RE: Spartan-V: The 300kg Bike-Engined Track Car
Discussion
rhinochopig said:
There is a kit car that uses an aprillia V-twin though. The problem with BECs though is that for track work they really need a dry sump system.
The Aprilia V-twin is dry sumped as standard in its bike installation. The Ducati engine used by the Spartan is wet sump as standard, though, I believe.
BILL PAYER said:
Strictly speaking there is no such thing as an Aprilia engine its the same unit as found in the Suzuki TL 1000 and the SV1000
Nonsense. The Aprilia engine is built by Rotax.This is the Aprilia V-twin:
And this is the Suzuki:
Quite apart from anything else, there's the small matter that the Rotax/Aprilia engine is a 60 degree V-twin, whereas the Suzuki is 90 degree.
I'm designing a road-going single seater around an Aprilia engine at present; my design weight is slightly lower than the Spartan, but then (apart from the fact it only has to accommodate the driver) I'm using a lot of tricks to get down that low (carbon tub instead of steel trellis frame, monoshock suspension front and rear, single rear brake caliper and disc, combined wheel/hub/disc mounting bells to avoid the need for separate hubs and wheel nuts, etc., etc.).
I share Cymtriks and others' views that I'll believe these weight claims when I see the car independently weighed on an accurate set of corner weight scales. It's not impossible for a non-road legal car (300 kilos would be considered very lardy for a bike engined hillclimb single seater, even with a 4-cylinder engine), but the photos and specs show a lot of features that don't particularly demonstrate any attempt at weight saving: the comedy-size wheels, big, comfy Sparco seats and vented disc brakes, for example.
Formula SAE cars are obviously quite light, but you have to remember that they are only 600cc engines and have very short wheelbase (dictated by the Formula), so are more dimensionally compact than any realistically useable track car.
If you want to see what can be done for light weight when you're not bothered about road legality or a passenger seat, have a look at this, though (208kg, despite having a 4 cylinder, 1100cc engine and a full complement of dampers and brake discs).
The Spartan is very pretty, though...
Edited by Sam_68 on Saturday 18th September 11:50
Sam_68 said:
and vented disc brakes, for example.
Mine weigh in at under 3kg per side, a little lighter than theirs as mine have a direct drive bell and run fully floating, whereas theirs bolt to the bell on the lugs and are solid, but not much.Edited by PhillipM on Saturday 18th September 12:30
HBFS said:
Intriguing post Sam, you haven't got a build thread have you?
Nope. I haven't even got a build - it's all still on paper (or at least on CAD) at the moment, with the exception of the Aprilia engine and some of the suspension hardware, which is cluttering up my workshop. 
...which means, of course, that I'm in no position to be criticising people who have actually produced something in the metal (assuming that Spartan aren't just better at producing CGI images than I am; unlike Cymtriks, I'm of the opinion that at least some of the shots are studio photos of a real car, rather than just CGI's, but I could be wrong).
I wouldn't be happy releasing information on some of the tricksier bits (suspension, mainly) yet, anyway.
Sam_68 said:
rhinochopig said:
There is a kit car that uses an aprillia V-twin though. The problem with BECs though is that for track work they really need a dry sump system.
The Aprilia V-twin is dry sumped as standard in its bike installation. The Ducati engine used by the Spartan is wet sump as standard, though, I believe.
BILL PAYER said:
Strictly speaking there is no such thing as an Aprilia engine its the same unit as found in the Suzuki TL 1000 and the SV1000
Nonsense. The Aprilia engine is built by Rotax.This is the Aprilia V-twin:
And this is the Suzuki:
Quite apart from anything else, there's the small matter that the Rotax/Aprilia engine is a 60 degree V-twin, whereas the Suzuki is 90 degree.
I'm designing a road-going single seater around an Aprilia engine at present; my design weight is slightly lower than the Spartan, but then (apart from the fact it only has to accommodate the driver) I'm using a lot of tricks to get down that low (carbon tub instead of steel trellis frame, monoshock suspension front and rear, single rear brake caliper and disc, combined wheel/hub/disc mounting bells to avoid the need for separate hubs and wheel nuts, etc., etc.).
I share Cymtriks and others' views that I'll believe these weight claims when I see the car independently weighed on an accurate set of corner weight scales. It's not impossible for a non-road legal car (300 kilos would be considered very lardy for a bike engined hillclimb single seater, even with a 4-cylinder engine), but the photos and specs show a lot of features that don't particularly demonstrate any attempt at weight saving: the comedy-size wheels, big, comfy Sparco seats and vented disc brakes, for example.
Formula SAE cars are obviously quite light, but you have to remember that they are only 600cc engines and have very short wheelbase (dictated by the Formula), so are more dimensionally compact than any realistically useable track car.
If you want to see what can be done for light weight when you're not bothered about road legality or a passenger seat, have a look at this, though (208kg, despite having a 4 cylinder, 1100cc engine and a full complement of dampers and brake discs).
The Spartan is very pretty, though...
Edited by Sam_68 on Saturday 18th September 11:50
I notice those saying the weight is believable are those who havent tried to build something similar so don't realise just how difficult it is to get something like this below 400kgs, let alone 300kgs. To get it a genuine 300kgs wet and make it safe/robust enough for track use would be nigh on impossible. The thing most don't realise is that the chassis / bodywork on a car like this isn't that heavy anyway, you're looking at perhaps 40kgs for a good spaceframe and 10-20kgs for GRP bodywork depending on design, so although a carbon body sounds impressive, even bodywork made of fresh air isn't going to save you tens and tens of kilos in weight.
A Caterfield is perhaps not as light as it could be because it's not engineered purely for track, but even something like a Radical or Mallock Clubman car with a bike engine, both specifically designed for racing / track use and to be as light as possible, can't get close to 300kgs so I cant see how this is any different.
The whole lot smells of pie in the sky figures to generate media coverage to me, they've obviously designed the car in CAD and are probably basing weights on what the CAD software is telling them, which probably doesnt know about lots of ancilliary stuff like wiring loom, instruments, paint and trim panels etc. As for the 175mph top speed, that's also a joke probably based simply on the gearing available. Something like a Sylva Phoenix looks just as aerodynamically slippery, and even with a 200+bhp Megabusa engine it would struggle to hit 150mph.
A Caterfield is perhaps not as light as it could be because it's not engineered purely for track, but even something like a Radical or Mallock Clubman car with a bike engine, both specifically designed for racing / track use and to be as light as possible, can't get close to 300kgs so I cant see how this is any different.
The whole lot smells of pie in the sky figures to generate media coverage to me, they've obviously designed the car in CAD and are probably basing weights on what the CAD software is telling them, which probably doesnt know about lots of ancilliary stuff like wiring loom, instruments, paint and trim panels etc. As for the 175mph top speed, that's also a joke probably based simply on the gearing available. Something like a Sylva Phoenix looks just as aerodynamically slippery, and even with a 200+bhp Megabusa engine it would struggle to hit 150mph.
Even if we forget about these quoted kerb weight figures. They have come up with a very beautiful car there. Even if in the real world a road legal version weighed 600kgs, they are still really on to something desirable.
If those pictures are computer generated then they are the best I have ever seen. Have another look it does look real.
If those pictures are computer generated then they are the best I have ever seen. Have another look it does look real.
Looks great in those pics. My global gt1 is 390kg/185bhp with the r1 engine. Stick a v-twin in there and it would be in the 400's. That makes the claimed weight of this thing seem a little optimistic. Either way, it should be good. I doubt it will benefit from having those 17inch wheels though, apart from looks wise. A lot of money too. I'd rather have a GT3 daily driver and a radical track toy, for that money!
LocoBlade said:
A Caterfield is perhaps not as light as it could be because it's not engineered purely for track, but even something like a Radical or Mallock Clubman car with a bike engine, both specifically designed for racing / track use and to be as light as possible, can't get close to 300kgs so I cant see how this is any different.
There's an interesting topic on the weight of US D-sports (bike engined sports racers) here. Lightest was 355 kilos with a couple of gallons of petrol. Admittedly that will be with a 4 cylinder engine and some other race stuff (roll bars, rear wing, extinguisher, etc.), but I think it proves what a challenge 300 kilos would be.I've seen sub-350 kilo 750 formula 'Clubmans' type racers and bike engined Sports Libre hillclimbers, too, but never anything close to 300.
I'm convinced that a <300 kilo, non-road legal (and possibly non-race legal, to lose some of the heavy safety equipment) 2-seater is doable, if you are absolutely obsessive about weight reduction, but I'm doubtful it could be achieved with a spaceframe and there would be plenty of other tell-tale signs with things like the wheels and brake spec.
LocoBlade said:
As for the 175mph top speed, that's also a joke probably based simply on the gearing available. Something like a Sylva Phoenix looks just as aerodynamically slippery, and even with a 200+bhp Megabusa engine it would struggle to hit 150mph.
I didn't spot the top speed, being as it was listed in km/h - that certainly is pure fantasy!53 years ago this was launched, ready for the road fully trimmed with heater radio and spare wheel etc it tipped the scales at 635 kgs.
with half a century of newly developed techniques and materials we ought to be able to do a lot better by now , if the will is there?
with half a century of newly developed techniques and materials we ought to be able to do a lot better by now , if the will is there?
Edited by RTH on Sunday 19th September 17:17
Would the safety / performance level of a 50+ year old car be acceptable now though? Both add weight because both require additional strength.
No doubt that technology has improved immeasurably since those days, but the car in question here has a basic spaceframe which is the same concept using the same materials as the Lotus 7 which was also launched in 1957 IIRC, so it's hardly cutting edge. If you gave a clean sheet of paper to an F1 design office and said build us a 300kg 2 seater Im sure they could do it, but it would require bespoke (ie expensive) parts throughout the car and some clever packaging to make it happen, its not something you're going to achieve simply by slapping a carbon body on a spaceframe and buying generic lightweight parts from a motorsport catalogue to make it roll.
No doubt that technology has improved immeasurably since those days, but the car in question here has a basic spaceframe which is the same concept using the same materials as the Lotus 7 which was also launched in 1957 IIRC, so it's hardly cutting edge. If you gave a clean sheet of paper to an F1 design office and said build us a 300kg 2 seater Im sure they could do it, but it would require bespoke (ie expensive) parts throughout the car and some clever packaging to make it happen, its not something you're going to achieve simply by slapping a carbon body on a spaceframe and buying generic lightweight parts from a motorsport catalogue to make it roll.
RTH said:
53 years ago this was launched, ready for the road fully trimmed with heater radio and spare wheel etc it tipped the scales at 635 kgs.
with half a century of newly developed techniques and materials we ought to be able to do a lot better by now , if the will is there?
with half a century of newly developed techniques and materials we ought to be able to do a lot better by now , if the will is there?
Edited by LocoBlade on Sunday 19th September 18:20
LocoBlade said:
Would the safety / performance level of a 50+ year old car be acceptable now though? Both add weight because both require additional strength.
No doubt that technology has improved immeasurably since those days, but the car in question here has a basic spaceframe which is the same concept using the same materials as the Lotus 7 which was also launched in 1957 IIRC, so it's hardly cutting edge. If you gave a clean sheet of paper to an F1 design office and said build us a 300kg 2 seater Im sure they could do it, but it would require bespoke (ie expensive) parts throughout the car and some clever packaging to make it happen, its not something you're going to achieve simply by slapping a carbon body on a spaceframe and buying generic lightweight parts from a motorsport catalogue to make it roll.
The 1957 Lotus Elite did not have anything in common with the Lotus 7 .No doubt that technology has improved immeasurably since those days, but the car in question here has a basic spaceframe which is the same concept using the same materials as the Lotus 7 which was also launched in 1957 IIRC, so it's hardly cutting edge. If you gave a clean sheet of paper to an F1 design office and said build us a 300kg 2 seater Im sure they could do it, but it would require bespoke (ie expensive) parts throughout the car and some clever packaging to make it happen, its not something you're going to achieve simply by slapping a carbon body on a spaceframe and buying generic lightweight parts from a motorsport catalogue to make it roll.
RTH said:
53 years ago this was launched, ready for the road fully trimmed with heater radio and spare wheel etc it tipped the scales at 635 kgs.
with half a century of newly developed techniques and materials we ought to be able to do a lot better by now , if the will is there?
with half a century of newly developed techniques and materials we ought to be able to do a lot better by now , if the will is there?
Edited by LocoBlade on Sunday 19th September 18:20
It did not have a steel spaceframe. It was an all GRP monocoque structure comprising of 3 major GRP mouldings all bonded together with bonded in aluminium pick up points for the drive train and suspension to form a light and stiff structure it was manufactured by the Bristol aircraft corporation to very high standards of accuracy and strength fitted with an all aluminium Coventry Climax engine and aluminium gearbox either from ZF or MG It had box structures which also gave it very good energy absorbing properties in impacts for the time.Drivers got out from massive high speed crashes at Le Mans.
300kgs for a small road going sportscar is unrealistic, but I see no reason why one could not be made today at 700kgs which by definition would give good performance/roadholding and handling, low emissions and low fuel consumption and included all requirements. Even todays Lotus Elise has reached 900kgs.
The kerb weight of cars today is staggering, the newly launched Mini Countryman weighs 1400 kgs .... and they regard that as a Mini car.This is more than 700kgs more than the original Mini.
One of the first bike engined lightweight cars back in the late 90's was the Strathcarron SC5A and which used the Triumph 1200 motor, a composite chassis designed by Reynard Racing Cars with all up weight of approximately 650kg. One of the biggest development refinement issues was theTriumph drivetrain and gear shift via a Quaife LSD incorporating reverse gear. I do wonder how well some of these bike transmissions will take the loads imposed by two sticky fat tyres. The sound of that Triumph at 10k flat chat and with clutchless gear shifts will remain a happy memory! Anyone know where I could find an SC5A?
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