Primitive Archer
Main Discussion Area => Bows => Topic started by: DC on April 26, 2018, 12:27:11 pm
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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 :D :D Can you see anything wrong? Any explanation for this?
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You are about 3 ft too close to the machine LOL.
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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.
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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.
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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
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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.
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DC, you didn't post a pic of your shooting by hand set up, does it look like this? >:D
In all seriousness, I have to point out to PD that Don may be shooting lower pound draws and lighter arrows than usual
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I wonder if that gal is single?
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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.
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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.
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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.
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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%
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That is extremely fast for that style bow and a 26" draw. What is the unbraced profile like?
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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.
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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 :(
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Nasr...They are a tool just like every other tool to be used to help improve design and tillering skills.I've never regretted owning one.
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yeah that is true but i think it would help with trying new things and seeing how it effects speed. I do agree it isn't necessary just think it would be something fun to have.
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Everyones' viewpoint does'nt have to be the same.To each his own.Just like bows don't have to be pretty to be outstanding performing wise.I for one am not influeneced by all the make up.It's hard for the naked eye to see 5 to 10 or even more fps difference especially if only shooting 20 yards or less,but the unmerciful extractor of truth can see the difference.
Look forward to seeing your new bow posted DC.
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yeah that is true but i think it would help with trying new things and seeing how it effects speed. I do agree it isn't necessary just think it would be something fun to have.
They can be really frustrating to use. You will get error message after error message if things aren't just so. I first bought a Chrony(brand). It seems to have a small sweet spot(about 3/4" wide). The cheaper Caldwell is easier to use. Upstate got a Caldwell with all the bells and whistles and I think it's better than mine. Maybe he has a comment or two. I don't think one is more accurate but ease of use actually becomes more important after about the 10th error mesage. :D
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I had mine checked against others of other bow clubs.
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caldwell chrono hmm gonna have to check it out.
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I've had good luck with this brand.Use outside on a sunny day gets me the best results.If not proper light nothing appears on the screen.Very little if any errors.It's been shot through by many other archers also.
Competition electronics Inc. made it.They are'nt cheap that's for sure.I'm not sure why DC is getting so many errors.I'd have to be there when he is shooting to diagnose I guess.
(https://i.imgur.com/a5ZjSrG.jpg)
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I'm sure the errors are me and my lousy shooting but there is definitely a difference between those two.
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I have the same one as you DC. I find the errors come in when you aren't shooting directly over the sensor, like when I'm focused on my draw and release and not where the arrow is going. If I shoot parallel to the chrono and over the sensor I don't get errors.
And I agree, those are some good numbers. You must be doing something right. Not leaving unnecessary tip mass has made the biggest difference for me outside of building the bow with less set, which I'm still trying to get better at :-\.
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Hopefully the machine will solve those problems for me. I just finished modifying the trigger, now it's as direct a copy of Del's as I can tell from pictures except it's bench mounted like Jan's. Now I just have to hang the lighting properly. Copying someone else's work gets you going right but always feels like cheating. :D
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... now it's as direct a copy of Del's as I can tell from pictures except it's bench mounted like Jan's...Copying someone else's work gets you going right but always feels like cheating. :D
Yeah, but I was copying someone else's .. but I just call it "research" ;)
Del
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I like to call it borrowing ;)
I think you just built your first cross bow...
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I have that same Chrony BowEd. Well, i did, I gave it to my buddy to use while i am on the road. But its a heck of a machine. Works great.
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I think you just built your first cross bow...
That's all it is, except for the chrono and adjustable draw length :D
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I think you just built your first cross bow...
That's all it is, except for the chrono and adjustable draw length :D
You are correct! You have built a BETTER crossbow!
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... now it's as direct a copy of Del's as I can tell from pictures except it's bench mounted like Jan's...Copying someone else's work gets you going right but always feels like cheating. :D
Yeah, but I was copying someone else's .. but I just call it "research" ;)
Del
Del, if you see this would you mind posting a picture or two of your bow saddle? I'm having a bit of trouble getting different bows to sit nicely. Just wondering how you did it.
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Nice shooting machine DC! Maybe I will borrow some tips of your machine, and make my own...
I have a caldwell chrono too and I'm kinda satisfied with it. The phone app is nice, because you can get lot of data with it and fast. It has some bugs with disconnecting cable though..
At first the chrono only displayed errors, so I had to send it for repairs. Now I got a new one and it works nicely. Last time I got some errors, but like you said, it depends a lot on how straight you shoot through.
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Strange thing. I put masking tape over the holes to keep dust off the lenses. Yesterday I was using it and took 3 shots which registered fine and then I started getting ERR3. I noticed that the tape was still on. Took it off and it works great. What I don't understand is how it worked for 3 shots with the tape over the holes. I do have bright lights, 100watts about 2' from the unit, but still---