View Full Version : Rifle: A machine rated in horsepower

Bill Wynne

06-11-2009, 11:20 AM

But the question was asked, I answered factually...You argued. :D

And here we are. :p

Yes, Here we are!

Your facts have confused you. I am sorry. I am content to leave you there with your thoughts but I feel the need to shed the light of truth on the subject so others will not be lead astray.

If we ever meet, I will buy you a cup of coffee but we must not discuss horsepower or rifles.

Concho Bill

pacecil

06-11-2009, 01:19 PM

Bill Wynne says I feel the need to shed the light of truth on the subject so others will not be lead astray

That's ok, but the light you are shedding is simply not true!

Bill Wynne

06-11-2009, 08:28 PM

Look Pacecil and Vibe. The need for the unit of power called "Horsepower" was devised a long time ago when engineers were not as smart as they are now. Think about it, Why would anyone try to compare the power of a steam engine with the power of a horse. That fellow was not the sharpest pencil in the box but he did the best he could. He did not even have a computer to help him with his calculations. He did all this in an age before long division was clearly understood.

He had to keep it simple or else the math would have eaten him up hair and all.

You guys are way smarter than that guy so you can make it far more complicated than he could handle.

A simple man can do just so much. Because I am simple too, I understand the problem and can reach the conclusion.

Concho Bill

pacecil

06-11-2009, 11:44 PM

I was telling my neighbor about my new car the other day. That thing will do a 150 mph. He said ,wow, how much horsepower that thing got? I said, I don't know but lets see.

A 150mph is 220 fps. The car weighs 2500 lbs.

2500 X 220 will give us 550000 ft-lbs/sec.

And then we'll divide that by 550 to get horsepower.

Gives us 1000hp!

That seems like a lot of power from that little four cylinder engine. What did I do wrong?

Bill Wynne

06-12-2009, 05:43 AM

I was telling my neighbor about my new car the other day. That thing will do a 150 mph. He said ,wow, how much horsepower that thing got? I said, I don't know but lets see.

A 150mph is 220 fps. The car weighs 2500 lbs.

2500 X 220 will give us 550000 ft-lbs/sec.

And then we'll divide that by 550 to get horsepower.

Gives us 1000hp!

That seems like a lot of power from that little four cylinder engine. What did I do wrong?

You got me there. That is a great car.

I am going to have to let you have that one on shear cleverness.

The only thing that I could think of is that your car would have to lift 2500 pounds 220 feet in one second after overcoming the initial effects of inertia to exhibit 1,000 horsepower. What do you think?

Concho Bill

I was telling my neighbor about my new car the other day. That thing will do a 150 mph. He said ,wow, how much horsepower that thing got? I said, I don't know but lets see.

A 150mph is 220 fps. The car weighs 2500 lbs.

2500 X 220 will give us 550000 ft-lbs/sec.

And then we'll divide that by 550 to get horsepower.

Gives us 1000hp!

That seems like a lot of power from that little four cylinder engine. What did I do wrong?

Same thing Bills been doing. Trying to equate Momentum with power, and Lbs weight with Lbs Force. How fast will it get to 150mph?

Bill has come to his simple conclusion, and it doesn't seem to bother him in the least that that conclusion is incorrect.

Bill Wynne

06-12-2009, 08:28 AM

Bill has come to his simple conclusion, and it doesn't seem to bother him in the least that that conclusion is incorrect.

I am comfortable with my opinion. Why would I need yours?:)

That's my story and I am sticking to it.:)

Concho Bill

I am comfortable with my opinion. Why would I need yours?:)

That's my story and I am sticking to it.:)

Concho Bill

LOL. I don't suppose that you would need my "opinion", but my position in this matter is more than mere opinion, it can be proven and reproduced through experimentation. Your position cannot be. :D

pacecil

06-12-2009, 06:23 PM

You remarked: The only thing that I could think of is that your car would have to lift 2500 pounds 220 feet in one second after overcoming the initial effects of inertia to exhibit 1,000 horsepower. What do you think?

I'm not sure why but you did ask what I think. You seem only able to comprehend horsepower as a "lifting" action, so I'll just go along with you. You can use what I'm about to say any way you want, that is you can try to understand it, or you can ignore it as you have mostly done in the past.

I won't go into the calculations required because you would simple ignore them. Here's all I'll say: You must determine how much force you need apply to underside of car to cause it to accelerate from zero fps up to a speed (This turns out to be 440 fps.) necessary to get the car 220 ft up in the air in one second. You must multiply the acceleration times the weight (mass) of the car to get the required force. (Force =Mass X Acceleration or F=Ma. This tiny equation governs your entire life. You better believe this even if you don't believe anything else!) If you do all this you arrive at a force of 19687 lbs, (Note, you don't just have "initial inertia" - you got it all the way up!)

Now comes the part where we leave you - determining the horsepower it requires to do this lifting. If we apply that 19687 lbs force all the way up to 220 ft and do it in one sec we will do 4331140 ft-lb/sec of work. This is equivalent to 7874 horsepower. So that's what it takes to lift 2500 lbs 220 ft in one second. (Back to that inertia thing - almost 90% of the work done here is overcoming inertia of the moving weight. The other 10% is just to lift the weight up off the ground.) ( I decided to add this maybe to make you feel better about your 1000hp: If you wanted to just lift the car very slowly up off the ground, you could do this with about 800 hp.)

Now I know this doesn't compare to your method of multiplying 2500 lbs times 220 fps and dividing by 550 to get 1000 hp. But just study and think about it for a while

Bill Wynne

06-13-2009, 10:00 AM

Lynn,

Thank goodness you stepped in. Let me explain. I am being boxed about by two sharp minded engineers. They have ganged up against me but I am about to outsmart them. (Be sure to read to the bottom.) You can be an honest, non-bias, independent broker and listen to my the facts. Please bear with me.

The history of the term horsepower: In the last quarter of the 18th century James Watt while trying to sell his steam engine was searching for a way to explain the power it could produce. In those days horses were common. Everyone moved about and did work with horses so he sought to explain the power of his engine against the work that a horse could do.

He studied what amount of work could be done by a mill horse who walked around an 12 foot circle moving a millstone. These horses were draft horses not riding ponies. They were powerful animals. He determined that a horse could pull with a force of 180 pounds for his whole shift. At the rate the horse walked that amounted to of 33,000 foot pounds per minute or 550 foot pounds per second. This means the horse could lift 550 foot pounds per second for a long time. Mr. James Watt used that as the definition of one horsepower. (1 horsepower = 33,000 foot pounds per minute = 550 foot pounds per second)

You see, Lynn, this was an very unusual definition by today's standards but it is based on an factual observed events. If you will notice it says nothing about kinetic energy or the square of anything. It is a simple definition that simple men would understand. Engineers by their nature complicate the simple because that is what they do.

Lynn, I have given you the definition of a horsepower that James Watt gave people in his day. Take any rifle and any bullet at any given muzzle velocity and see what you come up with.

Going back to the Montana Pete's question.

This was his question: "Can you take a specific cartridge in a specific rifle and determine the horsepower generated by the rifle?"

Without going into detail, the answer to that question is yes.

Concho Bill

pacecil

06-13-2009, 10:55 AM

While were waiting on a reply from Lynn I decided to give you a little more to think about. I think I see why you aren't able to get a handle on this whole horsepower thing. Those guys that worked out a definition for a horsepower, could have used the force it took to drag the weight over the ground instead of lifting it.

Take a look at the lifting of the car. If instead of calculating what it take to lift the car, you calculate what horsepower it takes to drag or push the weight 220 ft horizontally in one second. For that matter you can determine what it takes to push it down a 220 ft hole in one second! When you lift the car weight adds to the horsepower, when you push the car horizontally the weight doesn't effect the power, when you push the car down a hole the weight adds to power. If you did the math you would find it takes 7874 hp to lift the car, 7086 hp to push it horizontally, and only 6299 hp to push it down the hole.

WHAT ALL THIS MEANS IS THAT THE INERTIA FORCE PLUS THE WEIGHT IS WORKING AGAINST YOU WHEN YOU'RE LIFTING, THE INERTIA FORCE IS AGAINST YOU BUT THE WEIGHT FORCE IS AT 90 DEG TO THE DIRECTION YOU'RE PUSHING WHEN GOING HORIZONTALLY, AND THE WEIGHT FORCE IS GOING SAME DIRECTION YOU ARE BUT INERTIA FORCE IS STILL AGAINST YOU WHEN PUSHING DOWN A HOLE.

I looked back at what I just wrote and maybe it'll just confuse you more, but I went to all trouble to write it so I'll let it fly and see what happens!

Bill Wynne

06-13-2009, 11:31 AM

Those guys that worked out a definition for a horsepower, could have used the force it took to drag the weight over the ground instead of lifting it.

Pacecil,

I would think that they used something like a spring cotton scale that retracted to the 180 pound mark as the horse walked his circle. The scale would not know if it was measuring a lifted weight or a resistance being drug along.

I am enjoying this interplay. There is no way we can be too serious about this.:)

Concho Bill

When you guys get done figuring out what "Work" really is (Becasue that is all that you have discussed), THEN you can determine how much POWER it takes to do that work in 0.002 seconds. :D

Bill Wynne

06-13-2009, 04:21 PM

After a life time in construction I know what work is. I come from a time before forklifts and nail guns and even before air condition pickups. I know what work is and I know something about manual labor and mechanical advantage. We worked with our backs and our legs and our arms. We also used our heads or else we wouldn't be here to keep you in line.:)

Concho Bill

After a life time in construction I know what work is. I come from a time before forklifts and nail guns and even before air condition pickups. I know what work is and I know something about manual labor and mechanical advantage. We worked with our backs and our legs and our arms. We also used our heads or else we wouldn't be here to keep you in line.:)

Concho Bill

The term "Work" in physics is not exactly the same as what we think of as "Labor" in the real world. You can push all day on a wall to keep a pig from settling into a newly laid row of brick, and you will be tired and hot when it gets to where you do not have to steady it. But you will have done no "Work" as far as the kenematic physics are concerned.

My momma didn't have much luck keeping me in line. :D You, my friend, don't have a shot. :D

Bill Wynne

06-13-2009, 04:51 PM

The term "Work" in physics is not exactly the same as what we think of as "Labor" in the real world. You can push all day on a wall to keep a pig from settling into a newly laid row of brick, and you will be tired and hot when it gets to where you do not have to steady it. But you will have done no "Work" as far as the kenematic physics are concerned.

My momma didn't have much luck keeping me in line. :D You, my friend, don't have a shot. :D

Well, at least I know what a horsepower is.:)

First I would get the pig out out of the row of bricks so someone who hadn't done any work at all wouldn't come by and ask a dumb question like, "What is that pig doing in that wall?" Then I would learn how to spell kinematic physics before I tried to use the word.:)

My mother kept me in a straight line and I have no trouble calmly taking another shot after a miss.

Concho Bill

Well, at least I know what a horsepower is.:)

Well you certainly know how to SAY that you do anyways.:D

[First I would get the pig out out of the row of bricks so someone who hadn't done any work at all wouldn't come by and ask a dumb question like, "What is that pig doing in that wall?"

LOL. See I do know what work is, and what a pig in a wall is.

[Then I would learn how to spell kinematic physics before I tried to use the word.:)

Hey. My spellchecker doesn't seem to work real well in IE, and I've only been posting in between batches of processing the honey I robbed from the bee hives today. ('bout 3 gallons from 2 hives). Besides, I know you read typonese alot better than you can cypher. :D

My mother kept me in a straight line and I have no trouble calmly taking another shot after a miss.

Concho Bill

And yet you refuse to "calmly take another shot" at understanding this horsepower stuff. :D

Hard headed old coot. :p

Bill Wynne

06-13-2009, 06:15 PM

Hard headed old coot. :p

Whippersnapper!

Concho Bill

Whippersnapper!

Concho Bill

At 53 (next month :D) It's been a while since I've been called that.:D

Well, at least I know what a horsepower is.:)

Concho Bill

I got one for ya Bill

How many horsepower is a 1500 watt steam iron? It ain't got much recoil at all. LOL.

(I looked at your website, so I figured you should know).

http://www.convert-me.com/en/convert/units/power/power.horsepower.en.html

Bill Wynne

06-13-2009, 07:08 PM

Lynn,

How would I know why these two smart people can't get their stories straight? Maybe they were educated beyond their IQ.

This just proves that even intelligent people can come up with different conclusions over what would seem to be a simple problem that surely has one simple answer.

Vibe,

It seems that a 1500 watt iron uses the equivalent of 2.0115331 horsepower or 85.0303543 BTUs (British thermal units) per minute or nearly 1/2 ton of air conditioning. I did not know that. That is a powerful hot iron. A lady can do a lot of work with an iron like that.

Concho Bill

pacecil

06-13-2009, 08:27 PM

I think I see the problem.♠ Everyone has a feel for how much power a horse could put out - or an automobile. But no body can understand in their gut what a rifle will do. If I show an example everybody can agree with and have a feel for all will be made right. That thing we went through about pushing a 2500 lb car up to 440 fps (300 MPH!!!!!) in one second was kinda stupid! (Was that your idea, Bill?)

So lets figure what it takes to accelerate my 2500 lb car up to 60 mph in, let's say 5 sec. We'll do it in the same 220 ft. The method we'll use is this:

Divide the final speed 60 mph(88 fps) by the time (5 sec) to get the acceleration. This turns out to be 17.6 ft/sec/sec. Then we'll use F=Ma to find out how hard we have to push against the car (or let the engine "push") to get the car up to speed. The mass of the car is 2500/32, multiplying this by the acceleration will give us the force which turns out to be 1375 lbs. If we apply this force over a distance of 220 ft and do it for 5 sec, 1375 x220/5/550, we find we'll need 110 hp to take the car from zero to 60 mph. (If you add a little more power to accommodate wind resistance and friction most people would consider this a pretty reasonable figure.)

Now if we follow the same procedure for a bullet we want to accelerate from zero to 3000 fps in 24 inches of barrel, lets just see how much power is required. It's going to be tough for anyone to have a feel for the numbers we come up with for the rifle because they are so far away from what the car was but they are figured just like the car was. Our bullet will cover the two feet of barrel at an average velocity of 1500 fps and take .0013 sec to do it. This equates to an acceleration of 1153846 ft/sec/sec. This is one of those numbers kinda hard to get a feel for, but consider this: we are making the bullet go from zero to 2045 mph in .0013 sec! In any case we go through the F=Ma thing again and find we must apply 1009 lbs of force to the base of the bullet over the 2 ft of barrel length. If it's a 30 caliber we only need apply an average pressure to the base of 13635 psi. Cranking all the numbers around just like we did with the car we finally will arrive at 2282 hp required to get that little sucker from zero to 3000 fps! Seems like a big number, but remember we only applied that power for .0013 sec.

THERE YOU HAVE IT - THE CORRECT ANSWER AND HOW YOU ARRIVE AT IT SHOULD END THIS THREAD.

THERE YOU HAVE IT - THE CORRECT ANSWER AND HOW YOU ARRIVE AT IT SHOULD END THIS THREAD.

One can always check the results by dividing the published muzzle energy by the time in barrel to get ft-lbs/sec and divide that by 550ft-lbs/sec/HP.

But that's a lot closer. :D

pacecil

06-14-2009, 08:35 AM

I just put that in there to see if anybody was watching! I used half the acceleration rate I should have. The correct horsepower is 4564

Bill Wynne

06-14-2009, 09:37 AM

Are there any engineers, science/math teachers, or others out there who love math?

Challenge: Can you take a specific cartridge in a specific rifle and determine the horsepower generated by the rifle?

Montana Pete

Look guys, This is a question that can be answered with either a simple yes or no.

In my case yes would be the correct answer. I will let it go there.

Look guys, This is a question that can be answered with either a simple yes or no.

In my case yes would be the correct answer. I will let it go there.

:D But in your case Bill (and only specifically in your case) the correct answer (according to your posts) is no. YOU can't. :p

We, on the other hand, have been able to do it. :D

eddybo

06-15-2009, 01:15 PM

I cant believe I just sat here and read this entire thread, but my interest got peaked. I was waiting to see if anyone tackled the fact that it takes substantially more effort to push a bullet down the bore. Wouldn't that artificially increase the weight of the bullet for purposes of determining horsepower, or would it just be akin to where the horse power is measured...ie rear wheels or flywheel. I am guessing the answers given would be considered rear wheel horsepower, other than the one poster who used muzzle pressure to derive his answer.

Very interesting thread, thanks for the information. I am very interest to know the answer to this question using these parameters: 3000fps, 210 gr bullet, 28 inch barrel, peak chamber pressure of 64,000 PSI. I guess I am wanting to know peak horsepower which would probably be calculated some where within the first three of four inches of travel. If I ran this through quickload and emailed someone the pressure curve would they give me an estimation?

I do not understand the math well enough to even take a shot, wish I could. While I am not very good at math, I was always good at taking standardized exams. I would have just marked the old standby "D. not enough information to answer" and moved on with this one.

Thanks again to all those who contributed to this interesting thread.

I cant believe I just sat here and read this entire thread, but my interest got peaked. I was waiting to see if anyone tackled the fact that it takes substantially more effort to push a bullet down the bore. Wouldn't that artificially increase the weight of the bullet for purposes of determining horsepower, or would it just be akin to where the horse power is measured...ie rear wheels or flywheel. I am guessing the answers given would be considered rear wheel horsepower, other than the one poster who used muzzle pressure to derive his answer.

Just like we usually do not consider the HP losses in your engine due to the drags from the alternator, power hydraulic pumps, or even how much it takes just to turn the engine as an air compressor - those are all internal, and (luckily) not part of this problem. :D

Very interesting thread, thanks for the information. I am very interest to know the answer to this question using these parameters: 3000fps, 210 gr bullet, 28 inch barrel, peak chamber pressure of 64,000 PSI. I guess I am wanting to know peak horsepower which would probably be calculated some where within the first three of four inches of travel. If I ran this through quickload and emailed someone the pressure curve would they give me an estimation?

Assuming that your pressure curve is approximately triangular - Approx linear rise to a peak, approx linear drop to muzzle exit, we can make some assumptions (it's not exactly that shape, but close enough for a few SWAGs)

The "average" of a triangle is 1/3 up. So the "peak" HP is going to be roughly 3x the "average" HP. Also the Average velocity will be closer to 2/3 your muzzle velocity rather than the 1/2 that I've been using for an estimate, so you time in barrel will really be shorter and you "average HP" quite a bit more than what's been stated here.

I do not understand the math well enough to even take a shot, wish I could. While I am not very good at math, I was always good at taking standardized exams. I would have just marked the old standby "D. not enough information to answer" and moved on with this one.

Thanks again to all those who contributed to this interesting thread.

I'd be quite a bit surprised that a rifle pushing a 210gr slug to 3000fps in a 28" barrel would generate any less than 20,000 PEAK HP. (For a few nanoseconds anyways) :D

But I didn't put a calculator to it.

Bill Wynne

06-15-2009, 04:45 PM

I am very interest to know the answer to this question using these parameters: 3000fps, 210 gr bullet, 28 inch barrel, peak chamber pressure of 64,000 PSI.

Eddybo,

Try to keep your mind clear and stay away from extraneous details. All you need to know is the velocity and the weight of the projectile.:)

Remember there is more that one position on this problem but only one correct answer. Let me try one more time.

Horsepower = 550 foot pounds per second.

210 grain bullet / 7000 grains in a pound = .03 pounds

At the time of the bang, your bullet leaves the muzzle at the rate of 3000 feet per second.

.03 pounds X 3000 feet per second = 90 foot pounds per second (a healthy recoil)

90 foot pounds per second / 550 foot pounds per second = .1636 horsepower

Concho Bill

Eddybo,

Try to keep your mind clear and stay away from extraneous details.

Concho Bill

Good advice here. Ironicly, it applies most to the postings by the poster giving the advice. :D

Bill Wynne

06-16-2009, 07:53 AM

Good advice here. Ironicly, it applies most to the postings by the poster giving the advice. :D

Ouch!!:)

Concho Bill

Bill Wynne

06-17-2009, 07:14 AM

...after 20 pages Vibe is entitled to a little pat on the back as he has been a very patient poster.

Waterboy

Lynn, Yes, Vibe is a patient poster and a good sport. He needs a pat on the back. He is a good sport and a thinking man. "Gladly would he teach and gladly would he learn." I cannot say enough good things about him and I will not say he is hard headed and just flat wrong. I am just better than that.:)

You are one of the good guys, Vibe.

Concho Bill

I suppose it is one of my failings. I really do enjoy helping someone else excel more than I like excelling myself. I really don't know how to handle success very well. But thanks guys.

Bill Wynne

06-20-2009, 06:17 AM

A 2,000 horsepower kick in the shoulder? Come on.:cool:

Concho Bill

A 2,000 horsepower kick in the shoulder? Come on.:cool:

Concho Bill

No. The rifle itself (barrel, action, stock) does not see anywhere near that much change in energy.

But even it will hit you harder than the seat of your 500hp Hemi when you drop the clutch. :D

pacecil

06-20-2009, 09:12 AM

I think I know Bill Wynne's problem. He hasn't grasped the fact that power is a RATE. When "horse" is added and it's no longer expressed in /sec units he forgets that horsepower is just "power" and is still ft-lb/sec. When a bullet is said to be capable of 2000 hp, he doesn't understand it is may be capable of this for only a very short TIME. It's like speed - when you say your car is doing 100 mph, it doesn't mean it is going to go 100 miles, or for that matter, that it will do 100 mph for an hour.

Everything is instantaneous - there 's no past or future - it's all NOW!

The views, the views....there's more than 10,000 views. Does that make this one of those "Big 'ol ugly threads"? Would Bill Calfee have problems wading through all the views?

:D

pacecil

06-20-2009, 04:30 PM

I'm about to make it uglier. (well maybe sillier!)

you said:

But even it will hit you harder than the seat of your 500hp Hemi when you drop the clutch.

I'm not so sure - I come up with the Hemi applying a force about 5X to your whole body, as compared to what the gun applies to your shoulder. All based on your shoulder knocked back an inch or two in maybe a hundredth of a second, while the Hemi takes your whole body a few hundred feet in, say, 5 seconds.

Bill Wynne

06-20-2009, 05:03 PM

No. The rifle itself (barrel, action, stock) does not see anywhere near that much change in energy.

But even it will hit you harder than the seat of your 500hp Hemi when you drop the clutch. :D

For every action there is an equal and opposite reaction. I wonder where Sir Newton went wrong and why no one else has noticed in the last 400 or so years.

What I like about physics, after you get past all the math, is that it is so simple.:)

Concho Bill

For every action there is an equal and opposite reaction. I wonder where Sir Newton went wrong and why no one else has noticed in the last 400 or so years.

What I like about physics, after you get past all the math, is that it is so simple.:)

Concho Bill

Geeze Bill. Power (and therefore HORSEpower) is a change in ENERGY per unit time. Newtons laws of motion deal in MOMENTUM. Momentum and energy are NOT the same. When shooting a rifle, momentum is conserved, energy is NOT.

No one ever even implied that the mV^2 of the bullet was in anyway related to the Mv^2 of the rifle. Least of all Newton. He knew better.

I'm about to make it uglier. (well maybe sillier!)

you said:

But even it will hit you harder than the seat of your 500hp Hemi when you drop the clutch.

I'm not so sure - I come up with the Hemi applying a force about 5X to your whole body, as compared to what the gun applies to your shoulder. All based on your shoulder knocked back an inch or two in maybe a hundredth of a second, while the Hemi takes your whole body a few hundred feet in, say, 5 seconds.

When your Cuda starts leaving bruises on your butt..THEN maybe you might have a point. You're right...That was sillier.:)

pacecil

06-20-2009, 08:24 PM

I'm not sure if you have "come around" or not. Your "action equal reaction" statement make me think you still think you get the same horsepower out of both ends of gun. (Vibe has explained why this is not true.) "Action" and "reaction" are names for FORCE not horsepower.

If you insist on thinking of recoil in terms of horsepower then you could if you wanted calculate the recoil horsepower of a 10 lb rifle firing our 200 gr bullet at 3000 fps. It's probably less than 125 hp. Does this seem reasonable to you?

If you insist on thinking of recoil in terms of horsepower then you could if you wanted calculate the recoil horsepower of a 10 lb rifle firing our 200 gr bullet at 3000 fps. It's probably less than 125 hp. Does this seem reasonable to you?

You may have hit upon the issue Pacecil. I had thought we had been using a 9lb rifle - which would have about a 15ft/sec recoil velocity - which would be 129 ft-lbs/sec of power..or 0.23HP. Notice how this is close to what Bill has been stating. I think he's been measuring the wrong end.

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