Does fps actually mean more range?

Discussion in 'General Airsoft Discussion' started by not_an_noob, Mar 31, 2015.

  1. not_an_noob

    not_an_noob Member

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    San Francisco
    Before everybody starts verbally assaulting me for saying this, please hear me out. So everybody (not everybody but you know what I mean) says that fps doesn't mean more range, and that it's the hop up, barrel, BB weight, etc. that adds range to your gun. I disagree however. If you had two guns with the exact same hop up, barrel, BBs, etc., and one shot 300 fps and the other shot 400 fps, would the one that shot 400 fps not have more range? They would be falling at the same rate, but the 400 fps Gun would shoot farther before hitting the ground.

    A comparison would be baseball players throwing a baseball. If one player threw 50 mph and the other threw 70 mph, the guy throwing 70 mph would be able to throw much farther.

    The velocity has at least something to do with the range, right?
     
  2. damamabomb

    damamabomb Active Member

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    somerset
    The answer is yes and no. Just cause your fps is higher doesn't necessarily mean it will shoot farther, but assuming all other variables equal, higher fps does equal more range. The laws of physics dictate that because the force of gravity is constant and non-terminating, It will eventually overpower any impulse force. That being said, If that initial impulse is grater, it will take longer for the bb to reach the ground because the force of gravity is in terms of time (9.8 m/s^2 to be exact).

    Another way to think about it would be the myth proven fact that if you dropped a bullet, and fired a bullet horizontally at the same time, they would reach the ground at the same time. this is again due to the universal force of gravity on earth (and mass is independent of the equation so it could be a bowling ball dropped and a bb fired, it matters not.) So clearly the bullet fired went farther than the bullet dropped. But the part that fogs this ideal are two things: backspin and trajectory. Backspin obviously is representative of the hopup effect. trajectory: Ever fire your gun well above the target to get more range? Well, yeah.... physics. The closer to 45 degrees from the horizontal axis an object launched, the farther it goes. (But we're not barbarians lob-shooting on full auto to get extra range, we enjoy the skill involved in lining up a shot and shooting straight at it.

    So if you have two guns with identical components asides from the springs, the one shooting a higher velocity will shoot farther. However, if the gun shooting a lower velocity has a better hop setup, it will more than likely shoot farther (because the backspin causes a manipulation in the energy to more directly and efficiently fight the force of gravity.
     
    Last edited: Mar 31, 2015

  3. airsoftmaniacman

    airsoftmaniacman Active Member

    1,797
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    Baltimore
    TheLost made an incredible guide on this topic. It's the best beginner-friendly article I've ever seen in the past eight years.

    http://www.airsoftsociety.com/The-Airsoft-Newb-Files-FPS-vs-Range-Airsoft-Society.html

    Energy and momentum result in increased range. Not velocity by itself. Velocity is a component of both kinetic energy and momentum though.

    So does velocity matter? Technically, yes. Since KE = 1/2 MV^2 and momentum = mass x velocity, velocity clearly plays a role. However, it is the actual energy and momentum of the BB that provide it the extra range, not simply the velocity.

    Take two identical guns using perfect 0.20g BBs, but with one of them shooting 400 FPS while the other shoots 300 FPS with the given BB weight. If these guns are inside a vacuum, the gun shooting 400 FPS will theoretically shoot the BB further than the gun shooting 300 FPS. That is projectile motion. However, the minute we incorporate drag into our calculations, we greatly change the actual results.

    In physics, there exists a concept known as terminal velocity. Essentially, there is a maximum velocity an object of a specific mass can reach when undergoing free fall. This same concept also exists in a horizontal plane in addition to the vertical plane of terminal velocity. There is a drag force that prevents a BB of a particular mass from traveling faster than a specific speed. This means that if the BB travels faster than this "horizontal terminal velocity," drag will quickly decelerate the BB so that it reaches that "HTV." As a result, a BB traveling faster than its HTV will decelerate exponentially rather than linearly due to the increased drag forces acting on it.

    This exponential drag force essentially negates the added velocity of the faster BB by slowing it down quicker. This results in the 400 FPS 0.20g BB traveling only a few feet more than the 300 FPS 0.20g BB rather than the expected several dozen feet. Additionally, the increased drag force makes the BB more likely to deviate from an ideal trajectory, which decreases precision and increases spread (increased grouping size).

    This explanation does not account for the Magnus effect or the force of friction within the barrel that affects the rotational momentum of the BB, which adds even more variables to the equation. We will also ignore atmospheric conditions like temperature, air pressure, humidity, and other weather phenomena.

    The only way to overcome this HTV is to increase the energy and momentum of the object, independent of velocity. This means increasing the mass of the object, since an object with more mass will have greater energy and momentum (without needing to increase velocity and thus increase drag), and thus higher HTV (and terminal velocity). This is why heavier BBs are needed for longer ranges. I will also not go into the Magnus/Bernoulli effect and its relationship to this change in mass.

    As a result, an increase in momentum and energy will yield greater range, of which velocity is only one of the components.

    Although this is a topic for another discussion, increased mass will also yield better precision due to increased angular momentum and linear momentum.

    Stay in school and pay attention in physics. If you enjoy teching, you'll find that Newtonian physics and E&M are very applicable to the science behind airsofting.
     
    Last edited: Mar 31, 2015
    Combatant91 likes this.
  4. Str8Oper6n

    Str8Oper6n New Member Supporting Member

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    ^ Was gonna say that there was an article on the top of the front page, but you beat me to it. The article is great and easy to read.
     
  5. Blair

    Blair New Member

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    Chantilly
    You guys make this really complicated. FPS equals range when you have the proper bore and hop.
     
  6. theonlyBuster

    theonlyBuster Active Member Lifetime Supporter

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    S. Florida
    It's complicated because it simply is complicated. You're NOT going to pick up a high end barrel and hop-up chamber and instantly get great results. You're going to have to tinker, test, and tinker some more, and even then you may ONLY get mediocre results. On top of that a high velocity with the wrong set up is just as bad as a high velocity with the wrong BB.
    Your logic of trying to simplify this is very simple-minded for such an advanced matter.

    If it was that easy, nearly everyone would have the same identical set up and achieving 75yard accurate shots. It's just not as simple as you're attempting to make it.

    Velocity, range, and accuracy is a delicate dance with a few complexities.

    -mobile device-
     
  7. airsoftmaniacman

    airsoftmaniacman Active Member

    1,797
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    Baltimore

    That's because it is complicated.
     
  8. jungley

    jungley New Member

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    Boston
    Yes, obviously, increasing FPS of the same weight BB will increase range.

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    So, obviously you want to be shooting at the maximum FPS allowed by your field. But then you want to increase range even further and you're not allowed to do it by increasing FPS...so then it comes down to tweaking the hopup.