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[murphy1570]

Hello folks
 
I understand a standard servo motor can be used to drive small model boats ie plastic kits converted to radio control, can anyone advise me on how this is done and do I need to use an esc with it or just hook it up to the throttlle control on my reciever, would just using the servo motor give some speed control and also reverse given the limited room within the hull of these small kits (12" or so). Any advice on how to extract the motor from the servo and if it needs any modifications to carry out the functions mentioned above, given my very limited knowledge of most things involving electronics.
Thanks in advance all the best, John.

[Umi_Ryuzuki]

Here is a good link showing servo modifcation for main power.

http://www.mhsd.org/model/howto/servo.htm

 

[tica]

Hi

I'm planning to use 2 converted servos for my 1:40 Lifeboat. They have been taken apart, this is very simple.

I have found 2 issues that may change my mind.

1: Full speed is achieved at ½ of The movement of the throttle stick, this can be solved if you uses a programmable transmitter.
2: The 0 adjustment (where the motor isn't turning) is not very easy and it tends to change during use.

I'm planning to ditch the servo electronics and use a small ESC Robbe rokraft 50uP.

BR
Carsten

[inertia]

Too much effort fo very limited reward. This was designed for the job, and is just a little larger than a thumbnail without its case. http://www.action-electronics.co.uk/pdfs/P68A.pdf  You can read the other features for yourself.
DM (No commission - honest!)

[Mad_Mike]

Hello folks
 
I understand a standard servo motor can be used to drive small model boats ie plastic kits converted to radio control, can anyone advise me on how this is done and do I need to use an esc with it or just hook it up to the throttlle control on my reciever, would just using the servo motor give some speed control and also reverse given the limited room within the hull of these small kits (12" or so). Any advice on how to extract the motor from the servo and if it needs any modifications to carry out the functions mentioned above, given my very limited knowledge of most things involving electronics.
Thanks in advance all the best, John.

I have used the servo amp for a very small 3inch springer tug. They work ok but like as been mentioned but they do have there issues one being that when you put the stick centre to stop they kinda wobble a bit a buzz. Another good source of esc's for small motors and boats like yours are these:
http://www.ebay.co.uk/itm/RC-20A-ESC-Brushed-Motor-Speed-Controller-for-RC-Car-Boat-Without-Brake-/281036936134?pt=Motoren_Getriebe&hash=item416f1b53c6
I have 2 of these and they work very well.

[malcolmfrary]

Without modifying the servo electronics, the small travel for full control is easily overcome by using that sticks trim slider as an engine room telegraph.  The very small deadband is not a real problem when working a boat since if the boat is in the water, you don't often need a dead stop.  Used as a winch, replacing the servo electronics with one of ACTions Pico ESCs works well, because that is one place where a good positive stop really is needed.
The big problem is getting a reliable mechanical coupling with the very short motor spindle.  This is another good reason for a Pico and one of ACTion's mini motors.
For a bit more power, the modded servos are OK with 5 cells (talking NiMH here), the ACTion Pico ESCs, if I remember right, are limited to 4 to avoid frying the PIC chip.

[Mad_Mike]

ive missed something here. The motors in servos are pretty small and the spindle is tiny like 3mm long with usually a press fitted brass gear on. If you want a motor thats small look in pound shop or something for one of those hand held electric fans thats take the 2 aa batteries. Take a screw driver to it and rob the motor from that. Itl turn a 20-25mm prop quite well without destroying itself. You can use electrical sheathing from a peice of wire as a coupling to a 2mm prop shaft. 

[Martin (Admin)]

Converted servos are very popular in small boats, eg, 'Airfix' conversions - popular as you have a speed controller and motor for as little as £5 ,ie the cost of the servo!