9 replies to this topic

[Jobjoris]

Anyone an idea why the Porsche 936 of Jacky Ickx and Gijs van Lennep finished the 1976 24hrs of Le Mans with a covered/taped NACA duct in front of the windscreen, while they started with an open one? I was triggered when I saw Spark's 1/43 of the 1976 Le Mans Winner.

 

They started like this:

But finished like this:

Thanks!

[Doug Nye]

Rain?

 

DCN

[Jobjoris]

Rain?

 

DCN

Nope, the 1976 edition was warm and dry. Only liquids noted on the car was that champagne!

[d j fox]

Indeed it was , my abiding memory of that race was the sun beating down and the heat.... so maybe the duct was for driver "cooling"?--perhaps then too much cooling? or maybe wind buffeting their helmets or their hands on the steering wheel?

[Michael Ferner]

Hot days, cool nights... It's probably as simple as the team forgetting to take the cover off in the morning.

[Jobjoris]

Indeed it was , my abiding memory of that race was the sun beating down and the heat.... so maybe the duct was for driver "cooling"?--perhaps then too much cooling? or maybe wind buffeting their helmets or their hands on the steering wheel?

It could be something like that. The 1977 (winning) 936 had no NACA duct anymore so it definitely wasn't that needed. 

[Dipster]

Bugs getting in?

[2F-001]

936 began that year with a similar duct - positioned slightly further forward - but the whole cockpit surround, airbox (and rear fins and wing) were different then too. The lead car ran at Imola in May with this later cockpit surround and higher wing - but no airbox or small duct ahead of the screen.

 

Paul Frère's book on the '70s race cars goes into minute detail of the aerodynamic developments - but that particular little feature doesn't seem to warrant a mention.

[Tim Murray]

The report in Motoring News mentioned that in the early part of the race the drivers were suffering from overheating in the cockpit, to such an extent that Ickx suffered a blistered foot. Presumably it would have been at this stage that the duct configuration was changed to alter the airflow through the cockpit. Whether this involved opening it up or blanking it off remains to be determined.

[Jobjoris]

The report in Motoring News mentioned that in the early part of the race the drivers were suffering from overheating in the cockpit, to such an extent that Ickx suffered a blistered foot. Presumably it would have been at this stage that the duct configuration was changed to alter the airflow through the cockpit. Whether this involved opening it up or blanking it off remains to be determined.

Sounds reasonable, most plausible explanation yet. Thanks!