Rifle: A machine rated in horsepower

[MistWolf]

If something is moving, work is being done and it's generating horsepower. If you simply drop an object, as it's falling it's doing work. So yes, there is horsepower being generated by the bullet as it travels, although it is diminishing. Just like winding up a flywheel. You wind it up, let it spin and can use the motion to power things although no more horsepower is applied to the flywheel.

If foot/pound is potential energy of an object (which does NOT require motion or work) is pounds/feet what we get when it's moving?

 

[Vibe]

If something is moving, work is being done and it's generating horsepower.

As a statement, by itself, this is not true. If it is moving at a constant velocity, under no acceleration, it's energy is not changing, thus no work is being done.

If you simply drop an object, as it's falling it's doing work. So yes, there is horsepower being generated by the bullet as it travels, although it is diminishing. Just like winding up a flywheel. You wind it up, let it spin and can use the motion to power things although no more horsepower is applied to the flywheel.

Stored energy is not power. nor horsepower. In the case of the dropped bullet, you would be very hard pressed to measure the work done BY the bullet. It would be easier to measure the work done TO the bullet by the atmosphere by it's performance in air vs it's calculated performance in vacuum. However that is not the problem at hand. The problem under discussion is the work done BY the rifle. That work ends at the muzzle.

If foot/pound is potential energy of an object (which does NOT require motion or work) is pounds/feet what (do) we get when it's moving?

Pounds-feet of kinetic energy. Energy is measured in the same terms (or can be) no matter what the type. Likewise the CHANGE in energy is also measured in the same units.

In fact - in the case of a frictionless situation (M)ass*(g)ravity*(H)eight=(1/2)(M)ass*(V)elocity*(V)elocity
Both sides will be equal AND measured in the same units. A Mass (M) dropped from Height (H) will achieve Velocity (V) when dropped in a vacuum under the influence of gravity (g). But this only hold true under truly frictionless conditions, or when frictional losses can be assumed to be very small. A rapidly traveling bullet in normal atmosphere will drop from 3000fps to somewhere just above 1000fps in the first 1000 yards...and that's not even pointed up. There are just too many losses to consider the use of that as even a secondary gauge of the actual HP results or numbers.

 

[MistWolf]

You may want to take a look at this page
http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/Work/DefinitionWork.html

After a bit of research, I must say I have a clearer understanding of what Vibe is saying. As long as the bullet in flight or the spinning flywheel are not transferring their energy to anything, work is not being done. However, both have energy that can be transferred, thus measured as horsepower when energy is transferred.
http://id.mind.net/~zona/mstm/physics/mechanics/energy/work/work.html

 

[Vibe]

You may want to take a look at this page
http://www.ac.wwu.edu/~vawter/PhysicsNet/Topics/Work/DefinitionWork.html

It does talk about gravity doing work

I've seen it. In fact I've posted a link to it in this thread.

I still think a body in motion, such as a bullet in flight is a force, though it be small.

Not until you try to stop it.

Same for a flywheel. They are both a force and can cause a change if/when harnessed. Matter of fact, you can hook up a spinning flywheel to a dyno, measure the torque and calculate the horsepower.

Well I suppose you can measure the HP required to stop it in a certain time period, and derive the amount of stored energy based upon the HP required. But it only slightly has any bearing upon our rifle problem.

The power of a falling object can be harnessed to power something. A good example of this is the trebuchet

Which almost directly converts MgH into 1/2 MV^2

PS- I don't understand all the squiggly math symbols they're using on that page,

Indicates the integration of the Force Vector (F=Ma) with respect to the change in position (Differential Displacement Vector).

but I betcha someone could use them to give us a clearer picture on how much HP our 300 Mag generates

I wouldn't bet much on it...I've used it here and there are those who still argue about it. The 210grain slug, in the barrel for 0.00144 seconds, exiting at 3000 fps produces just over 5000 HP using that math. I've shown all of the math here, and explained the logic behind why it has to be that way...yet here I am 11 days and 11 or 12 pages later, still trying to convince those who will not believe the physics of it.

 

[MistWolf]

I was typing, posting and editing my last reply as I was thinking it out and Vibe quoted me while it was still formulating. My final edited post is as above. As you can see, I came to the conclusion Vibe was leading me to. If this causes any confusion to any following this thread, I apologize

 

[Vibe]

LOL. No worries MistWolf. I'm of the opinion that if that confuses anyone that has read the rest of the thread...well they were bound and determined to be confused anyway.

 

[MistWolf]

Vibe, it may not be so bad as you think. The 5000 HP may be the GROSS HP. The .156 or whatever the figure was may what's needed after overcoming all other HP eating forces, such as barrel friction

 

[Vibe]

Vibe, it may not be so bad as you think. The 5000 HP may be the GROSS HP. The .156 or whatever the figure was may what's needed after overcoming all other HP eating forces, such as barrel friction

How was it Winnie the Pooh put it?????


Oh yeah.

Oh Bother

I give up. You may continue your blissful life now.

 

[MistWolf]

*Shrugs* I just don't know how much HP is lost to friction in this case. Just something to think about, not to prove a point.

...and yes, I'm having a blissful life. My sons love me and are doing well and my new wife loves me too. (I think she may even like me!)

 

[Bill Wynne]

Let's agree to quit on a happy note

*Shrugs* I just don't know how much HP is lost to friction in this case. Just something to think about, not to prove a point.

...and yes, I'm having a blissful life. My sons love me and are doing well and my new wife loves me too. (I think she may even like me!)

Mr. MistWolf,

You also have me to agree with your .156 hp answer. With all you have going for you in your life with your family and now me, you would be greedy to ask for more.

As for me, I don't really care if the facts run all over the place, I have my own opinion and it is not changing. The force of 5,000 hp would make much more noise and kick a lot more but I won't tell Vibe or 4mesh because they are happy thinking they are right too.

Concho Bill

 

[speedpro]

mind boggling!

I remember when simplicity and happiness was a "cork gun"...

 

[Jetmugg]

Try this....

I haven't tried myself - but how's this for an exercise.

Calculate the HP of a single cylinder 4-stroke engine (i.e. Briggs and Stratton) during the "power" stroke only. Compare this value with the stated HP (from the manufacturer) of the same engine.

SteveM.

 

[longshooter]

If the 300 Mag. were fired, such that the bullet
was exiting the cartridge case and entering the barrel bore as the
fuel dragster was about 80 yards from the finish line, the bullet would reach
the finish line first.

This thing keeps running thru my mind. If the hp of the bullet were not substantial, how would it be able to close the distance on the dragster? I keep thinking hp to weight ratio. I can't shake this thought.

 

[Bill Wynne]

This thing keeps running thru my mind. If the hp of the bullet were not substantial, how would it be able to close the distance on the dragster? I keep thinking hp to weight ratio. I can't shake this thought.

It might make you feel better if it was just a .222 Remington with a 50 grain bullet.

Look at it this way, bullets are faster than dragsters. I find it amazing that the dragster does so well in the contest.

Concho Bill

 

[MistWolf]

Mr. MistWolf,
You also have me to agree with your .156 hp answer. With all you have going for you in your life with your family and now me, you would be greedy to ask for more.

Concho Bill

Thank you Mr. Bill, for helping me see things in their proper perspective. You are right, to ask for more would constitute greed and ingratitude on my part. I shall take my riches and my Briggs & Stratton rifle, and retire to a quiet life by the sea

 

[Rad Mrdal]

Mr. MistWolf,

You also have me to agree with your .156 hp answer. With all you have going for you in your life with your family and now me, you would be greedy to ask for more.

As for me, I don't really care if the facts run all over the place, I have my own opinion and it is not changing. The force of 5,000 hp would make much more noise and kick a lot more but I won't tell Vibe or 4mesh because they are happy thinking they are right too.

Concho Bill

Pal whatever the correct figure is, it's in the thousands of HP. You will do much better job if you try to limit yourself to the bullet barrel BR issues.Rad

 

[Rad Mrdal]

This is a math question with only 1 right answer.The correct answer was given along with the formula and was well explained.Anything else is a waste of time and more importantly it is wrong.
To put this into perspective run your dragsters engine for 0.001711 seconds and let us know how loud and powerful it sounded and how far the car went down the track.
Lynn

Champs, lets do it in simple figures. 300wm, 84gr Retumbo, 0.0017 sec.

1sec : 0.0017 = 588 firings per second

588 x 84gr of Retumbo = 49 392 gr

49 392 : 7000 gr = 7.056 pounds of Retumbo burned within one second.

Pal do you recon that would help to move your gragster? Rad

 

[Bill Wynne]

Champs, lets do it in simple figures. 300wm, 84gr Retumbo, 0.0017 sec.

1sec : 0.0017 = 588 firings per second

588 x 84gr of Retumbo = 49 392 gr

49 392 : 7000 gr = 7.056 pounds of Retumbo burned within one second.

Pal do you recon that would help to move your gragster? Rad

Well Pal, I don't know if that would move a dragster but I will bet you could stop one with just some of that firepower if you wanted to.

Concho Bill

 

[Rad Mrdal]

Pal, you need to understand what HP actually means. An engine will produce maximum HP at certain RPM. Regardless will it be running at these RPM for for 1 sec or 10hours. Theoretically if something like the .300wm is able to burn 3.5 pounds of fuel if it would run for a full 1 second it is obvious that the HP output will be in thousands of HP. Hypothetically in the theory if the dragster engine would used the gun powder as a fuel it would burn 4.33 sec x 3.5 pounds = 15.155 pounds of fuel for its 4.33 sec. record run. Rad

 

[Al Nyhus]

I'll say this..it's been fun reading this thread.

Now, as to this quote:

That HP rating is at one point in the engines operating range and is extremely brief.The car during its burnout and getting to the lights is not producing 5,000 horsepower.After 440 yards it is not producing very much power either even though it is still moving forward.It is only producing peak power for a few brief moments in its run right before it shifts and near the end of the run.It is still rated at 5,000 horsepower even if it runs at 5,000 hp for only a brief part of a second during its 4.33 second run.

Current nitromethane Top Fuel and Funny Car rigs make well in excess of 7,000 horsepower..closer to 8,000. They don't "shift" in the conventional sense as they don't have a transmission. They use a multi-stage clutch assembly (5-8 stages) that is electronically timed and aplies the clutch in stages as the car goes down the track. Because of this, the engines actually run at or near peak r.p.m. for most of the run...not just "for a few brief moments". NHRA requires these cars to be equipped with a rev limiter (made by MSD) so the crew chiefs adjust clutch engagement rates, fuel flow and dozens of other things to keep the engines operating just below where they will hit the rev limiter.

And since Englishtown of this season, NHRA has shortened the track length to 1000 ft. for the TF and FC classes. They don't race to 1320 ft (440 yds) at this time.

In the interest of not having the answer dummied down.