Cool Formula for HP Needed

The formula is Speed (in MPH) cubed times Frontal Area (of the car in square feet) divided by 150,000.

 

For example, if the Murci has a frontal area of 12 sq. ft., to go 300MPH it would need 2160HP. I assume the formula means NET HP which, as you know, is even lower than wheel horsepower as it takes friction and rolling resistance into the equation.

 

Pretty cool! I would love to get the exact frontal area of the Murci. I think it would be very tough given the angles involved.

The formula is Speed (in MPH) cubed times Frontal Area (of the car in square feet) divided by 150,000.

 

For example, if the Murci has a frontal area of 12 sq. ft., to go 300MPH it would need 2160HP. I assume the formula means NET HP which, as you know, is even lower than wheel horsepower as it takes friction and rolling resistance into the equation.

 

Pretty cool! I would love to get the exact frontal area of the Murci. I think it would be very tough given the angles involved.

 

It's not so much difficult as it is time consuming. Take a front perspective and begin to cover the body in a color vinyl until the entire visible portion of the car is covered. The just see how much vinyl you used. That will be pretty exact.

 

However, I don't see how a formula like that can be accurate whatsoever. I don't see how you can relate solely speed, horsepower, air resistance, and surface area. Aerodynamics, air flow and weight most certainly play a role in this.

The frontal area isnt necessarily a vertical wall either. Im sure the air flows over it differently than if it were just a 12 sq. ft. wall, so would you have to also factor in the angles of all the surfaces as well?

The frontal area isnt necessarily a vertical wall either. Im sure the air flows over it differently than if it were just a 12 sq. ft. wall, so would you have to also factor in the angles of all the surfaces as well?

 

Thats exactly what i was thinking. The sloping back of the windshield wouldnt just be a 1ft tall rectangle of resistance but a say 45 degree slope with even less resistance.....

 

FLAWED! YOUR FORMULA IS FLAWED LIKE YOUR LOGIC DAVID!!!

It's just an approximation guys. The more accurate you want to be the messier it gets. You have to bring in the density of air, convert that to its molecular weight, include the drag coefficient for the vehicle, a bunch of conversions, run the numbers etc.

 

Remember air resistance increases exponentially as desired speed increases. It's why you use more fuel the faster you go. Wide tires slow you down, drive train power loss.....

 

 

Wiggs has a good approximation, thats much easier to do on the back of a napkin.

FLAWED! YOUR FORMULA IS FLAWED LIKE YOUR LOGIC DAVID!!!

 

 

:lol2:

The formula is Speed (in MPH) cubed times Frontal Area (of the car in square feet) divided by 150,000.

 

For example, if the Murci has a frontal area of 12 sq. ft., to go 300MPH it would need 2160HP. I assume the formula means NET HP which, as you know, is even lower than wheel horsepower as it takes friction and rolling resistance into the equation.

 

Pretty cool! I would love to get the exact frontal area of the Murci. I think it would be very tough given the angles involved.

 

That formula is missing a few things (coeffecient of drag and air density being the big ones).... I've never heard the term "net hp" before so I'm not too sure what you mean by that one, but I'm going to assume the result of the formula will give you required WHP.

 

There is a calculator at the bottom of this page that should be a little more accurate.

 

http://www.rbracing-rsr.com/aerohpcalc.html

Quite a bit more info is needed here Wiggs... But 21xx hp seems obscenely high for a Murci to crack 300mph, doing it in a given distance obviously requires substantially more power.

 

FYI, this firebird did 300 on the salt with ~1500 crank hp.

 

http://www.mitechengines.com/picture%20gal...es%20page-1.htm

 

 

Quite a bit more info is needed here Wiggs... But 21xx hp seems obscenely high for a Murci to crack 300mph, doing it in a given distance obviously requires substantially more power.

I don't know where Wiggs took 12 sqft from, but considering the Diablo has a frontal area of 6.24 sqft, the Murci should be about the same.

 

For the Diablo @ 300 mph:

 

((300^3) * 6,24) / 150 000 = 1123,2 HP, which is about 1500 crank hp.

Thats exactly what i was thinking. The sloping back of the windshield wouldnt just be a 1ft tall rectangle of resistance but a say 45 degree slope with even less resistance.....

 

FLAWED! YOUR FORMULA IS FLAWED LIKE YOUR LOGIC DAVID!!!

 

 

I said exactly that! I didn't know how to figure out the area given the angles!

 

And I was guessing with 12 sq. ft. I have no clue what it actually is. It's the frontal area of the bumper plus some percentage of the rest of the front of the car (given its angles).

Okay, pay attention at the back... the "slipperyness" is calculated cd which drag co-efficiency, the higher the number the worse it is.

 

Not the most up-to-date website but some base data to use

 

http://www.mayfco.com/lambor.htm

 

Some graphs from the same site http://www.mayfco.com/tbls.htm

 

A LP640 is 0.33. Earlier murcie models will be different because of how the air will flow over the bumper.

Once the intakes come up the efficiency increases to 0.36. Now as we all know children that the scoops need to come up to feed the motor so any calculations for top speed will need to include that.

 

Now other to the supernerds that have yet to touch a real actual woman's breast, NASA.

 

http://www.grc.nasa.gov/WWW/K-12/airplane/dragco.html

 

&

 

http://wright.nasa.gov/airplane/drageq.html

 

So using those formulas we can deduce that I will be fucked if I am working it out for you.

Okay, pay attention at the back... the "slipperyness" is calculated cd which drag co-efficiency, the higher the number the worse it is.

 

Not the most up-to-date website but some base data to use

 

http://www.mayfco.com/lambor.htm

 

Some graphs from the same site http://www.mayfco.com/tbls.htm

 

A LP640 is 0.33. Earlier murcie models will be different because of how the air will flow over the bumper.

Once the intakes come up the efficiency increases to 0.36. Now as we all know children that the scoops need to come up to feed the motor so any calculations for top speed will need to include that.

 

Now other to the supernerds that have yet to touch a real actual woman's breast, NASA.

 

http://www.grc.nasa.gov/WWW/K-12/airplane/dragco.html

 

&

 

http://wright.nasa.gov/airplane/drageq.html

 

So using those formulas we can deduce that I will be fucked if I am working it out for you.

 

 

Teach, you are wrong. The scoops retract at 150MPH no matter what the ambient or internal conditions are so they never ened to be factored in for top speed calculations.

 

Teach, you are wrong. The scoops retract at 150MPH no matter what the ambient or internal conditions are so they never ened to be factored in for top speed calculations.

 

 

Pipe down Wiggs, I am still waiting for you to hand me your homework from last week.

 

Plus you would have to factor in some devices to prevent lift at that speed.

Pipe down Wiggs, I am still waiting for you to hand me your homework from last week.

 

Plus you would have to factor in some devices to prevent lift at that speed.

 

 

But teach, I told you, my Danes ate it!

 

And don't deflect about being wrong! No one likes a sore professor!

<---------From the back...

 

Teach, you are wrong. The scoops retract at 150MPH no matter what the ambient or internal conditions are so they never ened to be factored in for top speed calculations.

 

I was going to point that out but you beat me to it!

But teach, I told you, my Danes ate it!

 

And don't deflect about being wrong! No one likes a sore professor!

 

 

Jesus say one thing wrong and someone tries to rape you infront of the class.

 

Detection Wiggs, see me after school.

 

 

PS I am still maintain that any anti-lift devices would offer similar resistance to that of the scoops.

Jesus say one thing wrong and someone tries to rape you infront of the class.

 

Detection Wiggs, see me after school.

 

 

PS I am still maintain that any anti-lift devices would offer similar resistance to that of the scoops.

 

 

Welcome to U.S. public schools!! !!!!