New Fiberwerks rear spoiler
12-22-2006, 05:00 PM
#76
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Originally Posted by pete95zhn
Guessimating it's a 996 GT2 wing with custom mounts... Swedish car at Nürburgring. Post this pic to 951 board, some Swede over ther will tell you more about it, I think.
BTW, IMHO that's the only alternative to original spoiler. I don't like 968 TRS one at all.
BTW, IMHO that's the only alternative to original spoiler. I don't like 968 TRS one at all.
I was in JUNGSKILLE in 2005, btw, nice place.
12-22-2006, 05:01 PM
#77
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Originally Posted by Rich Sandor
There are various part numbers for the euro style rear bumper: 477(924), 944, and 951 part numbers. They are all different.
The thick rubber strip on the 951/S2 is, as far as I know, NLA (no longer available!!!) I might be wrong on that one, but that is what I've been told by various dealers in the UK.
I have a red 951/S2 euro-bumper in my basement, complete with rubber strip and the correct euro mounts as well. small repairable crack on one corner. I'll sell it for $1k.
GT racing / AIR make fibreglass replicas. The OEM euro bumoper is fibreglass as well, but it's pretty heavy. It's strongly reinforced I guess.
That swedish rear wing is almost definately a 996 GT2 wing, on custom mounts. I'd love to fab up something like that... but it's missing the bottom half of the wing, which mounts to the hatch..
The thick rubber strip on the 951/S2 is, as far as I know, NLA (no longer available!!!) I might be wrong on that one, but that is what I've been told by various dealers in the UK.
I have a red 951/S2 euro-bumper in my basement, complete with rubber strip and the correct euro mounts as well. small repairable crack on one corner. I'll sell it for $1k.
GT racing / AIR make fibreglass replicas. The OEM euro bumoper is fibreglass as well, but it's pretty heavy. It's strongly reinforced I guess.
That swedish rear wing is almost definately a 996 GT2 wing, on custom mounts. I'd love to fab up something like that... but it's missing the bottom half of the wing, which mounts to the hatch..
12-22-2006, 05:17 PM
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Originally Posted by Rich Sandor
But it's less effective and creates more drag.
the whole point of a wing is to create more drag (down force to hold the rear tires on the ground for more traction).
I think that not having the lower piece will create LESS drag over the hatch and the big wing will provide more down force and also keep the car in line because of the side bends on the wing (make the car easier to handle at high speeds), this is just a guess I made by thinking about how the air will flow over it.
never having raced in my life I would imagine that the goal is to optimize the relationship between downforce and drag coeficient so you get the best of both worlds or meet the goals you've set... i.e. drag racers dont want a big wing if they can keep their car on the ground without it.
12-22-2006, 05:46 PM
#80
Nordschleife Master
the whole point of a wing is to create more drag (down force to hold the rear tires on the ground for more traction).
DRAG DOES NOT CREATE LIFT/DOWNFORCE.
Drag is a RESULT of lift/downforce.
Drag is also a result of any shape that creates turbulent airflow.
Drag does not create downforce. It does not put extra weight on the rear wheels!!!
Additionally, you must understand the fundamental difference between a SPOILER and a WING. They are two different aerodynamic devices.
A SPOILER (like a 911 ducktail, or a 944 rubber spoiler) prevents the airflow along the roof from continueing downwards and propagating LIFT on the rear of the car. Note: A "Spoiler" DOES NOT CREATE Downforce, it ONLY "spoils" Lift.. and that's all. No Downforce, just an elimination of LIFT.
A WING, (inverted, on a racecar) on the other hand, actually re-directs air UPWARDS to create DOWNFORCE. Big difference! Both spoilers and wings create drag, of course, but they create drag in different ways. Drag created as a result of lift is called INDUCED drag. Induced drag increases at the square of your speed!!! (big drag) A spoiler, on the other hand, creates "parasite drag" which increases at a slower rate.
A racecar wing is also more dynamic.. it can be designed to create downforce from 60-100mph, and then "stall" above 100mph in order to reduce drag and allow a higher top speed!!!
Of course, you are right about balancing Drag/Downforce vs Top speed, but in general, sports cars will run small circuits with as much downforce as mechanically possible, whereas extremely light protoypes or openwheelers which can reach topspeed very fast, are the ones that have to worry about too much downforce for a circuit...
12-22-2006, 06:04 PM
#81
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Rich. A question for you. Can the large side pieces on many wings cause any detriment in cross winds or are they just a way to funnel more air past the wing?
12-22-2006, 06:07 PM
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Originally Posted by Rich Sandor
Ahh I KNEW you would make that misguided statement!!!
DRAG DOES NOT CREATE LIFT/DOWNFORCE.
Drag is a RESULT of lift/downforce.
Drag is also a result of any shape that creates turbulent airflow.
Drag does not create downforce. It does not put extra weight on the rear wheels!!!
Additionally, you must understand the fundamental difference between a SPOILER and a WING. They are two different aerodynamic devices.
A SPOILER (like a 911 ducktail, or a 944 rubber spoiler) prevents the airflow along the roof from continueing downwards and propagating LIFT on the rear of the car. Note: A "Spoiler" DOES NOT CREATE Downforce, it ONLY "spoils" Lift.. and that's all. No Downforce, just an elimination of LIFT.
A WING, (inverted, on a racecar) on the other hand, actually re-directs air UPWARDS to create DOWNFORCE. Big difference! Both spoilers and wings create drag, of course, but they create drag in different ways. Drag created as a result of lift is called INDUCED drag. Induced drag increases at the square of your speed!!! (big drag) A spoiler, on the other hand, creates "parasite drag" which increases at a slower rate.
A racecar wing is also more dynamic.. it can be designed to create downforce from 60-100mph, and then "stall" above 100mph in order to reduce drag and allow a higher top speed!!!
Of course, you are right about balancing Drag/Downforce vs Top speed, but in general, sports cars will run small circuits with as much downforce as mechanically possible, whereas extremely light protoypes or openwheelers which can reach topspeed very fast, are the ones that have to worry about too much downforce for a circuit...
DRAG DOES NOT CREATE LIFT/DOWNFORCE.
Drag is a RESULT of lift/downforce.
Drag is also a result of any shape that creates turbulent airflow.
Drag does not create downforce. It does not put extra weight on the rear wheels!!!
Additionally, you must understand the fundamental difference between a SPOILER and a WING. They are two different aerodynamic devices.
A SPOILER (like a 911 ducktail, or a 944 rubber spoiler) prevents the airflow along the roof from continueing downwards and propagating LIFT on the rear of the car. Note: A "Spoiler" DOES NOT CREATE Downforce, it ONLY "spoils" Lift.. and that's all. No Downforce, just an elimination of LIFT.
A WING, (inverted, on a racecar) on the other hand, actually re-directs air UPWARDS to create DOWNFORCE. Big difference! Both spoilers and wings create drag, of course, but they create drag in different ways. Drag created as a result of lift is called INDUCED drag. Induced drag increases at the square of your speed!!! (big drag) A spoiler, on the other hand, creates "parasite drag" which increases at a slower rate.
A racecar wing is also more dynamic.. it can be designed to create downforce from 60-100mph, and then "stall" above 100mph in order to reduce drag and allow a higher top speed!!!
Of course, you are right about balancing Drag/Downforce vs Top speed, but in general, sports cars will run small circuits with as much downforce as mechanically possible, whereas extremely light protoypes or openwheelers which can reach topspeed very fast, are the ones that have to worry about too much downforce for a circuit...
HOW TO GET MORE DOWNWARD PRESSURE
something sticking in the air that blocks airpassage will create a downward pressure related to the speed of air passing over it, so you get a downforce by putting a peice of rubber on the back of the car like the standard 944 wing... I've really felt the back of my 944 go down at high speeds.
HOW TO GET LESS DOWNWARD PRESSURE
now if you remove that peice of rubber then air passes on easily and creates no or LESS downforce pressure (this is where you said there was MORE drag by removing the lower peice of the wing - maybe we are talking about a different lower peice, I'm talking about the peice that goes where the standard 944 rubber spoiler goes)
HOW TO GET EITHER
now you add a wing on top and it can make the car lift or exert downard pressure by the shape and angle of the wing and can make it work at different speeds too like you said
MORE SIDE TO SIDE STABILITY
by bending the sides of the wing downward or upward to create vertical wings
12-22-2006, 06:13 PM
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Originally Posted by Rich Sandor
Ahh I KNEW you would make that misguided statement!!!
DRAG DOES NOT CREATE LIFT/DOWNFORCE.
Drag is a RESULT of lift/downforce.
DRAG DOES NOT CREATE LIFT/DOWNFORCE.
Drag is a RESULT of lift/downforce.
LIFT = UP = PULLING UP = UPWARD PRESSURE = UPWARD FORCE = UPFORCE
DRAG = DOWN = DOWNFORCE = DOWNWARD PRESSURE = FORCE IN THE OPPOSITE DIRECTION AS THE ACCELERATION, CHANGES FROM 180deg to 90deg as the car slows
SPOILER = just a word that people use to mean lots of things anything that has to do with air passing over is a spoiler
WING = like on an airplane, must have air space under and above it
LIFT does not equal downforce in my vocabulary
12-22-2006, 06:23 PM
#84
Nordschleife Master
LIFT = UP = PULLING UP = UPWARD PRESSURE = UPWARD FORCE = UPFORCE
DRAG = DOWN = DOWNFORCE = DOWNWARD PRESSURE = FORCE IN THE OPPOSITE DIRECTION AS THE ACCELERATION, CHANGES FROM 180deg to 90deg as the car slows
Memorise this diagram, it applies 100% to racecars, - INCLUDING the lift vector!!!
SPOILER = just a word that people use to mean lots of things anything that has to do with air passing over is a spoiler
12-22-2006, 06:34 PM
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drag and lift are really the same force, created by air flowing over something (they only differ in the direction of the vector.)
whereas, thrust is due to the engine power and weight is due to the mass and the earth's gravity
drag and lift are defined by "the Bernoulli Principle" that states that as the speed of a moving fluid increases, the pressure within the fluid decreases.
http://en.wikipedia.org/wiki/Bernoulli%27s_principle
whereas, thrust is due to the engine power and weight is due to the mass and the earth's gravity
drag and lift are defined by "the Bernoulli Principle" that states that as the speed of a moving fluid increases, the pressure within the fluid decreases.
http://en.wikipedia.org/wiki/Bernoulli%27s_principle
http://www.mrfizzix.com/carracing/bernoulli.htm
Bernoulli & Drag
The principles that allow an aircraft to fly are present in car racing. The difference being the wing or airfoil shape is mounted upside down producing down force instead of lift. The Bernoulli Effect means that "if a fluid (gas or liquid) flows around an object at different speeds, the slower moving fluid will exert more pressure than the faster moving fluid on the object. The object will then be forced toward the faster moving fluid.". The shape of the chassis on a race car is similar to an upside down airfoil. The air moving under the car moves faster than the air above it, creating down force or negative lift on the car. Airfoils or wings are also used in the front and rear of the car to generate more down force. Down force is necessary in maintaining high speeds through the corners and forces the car to the track. The shape of an underbody creates an area of low pressure between the bottom of the car and the surface of the track, which helps the car grip to the road resulting in higher cornering speeds.
Teams use track testing and wind tunnels to develop the most efficient aerodynamic design. The focus is on the aerodynamic forces of negative lift and drag. The relationship between drag and down force, or the negative lift, is especially important. Aerodynamic improvements in wings are directed at generating down force on the race car with a minimum of drag. Down force is important and necessary for the maintenance of speed through corners, unwanted drag will only slow the car. The most efficient design of a chassis is based on a down force/drag ratio.
A course with low speed corners, requires a car with a setup of high down force. A high down force package is necessary to reduce wear on the brakes and to maintain speeds. This includes large front and rear wings. The front wings have additional flaps that are adjustable. The rear wing is made of three sections that help maximize down force.
The setup for speedway looks much different. The front and rear wings are almost flat and used as stabilizers. The major down force in speedway cars are found in the shape of the over all body and underbody. Drag reduction is more critical on the speedway than on any other circuit. Since the drag force is proportional to the square of the speed, minimizing drag is a primary concern. Lap speeds can average over 228 mph and top speeds can exceed 240 mph on a speedway circuit. Effective use of down force is especially pronounced in high speed corners. A race car traveling at 200 mph. can produce down force that is approximately twice its weight.
Bernoulli & Drag
The principles that allow an aircraft to fly are present in car racing. The difference being the wing or airfoil shape is mounted upside down producing down force instead of lift. The Bernoulli Effect means that "if a fluid (gas or liquid) flows around an object at different speeds, the slower moving fluid will exert more pressure than the faster moving fluid on the object. The object will then be forced toward the faster moving fluid.". The shape of the chassis on a race car is similar to an upside down airfoil. The air moving under the car moves faster than the air above it, creating down force or negative lift on the car. Airfoils or wings are also used in the front and rear of the car to generate more down force. Down force is necessary in maintaining high speeds through the corners and forces the car to the track. The shape of an underbody creates an area of low pressure between the bottom of the car and the surface of the track, which helps the car grip to the road resulting in higher cornering speeds.
Teams use track testing and wind tunnels to develop the most efficient aerodynamic design. The focus is on the aerodynamic forces of negative lift and drag. The relationship between drag and down force, or the negative lift, is especially important. Aerodynamic improvements in wings are directed at generating down force on the race car with a minimum of drag. Down force is important and necessary for the maintenance of speed through corners, unwanted drag will only slow the car. The most efficient design of a chassis is based on a down force/drag ratio.
A course with low speed corners, requires a car with a setup of high down force. A high down force package is necessary to reduce wear on the brakes and to maintain speeds. This includes large front and rear wings. The front wings have additional flaps that are adjustable. The rear wing is made of three sections that help maximize down force.
The setup for speedway looks much different. The front and rear wings are almost flat and used as stabilizers. The major down force in speedway cars are found in the shape of the over all body and underbody. Drag reduction is more critical on the speedway than on any other circuit. Since the drag force is proportional to the square of the speed, minimizing drag is a primary concern. Lap speeds can average over 228 mph and top speeds can exceed 240 mph on a speedway circuit. Effective use of down force is especially pronounced in high speed corners. A race car traveling at 200 mph. can produce down force that is approximately twice its weight.
12-22-2006, 06:42 PM
#86
Nordschleife Master
Drag does not act opposite to upforce/downforce. Drag acts opposite to THRUST.
Think about it.. weight is what pulls your car down. Downforce from a wing acts together with weight (in the same downward direction.)
Drag (form drag, parasite drag, or induced drag) may be created by lift/downforce, but it acts opposed to thrust, not lift/downforce.
Think about it.. weight is what pulls your car down. Downforce from a wing acts together with weight (in the same downward direction.)
Drag (form drag, parasite drag, or induced drag) may be created by lift/downforce, but it acts opposed to thrust, not lift/downforce.
12-22-2006, 06:42 PM
#87
Nordschleife Master
drag and lift are really the same force, created by air flowing over something (they only differ in the direction of the vector.)
12-22-2006, 06:56 PM
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this is all a semantical argument over words, but from a text book and theory aspect
you even agree with me, you just use different words
at the most simple level the only variables that exist in the equation are:
1) force forward (you call it thrust)
2) force backward (you call it drag)
3) force down (mass x acceleration of gravity) + the vector of force downward cause by the air flow (you call it downforce - I call it drag in the downward direction)
however if you go down a hill or into a nose dive the word you use "thrust" is no longer descriptive since the force forward is no longer provided by the engine only so its better to use non "industry" slang words and speak in terms of pure generic descriptive words that don't need to be defined, i.e. force backwards (everyone knows what that means)
(of course there are more variables like temperature of the air, volume of air, but we can factor them out if we are only talking about all cars being at the same place and time under the same conditions)
a simple example of the fact that drag and lift are the same thing is that of a movable wing that can be moved from 10deg below level where it produces a lift to 90 degrees where it acts like an air brake and produces a drag and a downforce - both are the same force, which is the force of a fluid over a body (Bernoulli principle) but just felt in a different direction. i.e. one is felt as a lift the other is felt as a weight down and back.
you even agree with me, you just use different words
at the most simple level the only variables that exist in the equation are:
1) force forward (you call it thrust)
2) force backward (you call it drag)
3) force down (mass x acceleration of gravity) + the vector of force downward cause by the air flow (you call it downforce - I call it drag in the downward direction)
however if you go down a hill or into a nose dive the word you use "thrust" is no longer descriptive since the force forward is no longer provided by the engine only so its better to use non "industry" slang words and speak in terms of pure generic descriptive words that don't need to be defined, i.e. force backwards (everyone knows what that means)
(of course there are more variables like temperature of the air, volume of air, but we can factor them out if we are only talking about all cars being at the same place and time under the same conditions)
a simple example of the fact that drag and lift are the same thing is that of a movable wing that can be moved from 10deg below level where it produces a lift to 90 degrees where it acts like an air brake and produces a drag and a downforce - both are the same force, which is the force of a fluid over a body (Bernoulli principle) but just felt in a different direction. i.e. one is felt as a lift the other is felt as a weight down and back.
12-22-2006, 07:42 PM
#90
Nordschleife Master
this is all a semantical argument over words, but from a text book and theory aspect
you even agree with me, you just use different words
you even agree with me, you just use different words
at the most simple level the only variables that exist in the equation are:
1) force forward (you call it thrust)
2) force backward (you call it drag)
3) force down (mass x acceleration of gravity) + the vector of force downward cause by the air flow (you call it downforce - I call it drag in the downward direction)
1) force forward (you call it thrust)
2) force backward (you call it drag)
3) force down (mass x acceleration of gravity) + the vector of force downward cause by the air flow (you call it downforce - I call it drag in the downward direction)
however if you go down a hill or into a nose dive the word you use "thrust" is no longer descriptive since the force forward is no longer provided by the engine only so its better to use non "industry" slang words and speak in terms of pure generic descriptive words that don't need to be defined, i.e. force backwards (everyone knows what that means)
a simple example of the fact that drag and lift are the same thing is that of a movable wing that can be moved from 10deg below level where it produces a lift to 90 degrees where it acts like an air brake and produces a drag and a downforce - both are the same force, which is the force of a fluid over a body (Bernoulli principle) but just felt in a different direction. i.e. one is felt as a lift the other is felt as a weight down and back.
Imagine an airplane wing moving forward, from the side view, at a flat horizontal setting. Drag is acting directly rearwards: exactly opposite of thrust. If you increase the angle of the wing relative to the airflow (angle of attack) you increase the lift which that is generating. You also increase the Drag. Here is the trick.. you are NOT changing the DIRECTION of the Drag vector, you are only changing the INTENSITY of the Drag vector.
Do you understand?