Is this possible?! - RC-Monster Forums

suicideneil · 06:17 PM

http://www.youtube.com/watch?v=tkm3w-Z-Nmg

An E-Revo running the MM and 8XL.... and 14cells. And it didnt blow up, just goes like stink! Who is Dafinn1- is that someone on this forum?....

EDIT: Finnster! How does it cope on 14cells man, thats pushing the MM abit isnt it?

jnev · 05.27.2007, 06:29 PM

That should be fine. I am assuming he is running an external bec. This is a very popular set up for not very much. There are people that have even run this set up, up to 5s, although ti isn't recommended. Normally 4s is used with this set up.

suicideneil · 05.27.2007, 06:34 PM

Fair enough- I knew a few people were running 4s which is 14.8v (I think), so thats do-able on a 12 cells esc, but I didnt realise it would take 14cells so well. I guess this is yet more food for thought....... my poor brain.....

crazyjr · 05.27.2007, 07:57 PM

I have, but have run into problems with heat (I live in georgia USA and its hot already and getting hotter) I haven't tryed fans yet but i'm thinking if not runing my stuff till a MMM or Tekin r1mt

05.27.2007, 08:20 PM

I built my Revo around a MM, a 9XL motor and 14 cells. I have two sets of IB4200s. I do use an external UBEC, but it handles the 14 subCs like a charm.

05.28.2007, 12:43 AM

Some Mamba Max controllers will handle more than others. Of the five that I have, two of them will do 5S and all will do 4S lipo. I run an 8XL and 9XL in my 8ight T on 4S and 5S lipo and it is just fine...and yes, it is wicked on the track.

crazyjr · 05.28.2007, 02:35 AM

Quote:

Originally Posted by AAngel

Some Mamba Max controllers will handle more than others. Of the five that I have, two of them will do 5S and all will do 4S lipo. I run an 8XL and 9XL in my 8ight T on 4S and 5S lipo and it is just fine...and yes, it is wicked on the track.

5s on a 9XL will stand the hair on the back of you're neck up won't it:027:

05.28.2007, 02:46 AM

The 9XL on 5S actually scared me. At first I didn't want to run it because I was feeling like something just had to break. There was just too much power. Blipping the throttle a bit too hard resulted in my truck being on its lid. I really feel that it could have done a standing back flip if I had tried.

Make no mistake that putting things down on paper does not equal what happens in real life. On paper, the 9XL on 5S should have been the equivalent of a 7XL on 4S, but that wasn't the case. In the case of the Feigao motors, adding voltage also ups the torque. I just couldn't drive it on the track, no matter how much I geared down or up. Needless to say, I went back to 4S.

It was a hoot though, and good from dropping jaws. I still keep the 5S pack in my field box for times when I just want to make the nitro guys really nervous.

suicideneil · 05.28.2007, 05:56 PM

Cajun- that Revo of yours weighs 10.5lbs correct? What do you gear it at overall?

If I am correct then:-

12cells = 14.4v vs 4s =14.8v
14cells = 16.8v vs 5s = 18.5v

Since the MM is ment for 12cells I can see why some dont like 5s, so In my case (no lipos), 14cells (good cells that is) would be a good substitute. Yet more food for thought; Im going to get fat at this rate....

05.28.2007, 09:27 PM

Quote:

Originally Posted by suicideneil

Cajun- that Revo of yours weighs 10.5lbs correct? What do you gear it at overall?

Yep, that's about right, maybe a little more. The only scale I've had to use is an old one I found in the shed that would melt if you sprayed it down with WD40, so I'm betting it's not completely accurate.

I have it at 18/38 right now and can run without the fans. I tried the 20/36 set up I have on hand but it seemed to get a little hotter so I went back to the 18/38. I"ll eventually get the fans fitted so I can gear a little higher, the 20/36 was INSANE for the couple of battery packs I ran it.

crazyjr · 05.28.2007, 11:35 PM

My revo with 5s 8000 mah is almost 11 pounds

05.29.2007, 01:15 AM

I didn't think that the Revos were that heavy. My 8ight with the same setup weighs less than that.

07:54 AM

It turned out heavier than I thought, and I'm going to try to shave a little weight, but I don't think I can get rid of much. I need to do the single steering servo and some speed holes in the aluminum. The battery pack weighs a lot, so I'm hoping a switch to lipo will reduce some weight too, but the budget isn't going to allow that for a while. I"m not sure where else I can cut anything, the tranny is basically a stick and a gear, I stripped all the brake stuff. The only aluminum I have it is the main chassis.

Finnster · 05.29.2007, 09:53 AM

Hey man, nice vid :) If you like that one, click the one in my sig. That's on 5S, and its faster than Jesus. Too fast really for most things. I mostly drive on 4S now.

The ESC does well on 14 cells. I've ran 16cells, then later 5S, and even that was ok, but 5S is a bit nutty. Really the larger challenge has been keeping the motor cool vs the ESC.

My v1 ( 2.5 w/ Emaxx tranny, as shown in vids) weighed 4.3kg (9.5 lbs) w/o batts. My v2 (3.3 chassis, revo tranny, man brakes) weighs 4.2KG (9.25 lbs) w/o batts. These are stock otherwise, inc talons. I do have some Ti parts and red rods coming in, so this will drop a bit more on v2, but only so much. As cajun said, there is not a whole lot else to trim. Slayden (TRX) races his 3.3 @ 9.5 lbs RTR, so I wouldn't expect to cut too much. If the TRX team can win championships at that weight, its prolly fine IMO. :)

The biggest weight diff in RTR will be the batts. High end lipos weigh as little as ~450g for a 4S ~5000 mah. My TrueRCs weigh more, 4S 6400 is ~700+g, while the 5S 8000 mah tops 900+g. The huge power and TQ of BL makes up for the slighly heavier weight IMO.

Lastly, My FDR is ~16.2:1 +/- .3. Generally on v1 I run 15/51. V2 is a little higher at 16.3, but I'm still playing with the gearing.

suicideneil · 06:28 PM

Hmm, I think the only possible way to make my truck lighter would be to either tie helium balloons to it, or buy CF parts perhaps, but neither is a realistic option. Perhaps doing the "single speed gearbox chop in half with G1 conversion" would help, and single stronger servo too. I have my Roadrages now so I will do a test tomorrow to see how that pans-out = lighter wheels. Q for you lot with bigger brains than I- ignoring the obvious suckyness of the HvMaxx, would the new 6.5 motor with 3100kv & 500watts power have more torque and there for grunt than my old 4400kv + 375watt motor. Im guessing so but some second opinions are welcome.