I know very little about dragsters, but here’s what came to mind. I would say they use parachutes....
The NHRA requires parachutes over a certain speed. The most important reason they are used is because they provide directional stability while slowing the car. With the lack of suspension, very long wheelbase, narrow track, and extreme rearward weight bias there's no way a top fuel dragster or funny car could safely stop from over 300mph by only braking the wheels, they would lose control. Some fighter jets and the space shuttle use drag chutes for the same reason.
But I do agree that they look totally cool. Plus they provide plenty of square footage for sponsorship advertisement.
Regards,
riff raff
I'd agree with the directional stability reason - afterall, parachutes aren't the most efficient way of actually decelerating the vehicle.
Re: acceleration of f1 car
Posted: 31 Jan 2010, 20:54
by Edis
xpensive wrote:
alelanza wrote:
Ciro Pabón wrote:but I have always wondered why drag cars have to use parachutes instead of regular brakes
I know very little about dragsters, but here’s what came to mind. I would say they use parachutes,
Because they can:....
Valid arguments, but I think our esteemed moderator is also wrestling with the concept of Power being Force times Speed.
- This concept applies to deccelleration as well, why the braking power at that speed would probably cook the hydraulics.
- Also, aerodynamic resistance goes with the square of the speed, why a parachute is four times as efficient at 500 km/h as at 250, while the breaking power disappears into thin air so to speak.
If it cooks the hydraulics there is a design flaw. Friction brakes are intended to heat the brake disc, not the hydraulic actuator.
Regarding the power required to brake a dragster, a 1 ton dragster at 500 km/h is still peanuts compared to say a 180 ton Concorde during an aborted take off.
Re: acceleration of f1 car
Posted: 27 Feb 2010, 17:30
by alelanza
Been watching top fuel for a couple weeks now, and i feel i must restate what i wrote before. I think there's one huge reason why parachutes are used, and no one mentioned it before.
Once these cars get to the 400 m mark, there's no telling what's left of the car. There's a big chance the tyres are destroyed, either due to simply being ripped against the tarmac, or destroyed by a piece of exploding engine head (yes it happens) or what have you. The supercharger belt may have snapped and wrapped itself around an axle. Your engine may be on fire or simply dead so brake assistance may not be there for you.
However an external parachute, which for the most part are relatively safely placed in the back, is your best bet at having a braking chance. I'd say this is THE reason why you want chutes....
timbo wrote:Actually IMO acceleration of an F-1 car (at least at 0-100kph) is not that outstanding. There are quite a few supercars (Begatti, Koenigsegg, Enzo) that are quite close.
But no land vehicle decelerates and turns comparably!
Not really, only the veyron comes close, and that's due to awd. And in 0-60 times, a tenth is a huuuuge difference.
Well, there is the Tesla at 2.5 seconds, but it only costs $120,000 vs $1,900,000 for the Veyron, so maybe it doesn't count.
timbo wrote:Actually IMO acceleration of an F-1 car (at least at 0-100kph) is not that outstanding. There are quite a few supercars (Begatti, Koenigsegg, Enzo) that are quite close.
But no land vehicle decelerates and turns comparably!
Not really, only the veyron comes close, and that's due to awd. And in 0-60 times, a tenth is a huuuuge difference.
Well, there is the Tesla at 2.5 seconds, but it only costs $120,000 vs $1,900,000 for the Veyron, so maybe it doesn't count.
787S, if you continue through the thread, you'll see why a real quick 0-100 time - is not really an F1 forte..
- not least for the actual 0-100 performance - being utilized only once per race.
& re: showroom/road vehicle acceleration value for money.. well, way back in 1999..
US magazine Cycle World, tested the new, sub $10,000 - Suzuki GSX-R 1300 Hayabusa ..
..which duly cut a 0-60 mph (~100 km/h) time of 2.6 sec's - on its way to a sub 10 sec 1/4 mile (~400 m)..
Re: Acceleration of F1 car
Posted: 14 May 2018, 07:07
by gruntguru
And then we have the next generation Tesla Roadster at something like - 1.8 seconds?
timbo wrote:Actually IMO acceleration of an F-1 car (at least at 0-100kph) is not that outstanding. There are quite a few supercars (Begatti, Koenigsegg, Enzo) that are quite close.
But no land vehicle decelerates and turns comparably!
Not really, only the veyron comes close, and that's due to awd. And in 0-60 times, a tenth is a huuuuge difference.
My rwd Ariel atom did (sold a while back) 2.7 from a stock Honda k20a without traction or launch control. It's not hard if you add lightness.
The biggest factor in standing start ET's is the drivetrain being AWD or not. Most high performance cars are traction, not power limited <100km/h. The difference between RWD and AWD is typically around 30-50% of acceleration capacity (depends a lot on the CG height). F1 is always limited by the fact that it's RWD.
The AMZ car is four wheel direct electric drive which is the best case for acceleration. No clutch and gearshifts which are the next next biggest losers of ET in terms of acceleration performance.
Re: Acceleration of F1 car
Posted: 18 May 2018, 19:13
by Tommy Cookers
.... though many say there's is no interruption of or reduction from full torque before, during, and after an F1 gearshift ?
The biggest factor in standing start ET's is the drivetrain being AWD or not. Most high performance cars are traction, not power limited <100km/h. The difference between RWD and AWD is typically around 30-50% of acceleration capacity (depends a lot on the CG height). F1 is always limited by the fact that it's RWD.
The AMZ car is four wheel direct electric drive which is the best case for acceleration. No clutch and gearshifts which are the next next biggest losers of ET in terms of acceleration performance.
& it follows that the massive aero-downforce tyre-grip F1 cars develop at racing speed - is not available at race start,
thus limiting the initial aceleration capability.
However, the AMZ is also limited - by its single speed (& falling torque output as speed rises), to a low terminal velocity,
& would soon be run down - by an F1 machine.
Re: Acceleration of F1 car
Posted: 19 May 2018, 10:24
by Tommy Cookers
the torque only falls with speed if the chief designer chooses to make it so
the electrics designer might prefer to have gears
Re: Acceleration of F1 car
Posted: 19 May 2018, 10:42
by J.A.W.
Are you sure about that T-C?
Isn't it a general principle that such a motor delivers max torque at stall, & then tapers off towards high rpm?
& the AMZ machine in question.. certainly appears to be a clutchless single speed.. & built as designed..
Do the ah, current math's - support the potential for an electrickery powered AWD dragster - to whip a top fuel machine?