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"Lamborghini Countach - gearbox" by Woody - 22/05/2013
55.683 bytes - 263 parts
I'm building the Countach at 1/4 scale,with a fully "working" engine and transmission. Here is the gearbox assembly, which, I was surprised to find, seems to work reasonably well! Both side plates are easily removable for access and a better view. Due to the limitations of the VirtualMec inventory, some parts have been substituted as follows :-
The layshaft is a 6 1/2" tri-flat axle, and the selector socket couplings are also tri-flat (with the added bonus of being shorter so the actual clearance is improved)
The selector forks represented here by couplings and rods, are "selector fork" part 171c, and the longer versions are used to hold the layshaft gears in position. Here, these are represented by standard cranks, the nearest thing I could find to it.
Apart from that, it's pretty much as is.
I've omitted the selector detent rods and springs for clarity. The washers shown are standard, though I used smaller ones in the model. Even so, it's not the best design, they tend to stick a bit, so I may replace the detents with small pulleys.
All the gear ratios shown here are accurate to within 2 percent of the prototype, however, I found that 3rd gear(17t to 19t)didn't quite mesh enough so I replaced these with a pair of 19t pinions for a better result.
The input from the clutch (to be shown later) enters the coupling, and the output shaft (universal coupling) passes back through the sump to the differential.
The transfer gear should be a pair, but here there are three pinions, due to space restriction. This means the direction of rotation is reversed, but this is corrected further back along the prop shaft with another gear pair not present in the prototype.
Next, I'll attempt to show the clutch, engine and differential as seperate items.
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1 Meccano kinematics on 21/06/2013 13:16:36 said

Hello Woody,

Interesting model. Looking forward to some photos of a working model.

With kind regards,

Wilbert Swinkels

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