Double helical folding hard-top

Spring will be arriving any day now on the Buchanan estate (starting in the south, of course). It's time to start driving some of the convertibles again.

But convertibles are so unsatisfactory, in any one of three different ways. Soft-tops are all well and good, but they look like prams when the roof is up, and even the best fabric roof is not as soundproof as a hardtop. Removable hard-tops are great, except that it takes ages for one's man to remove or replace the hard-top; it has to be stored somewhere when off the car; and one finds oneself bebuggered if an unexpected shower occurs. Folding hard-tops would seem to be a good choice, but they are always clunky and compromivial, with huge amounts of wasted space to accomodate the stowage of the folded lid.

So.

Maxmoto Inc. (a woolly-owned subsidiary of Buchanan Ungineering) is developing the Double Helical Retractable Hardtop.

A graphic would be very helpful at this point - please feel free to draw one.

Imagine a ribbon of steel, about 3ft wide and 10ft long, given a half-twist. Now imagine laying that on one side of a car, running from the top edge of the windscreen towards the back of the car. The front edge of the ribbon is horizontal (and aligns with the left half of the top edge of the windscreen), the back-most edge is vertical, and aligns with the rear left corner of the car.

Now, imagine that we chop off the back 60% or so of this ribbon. What's remains of the ribbon forms the left half of the roof. Now imagine that this ribbon can be slid backwards, corkscrewing around and following the path taken by the original (un-cut-off) ribbon. When slid backwards, it would lie against the rear quarter-panel of the car. Except it will slide back _inside_ the rear quarter-panel.

Now imagine two such ribbons, of opposite handedness, on opposite sides of the car. When slid back, the two ribbons are essentially vertical (with a slight twist in them), and lie between the outer and inner skins of the vehicle in the rear quarter panels. You now have an open-top car.

To close the roof, these two ribbons both slide forward whilst twisting by a quarter turn (the left ribbon turns clockwise, the right ribbon anticlockwise), meeting in the middle to zip the roof shut.

Gadulka!! You have a full retractable hardtop which has only one "seam" (down the centreline of the roof), and which takes up only a modest amount of space between the outer and inner skins of the rear quarters of the car.

Yes, it really did need a picture, didn't it?