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Policar


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Accurate reproduction of the Hewland FG400 gearbox...... With the newer materials on hand I rekon this would be an improved version... .... I think i've seen a set up like this when younger... only with metal stamped gears........... can already see how the home tuner can get more out of this,,,,, dremels ready!!!

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Doesn't one of the fly classic F1 cars have a setup like that?

I can see why you would want that setup, as it's a nice low profile, but does the extra layshaft add much inefficiency?

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With the extra gears it may have a different sound too. I like the look of it, nice to see scale F1 cars with a bit of thought. I would like a nice steering set up too as they look so good sliding though corners with opposite lock on. Can't have it all though.

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The rear end in what appears to be a prototype is very different to the poster. The prototype has ball races and good lateral axle control. The picture on the poster appears to have bushes and appears to use the plastic gear to control lateral axle movement. I would expect reduced performance and lifespan from the poster style rear end.

 

I wonder which setup was used in the facebook video.

Edited by Garry J

Cheers,

Garry J

Slotworx_Logo_Small.jpg

Old age and treachery will overcome youth and skill

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Yeah, Garry, well spotted - we'd have to assume the prototype in the video was running the same setup as the static ones in the pics..

The difference in rolling quality between ball races and bushes is something we'll learn later I guess.

 

One thing that I haven't heard mentioned in all the discussion of the gear system, is the amount of offset in the unit.

The motor shaft is fairly obviously well below the rear axle line.

 

Assuming a rear OD of say 20mm The rear axle centre-line is 10mm above the track.

An ff-050 motor is 12mm high.

So 6mm centre-line of motor shaft, add say 1mm for ground clearance below chassis/motor case. = 7mm

 

That means you have 3mm of offset if the tyre O.D. is 20mm, ( 20 /2 = 10mm - 7mm = 3mm)

 

That is something this gearing system can achieve that probably couldn't be done efficiently just using hypoid crowns.

 

Being engineering-challenged I'll also be interested to learn what effect this sort of gearing system has on braking per se.

Of course if you start with a 25K motor, and pull it down 4 to 1 or more, you make gains as well.

 

One thing we can be sure of, the brains trust behind this won't bring a pup to market.

Recovering Lapsed Slot Addict :ph34r:  *  Custodian of many used screws (mostly loose :rolleyes:)  *  Total kidder  *  Companion of other delusional slot addicts :lol:  

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Here's the fly Version...

Fly+Williams+FW07+03.jpg

Stolen from http://manicslots.blogspot.com.au/2009/12/news-fly-williams-fw07.html

 

The biggest advantage of the Policar one is that the whole assembly is much narrower...

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The police being narrow is not an advantage from an engineering point. The closer the bearings are together any wear will be multiplied at the wheel. This is always a problem with narrow F1 bodies unless the bearings are located as per scale on the uprights like the Beardog chassis.

The Fly gears are no where near the quality of the Slot it product. But can be improved with some proper setting up.But the extra load does still show on the track.

Interesting to see that the Prototype Lotus seems to be running what looks like a Carrera 25,000 motor, when Policar name is owned by a German company!

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didn't consider the Fly as a similar setup seeing it had beveled gearing included.. ,,,, as clever as the Fly's gearing is... I noticed Kev's car had a shuder/vibration @ high revs when not under load, (found loosening the gear/transfer housing remedied this,, but didn't think was ok.) though on track,, the high revs are never reached,, & gear train is under load....

 

as for the help in breaking with the Policar,,, I guess this is due to the extra friction & leverage with the gearing....

 

Noticible friction or not......... at the end of the day,, another design that brings the cars much closer to accuracy(body wise) for the absolute enthusiast... or for others.. a re-run of an older ofering which will run @ today's standard

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Ah I found Andrew Rowland's reply "some place else on the web" with a summary of the thinking behind the design.

 

It pretty much confirms many of the discussions above.

 

Just to give a little bit more detail and explain the thinking behind the gearbox mechanism. This was all explained at the launch but as that was in Italy few details have probably reached ......

 

There are really three reasons for the design:

 

1. Any Grand Prix car from the 1970's needs to use a slimline motor if it is going to get anywhere close to scale dimensions. The problem with slimline motors is that although they can rev hard they have no torque and so no brakes. The gearing mechanism designed provides exceptional braking so that these cars handle just like cars with larger magnet motors.

 

2. One way for slimline motored cars to have brakes is to have small pinions and huge crowns. Of course normal crowns of any size placed on the rear axle are far too big to create a scale looking rear end to the car. The gear mechanism places a tiny gear on the rear axle allowing very close to scale gearboxes.

 

3. With the large diameter tyres needed for this period the centre line of the axle and if a traditional pinion-crown is employed, the motor centreline is equally high. With the gear mechanism the motor can be placed very low in the car, and central in the chassis to provide a perfectly balanced car.

 

Finally it is envisaged that many of the parts developed for these cars will be available as separate kits for scratchbuilders to provide parts to build up resin bodies with very competitive and scale parts which currently are not available.

 

I hope that helps give more information and answer questions. Sadly I don't think they'll be available in a matter of a few weeks.....

 

Cheers

Andi

Recovering Lapsed Slot Addict :ph34r:  *  Custodian of many used screws (mostly loose :rolleyes:)  *  Total kidder  *  Companion of other delusional slot addicts :lol:  

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  • 7 months later...

Agree with Kalbfellp I have a Slot it Ferrari 312b and it does look very much the same car which is still available here and also in kit form , regarded as a good car but dated slot wise in competition since the M8D came along , looking forward to the F1's . :)

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Quality looks there, it looks like a one piece body, no pic's of the chassis

 

The only difference would be the price, it would have to be cheaper .... why would you pay top dollar for a Slot.it clone

Quickly read this post before it is deleted or i turn grey again

Gary

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  • 1 month later...
  • Vinno unpinned this topic

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