Class 22 Diesel (next project)

Although I am still working on the 0-4-0 loco I have in between jobs given some thought to my next project a Class 22 (baby warship). The 0-4-0 is a test piece really and my first attempt at a 5 inch loco, its not a model of any real loco but more a fun model which I hope will pull 2 or 3 passengers. The class 22 will be semi scale and hopefully a reasonable representation of the real loco.

A grubby and well used Class 22.

Early days but a sketch below of how I may approach the build of the bogies and drive assembly. The loco is twin bogie with four axles all of which will be driven. Apologies for the state of the sketch but hopefully it shows how the axle/motor frames pivot on a shaft mounted across the centre frame. The axle suspension is via springs mounted to a pair of bars, a fixed bar between the axle frame sides and a pivoting bar mounted to the centre frame.

Nothing is set in stone, just ideas at the moment.

Ron

As you will have more space to play with you might want to look at raising the motor up and also using chain drive to get the mechanicals clear of track debris.

Posted by Ron Laden on 12/08/2018 09:57:59:

 

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Classy sketch Ron! Is it the result of training or natural talent? Although designing on squared paper helps me think my efforts on squared paper are far less artistic. Too often I go straight from 'back of envelope' to CAD as a way of reducing the embarrassment!

Another point - although CAD is brilliant in every other way I find the drawings lack personality compared with those made by a draughtsman on an old-fashioned board. Producing good looking drawings is part of the hobby's attraction for me.

Dave

Edited By SillyOldDuffer on 12/08/2018 10:38:25

Thanks Bazyle, you have told me before about track debris, the club track is raised and I was assuming it would be cleaner than ground level track but I will take a look at it. I would rather stay with gears if I can plus there is a limit to how far I could raise the motor without it clashing with the upper chassis/batteries etc.

Ron

Thanks Dave, the last time I did any technical drawing was back at school which was a long time ago. I just find graph paper easy to layout, I would like to be able to use CAD but I fear I would be hopeless at it and can probably finish a drawing (good enough for me to work from) quicker than I could manage a couple of lines on CAD.

Ron

Is the track steel? 'Debris' will be mostly rust and it forms afresh every week. At the club we run the passenger trolleys round during the starting track inspection to take off a bit of the new rust before the first loco goes round. Aluminium track will be less dirty.

Its steel track Bazyle.

Working from a scale drawing of the class 22 loco I have put together some dimensions and figures for a 5 inch version.

Overall length: 48 inches.

Body width: 9 inches.

Height: (from top of rails to top of body): 13 inches.

Weight: (including 2 x 12v / 75amp leisure batteries) estimated 65 kgs.

Gearing: 6/1

Power: Will depend on which motors I go with but the ones I am leaning towards will produce approx 1000 watts (1.3 hp) across 4 axles. Seems high I know but I am hoping to carry 10-12 passengers and thinking that its better to have too much than not enough, plus I think it will need reasonable power for pulling away with a full load of passengers.

Speed: 7 - 8 mph (max)

Well thats about it for now, I had better get back to the 0-4-0, just about to start building the body.

Ron

Edited By Ron Laden on 13/08/2018 10:26:01

I doubt you will need that power full time, but in any case, don't waste money on leisure batteries and get proper traction batteries, - high current AND deep discharge.

Neil

I thought that leisure batteries deep discharge but obviously not.

Thanks Neil

Ron - You may already know but the Project Class 22 Society who are aiming to build a new class 22 have a side elevation of this loco on the homepage of their website.

**LINK**

Edited By Nick Clarke 3 on 13/08/2018 11:08:33

Hi Nick,

Thanks for the link and the side elevation is useful it shows some good detail.

To be honest I didnt realise there was a society intending to build a new 22, that is some undertaking and I will keep my eye on progress.

Regards

Ron

I dont know if I am looking in the wrong places but 12 volt traction batteries are expensive, or at least the ones I,ve seen are, didnt expect them to be those sort of prices.

Good news - batteries are a technical problem that's easily fixed. Bad news - the solution involves the owner having deep pockets.

Car batteries are cheap because there's a massive market for them. Regrettably being used for leisure or traction kills them in short order. A leisure battery is optimised for an entirely different charge / discharge cycle and they don't last long in a car.. Nor do they perform well as traction batteries. The right battery for each scenario performs better and will be cheaper in the long run.

Sod's Law being what it is, your loco needs the most expensive type available. Welcome to model engineering...

Thanks Dave,

Oh well, traction batteries it is then, I had better start saving..

Ron

Could look at a fuel motor or 2, maybe a scale diseisel one?

Roger

Are you really going to use the loco that severely. The batteries in our club Compass House 08 shunter are just car batteries I think and are years old. When I was looking after it we used it for an hour or so until there were too many steam locos on the track and the batteries always recharged in an hour or less on a Halfords automatic charger. I never did a scientific assessment of the amount of discharge but the feeling was it hardly used any juice. The track is flat and we weren't pulling silly amounts of passengers.

Edited By Frances IoM on 13/08/2018 23:19:37

Ron,

I built an 040 with a single Sinclair C5 motor, tooth belt reduction to a countershaft and then chain drive reduction to both alxes. Controller was a DIY kit MOSFET controller as it was a budget project for the kids when money was tight. I used an old car battery from the family car that went to the scrap yard, never had any bother with it, used to pull the 3 older kids on a club driving car all afternoon on the club 720' raised track and later was used on a ground level portable track at fete's and pulled 4 kids plus a driver up and down 100' of track all afternoon, never went flat enough to stop operations. Maybe car batteries were better built 20 years ago! Since the kids grew up its not had much use, the last battery it had when the original car battery finally expired was a UPS battery I 'inherited' through work, never had a problem with that either. Yes I think the advise that traction batteries should be used is technically correct but for what we do I don't think they are essential. Even now I have an ex caravan battery that was superceded from its original duty running the winch in my trailer to pull the traction engine in and out, gets charged once a year and so far has never let me down, my dad used it for a couple of years or so and I have used it for 10 years since, no idea how old it actually is but when winching in it pulls a fair amperage dragging a 4" scale engine up thirty degree ramps.

Paul.

Thanks guys,

After Neil suggested traction batteries I did quite a bit of reading yesterday on the different types of batteries, Yuasa have some very good technical info on their site.

From what I read it is quite clear that deep cycle (traction batteries) would be the way to go. They can deliver high amps and the capacity can be taken down to quite low levels. It would appear that the same usage would shorten the life of a car or leisure battery, the leisure battery less so than the car type. If I understand it correctly the key is how low the capacity is taken down. Deep cycle batteries can be taken down to 30% whereas car and leisure batteries would suffer if regularly taken down to those levels.

I have to say that I have seen car and leisure batteries powering electric locos, probably more leisure than car. I never thought to ask how much capacity they take from the battery and if the batteries have a long life I just assumed they must be fine.

Bazyle, "Am I going to use the loco that severely" no, far from it but I want a loco that has good performance i.e. a reasonable top speed and not too pedestrian but I am not looking for a rocket ship. Also with "silly" numbers of passengers it would be good to have a loco that can pull away from a standing start without the need of a push which I,ve seen on a couple of locos.

Ron