Equinox arrow speed help... please??

[bowhunter1]

Here we freak'n go!!! i have been read'n and talking to people all over the dang place just because i need to know... I have the flemish string on my Equinox, I am shooting the fire bolts with the factory vanes and inserts, with a 125 gr slick trick (to make it really sharp on the end) !! I do not own a chronograph, in all the dang reading and talking i have done I (THINK) my arrow are moving at 336.67 fps Can someone say yep thats right , or no dumb ass you can't even add right please..

Thank you all very much for your in put...

[yooper_man]

I had the Equinox with the same strings and arrows you use, but with 150gr broadheads. I estimated approx 330 FPS. I am sure you are close, but yours is probably a little faster.

Andrew

[Cossack]

I'm thinking that a bit fast. My Equinox with 405 gr arrow and Flemish hit abound 427 (chroned). Guesstimates are just that, only way to be sure is to chron it.

[bowhunter1]

the total weight is 390gr... the broadhead is 125gr. and the firebolt is 265 grs. according to the Accessories Excalibur web site.

[strum]

i would say your not too far off but why are you guessing 336.67?
I mean guessing 330 or 335 maybe but you are talking decimals here wha
my exomax (same bow)with the same (firebolt) and a 150gr tip excal flemmish string chronoed at 321fps . im sure with the 25 gr lighter BH your using you are nearing 330fps
looking at my notes that was a 418 gr arrow and with a 397 gr arrow I was seeing 334fps

[yooper_man]

the total weight is 390gr... the broadhead is 125gr. and the firebolt is 265 grs. according to the Accessories Excalibur web site.

Yep, I bet you are at or a little above 330 FPS.

Andrew

[bowhunter1]

while i was doing the calculations the calculator kicked out the decimal point i just put that exact number in the post .. and the reason for all this craziness , was to figure out if spending the money on a 380 or the mysterious 405 would be worth it.. how much extra would i really be gaining for the money spent So i have spent a while splitting hairs and do as much fact finding as i possibly can for what it was worth

[yooper_man]

while i was doing the calculations the calculator kicked out the decimal point i just put that exact number in the post .. and the reason for all this craziness , was to figure out if spending the money on a 380 or the mysterious 405 would be worth it.. how much extra would i really be gaining for the money spent So i have spent a while splitting hairs and do as much fact finding as i possibly can for what it was worth

My decision to sell off my Equinox for a Matrix 355 was more for the compact size and lighter weight. I knew I didn't need anymore speed. I am very happy with my decision.

Andrew

[bowhunter1]

What was it about the 380 that made you move down to the 355 ?

[bowhunter1]

hummmm ok, i understand that.

[Deerstalker]

I guessestimate that my Equinox shoots about 325/330 FSEC but I don't really care and was wondering why you would be concerned with the exact speed. I use mine for hunting and I try and keep my shots to 35 yards or less. If you knew the exact speed of your CB how would that aid you? The Equinox will kill anything that you may want to hunt.

[Dash]

while i was doing the calculations the calculator kicked out the decimal point i just put that exact number in the post .. and the reason for all this craziness , was to figure out if spending the money on a 380 or the mysterious 405 would be worth it.. how much extra would i really be gaining for the money spent So i have spent a while splitting hairs and do as much fact finding as i possibly can for what it was worth

My decision to sell off my Equinox for a Matrix 355 was more for the compact size and lighter weight. I knew I didn't need anymore speed. I am very happy with my decision.

Andrew

X2

[bowhunter1]

Well deerstalker, i like to know exactly what my equipment is doing. i want it to go as fast as it can , with as much Ke as i can muster and exactly what trade off of speed for weight i need to do that. Also like i said in my previous post, i was comparing the 380, and my Equinox to see if the extra cost of the 380 was worth it. I enjoy tinkering and fine tuning the arrows and broadheads to what I think is the perfect combo ...

[Cherokeeson]

the total weight is 390gr... the broadhead is 125gr. and the firebolt is 265 grs. according to the Accessories Excalibur web site.

Your would be 40gr above recommended which translates into roughly a 8 fps loss,
My guess is right at 342 fps with 101ke.

http://www.huntamerica.com/phpforums/vi ... f=14&t=269

After a little algebra, it comes down to this:

s2=sqrt(w1/w2)*s1

where w1 is the weight of the arrow that has a speed of s1, and w2 is the new arrow weight and speed of s2.

So say your bow shoots a 350 grain arrow 300 fps, and you want to know how fast you bow might shoot a 450gr arrow:

The new speed, s2 = sqrt(350/450)*300 = 264.5 fps.

This equation assumes that your bow puts the same amount of energy into each arrow. Generally bows will put slightly more energy into heavier arrows, so the actual speed you get with a heavier arrow will probably be a little higher than this formula calculates. Bonus fps!

Unfortunately, if you're going to a lighter arrow the converse applies, and this formula will likely overestimate the speed a little.

Also there is the "5:1 Rule" here: http://www.excaliburcrossbow.com/phpBB2 ... 04#p469504

And another good read here: http://www.excaliburcrossbow.com/phpBB2 ... 83#p470683

[bowhunter1]

I really did not take in to account that a little more arrow weight would allow the arrow its self to absorb more of the bows energy, gaining a little speed, i did know the weight of the arrow would add of subtract ke.
thanks for the math formula .