Radio controlled road vehicles on Upper Benllech

[otherplanet]

Some progress with the CAD and the build.
I have now CAD modelled the complete vehicle, printed everything and put them together as a dry run.

Some of the smaller detail parts are still on the bench (steering wheel, gear levers, tail light) and there are others which will be made from scratch. The grills over the large open sections at the rear will be cut from etched mesh, which I need to get around to ordering soon. I did print the starting handle, just to see how the printer would cope, It came out beautifully, but its far too flimsy to survive and the final one will be made up from wire.

 

There are still bits of fettling to do, some of the print supports have not been fully cleaned off for example and nothing is glued, just pressed or clipped together, the front dashpanel for example is just pressed into a tight fit pocket, and the windscreen is held on mostly by wishful thinking.

 

The front suspension has come out particularly well. I found some model rivets online in 0.3, 0.5 and 0.8mm diameter. So have designed the front axle to make use of these. (the 0.5 specifically) these are a great improvement over bent brass wire, firstly they are a spot on 0.5mm, so with a matching drill, I get a nice tight fit on the static side, but a little extra work leaves the moving joint nicely running. The head of the rivet seems to hold well and looks much better.
As mentioned above, the printed steering knuckles proved much stronger than I had hoped, I designed them to be cut from brass channel, but after such a promising print, I have amended the design to add some bosses around the bearings and stiffened it up a little more. 
The front wheels have a short length of 0.7OD brass tube inserted into the hub, and the 0.5mm rivet is then passed through this, through a M1.0 washer and then glued through a boss in the knuckle. 

 

The track rod will eventually be clipped off under the joints, but not until after painting. (the assembly is resting on a set of wide blade tweezers to stop it rolling away.) The two bosses on the top of the axle are for the compensation mechanism, the one at the rear is an optional feature to connect the coupling bar to that runs to the rear of the vehicle. This should be connected to the rail bogie, but I am allowing for some trials to see what works best in model form. (this is the back up plan)

Over all, I am really pleased with this assembly, the wheels run smoothly and the knuckles turn freely, but there is negligible slop.
I am also very pleased with how the more subtle details have printed.
The embossed ribs just behind the cab and around the dash panel look good despite being very small, only about 150um tall for the concentric squares.
but the makers plate and headlamp aperture covers on the front have lost definition and don't really stand out, I will probably tweak the model and re-print this part.

 

The structures inside the rear of the engine bay are to clip a servo into. Most of the photos of the prototype show this space as being fairly empty although I think the radiator and cooling system was in here. The coarse mesh grills combined with 1920's photo editing also obscure what little detail there was, but I am sure it will be more obscured in the model, however, the servo should allow the coupling to work.
 

Some of the photos of early versions of these guy tractors at had a hinged buffer beam at the rear, that looks like its intended to allow some basic shunting, probably when the vehicle is in road mode (it cant reverse properly when in rail mode as there is no steering.)
I did attempt to model this as well, it printed beautifully, but I could not open up the holes in the brackets on the rear axle that it hinges on and the buffer is just too flimsy. (photos of the prototype one suggest they had a similar problem and its not seen in most photos so I think they gave up with it.) I will upscale it a little and make it from metal, and attach the brackets as new larger seperate parts. as I am hoping it will work well enough to keep the 'hand of god' off the model. in which case it will be worth the modeller's license

Next steps are to get the motor, gears and steering servo installed. This is mainly waiting on the gears to arrive for the drive train.

 

I also need to decide what colour to paint it. I have not found any reference as to the colour of these early vehicles. The company changed colour scheme to a dark green with the introduction of the later Beardmore steam tractors for the official Wembley tourist line. But these Guy tractors were much lighter in colour.
If anyone knows anything please let me know, I will also ask in the Questions section on the forum.

Edited April 16, 2022 by otherplanet
Replaced lost photos

[Giles]

Stunning.... simply stunning!

 

I've finally got into my Mars 2 Pro  and am finding my way with that, and loving it - but this takes it to a new level!

[PhilJ W]

As for the colours I have the book on these vehicles that you mentioned. I notice in one of the illustrations in the book at least one vehicle has panels in a different colour to the main part of the vehicle separated by a lighter coloured lining. Seeing as there seems to be no record of the colours of the vehicles you might as well apply rule one and paint it in a colour of your choice. (I personally would go for gamboge, a very bright yellow that shows up as white in old B&W photographs.)

Edited March 13, 2022 by PhilJ W

[otherplanet]

Thank you both.

I am pleased with the progress.

 

PhilJ W. Do you mean the picture on page 10? I suspect the dash panel in that photo may still be in grey primer as they appear to have not finished building the cab.

 

I quite liked the idea of yellow, although probably more ochre as looking up that gamboge it sounds rather expensive. I know that the Edwardian tastes were sometimes quite garish, as characterised by the range of pre grouping liveries. But if that panel is grey, then it suggests the proper paint job is a darker shade.

 

Ultimately you are correct. rule 1.

Thank you

[PhilJ W]

The actual photograph that I referred to was of the Beardmore-Sentinel on page 34. What appears to be a darker colour in some photographs of the period could actually be lighter, reds in particular often come out as black. This was due to the the emulsions used.

[otherplanet]

Ahh. I understand now. Thank you

[otherplanet]

So, disappointingly, the gears I ordered from kkpmo have failed to arrive. They initially sent someone else's order and after several emails to get them to answer, they agreed to resend the correct parts, but still no sign of them, and its all gone quiet on the email front.

Which is all rather frustrating as apart from the cost, some are sizes not available from other sites like Sol-Expert.

Whilst considering whether I can find a ratio I can buy without having to change the currently printed chassis, it occurred to me to try printing a set of gears. Its something I had planned to try at some point anyway, so time to give it a go.
Searching online for guides on modelling gear profiles, I discovered that Onshape (the CAD tool I use) has a gear profile function to download, so creating the models was really easy.
I have added a flange to the rear face to give something for the support structures to attach to.

I also printed a test plate with stub axles to test them on.

Shown in mesh are 10tooth, 15tooth and 14tooth Mod 0.2 gears.
The profiles are pretty good, but 'very' slightly over sized, the 14 and 15tooth gears are on axles that are 0.1mm further apart than they should be. But otherwise, these were slightly tight to start with but ran in quite quickly. They are as printed except boring out the hole in the middle.
The gear to the left is 14tooth but with a 2mm hole to fit directly to the output shaft of the 6mm gear motor.

I am sure these will not be as strong as proper acetal gears, but they certainly run OK to start with.

 

Having built them into the chassis, they run well enough for the tractor to drag itself and a trailer with the receiver on it around. (although the drive wheels have very poor traction, being hard plastic with no plasti-dip on them).

They are showing a little dust on the teeth after running for a bit, its not clear whether this is just from running in, or will continue to deteriorate.

I have since tried a slightly different design that I can sand the flange off after printing, Which will allow me to get the maximum length of gear for maximum strength. I intend to try these shortly, with a bit of silicon grease to minimise the wear and then see how long they last on a life test.

 

Either way, this definitely works as a method of assessing a chosen gear ratio before ordering proper parts.

 

I did try to make some videos of this first run, but they didnt come put well, so I will have to try again soon.
However the next step (before life testing) is to get the uncoupling system working properly.
The rail uncoupler works, but the tow hook for the road trailer is still fighting me at the moment, it needs a bit more precision and planning to get the rather close dimensions to work properly

 

Assuming I can resist the temptation to try building a differential!

[Giles]

Annoying that you've had a problem with your kp gear delivery. I ordered some a month ago, and opted for their cheapest delivery (£4 ish) and it did arrive - though it took 4 weeks....

 

Presumably your using an ABS type resin for the gears?

 

A diff would be fun! I did a couple as tests - one went into the forklift - but nothing this small!!!

[otherplanet]

As usual, its taken some time to make progress. Mainly due to other distractions, but particularly because the uncoupling mechanism has been really fighting me.
I'm still not happy with it. the rail uncoupling works well, other than it doesn't retract far enough into the body when its finished. Which means it then gets in the way of the road tail hook.

Also the road tail hook is pushed down by the servo and is then sprung open, which means if the trailer is only partially engaged, it tries to break the servo out of its mount, which is a shame because otherwise it works beautifully.

I will attempt to improve it for the next one, but its held up progress for too long. So I intend to pause it now and move on to test other aspects.

 

Anyway

Here is a short video, please excuse the manual handling to push it back and forth. With no weight inside, smooth hard tyres and big fat wires going to the external servo, it doesn't self propel to any useful degree yet.

 

[Giles]

Lovely!!!

[otherplanet]

Its been a while, as usual.

All the hard work on the uncoupler proved fruitless when the battery proved to be slightly bigger than I had thought (should have measured it more carefully.) So the uncoupler has been removed and the receiver, wiring etc all installed. 
I have also detailed up the cab, added a driver, the grills to the back and some paint.

 

After a little running in, it is now pretty smooth and I am very happy, the 3D printed gears are currently holding up well, but time will tell. The steering has a little too much travel so the front wheels can catch the chassis on full lock, but they turn smoothly and precisely. I am not happy with the front compensation which has sagged and doesn't compensate, so the front is a little too low and it waddles over bumps.
There is still much detailing to add, from the crank handle to the tail light, number plates and some light weathering.

Colour was selected after a lot of online discussions, review of the photos and discussions with some people who have spent a lot more time studying the prototype than me. One mentioned a memory that the Stronachie tractor was described as yellow or lime green. Given that Yellow Oche was a common, low cost colour at this time and the whiskey industry is obsessed with the colour amber. I decided to go with that for the body, the early photos show the wheels and axles in a much darker colour, and I think the brown contrasts nicely. I am still not sure whether the roof shouldn't be white. Its almost invisible on the photos, I am a little concerned it might look too 'Stroudley'.

 

The big glowing light in the back is the status LED from the RX43 receiver, it will need to be covered over, but not until the tail light is fitted to substitute as the feedback. Until then it will have to look like there is a fire in the engine bay

 

[Giles]

So, a few minor tweaks still required - still, stunning work! (As usual)

 

Always good to see!

[otherplanet]

Running on rails is an important aspect of whether this is usable. So I have started a small test track / running-in circuit. 

Of course as soon as the first decent section is laid, it needs to be tested to make sure the I haven't messed up on the min radius or gradients. 

I have used very fine N gauge ballast to represent the roadstone set into grooves pressed into the Das clay on the outside of the rails. The video on BFI showed the sleepers were covered between the rails but only by a shallow depth of soil leaving a relatively deep trough.

 

The tractor seems to ride OK although the bogie snags on the slightest obstruction and needs better quality bearings. 

 

I have now added home printed decals for the number plate, axle weight and speed limit plates and name plate on the front of the cab. I also decided the roof in the same yellow as the body just didn't look right, so I have changed it to white. Which feels much better, if a little 'Stroudley-esq'

 

[Chas Levin]

Hello, just found your thread and like lots of others, hugely impressed! I started reading from page 1 but there are lots of missing photos, presumably from the RMWeb outtage a while back? I wondered if you plan to re-load them? I know how much work's involved - I did it with mine - so I quite understand if not, but if you do, please would you post to let us know, as I'd love to see some of the earlier projects you describe.

In the meantime, very happy looking at your latest work!

[otherplanet]

Thank you for your comments.

Yes unfortunately many of my photos were lost in the great purge.

 I had left it in the hope that more would recover themselves. But I think that time has passed. I should go and replace them, but it never seems to float to the top of my to-do list. Part of the problem is several of them were cropped etc specifically on phones which are long since retired, and therefore don't have an exact matching file name to search for in my archive.

I will try to get around to it. But dont promise anything soon.

[otherplanet]

However. Here are a couple of the latest photos of the Road Rail tractor

This is now about cosmetically complete. I need to find a metal horn to go by the driver. something robust enough to survive contact with my fingers or a crash into the trees.
But other than that, I am happy with the weathering and extra details. At least until things progress significantly on other parts of the project.
I may yet go back and have another go at jacking up the front a little, its too easy for the wheels to catch the underside of the cab and then the wheel locks and everything goes sideways. 

 

 

and one in artistic black and white

 

 

[otherplanet]

I recently joined the East Bedfordshire Model railway society.

We were at the Stafford exhibition last weekend which was great fun. 

I took the fleet of lorries, they are mostly rather early prototypes for the layout. But it gave a good chance to dust off the old ones, and give the new ones a proper shake down and see how they worked.

 

Mostly things went OK..although the layout was never designed for the road vehicles to move, so the hills are steep. The yard is narrow and the gates glued with one closed, so only the K8 could leave the yard.

Never the less. I was very happy and there was much interest from the visitors.

 

 

[Giles]

Lovely!  I do like that rising tailgate on the Thornycroft!

[otherplanet]

My latest experiment is to try printing rubber tyres.

I have been wanting to try this for a long time, even before I had my own printer. However the price of prints from the printing bureaus that could do elastomeric materials back then were extortionate.

 

These days there is a broad range of flexible resins and I finally got to a useful point in a project to make it worth giving it a go.

Below is 2 sets of prints, the grey wheel hubs are my usual hard resin. The white are the corresponding tyres in Resione F39. (I haven't finished cleaning off the supports etc)

The F39 is described as a soft rubber like material, its a little firmer than I expected, but has printed very well. It doesn't show up well in the white, but there are features in the side walls and a tread texture on the circumference. The surface finish seems to be fairly grippy, I am using a set of EFE tyres as my point of reference and without resorting to a scientific test, they appear to have similar friction. Obviously friction is the key requirement here to ensure good traction,

 

I chose a white rather than a black or grey resin as for the older vehicles some of them pre-date common use of carbon black in the tyres. and even modern tyres aren't jet black, at least not on the tread surface. 
So my plan is to try some of the dyes that are available and see how good a colour match I can get.

If all else fails, there is an equivilent black resin from the same supplier.

 

The wheel hubs on the left are from the Stronach Dutton tractor, essentially the same model as I made for the original model, but with the tyre section removed. My hope is that these will make a better replacement for the current hard resin wheels painted in plasti-Dip.

The wheel hubs on the right are for some 1950's lorry's that I am working on for my club layout, my hope is that being able to make the wheels will give more flexibility in design. But also means I can shape them to suit the wheel bearings etc.

 

I will let you know how they perform, once I get something running

 

[Giles]

That is extremely interesting.  I didn't know you could get a resin like that. I have always used proper tyres on vehicles, or fitted neoprene rubber strips (on the traction engine). Being able to print useful tyres of any type or size opens the door significantly.

The only vehicle I have on hard plastic is the Austin Seven, which skits about a bit in consequence.......

 

Thank you!

[otherplanet]

A short video of the Guy tractor hauling my newly finished models of the 4 wheel wagons that ran on the Stronachie distillery tramway.

Unfortunately quite a bit of wheel slip, so still work to do. But I am very pleased with how they look as a set. 

This is running with the plasti dip coated wheels. I will run a series of tests and then convert to the new soft resin tyres and compare the performance

Edited December 8, 2023 by otherplanet
Missed an important detail

[otherplanet]

Further development work.

The tractor needs to mount and dismount from the rail bogie, so I have been trialling different ramps. It took a bit of debugging, but the dismount now works reliably 10 out of 10 times.

Remounting is much harder, mostly reliable if you manage to line it up within about +/-1mm left to right. Which needs more practice! 

 

 

The original ramps tended to slip around as the road wheels touched them. But adding magnets underneath gave enough grip for them to work. The magnets also mean the ramps can in theory be moved out of the way once the front wheels have passed, rather than bumping the rear wheels over them. Either by sliding the magnets under the track. Or tilting them by 90deg, which will cause the ramps to tilt on their sides. At least they work when I test by hand. I haven't tried building a mechanism to do it yet.

Either way. They are a bit chunky to be prototypically moved as each ramp is  basically 2 half sleepers glued side by side. But anything less requires exceptional driving accuracy and is too inclined to topple over with the  weight of a misaligned tractor.

 

Rubber tyres are still in development. Applying the recommended cure time left them hard, with poor friction. So I am running a trial comparing cure times. The best so far is slightly higher friction than EFE lorry tyres. But not as good as a rubber band. Not yet tried them on the RoadRails tractor.

[ColinK]

Brilliant, I never expected to see a working model of it.  For the remounting, perhaps ypu could put a flange on the top of the ramps, a bit like one of those plastic rerailling ramps, with the flange getting narrower and narrower until the pivot lines up exactly.

[Giles]

Stunning!

 

The only tyres I've added to a model was from neoprene to the traction engine, which worked nicely. I simply cut a strip and super-glued it to the wheel.