Announcement

Collapse
No announcement yet.

Interesting Observation

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    #16
    Originally posted by sir shovelhands View Post
    Maaaan that's some weight; are you slaying dragons with that ballista?
    Haha no dragons.

    I was testing efficiency of the bow

    Comment


      #17
      Originally posted by TENRMORE View Post
      Why would you use a heavier arrow to go elk hunting?

      Usually Kinetic energy is lost with an heavier arrow?

      Look at it this way: would it be easier to stop a finishing nail at 400 fps or a railroad spike at 300 fps?

      Just a thought...
      Yeah as mentioned you might need to rethink this. Trad guys have it figured out and have been for years. Heavy arrows with high FOC generate more momentum and therefore perform very well at low velocities. I came around to the idea that velocity is not something I'm even remotely concerned about. There are no true benefits, IMO to slinging a light arrow at game. Is it faster...yes, is it faster than the speed of sound...no. Therefore, the game can still hear the shot and possibly duck the string. Heavy arrows absorb more of the bows energy therefore the shot is quieter, high FOC arrows typically tune better with fixed blades, and then there is the momentum factor that allows the arrows weight to aid in the penetration.

      Comment


        #18
        Originally posted by TENRMORE View Post
        Why would you use a heavier arrow to go elk hunting?

        Usually Kinetic energy is lost with an heavier arrow?

        Look at it this way: would it be easier to stop a finishing nail at 400 fps or a railroad spike at 300 fps?

        Just a thought...
        I can tell you this, I would much rather get hit with a 400 fps finishing nail then a 300 fps railroad spike. That finishing nail might stop if it hits a major bone but that railroad spike is going to shatter it and keep going.

        Comment


          #19
          I'm by no means an archery expert, but weight has nothing to do with gravity. Two objects of different weights will drop at the same rate (not factoring in wind). The only way for a heavier/slower arrow to hit higher than a lighter/faster arrow is because the heavier arrow retained speed better.

          Think of it like this, you drop both arrows and they hit the ground at the same time. Lets say it takes 1 second. Even when the arrows are shot (assuming they are shot level) they will still both hit the ground in 1 second (unless there is some form of lift from the vanes, which I doubt there is). So the arrow that travels farther in that 1 second will have a shallower trajectory. If the heavier arrow retains speed better than the lighter arrow, it very well could have a flatter trajectory.

          This is thinking of it in terms of bullet ballistics, but it should be a close approximation.

          Comment


            #20
            Originally posted by bowhuntntxn View Post
            I would like to see the math on how a heavier objects resists a constant force like gravity. Seems impossible.

            Don't ge me wrong, because im not saying it didn't happen, but mathematically it shouldn't.
            I think it's called "momentum".

            Comment


              #21
              Originally posted by TENRMORE View Post
              Why would you use a heavier arrow to go elk hunting?

              Usually Kinetic energy is lost with an heavier arrow?

              Look at it this way: would it be easier to stop a finishing nail at 400 fps or a railroad spike at 300 fps?

              Just a thought...
              Finishing nail:
              50 grains @ 400 FPS = 0.0887 slugs (momentum) & 17.75 Ke

              Railroad spike:
              7000 grains @ 300 FPS = 9.317 slugs (momentum) & 1397.52 Ke

              Definitely easier to stop a finishing nail at these numbers (momentum).

              Comment


                #22
                Originally posted by JustinJ View Post
                I'm by no means an archery expert, but weight has nothing to do with gravity. Two objects of different weights will drop at the same rate (not factoring in wind). The only way for a heavier/slower arrow to hit higher than a lighter/faster arrow is because the heavier arrow retained speed better.

                Think of it like this, you drop both arrows and they hit the ground at the same time. Lets say it takes 1 second. Even when the arrows are shot (assuming they are shot level) they will still both hit the ground in 1 second (unless there is some form of lift from the vanes, which I doubt there is). So the arrow that travels farther in that 1 second will have a shallower trajectory. If the heavier arrow retains speed better than the lighter arrow, it very well could have a flatter trajectory.

                This is thinking of it in terms of bullet ballistics, but it should be a close approximation.
                A very good approximation.

                Back when I was debating the use of vanes over feathers the consensus was that feathers were faster out of the hole than vanes, but that vanes caught up in speed at about 30 yards.

                Even though we are talking about weight vs. drag (in my experiment) the results would be the same, but opposite, as Canny. IOW, the close range pins would move up and the long range pins would stay the same if we started with vanes for sighting in (which I did).

                What I found was pretty close to what everyone believed, and well within the margin of error for different bows. IIRC the difference in the two up close was a mere 12(ish) FPS and the vanes caught up in about 35 yards.

                The vanes, even though they were heavier, retained their speed better (due to less drag) than the feathers resulting in a flatter trajectory. Not by much, but it was there; mathematically anyway.

                So, in my experiment the heavier arrow (by about 15 gr) actually hit the same spot and the lighter arrow hit low at distance beyond 40 yards or so.

                It's not just about the weight. The arrow is a dynamic system in and of itself; everything must be considered and gravity isn't the only force acting on an arrow in flight.

                Comment


                  #23
                  llll

                  Comment


                    #24
                    Originally posted by Rat View Post
                    A very good approximation.

                    Back when I was debating the use of vanes over feathers the consensus was that feathers were faster out of the hole than vanes, but that vanes caught up in speed at about 30 yards.

                    Even though we are talking about weight vs. drag (in my experiment) the results would be the same, but opposite, as Canny. IOW, the close range pins would move up and the long range pins would stay the same if we started with vanes for sighting in (which I did).

                    What I found was pretty close to what everyone believed, and well within the margin of error for different bows. IIRC the difference in the two up close was a mere 12(ish) FPS and the vanes caught up in about 35 yards.

                    The vanes, even though they were heavier, retained their speed better (due to less drag) than the feathers resulting in a flatter trajectory. Not by much, but it was there; mathematically anyway.

                    So, in my experiment the heavier arrow (by about 15 gr) actually hit the same spot and the lighter arrow hit low at distance beyond 40 yards or so.

                    It's not just about the weight. The arrow is a dynamic system in and of itself; everything must be considered and gravity isn't the only force acting on an arrow in flight.

                    i like that

                    Comment


                      #25
                      Originally posted by Rat View Post
                      Finishing nail:
                      50 grains @ 400 FPS = 0.0887 slugs (momentum) & 17.75 Ke

                      Railroad spike:
                      7000 grains @ 300 FPS = 9.317 slugs (momentum) & 1397.52 Ke

                      Definitely easier to stop a finishing nail at these numbers (momentum).
                      FYI, slugs are not a unit of momentum, they're a unit of mass. Momentum units are slug*ft/s or kg*m/s.

                      Comment


                        #26
                        if you put your bow in a hooter shooter and aim it at the same spot the heavier arrow will shoot lower every time at every range. there is really no valid argument assuming fundamental equivalence of the arrows other than weight.

                        heavier arrows will retain a % of initial speed downrange better than a lighter arrow but they start slower so still will drop more by comparison with a lighter arrow at any range.
                        Last edited by Tom; 05-03-2018, 09:59 PM.

                        Comment


                          #27
                          Originally posted by sir shovelhands View Post
                          FYI, slugs are not a unit of momentum, they're a unit of mass. Momentum units are slug*ft/s or kg*m/s.
                          yes I'm sure rat knows its slug-ft/s

                          Comment


                            #28
                            Originally posted by enewman View Post
                            yes I'm sure rat knows its slug-ft/s
                            Slugs, lbm, and lbf is a great example of why imperial units are terrible.

                            Comment


                              #29
                              Originally posted by Tom View Post
                              if you put your bow in a hooter shooter and aim it at the same spot the heavier arrow will shoot lower every time at every range. there is really no valid argument assuming fundamental equivalence of the arrows other than weight.

                              heavier arrows will retain a % of initial speed downrange better than a lighter arrow but they start slower so still will drop more by comparison with a lighter arrow at any range.
                              That's funny cause this past weekend I was shooting with my step-dad. His bow is tuned to his light 380g Gold Tip arrow (very similar OD as my CE Maxima Reds) and when I let him shoot my heavy 495g arrows they were all in the same group. No statistical difference in elevation at 20 yards.

                              How does that fit into your statement about heavier arrows shooting lower every time at EVERY range?

                              Comment


                                #30
                                Originally posted by Tom View Post
                                if you put your bow in a hooter shooter and aim it at the same spot the heavier arrow will shoot lower every time at every range. there is really no valid argument assuming fundamental equivalence of the arrows other than weight.

                                heavier arrows will retain a % of initial speed downrange better than a lighter arrow but they start slower so still will drop more by comparison with a lighter arrow at any range.
                                Not so.

                                If I build two identical arrows in weight, but one has flu-flu vanes, the flu-flu arrow will not hit the same spot.

                                The increased drag from the flu-flu vanes will cause the arrow to slow down much faster.

                                Weight isn't everything...

                                Comment

                                Working...
                                X