Is it even possible to curve bullets as seen in the recent movie "Wanted"?

[WhataBohr]

At first I would say no, and that this is the same type of flawed logic that leads people to believe that when a ball is being swung in circular motion on a string, and that string is cut, that the ball will go in a an arc.

But instead it flies off tangential to the point at which it was cut.

 

But then someone pointed out to me that you can put english on a cue ball to make it spin. They then said that if you were to twist the gun so that the barrel was moving faster (in a curved motion) than the bullet inside the barrel (as most guns typically make their bullets spin as part of the design) the bullet would be essentally the same as a cue ball that was hit with an angular force or whatever, and that the bullet would curve.

 

If it was physically possible to spin the gun that fast, would the bullet curve? Or his logic fallacious in some way? I believe it is, but I can't think of how to put Newtons law into words to explain his error. Heck, I may be wrong.

 

What do you all think?

 

 

 

In a local frame of reference, I would agree. However in the larger scale our universe is not quite that simple. Riemann Geometry it can be mathematically proven that parallel lines do intersect and straight lines are curves ones ( geodesics) hence the great theory of GR emerges. Physics locally is simple.

[GutZ]

If we were to account for that the whole question would change, no?

[ParanoiA]

That movie scene was probably the single dumbest thing I saw last year.

 

That scene, and then the rest of the movie. Geez, I had to sit through that entire pretentious garbage of a flick. Angelina Jolie, the ugliest model I think I've ever witnessed. The woman is a walking corpse...or a permanent heroine junkie...I can't figure which.

 

Sorry, I probly should have kept all that to myself.

[Severian]

Hmm... I wonder if making a bullet curve would make a good student project...

[iNow]

At least for those folks who always act up and/or cause problems in class, eh?

[jarema300]

Theoretically it would be possible to curve a BB by flicking your wrist as the BB would effectively roll up one side of the barrel giving it lateral spin hence making a low pressure side and high pressure side.

 

For example flicking your wrist to the right as you fired would curve the BB left.

 

At least I think it would work, could be tested with a high speed camera i suppose

[iNow]

The question is how much angle you can twist during the short time the projectile travels down the chamber.

 

So, with a bullet or BB... It's moving rather fast down the gun chamber, and for an exceedingly short time period before exiting. So, the bullet/BB is out of the chamber before your wrist has managed to curve the gun more than a degree or two.

 

On top of that, the projectile may stay oriented the same way even if the gun barrel curves around it... such as the gun twisting "around" the bullet, and the bullet is not effected.

 

Additionally, the surface of the projectile (bullet/BB) is generally too smooth for (if you managed somehow despite the above to impart any appreciable spin) ... for it to "grab" the air and curve (it's not like a threaded baseball, where the threads help it curve due to its rotation).

 

 

So no... On practically every single conceivable front, the idea is just silly and nonsensical.

[MM6]

Curving bullets..... two things.. during 2nd world war I believe, they actually made curved barrels to fire around corners

 

This makes no sense. The bullet will exit the barrel and continue in a straight path like any normal gun. Unless you mean when fired the barrel of the gun extends beyond the corner of the building/structure. That's the only way it would work.

 

It wouldn't make an arc in the air.

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There are microscopic imperfections on the surface of a bullet/BB. But as iNow said, they're too insignificant to allow any appreciable break in the bullet's flight.

[Mag]

This makes no sense. The bullet will exit the barrel and continue in a straight path like any normal gun. Unless you mean when fired the barrel of the gun extends beyond the corner of the building/structure. That's the only way it would work.

 

yup, that's what he means

 

http://www.patriotfiles.com/forum/imgcache/1562.png

 

some were even more curved

 

but as I said, they typically shattered/fractured the bullets.

[Severian]

This makes no sense. The bullet will exit the barrel and continue in a straight path like any normal gun.

 

Go read up on the Bernoulli Effect or the Magnus Effect and think what might happen if the bullet is spinning (the Magnus Effect article even has a section on spinning bullets).

[Megabrain]

I think you would have to produce a spherical missile then introduce spin to it, the friction would then be different on each side and thus the trajectory might be curved.

THe type of gun required is called a Musket, however when we had muskets we complained that we wanted the projectile to travel in a straight line - There's no pleasing some people...

[brockw69]

Mythbusters experimented with this exact topic based on that movie and they proved the myth busted, in other words it wouldn't work and didn't work in their experiments. It may be possible mathematically but not practically.

[J.C.MacSwell]

despite the fact that the bullet curves anyway due to gravity and the Coriolis Effect, i would have to say that on pure kinetic force from a human being, a bullets trajectory cannot be altered when fired from a gun.

If I am free to choose any non inertial frame of reference...I can make it appear to curve any way you like.

[Didymus]

A: they did an episode of this on myth busters. And you can.... If you bounce the bullet through a curved pipe.

 

B:he motion they show on the movie isn't a twisting motion like a curveball... What you said about it coming off on a tangent is correct. As shown, the bullet would go straight.

 

C: a bullet would fire straight in space. Doesn't "always" drop due to gravity.

 

D: on earth, a bullet could curve if it were completely redesigned to be in the shape of a disk. If the bullet's angular momentum were significant enough relative to it's forward momentum, it could act as a frisbee or boomerang and curve.

 

...so yes. It's possible. Just not with "real bullets" and not like they show on the movie. It has to spin end over end. Airplane terms, think massive yaw rather than roll. Like throwing a playing card.

[decraig]

http://en.wikipedia.org/wiki/Smart_bullet#Changing_trajectory

[imatfaal]

!

Moderator Note

 

Please don't post bare links. Members should be able to follow the line of an argument without going off-site. Thanks

 

[Integza]

It's possible, but not easy.

 

You would have to use round bullets and have a gun capable of shooting the bullet (giving it a linear velocity) and spinning that bullet at a very fast velocity (angular velocity ), because of The Magnus effect the bullet would make the bullet curve into the direction of the spinning.

 

For better understanding of the Magnus effect, watch this video:

 

https://www.youtube.com/watch?v=t7MsYZgtXXo

 

 

advertising links deleted

[JimDB]

I found a random youtube channel a while ago where they replace buck shot with random objects and see how they fire and how accurate they are. Im certain I seen curving on irregular objects. Imagine a bullet made up of two different materials with one half being heavier than the other. If you shot it from a rifled barrel it would spin (and destroy the barrel probably) but once it left the barrel it would begin to spin on a different axis and start curving. Well I think so anyway.

[DrP]

OK then - A BB gun with a smooth bore barrel which is roughened along one side of the inner tube (instead of riffling) - This would spin the BB as it exits and cause said spinach.

[iNow]

The Magnus effect is both real and very cool, but I'm unconvinced it would work with bullets given their velocities and relatively small surface area. Beyond evidence of the Magnus effect itself, is there any hard evidence of it working in any significant way on a bullet? If not, then I recommend we should maintain a degree of skepticism about this particular assertion until such empiricism supports it.

Edited August 31, 2015 by iNow

[Phi for All]

I agree with iNow. It's a big leap going from curve balls to shootout scenes from Wanted.

[Asimov]

Lanr12: Tech for self guided curving bullets is here and now. I assume some type of targeting is involved. Didnt see the movie.Some bullets can bend in flight with smart muscles.About $10,000/ bullet, not at discount stores yet.

 

Types of smart bullets[edit] Wikipedia

In 2008 the EXACTO program began under DARPA to develop a "fire and forget" smart sniper system including a guided smart bullet and improved scope. The exact technologies of this smart bullet have not been released. EXACTO was test fired in 2014 and results showing the bullet alter course to correct its path to its target were released.

In 2012 Sandia National Laboratories announced a self-guided bullet prototype that could track a target illuminated with a laser designator. The bullet is capable of updating its position 30 times a second and hitting targets over a mile away.^[2]

[iNow]

Fascinating. Here's a link to the citation: https://share.sandia.gov/news/resources/news_releases/bullet/

 

Looks like the adjustments currently possible are tiny, and nothing like the curves being asked about in the OP, but interesting all the same.

 

The four-inch-long bullet has actuators that steer tiny fins that guide it to its target.

<snip>

Sandia’s design for the four-inch-long bullet includes an optical sensor in the nose to detect a laser beam on a target. The sensor sends information to guidance and control electronics that use an algorithm in an eight-bit central processing unit to command electromagnetic actuators. These actuators steer tiny fins that guide the bullet to the target.

<snip>

Computer simulations showed an unguided bullet under real-world conditions could miss a target more than a half mile away (1,000 meters away) by 9.8 yards (9 meters), but a guided bullet would get within 8 inches (0.2 meters), according to the patent.

 

Plastic sabots provide a gas seal in the cartridge and protect the delicate fins until they drop off after the bullet emerges from the firearm’s barrel.