17 replies to this topic

[Manfred Cubenoggin]

I'd be interested to learn which mfg, both road and racing, employed the aero-slippey NACA duct as opposed to merely popping a whacking great scoop out into the air stream? My earliest recollection would be the McLaren M8 of 1968...and even it had 'assists'.

[D-Type]

I've seen references to NACA ducts in connection with the 1956 Costin-designed Vanwall which suggests he may also have used them on his earlier Lotus designs - the Mks VIII, IX & X, and the Eleven.

I don't know enough about land speed record cars, but I suspect they may have featured NACA ducts even earlier.

[David Birchall]

I was interested enough to do a quick search and found this:

The NACA duct, invented in 1945 by NACA (National Advisory
Committee for Aeronautics, which later became NASA - National
Aeronautics and Space Administration) has the interesting property
of *reducing* drag.

I think it would be more correct if it said it causes far less drag than a conventional intake.

I cannot find/recall any instance of a NACA intake on a racing car earlier than the Vanwall as mentioned above.
The correct term apparently is "NACA submerged duct".

[Tim Murray]

In Flying on Four Wheels, his book on Frank Costin and his cars, Dennis Ortenburger states that Costin's use of a NACA duct on the Vanwall was the first time such a device had been used on a racing car. Its use on the Super series Lotus Elite marked the first use on a production road car.

[Pete Stowe]

Originally posted by Tim Murray
In Flying on Four Wheels, his book on Frank Costin and his cars, Dennis Ortenburger states that Costin's use of a NACA duct on the Vanwall was the first time such a device had been used on a racing car.

Not the Connaught F1 streamliner in 1954, then.

[Vitesse2]

Connaught Streamliner in 1954? Shurely shome mishtake?

[Tim Murray]

I would argue that the Connaught had a triangular-shaped air intake, not a proper NACA duct as on the Vanwall.

[HDonaldCapps]

Given the number of folks in Southern California involved in both the aviation and racing communities, it would not surprise me in the least if the NACA duct did not make its appearance on a car from the SoCal area.

[Pete Stowe]

Originally posted by Tim Murray
I would argue that the Connaught had a triangular-shaped air intake, not a proper NACA duct as on the Vanwall.

Tim, looking again at the pictures of Rodney Clarke’s prototype that appeared in Autosport (August 1954, Richard ) they clearly show a NACA duct on top of the nose, not a plain triangular intake.

[Allan Lupton]

Originally posted by Pete Stowe

Tim, looking again at the pictures of Rodney Clarke’s prototype that appeared in Autosport (August 1954, Richard ) they clearly show a NACA duct on top of the nose, not a plain triangular intake.

In his book, "Johnny" Johnson refers to getting help with the radiator intake and the NACA duct from Eric Hall, an aerodynamicist who acted as consultant on aerodynamics generally, and the original (early 1954) drawings of the B type's streamlined body all show the NACA duct.
Vanwall got a NACA duct in 1956 as part of the Frank Costin aerodynamic body.

[Tim Murray]

Having now looked at the 'full frontal' photo of the Connaught which appeared in Autosport in August 1954, I agree absolutely that it features a NACA duct. Many thanks to Pete Stowe for e-mailing me the photo.

So, anything earlier than the 1954 Connaught?

[Tim Murray]

For further photographic evidence that Connaught were using NACA ducts before Costin on the Vanwall, have a look at the photo in this post from Mal9444 in the Dundrod thread.

[Lotus11Register]

Would the air intake at the base of the engine cover of this 1955 Lotus Mk9 qualify as a true NACA duct ?

[bradbury west]

I was intrigued to see at last weekend's FoS that the Talbot-Lago T26 GS from 1951 had a large NACA duct in the spare wheel cover on the off-side wing next to the driver. Surely a recent retro-fitting, or was it in period? Photo available when I sort it out.
Roger Lund

Edited by bradbury west, 09 July 2009 - 14:38.

[arttidesco]

Having now looked at the 'full frontal' photo of the Connaught which appeared in Autosport in August 1954, I agree absolutely that it features a NACA duct. Many thanks to Pete Stowe for e-mailing me the photo.

So, anything earlier than the 1954 Connaught?

Roger mentioned the non period NACA submerged duct on the Tabot Lago T26 GS seen at Goodwood above, while I was looking for info on that car I was surprised to find this November 1953 linked photo, of Louis Rosser aboard another T26 GS taking part in the Carrera Panamericana, which shows a similarly placed submerged duct to that seen on the Goodwood car in 2009.

[arttidesco]

Looking for more info on the T26 GS's it would appear that a NACA submerged duct appeared on the #8 Bayol/Rosier car chassis #11055 at Le Mans in June 1953 which can be seen more clearly on this photo of the same car in July '53 at Reims where Rosier shared 11055 with Yves Giraud-Cabantous.

Which begs the question was the T26 GS seen at Goodwood in 2009 11055 and not 11056 ?

Edited by arttidesco, 03 June 2013 - 21:12.

[Perruqueporte]

This is the bread oven at the side of the inglenook fireplace that we have just uncovered in our 16th century home: https://www.flickr.c...eposted-public/ .  The recess above the open door of the bread oven was designed to use the upward flow of hot air and gases from the open fire below the oven, to draw fumes and and the smell of baking from the oven and up the chimney above.  It is exactly the same principle as a NACA duct, and even has a very similar shape to it.  Extraordinary to think that some bright spark (forgive the pun!) should have observed something in his or her world over 500 years ago, that led to this design.  I shall never look at the front of a GT40 again without smiling at this thought.

 

Christopher W.

[arttidesco]

" The recess above the open door of the bread oven was designed to use the upward flow of hot air and gases from the open fire below the oven, to draw fumes and and the smell of baking from the oven and up the chimney above."

 

As our North American cousins might say one cannot go racing with out bread otherwise known as dough.

 

Doh ! ;-)