Drag coefficients

[Bob Culver]

Rather than continue the topic under gear changes,  I found some old notes from Autocar 30.7.65 which possibly warrant a separate entry. Included drag coefficients for sample cars, including what seemed to be an RN/RP.
Some may remember the other models.

Vauxhall VX4/90 (Victor 101) .526, Ford upright Popular 1948-1960s .493, VW Beetle 1200 .48, Mini .46, Ford Consul Mk 1 .455, BMC 1100 .453, A55 .441, Rover 90 .41, Standard 10 .403, Jowett javelin .387, Porsche 356 coupe .333, Citroen DS .326. 
Austin Seven .608. 
Max power of older cars is usually reached before top speed. However the 47 bhp Consul about 75mph, the 68 bhp Zephyr 81 mph, the 50 bhp Javelin 80.   Three box saloons are generally inferior to station wagons/vans. Other sources for the same cars differed somewhat.
Unstreamlined Citroen Light 15 56 bhp 73 mph. The unstreamlined post war MG saloon but with front mudguards closed and sloping screen 70 mph on 45 bhp.
It is the cross section area times the co efficient which matters

[Steve Bryant]

So...... if I fit a chin spoiler or a rear wing I'll lower the drag coefficient  on my '29 AD van ? 

 
Stephen

[merlinart]

Rather than continue the topic under gear changes,  I found some old notes from Autocar 30.7.65 which possibly warrant a separate entry. Included drag coefficients for sample cars, including what seemed to be an RN/RP.
Some may remember the other models.

Vauxhall VX4/90 (Victor 101) .526, Ford upright Popular 1948-1960s .493, VW Beetle 1200 .48, Mini .46, Ford Consul Mk 1 .455, BMC 1100 .453, A55 .441, Rover 90 .41, Standard 10 .403, Jowett javelin .387, Porsche 356 coupe .333, Citroen DS .326. 
Austin Seven .608. 
Max power of older cars is usually reached before top speed. However the 47 bhp Consul about 75mph, the 68 bhp Zephyr 81 mph, the 50 bhp Javelin 80.   Three box saloons are generally inferior to station wagons/vans. Other sources for the same cars differed somewhat.
Unstreamlined Citroen Light 15 56 bhp 73 mph. The unstreamlined post war MG saloon but with front mudguards closed and sloping screen 70 mph on 45 bhp.
It is the cross section area times the co efficient which matters

It would be interesting to read that article.

Arthur

[Malcolm Parker]

It is interesting that in July 1934 The Light Car magazine tested a 1934 RP Saloon back to back with the 2 seat tourer.  The lighter tourer was slightly quicker off the mark but the saloon recorded a higher maximum speed which suggests that the boxy saloon may be more aerodynamic than an open tourer.

[Mike Costigan]

... and the Kamm tail on a van beats the saloon!

Back in the day Tony Griffith's chummy had a better power to weight ratio than my van (not least because I always got all the camping gear!), but on a long motorway run I could leave him for dead!

[AustinWood]

Maybe that's back to gear ratios again!