as I understand it, the loads that a surface vehicle puts on the esc are very different to what an aircraft does. if it had car software so it responded like a car esc, it would let out the smoke a lot more easily.

OMG so basically:

a^2 + b^2 = c^2
16^2 + 80^2 = c^2
256 + 6400 = c^2
c^2 = 6656
c = 81.58"

16^2 + 48^2 = c^2
c^2 = 256 + 2304
c^2 = 2560
c = 50.596"

80^2 + 48^2 = c^2
c^2 = 6400 + 2304
c^2 = 8704
c = 93.3"

Max. Length
d = sqrt(a^2 + b^2 + c^2)
d = sqrt(80^2 + 48^2 + 16^2)
d = sqrt(6400 + 256 + 2304)
d = sqrt(8960)
d = 94.657"

Answer to the Ultimate Question of Life, the Universe, and Everything is 42. why didnt the article just say that at the beginning? OMFG!!!

well, I know that there is no such thing like a proper break in these things. why? dammn, the're made for planes... comments like that= crap.

thats why I will get myself a proper car esc. there are some new ones coming out right now here in germany, and when they have proven to be good, I will get one.

BUT:
the reliability and the cogging-free throttle is - at least at the one I have - just great, nothing less. So I wonder, why can't other esc's of big brands be at least the same reliable? I've payed about 40,- euro and only water was able to kill them, indestructable stuff.

That is something I can't understand, and that was the point of my post.

florian

its not the brakes that is the problem. Go and do some jumps. You will notice sometimes if your throttle isn't perfect, the nose might dip a bit in mid air, and to correct it and land on the landing ramp smoothly, you blip the throttle just a tad and the gyro effect brings the nose up a little to stop it from nose diving.

Using a car esc, this is possible, because they allow the motor to spool up quickly enough to give a fast rpm change like that. This fast rpm change is when peak current is drawn - on the road in a truck castle measured peaks in excess of 800A. These peaks arent visible on eagle tree etc because they are only momentary, but as far as the electronics are concerned, they still happened. The FETs in the car escs can handle thes momentary rushes of current.

In an aeroplane or a heli, you dont want the prop to spool up to full speed in a fraction of a second, so they limit how quickly in can spool. in the same jump scenario above, you blip the throttle to bring the nose up and you've hit the ground on your roof before the rpm increases significantly. This way the Air escs can use much lower rated FETs because they dont experience the extreme current peaks that car escs do. This is also why they dont cog, because they are designed to spool up slowly, because thats what you want in aircraft. this also has the effect of much lower peak current draw.

I have some graphs showing a voltage rise w/ my MGM 9032 and 10A A123 a while back. Nothing huge, but noticeable.

I always loved my MGM. Tons of power and it barely ever got warm. 110F at most. HV did help a lot. Very solid controller, water proof/resistant coating also.

It should be understood too that at the time, there was very little choices for controllers. You had the cheap MM that worked pretty well for 4S (and was a relief when that came even,) a pricey Novak that thermaled easy and wasn't fast, but if you wanted more than that you had to get a $$$ controller. Things have changed really quickly. Go back to threads from even 2007 and see how it was. 2005 may well have been the BL equivalent of the 1920's Flatheads for gas powered engines.

thanks for that reply, very interesting.

to adjust the car during "flight" is truly tricky, as especially the breaks don't react immeadetly. by now I got used to it, almost. but throttle-response I would actually compare with the GM genius controller I used to have. My car is a truggy-style buggy, on 5s / 1700kv losi motor, about 4,4 kg total. I drive it on tracks as well, so handling with the cheapo-esc is good. except the breaks, which really s..k.

I used to have an etti controller (2 yrs ago), which was no good for car use at all, even for me... I also tried a scorpion commander 120a esc, which supposed to have a car-software. unfortunately mine didn't have that, and I have to say that I wasn't happy with the throttle-curve at all and there was cogging; acceleration was kinda lame, can't describe it. it also went up in smoke after a few rides, (got it replaced and sold it). the cheapo-one is much better...

I have once read that most of the chinese-plane esc are based on jeti-controllers. and somewhere else I have read that in such large esc's older/different fet's are used. these are larger, but like that can handle heat better and are more "rugged".

Anyways, as I am planning to get a car-esc (I think the new GM genius 120R), I just pray that it's reliable like my cheapo-esc. I just got used to worry-free driving.
florian

I have a 8s mgm esc. I was planning om running it on 6s, so no problem there. But I also want to run it on 8s occasionally. The esc has 4 50v caps. Now I'm wondering if it's safe to run the esc to it's full specs after reading the article?

You should be able to just don't brake!

I've always pushed the voltage limits of my ESC's but never had issues probably because I've always used mechanical brakes on my MT's and 1/8th scales. I've used up to 15% motor brakes, to get some front braking power, but thats about it.

I am running 6s on the Quark (the Quark has issues with 6s), and I use only 45% brakes MAX, the EPA is set to 45%, and I usually use only 1/2 of the full 45%.

The way I brake, is usually a small amount when at speed, then I gradually depress the brakes more when it slows down, to keep the same braking action. I have never really used hard brakes ever, it's just too hard on things, drivetrain, motor (heat), and esc obviously....

There needs to be an "at the wheel" disc brake kit for these large vehicles. Like what FG Models uses on their 1/5 scale beauties... a brake servo that depresses an oil cylinder with 4 oil brake lines going to smaller discs at each wheel. This would take all the stress away from the drivetrain, and would also give a much better braking feel.

I have a question for the pro's :smile:

In general the wireing should be as short as possible, the solder job as good as possible & the connectors should be of good quality... that much I know.

But... if I should choose between long wires from battery to ESC or from ESC to motor - which would be best? Id guess option 2 is better since the voltage drop is then on the "non battry side" of the ESC?