Questioneering

Small progress update

Tried some different gearing on the tank this weekend, using Mecanno cogs to double the input speed to the gearbox, the idea being to make the tank twice as quick.

Sadly, there's not enough torque in the engine to make smooth turns with this arrangement, so I've decided to revert to the original 1:1 engine to gearbox ratio. No Speedy Gonzales for me, by the looks of things.

Also, I've noticed that there's quite a lot of oil in the steam exhaust, so I'm going to fit a Condenser to clean up the steam output.

It works! Very slowly!

I got the prototype running over the weekend, using a combination of Meccano and dodgy soldering. It's clear that the current power plant isn't going to cut the mustard. The boiler and engine combo don't have enough puff.

It's not surprising as the model weighs in at 3.5 Kg. I've ordered a marine engine plant from Regner, which is much more powerful. It runs at 45 psi, rather than the 15psi of the Mamod/Wilesco combination. The Regner is a flue boiler, with firetubes running through the centre of the boiler, wheras the Mamod's not much more than a tube with flames under it. Hopefully the combination of Germanic power and Japanese precision engineering will see me right.

Still, it proved a point, now to build something with a bit of poke.

Getting ready for the prototype

I've completed the renovation and alteration of the tank base. Changes include cutting down a couple of protruding driveshafts and cutting a slot in the base to allow the use of cogs to try different gear ratios from the engine to the gearbox.

Over the weekend I'm going to try and get a basic prototype up and running.

Checking the power plant performance

I bought a Wilesco D49 marine steam engine, complete with boiler and a Mamod SE3 from eBay. Over the weekend I fired them up to see how they performed and make the decision on what to fit to the tank.

The D49 boiler is very compact, but it's just not capable of providing enough steam to power the engine continually, which is disappointing. Thinking about it, I assume that's because when it's fitted in a boat for quite a lot of the time it's not going flat out.

Connecting the SE3 boiler provided much better results, with a strong flow of steam that really made the engine fly. I'll be going with the SE3 for the tank, the D49 boiler will be appearing on eBay.

I have to improve my plumbing technique, however. I soldered a pipe too close to the firebox on the SE3 boiler. The result, the solder melted due to the heat and the joint flew apart as it was under pressure. Steam and hot solder went all over the place.

I was sensible enough to be sitting a good distance from the boiler during the tests, so no harm done. If you're going to attempt something like this I suggest a good pair of safety goggles and healthy caution are things you should be using.

Tank renovation on Flickr

You can see how the work progresses in my Steam Tank flickr set. You can find it here.

First part, first problems

The advantage of the old Tamiya tanks is they have a metal chassis, so they are fireproof. The disadvantage is they are old.

All I can say is that if I outbid you on eBay for a "ready to run" Tamiya Leopard tank you had a close escape. I temporarily connected the motor to check the tank, and immediately one of the idler wheels (they sit at the front, off the ground) split, throwing the track. Bugger.

Next, I noticed that although the tracks ran forward, any attempt to steer ground the tank to a halt. One of the clutches wasn't disengaging. A total stripdown revealed a damaged shaft (pictured). Fixable, but only after a lot of faffing.

I've managed to get an unused gearbox from eBay in Holland at a good price, so I think I'll use the one originally fitted in the tank as a parts donor.

The plan now is to strip down the tank and renovate all the parts, and in the mean time start work on the steam side of things.

To bake your tank you will need...

Before embarking on construction I emailed I-Wei Huang, the guy behind Crab Fu, to get his advice on what was involved. I thought following one of his designs that I'd seen to work would be sensible. There will be plenty of problems to sort out even with a "proven" design, no doubt.

I-Wei wrote back quickly (thanks very much!) and gave me plenty of advice. I've decided to go with:

• An old Tamiya tank base for tracks and steering. They have a single drive, twin-clutch gearbox that should make hooking up an engine reasonably straightforward
• A Wilesco marine engine and boiler. Marine engines are the right choice because they can be stopped, started and reversed without having to physically spin up a flywheel first.
• A Mamod SE3 as an alternative boiler, because they are high output and have a superheater, in case the Wilesco boiler can't keep up

Most of this will come off eBay I hope. There seems to be plenty of bits and pieces, plus there's always the excitement of opening the box and hoping the item description hasn't been given the Estate Agent treatment.

Whatever I don't use will either go back on eBay or form the basis of the next project if this one's a success.

Seeds of an idea

I loved radio-controlled models when I was little. When you're thirteen there's something magic about driving a small car at high speeds, scaring the local cats and dogs and figuring out what you can jump over or off.

I was also fascinated by steam engines. My next door neighbour had a scale steam locomotive that was powerful enough to pull 4 people round a local track at quite some speed. Me and my Dad would go and watch and on occasion I got the chance to drive it, which was great.

These memories have lain dormant for years, but I recently had an overdose of Fred Dibnah, courtesy of UKTV History. This clearly tipped me over the edge, and I bought a couple of Wilesco traction engines, a  D405 and D365. They're fine, but lack a certain something, and RC cars are far too fast to be enjoyed where I live because open space is limited.

Combining my enjoyment of steam-power and radio-control seem the logical thing to do. Obviously.

What was I thinking?

The internet's a terrible thing. One minute you're noodling around, the next you've seen this and you've had it.

Something about the sheer pointlessness of these things means I'm compelled to have a go at building my own version. I'll write up my progress here.