RE: Bicycle tech for Caterham
Discussion
hufggfg said:
While I'm all in favour or development and lightening, this seems a bit ridiculous... What does a Caterham bare chassis weigh? 100kgs? 150kgs (My guess is that it's actually less than 100kgs)? So even achieving the target of 10% reduction they've only saved 10-15kgs...
True enough, but in a car that only weighs around 500 -550 kg in the first place, it'll still have a positive effect on power-to-weight ratio and, presumably, acceleration and braking performance.Oz83 said:
I'm sure they have done their homework but the thing with bike frames is that they don't have to take any sideways loads. I wonder how these butted tube sets fare in the event of a side impact crash.
The chassis would be triangulated in more than the one plane that a cycle frame (excluding the stays) exhibits. That ought to deliver the required resistance to lateral stresses / impacts.Hopefully they'll crash test a few for type approval anyway!
Reynolds tubing was previously used for the front-end subframe of the E-type Jaguar. They have 'form' ...
As for Caterham - at face value I'm reticent. You catch a kerb bad on a track day , and it'll be a new chassis front-half section, not merely a wishbone - just because you tweaked the wishbone mount and it went the route of unintended-consequences. See comments above about wall thickness and fixability. There are times when dumb tech (square tube) remains simple and sufficient.
Put another way - if weight loss is not pursued to this more-fragile sort of extent via selective thinwall tech, I doubt Caterham will be pulling 8-10kg out of the chassis tubing without also losing stiffness. As it is, the chassis isn't the heavy bit of the 7; I'd rather Caterham kept the thing the same weight and stiffened it up overall as the benefit.
Any driver can lose a stone meanwhile.
I bought, still run, a very light car. After which I pulled-up nearly 4% on the power:weight ratio by pie/curry-avoidance. Easy, and of greater benefit overall. (It's 508kg now fuelled & with me in it - working on getting to the even 500, by working on me. Car remains just fine..)
As for Caterham - at face value I'm reticent. You catch a kerb bad on a track day , and it'll be a new chassis front-half section, not merely a wishbone - just because you tweaked the wishbone mount and it went the route of unintended-consequences. See comments above about wall thickness and fixability. There are times when dumb tech (square tube) remains simple and sufficient.
Put another way - if weight loss is not pursued to this more-fragile sort of extent via selective thinwall tech, I doubt Caterham will be pulling 8-10kg out of the chassis tubing without also losing stiffness. As it is, the chassis isn't the heavy bit of the 7; I'd rather Caterham kept the thing the same weight and stiffened it up overall as the benefit.
Any driver can lose a stone meanwhile.
I bought, still run, a very light car. After which I pulled-up nearly 4% on the power:weight ratio by pie/curry-avoidance. Easy, and of greater benefit overall. (It's 508kg now fuelled & with me in it - working on getting to the even 500, by working on me. Car remains just fine..)
Edited by Huff on Monday 26th October 21:30
hufggfg said:
While I'm all in favour or development and lightening, this seems a bit ridiculous... What does a Caterham bare chassis weigh? 100kgs? 150kgs (My guess is that it's actually less than 100kgs)? So even achieving the target of 10% reduction they've only saved 10-15kgs...
I very much suspect that this is mostly about PR and marketing. All three firms get free marketing from their industry press for doing very little. The clue being this story published prior to any actual work.
What's really important is that it shows Caterham's PR and Marketing dept are on top form which is essential for a niche firm like this.
hufggfg said:
While I'm all in favour or development and lightening, this seems a bit ridiculous... What does a Caterham bare chassis weigh? 100kgs? 150kgs (My guess is that it's actually less than 100kgs)? So even achieving the target of 10% reduction they've only saved 10-15kgs...
Agreed, that was my first thought. The chassis is nowhere near 100kg. A locost chassis is about 60-70kg, so I'd expect a Caterham to be lighter than that. I think you're looking at 5-7kg saving. 
Ex Boy Racer said:
Very interesting. But it reminds me of the people I see at track days, with highly expensive carbon bits and bobs, light alloys, racing seats etc who could save 10 times as much weight by going a bit easier on the pies...
Or go and have a dump before a race / track session....On later Space Shuttle missions NASA left the main liquid fuel tank unpainted to save weight. I don't think they had to use any bicycle bits....
“After the initial two Shuttle flights, NASA determined 600 pounds could be shaved from the tank’s launch weight by no longer coating the tank in white latex paint. Instead, the orange spray-on foam used to insulate the super cold propellants is left bare.”
http://opencurriculum.org/9378/how-much-does-the-p...
“After the initial two Shuttle flights, NASA determined 600 pounds could be shaved from the tank’s launch weight by no longer coating the tank in white latex paint. Instead, the orange spray-on foam used to insulate the super cold propellants is left bare.”
http://opencurriculum.org/9378/how-much-does-the-p...
Ozzie Osmond said:
On later Space Shuttle missions NASA left the main liquid fuel tank unpainted to save weight. I don't think they had to use any bicycle bits....
“After the initial two Shuttle flights, NASA determined 600 pounds could be shaved from the tank’s launch weight by no longer coating the tank in white latex paint. Instead, the orange spray-on foam used to insulate the super cold propellants is left bare.”
http://opencurriculum.org/9378/how-much-does-the-p...
I think a Caterham is 5kg lighter if unpainted. Once you're in such a lightweight area, you're into incremental gains anyway, be that laying off the pies, removing your windscreen for better aero or having a lighter frame. What's of real interest to me is whether the properties of the chassis will be properly taken into account as a whole platform. There may be additional gains to be made on the chassis side as a result of being able to engineer certain stiffnesses and flexes into the chassis itself.“After the initial two Shuttle flights, NASA determined 600 pounds could be shaved from the tank’s launch weight by no longer coating the tank in white latex paint. Instead, the orange spray-on foam used to insulate the super cold propellants is left bare.”
http://opencurriculum.org/9378/how-much-does-the-p...
Plus, lets not forget that Caterhams are, in the grand scheme of things, not expensive cars (when compared to modern exotica), therefore the proposition of ownership needs to be the same. Having a repairable chassis is a big deal to me, and steel is very repairable. It is something that puts me off using an Elise for a trackday car and a CF chassis would be a worry and no doubt cause a significant jump on my track insurance as any decent shunt will write off the chassis, or at the least leave you requiring an expensive and time consuming strip and rebuild in order to analyse any damage.
battered said:
Cost, basically. The existing 7 chassis has a lot of box tubes. That stuff is dirt cheap and presents nice flat surfaces for welding. Now take round tubes and weld one to another at 90 degrees. Ah, can't just cut them square any more, can you? In addition butted tubes demand that you know the length in advance, because the middle of the tube is too thin to take the braze. That adds cost.
The Caterham chassis (and the Lotus before it) are mostly made from round section tubes anyway. It's the clones that use RHS (e.g. Westfield, Dax, MK, MNR, Locost etc.)Mr2Mike said:
The Caterham chassis (and the Lotus before it) are mostly made from round section tubes anyway. It's the clones that use RHS (e.g. Westfield, Dax, MK, MNR, Locost etc.)
Dunno about that. My 96 Caterham had plenty of square box. All the rails under the tub, for a start, quite a bit in the engine bay, and so on. Maybe 50-50, from memory, and making it from 100% round would have been laborious.Mr2Mike said:
The Caterham chassis (and the Lotus before it) are mostly made from round section tubes anyway. It's the clones that use RHS (e.g. Westfield, Dax, MK, MNR, Locost etc.)
The side rails etc are all square section. 5kgs off of the chassis and a connection with Reynolds is all hunky dory but fitting better wheels would be cheaper and make far more difference. The average Caterham driver is carrying 5kgs too much anyway...
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