A Tale of Tails

The graph above is posted around the net & has been attributed to Dr Robert White.  Who published it is also a question but it might be Porsche guru Bruce Anderson's Porsche 911 Performance Handbook, or it could be Frères, or even Pano - hey, it's the Internet where 3/4 of the info is stolen or borrowed.  But I would give credit if I knew.   It shows the effect of different tails on the 911.  Nicely proves that tails are not just for looks, but perform an important function - keeping the rear end planted.  Tails do not create down force (a point that is discussed endlessly by the learned types in links below) but reduce lift as the graphs illustrate.  The Carrera Tail & the original 3.0 litre N/A & Turbo Tails have very similar characteristics so I thing it's fair to assume a very similar curve for both - labeled Turbo above.  The 3.3 Turbo Tail provides the greatest lift reduction but, of course, at the expense of added weight in the rear.  Many feel the 3.3 Tail  only looks good on a wide bodied car - the author tends to agree.  If I used a picture of your car below with no photo credit, too bad.  You posted it somewhere & I stole it.

Oh, rumour has it that Porsche discovered the effects of a tail by accident.  Someone left an engine lid up during a wind tunnel test & hmmm . . . 
For the history see Trick of the Tail

Note:  Always use a chin spoiler with ANY rear spoiler.  Failure to do so can result in increased instability at illegal speeds.

Duck Tail
As seen on a '72 RS

Early Tails

'74 Carrera 3.0 RS
Hard & rubber edges were market/application dependent

75-77 Carrera & Early Turbo Tails
 Fiberglass with single grill & rubber lip - no AC

'75 Early Turbo Tail with smaller rear grill for oil cooler

'76-'77 Early Turbo Tail with larger rear grill for AC

Alternate Tail ~'76 thru early SC
All polyurethane with large single grill

1980 Weissach Tail
Fiberglass with single grill & rubber lip

 

3.2 Carrera Tail 84-89
The classic Whale Tail
Also available in late '82-'83 for ROW cars

 

 

3.3 Turbo Tail 78-89
 The classic Tea Tray (also used on standard body SCs 81-83)

 

For a good read on tails see Philip Raby's great article from 911 & Porsche World here.


Most info above stolen from the very knowledgeable Bill Verburg on Pelican Thread Here and Another

 

To further your knowledge on Porsche Aerodynamics

AutoSpeed Article - Aero Testing

For some interesting Pelican Posts on the topic see my Forums Links page under Aerodynamics

 

      


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