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· Al Schwartz
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3,416 Posts
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The premier class in our local race series this year is a GT40 - Cobra Daytona (none running - not competitiive) Fly classic series ( 908s etc) - the latter allowed a second, forward placed magnet. The latter cars have been the consistent winners on the tighter courses but today's race was at Jim Butt's 75' Scalextric Classic track. I suspected ( correctly, as it turned out) that the superior speed of the GT40s would give them an edge so last night I decided to tune up my GT40 which had seemed a bit off the mark (no top end) on its last outing.

As soon as I opened it up, I could see a problem - the drive assembly was very sloppy with poor gear mesh and a lot of play in the bearings. On closer inspection I found that it was not an issue of wear or misalignment but rather a question of total collapse! There was a crack under the motor mount ( end bell end) and cracks extending from the bottom of both bearing mounts. Neither low viscosity CYA nor plastic welding cement would repair the cracks well enough to restore the original fit. I put the whole assembly aside "for another day"

I see three problems here:

1. If you examine a Fly sidewinder motor/axle carrier you will see molded in reinforcing edges all around the snap-in motor and bearing mounts. No such feature appears on the Scalextric parts.

2 & 3. For reasons that are not clear Scalex chose, erroneously, I believe, to revert to the old idea of a "top and bottom" body with the bottom of the body incorporating the chassis. (This may, a first glance be attributed to the need to model the marked undercurvature or "tumble home" of the GT40 body but is clearly unneccessary, viz. the Fly GT40 and the Carrera D type) There are several consequences of this decision:

The bottom part must be molded of a material that will reproduce detail and take paint well, not necessarily one which will have the best engineering properties.

The chassis cannot be replaced short of obtaining a whole lower section (and, in the case of my car which I bought in white and painted, a complete redecoration) - I have not seen these lower components advertised for sale.

I know, the problem could most likely have been averted had I glued the motor and bearings into the car. I do not like to do this for two reasons:

I have found that the motors in magnet cars that are run hard have a finite life and I like to be able to swap in a new motor quickly

It is my practice to "prep" several rear axle assemblies (wheels, tires, axles and gear) with different trued tire fitments to suit different tracks on our circuit - again, difficult to implement with a glued-in axle.

The best current arrangement, in my opinion, is the motor/axle sub-assembly used by Fly. When they wear or crack, they are simple and cheap to replace.

Scalextric did a nice job on the body contours (better, I think, than the Fly), gets good marks for detail and finish but could very well be held up as the 2003 example of how not to engineer a slot car.

EM
 
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