425 gearing question

[belcom]

I want to put together a 425 basic out of parts I have accumulated for a trainer that is cheap to fix. And since I will be upgarding my exi 500 to Compass Atom 500 I will have a Hyperion motor left over that I want to use in the Gaui. It is the same motor as Scorpion 1600kv.

So my question is what is the best gearing for efficiency and does it come with the kit or I have to order extra gears as well? I ended up with an extra ICE 100 esc so will be using it in governor mode most likely. Looking to get the headspeed to around 2600-2800 maybe a bit higher. I have seen the calculator but I am not sure what is stock and what needs to be ordered and also I saw that there are different combinations I could use. I need some advice from somebody who has done it and it worked well for them. Thanks.

[arturoo1977]

Hi, stock kit comes with:

50T From main gear
19T One way gear
61T Rear main gear

According to calculator, if you use a 13T pinion, will get 2870 rpm of head speed. Running on 6S.

Greetings

[Dracx]

I've got the ICE100 running "Set RPM" at 2600 and am using the Hyperion 35C 2200mAh battery. I started with the Scorpion 1400kv, stock gearing and a 15T pinion. During moderate 3D (flips, rolls, hard turns) the motor bogged down and the ICE reported a lot of 100% motor output during thos hard maneuvers. Motor temp came down at 130F and battery temp at 110F.

Reading the ICE documentation they recommend that, if using any Govenor Modes, your target head speed should run at 80% - 85% motor output. So, I upgraded to the Scorpion 1600kv and a 20T one-way gear, keeping the remaining gears stock. Reprogramming the ICE for the new gear ratio, that puts me at 82.6% motor output. In flight, I have to try very hard (like a panic recovery) to hit 100% motor output, usually averaging <90%. The motor temp comes down at 87F and batteries at 95F.

Now, keep in mind that I fly in Colorado. The air is thin at 5200 feet above sea-level and there is very, very little humidity. This provides much different flight characteristics than locations near sea-level, where motors don't have to work nearly as hard. Also, it's winter here so I am flying in ambient temps of 20F - 45F. Temps will likely run higher in the summer when temps get 90F+. Fortunately, the Scorpion motors are rated up to 356F, so there shouldn't be a problem.

[belcom]

but would it be more eficient running a 60T main gear with a 16T pinion for example. This is what I am wondering. I want to set it up and make sure everything stays nice and cool however with plenty of power to throw it around. they provide these gear options but I can't find an explanation what is best in which case.

[nexgen]

More tooth engagement is better IMO. Also the larger front gear will dissipate heat better

Rooted MT3G + Cyanogen Mod 6.1 + Tapatalk = WIN

[Dracx]

Setting your gear ratio too high or too low is equally bad. Unfortunately, I can't find any documentation showing the optimal power band for the Scorpion motors. That would tell you what the best gear ratio is.

In any case, I can only offer my experience with the two motors and gear ratios I presented. I'm loving my 1600kv and the setup is very successful.

[fusionsx00]

So stock gearing 13t pinion, 1400kv motor is 2870???
I must have done something wrong, I figured I needed a 14t pinion to reach 2800
which is my target, at 85%.

[nexgen]

At nominal voltage, 22.2v, with a 1400kv motor the 13t will give you around 2300 rpm based on 95% efficiency which IMO is a little generous. Regarding governing, you want to govern/gear your bird to be able to achieve the headspeed you are looking for at the end of the pack, this way the gov will not be hitting 100% throttle output except occasionally right at the end of the flight. If you want, say 2800 rpm the whole flight, on that motor and a stock 50/19/61 setup, you would want to run a 16t pinion. This will give you a 10.03:1 gear ratio and should be fairly efficient with a high kv setup. You could also run a 19t pinion and a 60t front gear and get roughly the same headspeed and gear ratio of 10.17:1 but also have the advantage of more tooth engagement in that area.

Use the headspeed calculator located in the *LOOK HERE* thread in the 550 section as it is very accurate.
Expanded 425/550 HS calculator

And here is a link to the larger pinions if you are interested.
Robinson Racing 0.8M Pinions 12t-25t



Rooted MT3G + Cyanogen Mod 6.1 + Tapatalk = WIN

[fusionsx00]

Hmm, im kinda intrested in the larger pinion setup

[nexgen]

I used to melt the smaller ones (42 and 50 with a 16t) on hard punchouts and extended load maneuvers. Now I run 24t/60/20/61 with my 4020-910 at 7.63:1 ratio, running 500mm blades at 2400 governed. It is the lowest gear ratio/ highest consistent hs setup I have run, the motor pulls HARD and the gears don't even break a sweat, hehe.

Rooted MT3G + Cyanogen Mod 6.1 + Tapatalk = WIN

[fusionsx00]

Ill probably get that setup when I get a scorpion motor
Unless the 504 starts chewing gears

[fusionsx00]

I just got my 16t pinion, installed motor .
if all goes well, I will be testing tonight.
I spooled up without blades and man the gear train is noisy as hell.

It is smooth as can be, I set my torque tube gear mesh to about .004 clearance
with a gauge pin and it spins freely,

I will post a video soon, hope my one way gear will last at least for hovering.
vxb on the way

[fusionsx00]

Well I got the heli up, and somewhere I messed up, she is fine
Show room ready brand new condition, but the head speed seems way fast
I set up with the stock gearing and a 16t pinion, gov mode set up with a castle link
all motor info input, and gear ratio inputed. It gave me these settings
30% idle 1(2600rpm) 60% idle 2(2700rpm) and idle 3 85% 2750
Any higher said was too high, I put in 10.03:1 ratio
I got into idle 1, and it was fine but idle 2 was insane, nothing seemed wrong with the heli
just seemed way too fast, I think im gona have to run the 15t pinion same settings and see if it feels better

Ohh yeah nexgen your a madman, no bar is insane, it is more resposive than my 200 fb gaui, high rates. I about flipped her over with barley any stick input, the sk720 is in now
just have to go back thru the setup, crazy I tell ya, I don't have the nerve or quickness for that.

[nexgen]

Originally Posted by fusionsx00

<snip> nexgen your a madman, <snip>

yeah, thats what they tell me, hehe

run the HS calc against the 15t pinion to get the exact gear ratio, and maybe drop 100ish or so RPM,s off each box in the castle link and you shoudl be good to go

[fusionsx00]

It takes a very skilled pilot with nerves of steel to run no-bar, I can say that from first hand experience.
Maybee in a few years ill try again

My pinion will be in Tuesday, ill let you know how it goes

[fusionsx00]

Ok, I switched to a 15t pinion and got a new 20t oneway gear
I ran the calculator and it said 9.xx, seems alot better now

Another thing is my cc ice 75 is peaking at 75amps
isn't this motor ran on a 60 amp?
its not getting hot, but im kinda worried about that
maybe in the summer it will be a issue, right now its 40 degrees:0

[Mikej]

Originally Posted by fusionsx00

Ok, I switched to a 15t pinion and got a new 20t oneway gear
I ran the calculator and it said 9.xx, seems alot better now

Another thing is my cc ice 75 is peaking at 75amps
isn't this motor ran on a 60 amp?
its not getting hot, but im kinda worried about that
maybe in the summer it will be a issue, right now its 40 degrees:0

ESC ratings are generally continuous and the peak will be higher (something like 60 amps continuous, with a peak (of usually around 15 seconds) of 75amps), so you should be fine on a 60 amp so long as the continuous is 60a and teh peak of 75a is 15 seconds or less.

I found that my Hurri was harder on it's batteries when I had it set up as a 425 than it is as a 500 or 550 I guess it's the HS

[fusionsx00]

Im running a cc ice 75
, I just thought that the motor would be around 60 amps continuous

I think the ice 75 can peak at 90amps , so it should be fine

[Jerrymac]

Originally Posted by Mikej

I found that my Hurri was harder on it's batteries when I had it set up as a 425 than it is as a 500 or 550 I guess it's the HS

I would have to agree Mike. My 425 runs a head speed of around 2900 to 3000 (calculated) and I barely get 4:00 with 2500mah batteries. My 550 runs 550mm blades and a head speed of around 1900 and I can easily get 8 min. with 3300mah batteries.

[fusionsx00]

5:50 min on 2950's. that leaves about 26% in the pack

im getting a scorpion soon, im going with a higher kv motor, that way i can run my head speed and run closer to the motors optimum efficency