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[petermun]

My son and I were recently given a very old, (I`m guessing about 25 years plus), cargo type boat.   It was fitted with a giant Bob`s Board speed controller which is 2.5 inches diameter and 7 inches long.   This has been left in situ, but replaced with a modern ESC.
We have forum members who, like me, are knocking on a bit, and I wondered if anyone has any ancient literature on the subject.   Many thanks,  Pete

[Geoff]

No literature on the subject and a late reply. Many years ago I also used Bobs speed controllers with the wipers. They fitted directly on top of servo's. There were different sizes for different loads, low current and high current.


Fundamentally they worked okay but essentially introduces a variable resistance between the battery and the motor thus cutting down the voltage which in turn slowed the motor.


There were a couple of fundamental problems with this set up:


1) The wipers can burn or corrode a little and give erratic performance


2) They were not particularly efficient but they were cheap and worked!




Technology has moved on and we now use electronic speed controllers. Same issues with matching current but they work in a very different way as they switch the battery on and off so you get pulses of energy so if the battery is switched on and off 50% of the time you get 50% of the voltage and the motor runs at half speed, but with full torque and you are only using the battery for 50% of the time so longer duration. Thats a very simple explanation and speed controllers vary a lot in frequency. For example one that switches at 50 cycles a second won't be as smooth as one that cycles at 100 times a second.


Hope this may explain


Cheers


Geoff

[roycv]

Hi all I have one or two still in their packs if anyone is looking to do a retro fit,
Roy

[RST]

Hi, to answer the original question. Out of curiosity I just went to Google and typed "bobs board speed controller instructions", then selected images. 5th pic in are photos of what I presume are the old instructions on a thread via modelboats.co.uk website.  My phone sometimes throws things up in a different order, but pretty sure I have found it on my laptop before by essentially the same way.  Pretty sure you have found them by now though but worth saying.

[GG]

Bit puzzled by the original post in this thread.
The speed controller is described as a "giant Bob's Board" with cylindrical dimensions ( 2.5 inches diameter and 7 inches long).  This is nothing like the "Bob's Boards" I am familiar with.  They have all been a flat board, about 2 x 3 inches in size, which fitted on top of a servo.


To be honest this cylinder sounds like a rheostat that has escaped from a schools science lab?
Glynn Guest

[Stan]

Must agree with GG all bobs boards were rectangle in shape either way by today's standards it is obsolete something for model boat museum.


Stan.

[DaveM]

A piccy would be interesting. I have to agree with GG and SR. That thing must be nearly as old as you are, Peter! 
Dave M

[Colin Bishop]

Tamiya used to sell cylindrical rheostat speed controllers for model cars but this one looks smaller than described above.

https://www.youtube.com/watch?v=4WlzZzavvHw

Colin

[petermun]

Dave, just for you

[GG]

Ah....!  definitely NOT a "Bob's Board" then.  Can now sleep tonight knowing that my memory has not failed.


It's surprising how many people call any resistive speed controller a "Bob's Board". Bit like vacuum cleaners being called "Hoovers" I suppose.
Glynn Guest

[Stan]

Please do not take this the wrong way but this is one for the bin. May have been hitec many moons ago.


Stan.

[petermun]

Gents, I respect your views and comments.   I learnt about rheostats at Tech college over 70 years ago, I was just trying to keep  the subject in today`s context.   Pete

[Stan]

HI Pete no ill feeling's were intended. We have to remember this was all that was available at the time. Technology has moved very fast  giving some great products but also some headaches.


Stan.

[TheLongBuild]

Must agree with GG all bobs boards were rectangle in shape either way by today's standards it is obsolete something for model boat museum.


Stan.

Why, If it works and does the job why bin it, I have something similar in my Rau IX, probably works better than I do..

[Stan]

Hi longbuild  each to there own if you are happy with yours fine. The average model builder today would have no idea what this unit does or did. I am not putting a downer on this controller they were cheap and did the job.


Stan

[TheLongBuild]

That and too much hassle taking it out..

[malcolmfrary]

That and too much hassle taking it out..

That might change when it needs servicing.  Any resistance controller has the great virtue that it can be cleaned and adjusted.  The obverse is that it will need cleaning and adjusting.  If used with the right motor they give good, but steppy performance and are quiet.  ESCs seem less steppy because the steps are smaller, but do generate a characteristic whistle.
Presented with a lack of signal, a servo operated controller will just carry on, most ESCs, provided the radio doesn't do anything silly, will stop.

[RST]

Well I wasn't going to pick about what controller it was from the original description, it would have become clear from the photos on-line, but now a picture is apparent I'm tangentially somewhat fascinated as to what that set-up above it is with what looks like a small Lovejoy coupling on the right hand side?

[Stan]

Power in or out.


Stan

[Plastic - RIP]

That is junk - it's a home made controller with a commercial rheostat - it's being slightly misused - the wiper is parked at one end and the servo moves an additional contact touching the wiper's track.        I worked with valve-based RF systems and there were loads of those types of rheostats all over the place - you will be wasting tons of power just heating up your boat.

Just fit something modern - it will be much more efficient and reliable.

[Stan]

Hi plastic yes we all know these types of speed controllers are now obsolete but your comment its junk I feel was a little harsh. The idea of the forum is to help members not to shot them down flames.




Stan

[roycv]

Hi all back in the day (50years back) I used to use a low speed derived from parallel running and full was direct to the batteries all controlled from special relays from data processing equipment with rewound pairs of coils to run on 6 volts. 

The system was pulsed so no coils permanently using current and the relays were mechanical latching in a flip/flop configuration and were pulsed,  with 4 sets of contacts.  Control was from a Derek Olley RC set 4 ch non-proportional electronic tone system, worked a treat!  He later called himself Fleet.

Sounds complicated but it worked all the time, drive current was about 1 1/2 amps so no big deal.  Still have them and they plugged into sockets so a quick change would have been easy.
A' servo actuator' was an ordinary actuator but with an electric motor so you could have a 'progressive' rudder control.  I made my own from an Ever Ready TG 18 motor with a gearbox attached I made it self centreing but it would hold a position.

I never tried the 'Galloping Ghost' system!

I built a 'Pompey' speed controller (published in Model Boats magazine) which had a 4 off OC 29 H configuration ouput so full speed had two transistors in circuit each losing 0.7 volts across the emmitter to base junction.  I later 'pinched' a circuit for my own use which detected the high speed full current across a resistor connected between the emitter and base which when it reached 0.7 volts  turned it on and this called a relay which switched the motor direct to the battery, this gave the motor another 1.4 volts, I had high current contact relays for this.
Anyone looking for old transistor types feel free to P.M. me

All good fun.
Regards
Roy

[TheLongBuild]

To one person it is junk, to another it is nostalgia, if it works and the operator is happy with it and the performance then all is good in the world, why spend / waste money when there is no need to.
I can see it coming, what you still use brushed motors, WoW, you should be using brushless with lipo,s....




To borrow a saying from another member..


Each to their own..

[chas]

I can't help wondering how many of the people replying on this thread have read the original post. Some ' answers ' border on the rude, and are well wide of the question. To clarify, he states that the old controller has already been replaced with an esc, the old resistance controller was just left in the model.

[DaveM]

Have I missed a couple of pages here? Peter Munday said in his OP that the items had been disconnected so why is there so much flak flying around about using one? Unless you are intent on making a replica of a vintage RC model boat then there's no reason to entertain the use of such an outdated and inefficient piece of equipment. I agree that in its day it was probably the best solution around, but so were the valve receiver and the ground-based single-channel super-regen transmitter.
I'm 100% with Chas Oates here. Like so many threads on this forum what began as a simple request for information (read it again..) has turned into something far less wholesome. Get a grip, chaps - it's just a hobby.
Dave M