Rifle: A machine rated in horsepower

[4Mesh]

My e-mails to Henry are many months old and why this one was put in storage alludes me at this moment.I believe Henry included a witty remark and tat is whar I thought was being saved.Henry never sent me this after reading this thread.It is likely 6 months old or older.
I didn't do any proofs because none of the numbers presented here are close.I've seen 5,000 hp and I've seen 0.669 hp given.
Hp is a rating just like the rating of a firearm.Has anyone here ever fired 700 rounds in one minute using an M1? The answer is of course "no" because it is a rate of fire even though nobody shoots one for 10 minutes straight and uses 7,000 rounds.
I would also not expect a 220 gr bullet with a rated
hp of 4500 move a 550 pound weight 3,002 feet.
If Jettmug has ever been on the track a simple push with your hand will move the car during the burnout.Very little of the 5,000 hp rating is ever applied to the track.
Lynn

Lynn, I saw long ago when you first talked about the email before it was even yet posted, that it was many months ago. I did read the thread, though I have missed some minor things. This is why I said it was quoting him without his say. That was LONG before this thread ever existed.

This units conversion mistake has been floating around this board for a VERY long time. Well before 6 months ago, and I mean well before. I have avoided discussions such as this in the past, not because I had nailed down this error, but because I could see with my eyes closed that something was wrong, but didn't know what. And I didn't want to get in some over the top discussion like this one. Unfortunately for me, I did get in this one and tried an example of my own. Suffice to say, I dont' think that will happen again.

I'll be honest, I do not like this sort of discussion. The time and effort it takes is insane, and then just as has happened here, someone changes the rules halfway and makes everyone wrong, in spite of there being a clear answer with the original parameters.

I have no doubt that Vibe went to work again today and won't reply for some time. I got a bit ahead of myself (for lack of better words) and removed a post that wasn't ready yet for discussion since we had not addressed the last issues.

Believe me when I say, when this is all over with, Vibe is going to look back and re-read this entire thread in detail, and very early on will say, OMG!!!! What was I thinking?

If I had to guess, Vibe is the unfortunate victim of a professor who used some coined phrase somewhere along the lines, and that phrase stuck with him. Something to do with energy and work or energy and power being the same thing. Some PART of the phrase is misleading, and he has said that several times in this thread about the energy = work or something to that effect. Let's not nitpick and go show that this isn't the word for word quote, it's the general meaning that he's expressed. The professor was wrong with some wording, or left out something and Vibe bit, line hook and sinker as he should, assuming the professor was right.

A similar such phrase that becomes a semantic hole of quicksand is quoted here on this board regularly. I choose not to point it out, as I think it is more fun to see how it affects the entire shooting community as a whole! And boy does it!

 

[alinwa]

BTW vibe, I owe you a big THANK YOU!!!

I have thought for years that a slug was a pound-equivalent, kinda' like the poundal.

I WAS WRONG!

Thank you man, a slug is just over 32lb @MSL etc etc.

I love this stuff!

al

 

[Jetmugg]

Bwahahahaha.

If Jettmug has ever been on the track a simple push with your hand will move the car during the burnout.Very little of the 5,000 hp rating is ever applied to the track.
Lynn

If Lynn has ever been on the track, he would know that top fuel cars do not do a "line lock" type of a stationary burnout. Let the fueler finish the burnout, back up, stage, and start the christmas tree. Now try to hold it back. Perhaps you could use a water ski rope, and just yell "HIT IT" when you feel like you have your feet planted.

SteveM.

 

[4Mesh]

Vibe,

When you get back from work, or tomorrow, please re-read my posts 16 and 26. These address the fundamental mistake that's being made by an entire host of people who are "cheating" if you will by taking an energy number from their balistics program and then trying to use it as a parameter for this problem.

In your post #66, you clearly state (though you did it a number of times earlier) that the units for energy and work(power) are the same thing with seconds strapped on to the power one. This is the error you and others are making. Those units are not the same, despite the fact that they are expressed the same way. Ft Lbs can be both an energy, or a force, and the two are not even close to the same thing. As an energy it is intantaneous, but as a force, it relates to time. They are not interchangeable.

Man, this thread is too long to go backtracking through all the time. I nearly installed an old copy of MathCAD I have laying around here! hehe.

EDIT =====

Oh, and by the way, I do see now where we have been working with a defined barrel length since the onset, even if we didn't know it. If you use my simplified example and the 3000 ft / sec MV, and any one of the time in barrel examples for calculating HP, the barrel length can be calculated by using the velocity and the time we state the bullet is in the barrel. No matter though, regardless if we say the barrel is 1 foot or 3000 feet, it does not change the numbers because time adjusts with it inversely proportionate. (greatly simplified of course)

 

[alinwa]

BTW, since't we're regressing, digressing, revisiting and gener'ly recessing....... you'se were comparing ballistic pendulum stories cool.

I never built the pendulum but I DID build and execute the "Monkey in a Tree" experiment in my high school physics class........using a dartboard, an electromagnet and a Huarache blowgun.

There, got MY brag in too


LOL


al

 

[4Mesh]

Al,

When I think back to my younger days and remember all the stuff I built, I'd have to say it's a miracle I'm alive!

 

[Vibe]

In your post #66, you clearly state (though you did it a number of times earlier) that the units for energy and work(power) are the same thing with seconds strapped on to the power one. This is the error you and others are making. Those units are not the same, despite the fact that they are expressed the same way. Ft Lbs can be both an energy, or a force, and the two are not even close to the same thing. As an energy it is intantaneous, but as a force, it relates to time. They are not interchangeable.

You mean here?

Work has the same units as Energy because that's what it represents Ft-Lbs...Ft-Lbs/sec is a description of Power - Work per unit time.

No mistake there. The units are correct.
Ft-lbs can be Work, or Energy...but NEVER a Force as those two are definitely NOT the same thing. Force is simply Pounds, or the real units of
Slug-ft/sec^2 in the pound-foot-second system.
(The ft-lbs used to describe torque is another matter and we don't want to go there right now)
And the units of Power are the units of work (and or energy) divided by the time involved in doing the work or changing the energy.

 

[4Mesh]

I'm gonna be perfectly honest with you. You have me so frustrated with trying to dream up new ways to say this that I am begining to make errors myself. Kinda like the post where I asked you to write in there 4Mesh is wrong, when 4Mesh isn't. Please be sure to gain entertainment value from this and don't take me too seriously as I fear may be happening. Those who know me will tell you that I'm really a hell of a good sport about stuff and it's all a friendly rib'n that I take probably better than I give out.

Now. I'm going to say this. You have avoided my math for so long it's starting to wear thin with me. My language skills are not broad enough to come up with many more ways to tell you the same things I've said. Without learning German or Dutch and saying it that way I'm "runnng out of bullets" Vibe.

I implore to you, PLEASE answer my questions. Now, I'm going to re-word and re-post a question I asked you some time ago and ask you to address it.

Also, Have you re-read this thread from start to finish? When the light clicks on, I know you're going to fall off your chair.

Here goes.
removed quotes because it's really not a quote, and it does make it hard to read.

Listen, I disagree with a fundamental part of your position.

You are saying that ft lb energy is the same thing as ft lb sec of power. I disagree.

Fixing that statement, I should have said (and I am sorry for this)
you say ft lb of ENERGY is the same thing as ft lb of WORK. But if you look at what you did, you DID turn it into power without even knowing it. Now, am I using the correct term on the second half there with "work" or should that be different? If that is a semantic error on my part, accept that and just answer the question that you know I'm asking. Please. Before typing anything about this, please read the next statements that I'm going to make more clear again hopefully.

Ok. I have a better idea. I'm going to take new easy values of units to do this calculation again and you tell me which is wrong, if either. we are going to take the same values for two items and calculate both the work in ft lbs and the energy in ft lbs.

Both cases. 10 lbs. Lift it 10 ft. Do it in 1/2 a second.

Now, don't nit pick the lift term. I'm trying to make this understandable for everyone.

10 x 10 = 100 FOOT POUNDS OF WORK. WORK WORK WORK WORK

Ok to here?

Now next, I do an ENERGY calculation on that same scenario. ENERGY ENERGY ENERGY

Remember, 70,000 grains is the same as 10 pounds.

70,000 grains x 10 feet in 1/2 of a second.

I'm going to use 20ft per second as an average velocity.

The answer is, 62.19 FOOT POUNDS OF ENERGY.
That is, 70,000 x 20^2 / 450240 = 62.19

62.19 <> 100 Correct?

Given that our velocity is small in ft/sec, the square does not become astronomically large and is only 400.

In this particular case, the velocity is low, and the calculation actually shows less energy in Ft Lbs than it does work in Ft Lbs. The number we use as a multiplier which is the SQUARE OF THE VELOCITY as stated MANY times before, does not show this example to be wrong by nearly as much as a larger velocity squared like 3000 ft/sec. With 3000 ft/s velocity, the error is so incredibly large that Stevie Wonder would be pointing this out in the dark.

BOTH THE EXAMPLES ABOVE USE Ft Lbs as an end result but the QUANTITIES DESCRIBE DIFFERENT THINGS. THIS IS THE ERROR I'VE POINTED OUT ALL ALONG. Please re-read post #16 at this time.

Ok. If you still do not see this, I am afraid that... I'm just going to keep my fingers tied and say that while someone may be able to help you, I am not the one. I'm trying to be as nice as I am capable of and show this but you're frustrating me with your pre-supposed answers and not working through my examples. You have not worked through MY examples even one time, and I have done yours COUNTLESS times and showed you so many different ways I'm exhausted.

All in fun. I do hope you've got it.

Please, promise me you will re-read this thread after you understand what it is I'm saying and after we have come to an agreement about the calculation of HP.

------------------------------------------------------
Sorry, but I have got a new way to add to this.

Think of it like this. Energy is directionless. Work is vertical. Does that help. Now do you understand why I kept referring to your examples working on a level plane and mine are in a vertical plane?

Also, think of the one ft lbs value as containing time, and the other does not. Again, on the energy value, you need to turn that back around into work, then come forward with the Power and HP calculations.

 

[Vibe]

You are saying that ft lb energy is the same thing as ft lb sec of power. I disagree.

So do I ..And as far as I know I have NEVER said that. They are NOT "the same thing"

 

[Vibe]

Ok. I have a better idea. I'm going to take new easy values of units to do this calculation again and you tell me which is wrong, if either. we are going to take the same values for two items and calculate both the work in ft lbs and the energy in ft lbs.

Both cases. 10 lbs. Lift it 10 ft. Do it in 1/2 a second.

Now, don't nit pick the lift term. I'm trying to make this understandable for everyone.

10 x 10 = 100 FOOT POUNDS OF WORK. WORK WORK WORK WORK

Ok to here?

Now next, I do an ENERGY calculation on that same scenario. ENERGY ENERGY ENERGY

Remember, 70,000 grains is the same as 10 pounds.

70,000 grains x 10 feet in 1/2 of a second.

I'm going to use 20ft per second as an average velocity.

The answer is, 62.19 FOOT POUNDS OF ENERGY.
That is, 70,000 x 20^2 / 450240 = 62.19

62.19 <> 100 Correct?

Given that our velocity is small in ft/sec, the square does not become astronomically large and is only 400.

In this particular case, the velocity is low, and the calculation actually shows less energy in Ft Lbs than it does work in Ft Lbs. The number we use as a multiplier which is the SQUARE OF THE VELOCITY as stated MANY times before, does not show this example to be wrong by nearly as much as a larger velocity squared like 3000 ft/sec. With 3000 ft/s velocity, the error is so incredibly large that Stevie Wonder would be pointing this out in the dark.

BOTH THE EXAMPLES ABOVE USE Ft Lbs as an end result but the QUANTITIES DESCRIBE DIFFERENT THINGS. THIS IS THE ERROR I'VE POINTED OUT ALL ALONG. Please re-read post #16 at this time.

OK. I see what you're asking I think...Give me a bit to work it out and make it clearer...but the main issue is in the difference in the "acceleration term"
The 10x10 example is working against 32 ft/sec^2 while the 70000 grain example is taking a difference in velocity.
One is an MgH problem, the other is an MV^2 calculation...you cannot simply equate the two.

10/32 Slug * 32ft/sec^2 * 10ft = 100 ft-lbs WORK
70,000grain * 1 pound/7000 grain * 1 slug/32 pounds * 32ft/sec^2 * 10ft = 100 ft-lb WORK

100 ft-lb WORK done in 0.5 sec = 100/0.5 = 200ft-lb/sec power

the 20ft/sec example is a bit different. IF you are saying that a 70,000 grain mass is traveling at an average of 20ft/sec and goes 10 ft...then no work was done, as the velocity did not change. IF on the other hand you are saying that it started at 0 velocity, and traveled 10 ft under constant acceleration in 0.5 sec resulting in an average speed of 20 ft/sec...then the final speed is 40 ft/sec at the end of that time period V(ave)=(V2-V1)/2 then if V1 =0, then V2 has to equal 2V(ave)

10/32 Slug * 40 * 40 ft^2/Sec^2 = 0.3125 * 1600 Slug ft/sec^2 - ft = 500 ft-lbs work

500ft-lbs work done in 0.5 sec is 500/0.5 = 1000 ft-lb/sec power.

If you are saying that this happened in a straight up direction then the previous 100 ft-lb of work due to change in potential has to be added to the 500 ft-lb kinetic energy increase due to velocity.
SO total work in this particular case would be 600ft-lbs
done in 0.5 sec would be 1200 ft-lb/sec of power.

Sorry this took so long. I had a virus crash during posting and have been diagnosing that as I posted.

 

[4Mesh]

100 ft-lb WORK done in 0.5 sec = 100/0.5 = 200ft-lb/sec power

the 20ft/sec example is a bit different. IF you are saying that a 70,000 grain mass is traveling at an average of 20ft/sec and goes 10 ft...then no work was done, as the velocity did not change. IF on the other hand you are saying that it started at 0 velocity, and traveled 10 ft under constant acceleration in 0.5 sec resulting in an average speed of 20 ft/sec...then the final speed is 40 ft/sec at the end of that time period V(ave)=(V2-V1)/2 then if V1 =0, then V2 has to equal 2V(ave)

10/32 Slug * 40 * 40 ft^2/Sec^2 = 0.3125 * 1600 Slug ft/sec^2 - ft = 500 ft-lbs work

500ft-lbs work done in 0.5 sec is 500/0.5 = 1000 ft-lb/sec power.

Look there, you just took the same input units and came up with 200 <> 1000 units of power. It's off by a factor of 5 and this is a really small error as compared to what's been done here since page one of the thread.

========= 4Mesh leaves a huge sigh, shakes his head, closes his eyes and asks for God to intervene here. ==========

Will you PLEASE LET ACCLERATION OUT OF IT. FORGET IT. Nada, it is not there. The vessel is not accelerating in example two, it is floating in space. Stop trying to figure how it got up to speed.

Listen, when we lift the weight we lift it 10 feet. Might take a day, might take .01 seconds. The same amount of work is done. Time is imaterial.

When we calculate velocity, we do not need to know how fast the bullet accelerated. When we calculate downrange energy of a bullet. Let's say we have a MV of 2000 ft per second. Is the energy any different in that bullet than it is in a bullet that started at a MV of 10000 fps and slowed to 2000. When they both reach 2000 fps, they have the same energy if they weigh the same. In all truth, I hate that we have to qualify obvious statements like, yes the same bullet.



We used 20 ft per second as an AVERAGE velocity only because during that time it moved 10 ft in 1/2 second. We do not care how much time it took to get up to speed. Technically here YOU ARE CORRECT ON A POINT, the ending velocity will not be 20ft/second if there was an acceleration phase. Here's two better examples and you choose the one you want to use. They are the same end result. The 10 pound weight is sliding at 20ft per second across a perfect frictionless plane and has been so at the same speed for a decade. How much energy does it have? The acceleration rate is NO PART OF IT.

Or, the 10# weight magically accelerated to 20ft/sec exactly in NO TIME and traveled the 10 feet at the exact rate of 20ft/s. Use either. Sorry to keep changing my mind but you keep bringing in more things that do not apply.

If you are saying that this happened in a straight up direction then the previous 100 ft-lb of work due to change in potential has to be added to the 500 ft-lb kinetic energy increase due to velocity.
SO total work in this particular case would be 600ft-lbs
done in 0.5 sec would be 1200 ft-lb/sec of power.

Sorry this took so long. I had a virus crash during posting and have been diagnosing that as I posted.

That last paragraph I'm not going to address as in my mind it is not even applicable to our discussion. It is unfortunate that I need to keep adding more default parameters to the same problem eliminating parts that you keep bringing into it. All I can say is you are making this vastly more difficult than it is.

No problem on the computer issues. Deal with work first. (not to be confused with lifting boxes!).

 

[4Mesh]

And Al, Bill, or someone here, please take over this discussion with a fresh point of view before ole 4Mesh is eating a can full of DynaCirc CR's for lunch I don't deal well with these sorts of things anymore. My teaching days were over a LONG time ago!

 

[Vibe]

Look there, you just took the same input units and came up with 200 <> 1000 units of power. It's off by a factor of 5 and this is a really small error as compared to what's been done here since page one of the thread.

No errors, just trying to cover all of your scenarios.

Will you PLEASE LET ACCLERATION OUT OF IT. FORGET IT. Nada, it is not there. The vessel is not accelerating in example two, it is floating in space. Stop trying to figure how it got up to speed.

Listen, when we lift the weight we lift it 10 feet. Might take a day, might take .01 seconds. The same amount of work is done. Time is imaterial.

When we calculate velocity, we do not need to know how fast the bullet accelerated. When we calculate downrange energy of a bullet. Let's say we have a MV of 2000 ft per second. Is the energy any different in that bullet than it is in a bullet that started at a MV of 10000 fps and slowed to 2000. When they both reach 2000 fps, they have the same energy if they weigh the same. In all truth, I hate that we have to qualify obvious statements like, yes the same bullet.



We used 20 ft per second as an AVERAGE velocity only because during that time it moved 10 ft in 1/2 second. We do not care how much time it took to get up to speed. Technically here YOU ARE CORRECT ON A POINT, the ending velocity will not be 20ft/second if there was an acceleration phase. Here's two better examples and you choose the one you want to use. They are the same end result. The 10 pound weight is sliding at 20ft per second across a perfect frictionless plane and has been so at the same speed for a decade. How much energy does it have? The acceleration rate is NO PART OF IT.

Or, the 10# weight magically accelerated to 20ft/sec exactly in NO TIME and traveled the 10 feet at the exact rate of 20ft/s. Use either. Sorry to keep changing my mind but you keep bringing in more things that do not apply.

I covered that possibility

IF you are saying that a 70,000 grain mass is traveling at an average of 20ft/sec and goes 10 ft...then no work was done, as the velocity did not change

And if it was somehow traveling in an upwards direction at a constant 20ft/sec, again only the 100 ft-lbs of work is done against gravity requiring the output of 200 ft-lbs/sec of power.

 

[Jetmugg]

Where is the rifle pointing?

I think that 4Mesh is pointing his rifle straight up when it is fired.

Vibe is firing his level with the ground.

Are these assumptions correct?

SteveM.

 

[Vibe]

I think that 4Mesh is pointing his rifle straight up when it is fired.

Vibe is firing his level with the ground.

Are these assumptions correct?

SteveM.

I've been wondering who would ask this first.
It really doesn't make much difference. After the bullet leaves the barrel, we are no longer "doing work" to it...It's on it's own. And the change in potential energy of a 200 grain bullet from chamber to 26" above the chamber is really really small compared to the energy in the velocity. I suppose I could do the math on it...if anyone was REALLY interested....but it ain't much. Much less than one ft-lb.

 

[4Mesh]

Alright, let's do completely fresh examples.

I see again that you're grasping at straws or it sure looks that way to me. You continue to skirt the issue quite well actually and my hat is off to you for laying down a line ....... what was the General's line used in Good Morning Vietnam?

It looks like I have to make this more clear yet. While everyone else in the world knows what was being assumed, you are now playing the witty engineer who is going to try to use technicalities which are not relavant to the discussion, to say someone else is wrong (however slightly) and hope that they just go away with you not admiting you are the one who is off by roughly 50,000 times or so. That of course in the earlier examples. Now you're just off by 5 times because I made the velocity smaller. Here again, it's gonna get bigger.

I'll use one second as my elapsed time for the work and velocity is going to be expressed in ft/sec with no seconds specified.

Ok. Here goes. Once again, Please correct the part I do wrong.

1 pound. Lift 100 ft against gravity. Do the work in 1 second. 100 ft lbs of work. 100 ft lbs/sec of Power.

1*100 = 100 ft lbs.
1*100/1 = 100 ft lbs /sec

Now. 1 pound travelling at 100 feet per second. Calculate the energy we are dealing with. Remember, this is what YOU have done since the onset. Please don' t go back and delete all your posts to bury the dog dirt as others have done, it lacks character.

1 pound. 100 ft/s
1 pound = 7000 grains used for input to this equation.

7000 * (100^2 or 10,000) / 450240 = 155.47 FOOT POUNDS ENERGY.

Once again. 155.47 ft lbs energy does not equal 100 ft lbs of work.

Now, just to save a lot of time, which one of us used the WRONG one since this thread began? Which one Vibe.

Will you ever own up to this?

 

[4Mesh]

Ummm, what is this BS about when is someone going to ask about horizontal vs vertical????? I've said that till I was sick of saying it. Matter of fact, I said about everything here enough times that it would have sunk in to ANYONE ... LONG ago.

I think it is time for Vibe to begin his long day re-reading this thread and then get back to us. I'm sure he will especially enjoy all the red "4Mesh is WRONG HERE" lines. Especially when they are WRONG.

 

[Vibe]

1 pound. Lift 100 ft against gravity. Do the work in 1 second. 100 ft lbs of work. 100 ft lbs/sec of Power.

1*100 = 100 ft lbs.
1*100/1 = 100 ft lbs /sec

Now. 1 pound travelling at 100 feet per second. Calculate the energy we are dealing with. Remember, this is what YOU have done since the onset. Please don' t go back and delete all your posts to bury the dog dirt as others have done, it lacks character.

1 pound. 100 ft/s
1 pound = 7000 grains used for input to this equation.

7000 * (100^2 or 10,000) / 450240 = 155.47 FOOT POUNDS ENERGY.

Once again. 155.47 ft lbs energy does not equal 100 ft lbs of work.

Now, just to save a lot of time, which one of us used the WRONG one since this thread began? Which one Vibe.

Will you ever own up to this?

Well the first one works out right.

Grains is not a unit of MASS
1 pound * 1 Slug/32 pounds = 1/32 Slug
(100ft-sec)^2 = 10000 ft^2/Sec^2

1/2 MV^2= 1/2 * 1/32 * 10000 Slug-ft/sec^2 - ft = 156.25 ft-lbs of energy but represents no "work done" as there was no velocity change.

I think I left out the 1/2 factor in the virus crash post. Sorry.

And no the two values are not equal...why would they be?

I'm assuming that you want the 100 ft/sec to be a constant velocity in the upwards direction. In which case there was 100 ft-lbs of work done in 1 sec for 100ft-lbs/sec of power. No additional power was required to increase the velocity so 1/2M(delta)V=0 ft-lbs. 100 + 0 =100 Ft-lb work done.

 

[4Mesh]

Grains is not a unit of MASS
1 pound * 1 Slug/32 pounds = 1/32 Slug
(100ft-sec)^2 = 10000 ft^2/Sec^2

1/2 MV^2= 1/2 * 1/32 * 10000 Slug-ft/sec^2 - ft = 156.25 ft-lbs of energy but represents no "work done" as there was no velocity change.

I think I left out the 1/2 factor in the virus crash post. Sorry.

And no the two values are not equal...why would they be?

I'm assuming that you want the 100 ft/sec to be a constant velocity in the upwards direction. In which case there was 100 ft-lbs of work done in 1 sec for 100ft-lbs/sec of power. No additional power was required to increase the velocity so 1/2M(delta)V=0 ft-lbs. 100 + 0 =100 Ft-lb work done.

Forget that crap. I KNOW GRAINS ISN'T A MASS. That's why we use a constant of 450240

 

[4Mesh]

And no the two values are not equal...why would they be?

Because you have used these interchangeably SINCE THE DAWN OF THIS THREAD.

No, I'm not nitpicking about the 1/2 left off... We know where the thing is supposed to be headed. This entire excercise is suppose to be showing what you did wrong in the earliest example. PLEASE go BACK to the beginning and you will see answers off by 40 or 50 THOUSAND times the real quantity.