I mentioned this in the other topic about tips and overlays and such. I did this because I was intent on proving that adding weight to the tips of the bow would have dramatic effects on arrow speed. Well, it didn't!
In fact it turned out to be pretty negligible.
I do know that adding an additional 1044 grains to the shaft weight would have dramatic effects on speed. So, maybe we worry too much about the weight of our tips. If speed is important it would behoove us to reduce the weight of the string. Especially at the nocking point.
So, here is the test I did. I got pictures too somewhere but can't find em.
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Bow Tip Weight. An experiment to determine the speed effect of adding weight to the tips of a bow.
Bow:
ASL 66” NTN
Slight string follow
44# @ 28”
This bow has no tip overlays and has pin nocks
Weight was progressively added to both bow tips and the arrow speed checked with a chronograph. The weight was added by taping quarters to the tips of the bow. Each quarter weighs approx 87 grains.
All shots are with the same arrow. The arrow weight is about 625 grains. I didn't weigh the specific arrow used but that is in the range of that set of arrows.
First, four shots with no weight to establish a base line
141.8
139.9
137.3
139.5
Avg 139.6
Next four shots were with one quarter taped to each tip of the bow, so 87 grains of additional tip weight.
137.2
139.8
139.6
138.2
Avg 138.2 Equals 1.4 fps slower than unweighted tips
That resulted in such a minor speed difference that I went next to three quarters on each tip for a total of 261 grains of added weight.
138.7
137.9
138.7
137.8
Avg 138.2 This is identical to the speed with only one quarter on each tip. This is probably explained by the statistical margin of error.
The next increment was four quarters on each tip for a total of 348 grains of added weight on each tip.
137.0
135.5
135.8
137.0
Avg 136.3 Now, we have arrived at a speed loss of 3.3 fps.
And finally, six quarters were added to each bow tip for a total weight of 522 grains of added weight on each tip. This is in excess of one ounce per tip with one ounce equaling 437.5 grains.
134.1
130.4
134.4
135.6
Avg 133.6 this is a total of 6 fps loss of speed with the 522 grains added to each tip.
Other questions:
what would be the rate of loss if a much lighter arrow were used?
What would be the results of the same experiment if done with a recurve and various arrow weights