Brand new at this please help !

[taper41]

I was just asking if power cubed and drag squared are equivalent and if they are wouldnt the same change to either have the same result

[4-barrel Mike]

Interesting!  I was just doing a little research using the fine search function of this site.   

taper:

Maybe these can help you a little:

http://www.landracing.com/forum/index.php/topic,826.msg7604.html#msg7604
http://www.landracing.com/forum/index.php/topic,3900.msg52487.html#msg52487

Mike

[salt27]

Mike,
Good find, that was exactly what I was thinking of.
It looks as if we are all cleared up now.

Thanks, Don

[taper41]

Ok, so thrust is what should be used instead of horsepower, but its still not answering my question, I gave your the statement of which Im trying to understand and the question which was if you change the power or the drag by the same percent would you get the same result or not, and no one has given me a straight answer.

[fastman614]

Fastman, here is my post that taper thought contradicted you. I don't think you'll argue with it.

if  you decrease the aerodynamic drag by 25% or add power by 25% would the result differ or be the same, if it was on the same vehicle?

Set unit values arbitrarily so power/drag ratio is 1.
Decrease drag by 25%, power/drag is 1/.75=1.33.
Increase power by 25%, power/drag is 1.25/1=1.25
Ergo, result differs, decreasing drag 25% gives superior result.

I think we've done all we can.

When dealing with engineers, there comes a time when engineers are best left to argue amongst themselves.... and we Maintenance/repair/installation technicians (who by trade designation, call ourselves millwrights) quietly go ahead and install or repair the item being argued about.... we then let the engineer(s), by process of elimination, figure out by what (or whose) method it was done... while we just stand back with a knowing smile .... knowing that the process will repeat and that the outcome(s) will be accomplished my much the same method the next time...

So, in Toronto, Ontario (Canada) the millwrights union local was incorporated in April of 1958. In 2008, they had stickers made for their hardhats that said something like - Millwrights Local 1454 - Incorporated April 15, 1958.... Making Engineers Look Good For Over 50 Years!

I don't profess a whole lot of real engineering expertise... I understand the math.... I can do A LOT of practical "on the job" engineering but with aerodynamics and how to make cars go fast, I know about 3 or 4 things....

1- Make sure that your car is built to "known" specifications (looking at other "fast" dragster type lakesters, I copied them)

Enhance the aerodynamics by what you see on any other fast cars. (With what I had to work with, I copied, to the best of my ability, the rear tail extension and top "fin" that Al Teague had on his streamliner - Al did not have a rear tail fin anywhere near as pronounced as most other fast cars)

3- "Buy" or otherwise procure as much horsepower as you can - even going in to debt to do so! (I bought a  "new" Dodge R5P7 engine that was massaged beyond NASCAR legality)

4- I chose a transmission with custom gear ratios that help keep the engine running within 7% of peak horsepower from the top of second gear on up...

It has resulted in record setting performance.... beyond this is guesswork on my part... and the farther away from these above that the guesswork takes place, the "less educated" of guesswork it is.

Like I inferred and perhaps said earlier, Taper41 - I wish you well in your schooling... I also hope you take a lesson or two from this exercise... If, for instance you compiled the more educated replies, made calculations and answers etc based on those replies and then asked for further input in the vent that you were not understanding the outcomes, you could have "ramped" the intellectual level of this thread up a bit.

I did also say that some of the information has already been filed away for my future reference. I will be working over what I have saved.... for this I am thankful as some of the replies and postings, while not fully understood by me, had information that I never knew and I will be attempting to make some practical application of it, if for no other reason than to make some meaningful "fudge" numbers in my desktop dyno program.

I believe that this discussion may never be "over" .... if Taper41 comes back on here and posts some interesting facts obtained via his studies, I for one will be interested in what he will have to say....

Wishing you all "happy posting"....
Dave

[jl222]

I know that some of these question i have might be elementary to you folks that are veterans at this but please help to inform me of some of the simple questions due to a study that i have been doing for physics....

in a perfect world where traction was not a problem, when trying to reach top end speeds, is it more advantageous to have the streamliner equipped with 4 wheels like a tradition car or 2 wheels like a tradition motorcycle, lets keep the wheels all at the same with for either vehicle for a controlled variable and say that both liners have the same weight and power along with same dimensions. theoretically wouldn't the motorcycle style have a lower drag thus  enabling it to reach higher speeds.

from the outside looking in i dont understand how the 4 wheel streamliners have been able to reach higher top speeds
wouldnt the 2 wheel design be more efficient for top speed

as silly as this might be i thank whomever helps me with this

  First it's a perfect world were traction is not a problem, then you refer to the current record speeds set on a track were distance and traction is a problem.

  Thats why 4 wheels and hp rule.

  Inputing and refining data in the Bville Pro program shows why.

           Starting data 1208 hp CD .300  gearing  2.3   mph after 1 mile 213   2 miles 245  3 miles 257  4 m 263  5 m 265

          -25% CD        1208 hp CD .225    ''        2.15   ''             ''    218       ''      253     ''       270   ''    280   ''  284

          +25% HP        1510 HP CD .300    ''        2.1    '''            ''     231       ''       263     ''      279    ''   285   ''  289

        At the finish the lower Cd is catching up but Bville Pro only goes 5 miles

       Also the program is optimistic on acceleration as it won't input the 4'' wide tires used by most.
       But we have been ahead of program inputs at El Mirage [which has better traction than Bville] with the 222 camaro


                    JL222   
 

[jl222]

Fastman, here is my post that taper thought contradicted you. I don't think you'll argue with it.

if  you decrease the aerodynamic drag by 25% or add power by 25% would the result differ or be the same, if it was on the same vehicle?

Set unit values arbitrarily so power/drag ratio is 1.
Decrease drag by 25%, power/drag is 1/.75=1.33.
Increase power by 25%, power/drag is 1.25/1=1.25
Ergo, result differs, decreasing drag 25% gives superior result.

I think we've done all we can.

When dealing with engineers, there comes a time when engineers are best left to argue amongst themselves.... and we Maintenance/repair/installation technicians (who by trade designation, call ourselves millwrights) quietly go ahead and install or repair the item being argued about.... we then let the engineer(s), by process of elimination, figure out by what (or whose) method it was done... while we just stand back with a knowing smile .... knowing that the process will repeat and that the outcome(s) will be accomplished my much the same method the next time...

So, in Toronto, Ontario (Canada) the millwrights union local was incorporated in April of 1958. In 2008, they had stickers made for their hardhats that said something like - Millwrights Local 1454 - Incorporated April 15, 1958.... Making Engineers Look Good For Over 50 Years!

I don't profess a whole lot of real engineering expertise... I understand the math.... I can do A LOT of practical "on the job" engineering but with aerodynamics and how to make cars go fast, I know about 3 or 4 things....

1- Make sure that your car is built to "known" specifications (looking at other "fast" dragster type lakesters, I copied them)

Enhance the aerodynamics by what you see on any other fast cars. (With what I had to work with, I copied, to the best of my ability, the rear tail extension and top "fin" that Al Teague had on his streamliner - Al did not have a rear tail fin anywhere near as pronounced as most other fast cars)

3- "Buy" or otherwise procure as much horsepower as you can - even going in to debt to do so! (I bought a  "new" Dodge R5P7 engine that was massaged beyond NASCAR legality)

4- I chose a transmission with custom gear ratios that help keep the engine running within 7% of peak horsepower from the top of second gear on up...

It has resulted in record setting performance.... beyond this is guesswork on my part... and the farther away from these above that the guesswork takes place, the "less educated" of guesswork it is.

Like I inferred and perhaps said earlier, Taper41 - I wish you well in your schooling... I also hope you take a lesson or two from this exercise... If, for instance you compiled the more educated replies, made calculations and answers etc based on those replies and then asked for further input in the vent that you were not understanding the outcomes, you could have "ramped" the intellectual level of this thread up a bit.

I did also say that some of the information has already been filed away for my future reference. I will be working over what I have saved.... for this I am thankful as some of the replies and postings, while not fully understood by me, had information that I never knew and I will be attempting to make some practical application of it, if for no other reason than to make some meaningful "fudge" numbers in my desktop dyno program.

I believe that this discussion may never be "over" .... if Taper41 comes back on here and posts some interesting facts obtained via his studies, I for one will be interested in what he will have to say....

Wishing you all "happy posting"....
Dave

   Even all us armchair experts

[fastman614]

Fastman, here is my post that taper thought contradicted you. I don't think you'll argue with it.

if  you decrease the aerodynamic drag by 25% or add power by 25% would the result differ or be the same, if it was on the same vehicle?

Set unit values arbitrarily so power/drag ratio is 1.
Decrease drag by 25%, power/drag is 1/.75=1.33.
Increase power by 25%, power/drag is 1.25/1=1.25
Ergo, result differs, decreasing drag 25% gives superior result.

I think we've done all we can.

When dealing with engineers, there comes a time when engineers are best left to argue amongst themselves.... and we Maintenance/repair/installation technicians (who by trade designation, call ourselves millwrights) quietly go ahead and install or repair the item being argued about.... we then let the engineer(s), by process of elimination, figure out by what (or whose) method it was done... while we just stand back with a knowing smile .... knowing that the process will repeat and that the outcome(s) will be accomplished my much the same method the next time...

So, in Toronto, Ontario (Canada) the millwrights union local was incorporated in April of 1958. In 2008, they had stickers made for their hardhats that said something like - Millwrights Local 1454 - Incorporated April 15, 1958.... Making Engineers Look Good For Over 50 Years!

I don't profess a whole lot of real engineering expertise... I understand the math.... I can do A LOT of practical "on the job" engineering but with aerodynamics and how to make cars go fast, I know about 3 or 4 things....

1- Make sure that your car is built to "known" specifications (looking at other "fast" dragster type lakesters, I copied them)

Enhance the aerodynamics by what you see on any other fast cars. (With what I had to work with, I copied, to the best of my ability, the rear tail extension and top "fin" that Al Teague had on his streamliner - Al did not have a rear tail fin anywhere near as pronounced as most other fast cars)

3- "Buy" or otherwise procure as much horsepower as you can - even going in to debt to do so! (I bought a  "new" Dodge R5P7 engine that was massaged beyond NASCAR legality)

4- I chose a transmission with custom gear ratios that help keep the engine running within 7% of peak horsepower from the top of second gear on up...

It has resulted in record setting performance.... beyond this is guesswork on my part... and the farther away from these above that the guesswork takes place, the "less educated" of guesswork it is.

Like I inferred and perhaps said earlier, Taper41 - I wish you well in your schooling... I also hope you take a lesson or two from this exercise... If, for instance you compiled the more educated replies, made calculations and answers etc based on those replies and then asked for further input in the vent that you were not understanding the outcomes, you could have "ramped" the intellectual level of this thread up a bit.

I did also say that some of the information has already been filed away for my future reference. I will be working over what I have saved.... for this I am thankful as some of the replies and postings, while not fully understood by me, had information that I never knew and I will be attempting to make some practical application of it, if for no other reason than to make some meaningful "fudge" numbers in my desktop dyno program.

I believe that this discussion may never be "over" .... if Taper41 comes back on here and posts some interesting facts obtained via his studies, I for one will be interested in what he will have to say....

Wishing you all "happy posting"....
Dave

   Even all us armchair experts

Only if you think that I was referring to you..... hmmmmm....

[jl222]

  It was Experts not expert, [and I did think I was among them] showing your contempt and disrespect for everyone.

  Next time you refer to anyone as an ''armchair expert'' I WILL repost your threat as an inspector to fail a fellow

posters car.

             JL222

               

[Glen]

WHAT HAPPENED TO THE IGNORE BUTTON. That was handy with one click and we didn't have to read any post by any one person. 

[fastman614]

  It was Experts not expert, [and I did think I was among them] showing your contempt and disrespect for everyone.

  Next time you refer to anyone as an ''armchair expert'' I WILL repost your threat as an inspector to fail a fellow

posters car.

             JL222

               

I perhaps should post my personal message to you on this page, right?  Or, perhaps I should go through this thread and collect your posts and then repost them all in one.....

Whatever you say Mr Langlo.....

[taper41]

I know that some of these question i have might be elementary to you folks that are veterans at this but please help to inform me of some of the simple questions due to a study that i have been doing for physics....

in a perfect world where traction was not a problem, when trying to reach top end speeds, is it more advantageous to have the streamliner equipped with 4 wheels like a tradition car or 2 wheels like a tradition motorcycle, lets keep the wheels all at the same with for either vehicle for a controlled variable and say that both liners have the same weight and power along with same dimensions. theoretically wouldn't the motorcycle style have a lower drag thus  enabling it to reach higher speeds.

from the outside looking in i dont understand how the 4 wheel streamliners have been able to reach higher top speeds
wouldnt the 2 wheel design be more efficient for top speed

as silly as this might be i thank whomever helps me with this

  First it's a perfect world were traction is not a problem, then you refer to the current record speeds set on a track were distance and traction is a problem.

  Thats why 4 wheels and hp rule.

  Inputing and refining data in the Bville Pro program shows why.

           Starting data 1208 hp CD .300  gearing  2.3   mph after 1 mile 213   2 miles 245  3 miles 257  4 m 263  5 m 265

          -25% CD        1208 hp CD .225    ''        2.15   ''             ''    218       ''      253     ''       270   ''    280   ''  284

          +25% HP        1510 HP CD .300    ''        2.1    '''            ''     231       ''       263     ''      279    ''   285   ''  289

        At the finish the lower Cd is catching up but Bville Pro only goes 5 miles

       Also the program is optimistic on acceleration as it won't input the 4'' wide tires used by most.
       But we have been ahead of program inputs at El Mirage [which has better traction than Bville] with the 222 camaro


                    JL222   
 

This is what i don't get, you torture me for a few days then come up with data which explains what i was asking.  That's all i wanted in the first place.
I see at the end that the vehicle with the 25% drag increase is catching up, but will it eventually  top out at a certain speed , equal to the car with the power change , or would it just keep going with no end

[tortoise]

This is what i don't get, you torture me for a few days then come up with data which explains what i was asking.  That's all i wanted in the first place.
I see at the end that the vehicle with the 25% drag increase is catching up, but will it eventually  top out at a certain speed , equal to the car with the power change , or would it just keep going with no end

Taper, what you should take away from jl's simulation is that the numbers are close. Simulating a different car the numbers could go the other way. And no model precisely duplicates the real world. Otherwise they could just send the simulation in and not run the car.

[taper41]

i see that the numbers are very close indeed but what I'm saying is once the car hits 289 should it hit a wall and top out at the apx. same speed as the car with the change in horsepower coming out with the same result or would it be better

[tortoise]

i see that the numbers are very close indeed but what I'm saying is once the car hits 289 should it hit a wall and top out at the apx. same speed as the car with the change in horsepower coming out with the same result or would it be better

The program he uses calculates for only up to the distance he shows. But as you see, each "car" is picking up less and less each mile. They're nearing top speed. Read "where should the power be" in Bonneville General Chat for an interesting discussion about some factors other than maximum power and drag that affect speeds. You'll note I don't have much to contribute to that one.