Jump to content
 

R/C Bedford TK Tipper 1:43 and 4mm ACE Ergomatic 6 x 4, 4mm Landrover


Giles
 Share

Recommended Posts

I've just completed the chassis for a 4mm scale (conversion) of the Oxford ACE Ergomatic 6 x 4 , as I wanted to try out a thought I had regarding driving both rear axles. I'm aware that you can buy a double axle gearbox unit from one of the European companies,  but that wasn't the point, as I wanted to see how practical the solution might be generally.

 

49997760993_bd508328d8_3k.jpg2020-06-12_03-15-35 by giles favell, on Flickr

 

 

Having completed it with all its wiring, servo and Rx, it taught me a couple of things.

 

  • Like 2
  • Craftsmanship/clever 1
Link to post
Share on other sites

I found that the 100rpm 6mm gearmotor that had proved adequate for the Borderer artic is not quite up to driving a double axle, and looses the slow start . I have replaced the 6mm motor with one of my remaining 8mm gearmotors,  and it now performs beautifully!

 

Because there are no diffs, if all three axles are absolutely flat on the ground, there is a tendency to carry on in a straight line- regardless of the steering. However, since it is rather difficult to achieve this in practice, it is likely that one of the rear axles will be slightly 'light, and it won't be a problem.

 

Meshing the gears on the intermediate shaft was a little bit of a faff, but it was doable. With Mod 0.3 gears, you can't afford to have too much play in the axles.....

  • Like 1
Link to post
Share on other sites

Very good Giles, it performs very well. I was surprised how well it moves in the video on a smooth surface without any differentials, fair play for making it a proper 6 x 4 rather than a 6 x 2

  • Thanks 1
Link to post
Share on other sites

  • 1 month later...

I bought a 4mm Land rover by accident from EBay, thinking I was getting a 7mm one! Rather than waste it, i thought id have a play, and see if i could modify the axles i use for lorries to a much narrower track  - and so i can......

 

 

 

  • Like 5
  • Craftsmanship/clever 6
Link to post
Share on other sites

  • RMweb Gold

I tell you what Giles, that thing's got a much better lock than the real thing :)

 

Long-wheelbase Land Rovers are renowned for having a turning circle approximating that of an ocean liner...

 

Al.

Edited by Alister_G
  • Like 1
  • Agree 1
Link to post
Share on other sites

9 hours ago, Alister_G said:

I tell you what Giles, that thing's got a much better lock than the real thing :)

 

Long-wheelbase Land Rovers are renowned for having a turning circle approximating that of an ocean liner...

 

Al.

That is unfair on the ocean liner...

  • Funny 1
Link to post
Share on other sites

12 hours ago, otherplanet said:

Lovely work as usual Giles. I'm sure you said 4mm was too small for you!

I wish I could keep up with even half your productivity

 

I did - but I found myself going down a rabbit hole......... having found a way I can make axle kits for 7mm, I wanted to see if I could make them for 4mm, and then could I make even narrower axles for 4mm..... etc..... (All on the laser cutter, with bearings on stub axles).

Then of course my favourite motors became unavailable,  so finding a reasonable substitute...... These 100rpm gearmotors are about £3.50 A piece, and perform as shown - however, when you tweak the transmitter (A Jumper TSG8 or whatever..) The characteristics get even better, and more realistic.

 

 

Link to post
Share on other sites

  • 1 month later...

It just all looks so big in there. Room spare for several more motors!

Seriously. It looks great and runs beautifully. Could you share some details about the new latest differential you have got in there.

 

Incidentally, during some research for future potential projects, I read that the Scammel 100 tonner of 1929 had 2 rear axles side by side so it looks from the side like a single long axle with wheels at the ends and in the middle. Each axle had a differential and then they were driven via chains from a central diff that split the drive between the 2 axles. So 4 wheels and 3 diffs. Possibly a little excessive for modelling.

Link to post
Share on other sites

I've actually just rebuilt one of my original diffs. This one has four Mod 0.3 bevel gear inside. One silver-solder to each drive shaft, and two in opposition loose on a fixed cross shaft. When all these are gently but fully meshed, you have your diff. The case is 9mm O.D. brass tube although with Mod 0.3 you could probably go down to 8mm O.D. the are turned end fittings with flanged bearings for the drive shafts, which push into the tube, and are retained with Loctite. 

You could of course use mod 0.2  bevel gears from Germany and get it smaller - though the gears are getting quite expensive!

 

That Scamell sound a nightmare!

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...