Lehner 1920

[Tom F]

Hmmm...that sounds fantastic - only thing is, is that 4S LiPo is too expensive for me lol

What packs are you using?

I was planning on running 2S for day to day driving to go easy on everything, but 3s for madness

Edit: and what pinions/spurs are you using? i haven't seen 4mm bore 48 pitch?

[Gustav]

It's harder to get a motor that runs good on 2s and 3s than on 3s and 4s because you have a 3rd difference in rpm instead of a quarter.The 1920/7 might be the ticket though,(33k rpm on 2s,and around 50K rpm 3s).That's what Thunderbruiser has chosen to do,i think he has 2s packs already but wants to run 3s aswell.That should do nicely on the track on 2s,it'll run very long runtimes and should run cool,I don't think it'll be blisteringly quick though but probably as much as you can laydown on the track.On 3s it will scream,might get a little hot but should be good for the occasional speed run/bash session,you might have to let it cool every 5 mins or so on 3s though.

Why not use your 5300 on 2s and get a motor specifically for 3s?The 5300 can probably get the best out of a 2s pack anyway.

I'm using the Flightpower evo20 3300 lipos,they're well priced and in the UK.

I have a lathe so i just run a 4mm drill through the 3.17mm(1/8") standard 48p pinions.You need to bore them out on a lathe for them to run true,if you're stuck and don't know anyone else with a lathe then i can help you out,just PM me and you can post me the pinions you want to use(alu. or non-hardened steel would be easier 'till i get my carbide drill bits).4mm is the way to go.

Edit;funnily enough we had almost this exact same discussion earlier todayhttp://www.rc-monster.com/forum/showthread.php?t=3029

[Tom F]

That sounds great...i'm trying to get a powerful motor to run on 2 and 3S because otherwise i have to buy 2, 3, and 4 cell packs (as the 5300 and 6S are to hot to run regularly on 3s, i feel)

I hear what you're saying about the difference though...i like the sound of the 1920/7 - but i'm wary of running a motor with very few turns as i would like some reasonable degree of runtime, lol

What sort of runtimes are you seeing with your set up?

I'm going to email Lehner and ask if they can give me some ballpark figures on the current draw.

I still somewhat favour the 1930 - even though it will be a bit more expensive, it's available in a wider range of winds - however it will be heavy and current thirsty, not to mention the mess it'll make of my diff...gah i don't know

[BrianG]

Originally Posted by Tom F

...I hear what you're saying about the difference though...i like the sound of the 1920/7 - but i'm wary of running a motor with very few turns as i would like some reasonable degree of runtime, lol...

For a given speed, the runtime between a low turn motor (high kv) geared low is VERY close to that of a higher turn motor (lower kv) geared up. The same amount of work is being done so power requirements are about the same.

If I were you, I would choose the motor kv to get around 35k rpm on 2s (4700kv) for the application you see yourself using the most. Then, gear it for the speed you want. For the times you want to "go crazy", you can still run 3s on that motor and still be well within the max rpm specs (52k).

So, if you plan to do more racing and have your 4700kv motor geared for 35mph (typical racing speed), hooking that same motor to 3s with the same gearing will get you right around 50mph give or take.