ESC converting my electric glider

Firstly forgive my ignorance.
I have an Electra glider I built many years ago it uses a brushed motor think from memory it's a 550 can't remember the make.
When I first started there was no ESC's, so I used a heavy duty switch and a servo to actuate the switch on and off with an in line 20amp fuse. Hence you get either got full power on or motor off and glide.
Worked fine and presumably still will when I have finished my minor repairs.
However, I am thinking ahead to the future and planning to change to an ESC, thus eliminating the servo and switch providing throttle control.
I have found a brushed 30amp ESC by Turnigy (think that's the Spelling).

First question: would the 30amp rating be okay ? Firstly with my 7.2v Nimh 2200 mAh battery and separate RX battery.
Secondly could I continue to use it if I convert to a 3S Lipo battery in the future ?

Second question: there are plenty of higher rated ESC's about 40 to 60 amp but some are stated as being for model cars or boats, can these be used on model planes ?
I would be swapping over from my Nimh 7.2 battery pack (with separate rx battery), to a Lipo cell 2200 mAh 3s 11.1 volt. This would eliminate the rx battery assuming the ESC has a BEC built in.
I guess most of this has been covered before many times, but if I don't ask I won't find out.
Regards Ian

Ian
Make sure it is an ESC for brushed motors (two wires to the motor). The vast majority of aeroplane ESCs are now for brushless motors and have 3 wires. They are not interchangeable.
A 30A should be fine but if you are going to do much experimenting get a Watt meter so you can measure the Amps that are flowing out of the battery (a Watt meter works just as well for brushed or brushless).
ESCs are electronic components so really do not like being over loaded even for a fraction of a second so a Watt meter is likely to pay for itself very quickly!
Car ESCs are usually built 'heavy' (weight is not so critical in a land vehicle) and usually have a reverse function as well. The bigger ones can have a cooling fan built in as there is no natural airflow.

Thanks that's really helpful.
That means I could use a car ESC in a plane as long as weight isn't an issue.
I have a basic multi meter so I can measure the voltage and current, this will give me the the power i.e.
VxI = Watts ?
I can also get the brushed motor in my Electra glider working with the 30 amp ESC. I will probably run this until the brushes need replacing then change over to a brushless (3 phase) motor in the future, with a higher rated ESC. I can use the weight difference in motors to compensate for a weight increase in ESC !
I can then refurbish the old brushed (2 phase) motor with new brushes (think I have spares, that originally came with the motor) and use it on another project.
Great that clears up a lot and gives me some future mods I can start progressing through.
Thanks Again for the help and feedback.
Ian

An ordinary multi meter is unlikely to be able to read the amps most planes use. Even a cheap Watt meter (like I have!) will read up to 100A.
I would expect a 550 brushed could easily draw 20 amps, particularly if it is stationary and just 'switched on' directly to a battery. You could get away with doing that on a NiMH or NiCd but a LiPo has a much lower internal resistance so it can deliver as many amps as the motor allows and when its stationary it is to all intents and purposes a direct short circuit!

I'm a bit unhappy about attempting to use any ESC other than one intended for aircraft use. Somewhere I've read that the motors have speed sensors in them which have to be wired back to the ESC in order for it to work correctly. I could be wrong.

Is this a Carl Goldberg Electra? In which case the all up weight can be expected to be about 3lbs so 150 to 200 watts should do nicely.

Starting at the beginning, you said you used a 20 amp fuse, so assuming you never 'blew' one, a 30 amp esc will be fine - but as stated, it MUST be one for a brushed motor, not a brushless, it is totally different technology.
You put - Firstly with my 7.2v Nimh 2200 mAh battery and separate RX battery.
Secondly could I continue to use it if I convert to a 3S Lipo battery in the future ?
That depends on the spec's for the speedo. A 3S lipo delivers over 11.5 volts, at a LOT of amps, depending on what it's 'burst' power reading is, so you could potentially deliver 100 amps or more to the speedo! It normally states what the normal and burst power levels are, on the lipo casing. One I have to hand is a 3.3 AH 4 cell, with a 90C ( 90 times capacity) discharge - that means it can deliver3.3 X 90 = 297 amps for a short burst! That would make your eyes water a bit! (the battery would get rather hot, too!) The 3.3 bit means that a one hour charge at 3.3 amps would charge it to nominal full. You can charge faster, assuming your charger is capable, but fast charging reduces the battery useful life.

As I put in a previous thread to you, a WATTMETER is vital. Your pocket multimeter is virtually useless for this purpose, you would fry it in seconds at the kind of power levels we are talking about.
The same for your existing motor. it was designed for 7'5 volts, and shoving nearly twice that into it WOULD make it spin faster, at a price! The price being a very short life.

As Klippy put, a brushless motor is very different in construction, bulk, power, and weight. Also there are two different kinds - an out-runner, where the outer casing spins to drive the prop - the back-plate is fixed to the firewall,, and the in-runner, which looks more like your brushed motor, where the armature is inside a fixed casing. Out-runners deliver more torque, and in-runners more rpm's.
All brushless motors have a kv number - this is the number of rpm's per volt.

Also as Klippy put, there is a 'feed-back' monitor in the speed controller (which can be user-altered) that controls the timing of the power pulses, so the right winding of the armature gets the right pulse at the right time, to make it spin in the right direction! By changing over any two of the three wires between speedo and motor, you can make it spin the other way.

Yes it's the Goldberg Electra never actually got around to weighing it.
It came originally with a Graupner 550 brushed motor which fell apart after a bad landing, so replaced it with another motor same rating.
As I used a 20 amp fuse I assume that's what the original manual specified never blew a fuse.
If I was upgrading to an ESC control I assumed 30 amp would be sufficient as I wouldn't be running the motor flat out all the time. Once I got decent altitude I use to glide as much as possible. Always left enough charge in my battery to help get a controlled landing.
I am leaving it as is initially so I can get a few flights in once it's all repaired. Then I plan to change over to an ESC control, Lipo battery and a couple of 9g servos to reduce the weight.
Eventually I suppose the last upgrade is changing over to a brushless motor and new ESC with a 2.4ghz set. But that's a while off yet.
Regards Ian

I assumed 30 amp - - To quote a character in a film - Assumption is the mother of all f***ups!

ESC is rated 30 amp continuous 40 amp burst.
As original motor under full load never blew 20 amp fuse I assumed the ESC would be adequate.
But " To Assume is to make an ASS of U and ME ".
Cheers

I will bench test under full load, with my new multi meter that arrived today.
Got it to trace the fault on my FP transmitter which is already fixed, thought I had wasted money obviously not.
Thanks for the feedback.
Ian

I wouldn't do that if I were you, your meter will only handle 10amps and the supplied leads less than that. The only way that you can measure the potential current is with a current shunt or the correct equipment designed for the job.
The reason I mentioned being wary of Car ESC is because in aircraft we supply a variable frequency 3 phase power supply from the ESC. Low frequency = low rpm, high frequency = high rpm. We don't monitor the rotational speed of the motor we just let it do it's thing. In cars, and for all I know other branches of our hobby, the motor has extra wires that feed a speed signal back to the ESC to ensure the motor is rotating at the correct speed, this could give rather surprising results in an aircraft

Realised this weekend that my multi meter isn't up to the task, shame I sold my old one that would have easily managed it.
My new motor, prop and dedicated (rc plane) esc arrived at weekend for my other project.
As for the ESC I was planning to buy for my glider upgrade that was also an aircraft dedicated version.
I was just interested if the car ESC's where usable on aircraft as they appear to be higher rated for a fraction of the cost for a dedicated aircraft version.
You answered my question.
Much appreciated Ian

Ian
I suspect most of the difference is due to demand - brushed motors on planes are now quite rare.
Looking at the Hobby King web site it would appear the 30A brushed ESC for vehicles only have a 1A BEC which is a bit low if you have more than 1 servo. You also have to set a jumper to get the correct low voltage cut off (LVC) if you use a LiPo battery (plane ESC's have an auto detect system) but apart from that they look usable.

I note a brushless 30A plane ESC with a 3A BEC is virtually the same price as a brushed 30A ESC with a 1A BEC. Go up to 60A and plane ESC are cheaper. Supply and demand?

Got another couple of questions
Being new to this I didn't appreciate that the ESC would need to be calibrated, although in hind site it makes sense so should have expected it. The only examples I have seen use new TX and RX gear 2.4 ghz.
Can I still calibrate using my old 35mhz gear that doesn't have programmable transmitters ?
Next question the ESC I got with my new brushless has a 2 amp BEC, assume that's ample with two 9g servos ?
There is a lead with black and red 22 awg wires culminating in a JST connector I assume this is the power supply from the BEC ? If so will need to convert it to a Futaba connection for my receiver.
Not checked the ESC from Turnigy that I was planning to use for the brushed motor in my glider, but don't think it's got BEC built in. Not a problem as I was planning to use my 3500 mAh Nimh batteries to power the motor with a separate RX battery. Used 2200 mAh nicads last time it flew, with a 4.8v rx battery, so there wont be any additional weight gain.