(18-08-2023, 10:33 AM)Tony Griffiths Wrote: It would be helpful to have pictures (with rulers) of as many versions as possible; then we have the data saved. I've already put up ones of a Ruby's back seat - here are ones of a front. I can't imagne that there would be any difference between one for an RP and a Ruby - but one never knows.
Tony I'm up with the birdies this morning but will compare measurements to my RP cushions as soon as the sun comes up.
Meanwhile a couple of observations about their construction which may be of interest:
1. The inner and outer tubes are the same size, flattened out they measure a tad over 3.5" across, which by my schoolboy arithmetic implies a basic diameter of 2.25" (obviously this would increase with pressure).
2. They appear to have been made from continuous tube and cut to length; the ends are simply folded back upon themselves to close, presumably with a coating of adhesive. (1st pic)
3. Likewise there are lapped joins in some of the tubes, suggesting that offcuts were simply joined together rather than binned. Again they appear to have been glued, with a fairly generous overlap. This could only have been done on a mandrel of some sort. (2nd pic)
4. Where the tubing has been folded into a "U" shape, the folds also appear to have been glued in place. I guess it's possible the rubber has simply fused together with age, but they seem fairly firmly stuck.
5. The outer tube has a reinforcing/ stiffening band around its periphery on the inside. (3rd pic)
<update> I concur, RP cushion is same as Ruby i.e. (round figures) about 15" x 17".