Shooting machine problems

[DC]

I finished(maybe) my shooting machine and mounted the chrono. I did 10 test shots at 24" draw and got consistent 101-102 fps. That was low I thought so I tried 26". 129 fps four shots in a row. Very consistent but I've shot this bow at 180 fps. My draw length is 26.5". To check I took the bow and chrono off the machine and shot very slowly and deliberately. Draw to 26" hold and release. I get 175fps? Here's a picture of my setup. The arrow is just sitting in the 26" draw position, I didn't want to stand in front of it Can you see anything wrong? Any explanation for this?

[Badger]

  You are about 3 ft too close to the machine LOL.

[PEARL DRUMS]

Id tend to agree with the machine numbers more than what you got by hand. 180 FPS at 26.5" is amazingly fast for your usual draw weight range. I've never made a 180 FPS bow.

[Badger]

  Your arrow should be sitting in front of your bow the full length and then your chrono should be in front of the arrow. So your chrono should be at least 3 ft in front of the bow. You are reading the arrow while it is still accelerating.

[DC]

  You are about 3 ft too close to the machine LOL.

I was trying to make the thing as storable as I can, I'll stretch it out. I wouldn't have thought the numbers would be so consistent if it was too close. I just saw your accelerating comment. That makes sense

[DC]

Id tend to agree with the machine numbers more than what you got by hand. 180 FPS at 26.5" is amazingly fast for your usual draw weight range. I've never made a 180 FPS bow.

I've fought with this since I started measuring speed. It always seems to fast for someone that's only been at this for a couple of years. I even bought a second chrono and it agrees with the old one. I try to measure my draw length carefully and don't snap shoot but those are the numbers I get. I'm kinda with you though, it wouldn't surprise me if someone came along and said,"You old fool, you're doing it all wrong." (Kind of a Foghorn Leghorn comment) but I think Steve has solved everything but the storage issue.

[willie]

DC,  you didn't post a pic of your shooting by hand set up, does it look like this?


In all seriousness, I have to point out to PD that Don may be shooting lower pound draws and lighter arrows than usual

[JWMALONE]

I wonder if that gal is single?

[Badger]

Id tend to agree with the machine numbers more than what you got by hand. 180 FPS at 26.5" is amazingly fast for your usual draw weight range. I've never made a 180 FPS bow.

I've fought with this since I started measuring speed. It always seems to fast for someone that's only been at this for a couple of years. I even bought a second chrono and it agrees with the old one. I try to measure my draw length carefully and don't snap shoot but those are the numbers I get. I'm kinda with you though, it wouldn't surprise me if someone came along and said,"You old fool, you're doing it all wrong." (Kind of a Foghorn Leghorn comment) but I think Steve has solved everything but the storage issue.

  DC, I think you are making pretty fast bows. It doesn't matter how long you have been at it. If you are following basic principles and getting low set you will have good numbers.  As for snap shooting. If you practice with your machine you will learn how to calibrate your shooting style to pretty well match your machine. You need to check it everyonce in a while but you can get it hined in pretty close. A little bit of a snap shoot is needed to match the machine because the machine has a perfect clean release.

[PEARL DRUMS]

Id like to think I make an Ok bow. I draw a solid 28" and most arrows are 480-520 grains. I have made bows from 38# up to near 65#. I wouldn't touch 180 with anything I have or have had.

[Nasr]

i would love to see the numbers you get once you adjust the machine right. And i agree cause once i seen the picture you posted my first thought was that chrono seems a bit close.

[DC]

Thanks Steve. Had a glitch with the lights got it straight now. 184 fps @ 26". Bow is 43@26 and I was using a 374 grain arrow. It was the only one within reach that will clip onto the string.

PS found a proper arrow and got 177 fps@ 10 gpp

PD your arrows are a lot heavier than mine,almost 20%

[Badger]

  That is extremely fast for that style bow and a 26" draw. What is the unbraced profile like?

[DC]

This one is Hard Maple backed Douglas Maple. 15 Degrees deflex in the handle and the limbs are reflexed enough to bring the tips back to flat. No recurves. I'll post it as soon as it gets a finish on it.

[Nasr]

that sir is very impressive and i can tell it is gonna be a pretty bow congrats. Also nice set up next thing for me is to buy a chrono so i can get in with these discussions i feel left out