Radio Controlled locos, lorries, cranes etc. Electroplating

[PhilJ W]

Very cool - it's got me looking at 1:43 Unimogs now!  Do you think it would be possible to do a 4WD one, Giles, based on your experience so far, or would that be pushing it a bit?  I realise it would add a lot of complication to the front axle.

Would you need four wheel drive? With a single motor you would require 3 differential gears. Perhaps a motor to each axle would be less complicated. If you wanted to drive the steering axle you could do worse than follow the prototype and have what is known as 'portal drive' where the axle is higher than the wheel hub. The drive from the end of the axle is taken through 90 degrees via a bevel gear to another bevel gear 90 degrees to the wheel, the vertical shaft holding the bevel gear acting as a king pin on the steering.

[Pugsley]

The only reason I thought about the 4WD was because I planned to use it as a road/railer for shunting wagons.  Having thought about it a little more, if it was sufficiently weighted it could be OK as the rubber tyres will be running on the rail surface, giving increased traction.

 

I guess there's only one way to find out!

[Giles]

Hi Martin,

 

I'm sure somebody has done it.... ( a viable 4 x 4, I mean). It would not have a diff, but a centre motor, and you would have to rock the front axle using the motor shaft as the pivot, I would think.....

However, a 4 x 2 should be fine for your application, and there are some fine models out there!

[Pugsley]

Thanks - it's probably just me trying to over-complicate things, as usual   I've identified the Unimog I want and set up an ebay search for the same - it's looking like the start of a slippery slope!

[PhilJ W]

Thanks - it's probably just me trying to over-complicate things, as usual   I've identified the Unimog I want and set up an ebay search for the same - it's looking like the start of a slippery slope!

I've got a couple of 1/43 scale Unimogs going spare, they are the Cararama ones of the current style. PM me if you are interested.

[Giles]

Here's two links - both 1:43, one showing someone else's drive train and steering method, and the other - a Unimog 4x4!

 

 

 

 

 

[TimC]

I've got the RC bits lashed up and all working. 

 

 

Binding the the receiver (I used a DT Rx43d-2-v5) and the Blade transmitter (picked up as a spare from Midland Helicopters, £20 plus P&P) was just a case of simply following the instructions.  I'm very impressed with the precision of the control and those little motor gearboxes are very torquey - I'm now planing to use two of them in 7mm Ruston 88DS 4w shunter I'm going to build.

 

The tape on the motor shaft was there so I could gauge the actual speed (32rpm with this particular battery) so I can calculate the road speed of the vehicle.

 

Hopefully, postie will not be too long with the lorry and then I can move onto the mechanicals.

 

 

 

 

[Giles]

Excellent stuff! You'll have that finished by the weekend then.......

 

We'll have to organise a Rally......

[TimC]

Excellent stuff! You'll have that finished by the weekend then.......

 

We'll have to organise a Rally......

 

 

Giles

 

Thanks!  However, this is my club project so I'll only get to work on it on Tuesdays - I've got other home projects that I must crack on with at the moment.  I'm hoping my mate Jim ('Flubrush') is going to give me a hand with some machining on the steering blocks so it'll depend too on how that goes as to the speed of completion. 

 

Yes, we'll certainly meet up at some time and try to avoid getting crushed by Pugsley's Unimog!

[Giles]

The steering/stub axle blocks, I just used some 3mm mild steel flat, drilled two 2mm holes through (for the stub axles) then hack-sawed either side to form a strip of 'block' which I then cross-drilled 1mm the other way for king-pins before cutting to size - so a small pillar drill, but not much precision there.

 

Just say if you need any photos or anything.

[Guest Natalie Graham]

 It would not have a diff, 

Why not? Ball differentials are used in the excellent 1:43 Kyosho dnano R/C cars and are available as spare parts, as are after market alternatives from other manufacturers. 

[Giles]

Are they....? Do you have any details, by any chance? When I was looking into it, I couldn't find any diffs that small.

 

It's not been an issue- performance wise - but if one can get them, it could be great to incorporate them.....

 

Thanks,

 

Giles

[Giles]

I've just found them and had a look - I had no idea that a company were producing such well engineered race cars in this scale!

 

The diffs though are quite large in diameter, and configured to site at one wheel, with motor drive directly to the outer ring of the diff, which may be fine for a modern car (if the wheels are big enough) but less appropriate for a period vehicle.

 

I'll certainly stick with the simple for the moment, for this application - but here's a link to a very informative page.........

 

http://www.kyosho.com/eng/products/rc/detail.html?product_id=109031

[TimC]

Well yesterday was a productive one down the club.

 

I made up a battery charger for the LiPo batteries.  Its a very simple circuit (purchased as a kit off eBay) which I've adapted to give a variable maximum current output and I've also added a meter so I can ensure that I don't 'cook' any of the batteries.  It just needs 5 minutes with the label machine now to finish it off.

 

 

The steering blocks didn't take too long to fashion from 5mm square brass.  I'll solder them all together with solder cream and a quick blast from the RSU and trim down the pivot posts to a shorter length.  I'll leave the steering horns off for now so I can play around with these to see what works best in due course.

 

Giles used shouldered bearings and I've some on order (from China) so they'll take a bit to arrive so I'll just go along with these plain ones for now.  At this stage, I'm not really fussed if I find that I need to remake these parts - its all part of the learning curve.  After all this is just a test build as I model BR Blue era (early 1980s) so I'll get this one sorted and keep an eye out for a more suitable vehicle for my era.

 

 

The lorry is a tad bright and I don't really like the 'body' on the back.  I'll get the mechanism sorted then worry about the cosmetics but I've got some BR Maroon and BR Green in a Life Colour paints pack that I've got no other use for so I guess it will end up one or the other.  

 

 

My motor/gearbox that does 32 rpm equates to around 3.5 mph so I've ordered a faster motor to give me 10 mph - should be plenty for layout use.

 

Next week, I'll start disassembling the lorry and beefing up the wheels to take the bearings.  Its the Club AGM next week so I'll only get the morning but watch this space.....

 

 

[Giles]

Lovely neat job on those steering blocks (much neater than I did!). I used a 6v motor with 100:1 back end which did me (operating on 3.7v) what ratio have you chosen, Tim?

 

Incidentally, you'll have to 'break off' the spare wheel carrier to get at the rear load bed fixing screw. I then drilled out the remaining plastic sprue in the locating holes (you'll see what I mean) and replaced it a with bent brass wire 'u' to hold the carrier and wheel in place afterwards.

[TimC]

Giles, the motor was allegedly a 6V 100rpm but I doubt it (!) so I've ordered three others - all 6V one each at 300rpm 400rpm and a 540rpm.  The 1970s era Mercedes truck I have my eye on has smaller wheels than the Ford Thames so I'll need a faster drive in any case. 

 

I've got this right haven't I?

 

32rpm on a 3ft diameter wheel (ish) - 32rpmx3.142(pi)x3(2r)x60(minutes)=18097.92ft/h; 5280ft in a mile; therefore 3.42mph

 

This afternoon while waiting for some information for some work I was supposed to be doing I had a read of the MLP2DSM transmitter manual (as supplied with some indoor helicopter) and I must check that mine isn't set to 'low' responsiveness (press down hard on the right hand side lever - similar to the action to bind the receiver which uses the LHS lever).

 

Thanks for the tip regarding the load bed, I haven't yet had a good look on how it comes apart.

Edited March 6, 2013 by TimC

[Giles]

....it's too late at night or me to work it out, but my recollection is that you should expect something like 130rpm out of 1:100 unit....... I wonder if either the ratio is wrong, or they've sent you a 12v motor by mistake? (I worked mine out to give me a speed of around 15mph. I did try a 1:75 unit, but it was a bit too fast)

 

Don't worry about the 'low responsiveness' on the stick - it resets itself each time, and you have to deliberately press it down to activate it for each use.

Edited March 6, 2013 by Giles

[TimC]

.t....... I wonder if either the ratio is wrong, or they've sent you a 12v motor by mistake? ....

 

Don't worry about the 'low responsiveness' on the stick - it resets itself each time, and you have to deliberately press it down to activate it for each use.

 

I think you maybe right regarding the 12V and I did wonder whether the transmitter reset itself.  Anyway, we'll get there in the end, at least I've spotted the issue prior to installation.

[Giles]

These are the ones I use (this is useful, because it shows a bit more data than other sites)

 

http://www.technobotsonline.com/pololu-100-1-micro-metal-gearmotor.html

 

And the same site has the bevel gears

 

http://www.technobotsonline.com/mini-plastic-bevel-gear-33527.html

Edited March 7, 2013 by Giles

[Guest Natalie Graham]

So who's going to be the first to build a 'Sunday Engineering Work' layout with no trains running but a fleet of radio controlled 'replacement' buses? Are we seeing the first signs of what happened to the real railways happening to model ones with trains being replaced by road transport? 

[Giles]

Why do you think my layout was called 'The End of The Line'......? :-)

[TimC]

These are the ones I use (this is useful, because it shows a bit more data than other sites)

 

http://www.technobotsonline.com/pololu-100-1-micro-metal-gearmotor.html

 

And the same site has the bevel gears

 

http://www.technobotsonline.com/mini-plastic-bevel-gear-33527.html

 

Hmmm, your 100:1 ratio is supposed to give 120rpm at 6V - which you would think would be about 80rpm at 3.7V so say 8.5mph scale speed.  I got my motor off eBay so I'll have to test it at 6V and then maybe 12V to see what speeds I get.  I suspect it isn't the spec as described.  I've got a growing list of projects I want to try with these motors so I'll find a use for it no doubt.

 

I got my bevel gears from Technobots too - dangerous website that - lots of interesting looking stuff.......

[Guest Natalie Graham]

It does make me wonder though, whether a fully scenic model road vehicle layout could be as interesting and entertaining as a model railway layout, or if it needs the trains? Do railways have something about them that wouldn't be there if it was just road vehicles?

[TimC]

So who's going to be the first to build a 'Sunday Engineering Work' layout with no trains running but a fleet of radio controlled 'replacement' buses? Are we seeing the first signs of what happened to the real railways happening to model ones with trains being replaced by road transport? 

 

If you get the RC road vehicle bug really bad then you could take it a stage further and model a typical goods yard in the 21st Century....i.e. a supermarket!

[TimC]

It does make me wonder though, whether a fully scenic model road vehicle layout could be as interesting and entertaining as a model railway layout, or if it needs the trains? Do railways have something about them that wouldn't be there if it was just road vehicles?

 

 At the Thornbury show most years there is a bus layout - the kids love it!  It works on a derivation of the Faller system though so it is not RC.