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I've seen a few cars described on the net using direct drive motors. Does anyone know if they're readily available or are they made by the modellers?

I strikes me they'd be ideal for powering kits with full interiors and original floorpans-not to race mind, just to have a bit of fun and get some oddballs moving around the track without destroying the original too much (I have a yet-to-be-built '59 Cadillac convertible in mind).

I've tried a front-mounted HO motor with propshaft on an Airfix Sprite with full interior and original floor pan and it goes okay (still needs more work though) but I reckon the same setup in the Caddy would be like fitting a BMC A series in real life.

I also like the idea of near-silent running.
 

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Graham Windle
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Direct drive has been done in slots but its never been too sucsees full , what you end up with is a car with poor acceleration and no brakes I tried some experiments last year to see if it was a feasable idea in 1/32 as I know It has a following in ho but even the use of hand wound armatures with better torque characteristics were no beter than a good side winder set up . the other down side was I either had to sleeve the wheels to fit the motor shaft or I had to replace the armature shaft with one of 3/32
diameter.
 

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Discussion Starter · #3 ·
Aha, thanks Graham, I thought it'd be too good to be true.
 

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Grah
QUOTE the other down side was I either had to sleeve the wheels to fit the motor shaft or I had to replace the armature shaft with one of 3/32
Grah, which method did you use for the chassis shown in your pics?
Ages ago (a couple of years!) I saw a post suggesting that stainless steel tubing for mass production of hypodermics needles was ideal for shimming the motor shaft, rather than inserting into the wheel first, but have lost my link to the source.
Do you have a source for suitable sleeving?
This is one of those areas that I have been really wanting to enter for donkey's years and this could be the year if I can find a way to do it easily.

I fully accept that this configuration can't compete well with orthodox 3 or 4 to 1 gearing but it has a strong appeal all of its own - I just have to do it some day!
 

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I've seen pictures elsewhere of cars run in this way, using model train motors and other specially sourced low-rev power units. I got as far as viewing various catalogues for the motors, but a long time ago. Forgotten where they are. Hopefully our US friends will be able to point us in the right direction. It appeals to me, too.

Another way of getting a really quiet drive is by using a rubber grommet over the pinion providing friction drive to the rear wheel, sidewinder fashion. It means you can have a straight sidewinder with much narrower track and smaller wheels than usual. Didn't Carrera do this a while back? Anyway, I used it for some little 1/32 cars way back when, and built a 26D powered 1/24 Ferrari 275P for club racing back in the late 60s. I'm sure there was a Model Cars feature... Dick Smith- ring any bells with you? It was great, but hopeless with soft sponge tyres- as soon as they started to wear, the friction drive went AWOL. It needed constant adjustment, and of course, as the tyres got smaller the 'gear ratio' changed.
 

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You could have a contrate gear on the back like a usual inline drive. Then strip the teeth off and coat the flat plate with silicone sealant. Now use the motor pinion with a rubber grommet as Howmet described and you have silent (inboard) running gear that doesn't need to be adjusted as the tyres wear.

Oh, and as an aside note... Howmet, although you are correct in saying that the gear ratio changes, it makes no difference to the overall speed and acceleration of the car because as the tyre wears the car has more acceleration (due to a smaller drive wheel) but the gear ratio is lengthened because the effective contrate (the tyre) is getting smaller.

In a regular inline or sidewinder car, the gear ratio remains constant as the tyre wears and shortens the final drive ratio, giving more acceleration as the tyre wears.

McLaren
 

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McLaren makes a good point about self-cancelling gear ratios.
Unfortunately, losing the grip kind of renders this less than useful!

Unfortunately, friction drive involves too much pressure, and thus power loss, to be reasonably viable.

Hopefully here is a pic of the now quite old and obsolete Carrera capstan drive for those who have never seen it before, or even those who have and want to see it again!

.
 

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Much digging around, later on, produced the following links:

Direct Drive 1/32 Mercedes
Scroll down that page about 4 screenfuls to see the Merceded W196 by Alan Schwarz, who posts as Ecurie Martini.
Ionce had the link for the motor manufacturer too, but that seems to have been lost in several PC migrations.

SF Topic
That one is interesting too.

Edit: I was just thinking it's about time Fergy turned up!
 

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Graham Windle
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Tropi I wrapped a couple of turns of copper tape round the shaft to enlarge the diameter as it was just an experiment , then took a blank armature and replaced the shaft with a 3/32 one and rewound it to give less rpm but more torque.

Edit : after checking the orignal post It would apear I forced some earbud tube on the shaft of that one my memory isnt what it was
 

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Thanks, Tropi- that's the stuff. Where's EM when you need him, eh?
Still wondering if Dick Smith or John Secchi remembers the fad for friction-drive sidewinder 26Ds- or was I the only one?
 

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Brian Ferguson
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QUOTE I was just thinking it's about time Fergy turned up!

So it was you ringing my doorbell and then disappearing!


My main experience in direct-drive has been in HO. The smaller, lighter cars mask the lack of torque and brakes to a certain degree though it is still very noticeable. Nonetheless, they could be made to be very fast on a non-mag, wood track. In fact, the fastest cars on my 48 foot modular track are direct-drive HO.

But I don't think the concept would scale-up to 1/32 very well. I tried one back in the 60's and was unimpressed by the performance, even with a torquey arm in a 16D. Drive was by short pieces of surgical tubing (epoxied as I recall) connecting the motor shaft to axle half-shafts. Smooth as silk (when the couplings stayed together) but the performance was pathetic on a 1/32 car.

I abandoned the concept entirely until Ed Bianchi sent me one of his HORacePro Rattlers for evaluation. Warned that I would need to drive the car very differently, I persevered, developed a new driving style, and fell in love with the thing! Not only is it the fastest car on my track, it is also the most consistent, and I can drive it close to the limit lap after lap. It was, in fact, the key to my success in the ORS series because I could not get a conventional HO car to circulate as quickly or as consistently.

But 1/32? I think gear reduction is mandatory!


Howmet, I did the friction drive thing too, and probably with 26Ds at the time! Smooth as silk, but I never found a way to keep the wear-and-tear on the components from affecting the car even over short periods. Enough tension to stop wear-related slippage problems, and performance went downhill due to friction.

Of course.... both of the above concepts might be feasible if someone with more expertise than me (okay.... that includes anyone!
) can work it out properly!
 

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I found it intriguing that Alan Schwarz himself was quite deprecating of his very nice Mercedes, yet the Electric Dreams people really rated it very well, indicating that availablity of the right tyres would have made it even better.

As I said previously, I honestly don't expect this type of car to compete with top end othodox configurations, in a similar way to not expecting front wheel drive to compete on equal terms either. But this doesn't have to mean there isn't a place for them.

A no-gears class sounds quite attractive to me, the only snag being how to get the wheels onto the motor shaft. Hmmm . . . I bet BWA could help there, him making a tremendous variety of bores already . . . it could be that a 2mm bore wouldn't be a problem, eliminating that problem!
 

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I had the priviledge of driving EM's direct drive car at that Marconi proxy race. As I went down there as one of the drivers for the race for PDL. Great fun being able to drive the many varied cars and designs. The next year I entered some of my own cars.

Em's car was built and looked very nice but had absolutely miniscule brakes into corners and poor acceleration out of a corner. It was very smooth running and handling as long as you braked far enough ahead of time, it went around corners smoothly. But you just lost too much time waiting to slow down or accelerate. Convinced me, not to try any such setup. EM's tires also arrived too late to fit up, as his first choice was delayed from the maker. So he lacked some traction on that track also. Em has confimed this himself.

I can't recall any sucessful 1-1 racing cars either with 1-1 drive, even with big torgue monster engines.

Larry Ls
 

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I would go with the friction drive - the secret here is silicone tires! Don't know if you saw but I ran a little King F/D Mecom Lola at both Turin and Bordeaux vintage races this year and the thing was a champ! Just uses a regular Russkit 22, and it had excellent acceleration, brakes and handling. Smooth running too - until I forgot to oil it before the final, when it did a good impression of a mouse in the last two segments (no bearings, the axles run in aluminum holes! The King cars use a simple spring tensioner, which seems to work very well.

Don't know about England, but these never seem to have made much of a hit in the USA.... They tried, but it never caught on.... King had the only commercial car of this type, and AJ's also came out with their "Demon drive", which were just silicone "pinions".

The only brief trend I remember hearing about was Ray Gardner, ex Champion man, who said friction drive was the way to go on his home track ca 1966, with silicones and rewound 36Ds... don't imagine that fad lasted too long either.

Direct drives were easier then too, because the big Pittman and Ram type motors had 3/32 or 1/8 shafts.... I think this was tried a few times in drag meets (usually on 24, 30 or 36 volts), and I do remember one article saying somebody had finally dared the direct drive approach and his car worked well - don't think it won though!
Don
 

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Jim Moyes
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A few years back I won a big lot of slot cars on Ebay in the States. I was mainly after the Monogram MGA in the lot of about 13 "cars" in various states. A couple of them have homebuilt chassis with sidewinder mounted 16Ds with a toothed pinion rubbing directly on a rear tyre. The motors are mounted in slotted brackets and a coil spring is used to tension the motor against a fixed point on the chassis, supposedly to account for tyre wear!

Mr.M
 
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