Mini P FBL stretch 4s build thread

[scott s]

well guy's the 15 tooth pinion on 6s with 1300 kv motor yields a better gear ratio for those who want lower head speeds swinginging 350 blades than the 4s with 2010 kv motor does with the 14 tooth. I am going 6s with hyperion 1100mah 45c batteries. I will keep in touch on results. I will avoid the 14 tooth pinion like the plaque and if happy up to a 16 on 6s. I am sticking with the cc lite 50 esc. Just after a lot of research I have determined that it is way easier to set up even if I have to tweak the governor parameters in the cc software a bit. Dont have to go thru all the taching with blades on and find the correct throttle endpoints for the headspeed I want. Just easier getting desired headspeed without a bunch of fuss.

[Thunder Fighter]

I think 3s on a stretch is going to be hard on the packs and heat up the ESC more but it depends on what flying style and headspeed you are after. 4s works very well with the stretch and gives good performance without needing 65C packs.

It is normal to run a lower headspeed with the bigger blades and you will get the same pop, but the amp draw may be higher even with the reduced headspeed.

I wouldn't use the 14 tooth but the 15 tooth with the 4s motor should work well, I still haven't fitted mine and have the 16 tooth on the 4s motor with a lower throttle curve to keep the headspeed down.

//Dennis.

[scott s]

umm I said 6 series batteries on the 1300 kv motor. 1100mah hyperions 45c discharge rate. just a couple grams heavier than your every day 3s 2200mah. AGAIN the 6s 1300kv motor gives a better gear ratio with not having to go or even try the 14 tooth pinion. The 4s motor from msh should have been about an 1800kv or so(off the top of my head) to avoid the thin wall small pinion. This is what happens when rebadged stuff is used and not purpose built.I am not gonna swing 350 blades at 3200 plus head speed. I am not that good at smack down and prefer big air and flight time!

[baui2000]

I fly stretch on 15T, 2200mAh 40C 4S packs without a problem. Over 5 minutes of sport flying / mild 3D, a bit less if when throw it around harder.
Tached the setup yesterday. 2750RPM on 65% and 3100RPM on 75% in gov store mode. It feels a lot better than the 14T before, because it gives to governor more space to breathe.

[Thunder Fighter]

Originally Posted by scott s

umm I said 6 series batteries on the 1300 kv motor.

I was responding to the question asked in the post before yours, I think we replied at about the same time.

This is what happens when rebadged stuff is used and not purpose built.

Do you mean the 4s motor? I think Corrado would have tested the 1630KV Scorpion on 4s and decided it wasn't enough so the 2010KV was his next choice. I thought it was going to be too high but have been running on the 16 tooth pinion with 350 blades and 4s since my 14 tooth broke. The ESC is not even getting even warm at about 65-85% in Governor Store mode I have been running. So the 15 tooth looks fine in practice for the 4s motor with 4s pack and the YGE for sports flying 2500-3000 rpm.

I'm not saying the 6s is not a good solution though, it is just as valid if not more so if you are going to do hard 3d. I choose 4s as it was easier to find packs around the right size from many sources.

//Dennis.

[9sec240]

Thanks for the input guys. I ordered the stretch kit and 15T pinion.

[hakiem]

do you guys have any opinion using a 16th pinion with 2010kv motor ? or should i use 15th pinion with 2010kv ? whats the different would i expect from these 2 ?

[baui2000]

Given that 15T on 2010kV motor and 4S will get you close to or a bit above 4000 RPM @ 100% throttle, 16T would yield insane headspeeds. I'd be scared to death that 350mm blades will rip the head apart.

[hakiem]

lol. well i have been using the 16th with my 2010kv for quite sometime now.
so what is the recommended pinion to use for the 2010kv ? I'm a bit lost now. I have been flying with a 16th pinion for quite some time now. headspeed around 2500. if i use 15th pinion with the same headspeed, does it perform better ?

[baui2000]

You fly 4S, right? What throttle percentage do you get that 2500 rpm with?

I've been flying 2010kV with 15T. Tached 2750rpm @ 65% and 3100rpm @ 75% throttle in gov store, 4S 40C packs. These percentages still give the governor a lot of headroom.
You should get better results on 2500 because of the better gear ratio for that HS (better throttle resolution if you want).

[hakiem]

yes. i'm currently using 4s setup 45c.

I have never tached my headspeed. All i do was calculate the old school style.lol

2010kv x 16.8 (4s) = 33768v

33768v / 7.5 (120 gear x 16th) = 4502rpm

4502 x 90% = 4052 max at 100% full throttle

at 60% = 2431rpm

at 65% = 2633rpm

so currently i'm flying with 63% which should result in between those 2.

is this correct ?

[baui2000]

Well, I'm not so sure about that The math is right, but as I said, I tached mine and got 2750 on 65% with 15T pinion.

Edit: This is what readyheli simple math calculator says about my setup (quite far from reality if you ask me)

4S/40C, 120/15 gear ratio, governor on, 90% efficiency

Throttle 60%: 3095
Throttle 65%: 3192
Throttle 70%: 3289
Throttle 75%: 3385
Throttle 80%: 3482
Throttle 85%: 3579
Throttle 90%: 3676
Throttle 90%: 3772

[hakiem]

ahh. looks like i need to get myself a tachometer then. that's when I know if my calculation is correct on not.sighh.

[Thunder Fighter]

Like I said above, the 16 tooth will work with the 4s motor on 4s packs but it runs lower on the ESC's throttle curve. With the YGE ESC and active freewheel it works but is not as efficient as the 15 tooth. With another ESC (other than Kontronik) you may find that it will cause the ESC to get very hot running at the low percentage throttle required with the 16 tooth and may not be optimum even with the 15 tooth if you want to use lower headspeed.

//Dennis.

[hakiem]

thanks for your feedback. how about if i run a much higher headspeed. let say around 2800rpm or maybe 3000rpm. which pinion would be optimum for that usage ? I might consider changing my headspeed as long as it performs at it's optimum level.

[macem]

... 3000 rpm, thats the deepest level of the minips natural biotop ...



macem

[baui2000]

3100 or so gives you the same blade tip speed on 350mm blades as 3500 with 325mm if i remember right

[hakiem]

Originally Posted by baui2000

3100 or so gives you the same blade tip speed on 350mm blades as 3500 with 325mm if i remember right

so are you saying it's better to avoid 3000rpm with my current setup ?

[hakiem]

Originally Posted by macem

... 3000 rpm, thats the deepest level of the minips natural biotop ...



macem

you are as crazy as Dario...(in a good way i mean)

[macem]

... i am far away from that guys (not only concerning the flying skills... )

i guess, dario reaches 4000 rpm, luigi rungi (msh team pilot) posted something about 3750 rpm when presenting the miniprotos one year ago at te verona model expo...

YouTube

YouTube

so mine 3000rpms are not more than kindergarden-style - but more then enough for me ...

macem

i agree, that the stretchversion should be flown a little bit more andante ...