Scratch that itch; Caterham !

Scratch that itch; Caterham !

Author
Discussion

BryanC

841 posts

202 months

Wednesday 17th February
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agatebox said:
“ I'm fairly sprightly but do all you guys stand on the seat and then slide in ?”
I think we are talking about with a standard hood up.

Passengers get in first, are settled and strapped up.
At 6'2" I consider myself a tall 7 pilot but getting in with hood up, I lead with left leg, then head and body follow before bringing in my right leg and finally twisting and dropping into my seat. The problem is my head virtually drops into my passengers lap which is potentially a 'talking point' especially with the ladies !
Very careful forward planning is needed.
I guess it is easier if you are shorter or more flexible.

PS edited to add a standard S3.

Edited by BryanC on Wednesday 17th February 12:34

bcr5784

5,461 posts

109 months

Thursday 18th February
quotequote all
Surprized no-one seems to acknowledge front end lift. The ducted bonnet and funny cycle wings and strakes on the CSR were designed specifically to reduce front end lift - and were said to halve it at 100mph. You're not going to take off or anything - it just manifests itself as high speed understeer - which you might regard as a good thing!

ian2144

1,606 posts

186 months

Thursday 18th February
quotequote all
bcr5784 said:
Surprized no-one seems to acknowledge front end lift. The ducted bonnet and funny cycle wings and strakes on the CSR were designed specifically to reduce front end lift - and were said to halve it at 100mph. You're not going to take off or anything - it just manifests itself as high speed understeer - which you might regard as a good thing!
I never really had an issue with front end lift, but I didn't use mine on track and it sounds like the OP will be content with road use only..... People do change their mind though !!

Turn7

19,826 posts

185 months

Thursday 18th February
quotequote all
bcr5784 said:
Surprized no-one seems to acknowledge front end lift. The ducted bonnet and funny cycle wings and strakes on the CSR were designed specifically to reduce front end lift - and were said to halve it at 100mph. You're not going to take off or anything - it just manifests itself as high speed understeer - which you might regard as a good thing!
Interesting, didnt know that....

braddo

7,495 posts

152 months

Thursday 18th February
quotequote all
bcr5784 said:
Surprized no-one seems to acknowledge front end lift. The ducted bonnet and funny cycle wings and strakes on the CSR were designed specifically to reduce front end lift - and were said to halve it at 100mph. You're not going to take off or anything - it just manifests itself as high speed understeer - which you might regard as a good thing!
There are not that many places where you're going to be cornering hard at over 100mph though.

No doubting at all that the CSR's mods reduced lift, but the extent of the problem is non-existent for the OP wanting to drive on the road and give it a squirt up the straights.

Put it this way - the 620R doesn't have the CSR's front wings and has the ducted bonnet because of the intercooler.

Amris

153 posts

132 months

Friday 19th February
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For reference, I removed my ducting to aid footwell cooling and haven't noticed any difference on road or track

bcr5784

5,461 posts

109 months

Friday 19th February
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braddo said:
There are not that many places where you're going to be cornering hard at over 100mph though.

No doubting at all that the CSR's mods reduced lift, but the extent of the problem is non-existent for the OP wanting to drive on the road and give it a squirt up the straights.

Put it this way - the 620R doesn't have the CSR's front wings and has the ducted bonnet because of the intercooler.
It has the strakes as well as the ducting. If I was guessing (and I would be) I suspect that the CSR wings weren't fitted to other Caterhams because they are (imo) ugly.


Edited by bcr5784 on Friday 19th February 15:00


Edited by bcr5784 on Friday 19th February 15:34

Darumvej

130 posts

102 months

Friday 19th February
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Louvred wings, like my Freestyle 7, not sure if they make any difference but look good.

bcr5784

5,461 posts

109 months

Friday 19th February
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Darumvej said:


Louvred wings, like my Freestyle 7, not sure if they make any difference but look good.
Not the same as CSR cycle wings.

Glug69

65 posts

86 months

Friday 19th February
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I personally think the CSR wings look better than the standard wings, I would have liked a CSR rather than the Roadsport I had, they look a little bit more modern in my opinion.

braddo

7,495 posts

152 months

Friday 19th February
quotequote all
They are barely noticeable in the context of how different a 7 looks to a normal car.

Glug69

65 posts

86 months

Saturday 20th February
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braddo said:
They are barely noticeable in the context of how different a 7 looks to a normal car.
That is true, no 7 looks like a normal car, but I still prefer the look of a CSR to an S3, and in my opinion when they are parked next to each other the CSR looks more modern, having said that the 620 with the vents in the nose cone is closer to the CSR.

braddo

7,495 posts

152 months

Saturday 20th February
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Yep, they're pretty much just personal preference for a minor styling element of the car.

If front end lift was a major issue, and if the CSR wings made a significant difference to that, Caterham would be fitting these wings to the 620R given that it's faster than any CSR ever was.

It's finally time to be able to use my 7 for a trip to the shops this weekend. driving

bcr5784

5,461 posts

109 months

Saturday 20th February
quotequote all
braddo said:
Yep, they're pretty much just personal preference for a minor styling element of the car.

If front end lift was a major issue, and if the CSR wings made a significant difference to that, Caterham would be fitting these wings to the 620R given that it's faster than any CSR ever was.
Can't see why Caterham would lie about the issue.

This is what wiki says "The CSR, as with all Caterhams, has worse performance at higher speeds with respect to both acceleration and handling because of the poor aerodynamics. Caterhams suffer not only from a high drag coefficient of Cd=0.7, but also from lift.[9] Though there have been improvements in aerodynamics, the CSR still has 50 lb (23 kg) of lift at 100 mph (161 km/h).[1][10] These factors hinder both high-end acceleration, top speed, and handling. With such strong wind resistance, it requires much more power to overcome that force and increase top speed. Lift reduces contact force on the tires, causing the car to feel "loose" and not handle as well.

Even 50lb is a LOT and if it was halved then a Caterham without those mods would have 100lb. That is massive.

rkanaga

396 posts

184 months

Saturday 20th February
quotequote all
braddo said:
Yep, they're pretty much just personal preference for a minor styling element of the car.

If front end lift was a major issue, and if the CSR wings made a significant difference to that, Caterham would be fitting these wings to the 620R given that it's faster than any CSR ever was.

It's finally time to be able to use my 7 for a trip to the shops this weekend. driving
Yup, I did that today as well.

After a long winter I think you can count the cobwebs well and truly blown out!

I need to spend less time on the Collecting Cars website and more in the Caterham.

Turn7

19,826 posts

185 months

Saturday 20th February
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First run out in mine this year today, felt good to actually take some pleasure for a change.....

braddo

7,495 posts

152 months

Saturday 20th February
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It was so good to hear some K induction noise at 7000rpm, albeit for fleeting moments.

Turn7

19,826 posts

185 months

Saturday 20th February
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Agreed, altho my symphony was Sigma provided....

upsidedownmark

1,986 posts

99 months

Monday 22nd February
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bcr5784 said:
Can't see why Caterham would lie about the issue.

This is what wiki says "The CSR, as with all Caterhams, has worse performance at higher speeds with respect to both acceleration and handling because of the poor aerodynamics. Caterhams suffer not only from a high drag coefficient of Cd=0.7, but also from lift.[9] Though there have been improvements in aerodynamics, the CSR still has 50 lb (23 kg) of lift at 100 mph (161 km/h).[1][10] These factors hinder both high-end acceleration, top speed, and handling. With such strong wind resistance, it requires much more power to overcome that force and increase top speed. Lift reduces contact force on the tires, causing the car to feel "loose" and not handle as well.

Even 50lb is a LOT and if it was halved then a Caterham without those mods would have 100lb. That is massive.
Yes, and no..

In engineering terms, yes. If you're pinned through Radillion/other super-fast corner of your choosing, yes (maybe). If you're going to run at go-to-jail speeds on the motorway, also maybe.

Otherwise given it has something like 250kg's (or more) sitting on the front axle, 50kg's of 'lift' (at 100mph) isn't *that* significant if you're doing 80 on the B-somethingorother, and in any case a bit of a lift will transfer a whole heap more than those 50kg's onto the front axle. Nevermind being able to tweak the balance of the car with a 5 minute adjustment of the rear ARB.
Beware too much analysis of abstract numbers in isolation.

Empirically, mine gets tracked a lot. I've never felt that it's got a front end problem. It's not trying to swap ends, nor doing anything scary at the end of a long straight - silverstone gp is about as fast as it ever goes.. and a significant opposite lock moment up the hill to radillion didn't leave me thinking I wanted more front end.

As has already been said, no doubt it generates front lift. Most cars do. Is it a significant concern that should concern an owner - no. Doubly so for a car used primarily on the road (as the OP's question).


Oh, and while I'm on the soapbox, the .7 is CdA, and a caterham has a small A (especially with an aeroscreen). It's not slippery, but it's still a smaller hole than your average tin box smile

Edited by upsidedownmark on Monday 22 February 11:45

bcr5784

5,461 posts

109 months

Monday 22nd February
quotequote all
upsidedownmark said:
Yes, and no..

In engineering terms, yes. If you're pinned through Radillion/other super-fast corner of your choosing, yes (maybe). If you're going to run at go-to-jail speeds on the motorway, also maybe.

Otherwise given it has something like 250kg's (or more) sitting on the front axle, 50kg's of 'lift' (at 100mph) isn't *that* significant if you're doing 80 on the B-somethingorother, and in any case a bit of a lift will transfer a whole heap more than those 50kg's onto the front axle. Nevermind being able to tweak the balance of the car with a 5 minute adjustment of the rear ARB.
Beware too much analysis of abstract numbers in isolation.

Empirically, mine gets tracked a lot. I've never felt that it's got a front end problem. It's not trying to swap ends, nor doing anything scary at the end of a long straight - silverstone gp is about as fast as it ever goes.. and a significant opposite lock moment up the hill to radillion didn't leave me thinking I wanted more front end.

As has already been said, no doubt it generates front lift. Most cars do. Is it a significant concern that should concern an owner - no. Doubly so for a car used primarily on the road (as the OP's question).


Oh, and while I'm on the soapbox, the .7 is CdA, and a caterham has a small A (especially with an aeroscreen). It's not slippery, but it's still a smaller hole than your average tin box smile

Edited by upsidedownmark on Monday 22 February 11:45
Front end lift causes UNDERSTEER so the lift will make the likelyhood of "swapping ends" (far) LESS likely at speed. Stiffening the rear AR bar or softening the front to compensate will give an oversteer balance at lower speeds since roll stiffness affects all speeds equally. Put it another way the front of the car (with driver) weighs around 350lbs (car weight about 700lbs) 100lb of lift will reduce grip by 250/350x100% = 29% at 100mph !!!

Ye canna defy the laws of physics (Jim).

And while you're right that the A in CdA is small it's a long way from compensating for the Cd. My wifes Ibiza does 137mph on 150bhp - you'll need over 200 and an aero screen to do that in a 7.