Steam-Wagon Steering Query (Ackermann)

[Nigel Graham 2Participant @nigelgraham2]

Mulling over how to design the steering to replace the temporary and rather weak worm and wheel presently on it.

Measuring shows a lift at the steering-column of 1 inch lock-to-lock.

I can either use a worm and wheel of heftier form, or make a screw-and-nut gear; and have a candidate 2-start worm for the latter, from I-recall-not-what, of 0.45" lead.

Alternatively I can cut a 2-start 1/8" pitch (1/4" ) screw and nut. (he says optimistically.

What I need know though, is typical number of steering-wheel turns from lock to lock (That worm would give about 2; a 1/4" lead 4, full turns.)

With no real drawings available, just photos, the steering wheel itself seems about 15" diameter, with a vertical peg handle. I've tried holding a tape-measure to gain some idea of what it ought be, taking into account an early lorry probably did have quite large steering-wheels and possibly a large steering-box ratio as it had no power assistance.

SO……

Could anyone with any sort of miniature steam (or indeed early i.c.) wagon especially with Ackermann steering, or experience with the full size, give me some guide numbers here, please?

[Nigel Graham 2Participant @nigelgraham2]

[Nick WheelerParticipant @nickwheeler]

What makes you think Ackerman geometry affects the number of turns lock to lock? That's entirely down to the gearing in the rack/box/chains/whatever.

[Werner SchleidtParticipant @wernerschleidt45161]

Hi Nigel,

to your question full size cars have lock to lock sterring wheel turns of 3 turns this give a steering ratio measured in straight ahead positon of 15 to 16 to one. This kind of gears are normally assisted by hydraulic or by new cars by electric drive. 25 years ago manual steering was usual at smaller cars there you have 4 to 5 turns lock to lock and in center a ratio of 20 to 22 to one. The steering ratio depends on the length of track lever in full size cars in the range of 125 to 170 mm and the ratio of the gear.

In my Merryweather fire king model i have a trapezoid gear and this give me 10 turns lock to lock . This give in rough calculation a ratio of 120 to one. In the middle position it is more direct. Overal it is light to turn at all driving surfaces . The track lever length is about 70 mm. The fire king is good to control in center position with less lash in the gear and the intermediate shaft i need.

If you want to make a correct ackerman setup it is good to lock in a book for that . But as a rough idea the track levers of the front axle have to point in center position to the middle of the rear axle. This give you different toe ins by steering in a curve. The inner curve wheel have to have more toe in as the outer curve wheel.

I hope this helps.

Werner

[Nigel Graham 2Participant @nigelgraham2]

Thankyou.

Nick –

Sorry, but you've not read me correctly at all.

I did not "think" anything of the sort.

I designed the geometry from a book giving the Ackermann principles, and made the axle and steering a long time ago. All I need now are values to guide making the steering-wheel and gear-box.

Werner –

Ah, very helpful!

So that 4 turns given by a 1/4" (6.2mm) lead screw and nut would be about right; and even 0.2" (5.1mm) lead not too far out at giving 5 turns. (I even have a 5TPI tap.)

Making a nut to fit the 2-start worm I have would be something a challenge, but more seriously using that would make for heavier steering and more tendency for the road-wheels to force the steering-wheel round.

I've not calculated the lever ratios but started by was measuring as well as I could, a very old photograph looking straight onto the front of one of the wagons. That gave me a fair estimation of the proportions of the parts around the king-pin.

A side view photo also gives the rough layout of the steering-box, hence appropriate drop-arm length as its lower end is visible below the chassis rail. It is not clear though, what is inside the steering gearbox. The centres on the arm I have made are at about 90mm.

.

I have looked at selecting an appropriate worm and wheel made for a model traction-engine but examining the appropriate suppliers' web-sites suggest, surprisingly, that none of them sell these now! Stock worms and wheels are readily available, though; and simpler to use than making a screw and sliding nut.

The archive photographs show a triangular steering-box in side view, suggesting either a screw and nut or a worm and quadrant, though with careful design an entire worm-wheel could be accommodated without being obvious.

[Werner SchleidtParticipant @wernerschleidt45161]

Nigel,

in which scale do you build?. My steam friend build a 2 inch Clayton after the original plans , with the difference he made it new with metric conversion. With the original track levers the steering force was to heavy for him on asphalt during driving. So he asked for help but would not to change so much. So I advised him to look if he can change something on the track levers or the connection to the steering gear. He changed the attachment to the gear, because the thread in the gear was long enough and so he attached the gear to a longer lever combined to the track lever so the force is comming down.

That is very difficult to chose if you make the setup for the first time.

Werner

[Nick WheelerParticipant @nickwheeler]

Posted by Nigel Graham 2 on 17/04/2023 09:28:14:

Nick –

Sorry, but you've not read me correctly at all.

I did not "think" anything of the sort.

I designed the geometry from a book giving the Ackermann principles, and made the axle and steering a long time ago. All I need now are values to guide making the steering-wheel and gear-box.

Then why make such a big deal mentioning it? Effective suspension and steering geometry is complex enough that concentrating on the parts relevant to your current issue is sensible. For instance, ensuring that the King Pin Inclination intersects the ground in the centre of the tyre contact patch does have a noticeable affect on how much steering effort is required at the wheel. Getting it right also makes the vehicle actually turn better, instead of scrubbing across the ground.

I know someone who found and installed a stock width rack for his custom front suspension(mostly XJ6 in a Minor). But it was a rear steer rack in a front application and the wheels turned the wrong way. That led to an 18month sulk before he fixed it….

[Nigel Graham 2Participant @nigelgraham2]

Nick –

The relevance of the various lever ratios is simply that of the steering force needed.

I might have give the steering a small castor angle, but studying the photographs closely suggests the original was all-square: no camber, no castor, vertical king-pins but some toe-in. The design had some good ideas but was rather crude even by 1908 standards.

The springs are separated from their seatings on the king-pin brackets by spacer pads, so it would be simple to give the spacers a small castor angle.

It may be possible but more difficult to give some camber.

Toe-in is easy as I gave the track-rod opposite-handed threads for its clevises.

Any king-pin inclination would need completely new assemblies.

However, let's not get hung-up on this. The model represents a rather basic steam-wagon built in 1908, basic even for its time, of probably little more than jogging pace flat-out; not a "modern" car of even 1918 vintage!

'

Werner –

An interesting example!

My wagon is to 4-inch scale, so a hefty beast. The problem with a miniature lorry is that the driver has to sit on it to be able to reach the controls, adding to the weight on everything including the steering.

My mass is a little over half the maximum for my wagon by one-third scale, for a 3-tonne full-size capacity.

I don't know the Clayton's original carrying load, but I think it was about 5 tonnes (well, tons but there is little difference). In two-inch scale the scale maximum load becomes about 23kgs (50lbs).

So an average adult on a 1/6 scale model of a 5T lorry would give the poor thing several times that load!

Even a 10T original would still have a scale maximum of only 46kgs.

If your friend has to sit on his Clayton wagon to drive it (I have seen that done, on a grass sports field to make it even more difficult for the vehicle) it is hardly surprising the steering was so hard! Fine if driven from a trailer that removes all the driver's mass from the vehicle; but not easy or elegant to arrange.

[Martin Johnson 1Participant @martinjohnson1]

Nigel,

It would help to know what you building.

I designed and built Ackerman steering for my 7" scale lorry using "Elements of motor vehicle design, second edition by Donkin. As pointed out, you will probably need quite low gearing as you will be way over scale weight on the axle. That being so, forget about self centering steering. You will need more than 3 turns lock to lock. Full size HGVs back then would have 4 to 5 turns.

I dont agree with some of the comments about setting the Ackerman arm angles, track rod length etc either.

Pm me if you would like a part scan of Donkin. It might even be on t'internet.

Martin

[Werner SchleidtParticipant @wernerschleidt45161]

Martin,

i fully agree with you .

On a passenger car you need some kind of direct steering to have a feeling for the driving dynamic of the car. The car have for that special settings of toe in ,caster and camber. But all of this is in combination with pneumatic tires, if you have solid rubber as usual at traction engines that all is different and sometimes it is good that the steering gear can block ,with a bad backward efficiency heavy loads by driving through holes or anything similar. With my fire king it is good that forces of small couple stones or like that are blocked and sometimes if you fire by driving it is good that the steering is not self centering. Otherwise you have to correct permanent if you drive in very wide curve.

The direct steering in a car is only important for driving dynamics and a handfeeling that you know where you drive and for high speeds.

In a model this is not important.

Werner

[Nigel Graham 2Participant @nigelgraham2]

Martin,

It is a 4-inch scale Hindley 'Light Delivery Van' ( a small lorry rated at 2 or 3 tons load).

I designed the steering links from the photographs and from various reference-books more relevant to Edwardian HGVs than modern cars.

These include J.M. Meyrick-Jones, A.M.I.Mech.I., Steam Road Vehicles, reprinted in 1978 by the National Traction Engine Club; who seem not to have noticed that their title page gives the author's initials as L.M.!

It was written originally in the commercial era of these vehicles, as a guide to their principles, operation and servicing.

This book compares the worm-and-wheel with screw-and-nut gear, remarking that some makers used complete worm-wheels so when one sector becomes worn it can be rotated to a new sector. While the difficulty with screw-gear is of no adjustment for wear, most pronounced in mid-travel. However, we are not making full-size vehicles used (and often abused in their day) heavily 6 days a week, on roads of highly-variable quality!

.

I also used Maurice Kelly's The Overtype Steam Road Waggon, these together giving a wide view of steam road vehicle design principles; while some ancient general-engineering text-books from a second-hand book shop provide an overall summary of early 20C mechanical-engineering practice – including steam-engine designing.*

Among other things these two op.cit. also explain how the traction-engine type rear-axle works, so I could make mine based on modifying a BMC front-wheel drive car differential for chain-drive on the axle, rather than on one wheel.

@@@@@

Werner –

I agree. Looking at the photos and descriptions of the original wagons, I don't think Hindley's drawing-office was too worried about steering dynamics and hand-feeling, either!

In one photo the steering column seems tilted towards the side of the vehicle, as well as backwards as normal. Other advertising material shows the poor driver sitting with both legs to one side of the steering gear-box and column. Oh, and the regulator was an ordinary globe-valve on a pipe leading from the boiler top to the engine; located to the driver's side; and the starting-valve handle (I think it is) was slightly behind his left shoulder.

Photos of the Hindley 5-Ton "Standard" Wagon, with an undertype engine geared directly to the axle, hint that its driver even had to dismount from the cab-less footplate to change road-gear, by a lever visible under the chassis, near the rear wheel.

 

Despite all this rather inconsiderate designing, the maker's own advertisements reckoned "any man of ordinary intelligence" could soon learn to drive it; and a contemporary Commercial Motor magazine reviewer was very impressed by its handling, on a test-drive that consisted mainly of running round London's Finsbury Circus several times. (Hindley & Sons had a show-room in London.)

.

I took the liberty of replacing the clevises I used to represent the prototype's Hooke's Joints in the drag-link, with commercial-item ball-joints. I think ball-joints were used on Edwardian cars, but not on the Hindley lorries. This halves the number of pivots and gives much more positive action.

.

A full-size replica exists (built to commission in the 1990s I think). I have heard that it is an awkward thing to drive, even with ordinary intelligence and far from Finsbury Circus' modern traffic.

,

 

*The oldest book, published in 1911 if I recall aright, has a chapter on water-turbine types and theory, for driving many types of machinery, not only alternators. It ends confidently asserting that the world's rivers should be sufficient for mankind's power needs…..

Edited By Nigel Graham 2 on 18/04/2023 15:04:37

[Howard LewisParticipant @howardlewis46836]

General comments

Dor a 4" scale lorry to carry a 5 ton payloed would equate to 1.66667 tons at scale, so a driver weighing 16 stone imposes an actual load of 2 cwt or 100 Kg. This should be well within the load carrying capacity

With regard to the steering, ideally the centre of the wheel trad should be above the king pin. This will be provided by a dished wheel giving an offset from the mounting face on the hub to the centre of the kingpin.

Presumably the top, since it will be inclined, laterally to accomodate the camber of the road, and longitudinally to provide castor for self centering.

HTH

Howard

[noel shelleyParticipant @noelshelley55608]

Castor, camber, king pin inclination and track. The basics of a steering system. If the weight on the front/steering wheels is thought to be rather high then consider fitting thrust bearings, ball or roller. ARC may be able to help. Others have described the basics of Ackerman steering and the track in turn it gives. Good luck. Noel.

[Nigel Graham 2Participant @nigelgraham2]

Howard, Noel,

It was the 'Standard' wagon that was of 5T capacity, Mine is the smaller "Light Delivery Van' (as the catalogues had it), of 2-3 T load.

So at worst, 2 tons scales to [40/27] = 1.48cwt; approx. 11.9 stone.

So it should carry my roughly 9 – 10 stone – probably not very evenly distributed. Distributed on the lorry platform that is, not on me. Oh, all right….. and on me. Though this assumes I can find somehow / somewhere to have the springs heat-treated.

Whether it will have the power, is another matter….. At best I can't expect more than 1/4HP from the engine, if it manages 400 rpm; a compound fed un-superheated steam at 90psi boiler-pressure, through a loop of pipe exposed to the fresh air. (That's how the original was designed!)

.

The steering-geometry is all there and done… years ago, too. I copied from archive photos that do show the original E.S. Hindley & Sons' draughtsmen were not too worried about such niceties as king-pin inclination etc., and made it all-square. The most I can do without radical re-working is giving it a little castor-angle by wedge-shaped spacers between the axle-beam and the springs. Hindleys' own advertising stated range but not speed, but I'd be surprised if these things managed even a heady 8mph on their smooth steel tyres with remarkably crude brakes, so true steering geometry was probably not all that critical.

.

My original question was anyway about the control end: the appropriate number of steering-wheel turns for a vehicle of this type; to guide designing the steering-box.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Nigel Graham 2 on 22/04/2023 22:23:07:My original question was anyway about the control end: the appropriate number of steering-wheel turns for a vehicle of this type; to guide designing the steering-box.

Unlikely to be critical.

On the original, the ratio is a compromise between the strength of the driver and how quickly the wheels need to steer. To turn a heavy vehicle with no power steering a child would need all the mechanical advantage he could get: large diameter steering wheel plus several rotations lock to lock through a worm or step down gear box.

Not difficult to provide a ratio suited to a weedy child, but it introduces a new problem: the steering takes forever to respond, dangerous at full-speed on bends! Not too scary when 10mph is flat-out, but deadly at 30mph.

In practice, a steam wagon driver would be a reasonably fit grown man, strong enough to manage without so much step-down help from the steering as the child. Still needed a favourable ratio, because a full-day's work on a heavy lorry without power steering was exhausting. Especially if the steering had to be used a lot for close manoeuvring with the vehicle stopped,

On a model with a human driver, much more power is available at the steering wheel because the model is being driven by a scale giant, who isn't tired out by heaving at it all day to earn a crust. Nigel mentions his engine being about ¼HP (about 200W), and a unfit retired human can deliver about half that consistently (100W), and perhaps 1000W in short bursts. When the driver is more powerful than the vehicle, the ratio is less important.

The ratio and power of the steering motor are much more critical in a remote controlled model, where the steering motor is smaller than the main motor. Copying an existing design is easiest, otherwise measure the torque needed to turn the wheels and do the maths! The torque needed depends on the surfaces in contact: a steel rim on tarmac easier to steer than a rubber wheel on tarmac, and both are much easier than the same wheels in deep snow. Very little torque needed to turn the wheels on wet ice, but then the vehicle doesn't steer at all…

Fortunately, model makers rarely have to cover the complicated cases. If it works on dry grass and tarmac that's good enough!

Anyway, I think there's a fair amount of leeway in the answer to this question. Werner's post is most helpful, because he's done it!

Dave

[Nigel Graham 2Participant @nigelgraham2]

I think the only way to measure the steering torque on a model like mine, would be to steer it via a spring-balance!

The full-size steering-wheel had a vertical auxiliary handle, as on a traction-engine and often clipped on to modern HGV equivalents. This does suggest a good deal of "mangling" was needed to manoeuvre the wagon in tight spots such as factory yards.

'

Miniature road steam (and indeed i.c. or electrically-powered) vehicles have it hard because the ground they run on is always at twelve-inch scale; be it a well-mown sports field, a farm meadow or smooth asphalt. I have seen a two-inch scale under-type steam-lorry charging around a sports field with its well-built driver perched improbably side-saddle on it, and wondered at the model's ability at all even on mown grass, on wheels less than three inches diameter.

The full-size Hindley wagons must have been a nightmare in bad conditions such as on wet or icy setts; where their steel-tyred wheels with no strakes or tread of any sort would have given no lateral grip – probably, sometimes little driving grip. The boiler was to the maker's own patent to enable it to operate, so the patent document and the advertising said, on hills up to 1-in-8; and the road serving their own factory was itself very steep. So getting one of these, especially the larger ones, fully-laden up a steep hill in Winter was no joke.

No mention of driving the thing safely down-hill though, either. For their brakes were ridiculously crude even by Edwardian HGV standards too: just one curved iron or steel block, a bit like that on a railway wagon, on each rear wheel, pulled against the rearward "side" by a screw worked from a large crank-handle between the crew seats. It was little better than a parking-brake.

There was no brake on the flywheel, exposed but below the chassis and of no auxiliary PTO purpose.

…..

My estimate of my model's power was from the usual [nPLAN/33000] Horsepower sum, but it makes a lot of assumptions even with a generous Diagram Factor (the 'n' in the formula) – I think I used about 0.7 for that.

I can manage 100W? That's comforting – probably a bit more as I am in fair fettle for 70!

I'll try to remember that when I'm next hauling myself very slowly from the depths of the cave "digging" project I help on – trying to find the cave we hope to find below a mass of boulders. Two hundred feet deep and still going down…. It's a long way back out, a series of short but strenuous climbs then a final 35ft vertical ladder ascent to the sunshine. It would be interesting to know what power I am expending on this, even if taking the "Work Done" as simply lifting vertically my GVW including nearly a stone of damp clothing and kit, ignoring a great deal of friction, very heavy breathing and other "mechanical losses", but I don't really know how to calculate it!

[duncan webster 1Participant @duncanwebster1]

Unless I'm missing a complication it's mass (kg) *9.81*height climbed(metres) /time (seconds), answer in Watts. If you want it in HP then mass(lbm) * height(ft) /time (minutes) /33000.

[Nigel Graham 2Participant @nigelgraham2]

Thankyou Duncan!

At best I can climb 1 ladder rung (9" spacing) a second.

So assuming about 10 stone for me + clothes and kit, this gives about 144W or 0.2HP… So maybe I'm a bit fitter than I feel! I'm still in fairly good fettle, though I am only 70.

In reality it's probably a bit under that, but it still seems right hard work.

(I converted the units to metric then divided the W by 746).

…..

An entertaining digression but getting back to the OP –

We've established my steam-wagon, like its original, has very crude steering geometry; but my question was on steering-wheel size and full lock-to-lock turns.

The photos and experimenting with a tape-measure suggests a wheel of about 15" diameter full-size, so 5" diameter on the model. The present one is only 4" dia. And it is fitted with a small, peg-type crank-handle.

While number of turns, comes to about 5 on the present worm-wheel radius and DP in the gear-box.

Of the two options, a worm and wheel seems the better than screw and nut. A lot less work and the wheel can be rotated on its mounting when it wears, as if I am ever likely to wear it out. Not cheap, as I'd have to buy the two parts, but saving me a lot of time, gaining a better result and still be right for the era, whichever option the original Hindley wagons actually had in there.

I'd likely use a coarser DP for strength and longevity, and slightly larger worm-wheel, so reducing the number of turns. With care not to go too far and make the steering too heavy.

[Martin Johnson 1Participant @martinjohnson1]

Nigel,

Just seen the photo of a Hindley on your pump thread. Wirh the track rod ahead of the king pins, the track rod centres will need to be wider than the king pin centres, which will need a lot of overhang on the stub axles or a well dished wheel (not evident in photo).

All do able, but not a modern layout o Ackerman, so you wont find much info about it.

Pm me if you need more info.

Martin

Edited By Martin Johnson 1 on 26/06/2023 12:59:10

[Nigel Graham 2Participant @nigelgraham2]

Thank you but if you look back through this you will find it was pretty well covered! I had wanted some guidance on steering ratios.

 

Hindleys did not trouble too much about niceties on a steam-wagon not likely to have reached even 8mph on whatever asphalted road it was lucky to find, and I copied a set of photos giving better views than that Dorset Year Book 1977 illustration in the query about pumps.

I also referred to reprints of contemporary manuals for operating and servicing steam road vehicles, not modern motorway cruisers.

I have given the track-rod put a fair amount of toe-adjustment, presently toeing inwards to the front. The whole thing did look all-square with long king-pins and no obvious camber or castor angles. The most I can do now is taper the axle-to-spring spacer blocks, to give the steering a modest castor.

I made the channel beam axle by welding two lengths of folded 2mm thick channel back-to-back and dressing the welds smooth, so it holds insufficient steel to accommodate tapers itself.

.

Despite the apparently poor steering layout, Commercial Motor reviewers of the time (1908) considered it an easily-manoeuverable vehicle to drive, in their road test that involved driving one several times round Finsbury Circus, from E.S. Hindley & Sons' London show-room. Perhaps it was, compared to some of the lumps the magazine was probably offered for review.

Hindley built quite a number of the mid-engined "Light", and the bigger undertype "Standard" and its heavy-duty "Colonial" equivalent, steam-wagons. Hauliers and house-rermovers Pickfords owned a fair-sized fleet of the "Standards" before abruptly moving to another maker, Foden I think.

The Hindley wagon catalogue also reckoned it so simple that any ordinary man can learn to drive it in a short time – so I think I'm in with a chance!

Edited By Nigel Graham 2 on 26/06/2023 14:23:25

Edited By Nigel Graham 2 on 26/06/2023 14:24:27

[Howard LewisParticipant @howardlewis46836]

If it is of any help,

Sentinel steam waggons used a screw and nut steering, IIR, and they were remowned for their dished wheels to place the centre of thtyre aboved the king pin.

It must have worked well considering the high speeds (Especially the later pneumatic tyred ones ) of which they were capable.

The final S types were quite compatible with, and in terms of speed, superior to their contemporary IC powered competitors..

Bulmers used a S6 throughout and after WW2 to deliver cider. Almost silent!

Howard

[Nigel Graham 2Participant @nigelgraham2]

Well, it is interesting but doesn't help my original query because I am constrained by what someone in a drawing-office in the village of Bourton decided 112 years ago; but that feature of Sentinel steam-lorries is used as an example in one of my reference books.

The steering-gear on my model at present is a worm and wheel but is temporary, as it a bit small and weak for the application. I don't know what the originals used because the works are encased, but the shape of the gear-box and what suggests a shaft end on its face, would be appropriate for either worm and quadrant (not full wheel) or screw and nut.

The lack of drawings enforced a lot of lateral research for this project, and this revealed some manufacturers used Ackermann steering fitted screw-and-nut gear, others used a worm and quadrant, some fitted a full worm-wheel that can be rotated to a new quadrant when it wears.

.

My first car was a Sharps Commercials 'Bond Minicar', whose single front wheel suspension – plus engine – was on a near-vertical column rotated by worm and quadrant as on some early road-rollers.

[Andy PughParticipant @andypugh44463]

I have started calling it "Darwin" steering, on the basis that it wasn't invented by Ackerman.

[duncan webster 1Participant @duncanwebster1]

Posted by Nigel Graham 2 on 28/

……

My first car was a Sharps Commercials 'Bond Minicar', whose single front wheel suspension – plus engine – was on a near-vertical column rotated by worm and quadrant as on some early road-rollers.

I knew the chap who holds the Lands End to John o Groats record for one of those. He reckoned he stopped in Preston for a few hours kip, during which time they changed the engine, as driving it flat out continuously hadn't done it any good.

[Nigel Graham 2Participant @nigelgraham2]

I reckon he deserved the kip – driving a Bond Minicar for some 300-400 miles and that only as far as Preston (well under half-way), probably hadn't done him any good either!

One peculiarity of the steering was that the wheel was in a vertical plane, not tilted back slightly, and at a shallow angle in azimuth with the car's axis. So having a right arm slightly longer than the left would have been an advantage.

A more subtle peculiarity was that even if the driving unit column was inclined to give some trail, as a "castor" it was all the wrong way round, with the swing-arm holding the machinery and wheel projecting ahead of the column

The engine he'd worn out would have been either of 200cc or the heady later-optional 250cc. It was a Villiers 2-stroke, air-cooled motorcycle engine with the flywheel replaced by the very heavy, overhung 'Siba Dynastart' rotor; and the column-gear change lever linked to the original cycle gearbox pedal. An extra ignition switch position gave the reverse "gear" by starting the engine backwards. I forget if it used a single contact-breaker set to TDC or a pair of contacts slightly in advance for each direction.

.

Going back to the Hindley "Light Delivery Van", the rather unscientific design of its Ackermann Steering probably did not matter much at all. Hindley's advertising and contemporary Commercial Motor magazine reviews do not mention speed, but it was unlikely to have been more than a few miles per hour.

Probably just as well, on all-steel wheels with completely smooth rims. It must have been a nightmare for the driver to handle on slippery setts on the sort of gradients its boiler was designed to work on, whilst also trying to cope with rain or snow on a cab-less vehicle in Winter. .

However, Hindleys offered wooden artillery-pattern wheels as an option, and were even granted a patent for a steam-wagon wheel given some vibration-absorbing by a thick wooden inner rim between the discs and tyre. I have modelled the latter, scaled from the Patent Application, although no surviving photographs show them fitted; and am contemplating giving the rims solid rubber tyres.

A Bond Minicar? Eeeh, luxury!

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