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Smoothing the airflow on a 7 !!!!!

The Village Idiot

By The Village Idiot
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The Village Idiot

The Village Idiot

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I know it's quite funny seeing as they are brick shaped.

 

Now the question I have if you did everything easily/commercially possible to smooth/control the airflow does it make any actual difference to high speed grip?

 

I am thinking rear difuser, smoothing the bottom of the car even further with carbon sheeting, the new whiskers and aero wishbones plus a little nosecone lip?

 

Has anyone actually quantified how much the 7 wants to take off at speed and whether the above makes any difference?

 

Final question I have about the aero wishbones, I believe that they are just oval shaped instead of reverse aerofoil shape too push the front down. If they are just oval shaped surely this make the front want to lift more than just the standard round front wishbones?

 

Dicks

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taffyracer

taffyracer

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Interesting question as this is something we're in the process of doing, from experience of other cars I have developed I know that open sections under the engine bay, central tunnel and rear sections create masses of turbulent air underneath which really harms top speed and grip in fast corners........aero whiskers, engine undertrays and diffusers will certainly help if done properly but beware....I have bought various parts from online sellers both in the UK and abroad in the last few months, not 1 part has been useable and the quality of parts like this that I have seen are very very poor, most are so flimsy that they are borderline useless, which is why we're now developing our own, i don't have measurements but as I said I know if done properly it will help and we will be testing these parts back to back vs standard to record lap times/speed

 

C7 YUM

 

Edited by - taffyracer on 30 Aug 2010 15:02:28

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CageyH

CageyH

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One thing to consider in smoothing the airflow, is still being able to cool the engine sufficiently.

 

One problem area is the cockpit.

A good way to decrease the drag will be to put the roof on. *wink*

I am sure that will help!

 

Only dead fish go with the flow....!

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Gavin H

Gavin H

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One thing to consider in smoothing the airflow, is still being able to cool the engine sufficiently.

 

I had a theory that if you flat floored the whole car, with a diffuser on the back, and suitable hole in the difuser (at a low pressure point, maybe between fins) then it woudl suck air through, thus reducing the temperature in the engine bay. Not sure if it would still create issues for the diff temperature.

 

If you had 'fins' set up across the diffuser, I figured you could achieve good airflow across/through the engine bay and still get a useful increase in downforce on the back (i.e. 3 'channels' and only one with a hole to draw out hot air).

 

Of course it could all be a load of old cobblers, and I may not get the chance to try as home refurbishment has led to an imminent sale of the R300 ☹️

 

I'd be interested if anyone though my idea had any merit...

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myothercarsa2cv

myothercarsa2cv

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Will upload this tonight, and post a link later. Though it's not that long... It'll fit here I reckon:

From Curborough Site

I was lucky enough to have my car selected for the test session. Following various conversations with Graham Kendall, who not only manages the Wind Tunnels at MIRA, but also competes with daughter Claire (yes that Claire) in the rapid Metro, I prepared a few add on devices in readiness for the limited time available for the structured tests in the Wind Tunnel, whilst some other lucky club members had a tour around the facility. Apart from the obvious Caterham design I had added a full flat floor under tray and rear diffuser. Previous theories on airflow meant that I already raced with the front number plate mounted low down on the front of the nose cone. Yes I know you are all asking, "Why on earth would you want to do wind tunnel tests on something as un aerodynamic as a Caterham 7?" Well even though it has the aerodynamics of a brick, there are still very useful things that can be accomplished using a test facility such as the Full Scale Wind Tunnel at MIRA. Armed with a multitude of cardboard cut outs and tank tape I was aiming to reduce lift on the front axle to balance the car and hopefully improve the drag at the same time. The first series of tests consisted of a splitter below the number plate, an additional spoiler below and blending. I won't bore you all with the full technical results but in summary these changes actually reduced aerodynamic drag and lift at the front. The action of reducing front lift actually increased rear lift by pitching the car around its centre of gravity. The next areas of attention were the front cycle wings. The theory was that air flowed both above and below the wing surface acting exactly like the wing of a plane. This caused a depression on the top surface relative to the air below causing lift. Blanking off the gap between the wheel and the wing did indeed reduce lift and drag, but without increasing rear lift. These results were further enhanced with the addition of a low sharp edge towards the back of the wing in an attempt to trip the air up and not follow the contour causing depression.

At this stage CD (drag) had been reduced by 3% and front lift decreased by a whopping 14kg. How could I not resist looking at the front suspension? Now obviously I couldn't remove it all so I made covers for all the exposed round section tubes to change them to pear drop section. Although improvements were made, they were nowhere near as big as the effort in making the new sections! Another few kilos of rear lift were lost by adding wheel deflectors to the lower edge of the rear wings in front of the rear tyres, but at the expense of a little drag. Then came the addition of side skirts to the car. I set these to give ground clearance at all times under racing conditions. These had an overall reduction in lift of 9 kg but a slight drag increase. As I stated earlier I had already fitted a very pretty carbon fibre rear diffuser. However the shape of this was wrong based on textbook theory. The MIRA experts decided it was not long enough and the diffuser angle was nowhere near the optimum range. Copious additions of very stiff cardboard went some way to correcting this situation. But no matter what we tried, the best solution was to consign it to a very large skip! (The diffuser, not the car!) From a suggestion by one of the group present, we also added additional blending profiles to the windscreen posts. Although not strictly legal in my racing class, it did improve drag very slightly. Lastly for amusement I removed all of the weather equipment (roof and doors). This increased the drag force through the proverbial roof requiring a further 10bhp at 100 miles/hour, but actually created some more rear down force. I would like to thank Graham Kendall, Ivan Starkey & Paul Atkin for making this very interesting visit happen and for the opportunity to complete these tests, which sadly I have not had chance to convert into road/race-worthy modifications."

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