Accidentally shot a plane with asp 20

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Glenroiland

Member
May 9, 2019
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N.Y., United States
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I have a small collection of Rc planes. My son bought me a cheap one that I love to fly on my property. Accidentally flew it into the top of an oak (I'm surrounded by woods). Tried to free it by revving the engines, tried to knock it free with my quad copter...then it hit me.



I used my range finder....25 yards. I should be able to hit the branch it rested on...I've never shot almost straight up before. First shot made me realize I needed to correct my Point of aim......I hit the fuselage!!! Once I corrected, I actually hit the small branch and severed it causing my plane to fall back down.



Thank you Diana! And can someone explain to me the range finder? It read I think 25 linear yards, but when I set it to AI, it gave me the angle (I think around 70 degrees, and read I think 10 yards....)
 
You is a bad man shooting down planes with that gun. ;^) Your plane according to gravity was only 10 yards away. You were 10 yards from the plane horizontally. The up and down yardage is not figured into that range as the projectile is not affected by gravity while traveling straight up or down in the same way as in a linear or horizontal direction. So your range finder subtracted the number of up or down yards from the equation to make things right with the world
 
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Without going into the trig;

When you shoot at high angles, gravity does not pull straight down on your pellet. That is to say, if you shot straight up, you pellet would have no drop. It would just slow down faster because gravity would be holding it back. But it could not possibly go right or left due to gravity.

The same is true when you shoot straight down. The pellet just slows down MORE SLOWLY because gravity is pulling it along, but there can't possibly be any drop.

Now by extension if you are shooting up or down at a 45 degree angle the pellet falls half as much due to gravity as it normally would. This is either because it is also falling faster or slower depending upon whether you are shooting up hill or down hill.

All of that means that when you are shooting at a 45 degree angle gravity only has half the effect upon your pellet that it does have when you are shooting flat along the earth's surface.

There are math formulas you can use to compute how much impact the gravity has on the pellet for any given elevation angle but your "smart" hardware will do that for you these days.

Let this rule sink in; Your pellet always strikes higher than it normally would whether you are shooting up hill or down hill.

HTH
 
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What Oldspook says with one correction: shooting at 45 degrees (up or down, does not matter) the effect of gravity changing the trajectory is 0.7 or 70% (not half) of the total distance travelled

Another way to look at this: when shooting at 45 degrees up, the pellet travels X distance from muzzle to target. (the total distance) The horizontal part of travel of the total distance is X times cosine 45 = 0.7 . So the pulling effect of gravity that changes the pellet trajectory downward (what is called "bullet drop" and we correct for with "elevation") is excerted over only 0.7 times the total distance traveled.

If shooting 60 degrees up/down the effect of gravity on bullet drop is 0.5 (horizontal is half the distance of total distance travelled (X cos 60)), and if shooting 90 degrees up the horizontal distance travelled is 0 and thus the effect of gravity on bullet drop is 0.








 
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You guys are all very helpful! After I shot and hit a few inches above my point of aim (hitting the plane and not the branch) I figured that out. I didn't expect you guys to answer! 

I ranged it around 25 yards. I felt like such an idiot when I heard it strike the fuselage. It took a few seconds for me to figure out why it hit so much higher than I expected. I then set the rangefinder to AI (haven't tried that mode yet), and it read 10 yards. I corrected my shot and it took 3 shots to ground the plane. One missed, and it took 2 to cut the branch (actually the branch "hinged" releasing its captive). I was trying to show how stupid I was by asking that question (guess I should have clarified my intention in it being rhetorical). Also, being new to the forum, I didn't know where to put this. Didn't fit into hunting, so by "focusing" on the rangefinder it put me in this subforum. Could probably have put it in general, etc, but my go to subforums are optics, springers, and hunting. So I put it here. Maybe a mod will move it? 

I've never really shot much above or much below horizontal to experience those effects. I've actually taken (and did well in) advanced calculus, linear algebra, phyics, and have a strong grasp of trig.....of course that was 1991. I just felt like such a fool when I hit the plane. I actually said to myself, "if I hit the plane, my wife's never gonna let it go. But I've been shooting so we'll that I absolutely WON'T hit it.". Then the first shot hits the plane. What a fool!



.....and, yes. The plane still lives to fly another day!!!!



You guys are great!
 
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I used to fly model rockets back in the day. I shot some limbs off to free them with a shotgun or .22 rifle depending on limb size. Recently I rescued a rocket I built for my grandchildren. I used the FX , cut the rubber nose cone cord, like a razor. The kids were amazed.
Click to expand...

I miss my model rocket days!!'. Would have paid to see the look in their eyes when you got the rocket down!
 
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What Oldspook says with one correction: shooting at 45 degrees (up or down, does not matter) the effect of gravity changing the trajectory is 0.7 or 70% (not half) of the total distance travelled

Another way to look at this: when shooting at 45 degrees up, the pellet travels X distance from muzzle to target. (the total distance) The horizontal part of travel of the total distance is X times cosine 45 = 0.7 . So the pulling effect of gravity that changes the pellet trajectory downward (what is called "bullet drop" and we correct for with "elevation") is excerted over only 0.7 times the total distance traveled.

If shooting 60 degrees up/down the effect of gravity on bullet drop is 0.5 (horizontal is half the distance of total distance travelled (X cos 60)), and if shooting 90 degrees up the horizontal distance travelled is 0 and thus the effect of gravity on bullet drop is 0.







Click to expand...

=) Darn it! Forgot that little detail. Need to brush up on my trig. =)
 
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With angles like that I always think of a fly rod with a half oz. weight at the tip. With the rod held horizontal the tip droops quite a bit. But as you move the rod tip upward the rod bends less and less. The same with pointing the rod/shooting downward.
Click to expand...


Very precise analogy, actually. Never thought of that one. =)

I really should read all the posts before I create a reply... that duplicates someone else's post. =(
 
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