Stock ESC rating

[mdg76]

Anyone know what the stock SuperCub ESC rating is?

[toff]

On the old Nimh stock, we worked it out about 13 amps max. No Idea about the newer BNF cubs.

[iflyforfun]

Im not sure where I read it or if the info was reliable but I've read 18amp.
Flydiver may have the answer for this one!!

[flydiver]

They use the same motor and battery as LP.
They use as many of the same components as possible to keep costs down (seen across a multitude of platforms)
They rarely improve anything unless the users are screaming bloody murder (ie. the breaking Radian props - pages and pages of complaints plus the liability of injury)

Therefore > it's likely 13A, but that's a guess.
They NEVER give away specs if it's not in the manual.

[iflyforfun]

Does anyone have a stock SC LP with a fresh charged and balanced stock 1300mah Lipo and a watt meter? If so, could you go to full power and post how many amps it draws in the first few seconds.
I would be very interested in how many amps a stock setup is pulling.

[rocketdork]

Tried this yesterday. A variety of batteries and a slightly banged up stock prop (I have to land in a gravel lot...not all landings are perfect)

Flight Max 2200 mAh battery (20C) about 11.5 amps
Stock 1300 mAh battery (15C) about 11 amps
OLD thunderpower 2200 mAh battery (20C) about 11 amps
Newish Turnigy 1300mAh battery (30C) about 11.5 amps

I believe I saw one run on one of the batteries pull 12 amps for a moment.

[flydiver]

11A with the 'new' 9x6 stock prop?
Not the 10x8 old stock prop? I think that one would pull 18-20A on lipo.

[rocketdork]

Yeah, the prop was a 9x6.

I 'spose if you spin it faster (higher voltage) you got to down prop a bit.

Any idea what the stock motor will handle as far as current?

[flydiver]

Pretty hard to tell. It's already gone past it's original conception by outliving NiMh and going to 3S lipo. After that there are so many variables about props folks use, throttle control-or lack there of, ambient temperature, etc that it makes it hard to tell.
If I were to hazard a guess it'll last awhile if used in the high single digit area (throttle control), and for every amp you go over 10A you maybe whack 5-10% off it's life. Most of the time it either gets tossed or crashed before that though it seems.

[Dillzio]

Thanks for the data rocketdork, good work!

I'm shocked that I often hear about people using the 'old stock' 10x8 prop and not burning out the stock ESC, but many people seem to get away with it without any problems. This is actually the recommended prop for if you put the floats on your cub, and for hobbyzone to be recommending it you'd hope that would be within the specifications of the stock electronics. I suppose that a stock cub, set up with the stock CG, would just shoot into the air at WOT, so perhaps WOT isn't used all that often with a 10x8 prop.

That stock ESC can probably take the stock running amps of 12A for extended periods, and can probably peak at around 16A for shorter bursts. It sure would be good if someone could test the stock motor with the stock 10x8 prop and let us know what the amp draw is.

In terms of what the motor can take, I suspect it's more than the ESC. It is only a brushed motor, any may need to be replaced every 6-12 months with heavy use (the brushes wear out), but I think it could probably handle 20 amps without too much trouble. Best way to tell what a motor can handle is to run it for a while then check the temp yourself. If it's too hot to hold in your hands that's a pretty good indication that you're putting too many amps through it.

[flydiver]

Oct 8, 2011 8:30:36 GMT 1 Dillzio said:

I think it could probably handle 20 amps without too much trouble. Best way to tell what a motor can handle is to run it for a while then check the temp yourself. If it's too hot to hold in your hands that's a pretty good indication that you're putting too many amps through it.

I think 20A continuous would make for a very short motor life. Temp is certainly useful but more so for brushless. Once you start pushing the brushed motor harder you not only get increased temp but you get significantly increased arcing on the brushes. This can take them out fast along with adding noise to the electronic circuitry.

3S lipo on 10x8 pulls ~18A. With a high-C 2200mA I think it might go 20A.
supercubclub.proboards.com/index.cgi?action=display&board=batt&thread=1831&page=1

I have no idea where HZ is coming from with the 10x8 on floats except that they have their head up there collective a$$e$. They certainly are capable of it.
Remember what I've said before, great customer service, but they never admit to a mistake.

HZ does not, and never will, publish the specs on their 'bricks/ESC'. They only way you find out is by burning one up. Unfortunately some folks burn theirs up with stock equipment right out of the box. Obviously this was garbage. They also NEVER have a wattmeter attached. At this stage they probably don't even know what a wattmeter is. ;D

OTOH, there ARE folks that use 3S lipo + 10x8 + floats and get away with it. Lucky? I don't know. I doubt they use full throttle the whole flight.
The stock 1300mA lipo is somewhat self limiting in terms of amp draw. Put a big and good 2200mA in there and it becomes a different equation.

[rocketdork]

Well, I'm a bit curious, so I think I'll order a cheap brushed ESC and see what the motor will handle.

I suppose I could also change out the FET on the stock board with something of a bit higher current and try that too.

I'm thinking of a 3 blade prop, not so much looking for increased speed, but some increased thrust. Perhaps an 8x6. The idea is to maintain some ground clearance. Larger wheels will help, I've ordered some. My landing skills and field (pea gravel compacted in some areas, not in others) have lead to some damage to the tips of the prop(s).

I'll report back my results.

[flydiver]

One of the problems with 'burning a motor up' is the cooling issues.
As the motor gets hot the internal resistance of the wiring goes up. This increases the heating even more. At a certain point the heating goes ballistic and you get run away heating and fries in apparent seconds. If you stay just shy of that point you may be able to abuse it pretty well.

You also have efficiency issues that people don't seem to get. A motor often runs at best efficiency about 1/2 propped and full throttle, kind of like driving your car at 45mph on the freeway. That might be a GWS 8x4 on the stock motor +3S. It would fly but take awhile to take off. Most effective prop seems to be the stock 9x6 or GWS 10x6. Not the most efficient (turning battery into flight) but gets you where you want to go better, like driving 65mph.

As you prop up from there you may gain some thrust but the efficiency goes down-like driving 80mph but your gas mileage sucks.
As you push it farther the efficiency falls off fast and the heat goes up very quickly leading to a failure.

The analogy falls apart at the higher end because an electric motor is not a gas engine. The electric motor will always try to run at full speed and will kill itself to do so. The gas engine will bog down and just not do the job.

[rocketdork]

I do get that. Adding power to the plane isn't to make it a fast flyer or the most efficient.

I have a lot of fun flying it. There are times though, that If I could grab a bit more throttle, I'd be happier. I recognize that it moves me off the efficiency curve somewhat and off the longevity curve. I'm OK with both. I feel like I recognize what I'm giving up, and what I'm gaining.

When the stock motor dies, I have a replacement for it, both in the brushed world AND brushless.

Putting a 3 blade prop on it gives me a bit more thrust for the diameter and better ground clearance, I'm trading efficiency though. I'm not looking to make it aerobatic. I've got other planes that fill that need. A 3 blade prop is sexy too!

The motor currently runs at about 130 watts input (peak). Adding another 20-30 watts intermittently is likely not devastating. I'm not trying to get something for nothing. I tend to fly it at about 1/2 throttle and that won't change much...just now and then, I'll grab a bit more throttle.