OnTarget 2 Users
02-12-2008 | 07:52 PM
#11
Nontypical Buck
Joined: Oct 2005
Posts: 2,355
Likes: 0
From: Flushing Michigan
RE: OnTarget 2 Users
When I used On Target, I found that my "predicted speed" versus my chrono'd speed was identical with my 365 grain "speed" arrows, and I didn't need to change the performance meter at all to get these results.
However, with my 515 grain hunting arrows, On Target predicted a speed that was 18 fps faster than the actual chrono. This was from the same bow, same setup, same tune, same wt on the string, same day, same chrono. Granted the KE was higher, but that's just due to the weight of the arrow. The gap between predicted speed and actual speed was huge with the heavy arrows and non-existent with the light arrows. This is where the performance slider comes into play, I believe.
With the heavy arrows, I had to slide the performance meter way down the scale just to get the predicted speed down to match the chrono. When I did that, those heavy hunting arrows went from being perfectly spined to overspined (according to OnTarget). I believe the results. It makes perfectly good sense that a launch speed of 18 fps slower would change the spine requirement of my arrows.
I think I would have got the same results with On Target if I'd just changed the IBO speed to get the predicted speed to match my chrono'd speed. Instead of using my bows advertised IBO of 316, I would have put in 298 for the IBO speed. The arrows that spined perfectly at a 316 IBO would have been overspined if I changed the IBO to 298, correct?
My trial version has expired, or else I'd try it to verify.
However, with my 515 grain hunting arrows, On Target predicted a speed that was 18 fps faster than the actual chrono. This was from the same bow, same setup, same tune, same wt on the string, same day, same chrono. Granted the KE was higher, but that's just due to the weight of the arrow. The gap between predicted speed and actual speed was huge with the heavy arrows and non-existent with the light arrows. This is where the performance slider comes into play, I believe.
With the heavy arrows, I had to slide the performance meter way down the scale just to get the predicted speed down to match the chrono. When I did that, those heavy hunting arrows went from being perfectly spined to overspined (according to OnTarget). I believe the results. It makes perfectly good sense that a launch speed of 18 fps slower would change the spine requirement of my arrows.
I think I would have got the same results with On Target if I'd just changed the IBO speed to get the predicted speed to match my chrono'd speed. Instead of using my bows advertised IBO of 316, I would have put in 298 for the IBO speed. The arrows that spined perfectly at a 316 IBO would have been overspined if I changed the IBO to 298, correct?
My trial version has expired, or else I'd try it to verify.
02-12-2008 | 07:53 PM
#12
Thread Starter
Nontypical Buck
Joined: Feb 2007
Posts: 2,188
Likes: 0
From: Balt, MD (orig: J-town,PA) The bowels of Hell!!!
RE: OnTarget 2 Users
I think you are correct in your assumption. Also, something you said in there would cause reason for concern if not monitored when selecting arrows using the program. The arrow that was set-up by adjusting the IBO shoots well whether using FT's or BH's. I had some underspined arrows that shot BH's 6-8" left of my FT's. I believe that those arrows were cut based on moving the slider. I reread the previous post and at that time I was under the assumption that moving the slider was the correct action when in fact it probably caused my problem. Since then, I've learned a lot about how to use the program.
I've been playing around withOT2 since I got home and it seems like one of those things that can just get you into trouble like it did me. This weekend I'll be chronographing some more arrows from a different manufacturer to see how the actually velocity compares to what OT2 says using my current set-up as the baseline.
I probably should have asked for a better definition or why you would actually want to use it when I asked him about adjusting the IBO speed.
I've been playing around withOT2 since I got home and it seems like one of those things that can just get you into trouble like it did me. This weekend I'll be chronographing some more arrows from a different manufacturer to see how the actually velocity compares to what OT2 says using my current set-up as the baseline.
I probably should have asked for a better definition or why you would actually want to use it when I asked him about adjusting the IBO speed.
02-12-2008 | 07:58 PM
#13
Nontypical Buck
Joined: Aug 2006
Posts: 2,520
Likes: 0
From: Southern MD
RE: OnTarget 2 Users
ORIGINAL: gzg38b
I think I would have got the same results with On Target if I'd just changed the IBO speed to get the predicted speed to match my chrono'd speed. Instead of using my bows advertised IBO of 316, I would have put in 298 for the IBO speed. The arrows that spined perfectly at a 316 IBO would have been overspined if I changed the IBO to 298, correct?
My trial version has expired, or else I'd try it to verify.
I think I would have got the same results with On Target if I'd just changed the IBO speed to get the predicted speed to match my chrono'd speed. Instead of using my bows advertised IBO of 316, I would have put in 298 for the IBO speed. The arrows that spined perfectly at a 316 IBO would have been overspined if I changed the IBO to 298, correct?
My trial version has expired, or else I'd try it to verify.
02-12-2008 | 07:59 PM
#14
Thread Starter
Nontypical Buck
Joined: Feb 2007
Posts: 2,188
Likes: 0
From: Balt, MD (orig: J-town,PA) The bowels of Hell!!!
RE: OnTarget 2 Users
ORIGINAL: gzg38b
When I used On Target, I found that my "predicted speed" versus my chrono'd speed was identical with my 365 grain "speed" arrows, and I didn't need to change the performance meter at all to get these results.
However, with my 515 grain hunting arrows, On Target predicted a speed that was 18 fps faster than the actual chrono. This was from the same bow, same setup, same tune, same wt on the string, same day, same chrono. Granted the KE was higher, but that's just due to the weight of the arrow. The gap between predicted speed and actual speed was huge with the heavy arrows and non-existent with the light arrows. This is where the performance slider comes into play, I believe.
With the heavy arrows, I had to slide the performance meter way down the scale just to get the predicted speed down to match the chrono. When I did that, those heavy hunting arrows went from being perfectly spined to overspined (according to OnTarget). I believe the results. It makes perfectly good sense that a launch speed of 18 fps slower would change the spine requirement of my arrows.
I think I would have got the same results with On Target if I'd just changed the IBO speed to get the predicted speed to match my chrono'd speed. Instead of using my bows advertised IBO of 316, I would have put in 298 for the IBO speed. The arrows that spined perfectly at a 316 IBO would have been overspined if I changed the IBO to 298, correct?
My trial version has expired, or else I'd try it to verify.
When I used On Target, I found that my "predicted speed" versus my chrono'd speed was identical with my 365 grain "speed" arrows, and I didn't need to change the performance meter at all to get these results.
However, with my 515 grain hunting arrows, On Target predicted a speed that was 18 fps faster than the actual chrono. This was from the same bow, same setup, same tune, same wt on the string, same day, same chrono. Granted the KE was higher, but that's just due to the weight of the arrow. The gap between predicted speed and actual speed was huge with the heavy arrows and non-existent with the light arrows. This is where the performance slider comes into play, I believe.
With the heavy arrows, I had to slide the performance meter way down the scale just to get the predicted speed down to match the chrono. When I did that, those heavy hunting arrows went from being perfectly spined to overspined (according to OnTarget). I believe the results. It makes perfectly good sense that a launch speed of 18 fps slower would change the spine requirement of my arrows.
I think I would have got the same results with On Target if I'd just changed the IBO speed to get the predicted speed to match my chrono'd speed. Instead of using my bows advertised IBO of 316, I would have put in 298 for the IBO speed. The arrows that spined perfectly at a 316 IBO would have been overspined if I changed the IBO to 298, correct?
My trial version has expired, or else I'd try it to verify.
If you'd like I can run your setup with my OT2 to verify what you think? Just supply me with all the info and I'll run and post.
02-12-2008 | 08:28 PM
#15
Nontypical Buck
Joined: Oct 2005
Posts: 2,355
Likes: 0
From: Flushing Michigan
RE: OnTarget 2 Users
From the On Target website:
The bow performance slider can be used to change bow efficiency as it relates to the IBO/AMO velocity. Changing the slider will alter the the program calculation for arrow velocity. This allows the user to quickly synch the program to a calculated or chronographed arrow velocity. Altering the performance factor will also affect the way the program makes shaft selections on the Spine Match Tab. Using a higher performance factor will result in the program selecting stiffer shafts. A lower performance factor will result in weaker shafts being selected.
After reading this, it sound like the software engineers intended the performance slider to be used to synch the predicted velocity to the chrono'd velocity. And they also sound like they knew what they were doing by in turn allowing this to affect the spine match tab. This just makes intuitive sense to me that a higher arrow speed would require a stiffer shaft. That's consistent with what I know about archery and basic physics.
If your predicted vs actual speeds were off by more than say 15 fps, and the arrow spine didn't change at all by synching the program to your chrono, I would think something is wrong.
The bow performance slider can be used to change bow efficiency as it relates to the IBO/AMO velocity. Changing the slider will alter the the program calculation for arrow velocity. This allows the user to quickly synch the program to a calculated or chronographed arrow velocity. Altering the performance factor will also affect the way the program makes shaft selections on the Spine Match Tab. Using a higher performance factor will result in the program selecting stiffer shafts. A lower performance factor will result in weaker shafts being selected.
After reading this, it sound like the software engineers intended the performance slider to be used to synch the predicted velocity to the chrono'd velocity. And they also sound like they knew what they were doing by in turn allowing this to affect the spine match tab. This just makes intuitive sense to me that a higher arrow speed would require a stiffer shaft. That's consistent with what I know about archery and basic physics.
If your predicted vs actual speeds were off by more than say 15 fps, and the arrow spine didn't change at all by synching the program to your chrono, I would think something is wrong.
02-12-2008 | 09:24 PM
#16
Nontypical Buck
Joined: Oct 2005
Posts: 2,355
Likes: 0
From: Flushing Michigan
RE: OnTarget 2 Users
ORIGINAL: davepjr71
You are correct in what you have said and asked about in regards to adjusting the IBO in your last paragraph. However, it suprises me that the program was that far off. After I set up the program with known info and adjusted the IBO for that one setup I've been able to adjust my DW and use arrows from 370 gr to 460 gr and get accurate results from OT2. I believe the program takes into account the efficiency changes that happen with heavier arrows and DW adjustments. You are telling the program that your bow only shoots a certain speed with a certain arrow.
If you'd like I can run your setup with my OT2 to verify what you think? Just supply me with all the info and I'll run and post.
ORIGINAL: gzg38b
When I used On Target, I found that my "predicted speed" versus my chrono'd speed was identical with my 365 grain "speed" arrows, and I didn't need to change the performance meter at all to get these results.
However, with my 515 grain hunting arrows, On Target predicted a speed that was 18 fps faster than the actual chrono. This was from the same bow, same setup, same tune, same wt on the string, same day, same chrono. Granted the KE was higher, but that's just due to the weight of the arrow. The gap between predicted speed and actual speed was huge with the heavy arrows and non-existent with the light arrows. This is where the performance slider comes into play, I believe.
With the heavy arrows, I had to slide the performance meter way down the scale just to get the predicted speed down to match the chrono. When I did that, those heavy hunting arrows went from being perfectly spined to overspined (according to OnTarget). I believe the results. It makes perfectly good sense that a launch speed of 18 fps slower would change the spine requirement of my arrows.
I think I would have got the same results with On Target if I'd just changed the IBO speed to get the predicted speed to match my chrono'd speed. Instead of using my bows advertised IBO of 316, I would have put in 298 for the IBO speed. The arrows that spined perfectly at a 316 IBO would have been overspined if I changed the IBO to 298, correct?
My trial version has expired, or else I'd try it to verify.
When I used On Target, I found that my "predicted speed" versus my chrono'd speed was identical with my 365 grain "speed" arrows, and I didn't need to change the performance meter at all to get these results.
However, with my 515 grain hunting arrows, On Target predicted a speed that was 18 fps faster than the actual chrono. This was from the same bow, same setup, same tune, same wt on the string, same day, same chrono. Granted the KE was higher, but that's just due to the weight of the arrow. The gap between predicted speed and actual speed was huge with the heavy arrows and non-existent with the light arrows. This is where the performance slider comes into play, I believe.
With the heavy arrows, I had to slide the performance meter way down the scale just to get the predicted speed down to match the chrono. When I did that, those heavy hunting arrows went from being perfectly spined to overspined (according to OnTarget). I believe the results. It makes perfectly good sense that a launch speed of 18 fps slower would change the spine requirement of my arrows.
I think I would have got the same results with On Target if I'd just changed the IBO speed to get the predicted speed to match my chrono'd speed. Instead of using my bows advertised IBO of 316, I would have put in 298 for the IBO speed. The arrows that spined perfectly at a 316 IBO would have been overspined if I changed the IBO to 298, correct?
My trial version has expired, or else I'd try it to verify.
If you'd like I can run your setup with my OT2 to verify what you think? Just supply me with all the info and I'll run and post.
06 Pearson Stealth 316 IBO
70 lbs verified with scale ; 75% letoff
29.5" draw (AMO measured)
33.75" ATA (measured)
7.5" BH (measured)
Overdraw: 0
2 Cam Hard (not sure about what to call my hybrid cams)
CX Terminator Hunter 6075 cut at 28.5"
125 grain point
11 grain insert
FOB 24grains (be sure to type "1" for number of vanes)
5 grain wrap
Carbon Express TCX nock 8.7 grains
No bushing/pin (0 grains)
Total Arrow weight: 515.7
Peep 10 grains
D Loop 8 grains
Nock Point 2 grains
Silencers 20
Silencer DFC 0.0000
Release Box Checked
My actual chrono speed with this setup was 257 fps.
Actual Arrow weight (measured) was 515 grains.
The software predicted271.5 fps,much faster than 257 fps actually chrono'd.In order for me to "calibrate" to 257 fps, I had to slide the performance meter almost all the way to the left. After doing this, my arrows were showing overspined.
Are you able to duplicate my results?
The strange thing is that for a lighter arrow (just over 350 grains), my predicted matched my actual. Figure that one out LOL.
02-13-2008 | 04:38 AM
#18
Thread Starter
Nontypical Buck
Joined: Feb 2007
Posts: 2,188
Likes: 0
From: Balt, MD (orig: J-town,PA) The bowels of Hell!!!
RE: OnTarget 2 Users
According to the help section and Larry you shouldn't have to adjust the slider to get your correct velocity. With the same bow set-up your IBO would not change no matter what arrow you use. That's why I want to run your bow through and see this for myself.
I'll run it after work. Thanks for your info.
You are probably correct with your description of what DFC means. I'd guess it's in inches.
I'll run it after work. Thanks for your info.
You are probably correct with your description of what DFC means. I'd guess it's in inches.
02-13-2008 | 04:04 PM
#19
Nontypical Buck
Joined: Oct 2005
Posts: 2,355
Likes: 0
From: Flushing Michigan
RE: OnTarget 2 Users
I did some experimenting with On Target. For my setup, I varied arrow weight in 25 grain increments from 350 grains all the way up to 550 grains.For every 25 grains of arrow weight,the modelshowed a speed loss5.135 fps (for my setup). This shows that On Target uses a linear relationship for speed vs arrow weight.
Next, I plotted my known chronographed velocities for various arrow weights ranging from 341 grains to 515 grains. When you compare the two graphs, you see that my actual chronographed speeds also follow a linear relationship. However, the SLOPE is different. In reality, for every 25 grains of arrow weight, MY bow loses 7 fps.
That's the problem in a nutshell. The software assumes a speed loss of 5 fps for every 25 grains of arrow weight. My bow loses 7 fps for every 25 grains of arrow weight.
I don't know why my bow would perform this way. The cam timing is dead on, and the measure DL and DW are correct. For some reason, my bow just "likes" lighter arrows.
Next, I plotted my known chronographed velocities for various arrow weights ranging from 341 grains to 515 grains. When you compare the two graphs, you see that my actual chronographed speeds also follow a linear relationship. However, the SLOPE is different. In reality, for every 25 grains of arrow weight, MY bow loses 7 fps.
That's the problem in a nutshell. The software assumes a speed loss of 5 fps for every 25 grains of arrow weight. My bow loses 7 fps for every 25 grains of arrow weight.
I don't know why my bow would perform this way. The cam timing is dead on, and the measure DL and DW are correct. For some reason, my bow just "likes" lighter arrows.
02-13-2008 | 04:55 PM
#20
Thread Starter
Nontypical Buck
Joined: Feb 2007
Posts: 2,188
Likes: 0
From: Balt, MD (orig: J-town,PA) The bowels of Hell!!!
RE: OnTarget 2 Users
Here are both arrows with an adjusted IBO of 302. I adjusted the IBO for the 515.7 gr arrow and after getting the results then manually entered in a 365 gr weight for the arrow. What was the predicted speed that you got for the 365 gr arrow? The 289 fps for the 365 gr arrowseems reasonable with your DL and the "stock" IBO speed being 316.
For comparison,using the known settings for my bow I'd be at 265 w/ the 515.7 gr arrow. The Ally has a slightly higher factory IBO than your bow and I have a 30" DL. I got 296 fps out of my bow for the 365 gr arrow.
If the pictures are too small please provide me with an email addy and I'll send a file with all your info.
For comparison,using the known settings for my bow I'd be at 265 w/ the 515.7 gr arrow. The Ally has a slightly higher factory IBO than your bow and I have a 30" DL. I got 296 fps out of my bow for the 365 gr arrow.
If the pictures are too small please provide me with an email addy and I'll send a file with all your info.