is your sole requirement, lowest kv for your application if flighttimes is your requirement, between the two if you want combination of both. And as mentioned be sure to know the motors use same pole count and mag sizes etc if you are choosing kv only

[jchen]

Thks again Stolla for the tutorial

[NickM]

Ok I ran 4-5 flights with 86% Nope don't do it. Horrible performance. Anddddd I stripped main gear lol. So I like the 540kv scorpion at 80% 1980HS on 12s over the 450kv with a 22t to get same HS at 86%. Gov definitely need the 20% headroom. Reinstalling the 540kv untill I go 14s. Anyone think the Kosmik at86% have anything to do with stripping main gear?

[Wh1teAfr1can]

It shouldn't strip the main gear if anything it would be less aggressive on the gear because it cant make as dramatic a change in power because you will max the pwm out faster. So i would say that it was either too much lash or a weak gear.