Aerodynamics and Court Action!

 

 
Extremely rare photo of the Tickford bodywork being tested in the MIRA wind tunnel

 

If you browse on-line forums and Capri web sites, you will come across two very different attitudes
to the bodywork on a Tickford Capri - those that believe it is the most beautiful
 thing on Earth and those who think it is hideous!
 
Love it or loathe it - nobody could argue that the styling is anything less than dramatic
and definitely very 80s.
 

Bottom line............Tickford knew what they were doing!

 
The body panels were the genius of Simon Saunders, a member of
Aston Martin Tickford's Design Team.
 
 He later started his own company called KAT Designs and produced something similar
to the Tickford Capri panels.
 

  Tickford were not happy about this and took court action to stop him.

 
Simon then changed the design slightly to keep Tickford happy.

 

 
Press release from Aston Martin Tickford on the subject
dated September 1983

  

   
On the left - a Tickford Capri On the right - a KAT Capri
   
   
   
Early KAT certainly does look similar, although the front grille Early KAT's rear looks very similar indeed complete with
 isn't blanked and the front spoiler has fog lights with the blanking panel between the lights and number plate
 number plate where the air intake would be being lowered
   
   
   
The later KAT had much deeper spoilers that could be And later KAT rears had the number plate put back
fitted over the original Capri bumpers where Ford intended
   
   
   
Another later Tickford-friendly KAT That clearly shows how deep the spoilers became
   
  Note that the owner of this car has re-added the
  in-fill panel between the rear lights and has
  the standard Capri rubber boot spoiler
  rather than the KAT version
   
   
 
From Fast Lane - March 1985

 

My own opinion is that Tickford were already a bit jumpy about their Capri
as they were on their own with no support from Ford and they
over-reacted to what might have been seen as competition.
 
 The KAT Capris were fitted with a Turbo Technics conversion and upgrades
to their brakes and suspension.
 
 Total cost of a new 2.8i Capri converted this way was about 15,000 which was a
little bit less than the Tickford.
 
Simon Saunders' Capri was actually extremely well put-together and received
excellent reviews in the motoring press.
 
He re-designed his panels and continued to sell the model for a while.
 
20 years on, Simon Saunders is currently manufacturer of the amazing  Ariel Atom  car.

     

Click on the thumbnails to open each page below
 
Pages open in new windows

 

Capri Mild to Wild Magazine - October 1984
 
This article features the early model of KAT Capri that Tickford became so upset about
 
 
 
Fast Lane - September 1985
No Kitten
 
Article featuring Simon Saunders' later Tickford-friendly KAT Capri
 
           

 

The Tickford body panels consisted of six pieces - the blank front grille, front and rear
lower spoilers, pair of side skirts and a huge wing on the tailgate.
 
There was a seventh panel, but this was purely cosmetic, providing an

   in-fill between the rear lights.

 

 
The rear in-fill panel on my car 002 with the number plate on the lower rear spoiler

 

The reasons for the blank grille and slot in the front spoiler have already been
mentioned - to make sure that air is forced where it is needed - through the
 bespoke radiator, Garrett intercooler, oil cooler and air filter.
 
Tickford Capris are notorious for overheating, but this is always down
 to a lack of proper maintenance on the cooling system.
 
A few people have been tempted to replace the front grille with a standard Ford
Capri item to help cooling, but all this does is produce air pressure
differences in the wrong place and suck air away from the
   very components that need it!

       

 
Development of the front bodywork prior to wind tunnel testing - note the extra
cooling vents in the bonnet that never made it to production as they only served
to mess-up the air flow and increase under bonnet temperatures!
 
Plus..........they look as ugly as sin!

 

 
The production front spoiler manufactured by Reliant
 
All the body styling kit was a custom-fit to each car and not just bolted on!

 

A quick physics lesson will help explain the remainder of the Tickford body styling.

 

Firstly, here are two statements of fact............

 

Air pressure differences make a body move (think of wind blowing from high to low)

 

Air presents resistance to objects moving through it (commonly called DRAG)

 

Secondly, there is Bernoulli's Principle which states (in fluids and gasses) that if velocity
 increases, then pressure decreases and vice versa.
 
Try holding two sheets of A4 paper in front of your face, edge on with a gap
of a few inches between them.
 
Gently blow between the two sheets and they will move inwards rather than
outwards - the air is moving in-between the two sheets so pressure
there is less - the greater pressure on the outside of the sheets
forces them inwards.
 
The best example of Bernoulli's Principle is "lift" on an aeroplane wing.
 
The profile of the wing is such that air has to travel further over the top of the wing
than underneath it - the air on top will therefore have to travel faster
and its pressure will drop.
 
The resultant difference in air pressure produces "lift".

 

 
Bernoulli's Principle

 

Finally, there is something called the Coanda Effect - gasses or fluids moving
over a body will tend to follow its surface.
 
Try placing a smooth drinking glass on its side and run it under the tap - the water
does not splash back everywhere, but tries to curve around the glass.

 

 
Coanda Effect illustrated using this Mondeo in a wind tunnel with
a jet of steam being aimed over it

 

Aeroplanes are meant to be in the air, cars are supposed to be on the ground!
 
If you are a car manufacturer, especially one producing high performance vehicles,
it is a good idea to discourage your car from flying!
 

 

 
Add the Coanda Effect to Bernoulli's Principle
and you have an airborne car!
 
 
 
Adding a spoiler at the rear stops the air meeting again
and destroys the lift

 

If you can stop air from getting underneath the car in the first place, then that is even better.
 

  That was the job of the lower spoilers and side skirts on the Tickford Capri.

 

 
Dramatic, very 80s and oh so effective!

 

Studying the above photograph, there is a further panel on the prototype car
that was not included in the production vehicles - a shield
underneath the rear that covers the fuel tank area.
 
 Presumably Tickford decided not to use this part as production costs for the car
 as a whole were spiralling upwards and it certainly would have made
 access for servicing fuel supply components difficult.

 

Tailgate spoilers are sometimes mistakenly referred to as being "wings".
 
 A wing on the back of a car is designed to work like an upside-down aeroplane

  wing and create a downforce to keep the vehicle on the ground.

  

   
This funny car dragster uses spoilers to stop air getting This top fuel dragster doesn't have anywhere to stick
underneath it and to "spoil" the airflow over the top spoilers, so it uses huge wings to create downforce

 

Revisiting the front of the Tickford for a moment, the combination of blank front grille
and lower front spoiler also produced downforce...........so much of it that the
 rear of the car would become light at speed and hence, Simon Saunders

    had to develop an over-size rear tailgate wing to counteract it! 

 
 It is a WING, not a SPOILER!
 

Overall, front end lift was reduced by 40% and rear end lift was reduced to a big fat zero!

 

 
No danger of this taking off at 140mph and leaving the test track !

 

One little word to finish with...............DRAG.

 
Car manufacturers also want their vehicles to slice through the air - increased
performance, improved fuel economy and less wind noise.
 
Tickford managed to achieve a 10% reduction in drag coefficient for their car,

 a drag factor of 0.37 compared to 0.39 for a standard Capri.

 

Bottom line............Tickford and Simon Saunders knew exactly what they were doing!

 

 

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