Aerodynamics
olimarler - 17/5/17 at 08:31 AM
Hi All,
In the process of planning the improvements in the aerodynamics of my 7.
Got my front winglets ready to go on.
Also will be looking at front splitter, Ali underfloor and then rear diffuser.
I've seen a few &s with the rear spoilers.
Question is how are people mounting these to the rear role cage?
Cheers
Oli
loggyboy - 17/5/17 at 09:32 AM
Improve it in what way?
Do you want less drag or more grip? or both?
benchmark51 - 17/5/17 at 09:44 AM
One of the best things I did to my locost 7 was the rear diffuser. I made a flat 1.2mm plate to fit between the rear of the tub to rear of the floor.
Cut a 6inch hole beneath the diff. This was bonded and riveted to the chassis. Then made 4 fins from ally and bonded and riveted them to the plate.
The difference was quite a surprise, so much quicker. The 'parachute' effect was gone!
olimarler - 17/5/17 at 10:15 AM
Bit of everything really.
Looking at the underneath of the car is a giant parachute!!
Just had thoughts about the rear spoiler too
loggyboy - 17/5/17 at 10:23 AM
quote:
Originally posted by olimarler
Bit of everything really.
Looking at the underneath of the car is a giant parachute!!
Just had thoughts about the rear spoiler too
Without going for a rebody, (and moving away from a 7-esque car) the underbody is the only real way to reduce drag. Although a half torneau cover and
aeroscreen (if you have a full screen) will also help a lot.
Unless you are experiencing less grip at the rear at high speeds, a spoiler will just add drag. (and IMO look ubergay).
sam919 - 17/5/17 at 11:26 AM
One thing you'll find with a full undertray is the lack of air escaping from the now enclosed engine bay, so engine temps will increase if you
dont provide a suitable escape path. You'll find your feet will get hot, hence the duct on the bonnet on the drivers side at the pedal box
location on some C400 caterham race cars
Anything below 70-80mph in a 7, aero, doesn't really have any valuable effect. Unless your racing, these mods are more for the look rather than
anything else.
The rear aerofoil, will indeed not have any great effect apart from a good place to rest a cup of tea in the garage, it will in most cases slow you
down. MSA regs, if relevant, dont allow attaching anything onto the cage like this. They have to be done directly to the spaceframe.
If you really want aero, and are prepared to go a bit mental have a look at RSP seven's, and the oroginal black brick! Oh, and at the end a
picture of the nurburgring caterham that was banned for being too quick....not a wiff of aero in site....
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olimarler - 17/5/17 at 01:54 PM
quote:
Originally posted by sam919
One thing you'll find with a full undertray is the lack of air escaping from the now enclosed engine bay, so engine temps will increase if you
dont provide a suitable escape path. You'll find your feet will get hot, hence the duct on the bonnet on the drivers side at the pedal box
location on some C400 caterham race cars
Anything below 70-80mph in a 7, aero, doesn't really have any valuable effect. Unless your racing, these mods are more for the look rather than
anything else.
The rear aerofoil, will indeed not have any great effect apart from a good place to rest a cup of tea in the garage, it will in most cases slow you
down. MSA regs, if relevant, dont allow attaching anything onto the cage like this. They have to be done directly to the spaceframe.
If you really want aero, and are prepared to go a bit mental have a look at RSP seven's, and the oroginal black brick! Oh, and at the end a
picture of the nurburgring caterham that was banned for being too quick....not a wiff of aero in site....
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Great images!!
I have the bonnet scoop and also flared side panels. I was thinking about directing the air out of the rear clam by having some holes along it. No
Gearbox in the tunnel as a BEC.
Also the rear diffuser wasn't going to be tight on the rear clam too too alow air out.
All still in planning stage so happy for ideas
Cheers
sam919 - 17/5/17 at 02:20 PM
Another angle on it here!
If we think about a lot of the formula cars where the engineering is real world, the cooling is done with radiators mounted on the side. If a radiator
was mounted in this area to offer sufficient cooling, you could then remove the need for it up front which would also move the weight towards he
centre. A lot of work for not a lot of gain but worthy of thought.
I noticed you've a full cage, without being hampered by MSA regs, the area between the parallel bars could be filled in, being rectangular it
could be wing shaped , curved to allow flow over it and also downforce/ drag, haha.
Those squared off front cycle wings also introduce better air flow, these can be cut off 70mm above the centre wheel hubs or more, this will reduce
the drag experienced on the trailing edge as air gets trapped in this area. Same with the rear arches and as you've suggested holes in the rear
basket.
Good project, you should find it interesting! and if you take the 7 to the extreme, you end up with a slippery club racer!
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[Edited on 17/5/17 by sam919]
02GF74 - 1/6/17 at 07:10 PM
whilst this looks good, is it schoolboy playing with photoshop or as a result of wind tunnel testing, I suspect the former.
Other than a series land rover, the lotus 7 shape is probably the worse aeorodynamic shape ever 
good luck with it.
sam919 - 1/6/17 at 07:38 PM
You seem to be historically up on the black brick caterham?
sam919 - 1/6/17 at 07:48 PM
No real access to wind tunnels in the 70's for your typical club racer. Good article on the pioneering spirit here, where would we be without
trying things out?!
http://tentenths.com/forum/showthread.php?t=129950
Mr Whippy - 2/6/17 at 11:40 AM
quote:
Originally posted by 02GF74
Other than a series land rover, the lotus 7 shape is probably the worse aerodynamics shape ever good luck with it.
Depends on your point of view - aerodynamically the landrover is perfect as it prevents you going too fast and crashing due to the fantastically bad
handling and dodgy brakes…
