Mid range trajectory

[swampthing]

With a point on of about 65yds or so, do you get a higher or lower "mid" range trajectory. Compared to a slower arrow.  Basically if you the hold "point" on at 1/2 of your actual "point on" distance does a faster bow give you less midrange elevation or does it lower it?

[McDave]

I'm not sure if I understand your question, so if I'm answering the wrong question, you might want to re-phrase it.

If you're shooting at a target that is half of your point on distance, you will be holding the point of the arrow below the spot you want to hit.  The faster the bow, the flatter the trajectory, so a slower bow would have a larger gap than a faster bow.

[swampthing]

Exactally, but I question the trajectory difference inside each bows "point on."
A faster bow has a further point on than a slower bow, correct, but, does the faster bows halfway point, {ie; mid range trajectory height in inches}
Shoot at the 1/2 way distance for the fast bow's point on, then do the same with the slower bow, which bow would have a lower midrange trajectory?

[swampthing]

I understand that you have to hold under your target at close range, so, a slow bow will require a higher hold than a slow bow, but doeas that slower bow lob the arrow higher to reach the target than a faster bow? Talking inside 40yds.

[moebow]

swampthing,  Interesting question, here is my take on it.

The slower arrow MAY have a marginally shorter point on distance but PO distance is more a function of your holding point on your face than arrow speed.

I think you must factor the time of flight of the arrow so a faster arrow will travel a given time to reach it's point on distance.  That is also the time that gravity is acting on the arrow.  A slower arrow though will travel the same amount of time to reach its point on distance.  That time for each arrow would be for the arrow to cross the line of sight (going up), arch through the air and drop back to the line of sight which would be at the point on distance.

So, each arrow will travel about the about the same distance above the line of sight then drop back to the line of sight.  The faster arrow will be somewhat farther down range than the slower arrow.

At mid range, which I believe is your question, both arrows will be a given distance above the line of sight.  If you put your arrow tip on the target at mid (half) range, and shoot, your arrow will hit above the point on which you held the arrow tip.  Measure that distance and you will know how high above the line of sight your arrow is when traveling to your real point on distance.  Said another way that will be the point of highest trajectory of the arrow above the line of sight.

If you are shooting the slower arrow at the faster arrow's point on distance the slower arrow will be substantially higher than the fast arrow.  You will be holding well above the target with the slower arrow.

As I said, interesting question and one that can pretty easily be experimented with and measured.  My math and physics major is 40+ years in the past and largely unused so some of the more current physics type out there may explain it better.  If you do the experiment, report back and let us know the results.    

   

[swampthing]

Ha Ha.  Oh boy to type your meanings.  If the half way points are the same then...
Point on at 70yds, mid range trajectory of +20" @ 35yds, so low hold on 10" @17.5yds. and again @52yds
Point on at 45yds, mid range trajectory of +20" @22.5yds, low hold on of 10" @11yds.

[BigCnyn]

I also found that the midway point is not a point per say, there is a distance that the arrow travels "flat" as in 1-2 yards, then begins to fall as momentum does .

[Rattus58]

Don't know how to help you here, but here is an article that Chuck Adams wrote on the subject.

 http://www.huntingclub.com/articles/articletype/articleview/articleid/10111/controlling-arrow-trajectory--how-to-calculate-distance-for-angled-shots

I can tell you that with my longbow, 30 yard trajectory is quite the rainbow. I used to shoot in my neighbors guava patch at stuff just to do it, and I can tell you that without accurate means to tabulate the destruction caused by it in a forest of iron branches, trajectory is easily a foot or more, probably much more actually on a 30 yard shot.

After reading Adams article, a simple tape on your riser should easily give you some means of measuring this if he is correct.

Much Aloha..  :cool:

[Rattus58]

Originally posted by BigCnyn:
I also found that the midway point is not a point per say, there is a distance that the arrow travels "flat" as in 1-2 yards, then begins to fall as momentum does .

Although it seems this way, an arrow never travels "flat". It is always being drawn towards the ground (gravity) and so we always have to point the arrow upwards in order to lob it to the target. This may not be the visual we see from the string maybe, but it is the dynamics of getting to the target. The rainbow...  

How much it gets lobbed is up to the speed of the arrow, but it is quite a loft regardless of bow.

When bullets are fired and you calculate the trajectory on some of the old tables, they talk about the midpoint trajectory, which in most shots is  roughly near half the distance to the target and is the highest point of the shot. Arrows have the same the basic  trajectory.

Much Aloha..  :cool:

[swampthing]

All right maybe this way will make sense.
At 20yds, a faster arrow will not be as "high" as the same arrow going slower, based on a similar straight away 30yd shot. I just used the point on system to explain the question of this.
  Boils down to this question; Does a faster arrow have less of a trajectory inside 40yds.
  1. An arrow that has a point on of 70yds, will be at it's highest arc at 35yds. Roughly 20" high.
  2. An arrow that has a point on of 40 yds will be at it's highest arc at 20yds. Roughly 20" high
  3. So everywhere in between the bow and 40yds the faster bow will be aimed low.
  4. Inside 40yds with the slow arrow you will also aim low, but the amount you aim low will be a lot less at 30-40yds than the faster arrow, as you are approaching your point on distance with the slow one.
  5. 20yd shots: fast arrow aim 10" low at 17-18yds, slow arrow aim 20" low at 20yds, huge dirrence there.
  6. time to do some more testing I must know how a 30yd point on arrow looks at 15-20, I bet it won't be 20" high.
 Sounds like in this example a slow arrow is better for ease of hunting shots, no huge aiming gaps out to 30-35yds or so.

[Don Stokes]

A faster arrow has a flatter trajectory than a slower arrow at the same range, no matter what distance they are shot. It's as simple as that. It's easy to overthink these things.

[Rattus58]

Originally posted by swampthing:
All right maybe this way will make sense.
At 20yds, a faster arrow will not be as "high" as the same arrow going slower, based on a similar straight away 30yd shot. I just used the point on system to explain the question of this.
  Boils down to this question; Does a faster arrow have less of a trajectory inside 40yds.
  1. An arrow that has a point on of 70yds, will be at it's highest arc at 35yds. Roughly 20" high.
  2. An arrow that has a point on of 40 yds will be at it's highest arc at 20yds. Roughly 20" high
  3. So everywhere in between the bow and 40yds the faster bow will be aimed low.
  4. Inside 40yds with the slow arrow you will also aim low, but the amount you aim low will be a lot less at 30-40yds than the faster arrow, as you are approaching your point on distance with the slow one.
  5. 20yd shots: fast arrow aim 10" low at 17-18yds, slow arrow aim 20" low at 20yds, huge dirrence there.
  6. time to do some more testing I must know how a 30yd point on arrow looks at 15-20, I bet it won't be 20" high.
 Sounds like in this example a slow arrow is better for ease of hunting shots, no huge aiming gaps out to 30-35yds or so.

Are you using sights on your bow? There is no experience like "show" business... remember that musical... "Mame".... or the soundtrac...?? Me either.. but I remember the song... and it applies to archery.... "there is no business like SHOW business, like any business I know"

and that means do it. Shoot at your longest effective range... come into 5 yards shoot again. Do the shots from 5 to 50 and "learn" what your bow does in real time.

As for midrange trajectory, I'm sure a valid comparison happens only with equal distances. Velocity determines trajectory, and all that goes into it, drag, coefficient, etc.

Two objects might have the same rise in trajectory over given distances. I'd hate to be the one trying to equate a 350 arrow trajectory with one of 170.

I'm supposing you've some time on your hands...  

[Stumpkiller]

Originally posted by Rattus58:
Are you using sights on your bow? There is no experience like "show" business... remember that musical... "Mame".... or the soundtrac...?? Me either.. but I remember the song... and it applies to archery.... "there is no business like SHOW business, like any business I know"

"Annie Get Your Gun"   That one I can help with.  ;-)

As far as trajectories?  I don't know.  My left arm does that and it ain't talking.  I know my more powerful bows have a further POA impact spot, but it's not something I use except to entertain non-traditional folks.

[Rattus58]

Originally posted by Stumpkiller:
 

Originally posted by Rattus58:
Are you using sights on your bow? There is no experience like "show" business... remember that musical... "Mame".... or the soundtrac...?? Me either.. but I remember the song... and it applies to archery.... "there is no business like SHOW business, like any business I know"

"Annie Get Your Gun"   That one I can help with.  ;-)

As far as trajectories?  I don't know.  My left arm does that and it ain't talking.  I know my more powerful bows have a further POA impact spot, but it's not something I use except to entertain non-traditional folks. [/b]

That's cuz you been in the "show business"...        

Aloha...  :cool:

[swampthing]

Just took a 850g shaft, went back 18yds and aimed point on, 3 shots approx. 15" high. Tried my 500g shaft and it was a lot higher. Went to 38yds and put the 850 P.On and it hit point on.
Seems that the slower shaft shoots flatter inside forty yards in relation to the amount of elevation necessary. Faster=flatter?  Never quite understood why we want 200fps for 40yds, That 850g is going approx 160 or so.

[jhansen]

Swamp,
If you are trying to prove that slower is better the answer is "No".  Let's say we were to mount two identical design bows in a pair of shooting machines and adjust both so that they would launch arrows perfectly level to the ground.  The arrows are identical in every way.  The difference is that one bow is 40#@28" and the other is 60#@28".  Now let's imagine we can trigger both shooting machines to release the arrows at exactly the same time.  Both arrows will fly downrange and strike the ground at exactly the same time.  The difference will be that the arrow from the 60# bow will be further downrange when it returns to terra firma.  Speed counts when it comes to trajectory.  To get the slower arrow to impact at the same point as the faster one we will have to tilt the machine back to elevate the tip of the arrow so that it departs on an upward trajectory which will increase its flight time and allow it to travel further downrange.

What I just described will be true unless we change one of the variables, arrow weight.  Remember I said that the arrows were identical?  If we use a 400 grain arrow in the 40# bow and a 600 grain arrow in the 60# and again launch them on a perfectly flat trajectory both will again hit the ground at the same time.  But this time they will be much closer together in terms of distance flown.  If we keep using heavier and heavier arrows in the 60# bow but keep the 400 grainers in the 40# bow, we will reach a point where the lighter bow is actually launching its arrow a greater distance.  Now we would have to begin to tilt the shooting machine of the heavier bow to make it keep up.

I hope all this made sense.  A faster arrow is always better in terms of trajectory because you don't have to compensate for drop as much over any reasonable range.  I won't get into the ultra-heavy arrow debate!

John

[swampthing]

What I am supposing is neither, nor is it any of the above. Lets say you bog your bow down with a heavy arrow. Say 14gpp. What I'm looking for is to get rid of the high arc in order to reach 30yds point on. Now, when you have accomplished that, it seems to me that the trajectory is less, TOO THAT DISTANCE. You never have a great up and down rainbow trajectory. You have adjusted the weight and speed of the arrow to shoot "practically" straight, from right off the bow, maybe 8" high at 15yds, but dead on at 30. Yeah a faster arrow will shoot with less of an "OVERALL" arc but when one is tuned up to shoot point-on @30 I think you angle of deflection/correction will be much less at the hunting ranges inbetween.

[Rattus58]

Originally posted by swampthing:
What I am supposing is neither, nor is it any of the above. Lets say you bog your bow down with a heavy arrow. Say 14gpp. What I'm looking for is to get rid of the high arc in order to reach 30yds point on. Now, when you have accomplished that, it seems to me that the trajectory is less, TOO THAT DISTANCE. You never have a great up and down rainbow trajectory. You have adjusted the weight and speed of the arrow to shoot "practically" straight, from right off the bow, maybe 8" high at 15yds, but dead on at 30. Yeah a faster arrow will shoot with less of an "OVERALL" arc but when one is tuned up to shoot point-on @30 I think you angle of deflection/correction will be much less at the hunting ranges inbetween.

I'm not sure I am following you. Your bow is going to have an arrow drop of X no matter what you do, so the slower the bow/arrow combination the higher the arc is going to be compared to a faster arrow, no matter what.

The arc is going to be what it is over 30 yards if you are going to be point on at that point. The only way to reduce the arc is speed up the arrow for 30 yards.

Aloha...  :cool:

[swampthing]

If you speed up the arrow you will increase your point-on, which will have you shooting even higher a the ranges in between.
     Again this is a test, and, empahasis is on using the arrow tip as a sight. If you speed the arrow up too much it will require you to "aim" low in order to hit intended target. An arrow that is heavy and slow that comes of the shelf will be pretty flat to about 25-30yds not much correction needed as there is no high upward lobbing arc to reach the short distance of 30yds.
So you just draw up point at the target, inside 30yds, and release.

[Don Stokes]

Does not compute, swampthing. Try actually shooting some arrows. Like I said earlier, it's easy to overthink these things.