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March 721X - in need of technical info


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#1 uwe_sautter

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Posted 17 December 2004 - 15:41

Hi all,
need more technical infos / pics from this March 721X.

Here are a pic from the Rainer Schlegelmich archive.
http://schlegelmilch.smcc.de

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#2 Rob Semmeling

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Posted 17 December 2004 - 15:59

I don't think it was necessary to open a new thread but there you go:

http://www.thegaffer...march/march.php

#3 mat1

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Posted 19 December 2004 - 11:17

Nice photo. You can see very well how they tried to make the 721X a "low-polar-inertia" car. The distance between the engine and the rear-axle is unusually high.

As a matter of fact, there were other cars like that, like the Tyrrell of 1972-73. I have always wondered whether that was also such a dog to drive. Apparently not, because JYS became WDC in that car.

mat1

#4 Cirrus

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Posted 19 December 2004 - 13:55

As a matter of fact, there were other cars like that, like the Tyrrell of 1972-73. I have always wondered whether that was also such a dog to drive. Apparently not, because JYS became WDC in that car.



The Tyrrell probably wasn't a dog as such, but it was probably demanding to drive, and required a delicacy that both Stewart and Cevert were fortunate enough to possess. One of Derek Gardener's design objectives for the 007 destined for Scheckter and Depailler in 1974, was to make it a more forgiving car for the two relative rookies. Jody and Patrick certainly seemed to go better in the later car.

#5 Ted Walker

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Posted 19 December 2004 - 14:16

I was looking at the ex Peterson 721X only this morning. It has sat un used since the end of 72 since Ronnie got out of it.Its being re built using the Hewland box , with which ran its last couple of GPs.It may well be out in GP Masters or TGP in 2005.

#6 Roger Clark

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Posted 19 December 2004 - 21:05

There are a lot of designers who have come unstuck building a car with low polar moment of intertia, including Mercedes-Benz in 1936, Ferrari with the 553/555 and Lancia with the original D50. Such cars were usually at their best on slow circuits requiring rapid changes of direction but less good on fast ones where more stability is required. The big change came with the arrival of wings which enabled a car to have the best of both worlds. As speed increses so does downforce, and as this is concentrated at the extremities of the car it counteracted the effect of centralised weight distribution. The Matra MS80 and the Lotus 72 were both successful cars pursuing this goal. The 721X followed the trend, but it was a bad car with a worse gearbox.

#7 Twin Window

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Posted 19 December 2004 - 22:18

I thought this might be of interest or help. Here is the bulk of the March press release concerning the launch of the 721X...

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And I bet not too many others can say they once owned a March 721X airbox, but I can!

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I wrote a bit about how I got hold of it and the other bits here a while back. (That's not my shop, BTW - it's the place that bought them when I was forced to let them go.)

#8 David Beard

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Posted 20 December 2004 - 19:30

Niki Lauda was talking about the 721X a year or two back in Motor Sport magazine. He said (I'm sure I'm not imagining this) that the gearbox was positioned between the engine and the back of the monocoque!!!!!!!

#9 jorism

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Posted 20 December 2004 - 22:47

That's right David, it was a Alfa Romeo gear box, later replaced by the normal Hewland.

#10 Twin Window

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Posted 20 December 2004 - 22:56

Have you read the press release reproduced above?! :confused:

It states that the 721X gearbox will be "mounted in front of the rear axle casing, between the differential and the engine itself"!