Will C7 frame be all-aluminum?
10-12-2012, 02:07 PM
#41
10-12-2012, 02:11 PM
#42
Race Director
10-12-2012, 02:26 PM
#44
Race Director
10-12-2012, 05:19 PM
#45
Race Director
talked to a guy today who came across a test mule in a parking lot and looked it over. frame was steel. the rumor about that newer lighter steel gm was using would be my guess. also said the new car appeared to be narrower as the wheels were sunk in on the c6 skin that it was wearing
10-12-2012, 07:18 PM
#46
Le Mans Master
talked to a guy today who came across a test mule in a parking lot and looked it over. frame was steel. the rumor about that newer lighter steel gm was using would be my guess. also said the new car appeared to be narrower as the wheels were sunk in on the c6 skin that it was wearing
10-13-2012, 08:04 PM
#47
Burning Brakes
From the April, 2011 issue of 'Vette'
By Walt Thurn
excerpt -
"A new hydroformed frame (for the C6 Z06) was constructed from annealed, 4mm-thick 5745 aluminum alloy. The standard C5/C6 steel frame is 3 mm thick and weighs 502 pounds, while the Z06 frame is 4 mm thick and tips the scales at 392 pounds (22.5 percent lighter). Even better, the Z06 frame is 50 percent stronger in bending resistance and torsional stiffness. Continuing the theme of ongoing improvement, it's also the first car to use laser welding and self-piercing rivets in a mass-production environment. The final result is that the Z06 Corvette tips the scales at just 3,130 pounds.
Because of the car's low production volume, the aluminum frames are built at the Metalsa (formerly Dana Manufacturing) plant in Hopkinsville, Kentucky. The completed frames are then shipped to Bowling Green for final assembly. In 2009 the higher-performance ZR1 was added to the Corvette lineup; it uses the same Z06 aluminum frame built at the Metalsa plant."
Do I remember discussion that the $131 million being spent at Bowling Green could include moving the aluminum frame assembly into the plant? We can hope.
David
My C7 Website
By Walt Thurn
excerpt -
"A new hydroformed frame (for the C6 Z06) was constructed from annealed, 4mm-thick 5745 aluminum alloy. The standard C5/C6 steel frame is 3 mm thick and weighs 502 pounds, while the Z06 frame is 4 mm thick and tips the scales at 392 pounds (22.5 percent lighter). Even better, the Z06 frame is 50 percent stronger in bending resistance and torsional stiffness. Continuing the theme of ongoing improvement, it's also the first car to use laser welding and self-piercing rivets in a mass-production environment. The final result is that the Z06 Corvette tips the scales at just 3,130 pounds.
Because of the car's low production volume, the aluminum frames are built at the Metalsa (formerly Dana Manufacturing) plant in Hopkinsville, Kentucky. The completed frames are then shipped to Bowling Green for final assembly. In 2009 the higher-performance ZR1 was added to the Corvette lineup; it uses the same Z06 aluminum frame built at the Metalsa plant."
Do I remember discussion that the $131 million being spent at Bowling Green could include moving the aluminum frame assembly into the plant? We can hope.
David
My C7 Website
From SAE 2005-01-0466:
"The rails are fabricated from 4.0 mm thick 6063-T4 extruded tube and then artificially aged (to T5) prior to assembly into the structure." "The sheet components of the spaceframe structure are formed from a 5754-O material."
10-13-2012, 09:41 PM
#48
NEWS FLASH!!!!!!!!,,,the c7 frames are going to be made of balsa cored carbon-fiber and weigh less then 100 lbs,and the engine blocks are going to be titianuim-because of the GOV not building SR-71 Blackbirds anymore
10-15-2012, 11:07 PM
#49
Team Owner
talked to a guy today who came across a test mule in a parking lot and looked it over. frame was steel. the rumor about that newer lighter steel gm was using would be my guess. also said the new car appeared to be narrower as the wheels were sunk in on the c6 skin that it was wearing
10-16-2012, 12:25 AM
#50
Race Director
that would be my guess anyway. didn't ask for specifics
10-16-2012, 11:15 AM
#51
Team Owner
Is your buddy a welding expert? I don't think that many people can look at a weld and determine if the material was steel or aluminum that was welded.
10-18-2012, 12:49 AM
#52
Burning Brakes
Kinda a moot point since the helium thing probably isn't happening, but less weight IN the tires doesn't really mean very much less rolling resistance. Sprung weight will affect that much more than the air in the tires. If they really do weigh significantly less, then the main benefits will be less unsprung weight and less rotational inertia in the wheels.
10-18-2012, 09:40 AM
#53
Le Mans Master
I've often wondered about helium filled tires and I've read that it works except that the molecules are so small that it leaks out very quickly.
The idea is great though and reducing rotating weight, especially at the point furthest from the fulcrum, offers a large improvement in performance of all components.
The idea is great though and reducing rotating weight, especially at the point furthest from the fulcrum, offers a large improvement in performance of all components.
10-18-2012, 12:12 PM
#54
Drifting
Suns..
I've often wondered about helium filled tires and I've read that it works except that the molecules are so small that it leaks out very quickly.
The idea is great though and reducing rotating weight, especially at the point furthest from the fulcrum, offers a large improvement in performance of all components.
The idea is great though and reducing rotating weight, especially at the point furthest from the fulcrum, offers a large improvement in performance of all components.
Maybe some engineer can figure it out but here are the beginning facts...air is 78% nitrogen to begin with. Say a tire has seven liters of cubic space...the difference is a few grams at best and if you need more jammed in there to support the tire from inside, that might even be moot. Too scientific for me but I suspect it's straining at gnats.
Helium weighs 0.1785 grams per liter. Nitrogen weighs 1.2506 grams per liter, and since nitrogen makes up about 80 percent of the air we breathe, 1.25 grams is a good approximation for the weight of a liter of air.
10-18-2012, 01:31 PM
#55
Race Director
I'm too old and fat to crawl under a Corvette to look at the frame's welds and I don't have X-ray vision to enable me to look through the body to see the welds. Besides, I doubt if the "owners" of that car would let anyone walk up to the car and open the hood so they could get a good look at the frame, or remove the wheels so they could get a good look at the welds at the suspension attachment points, etc.
Is your buddy a welding expert? I don't think that many people can look at a weld and determine if the material was steel or aluminum that was welded.
Is your buddy a welding expert? I don't think that many people can look at a weld and determine if the material was steel or aluminum that was welded.
as the story goes the car was parked outside a burger joint. noticed the wheels looked off as they were sunk in. went over to the car, poked his head under and noticed different looking suspension than his c6 along with the steel frame. at that point the guess became a c7 frame and running gear with c6 skin.
as the story goes, shortly there after the GM guys walked out, didn't say much but did mention that hardly anyone catches the difference
10-18-2012, 01:58 PM
#56
Team Owner
i can. it's actually really easy if you've ever welded before. they look night and day different
as the story goes the car was parked outside a burger joint. noticed the wheels looked off as they were sunk in. went over to the car, poked his head under and noticed different looking suspension than his c6 along with the steel frame. at that point the guess became a c7 frame and running gear with c6 skin.
as the story goes, shortly there after the GM guys walked out, didn't say much but did mention that hardly anyone catches the difference
as the story goes the car was parked outside a burger joint. noticed the wheels looked off as they were sunk in. went over to the car, poked his head under and noticed different looking suspension than his c6 along with the steel frame. at that point the guess became a c7 frame and running gear with c6 skin.
as the story goes, shortly there after the GM guys walked out, didn't say much but did mention that hardly anyone catches the difference
Can you tell the difference in the welds, steel vs aluminum, if both are coated black?
10-18-2012, 02:10 PM
#57
Race Director
as for the welds
notice the spearco intercooler, that's aluminum welding. fat bead, pulse is different
this is steel
see what i mean? cosmetics are night and day different. both tig welds
Last edited by racebum; 10-18-2012 at 02:13 PM.
10-18-2012, 02:15 PM
#58
Le Mans Master
The older debate is the merit of using all nitrogen instead of "air" which is 78% nitrogen. It strikes me that the discussion about helium instead is worrying about something to the 6th standard deviation of effect, if that. The physics of lighter further from the center are true but the rubber in the tire far outweighs the atmosphere inside. I'm no engineer but if helium weighs less it's probably because it is less dense. To keep enough helium atmosphere to keep the pressure required to keep the tire from collapsing would probably require much more helium be pumped in to support it wouldn't it? If so would that then not add more molecules and weight to start with? I'm no engineer but the whole discussion seems like discussing something which would have virtually little or no practical, noticable impact to me.
Maybe some engineer can figure it out but here are the beginning facts...air is 78% nitrogen to begin with. Say a tire has seven liters of cubic space...the difference is a few grams at best and if you need more jammed in there to support the tire from inside, that might even be moot. Too scientific for me but I suspect it's straining at gnats.
Helium weighs 0.1785 grams per liter. Nitrogen weighs 1.2506 grams per liter, and since nitrogen makes up about 80 percent of the air we breathe, 1.25 grams is a good approximation for the weight of a liter of air.
Maybe some engineer can figure it out but here are the beginning facts...air is 78% nitrogen to begin with. Say a tire has seven liters of cubic space...the difference is a few grams at best and if you need more jammed in there to support the tire from inside, that might even be moot. Too scientific for me but I suspect it's straining at gnats.
Helium weighs 0.1785 grams per liter. Nitrogen weighs 1.2506 grams per liter, and since nitrogen makes up about 80 percent of the air we breathe, 1.25 grams is a good approximation for the weight of a liter of air.
The only advantage of Nitrogen is that since it is hydrophobic (doesn't get water mixed in) the amount of moisture in the N2 doesn't vary. Therefore the pressure rise is predictable as temps rise. All gases expand when heated per Boyle's law, it's just that the amount can vary when moisture is added. I try to offset this effect by choosing to buy and refill tires on very low humidity days. Not easy to pull off here in Texas.
As far as helium weight savings. Well first, no it doesn't require more molecules to achieve the same pressure w/ different gases. The weight of the gas is usually listed per CFM and to fill a certain space to a certain pressure will require the same CFMs regardless of the gas used.
Hum a cursury look at the volume of air of a large tire like a Vette I get about 5 CF to get to 32psi. I noticed on top of a urinal earlier that it had "1gpf/ 3.8lpf" stamped on it's top. So I get 19 Cubic liters in this same tire (5 x 3.8). If Air weighs 1.25 grams per liter, then we get basically 24 grams of air per tire, or .05 of a single pound. If you do the calculation on the helium it weighs about .007# leaving a net difference of about .45# per wheel end. Not much. So even if you had no air in each tire, it wouldn't even save 2# for 4 wheel ends. You will never get no air in a tire because when you mount them, they already have a lot of air just hanging out in there. So you might as well cut that number in half so now you've lost a single pound for a bunch of expense and trouble.
Yah, this is an idea that has no merit.
10-18-2012, 03:01 PM
#59
Team Owner
The only advantage of Nitrogen is that since it is hydrophobic (doesn't get water mixed in) the amount of moisture in the N2 doesn't vary. Therefore the pressure rise is predictable as temps rise. All gases expand when heated per Boyle's law, it's just that the amount can vary when moisture is added. I try to offset this effect by choosing to buy and refill tires on very low humidity days. Not easy to pull off here in Texas.
As far as helium weight savings. Well first, no it doesn't require more molecules to achieve the same pressure w/ different gases. The weight of the gas is usually listed per CFM and to fill a certain space to a certain pressure will require the same CFMs regardless of the gas used.
Hum a cursury look at the volume of air of a large tire like a Vette I get about 5 CF to get to 32psi. I noticed on top of a urinal earlier that it had "1gpf/ 3.8lpf" stamped on it's top. So I get 19 Cubic liters in this same tire (5 x 3.8). If Air weighs 1.25 grams per liter, then we get basically 24 grams of air per tire, or .05 of a single pound. If you do the calculation on the helium it weighs about .007# leaving a net difference of about .45# per wheel end. Not much. So even if you had no air in each tire, it wouldn't even save 2# for 4 wheel ends. You will never get no air in a tire because when you mount them, they already have a lot of air just hanging out in there. So you might as well cut that number in half so now you've lost a single pound for a bunch of expense and trouble.
Yah, this is an idea that has no merit.
As far as helium weight savings. Well first, no it doesn't require more molecules to achieve the same pressure w/ different gases. The weight of the gas is usually listed per CFM and to fill a certain space to a certain pressure will require the same CFMs regardless of the gas used.
Hum a cursury look at the volume of air of a large tire like a Vette I get about 5 CF to get to 32psi. I noticed on top of a urinal earlier that it had "1gpf/ 3.8lpf" stamped on it's top. So I get 19 Cubic liters in this same tire (5 x 3.8). If Air weighs 1.25 grams per liter, then we get basically 24 grams of air per tire, or .05 of a single pound. If you do the calculation on the helium it weighs about .007# leaving a net difference of about .45# per wheel end. Not much. So even if you had no air in each tire, it wouldn't even save 2# for 4 wheel ends. You will never get no air in a tire because when you mount them, they already have a lot of air just hanging out in there. So you might as well cut that number in half so now you've lost a single pound for a bunch of expense and trouble.
Yah, this is an idea that has no merit.
10-18-2012, 04:19 PM
#60
Le Mans Master
Member Since: Jul 2000
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The Helium thing was a JOKE.
Also there is a reason physics uses mass instead of weight. A blimp could have a mass of 100 tons and still float away (i.e. no weight). However the handling dynamics would be dictated by the mass of (metric) 100 tons (1,000 kilograms).
And yes Helium would migrate through the rubber of the tire. Of course I made my ruse more believable by saying they would coat the inside of the tire with Mylar.
Also there is a reason physics uses mass instead of weight. A blimp could have a mass of 100 tons and still float away (i.e. no weight). However the handling dynamics would be dictated by the mass of (metric) 100 tons (1,000 kilograms).
And yes Helium would migrate through the rubber of the tire. Of course I made my ruse more believable by saying they would coat the inside of the tire with Mylar.
Last edited by Racer X; 10-18-2012 at 09:15 PM. Reason: Saving my post from a stupid error.
