Adding Trimmer Line to Arrow Experiment

cohunter14

cohunter14

Administrator
Jul 10, 2017
5,343
I decided to try adding some trimmer line to one of my arrows as an experiment and see what the results looked like. I figured I would share my results here with you all in case someone is considering this. My current setup:

Hoyt Nitrum 34
30.5\" Draw Length
64lbs
Gold Tip Hunter Pro 340 Arrows
30\" Arrow Length (29.5\" shaft)
100gr Broadheads
Avg Weight: 425gr

I added .095\" trimmer line to one of the arrows. This added almost exactly 50gr to the setup, making the arrow weigh 475gr. Here are the results after shooting multiple arrows through the chronograph:

Initial Velocity:
Standard Arrow: 287fps, 77.72 ft/lbs of Kinetic Energy
Heavier Arrow: 272fps, 78.02 ft/lbs of Kinetic Energy

At 20 Yards:
Standard Arrow: 278fps, 72.92 ft/lbs of KE
Heavier Arrow: 265fps, 74.05 ft/lbs of KE

At 30 Yards:
Standard Arrow: 274fps, 70.84 ft/lbs of KE
Heavier Arrow: 261fps, 71.84 ft/lbs of KE

It\'s pretty windy today, so I decided not to stretch it farther than this, but I think you can get a good idea of the results here.

I also did a comparison of the drop of each arrow at 30 yards. I used my 20 yard pin and shot multiple times with each arrow. On average, the heavier arrow dropped an extra 1.5\" at 30 yards, which is not a lot, but it certainly matters. I would like to do this test out to 40+ and see the results as well, but too windy today.
 
Based on these initial results, I\'m pretty much content to just keep the same arrow setup. The KE increase is so minor (1.5% or less) that I don\'t really see the advantage, especially since this would pop my knocks back every once in awhile upon impact. Not a huge deal, but having to adjust that each time I shoot the arrow would need to provide more of an advantage to be worth it. I think I would need to get my arrow weight over 500gr to see anything noticeably different, but I don\'t plan on doing that anytime soon since it would require new arrows. Thoughts?
 
Sounds like a lot of work for negligible gains! I agree it doesn\'t seem worth it.

I do like a heavy setup as well.

I was going to suggest going to a 125 head if you wanted some more weight but with your draw legnrth and arrow length you\'re right on the edge of being to weak spined.
 
\"Ucsdryder\" said:
Sounds like a lot of work for negligible gains! I agree it doesn\'t seem worth it.

I do like a heavy setup as well.

I was going to suggest going to a 125 head if you wanted some more weight but with your draw legnrth and arrow length you\'re right on the edge of being to weak spined.
Click to expand...
Exactly...I wish I would have gone with the 300\'s.
 
What\'s really interesting about this is if the speed decreases exponentially with weight, the kinetic energy would actually be lower at 525gr. By adding 50gr, I lost 15fps initially and 13fps at both 20 and 30 yards. If I do the same with a 525gr arrow, here are those numbers:

Initial Velocity: 257fps, 76.98 ft/lbs
20 Yards: 252fps, 74.02 ft/lbs
30 Yards: 248fps, 71.69 ft/lbs
 
Here\'s an interesting calculator I found that makes this interesting http://www.realtree.com/kinetic-energy-and-momentum-calculator

It calculates Kinetic Energy as well as Momentum. Although I don\'t gain much in KE by adding weight, I definitely get a gain in momentum. By adding 50gr to my current setup, I have 6% more momentum at 30 yards. What\'s interesting is to tinker with this and try to find the point where you start losing Kinetic Energy. For me, again assuming the arrow speed decreases exponentially with weight, that point is somewhere right around 500gr. At 500gr, I have a 2% increase in KE and a 9% increase in Momentum at 30 yards. Beyond that weight, I begin to lose KE.

Fun to mess around with, but does any of this actually matter??? :crazy: :lol: :lol: :lol:
 
Good stuff Derek.
I agree it prob doesnt matter.

I have found that dead elk dont really care about arrow weight, speed, KE.... :)
 
I chrony-ed my bow speed at various draw weight settings, various broadhead weights, and eventually, arrow length (I shortened them to reduce weight and buckling effect).

the changes all had linear changes in velocity and were easy to track. looking at the chart and KE data makes me giggle to read articles about \"using heavy arrows+broadheads for better penetration\".

see attached data.
 
agree that momentum is what you\'re trying to maintain, not KE. funny thing is, the average archers arrow has roughly the KE of a .22LR! Same not true on momentum.

adding the momentum calculation to my spreadsheet was fairly easy, so I did.

my \"peak\" momentum was 0.501 slug*ft/sec when I tested 125 gr heads, and was still shooting full length arrows.

once I trimmed the arrow length and switched to 100gr heads, my momentum dropped 6%, to 0.470 slug*ft/sec. For that trade off, I got an 8% increase in \"muzzle\" velocity.

all that said, I\'m not yet a killer of elk with a bow so my analysis is just that...... analysis. no terminal experience. I\'m 2 for 3 with a rifle. 0 for 5 in archery season (never cut a hair). sure hope to change that someday.
 
Thanks for the experiment Derek, I was planning on doing the same thing with my setup to see what affect the heavier arrow has on \"misjudged yardage\" at 40 yards. I was going to get my setup dead-on at 40 yards and then step back to 45 and shoot my \"lighter\" arrow with my 40 yard pin on the bulls-eye and then adjust my pin to the heavier arrow and do the same test and see just how much lower the \"heavy\" arrow is. Figure that should be a good real world hunting simulation. You step out and see a bull, don\'t have time to range him and mis-estimate him at 40 when he is really 45 - I want to know if that heavy arrow costs me that bull in that situation. If it doesn\'t, I\'ll probably go with the heavier arrow.

How many strands of weed whacker string did you put in your arrow? I\'ve read if you can fit 3 strands it will up your grains by close to 125.

--Mitch
 
All the times Ive mis-judged the distance on an elk I guessed too far and shot under... never shot over... just sayin\' :)
 
\"cnelk\" said:
All the times Ive mis-judged the distance on an elk I guessed too far and shot under... never shot over... just sayin\' :)
Click to expand...


???

If you guess to far wouldn\'t you shoot high?


I usually guess 10% short over 30 yards. My internal range finder must need calibrated :lol:
 
oops my bad communicating!
I meant to say when I miss-judged the distance, the ELK is further than I guessed.
Which in turn means a low shot
 
Brad - do you know what your complete arrow weighs? How many elk have you lost due to poor penetration? How many have you lost or missed because of misestimation on yardage? Trying to figure out where that balance is between penetration and trajectory for me personally.

--Mitch
 
\"Old School\" said:
How many strands of weed whacker string did you put in your arrow? I\'ve read if you can fit 3 strands it will up your grains by close to 125.
Click to expand...
Mitch, I don\'t think there is any way I could get more than one strand in my arrow shaft. It\'s a fairly skinny shaft though.
 
\"elky McElkerson\" said:
did your bow seem quieter with the heavier arrow?
Click to expand...
I forgot to mention this. I was hoping it would, but I didn\'t notice a difference at all. I even recorded a video of it so I could listen to the difference and I didn\'t notice anything. I was going to add the video to my results, but I didn\'t really want to upload it to youtube just to add it here as there\'s no real video image.
 
\"Old School\" said:
Trying to figure out where that balance is between penetration and trajectory for me personally.
Click to expand...
\"Ucsdryder\" said:
I think momentum is more important than Ke. You can get Hogg ke with a super fast light arrow.
Click to expand...
Yeah, trying to find the ideal balance is the toughest part I think. It would be nice if there was some sort of a baseline that you want to shoot for. That\'s why I figure max KE could be a good spot since it adds a bunch of momentum at that point. From that spot, momentum increases but KE decreases. But if max momentum was the goal, people would be flinging 700gr arrows at 100fps.
 
\"Old School\" said:
Brad - do you know what your complete arrow weighs? How many elk have you lost due to poor penetration? How many have you lost or missed because of misestimation on yardage? Trying to figure out where that balance is between penetration and trajectory for me personally.

--Mitch
Click to expand...


Brad - do you know what your complete arrow weighs? = 420grs

How many elk have you lost due to poor penetration? = 2 but that was due to shoulder blades

How many have you missed because of misestimation on yardage? = Too many to remember :)
 
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