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An audiophile and petrolhead's journal: Buckle up! - Page 113

post #1681 of 9498
It's true that the car has rolling resistance to deal with - and "downforce" is really just negative lift. If you cut a Formula 1 or Indy car down the centerline and look at the shape of the cross-section, you will see a shape with a lot of similarities to an inverted airfoil. The total drag on a airplane at a low cruise speed can be lower than a car - but cruising in a car is also fairly easy - all the HP in cars is to get the car going and to keep it accelerating at the top-end. Cruising along at 60 MPH doesn't require a great deal of HP in either a car or an airplane.

On the other hand, the speed and properties of the air are MUCH more simple for a car than for an airplane. In a car (excluding the Thrust SSC and similar land jets/rockets), you don't need to deal with large variations in ambient pressure or air density - and you don't have to deal with transonic effects of flying at Mach 0.80+ like your average Boeing 737.

And then we could talk about stability & control and the difficulty of just keeping the plane flying straight & level. wink.gif
post #1682 of 9498
Thread Starter 
I did forget to mention, the shop bought a `69 Mach 1 to make an Elanor replica. Should be cool.
post #1683 of 9498

The way I see it, a high performance car like the F1 is a balancing act, two different types of interactions, because downforce needs to be increased while reducing drag.

A plane, well, its just improvement in one field. I agree, high performance planes are inherently instable systems that need constant control (hence computers and fly-by-wire), but modern cars are also similar, needing active suspension, adaptive aerodynamics and what not.

 

Oh, and the book (now I remember) was Tune to Win (Carroll Smith).


Edited by proton007 - 1/23/13 at 12:30am
post #1684 of 9498
Because so much speed is lost while cornering, and the time spent at top speed is relatively short, the downforce actually plays a much more important role in lap time than the drag reduction. F1 designers will give up drag to get more downforce - the only thing really limiting their downforce are the rules for the size of the wings, not being allowed to use moveable skirts, no vertical fans, etc. what this means is that they design for maximum legal (or sometimes mostly legal) downforce first, then make that car design as low-drag as possible.

The most you will get me to agree to is that both high performance car and airplanes are incredibly complex machines. They have completely different design criteria. Of course, if you screw-up the car design or break-down in your car, you won't go spiraling down to a fiery death from 40,000 ft. You will just coast to the side of the road and wait for the tow truck... wink.gif
post #1685 of 9498
A buddy of mine had a Mach 1 'stang in high school. Unfortunately, it wasn't a '69 - it was probably the ugliest of all the old Mustangs - a 1972 (I think) Mach 1 with the anemic & smog-control choked 302. That thing was a pretty horrible car - it rattled and shook like a Wile E. Coyote robot and the visibility from inside the car awful - between the long hood, low roof, low seat position, high dash and giant roof pillars, you could barely see out of the thing. But - it was still cool... tongue.gif
post #1686 of 9498
Speaking of F1 rules, this reminds me of one of my pet peeves about most forms of auto racing (or any pro sports) - rules. I think all forms of pro sports need to have an "unlimited" category where there are NO rules on design. Rules based on "safety" or to "slow the cars down" in the top classes like F1 (road racing) or Indycars (oval racing) makes no sense to me. If someone wants to take the risk - I say let 'em. If they want to run a nuclear-powered car using technology captured from visiting aliens from Beetlegeuse, fine - go for it.

And before someone says it - no - I am NOT talking about Death Race - no machine guns or other nastiness against your fellow racers - but I think there needs to be somewhere where the engineers are allowed to think completely outside the box. I guess the closest we have to that is a top-fuel dragster - but even there they had to create a separate class for jet cars. Other than land speed record cars, the only place I can think of that is pretty much "no rules" is unlimited tractor pulling. Those beasts are wild! Multiple turbine engines, 6 x supercharged Allisons or Merlins and hybrids with both! Unlimited tractor pulling is now VERY popular worldwide. When I was a kid, you only saw it at rural county fairs, and someone with 1 turbine engine or 1 V12 Allison was considered unbelievably exotic.

post #1687 of 9498
Actually tractor pulling "unlimited class" has restrictions on it - at least in the US. There's restrictions imposed on weight and dimensions.
http://www.ntpapull.com/index.php?option=com_content&view=category&layout=blog&id=267&Itemid=100268

So for example you can't hook up a pair of GE CF6's "Pod Racer style" and go at it. There's also limitations on how they contact the ground (tire size), so you can't just roll up in an M1 and have at it. And this will eventually circle back to your "restrictions keeping engineers blocked" point - you can only get so much power transfer through the spec tires, and only so large of an engine into the 8000 lbs weight limit and size restrictions.
Edited by obobskivich - 1/23/13 at 3:59pm
post #1688 of 9498
Yeah - I guess you are right. I remember in the old days the same vehicles would be in two weight classes, and they would just hang extra weights on the tractor for the higher weight class. But, that was before they just kept adding more engines...

Then again, I would probably be OK with another class above unlimited where pod racers and M1 tanks were allowed. NASA is probably looking for someone willing to buy this baby:


post #1689 of 9498
Quote:
Originally Posted by billybob_jcv View Post

Yeah - I guess you are right. I remember in the old days the same vehicles would be in two weight classes, and they would just hang extra weights on the tractor for the higher weight class. But, that was before they just kept adding more engines...

Then again, I would probably be OK with another class above unlimited where pod racers and M1 tanks were allowed. NASA is probably looking for someone willing to buy this baby:



Isn't there a time limit on how long the thing can pull too? (I couldn't find anything about that on the NPTA website)

I'm also not sure how that thing's power would translate into pull strength - I mean they're big, but they're also super heavy (they weigh something like 3000 tons each), and super slow, and while they rely on electric motors for traction, their overall output is about in-line with a conventional pull tractor (think about this both ways).

I think you'd do better with a locomotive MU running on treads, or taking one of those absolutely MASSIVE Wartsila engines and throwing that on wheels. Like this big monster:
http://www.wartsila.com/en/engines/low-speed-engines/RT-flex96C

Here's its power plot:


For the Americans, that scale is roughly 75,000 - 108,000 hp.

The only problem is that it's designed to go in this:


And weighs around as much as the shuttle crawler for just the engine. Oh yeah, and it's around a third the length of a football field. Pretty sure the sled wouldn't know what hit it though. very_evil_smiley.gif

Oh, and just because this discussion is quickly on the way there already, and I need to honor Mr Taylor.

Edited by obobskivich - 1/23/13 at 4:54pm
post #1690 of 9498
Quote:
Originally Posted by billybob_jcv View Post

Speaking of F1 rules, this reminds me of one of my pet peeves about most forms of auto racing (or any pro sports) - rules. I think all forms of pro sports need to have an "unlimited" category where there are NO rules on design. Rules based on "safety" or to "slow the cars down" in the top classes like F1 (road racing) or Indycars (oval racing) makes no sense to me. If someone wants to take the risk - I say let 'em. If they want to run a nuclear-powered car using technology captured from visiting aliens from Beetlegeuse, fine - go for it.


The problem with F1 has been that its too fast for the driver. And F1 hasn't been the most difficult of them all, with their semi-auto gearboxes, smooth tracks and emphasis on safety.

 

If you really want a taste of what driving on the edge is like, take a look at Group B Rally. Its been popularly know as 'too fast to race'. Little restrictions, purpose built rally cars with close to F1 levels of performance.

 

 

Then there's group C (the likes of Porsche 956) that still holds the record at Nurburgring, equally fast. Some say it was killed because it became too popular, started competing with F1 in terms of viewership.

 

 

The same thing happened with FIA GT, when Mercedes came up with the CLK GTR. They absolutely obliterated everyone, and no one wanted to compete anymore because the CLK was miles ahead in terms of performance.

 

 

So I guess its two things. First, learning the hard way that brute force wasn't the way to go. The F1 and WRC cars today achieve similar lap times as the cars of those era, albeit with less power and more control. I think its good for designers to work in constraints, because then the boundaries to push are well defined.

 

Secondly, politics and money comes in the picture. Some teams have a stupendous amount of money to spend, and if it isn't for these restrictions, they would keep making better cars than the rest of them and keep winning. (Ferrari + Schumacher).


Edited by proton007 - 1/23/13 at 5:08pm
post #1691 of 9498
Quote:
Originally Posted by obobskivich View Post


Isn't there a time limit on how long the thing can pull too? (I couldn't find anything about that on the NPTA website)

I'm also not sure how that thing's power would translate into pull strength - I mean they're big, but they're also super heavy (they weigh something like 3000 tons each), and super slow, and while they rely on electric motors for traction, their overall output is about in-line with a conventional pull tractor (think about this both ways).

I think you'd do better with a locomotive MU running on treads, or taking one of those absolutely MASSIVE Wartsila engines and throwing that on wheels. Like this big monster:
http://www.wartsila.com/en/engines/low-speed-engines/RT-flex96C

Here's its power plot:


For the Americans, that scale is roughly 75,000 - 108,000 hp.

The only problem is that it's designed to go in this:


And weighs around as much as the shuttle crawler for just the engine. Oh yeah, and it's around a third the length of a football field. Pretty sure the sled wouldn't know what hit it though. very_evil_smiley.gif

Oh, and just because this discussion is quickly on the way there already, and I need to honor Mr Taylor.


Haha. Those engines...a person could comfortably stand in one of those cylinders, they're huge.

post #1692 of 9498
My problem with the race rules are that it has become easier to get something outlawed than it is to engineer something new and better. That's a recipe for stagnation.

obob: consider the weight of the shuttle and launch platform that the NASA vehicle has to move. It is moving that weight, from a standstill, in the worst possible conditions - all the weight is right over the tracks. A tractor pull sled moves the weight forward to put more and more weight on the tractor's wheels. It actually has an easier time because it has some momentum going before the weight reaches it's maximum. According to Wikipedia, the latest upgrade increases the lifting capacity (meaning it can lift it then move forward) to 18,000,000 pounds! Now - does being able to lift and move forward with 18M pounds on your back correspond to being able to drag 18M pounds? If the surface was frictionless, I think it would, but it isn't. If I was still half an engineer, this would be an easy problem - but it's been too long and too many years in management has killed far too many brain cells... redface.gif
post #1693 of 9498
Thread Starter 
Never was into tractor pulls or Gravedigger type stuff, I've always been a speed freak. I can appreciate the engineering that goes into Monster trucks, bu the sport itself doesn't do much for me. redface.gif


It seems that the Mustang the shop bought was a 70, not a 68. Way to read the title, guys. rolleyes.gif The good news is, it was originally a Boss, though it's kinda hard to tell.

H|?

Okay, yeah, I can see how it could be hard to identify this...
post #1694 of 9498
Yikes. They might have been better off starting with a Dodge Charger and making a Eleanor from that... tongue.gif

Hmm - as I recall, the original Eleanor was a long-hood mid 70's Mustang (maybe a '72 or '73?), and the Nick Cage Eleanor was a '67 Fastback. What are you going to do with a '70? How about the Trans-Am version of the Boss 302? The Parnelli Jones 1970 Boss 302 would be perfect!




Check this out to see the size of the cajones on Parnelli Jones...

post #1695 of 9498
Thread Starter 
Quote:
Originally Posted by billybob_jcv View Post

Yikes. They might have been better off starting with a Dodge Charger and making a Eleanor from that... tongue.gif

Hmm - as I recall, the original Eleanor was a long-hood mid 70's Mustang (maybe a '72 or '73?), and the Nick Cage Eleanor was a '67 Fastback. What are you going to do with a '70? How about the Trans-Am version of the Boss 302? The Parnelli Jones 1970 Boss 302 would be perfect!




Check this out to see the size of the cajones on Parnelli Jones...

That's some nutty stuff, yikes. blink.gif

That's not as bad as it looks, haha. We have the doors and other panels, but not the nose and bumper. I think we're going to go with a complete resto mod on the Mustang, an old/new hybrid. A BB Alu 428, stroked and bored out to 518ci with Comp roller cams, and X-FI EFI system netting ~750bhp. Then add big Brembo discs all around, locking LSD w/ 4.11 gear, Tremec T-56 6-spd gearbox, and independent electro-mag suspension. So, it'll be a `70 Boss 428 EFI, probably.

Yeah, the first Elanor was a `73 Mach 1, the remake Elanor was a `68 GT. At least the `70 Boss had more in common with the late 60s cars than the early 70s. Not that they were awful, but all the gov't restrictions messed up all muscle cars, not just the Mustang.


After not getting a definitive answer from McLaren on running E85 in the MP4, "it has not been fully tested with that fuel and we cannot guarantee its performance", yadda, yadda. I went ahead and filled it up to see what would happen. Well, nothing happened. That is to say I couldn't tell any difference between running it and 93 premium, in fact it ran like the 100oct fuel. According to the on-board system it looks like I'm getting a couple MPG less, but given the price and availability (I keep E85 in the tank here at home), it seems well worth it to me. I wouldn't say it will run like that with all E85 brands, some are pretty dodgy, but the Sunoco stuff is very good.

Also, even though it doesn't get noticed as much as the 458, which can be a good thing (cops), it does get quite a few compliments. A guy did ask "aren't you afraid it will get stolen?" and I said, "It's the only red McLaren within 500 miles, where will they hide?" wink.gif Also, there's GPS tracking, dual alarm systems, and a pick-proof electromagnetic lock. (Yes, I ordered 2 extra fobs, just in case.)
Edited by Magick Man - 1/23/13 at 10:19pm
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