MY turn to Ask the QUESTIONS - Page 3 - RC-Monster Forums

hyperasus · 03.26.2007, 03:38 AM

No offense to the rc calculator, but if you run the ratios on it at that KV it'll look slow. I find the calculator to be great for comparison purposes though. according to the rc calculator a 2600kv motor with 86t-spure/30t-pinion should only do 50mph, 55 tops on 3s lipo. Just isn't the case though. I've done 60 and it still had power to spare. Any faster and the nose of the truck goes up.

I haven't had a jato, but I still find it hard to believe a mm4600 can push a Jato without getting hot. You must really drive your trucks softly. Or have super week batteries.

BrianG · 03.26.2007, 03:24 PM

Quote:

Originally Posted by hyperasus

No offense to the rc calculator, but if you run the ratios on it at that KV it'll look slow. I find the calculator to be great for comparison purposes though. according to the rc calculator a 2600kv motor with 86t-spure/30t-pinion should only do 50mph, 55 tops on 3s lipo. Just isn't the case though. I've done 60 and it still had power to spare. Any faster and the nose of the truck goes up.

I haven't had a jato, but I still find it hard to believe a mm4600 can push a Jato without getting hot. You must really drive your trucks softly. Or have super week batteries.

No offense taken. If the actual speeds are greater than calculated, there MUST be something to account for it; kv value is higher than spec'd, tire balooning, voltage maintaining a high level, etc. The calculator is not magic; it's just kv * voltage / total reduction ratio * tire circumference / 1056. (the 1056 is simply a simplified conversion from in/sec to mph). It's just math. Other people have used it and it comes out pretty darn close.

The 4600 pushes the Jato around with ease and does not get hot. And it's geared tall to get 47mph out of a single speed tranny and only 2s. I don't think the temp has gotten above 140* (measured). As far as driving style; well, I don't mash the throttle from a standstill all the time - that just wears out my tires. :) Oh, and I'm using 2s2p emoli packs for batteries. Cutoff is set to 3.1v/cell and the LVC doesn't kick in until the pack dumps, so the battery voltage isn't sagging badly.

@crazy: OK, "most" of the Nitros are built tougher. ;)

Serum · 03.26.2007, 04:03 PM

Topic moved to general questions.

glassdoctor · 03.26.2007, 04:25 PM

Like Brian said the calc program is simple math. You can do the same thing with pencil and paper.

With a known kv of the motor and the voltage of the battery, either measured or estimated realisticly... you can get very close to actual speeds achieved.

The only thing you can't easily account for is the losses in efficiency of the esc and motor. If you assume a 20% total loss that's probably close in most cases.

I'm guessing most of the time that the calculator is off it is due to guessing the voltage drop wrong, or the kv of the motor isn't exactly what it's rated. For example Castles motors are not exaclty as they are labled... 4600 is not 4600kv but it's close to that. And the voltage while at top speed can be tricky to guess...

hyperasus · 03.29.2007, 10:19 PM

MF2 good basher? not as hard to break as MT? Low maintenance and running cost?

I don't know about all that. Sure not the experience I've had with my XXX-t trucks. In fact I find it to be the complete opposite. XXX-T are good for racing and racing only. They handle good if you know how to set them up right(hard to do). They are also very fragile and really not all that cheap to maintain compared to pede/rusty.

squeeforever · 03.30.2007, 12:48 AM

I kinda agree. The XXX's aren't very durable. I think they are rather easy to setup, though that was my first RC so I dunno...I got use to it pretty fast.

Gustav · 10:27 AM

I was talking about 1/10 stadium trucks in general,rustler included,in comparison to MTs,it's just i happen to run that one so i gave it as an example.i find them extremely durable,owing to the fact they weigh next to nothing,they don't have the inertia to hurt themselves very often.drop a spider from a second floor window,then an elephant and see who comes off best.Durability is a prime concern in racing too.As for XXXTs only being good for racing,well i have a blast with mine anyway.I still think a 1/10 stadium truck is cheaper to run than and break less than a MT,and less time consuming,some more than others naturally,like you say the traxxas trucks since they have that bit of flex.having the planetary diff and not a ball diff should make for less maintenance too,can't go wrong with the rustler/pede for lot's of reasons,availability of parts,cost of running,maintenance,durability,fun etc.

JAM · 04.01.2007, 07:06 PM

Well here's the deal guys.....Mr1st (user name here) is offering me a 06' Rustler with stock TX and a MM 5700 with ESC.....I will not get into the details of the deal. But I think it's a really good deal. It should be a good little test bed and a great way to get the kid into a BL set up. The only thing that worries me is that he isn't responding to my request for his address.

JAM · 04.03.2007, 05:14 PM

Well after finding out where MR1st is located (Somewhere in the Middle east, he wouldn't be specific) And this has nothing to do with him personnaly it's just that At this time and point I will not ship or receive anything from that region of the world........and the same goes for most carriers. So the deal is off and my search continues.