Top Speed???
July-17th-2003, 10:27 AM
#31
Protegé Master
Join Date: Sep 2002
Location: Montreal, Canada
Posts: 194
Originally posted by Davard
Do you really think that a Protege is anywhere near its terminal velocity at 120mph????
Drag increases with the cube of speed, and horsepower (or thrust) is usually the limiting factor in top speed. Design considerations and structural limits (both heat and drag/friction forces) are bigger limiters of top speed than power. Who would think you could make a semi, with a drag coefficient greater than a brick, go 300mph, but stick enough HP behind it (in th eform of three jet engines), and it's possible. Not sane, but possible.
From the dictionary definition of terminal velocity:
The constant velocity of a falling body, attained when the resistance of air, water, or other surrounding fluid has become equal to the force of gravity acting on the body.
or from http://scienceworld.wolfram.com/physics/Projectile.html
A projectile is a body which is propelled (or thrown) with some initial velocity, and then allowed to be acted upon by the forces of gravity and possible drag. The maximum upward distance h reached by the projectile is called the height, the horizontal distance traveled x the range (or sometimes distance), and the path of the object is called its trajectory. If a body is allowed to free-fall under gravity and is acted upon by the drag of air resistance, it reaches a maximum downward velocity known as the terminal velocity. The study of the motion of projectiles is called ballistics.
Do you really think that a Protege is anywhere near its terminal velocity at 120mph????
Drag increases with the cube of speed, and horsepower (or thrust) is usually the limiting factor in top speed. Design considerations and structural limits (both heat and drag/friction forces) are bigger limiters of top speed than power. Who would think you could make a semi, with a drag coefficient greater than a brick, go 300mph, but stick enough HP behind it (in th eform of three jet engines), and it's possible. Not sane, but possible.
From the dictionary definition of terminal velocity:
The constant velocity of a falling body, attained when the resistance of air, water, or other surrounding fluid has become equal to the force of gravity acting on the body.
or from http://scienceworld.wolfram.com/physics/Projectile.html
A projectile is a body which is propelled (or thrown) with some initial velocity, and then allowed to be acted upon by the forces of gravity and possible drag. The maximum upward distance h reached by the projectile is called the height, the horizontal distance traveled x the range (or sometimes distance), and the path of the object is called its trajectory. If a body is allowed to free-fall under gravity and is acted upon by the drag of air resistance, it reaches a maximum downward velocity known as the terminal velocity. The study of the motion of projectiles is called ballistics.
When you found those definitions, did you Google "terminal velocity free fall"??? Because that would definitely result in the biased definitions you listed above. Here's something I found when I Googled the words "terminal velocity":
Terminal velocity, noun:
1: the constant maximum velocity reached by a body falling under gravity through a fluid, esp. the atmosphere
2: the velocity of a missile or projectile when it reaches its target
3: the maximum velocity attained by a rocket, missile, or shell flying in a parabolic flight path
4: the maximum velocity that an aircraft can attain, as determined by its total drag
Read number 4! Stick that in your pipe and smoke it! And please don't make me bust out my Engineering physics text books cuz they're packed away in boxes ever since I graduated!
July-17th-2003, 11:01 AM
#33
Recreational Gynocolist
Join Date: Jul 2002
Location: Tallahassee, FL
Posts: 568
Originally posted by damaster
Terminal velocity, noun:
1: the constant maximum velocity reached by a body falling under gravity through a fluid, esp. the atmosphere
2: the velocity of a missile or projectile when it reaches its target
3: the maximum velocity attained by a rocket, missile, or shell flying in a parabolic flight path
4: the maximum velocity that an aircraft can attain, as determined by its total drag
Read number 4! Stick that in your pipe and smoke it! And please don't make me bust out my Engineering physics text books cuz they're packed away in boxes ever since I graduated!
Terminal velocity, noun:
1: the constant maximum velocity reached by a body falling under gravity through a fluid, esp. the atmosphere
2: the velocity of a missile or projectile when it reaches its target
3: the maximum velocity attained by a rocket, missile, or shell flying in a parabolic flight path
4: the maximum velocity that an aircraft can attain, as determined by its total drag
Read number 4! Stick that in your pipe and smoke it! And please don't make me bust out my Engineering physics text books cuz they're packed away in boxes ever since I graduated!
just curious, wouldn't all 4 be considered falling objects? Take number 4 for example, it isn't necesarilly free falling but it is falling. It's just that lift = gravity.
July-17th-2003, 02:39 PM
#34
2002 RX-7 Spirit 'R'
Join Date: Jul 2002
Location: Brampton, Ontario, Canada
Posts: 872
even though i was taught the same thing as damaster
i know that the protege hasn't hit its terminal velocity,
at our current setups we are definately drag limited
but i styll do believe that there is a terminal velocity speed for our proteges, but its a lot higher up
i know that the protege hasn't hit its terminal velocity,
at our current setups we are definately drag limited
but i styll do believe that there is a terminal velocity speed for our proteges, but its a lot higher up
July-17th-2003, 02:56 PM
#35
Protegé Master
Join Date: Sep 2002
Location: Montreal, Canada
Posts: 194
Originally posted by PseudoRealityX
So, in conclusion...
1) You aren't "damaster" of aerodynamic principles
2) The protege is not at "terminal velocity"
3) more power in the right place to the wheels WILL infact increase the top speed of the vehicle
So, in conclusion...
1) You aren't "damaster" of aerodynamic principles
2) The protege is not at "terminal velocity"
3) more power in the right place to the wheels WILL infact increase the top speed of the vehicle
I'll say it again and again: terminal velocity applies to BOTH free falling objects and moving objects (take motion physics and you'll learn a thing or two)! Got any references from your textbooks Vagabond since its fresh in your mind?concerning (2), I never mentioned that anyone has attained terminal velocity with their Proteges, so I don't know where the heck you're getting that from: read the thread! toucci said any perfomance increase will boost the top speed which I replied to by saying "not necessarily" because at some point you'll hit terminal velocity and no matter how much forward force you add, it won't do ****! I never said 203 km/h was my car's terminal velocity, I said that was the most I had hit and I don't think anybody here has achieved the Protege's terminal velocity because our cars don't have enough power to make it to terminal velocity.
3): i've answered that in (2)
July-17th-2003, 03:34 PM
#37
Protegé Master
Join Date: Sep 2002
Location: Montreal, Canada
Posts: 194
Originally posted by PseudoRealityX
and you're wrong, still
http://www.grc.nasa.gov/WWW/K-12/airplane/termv.html
As long as you can add enough force to the wheels, you will ALWAYS increase theoretical top speed. There are aerodynamic "walls", but with enough power, and a structure built to stand them, you CAN surpass them.
It also depends on the altitude, barometric pressure, surface....etc etc etc.
The term "terminal velocity" is USUALLY slated for objects in free fall.
Here's the part you keep missing. In free fall, where terminal velocity is usually applied, the "thrust" of the falling object never increases. So by your defintion, the Protege at top speed "is" at it's terminal velocity of a 130 crank hp Protege.
Read my whole previous post again, where you get into the free fall and WHY thrust doesn't increase something falls.
However, that's NOT the top speed it can reach given more power.
and you're wrong, still
http://www.grc.nasa.gov/WWW/K-12/airplane/termv.html
As long as you can add enough force to the wheels, you will ALWAYS increase theoretical top speed. There are aerodynamic "walls", but with enough power, and a structure built to stand them, you CAN surpass them.
It also depends on the altitude, barometric pressure, surface....etc etc etc.
The term "terminal velocity" is USUALLY slated for objects in free fall.
Here's the part you keep missing. In free fall, where terminal velocity is usually applied, the "thrust" of the falling object never increases. So by your defintion, the Protege at top speed "is" at it's terminal velocity of a 130 crank hp Protege.
Read my whole previous post again, where you get into the free fall and WHY thrust doesn't increase something falls.
However, that's NOT the top speed it can reach given more power.
Read up on Reynolds Number (Fdrag = bv^n, where n is the Reynolds Number which is different for every object) and how drag force is not directly proportional to the velocity of an object. Not to mention that as the faster you go, forces of kinetic friction increase as well. Drag (which is not directly proportional to the velocity) + kinetic friction + other forces (in the REAL, non-theoretical world, there is still also static friction even though you're moving which adds to the kinetic friction) will lead to terminal velocity.
In your post you say "As long as you can add enough force to the wheels, you will ALWAYS increase theoretical top speed". I say, get the heck out of your "theoretical" world and get REAL! Think about drag (not linearly proportional to velocity), kinetic friction, mass added to increase the force, etc., etc., etc.!!!
So no, I'm not wrong!
and I think we've gone very much off-topic on this thread...
July-18th-2003, 01:11 AM
#38
Protege Newbie
Join Date: Jul 2003
Location: Gainesville, FL
Posts: 1
Damaster, you're kidding right? They seriously teach engineering like that up in Canada????
First off, coefficient of drag is largely determined by geometry, and once you are in the fully turbulent region(which a fast moving protege or aircraft is). In the low speed region Cd changes with reynolds number, which is a function of velocity and geometry.
So next, the definition of Cd from"Fluid Mechanics" by Frank M. White Drag force = 1/2 * Cd * rho * Vel^2 * frontal area
It's very well known that up until Mach 0.3 you can consider the flow incompressible and this equation holds true, so up until about 210 mph drag force goes up with the square of velocity.
After that it goes up a bit quicker, it takes a fair chunk of power to go over Mach 1, however, if you add power there are one of three things that must happen
1) It will go faster
2) It will blow up
3) it will be traction/gear limited
In the case of an airplane, they have a maximum speed at which they have a chance of ripping the wings off, which no one wants, but if you add power to an airplane, it will get faster, period...
where the hell did you get that equation for drag force where you are it's velocity to the power of the reynolds number???? are you kidding? Drag deviates from the square function at high speeds but it would never approach an exponential relation to velocity, that's ridiculous.
Did you really take engineering classes or just send $50 in the mail and get a certificate, I'm dead serious, it honestly scares me for someone to have an engineering degree and think that, down here an engineering degree means something. Mainly that I learned something.
I may be reading between the lines, maybe you don't have an engineering degree and just took a physics class like half the people at my school, but if you do, are you serious???
If that's how you engineer stuff, I'm glad you don't make the airplanes I ride or the cars I drive.
First off, coefficient of drag is largely determined by geometry, and once you are in the fully turbulent region(which a fast moving protege or aircraft is). In the low speed region Cd changes with reynolds number, which is a function of velocity and geometry.
So next, the definition of Cd from"Fluid Mechanics" by Frank M. White Drag force = 1/2 * Cd * rho * Vel^2 * frontal area
It's very well known that up until Mach 0.3 you can consider the flow incompressible and this equation holds true, so up until about 210 mph drag force goes up with the square of velocity.
After that it goes up a bit quicker, it takes a fair chunk of power to go over Mach 1, however, if you add power there are one of three things that must happen
1) It will go faster
2) It will blow up
3) it will be traction/gear limited
In the case of an airplane, they have a maximum speed at which they have a chance of ripping the wings off, which no one wants, but if you add power to an airplane, it will get faster, period...
where the hell did you get that equation for drag force where you are it's velocity to the power of the reynolds number???? are you kidding? Drag deviates from the square function at high speeds but it would never approach an exponential relation to velocity, that's ridiculous.
Did you really take engineering classes or just send $50 in the mail and get a certificate, I'm dead serious, it honestly scares me for someone to have an engineering degree and think that, down here an engineering degree means something. Mainly that I learned something.
I may be reading between the lines, maybe you don't have an engineering degree and just took a physics class like half the people at my school, but if you do, are you serious???
If that's how you engineer stuff, I'm glad you don't make the airplanes I ride or the cars I drive.
August-15th-2003, 04:50 PM
#40
Protegé Master
Join Date: Sep 2002
Location: Montreal, Canada
Posts: 194
Jreyenga, unlike you, I'm not a pocket-protector-clad physics nerd, so I won't argue the matter further. On my way to achieving my Engineering degree, I did 4 basic physics courses, and that's where I learned the definition of the term terminal velocity that I stated earlier. You got beef with it, take it up with the author of my text book and my professor!
And, just in case you don't know, Software/Computer Engineers don't design the cars you drive or the airplanes you ride, dumbass! But I do design the tools you are using as you read this! Mu hu ha ha ha ha ha ha!
And, just in case you don't know, Software/Computer Engineers don't design the cars you drive or the airplanes you ride, dumbass! But I do design the tools you are using as you read this! Mu hu ha ha ha ha ha ha!
August-15th-2003, 08:36 PM
#41
YEAH WOW CHILDISH!
Join Date: Jul 2002
Location: under your bed
Posts: 1,727
HMMMMMMMMMM my 1999 1.6 litre was governed at 115, as soon as i hit 115 it cut fuel, felt like i hit a brick wall. then as soon as it dipped below 115 it kicked back in. im sure its like this for all 1.6 litres, i dont believe mazda would limit some, and not others. im sure its a standard thing they do.
August-16th-2003, 12:56 AM
#42
Use this to install stuff
Join Date: Mar 2002
Location: State College, PA
Posts: 1,069
Speed limiters are usually used for the OE tire ratings, and if the stock drag limited speed is higher than the tires rating a limiter is used to reduce the speed under that of the tires...Not all proteges have them...
August-18th-2003, 11:56 AM
#44
Certified Sick Individual
Join Date: Mar 2002
Location: Houston, TX.
Posts: 1,141
Funny stuff here. This is what I remember from Physics (hazy memory at that, and I do not profess to be an expert on this):
A. Maximum speed any object can obtain (without getting into wormholes and ****) is somewhere south of the speed of light.
B. That is because the object will eventually reach a speed where all the energy in the universe cannot increase its speed.
C. With drag forces acting on it, that maximum will be quite a bit slower.
D. If you ignore the constraints of available energy in the universe then you could make an object go light speed.
And basically whole point being, there is no way in hell that a Protege is going to reach a speed anywhere near it's theoretical maximum with a human inside. It would destroy itself before it got anywhere near. So the whole ****** bickering conversation was pretty much pointless.
BTW... I have been up to 120, and it had some pull left. Maybe someday I will find a road a bit longer to stretch the legs on.
A. Maximum speed any object can obtain (without getting into wormholes and ****) is somewhere south of the speed of light.
B. That is because the object will eventually reach a speed where all the energy in the universe cannot increase its speed.
C. With drag forces acting on it, that maximum will be quite a bit slower.
D. If you ignore the constraints of available energy in the universe then you could make an object go light speed.
And basically whole point being, there is no way in hell that a Protege is going to reach a speed anywhere near it's theoretical maximum with a human inside. It would destroy itself before it got anywhere near. So the whole ****** bickering conversation was pretty much pointless.
BTW... I have been up to 120, and it had some pull left. Maybe someday I will find a road a bit longer to stretch the legs on.
August-20th-2003, 12:52 PM
#45
Thread Killa'
Join Date: Jul 2002
Location: k-town, USA
Posts: 326
Originally posted by kc5zom
And basically whole point being, there is no way in hell that a Protege is going to reach a speed anywhere near it's theoretical maximum with a human inside. It would destroy itself before it got anywhere near. So the whole ****** bickering conversation was pretty much pointless.
And basically whole point being, there is no way in hell that a Protege is going to reach a speed anywhere near it's theoretical maximum with a human inside. It would destroy itself before it got anywhere near. So the whole ****** bickering conversation was pretty much pointless.