Arrow weight vs force draw curve

[Selfbowman]

So I don’t high Jack the other thread I’ll ask question here. I’ve noticed that shooting to light a  flight arrow I guess that drag  takes over and the arrow just dies as it comes out of the bow. If to heavy I guess gravity takes over. So by doing your math thing with numbers in your  force draw some how compute the ideal mass or arrow weight. And yes I know mass placement is huge in the arrow.

[Del the cat]

Not sure you can calculate it directly, or from the force/draw curve.
But by plotting arrow speed vs arrow mass for a selection of arrow weights you hopefully you'd be able to see the point at which going lighter doesn't pay off in terms of the energy the arrow is carrying. Mind that's another can of worms... do we need arrow momentum (mass x velocity) or kinetic energy 1/2 m x v squared.
This post shows from my blog what I mean.
Del
https://bowyersdiary.blogspot.com/2011/11/mass-velocity-and-energy.html

[mmattockx]

Arvin,

What you are asking is not just about arrow mass, it involves the aerodynamics of the projectile as well. To incorporate bow dynamics, arrow dynamics on release and the aerodynamic performance of the arrow all into one model is a massive project that would be equivalent to the research required for several PhD theses.

The one way I can think of to directly measure arrow performance in flight is using doppler radar to track the arrow in flight and measure/calculate its velocity along the flight path. This is how some bullet companies do research on bullet shapes and calculate the ballistic coefficients for their bullets. The problem there is gaining access to those facilities and if the systems they use will work properly with arrows instead of bullets.


Mark

[Selfbowman]

Thanks guys. The math went over my head but I sort of understood your explanation. So far I’ve just been going on arrow weight that has previously broke records. Arrow dynamics’s also plays a huge part along with spine. I’ve got some flight arrows of days gone by. We haven’t improved on there design much at all. These arrows are from the fifty’s I think.

[willie]

Arvin,

a massive project that would be equivalent to the research required for several PhD theses.

I think Mark is accurate about developing computations....
But perhaps there is a way to experiment with what you have to get useful info..

if one assumes an arrow dies fast because of excessive velocity loss before the arrow settles into stable flight, then observing initial velocity out of the bow and the velocity at some shorter range rather (than shooting for distance), might be a way to find which arrows work best out of your bows with your releases.

What is the longest shot you could take at your shop if you set up a range?
What kind of group can you shoot at that range?

[bassman211]

The Turks way back when, tapered there flight arrows both ends to the middle, with tiny fletching, and shot arrows in the 220 to 250 gr. range as I understand it, They used over draws in some cases on there bows, and would heat there bows before shooting for distance in some cases. Some recorded distances they shot were not in the realm of reality in my mind. I still can't conceive it in my mind, and have no clue of the math, and physics involved.

[Muskyman]

I really don’t have anything to add to this conversation but, I started wondering what the heck is force draw curve. Looked it up and how to calculate it and now I’m going to have to calculate it on one of my bows.    Well maybe I am.