How accurate is STU calculator

[screamin]

I have found if you match the bows chrono'd speed to the calculators arrow speed its usually witinh a couples lbs on spine. It does allow me to go with the stiffest arrow that it says will fly, which my bows like and this keeps me from wasting time trying different shafts. In any event, bare shaft to verify because its not perfect.

[Yellow Dog]

IMHO the key to using the spine chart is to know what the exact centershot measurement of the bow is. Otherwise your "mileage may vary".

[Night Wing]

I use the calculator program and the numbers put in for the things needed have to be accurate. Centershot is the key. I use aluminum arrows and the calculator will give me a pretty close tunable arrow. I then fine tune by adjusting brace height up or down and I found this is very important also. Most people don't adjust their brace height and this is what throws them off when using the calculator program. So in my opinion, at least for aluminum arrows, centershot and brace height are very important. Below is my complete setup for all three of my bows.

Blacktail TD Recurve: 66", 42# @ 30". BS: 14 StrDyna97. BrcHt: 7 1/4". NP: 5/8". Arrow: 32", 2212. PW: 185 Grains. AW: 528 Grains. GPP: 12.57

Blacktail TD Recurve: 66", 37# @ 30". BS: 13StrDyna97. BrcHt: 7 5/8". NP: 5/8". Arrow: 32", 2212. PW: 180 Grains. AW: 523 Grains. GPP: 14.13

Belcher Longhorn LB: 68", 41# @ 30". BS: 14StrDacron. BrcHt: 6 5/8". NP: 5/8". Arrow: 32", 2212. PW: 200 Grains. AW: 543 Grains. GPP: 13.24

[marsniper27]

Thanks for all the information guys i can't wait to start shooting and tuning,

[cbCrow]

I got my new Xcellerator 2 weeks ago and wanted to utilize an arrow that would give me the full potential of the bow. I looked at the calc. and found an arrow to fill the bill. To make sure I bareshafted and was amazed that they came within a 1/4" of shaft length with the calc. being the longest. With the projected foc they both were in .05% of each other(old method vs. calc), and on the speed within .47fps. I think I will trust Mr. Miller in the future.      

[wingnut]

I've found it to be very accurate in selecting shafts and pt weights for starting tuning.  And once you have an arrow setup and shooting perfect, go back in and find the dynamic spine for the arrow.  That is the "gold standard" for that bow going forward.

Mike

[cbCrow]

On my other post the speed was posted wrong it should read 3.47fps with the calc. showing faster speed than I read.

[Old York]

FWIW, for the record, Stu does use a shooting machine to derive  arrows velocities,
but his DSC program to find arrow spines is based on this:

"The equations that I developed to derive the dynamic
spine are totally based on empirical data of actual
human shooters (both me and many others)."

[Mint]

It was a lifesaver for me. I just couldn't get arrows to fly perfectly. I put my info in the calculator and the arrows came out underspined so I put in some 50gr brass inserts and they flew like darts. It has worked for me in both normal foc and efoc arrows. I love it but like said above you have to make sure you get your bows shelf cut right as well as your draw and actual bow weight.

[Smallwood]

It's been very accurate for me and any minor corrections were simply made with a change in brace height and nock height.