Caterham 'bricks' and the effect of aerodynamics
Discussion
It has been often said that the Caterham is like a brick, with its aerodynamics limiting its speed. I race a road converted Caterham and was wondering if I should go to the expense of installing an alloy passenger tonneau, alloy boot lid, lowering the wing stays etc. Would anyone like to hazard a guess how much time this would gain or speed??? cheers
As TT said throw more power at it, that always helps.
However as you mention that you are racing your Caterham, I am sure you are restricted by the regulations for your class, which would apply to both power and body mods, so be careful what you change.
I assume you are running with a cage, but you don't mention if you are using a windscreen?
If you are go to an aero screen, it's one of the biggest aero dynamic improvements you can make, as the screen acts like an air brake.
I know the bigger classes use alloy panels on the passenger side, and the boot area too, but I don't think they would make a very big change to speed and performance on a lower engined car!
Keep us posted on what you end up doing, and if it makes any actual improvements?
However as you mention that you are racing your Caterham, I am sure you are restricted by the regulations for your class, which would apply to both power and body mods, so be careful what you change.
I assume you are running with a cage, but you don't mention if you are using a windscreen?
If you are go to an aero screen, it's one of the biggest aero dynamic improvements you can make, as the screen acts like an air brake.
I know the bigger classes use alloy panels on the passenger side, and the boot area too, but I don't think they would make a very big change to speed and performance on a lower engined car!
Keep us posted on what you end up doing, and if it makes any actual improvements?
A Caterham doesn't have the aero of a brick. It has very little frontal area so Cda isnt all that bad.
As I have pointed out several times, the Elise was designed in a wind tunnel and still doesn't do 200mph (in fact a 7 and an Elise with the same bhp have about the same vmax) so limiting factors are bhp and gearing.
Adding stuff at the back of the car probably won't help. Despite actual drag not being that great, they ARE aerodynamically poor and laminar flow turns turbulent about the top of the nose cone. So only major changes like removing the windscreen help to any meaningful degree.
As I have pointed out several times, the Elise was designed in a wind tunnel and still doesn't do 200mph (in fact a 7 and an Elise with the same bhp have about the same vmax) so limiting factors are bhp and gearing.
Adding stuff at the back of the car probably won't help. Despite actual drag not being that great, they ARE aerodynamically poor and laminar flow turns turbulent about the top of the nose cone. So only major changes like removing the windscreen help to any meaningful degree.
Another area is air going into the nose cone, it needs a good exit otherwise it acts as an air brake, they done it with the CSR by getting it to be blown out of the top of the nose cone its more efficient as the cooling will also be better so killing two birds with one stone. Also hot air wont be blown from the exit of the radiator onto the engine.
A flat floor could help, i put one on mine to make up the difference between the lowered floor(also good for lowering your COG and getting your helmet out of the air flow) so there wasnt any difference in height, you could continue this through to under the tank to take the a-frame - diff etc out of the airflow either hugging the bottom of the chassis or continuing along the line of the existing floor height. If you did follow the chassis up at the alight angle sides could be put on to act as a diffuser.
The CSR style front wings say it all for how air flows across a curved surface, the flat rear side stops the air from forming vortexes behind the surface these create drag, the same could be done to the rear arches rather like the Levante, in fact a good car to look at to get ideas.
The whiskers help to create some downforce at the front and the chin spoiler to prevent air from going underneath the car which is important to create a difference in pressure between the topside of the car and the underneath, the lower the pressure underneath the car compared to the higher above it the car will hug the track better.
Most championships dont allow anything non standard or non factory for the model of caterham i.e an R400 shouldnt have CSR style bits on as it wasnt meant to have then originally, but some, towards the north of England and in Scotland are more lenient.
Food for thought though, i have a mate who done the caterham academy/ roadsport and made freinds with another guy, they timed some laps with and without the screen and it didnt make any difference, both quick drivers! So there's a lot of work you can do to a caterham to improve the aero and get rid of drag, but its costly, time consuming albeit and interesting exercise but unless your on the absolute edge of the cars ability the gains might not be as big as one would expect if any.
All these mods even with carbon weigh more and BHP per tonne is key, altering air flow to increase down force will induce drag, and then your into a whole ball game of what tracks suit what set-up, Knockhill for instance is big on power to adding aero etc isnt the way ahead, similiar to Donnington. Mallory's Gerrards is something like 30% of the track length so more downforce for this part is going to help a lot and with no great long straights top speed isnt an issue. It can get very complicated for not a lot of gain.
On the subject of power, and being quicker the best example out there at the moment is the battles a certain few 7 esqe racers have in the BARC NW championships, all handy drivers, one using a high hp, high torque engine with seq box, the other two using bike engines with lower hp/torque but lighter cars all up the front all getting top lap times but with very different set-ups.
A flat floor could help, i put one on mine to make up the difference between the lowered floor(also good for lowering your COG and getting your helmet out of the air flow) so there wasnt any difference in height, you could continue this through to under the tank to take the a-frame - diff etc out of the airflow either hugging the bottom of the chassis or continuing along the line of the existing floor height. If you did follow the chassis up at the alight angle sides could be put on to act as a diffuser.
The CSR style front wings say it all for how air flows across a curved surface, the flat rear side stops the air from forming vortexes behind the surface these create drag, the same could be done to the rear arches rather like the Levante, in fact a good car to look at to get ideas.
The whiskers help to create some downforce at the front and the chin spoiler to prevent air from going underneath the car which is important to create a difference in pressure between the topside of the car and the underneath, the lower the pressure underneath the car compared to the higher above it the car will hug the track better.
Most championships dont allow anything non standard or non factory for the model of caterham i.e an R400 shouldnt have CSR style bits on as it wasnt meant to have then originally, but some, towards the north of England and in Scotland are more lenient.
Food for thought though, i have a mate who done the caterham academy/ roadsport and made freinds with another guy, they timed some laps with and without the screen and it didnt make any difference, both quick drivers! So there's a lot of work you can do to a caterham to improve the aero and get rid of drag, but its costly, time consuming albeit and interesting exercise but unless your on the absolute edge of the cars ability the gains might not be as big as one would expect if any.
All these mods even with carbon weigh more and BHP per tonne is key, altering air flow to increase down force will induce drag, and then your into a whole ball game of what tracks suit what set-up, Knockhill for instance is big on power to adding aero etc isnt the way ahead, similiar to Donnington. Mallory's Gerrards is something like 30% of the track length so more downforce for this part is going to help a lot and with no great long straights top speed isnt an issue. It can get very complicated for not a lot of gain.
On the subject of power, and being quicker the best example out there at the moment is the battles a certain few 7 esqe racers have in the BARC NW championships, all handy drivers, one using a high hp, high torque engine with seq box, the other two using bike engines with lower hp/torque but lighter cars all up the front all getting top lap times but with very different set-ups.
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