Designing the composite hood

[ViperSmith]

Can someone explain to me how a $40k markup on a car that costs $100k is different that a $7 potato going to $11? If anything the potato getting one over on you more...

I'd love to see what store sells to idiots $7 potatoes! My local Whole Foods sells football sized potatoes for $.50 a pound

 

[kratedisease]

Can someone explain to me how a $40k markup on a car that costs $100k is different that a $7 potato going to $11? If anything the potato getting one over on you more...

Sure, let me explain.....since you asked......

The $7 potato that they serve at RuthChris costs 39 cents to buy if you are only calculating the potato uncooked. But add in rent, salaries, ovens, gas, electric, workers comp, etc it costs around $4 by the time it gets to the table. The $7 is the retail price including profit.

The $100,000 Viper that they sell at the SRT dealer also costs around $40,000 if you are only calculating the raw materials used to manufacture the parts. Add in overhead, salaries, gas , electric, workers comp, tooling costs, development and engineering costs, and the cost of the drug rehab benefit that Chrysler offers its workers because we all know they are high on the assembly line, and you end up with a car that is around $80,000. Then add in Chryslers profit and the dealers are getting them for around $89,000.

Wow, I am tired from all this typing.... I am going to see if I have a tombstone pizza I can heat up......

 

[Voice of Reason]

Since this is a bit more of SRTViper's league:

The base Mustang costs $22,200

What exotic materials in the GT500 command the $55,000 MSRP?

Surely there must be $32,000 worth of something special in your car to command a $32,000 price difference.

Seeing as you can only justify cost as material costs (Since R&D is free!) - what are the cost differences in them? Is the block of a more exotic material?

Please, I'd love to hear. Remember, you can only price things by material cost!

+1! I want to read how he justifies this too.

 

[viper GTS-R]

Damn...I'm somewhat gutted cause was kinda hoping to be the first to write that article.

Anyway, I'm actually up here in Vermont right now (took the Dart Aero on it's first major road trip, it made 37 MPG fully loaded) and I plan on meeting with Plasan sometime during the week and possibly Tators on the way home. So if you guys have any questions maybe I can get them answered.

--RS

 

[SRTviper]

Since this is a bit more of SRTViper's league:

The base Mustang costs $22,200

What exotic materials in the GT500 command the $55,000 MSRP?

Surely there must be $32,000 worth of something special in your car to command a $32,000 price difference.

Seeing as you can only justify cost as material costs (Since R&D is free!) - what are the cost differences in them? Is the block of a more exotic material?

Please, I'd love to hear. Remember, you can only price things by material cost!

The answer is obvious. The engine in my car cost 30k alone. That is exactly what you are paying for. A v6 with a awesome engine.

I'd love to see what store sells to idiots $7 potatoes! My local Whole Foods sells football sized potatoes for $.50 a pound

I can't believe I'm about to argue about potato cost with you, clearly I have sunk to the same low and stupidity as you but lets be honest. You may be able to lie on this forum to these people but since we live near each other you can't lie to me. There is no whole foods on the planet that sells anything for 50 cents let alone a pound of potatoes. A pound of potatoes is like 4 dollars at giant and 5 at whole foods. And if you want sweet potatoes or the little small dinner ones that come already in the bag it is more.

Now I'm just ashamed I had to argue with an idiot about potato prices.

 

[MoparMap]

... Racecar manufacturers have also developed methods to give carbon fiber pieces strength in a certain direction, making it strong in a load-bearing direction, but weak in directions where little or no load would be placed on the member. Conversely, manufacturers developed omnidirectional carbon fiber weaves that apply strength in all directions...

There are a few misconceptions about carbon fiber that I think this article helps to clear up. I took a few semesters of composite design in my grad school work and had my eyes opened quite a bit regarding carbon design. The big thing about carbon fiber is that it is only really strong along the fibers. It's like wood grain, if you pull along it, it's stronger than steel, but if you pull across it, it's only as strong as the binder in it (epoxy, resin, plastic, etc.). The weave helps to alleviate this and provide some strength in different directions, but you still have less strength if you are off either axis. Typically a panel will have 0, 90, and +-45 degree layers, but still you'll have some angles inbetween that are missed. However, by the time you stack enough layers to get strength in all the directions you need, you have a really thick part that isn't cost effective and isn't necessarily that much stronger than other materials in certain loadings. One way to get a nearly isotropic (same properties in all directions) material is chopped mat style composites. You basically chop up tons of fibers so they're going all sorts of directions and embed them in a matrix (like plastic). This is what I tend to think of when I hear CFRP, it's just plastic with carbon strands running around everywhere. It makes for a very stiff part, but not necessarily strong. For what it's worth, I'm pretty sure my old 71 Corvette is chopped mat fiberglass as I've sanded through the gel coat when repainting the car and can see the strands running around in all directions.

The bigger point in all of this is that body panels don't really need to be strong. Do you think that the hood hinge and two pins at the back are going to tie your hood into your chassis so much that it will increase the rigidity of the chassis by much? I just took off a rear fender and bumper on my car and they're floppy pieces of plastic that are only attached at a few points. Do I think this is cheap? Nope, I know that the only real function of the panels on this car is aerodynamics. All they really have to do is withstand whatever wind loads and air pressures are put on them. They do NOTHING to make my car any stiffer, that's what the monster frame under the car is for. Other supercars that use monocoque (aka unibody) design use the passenger compartment as a structural member, so they might prefer to use woven composites. If you've ever seen the "factory made" show or whatever it's called where they build the Viper you'll see that the car is fully functional without any body panels at all. They are not integral to the structure of the car, so they could be made of paper mache and work just as well.

Carbon fiber is really just a buzzword that gets people's trousers burning. It's not really the cure-all that people seem to think. Typically speaking, if you want to build something efficiently with carbon fiber you need to know exactly how it will be loaded. On a street car I'd say that's nearly impossible. You'll never know what kind of roads and conditions the car will be put under, so you have to overbuild it significantly, which makes it not cost effective anymore. Also, it tends to fail catastrophically. Metal will bend and absorb energy when failing, but composites tend to just shatter.

 

[Nine Ball]

The answer is obvious. The engine in my car cost 30k alone. That is exactly what you are paying for. A v6 with a awesome engine.

The Mustang V6 engine is constructed of aluminum, steel, some other alloys and plastic.

Your GT500 engine is also made of the same materials.

Sorry, your Mustang is overpriced. They use the same materials for all the engines.

 

[SRT Engineers]

Quick note to set the record straight on this.

In the industry "Carbon Fiber" is almost always an interchangeable term with "CFRP" (Carbon Fiber Reinforced Plastic or Polymer). It is indeed the same thing. Also sometimes refered to as "graphite", carbon fiber in it's raw form is very strong in tension (like pulling on a rope) but is very week in compression (like pushing on a rope). CFRP takes the raw dry fiber and makes it strong in compression. The Viper uses some of the highest quality pre-preg carbon fiber available. We use various types of pre-preg carbon fiber depending on the area of the part. Woven carbon fiber is used on the inner panel to distribute the material properties and for a nice decorative finish. Unidirectional fiber is used on the outer skin because it will not 'read-out' the pattern like the weave will. Aerospace does the same thing. Sometimes carbon is woven, and sometimes it is countinuous or uni-directional.

Just want to put a stop to any rumors that your Gen-V Vipers are not built with the genuine carbon fiber!!

 

[ViperSmith]

Quick note to set the record straight on this.

In the industry "Carbon Fiber" is almost always an interchangeable term with "CFRP" (Carbon Fiber Reinforced Plastic or Polymer). It is indeed the same thing. Also sometimes refered to as "graphite", carbon fiber in it's raw form is very strong in tension (like pulling on a rope) but is very week in compression (like pushing on a rope). CFRP takes the raw dry fiber and makes it strong in compression. The Viper uses some of the highest quality pre-preg carbon fiber available. We use various types of pre-preg carbon fiber depending on the area of the part. Woven carbon fiber is used on the inner panel to distribute the material properties and for a nice decorative finish. Unidirectional fiber is used on the outer skin because it will not 'read-out' the pattern like the weave will. Aerospace does the same thing. Sometimes carbon is woven, and sometimes it is countinuous or uni-directional.

Just want to put a stop to any rumors that your Gen-V Vipers are not built with the genuine carbon fiber!!

Guys, only a troll is trying to spread this stupidity. We greatly appreciate you chiming in.

 

[Voice of Reason]

The answer is obvious. The engine in my car cost 30k alone. That is exactly what you are paying for. A v6 with a awesome engine.

I've grown tired of your arguing out of both sides of your mouth. With that you're on my ignore list.

 

[ViperSmith]

Edit: removed troll fodder

 

[BlackSnake99]

Organic potatoes are tearing this board apart.



PS- It's a RUSSET potato, but I digress....

 

[The_Greg]

EDIT: Removed troll fodder.

 

[Nine Ball]

And all of this was an exercise to see if you'd actually argue the price of a damned baked potato, which you have.

I'd classify SRTViper as another type of troll. We call them "Contrarian". With anything said, this type of troll will look for something to say to the contrary. Even if he agrees with a statement, the "Contrarian" troll will find fault with it.

 

[Policy Limits]

blocked him a while ago

 

[ACRucrazy]

Has anyone bought one that you know of?
I think I will try tomorrow

Also that website does not even list SRT the hood says Dodge p/n
Just doesn't seem like it can be either hood

I called my good buddy at the dealer. The SRT hood supersedes to a new PN 6819948AD, currently 3 on back order. List is $3,070 for the old and new number.

 

[kratedisease]

Organic potatoes are tearing this board apart.



PS- It's a RUSSET potato, but I digress....

I could not agree more.... if potatoes never came into the discussion this would have never happened....


Everyone should know, never talk politics, religion or potatoes or tempers will flair ...

peace out

 

[JETSTAR]

Has anyone bought one that you know of?
I think I will try tomorrow

Also that website does not even list SRT the hood says Dodge p/n
Just doesn't seem like it can be either hood

Called up my local dealer and ordered a SRT and GTS hood both are on back order. I still don't think the price is right

 

[ACRucrazy]

See my earlier post from today.

I called my good buddy at the dealer. The SRT hood supersedes to a new PN 6819948AD, currently 3 on back order. List is $3,070 for the old and new number.

 

[ViperSmith]

See my earlier post from today.

i'd be curious, is it the composite hood assembly, the outer shell and the inner "pretty" carbon fiber?

 

[SRTviper]

The Mustang V6 engine is constructed of aluminum, steel, some other alloys and plastic.

Your GT500 engine is also made of the same materials.

Sorry, your Mustang is overpriced. They use the same materials for all the engines.

Sorry the shelby engine is all aluminum and has fully forged internals. It is the engine from the 140k FGT taken up a notch. It resembles nothing from the v6 or 5.0 engines. The viper just finally got forged internals.

Quick note to set the record straight on this.

In the industry "Carbon Fiber" is almost always an interchangeable term with "CFRP" (Carbon Fiber Reinforced Plastic or Polymer). It is indeed the same thing. Also sometimes refered to as "graphite", carbon fiber in it's raw form is very strong in tension (like pulling on a rope) but is very week in compression (like pushing on a rope). CFRP takes the raw dry fiber and makes it strong in compression. The Viper uses some of the highest quality pre-preg carbon fiber available. We use various types of pre-preg carbon fiber depending on the area of the part. Woven carbon fiber is used on the inner panel to distribute the material properties and for a nice decorative finish. Unidirectional fiber is used on the outer skin because it will not 'read-out' the pattern like the weave will. Aerospace does the same thing. Sometimes carbon is woven, and sometimes it is countinuous or uni-directional.

Just want to put a stop to any rumors that your Gen-V Vipers are not built with the genuine carbon fiber!!

I never said it didn't have genuine carbon fiber but please explain to me then the different because by the videos I posted what you are saying doesn't seem correct. In the BMW video you could clearly see how the factory took a huge sheet of carbon fiber and put it on the plastic piece and then put it in the oven that bonded them together.

Then in the agera R video you could clearly see there was no plastic sheet bonded to carbon fiber. The carbon fiber on it's own was put in the billet aluminum mold and formed to make the part. Being put in the aluminum mold is what forced the carbon fiber into the intake shape. I know aerospace and boats use CFRP but what you are saying is there is no difference. But the videos I posted very very clearly shows there is a difference. So please explain to me the difference between the videos I posted that are not already obviously apparent.

I apparently must be missing something because what I saw was one video had them bond it to plastic (CFRP) and the other they did not. And it kinda makes sense in the name carbon fiber reinforced plastic is that it is carbon fiber reinforced with plastic (not really creative when they made that name huh?)

 

[kratedisease]

There are a few misconceptions about carbon fiber that I think this article helps to clear up. I took a few semesters of composite design in my grad school work and had my eyes opened quite a bit regarding carbon design. The big thing about carbon fiber is that it is only really strong along the fibers. It's like wood grain, if you pull along it, it's stronger than steel, but if you pull across it, it's only as strong as the binder in it (epoxy, resin, plastic, etc.). The weave helps to alleviate this and provide some strength in different directions, but you still have less strength if you are off either axis. Typically a panel will have 0, 90, and +-45 degree layers, but still you'll have some angles inbetween that are missed. However, by the time you stack enough layers to get strength in all the directions you need, you have a really thick part that isn't cost effective and isn't necessarily that much stronger than other materials in certain loadings. One way to get a nearly isotropic (same properties in all directions) material is chopped mat style composites. You basically chop up tons of fibers so they're going all sorts of directions and embed them in a matrix (like plastic). This is what I tend to think of when I hear CFRP, it's just plastic with carbon strands running around everywhere. It makes for a very stiff part, but not necessarily strong. For what it's worth, I'm pretty sure my old 71 Corvette is chopped mat fiberglass as I've sanded through the gel coat when repainting the car and can see the strands running around in all directions.

The bigger point in all of this is that body panels don't really need to be strong. Do you think that the hood hinge and two pins at the back are going to tie your hood into your chassis so much that it will increase the rigidity of the chassis by much? I just took off a rear fender and bumper on my car and they're floppy pieces of plastic that are only attached at a few points. Do I think this is cheap? Nope, I know that the only real function of the panels on this car is aerodynamics. All they really have to do is withstand whatever wind loads and air pressures are put on them. They do NOTHING to make my car any stiffer, that's what the monster frame under the car is for. Other supercars that use monocoque (aka unibody) design use the passenger compartment as a structural member, so they might prefer to use woven composites. If you've ever seen the "factory made" show or whatever it's called where they build the Viper you'll see that the car is fully functional without any body panels at all. They are not integral to the structure of the car, so they could be made of paper mache and work just as well.

Carbon fiber is really just a buzzword that gets people's trousers burning. It's not really the cure-all that people seem to think. Typically speaking, if you want to build something efficiently with carbon fiber you need to know exactly how it will be loaded. On a street car I'd say that's nearly impossible. You'll never know what kind of roads and conditions the car will be put under, so you have to overbuild it significantly, which makes it not cost effective anymore. Also, it tends to fail catastrophically. Metal will bend and absorb energy when failing, but composites tend to just shatter.

Thank you for your comprehensive explanation....

 

[I Bin Therbefor]

Tid Bit from the article

"our projected peak volumes [2,500 units/annually]"

That's what the suppliers are using for production projections, manufacturing techniques, and capital equipment investments. Fits the more informal comments by Ralph G. As I recall, ~1500 units/annually are needed for profitability.

 

[Newport Viper]

Wait for it.... wait










There it is!

You must be registered for see images

This thread is soooooo much cooler now!

 

[VYPR BYT 94]

Guys stop it...
somebody on the vette forum is posting our viper is using potato-reinforced dash assemblies.

This is a nightmare of organic proportions!

 

[Steve M]

Sorry the shelby engine is all aluminum and has fully forged internals. It is the engine from the 140k FGT taken up a notch. It resembles nothing from the v6 or 5.0 engines. The viper just finally got forged internals.

You might want to take a refresher course on Viper history...

Oh, and you're doing it again.

 

[Hemotoxic]

Sure, let me explain.....since you asked......

The $7 potato that they serve at RuthChris costs 39 cents to buy if you are only calculating the potato uncooked. But add in rent, salaries, ovens, gas, electric, workers comp, etc it costs around $4 by the time it gets to the table. The $7 is the retail price including profit.

The $100,000 Viper that they sell at the SRT dealer also costs around $40,000 if you are only calculating the raw materials used to manufacture the parts. Add in overhead, salaries, gas , electric, workers comp, tooling costs, development and engineering costs, and the cost of the drug rehab benefit that Chrysler offers its workers because we all know they are high on the assembly line, and you end up with a car that is around $80,000. Then add in Chryslers profit and the dealers are getting them for around $89,000.

Wow, I am tired from all this typing.... I am going to see if I have a tombstone pizza I can heat up......

Aha, so what you're saying is:

Viper parts are made from CFRP (Carbon Fiber Reinforced Potatoes) sliced thinly and kettle-cooked in hydrogenated vegetable oil.

Thank you for the enlightenment. I need to go bust open a can of Pringles now.

 

[kratedisease]

Aha, so what you're saying is:

Viper parts are made from CFRP (Carbon Fiber Reinforced Potatoes) sliced thinly and kettle-cooked in hydrogenated vegetable oil.

Thank you for the enlightenment. I need to go bust open a can of Pringles now.

Question... are the tires made out of recycled bazooka Gum ? That's what is being posted on the corvette forums....

 

[kratedisease]

potatoes....


I say the best way to serve them is whipped into mashed , Boston Market style....

 

[Hemotoxic]

Quick note to set the record straight on this.

In the industry "Carbon Fiber" is almost always an interchangeable term with "CFRP" (Carbon Fiber Reinforced Plastic or Polymer). It is indeed the same thing. Also sometimes refered to as "graphite", carbon fiber in its raw form is very strong in tension (like pulling on a rope) but is very week in compression (like pushing on a rope). CFRP takes the raw dry fiber and makes it strong in compression. The Viper uses some of the highest quality pre-preg carbon fiber available. We use various types of pre-preg carbon fiber depending on the area of the part. Woven carbon fiber is used on the inner panel to distribute the material properties and for a nice decorative finish. Unidirectional fiber is used on the outer skin because it will not 'read-out' the pattern like the weave will. Aerospace does the same thing. Sometimes carbon is woven, and sometimes it is countinuous or uni-directional.

Just want to put a stop to any rumors that your Gen-V Vipers are not built with the genuine carbon fiber!!

THANK YOU for elevating the signal-to-noise ratio here.

Then again, those who didn't understand this before are unlikely to change. "Waiter, I distinctly recall asking for table salt, but all you brought me was sodium chloride!"