14T pinion and flight times

[M&P_Hooligan]

Originally Posted by DoubleCH

While going from 14T to 13T is easy, going from 15T to 14T may not be a easy. You'll have to run 4mm shaft adaptor, which means it's thin enough you need to run 3rd bearing support even non-stretch. And then you'll have to be extra careful to align all 3 bearings or else you'll wear out the top bearing in no time. Because of the thin shaft nature, 13/14T pinion runs 2 OWB stacked on top of each other. If 1 OWB doesn't activate for whatever reason the other OWB will wear out the shaft fast although all these wear-out rate may not be as bad if you rub non-stretch and don't fly hard but these are valid concerns. I'm still looking for a cheap 14-pole motor around stock power so that it'll be lower kV but more torque and can run 15T with stretch and have more tooth contact so went wear out teeth as fast. Problem is these motors will be heavier.

Sent from my SGH-I337M using Tapatalk

mine had the adapter and a 13tooth on it with no 3rd bearing support... i went to the adapter with a 15tooth, i see no reason why it is a "Must" have?

[DoubleCH]

Originally Posted by M&P_Hooligan

mine had the adapter and a 13tooth on it with no 3rd bearing support... i went to the adapter with a 15tooth, i see no reason why it is a "Must" have?

If you don't fly hard maybe you can get away with it. I fly 13T hard. I wore out the long shaft faster than I expected, then bought a shaft adapter for the short shaft and wore it out quick also, both from the OWBs from 13T and 14T. I'm now running a custom home-made shaft adapter with seemingly very hard 4mm rod stock to make shaft pieces that I can quite easily replace once worn out. I wore out a few 3rd bearings and my 13T and 14T pinion teeth are quite worn out. I took extra attention to make sure motor is mounted perfectly center (left/right) on the motor mount and make sure motor is mounted perfectly parallel to mainshaft and make sure 3rd bearing is perfectly perpendicular to motor shaft.

[dr dremel]

14T and plastic frame, no 3rd bearing support with long motor shaft (no adapter). I considereded adding the support, but after 80 flights it´s holding up fine so far. Correct belt tension is key to prevent heavy wear.

[DoubleCH]

I'm very conscious of belt tension I'm sure it's not my cause. The stretch nature plus my flying style and setting have quite a lot to do with it. Plus everybody I know of who fly 3D wears out pinion sooner or later so it's not just me. Regarding flying style, I used to run my FBL agility at 110 which makes the 470-blade machine even more responsive than my 450 and my 300X. I used to do the quickest hardest stops on everything from tic-tocs to rainbows to blade-barking bunny hops to punch-outs so much so even when hard-stopping from a full pitch climb the blades would bark loud. And then imagine the hard stops even worse like hitting a brick wall going the other way. I also used to do the quickest stationary aileron tic-tocs so quick you don't hear the blades go "pop, pop, pop, pop" but a constant turbulent sound from the blades hitting their own rotor wash, so much so it would trigger my YGE ESC over-temp if I keep doing it long enough. Plus I used to run governor settings very aggressive to make sure motor never drops rpm below efficient range and bogs. Imagine this, I have a bank for my FBL to fly my strong 3500mAh pack hard down to 3.75V in just 4mins while I usually fly 4-4.5mins with my 2650 packs. I've since been taming down governor aggressiveness, FBL agility, and my flying and will see how things last.

[dr dremel]

Yes I guess the pinion wears just as it´s the case with the Mini Protos (lasting 150-200 flights until sawtooth profile appears), but I don´t have this many flghts on the pinions I used so far. What I noticed on the Mini is that the pinion wears indeed faster when the belt is to loose. Too tight and the upper motor bearing gets punished.

And you may also be correct regarding flying style, I´m more of a smooth flyer with the 2650 packs lasting me 5:30 min.

[DoubleCH]

Just to give you an idea, this is a "tamed-down" version of my "strong pack bank" (vBar's bank) specifically set to run my strong 45C 3500 pack, coming down at 3.75V after 4.5mins of flying.

My Stretched Protos Testing My New Tamed-Down "Strong Pack Bank" (4 min 52 sec)

[banditpowdercoat]

13t and 2600hs!!??? Is that governed or fresh battery non gov hs? No way could I get that from my cc like 100 ESC!!! I am really perplexed as to how some other ESC can get more hs from same motor. Especially if our systems run rpm/volt as the motor ratings state. Being an industrial electrician and working with vfd control all the time. I'm also perplexed by the kv ratings. Because rpm of a elec motor is dictated by the controller output frequency. Not voltage. Voltage equates to how much power the motor has tho. Want faster speed you up the frequency delivered via PWM to the motor. Unless these ESC do not change output frequency just PWM percentage to reduce power via more rotor slip speed?


Sent from my iPhone while my Heli plays with the gophers

[flint723]

Originally Posted by banditpowdercoat

13t and 2600hs!!??? Is that governed or fresh battery non gov hs? No way could I get that from my cc like 100 ESC!!! I am really perplexed as to how some other ESC can get more hs from same motor. Especially if our systems run rpm/volt as the motor ratings state. Being an industrial electrician and working with vfd control all the time. I'm also perplexed by the kv ratings. Because rpm of a elec motor is dictated by the controller output frequency. Not voltage. Voltage equates to how much power the motor has tho. Want faster speed you up the frequency delivered via PWM to the motor. Unless these ESC do not change output frequency just PWM percentage to reduce power via more rotor slip speed?


Sent from my iPhone while my Heli plays with the gophers

I don't know much but I know a couple things. A 3 phase ac motor using a vfd has no permanent magnets.

Our motors use permanent magnets and our escs pulse dc to each phase. They vary the pulse width of each pulse it sends to each phase. And once 100% pulse width is achieved the motor will not spin any faster (at that particular voltage). PWM in our dc brushless motors is only how fast the partial pulse cycles when not at 100% pulse width (100% throttle). So it's something totally different than ac frequency in a vfd.

Of course this is probably an oversimplification since I don't pretend to understand everything going on in a DC brushless esc, especially once there is load applied. If someone else can explain better please don't hesitate to do so.

[DoubleCH]

True, the PWM we mention about our ESCs are for part throttle only. At full throttle, ESC is sending DC to each phase. The key to different ESC yielding different performance may very well be due to phase timing. I'm no expert but from my understanding it's similar to ignition timing to the combustion engine where you can get aggressive on brushless motor timing to squeeze a bit more juice out of it trading in efficiency or perhaps even consistency. Whichever the exact reasoning, in both cases it boils down to dealing with events happening in sine-wave, not like events happening with clear-cut on-off intervals.

[DoubleCH]

13T and 2700 is achievable with no load, 2600 is achievable in-flight but won't be maintained under load. The highest I tried with my stretch and 13T governed is 2500 which started to show insufficient HS headroom. The highest practical I use is 2400 with a strong pack but I normally fly 2250-2350.

[BHChieftain]

I recently stretched my bird and have lowered my HS to around 2400.
That's 70% throttle, 14T, on 465 main blades. I am amazed how much extra flight time I'm getting... I keep adding 15 seconds at a time...

Right now I'm at 6:30 on a 6S 2600mah pack, and I still have a 30% in reserve. Today I'm going to try for 7min... I should still have 20% in reserve if I've done my math right...

Chief

[DoubleCH]

Flying style varies a lot. You'll probably get 8 min flight time with 13T 2400HS base on your 14T result.

[crickr1]

I run 14th , 2600hs, YGE gov store, on my stretched Protos, 465 blades.
4.5- 5min flight time I put 1885 back in my 2600 Desire packs.

[BHChieftain]

Originally Posted by DoubleCH

Flying style varies a lot. You'll probably get 8 min flight time with 13T 2400HS base on your 14T result.

Actually, I was wondering about that-- wouldn't I get *less* runtime with the 13T pinion vs. 14T for the same headspeed since on 13T I'd more RPMs in the motor?

Chief

[dr dremel]

In theory with a higher TC switching losses in the esc should go down. What drives up consumption is load on the motor. Given HS and flying style stays the same, load is the same also, so one should see an improvement with shorter gear ratio.

[DoubleCH]

Load to the motor is less with shorter gearing because of higher mechanical advantage.

[BHChieftain]

Gotcha, thanks!
Chief

[BHChieftain]

I just received a box with a couple of 13T pinions--

I can get to my target headspeed on 14T, but I need to run at 70% throttle and my ESC caps are getting a bit warm-- so I'm planning to run the 13T at the same headspeed but at a higher throttle setting. Trying to determine if I should swap it out now or just wait until the 14T wears out. What's the typical lifespan of the pinion? I have 85 flights on my current one... am I in for a long wait?

Chief

[DoubleCH]

https://www.helifreak.com/showpost.p...6&postcount=15

It also highly depends on your flying style and/or belt tension. If you get 6.5mins out of 2600 pack your pinion may last longer. But in the meantime if you don't fly hard, 13T may not give you a lot more flight time.

[BHChieftain]

Originally Posted by BHChieftain

I recently stretched my bird and have lowered my HS to around 2400.
That's 70% throttle, 14T, on 465 main blades. I am amazed how much extra flight time I'm getting... I keep adding 15 seconds at a time...

Right now I'm at 6:30 on a 6S 2600mah pack, and I still have a 30% in reserve. Today I'm going to try for 7min... I should still have 20% in reserve if I've done my math right...

Chief

I ran about 4 packs at 7min and had exactly 20% reserve, but was doing slow circuit flying (working on my backwards figure 8s). Today I pushed the bird a lot harder and hit LVC just as I was landing, so I think I need to keep it at 6:30...

Chief