Electric Traction Engine

[JasonBModerator @jasonb]

The book is just the printed pdfs.

I have seen a couple of Minnies done with a "Sun and Planet" diff which is not so hard to do. However if you just want to go round and round the garden with the Grandkids one driven wheel will be fine

[Ron LadenParticipant @ronladen17547]

I am surprised if running on grass as I will be that you cant go with two driven wheels and no diff, I appreciate not good for tight manoeuvring but general running about with large radius turns..? Obviously not, which does surprise me.

[Jon LawesParticipant @jonlawes51698]

A solid axle isn't going to create an understeering death chariot surely. It's just going to slip a wheel, especially if the front axle has some weight over it.

[Ron LadenParticipant @ronladen17547]

I found the drive pin arrangement on the Minnie build looks simple enough.

[Paul KempParticipant @paulkemp46892]

Posted by Jon Lawes on 28/10/2018 14:07:49:

A solid axle isn't going to create an understeering death chariot surely. It's just going to slip a wheel, especially if the front axle has some weight over it.

John,

You would think so. However, have you tried driving a Maxitrak Avelling with both pins in, on grass or the road? Interesting is the only way I could describe it. Not a particularly large or heavy engine but it wouldn't go round any significant corner! Most conventional traction engines (exclude rollers, Showman's and Ploughing engines) do not have that much weight on the front end. Although Ron's is going to be a bit different the overall geometry / volume is the same so unless the batteries are right forward in the smokebox the effect won't be much different. I can't see any major disadvantage driving on one wheel. Especially if a pin arrangement is built in to allow the second to be driven if conditions dictate.

Paul.

[JasonBModerator @jasonb]

The other thing that makes them want to go straight on is massive grip from the straked rear wheels and a smooth steel strip as the "tyre" at the front. The American engines fair a bit better as they tend to just have a narrow ridge on the front wheels which bites better off road.

[Ron LadenParticipant @ronladen17547]

I will need to check my figures but a quick calculation of the gears at my scale and using the same number of teeth as the Minnie seem to work out size wise for the scale using the following.1.25 MOD (20DP) for the crank 1.5 MOD (16DP) for the mid and 2.0 MOD (12DP) for the final drive. I will be purchasing the gears as I am not tooled up for making them but they will need some modification on the lathe. The reason for going with MOD gears is they are 30% cheaper than the equivalent DP for some reason.

[Ron LadenParticipant @ronladen17547]

Paul/Jason, I,m convinced, I will drive on one wheel and build in the pin arrangement.

[Michael GilliganParticipant @michaelgilligan61133]

Ron,

There is another configuration which might suit your freelance design.

It roughly approximates differential action, but is much simpler.

Drive each wheel via a 'freewheel' unit [like on a bicycle]

MichaelG.

.

P.S. : reversing would, of course, require some locking arrangement.

[Ron LadenParticipant @ronladen17547]

Thanks Michael, that is certainly a thought.

After Jason mentioned the Sun and Planet diffs, I got the sketch pad out and I dont think it would be that difficult to build and I would think work quite well. Anyway its been added to the list of ideas.

[Howard LewisParticipant @howardlewis46836]

If you do not fit a diff, you cannot have both wheels fixed to the axle, unless you wish never to turn. It won't matter which way the front wheels face, the machine will continue in a straight line.

Years ago, I fitted a brake to out son's pedal tractor, on the opposite side to the driving pin. It would not go around corners. Years afterwards testing a 192 hp tractor, i had the same problem! I had inadvertently engaged the diff lock. The centre rib tyres ploughed nice furrows up the field.

So, no diff = only one driving pin; unless on slippery ground, and then back to just one when on better surfaces.

Howard

[Ron LadenParticipant @ronladen17547]

Thanks Howard, points taken.

Ron

[Ron LadenParticipant @ronladen17547]

Just out of interest were all full size traction engines fired by coal or did any use other fuels.?

[not done it yetParticipant @notdoneityet]

From Wiki:

“Solid fuel, such as wood, coal or coke, is thrown into the firebox through a door by a fireman, onto a set of grates which hold the fuel in a bed as it burns. Ash falls through the grate into an ashpan. If oil is used as the fuel, a door is needed for adjusting the air flow, maintaining the firebox, and cleaning the oil jets.”

[JasonBModerator @jasonb]

There were also a few straw burners made which had a modified firebox and a driven feed system. Really depended where the engine was being used, wood was more often used in the US and Australia and the straw burners on prairie.

[Barnaby WildeParticipant @barnabywilde70941]

Posted by JasonB on 30/10/2018 06:55:40:

There were also a few straw burners made which had a modified firebox and a driven feed system. Really depended where the engine was being used, wood was more often used in the US and Australia and the straw burners on prairie.

I don't know if it was ever used on traction engines but Marshall stationary engines burning rice husk are VERY sought after in the rice growing regions.

[Robert Atkinson 2Participant @robertatkinson2]

Posted by JasonB on 28/10/2018 16:44:21:

The other thing that makes them want to go straight on is massive grip from the straked rear wheels and a smooth steel strip as the "tyre" at the front. The American engines fair a bit better as they tend to just have a narrow ridge on the front wheels which bites better off road.

When going faster two ribs way be required

Yes those are the steered wheels at the back.

[Ron LadenParticipant @ronladen17547]

Thanks guys

I would like to add a differential to the engine if I can, so I have been looking at how and where it could fit in and I think I have that worked out.

However having never done anything with diffs I thought of how it could work on a one piece axle but I,m not sure I have got it right or even if it would work. I have attached a very simple sketch below which shows what I am thinking. I wouldnt mind if you guys can take a look and tell me your thoughts and more the point will it work. There is no detail there of the parts just the basics to prove its working or otherwise.

Thanks

Ron

 

Edited By Ron Laden on 30/10/2018 09:15:34

Edited By Ron Laden on 30/10/2018 09:17:42

Edited By Ron Laden on 30/10/2018 09:21:36

[Paul KempParticipant @paulkemp46892]

Ron,

That is basically the arrangement but! Where is the drive coming in? If you are going to drive onto the axle then I think at first glance that will work – as long as the wheel with its "sun" gear and "planet" housing is free to rotate on the axle.

However, your terminology is a bit mixed up there. What you have drawn with 4 bevel gears is not a sun and planet diff. A sun and planet set up would be a bit different to that using straight cut rather than bevel gears. So 'correct' terminology for the above would be crown wheels for those mounted on the axle / wheel and pinions for those mounted in the diff.

Also on a 'normal' (if there is such a thing) traction engine the pinion carrier / diff housing / or as you have termed it 'planet gear carrier' would be the driven component, the final drive gear being mounted on its outer diameter and it would be free to rotate independently of axle, wheel or anything else. The inner crown wheel would be pinned to the axle as you have it, the outer crown wheel fixed to the wheel, as you have it. Thus the diff housing would be driven from the second or third shaft and drive on the crown wheels via the pinions. The wheel being loose on the axle, the opposite wheel being fixed to the axle so the 'differential' movement imparted by going round the corner will be taken up between the two crown wheels.

Not sure I have explained that in a very clear fashion! Maybe Jason can do one of his CAD drawings which would show it better.

Paul.

[JasonBModerator @jasonb]

I was thinking of the 2 sun -2 planet type that can be done with just spur gears like this and this

 

Edited By JasonB on 30/10/2018 13:24:08

[Ron LadenParticipant @ronladen17547]

Thanks Paul/Jason, you will have to leave that with me for a while to see if I can make sense of it.

Ron

[Neil WyattModerator @neilwyatt]

Only on this forum will you find someone demonstrating a jet-powered car uses the same technology as a Case traction engine to keep it going in a straight line…

Neil

[Ron LadenParticipant @ronladen17547]

Posted by JasonB on 30/10/2018 13:14:29:

I was thinking of the 2 sun -2 planet type that can be done with just spur gears like this and this

Edited By JasonB on 30/10/2018 13:24:08

Thanks for the links Jason, I think the first one is the way to go, very neat and space saving too.

Ron

[Ron LadenParticipant @ronladen17547]

Thinking more about motor/gearing what is a sensible top speed for small scale engines 6-7mph..?

Also the top end(ish) crank rpm of a steam driven engine..?, with motor drive its just to try and keep a balance of something realistic.

Ron

[Paul KempParticipant @paulkemp46892]

Ron,

I would say 4mph would be plenty fast enough for something your size, maybe 5 if you want it turbocharged! As to crank revs, it's a little subjective. It's been said a Showman's engine when generating does around 150rpm. A full size Avelling roller from a royalty sheet working back the crank revs from quoted road speed is around 300rpm flat out. So no more than 300rpm at top road speed for you I would say – you can't scale time! Less wouldn't hurt. Most general purpose engines were two speed, high and low gear. "Road" locomotives – those designed for haulage were three speed.

Paul.

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