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Giles

Radio Controlled Traction Engine, Mechanical Horse, Steam Crane, Road Vehicle, Gantry Crane, Mobile Crane and Bedford TK Artic

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I decided I wanted a van or lorry to provide some movement on my next 7mm layout, (not much room for it on 'The Loop'!) and of course there doesn't seem to be anything suitable or easily adaptable out there - but do tell me if there is....!

Finding a lorry suitable for the late '50s isn't entirely easy, but Corgi do this nice Morris, and I picked up a couple on Ebay

IMG_6398-Copy.jpg

Since it's possible to put radio control gear into 00 gauge diesels, I reckon it's got to be possible to make something like this go, so we'll see how we get on. It may fall flat on its face and get nowhere, but it's worth a try, and people may find it interesting!

First job is to strip it down. Screws in the bottom (the front one underneath a little cover). Kit of parts.

IMG_6399-Copy.jpg

It should be reasonably straight forward to make a new back axle, motorised with a Portescap RG4 or modern equivalent, so I'm not too worried about that. The tricky bit will be the front steering axle with the ackermann steering.
The first job is to make wheel hubs with bearings. The new hubs are machined out of steel, 8.5mm diameter, to take bearings 3.95mm OD, 1.5mm ID x 1.2mm across - a fairly quick job on my little Unimat 3. Bearings from Ebay.

IMG_6407-Copy.jpg

Its all very, very small....

IMG_6408-Copy.jpg

Completed hub.

A cruel photo of the two completed stub axle assemblies made from blocks of nickle silver, with king-pins and steering arms of 1mm dia MIG wire (steel). The actual stub axle is 1/16" dia silver steel, run down to a slight taper with a needle file in a lathe, so the 1.5mm bore of the bearing fits snugly on it. It is then retained with a ring of copper tube (again, 1/16" bore). These now spin quite freely, and are ready for the wheels, which need slight modification.

IMG_6416-Copy.jpg

More as I do it....

Edited by Giles
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This looks quite an ambitious project! Good luck! :)

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Modified the front wheels today - - removed the rear boss, opened out theback slightly and glued them on to the new hubs and watch them spin!

 

IMG_6417-Copy.jpg

 

IMG_6419-Copy.jpg

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Interesting project. Are you planning to give the vehicle any suspension travel? While the Faller system for HO is impressive, when closely observed the 'skittering' effect as largely rigid vehicles bounce along on any three wheels out of four doesn't match the smoothness of what is moving on the rails.

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Interesting project. Are you planning to give the vehicle any suspension travel? While the Faller system for HO is impressive, when closely observed the 'skittering' effect as largely rigid vehicles bounce along on any three wheels out of four doesn't match the smoothness of what is moving on the rails.

 

I was planning to pivot the front axle allowing it to rock to give it a little 'compensation', as most of the weight will be over the back end (batteries, receiver, motor etc.) rather than actual springing. This should give four-point contact on normal roads.

Of course what I'd really like is a miniature differential, which would make all the difference cornering, but I'm not up to making one (I want to keep this relatively simple!) and I don't think anyone produces one this small - but if they do - let me know...... and I'll think again about the drive train.

I absolutely agree that the motion has to be smooth and realistic - otherwise it wasn't worth bothering - but with a well controlled final drive (such as a portescap...), decent proportional steering, and all four wheels on the ground, I don't see why it shouldn't be?

(how it copes on any hills is anyones guess....)

 

I'll have a further think about whether I can sensibly incorporate springing into this - I rather think it might be a bridge too far, but we'll see.

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Certainly look like an interesting project.

 

I assume you are planning for the final thing to be fully fuctioning, as in forward / reverese, varaible speed etc.

 

Where are you going to fit all thebatteries / radio control gear etc?

 

Within a dummy loan perhaps?

 

Lookign forward to more updates.

 

Andrew

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You mentioned differentials, the best way really for smaller road models is one wheel drive, it works fine, and no slipping on tight corners.

 

Also have a look at the indoor flying servos, very minute items, some fit on a 10 pence piece, and are not too expensive.

 

The speed control can simply be a board from a micro servo, with an added driver transistor if the current drain is above about 25-100ma. The feedback potentiometer is removed and you have proportional control, not very sophisticated, but able to directly control a coreless motor perfectly as that is what it is designed for!.

 

You might even be able to use the coreless servo motor and gearbox, with the tab removed from the gearbox that drives the potentiometer........ a lot of robot makers follow this path, and there is lots on the net on how to modify servos to use as controllers or gearboxes.

 

..and for the size flat lithium batteries like phone batteries pack the most Milli ampere/ Hours figures for the volume.......

 

Stephen.

 

Stephen

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You mentioned differentials, the best way really for smaller road models is one wheel drive, it works fine, and no slipping on tight corners.

 

Also have a look at the indoor flying servos, very minute items, some fit on a 10 pence piece, and are not too expensive.

 

The speed control can simply be a board from a micro servo, with an added driver transistor if the current drain is above about 25-100ma. The feedback potentiometer is removed and you have proportional control, not very sophisticated, but able to directly control a coreless motor perfectly as that is what it is designed for!.

 

You might even be able to use the coreless servo motor and gearbox, with the tab removed from the gearbox that drives the potentiometer........ a lot of robot makers follow this path, and there is lots on the net on how to modify servos to use as controllers or gearboxes.

 

..and for the size flat lithium batteries like phone batteries pack the most Milli ampere/ Hours figures for the volume.......

 

Stephen.

 

Stephen

 

Thanks Stephen,

 

I had thought about driving just one wheel but I wondered whether it might sit there and spin - perhaps I better just try it...!

 

This was the servo I was thinking of using - nice and small at 3.7 grams

 

servo.jpg

 

but so far I've not managed to find a receiver smaller than this - which is about 35mm long x 25mm or thereabouts...

 

receiver.jpg

 

I'm afraid you lost me a bit with the speed controller - will the board from a servo (minus the feedback potentiometer) give reverse as well?

 

All very useful stuff!

 

Thanks!

 

Giles

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Certainly look like an interesting project.

 

I assume you are planning for the final thing to be fully fuctioning, as in forward / reverese, varaible speed etc.

 

Where are you going to fit all thebatteries / radio control gear etc?

 

Within a dummy loan perhaps?

 

Lookign forward to more updates.

 

Andrew

 

Hi Andrew,

 

It'll probably end up as a box van, which will give me plenty of room to play with! Yes, as fully functioning as I can get it.... It should be quite fun if nothing else.

I must say, as far as donor vehicles go, this Corgi Morris is quite a good one - the wheels are quite easily modified and look good, and it all comes apart very easily.

 

G.

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Thanks Stephen,

 

I had thought about driving just one wheel but I wondered whether it might sit there and spin - perhaps I better just try it...!

 

This was the servo I was thinking of using - nice and small at 3.7 grams

 

http://i589.photobucket.com/albums/ss338/giles61/RC%20Truck/servo.jpg

 

but so far I've not managed to find a receiver smaller than this - which is about 35mm long x 25mm or thereabouts...

 

http://i589.photobucket.com/albums/ss338/giles61/RC%20Truck/receiver.jpg

 

I'm afraid you lost me a bit with the speed controller - will the board from a servo (minus the feedback potentiometer) give reverse as well?

 

All very useful stuff!

 

Thanks!

 

Giles

Yes the board alone with the pot removed will control a motor, speed and direction, there are articles on the net on how to do it....the small items come from Peanut flyers on RC....again on the net, I will try to source them.

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This is one of the US sites, and has typical receivers......some smaller than a five pence piece.... the site has actuators and servos, and there are UK distributors of most products.

http://www.microflight.com/Online-Catalog/Receivers

 

The size may come as a shock, one is as small as a Futaba connector. German modellers use them in HO scale cars.....nuff said!!!

 

Stephen.

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I have used the micro caseless .8grm servo on this page, excellent for a vehicle, without changing to a coil actuator, which will not suit steering in a vehicle.

http://www.micronradiocontrol.co.uk/falcon_radio.html

 

They also do receivers with the servos on board, very handy. You will need to read up on the frequencies most use the new ultra high frequencies for stability. Micron will give information on legality in the UK. ...and ground based use. They are very unlikely to interfere with anything, short range and low power.

 

These small units are way more sophisticated than FM R/C.........

 

Stephen.

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DO NOT FORGET.....the speed controllers for planes are forward only!!!! Try robotic sites to find reversible controllers, or modifying servos to do the same task.

 

 

Basically you may get the lot, including the battery in a matchbox, with space to spare!!!!! The Falcon units are UK made by the way.........

 

Stephen.

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With items from the Micron site there is no reason to go beyond using only the space for the engine under the bonnet, the back can be empty, even a Lipo battery would fit as the fuel tank,

  • In O scale I would expect the vehicle to give no give away that it is radio controlled at all, virtually completely hidden......

Now there's a challenge, made possible with the tiny servo from Falcon, the 1.6grm one. The tiniest may micro glitch too much for steering, but the 1.6 is pretty steady.

 

The Peanut scale planes I build are 12 inch wingspan scale types, fully proportional, able to take off and land under power. With the light load of a geared motor in a vehicle you would get say a half hour of use per charge or a bit more, and charging takes only a minute with electronic controlled safe chargers. The planes motors draw much more power and flights are shorter at about 5 minutes or less.

post-6750-127870601053.jpgtypical small lipo batery, use in place of fuel tank.

Stephen.

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The speed control can simply be a board from a micro servo, with an added driver transistor if the current drain is above about 25-100ma. The feedback potentiometer is removed and you have proportional control, not very sophisticated, but able to directly control a coreless motor perfectly as that is what it is designed for!.

 

 

Stephen, all this information is quite brilliant, and rather mind-boggling! I had no idea that decent Radio Control had got this small...

 

 

IMG_6420.jpg

 

At present, I'm planning on driving it with an RG4, like this, which may take maybe 500ma ? Should I use a card from a bigger servo, or, forgive my ignorance... addind a driver transistor ....? I could do with an idiots guide on this one - I have normal common sense, but electronics (as opposed to electrics) is not my bag - but I'm willing to give most things a go!

 

That little 1.6gm servo looks very good, but it's very little smaller than the 3.7gm one?

 

KEEP IT COMMING!

 

Giles.

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On the Portescap motor it would not draw 500ma, as you will not be using full 12 volts, the radios use 6 volts of so, (2x Lipo batts), and most coreless motors draw only about 25/50 ma to run, and the load is light on the Portescap.

An alternative is the tiny motors and gearboxes used in camera lenses for autofocus, a supplier here:

 

https://secure.precisionmicrodrives.com/

 

or rivals on Ebay. They are small enough to go across the lorry, and have a belt drive, (Nigel Lawton) to the axle .....they are not coreless, but are low voltage and drain, and quite inexpensive, have a look at the smaller versions. If you get small plastic 1:1 bevel gears it could be mounted in line under the floor.Most are very high geared, 150:1 perfect for vehicles low speed range.

..........to finance the radio and motor, you then auction the Portescap on Ebay!!!!:rolleyes:

 

I will try to find relevant articles on servo conversion to speed controllers.

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post-6750-127876153592.jpg

 

see: http://cgi.ebay.co.u...=item563975ae3e

 

These are ones I have used before, 100:1 (other ratios available), small enough to go across the bed, with a belt drive from Nigel Lawton to the one rear wheel. They are low drain, not coreless, and exceeding powerful.

The higher ratios are more suited to vehicles than the Portescap. The gears are made to very similar standards.

 

Stephen.

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Also, and this will make you wince.... 4 wheel drive RC trucks, vans etc, in HO 1:87, have a look at the UTube links for cars and trucks, and, yes, these are full RC in HO, with lights etc., plenty of ideas and inspiration.

 

 

Stephen.

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https://www.rmweb.co.uk/community/uploads/monthly_07_2010/post-6750-127876153592.jpg

 

see: http://cgi.ebay.co.u...=item563975ae3e

 

These are ones I have used before, 100:1 (other ratios available), small enough to go across the bed, with a belt drive from Nigel Lawton to the one rear wheel. They are low drain, not coreless, and exceeding powerful.

The higher ratios are more suited to vehicles than the Portescap. The gears are made to very similar standards.

 

Stephen.

Thanks again Stephen,

 

I've taken your advice and bought one..... It'll certainly be smaller... I can't believe how much I'm learning about here - it's great (but a bit alarming as to how much the world's moved on...)

 

Thanks again!

 

Giles

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http://www.technobots.co.uk/acatalog/Shop_Front_Plastic_Bevel_Gears_402.html

 

Reference for 2mm shaft 1:1 bevels for the rear axle? These would allow the motor to be under the bonnet , with a 2mm drive shaft to the rear axle, solid, with one wheel "loose", they are 12mm dia, the black ones half way down page. With the gear box and 1:1 the speed would be perfectly controllable, you do not want scalextric speeds! ..... plenty of other interesting items on this robotics site.

 

Stephen.

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I've built up the front axle (fairly crudely, but successfully) and mounted it on it's front plate

 

IMG_6439-Copy.jpg

 

It's not got its track rod yet, so the wheels point in any old direction. The fiddle has been making sure the wheels are in exactly the same place as they were on the original - i.e. same spacing apart, same position front-to-back, and giving the same ride height. anything different will give the game away!

 

IMG_6443-Copy.jpg

 

As you can see, the wheels happily steer (though not together, yet). I've got a beautiful micro servo to do the steering, and I'm in the process of organising a receiver and bits and pieces (thank you Stephen), so it's coming on....

 

IMG_6445-Copy.jpg

 

The front axle is articulated so it will always keep all four feet on the ground.

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That's quite impressive.

 

I would like to have a go with servo's to make some loco parts work but need a bit more confidence building them first.

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Yes, that is very impressive indeed. B) B) B)

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Stumbled onto this by accident! What a great concept. I have already bought a cheap RC toy car with the idea of butchering the chassis from it into a diecast 1:43 Morris Oxford or similar. Not sure if the weight of the diecast model would overpower the toy motor though. Worth a try just for a laugh really.

 

Keep this thread going - I am currently building a small Gn15 diorama and I have 1:24 Bedfords I could use for RC - that would be a neat trick for shows!

 

Let us know what you use for control - I am completely hopeless at electronics but want my layouts to have more interest than just an occasional locomotive movement. Now that we have the beautifully detailed rolling stock I think it is about time we had equally realistic road scenes to complement.

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