Lotus 20 / 22 / 20-22

[Neptune]

Several months ago, one of the moderators suggested I ask a question of the Lotus 20 thread, but oh wait, there isn't one. Why don't you start one then, so here it is, started.

I've had a 20-22 for quite a while now. It was a Jim Russell 20, crashed sometime prior to the 1964 season, and rebuilt & upgraded onto a new replacement Arch Motors 22 frame by JRRDS. Like all Russell cars of the period, it went to MGM and became a faux F1 in the movie Grand Prix.

My car in particular became a Yamura. It and three other cars were sold into Florida after the movie debut and raced in SCCA FC class.

Just this autumn, I have acquired the remains of the 2nd Team Rosebud Lotus 20. I never realized how different the 20 & 22 were until I have them side by side.

In the top of the 20 frame, the area right in front of the dash bulkhead, the triangulation tubes are reversed to the 22. Just in front of that, there is a single diagonal brace in that section where the 22 has a "W" brace. Of course the dash bulkhead is only faced on the rear in the 20 and both front/ rear on the 22. The 20 has a battery box right behind the radiator, where the 22 houses an oil tank there.

The main frame longerons are 1in and 1-1/4 in on both cars, but although the 20 carries water through the larger tubes, there is no attempt to carry oil in the smaller ones.

On the 22 frame, there are tabs or plates welded to the bottom of the top longeron tubes and the top of the bottom tubes in the footbox area.These to hold the side panels of the footbox. There is no such arrangement on the 20, yet the 20 looks to have a similar footbox.

Question: How are these side footbox panels held in place on the 20?
Roger