jaytee wrote:A nice shot from Custom Car of the chassis plus the car that judging by the roll cage could be an Econorail chassis,wonder how many were sold.
The Econorail was effectively, a scaled down version of the Revolution III chassis design. In production terms, perhaps 2 - or 5 Econorail frames may have been built. Here's the breakdown.
These first three are known to have raced.
1. Ian Fraser's "Econorail" (prototype).
2. Gary Atkinson's "Raindancer".
3. Bob Harman's "Lo-Litre" Puma Weslake - chassis similar, but with structural changes at the rear, (pic Doug McDiarmid).
A press release photo published in National Drag Racer magazine, shows two 'other' frames - the image JayTee has already posted.
4. Dark coloured chassis advertised NDR Nov '73
5. Light coloured chassis advertised NDR Nov '73 fitted with universal subframe bracketry.
The rear of these frames differ from one another, to illustrate the accommodation of a sidewinder? (frame 4) and in-line (frame 5) engine configuration. Also, the roll bar of these two examples differ from that of Revolution III and Ian Fraser's Econorail.
Instead of two roll hoops in close contact like Fraser's car, frames 4 & 5 featured a single transverse roll hoop behind the driver's head, reinforced with two side support tubes linking the top rails and roll hoop. This roll bar arrangement was similar in design to the March 751/761 Formula one car of the same period.
So, did these two 'other' chassis' ever hit the strip or end up as scrap?
There is the possibility that frames 4 & 5 could be frames 2 & 3 with revised roll bars, reverting back to a similar design to that of the prototype.
It can be seen that even on "Lo-Litre", the roll bar arrangement - although similar to that of 4 & 5, appears to have roll bar support tubes of a much smaller diameter and inclined at a steeper angle.
The lower tubes of "Lo Litre" also appear to kick upwards at the rear, whereas the Econorail design ran straight all the length of the chassis. Perhaps therefore the "Lo-Litre" chassis was just influenced by the Econorail design and not an official production chassis??
So, the short answer would be, two certainties, one possible and two don't knows.