Tekno RC Neu or Orig Neu

[George16]

I think I'm going to order 2 2S neuenergy batts and pair each to my 3S for a 5S setup. I like the power of the 6S on 51/20 gearing though :).

[Mozzy]

So, me running my 2700kv on 5s @ 49950rpm is pretty much right on the money.

Also saying that my gear ratios are ok to not overheat the motor. So far it's ok.

Originally Posted by Mozzy

So, me running my 2700kv on 5s @ 49950rpm is pretty much right on the money.

I think that's WAY overkill. I've got a CRT running 4s on a 2200kv and it's ballistically fast. Too much speed and power for the track - big track too. Can't imagine how unholy the speed of a 2700kv on 5s will be...you can't gear low enough...

[Mozzy]

Originally Posted by MacII

I think that's WAY overkill. I've got a CRT running 4s on a 2200kv and it's ballistically fast. Too much speed and power for the track - big track too. Can't imagine how unholy the speed of a 2700kv on 5s will be...you can't gear low enough...

You think so?

I didn't think it was fast enough on 4S & the runtime was way down to what I expected.

For example, I used the 3800 & only got 5.30mins out of it & the 6000 was only 11mins.
I want 5S so I can reduce the power draw with my Tx & increase runtime.

Here's our track, which has only just been finished to race on, but, by no means is the whole area finished.
Still need a drivers stand & it's been put on hold due to Federal Legislation stating that it needs to follow specific guidlines to meet disabled access requirements. So the guy's are working on a design to make it a cheap easy build.

http://rcmadhouse.com/MadForum/viewt...?p=22444#22444

Originally Posted by Mozzy

You think so?

I didn't think it was fast enough on 4S & the runtime was way down to what I expected.

For example, I used the 3800 & only got 5.30mins out of it & the 6000 was only 11mins.
I want 5S so I can reduce the power draw with my Tx & increase runtime.

Here's our track, which has only just been finished to race on, but, by no means is the whole area finished.
Still need a drivers stand & it's been put on hold due to Federal Legislation stating that it needs to follow specific guidlines to meet disabled access requirements. So the guy's are working on a design to make it a cheap easy build.

http://rcmadhouse.com/MadForum/viewt...?p=22444#22444

Originally Posted by MacII

Wow, serious track. I've only had my 1515/1y for one practice and one race weekend. That weekend on a very small and easy track it was drinking about 1800mAh from my 4900 packs to complete a 5 minute race. Not bad considering the motor I replaced was doing the same thing in 2600mAh plus it was WAY faster.

How are you gearing it? I've got mine pegged at 38.75/36.8 according to BG's speedcalc. On the track it feels much faster than the numbers sound. Even at Wolcott, which is a huge track (like yours) it was plenty fast with plenty of go to clear the biggest Quadruple jump I've ever hit.

I have a Jammin CRT with a 1515 1/y that I run on 4s 8000mAh packs and have almost the same results as you. I geared it 14/62 and pulled 1700mAh in 5min. at the Barn.

Mozzy, I think something might be wrong with your setup if your using 3800mAh in 5.30min. And yes, I have more power than I could ever need at the track.

Bye

yes, exactly. i use 4.2V per cell as worst case (highest rpm), as lipos come off the charger at 4.2V per cell.

i never did catch much fish.

[bl-is-future]

yep to get the true MAX rpm you will need to use 4.2v/cell. Any lipo charger will charge the lipos to 4.2v/cell unless you tell it to cut off at less on some chargers.

[VintageMA]

Originally Posted by bl-is-future

yep to get the true MAX rpm you will need to use 4.2v/cell. Any lipo charger will charge the lipos to 4.2v/cell unless you tell it to cut off at less on some chargers.

I wouldn't be concerned with using 4.2 volts/cell in any of your calculations because your cell will never hold that voltage (even fresh off the charger) when you wind that motor up to full speed. Best case you are looking at is 3.7-3.8 for a while and closer to 3.5 (with only the best lipos) when pulling ~20C.

As here is where 2S and 3S setups will have trouble as you'll be pulling big amps and the per cell voltage will be closer to 3.3-3.5v/cell.

I use the nominal 3.7v/cell in all speed calculations for HV. If you are going LV (ie: 2S or 3S) I would recommend using 3.5v.

[George16]

If that's the case, I'm staying with 6S on my 1515 1Y then. Right now, it's geared 51/20 with 43/13 1/8 scale diffs.

[mkrusedc]

Originally Posted by George16

If that's the case, I'm staying with 6S on my 1515 1Y then. Right now, it's geared 51/20 with 43/13 1/8 scale diffs.

I'll be right behind you in a couple of weeks. Sounds perfect to me {insert silly}

[rabosi]

I know you guys don't have the 3905 like I do but there's a chance of extra carnage from your drive line. I've had to replace front center shafts twice running 6s. The second one only lasted about 10 mins. I now have the kershaw front center installed. Hopefully that takes care of it.

[mkrusedc]

Originally Posted by rabosi

I know you guys don't have the 3905 like I do but there's a chance of extra carnage from your drive line. I've had to replace front center shafts twice running 6s. The second one only lasted about 10 mins. I now have the kershaw front center installed. Hopefully that takes care of it.

Thanks for the heads up, but I guess that is "part of the deal".

[George16]

Originally Posted by rabosi

I know you guys don't have the 3905 like I do but there's a chance of extra carnage from your drive line. I've had to replace front center shafts twice running 6s. The second one only lasted about 10 mins. I now have the kershaw front center installed. Hopefully that takes care of it.

Are you running plastic front centers when you broke them? Right now, I'm using a pair of UE titanium center dogbones and UE 8mm cvds on my truck. I also ordered a 108mm steel dogbone from rc alloys as a backup if I break the titanium centers and I also have an extra pair of UE 8mm cvds .

[rabosi]

Originally Posted by George16

Are you running plastic front centers when you broke them? Right now, I'm using a pair of UE titanium center dogbones and UE 8mm cvds on my truck. I also ordered a 108mm steel dogbone from rc alloys as a backup if I break the titanium centers and I also have an extra pair of UE 8mm cvds .

Yep, I was running the 3.3 plastics. First one just stripped, second one sheared at one of the u-joints. They also were very hot to touch at the joints, but don't know why since tranny and diff seem to be turning freely and only fronts have this issue. I already have steel cvds so now with the addition of steel dogbones I'll see if it hold together. Hopefully diffs/tranny hold up

those joints get real hot on my 3905. it's got to be from all the friction when they rotate.