Allegiance Force Draw Curve (stop data added)
02-02-2005, 07:55 AM
#1
Thread Starter
Join Date: Nov 2004
Location: Ohio
Posts: 262
Allegiance Force Draw Curve (stop data added)
Graph of Allegiance Force Draw Curve
Last night I picked up my BowTech Allegiance VFT from my local shop. I ordered a 70 lb., 27 1/2" model on December 30th making it about 4 1/2 weeks to arrival. After some initial setup and shooting a few arrows I was shooting decent groups but realized it was going to take a little getting used to since I have shot the same bow for 12 years prior. When I arrived home I took some basic measurements with a tape measure and scale and found I was only getting about 69% let-off. The draw stop still had some adjustment so I moved it to the end of the slot and now had exactly 80% as advertised. Other measurements were:
Brace Height - 6 13/16" (specs. say 7")
Axle-to-Axle - 33 9/16" (specs. say 33 5/8")
Tiller - 9 7/8"
I then put the bow in my jig to gather the measurements for the force draw curve. The graph and respective data:
Notice that I measured an AMO draw length of 27 3/4" and this was a 27 1/2" model. Above I mentioned that I moved the draw stop to obtain 80% let-off and I am guessing that is where the additional 1/4" came from. I am going to move the draw stop to the other side of the slot and put it back on the jig to find out how much draw length adjustment is provided by the stop. I will also know how much let-off percentage is affected by changing the DL. It appears that I have more than 1/4" total adjustment that is advertised. I also want to try adjusting the stop to 27" and then twisting the cables to go from 69% back to 80" let-off. I will follow up with these results if anyone is interested.
From the graph you can see how the Binary cam builds rather quickly and then gradually tapers off. There has been much discussion on the "front loaded" draw of the binary cam and I was curious what it looked like. I will be borrowing a friends Mathews LX that is also 27 1/2" DL and will compare the shape of each curve. I would rather do a comparison of the Switchback but I don't have access to one and the LX is the same draw length and has the typical one cam feel where it wants to rip your arm off when you let down. I have also read that the LX is one of the most efficient bows ever produced so it will be interesting to compare them.
Speaking of efficiency, I calculated a dynamic efficiency for my Allegiance of 84.1%. I believe that anything over 80% with a 350 grain arrow is considered a great number but I have been out of archery for about 10 years and maybe someone else could provide some typical efficiencies for similar bows. I do know that the speeds obtained from the Allegiance at short draw lengths are something I have never seen before.
My buddy did not bring his LX to work today like he was supposed to so it will tomorrow or later before I can post the force draw curve comparison.
Edit: found a small error on the curve, edited post to show corrected curve
Last night I picked up my BowTech Allegiance VFT from my local shop. I ordered a 70 lb., 27 1/2" model on December 30th making it about 4 1/2 weeks to arrival. After some initial setup and shooting a few arrows I was shooting decent groups but realized it was going to take a little getting used to since I have shot the same bow for 12 years prior. When I arrived home I took some basic measurements with a tape measure and scale and found I was only getting about 69% let-off. The draw stop still had some adjustment so I moved it to the end of the slot and now had exactly 80% as advertised. Other measurements were:
Brace Height - 6 13/16" (specs. say 7")
Axle-to-Axle - 33 9/16" (specs. say 33 5/8")
Tiller - 9 7/8"
I then put the bow in my jig to gather the measurements for the force draw curve. The graph and respective data:
Notice that I measured an AMO draw length of 27 3/4" and this was a 27 1/2" model. Above I mentioned that I moved the draw stop to obtain 80% let-off and I am guessing that is where the additional 1/4" came from. I am going to move the draw stop to the other side of the slot and put it back on the jig to find out how much draw length adjustment is provided by the stop. I will also know how much let-off percentage is affected by changing the DL. It appears that I have more than 1/4" total adjustment that is advertised. I also want to try adjusting the stop to 27" and then twisting the cables to go from 69% back to 80" let-off. I will follow up with these results if anyone is interested.
From the graph you can see how the Binary cam builds rather quickly and then gradually tapers off. There has been much discussion on the "front loaded" draw of the binary cam and I was curious what it looked like. I will be borrowing a friends Mathews LX that is also 27 1/2" DL and will compare the shape of each curve. I would rather do a comparison of the Switchback but I don't have access to one and the LX is the same draw length and has the typical one cam feel where it wants to rip your arm off when you let down. I have also read that the LX is one of the most efficient bows ever produced so it will be interesting to compare them.
Speaking of efficiency, I calculated a dynamic efficiency for my Allegiance of 84.1%. I believe that anything over 80% with a 350 grain arrow is considered a great number but I have been out of archery for about 10 years and maybe someone else could provide some typical efficiencies for similar bows. I do know that the speeds obtained from the Allegiance at short draw lengths are something I have never seen before.
My buddy did not bring his LX to work today like he was supposed to so it will tomorrow or later before I can post the force draw curve comparison.
Edit: found a small error on the curve, edited post to show corrected curve
02-02-2005, 07:58 AM
#2
Thread Starter
Join Date: Nov 2004
Location: Ohio
Posts: 262
RE: Graph of Allegiance Force Draw Curve
Pic:
Thought I would add a pic of my Allegiance for those of you still waiting (muzzyman
). I don't plan on keeping the prong rest but put it on for the 2413's I am shooting indoors. I want to do some accuracy comparison testing of the Trophy Taker and Drop Zone. If they don't offer any accuracy improvement then maybe I will stick with the prong rest for aluminum's and a launcher arm for carbons. I have never used a drop away but am eager to conduct some testing. One thing I don't like in theory is the short overdraw that most drop away rests need. With my short DL I prefer not to shorten the span between nock and rest anymore than necessary. Maybe the 1 to 1 1/2" is not enough to make a difference but a few fractional factorial DOE's will determine that
.
Thought I would add a pic of my Allegiance for those of you still waiting (muzzyman
). I don't plan on keeping the prong rest but put it on for the 2413's I am shooting indoors. I want to do some accuracy comparison testing of the Trophy Taker and Drop Zone. If they don't offer any accuracy improvement then maybe I will stick with the prong rest for aluminum's and a launcher arm for carbons. I have never used a drop away but am eager to conduct some testing. One thing I don't like in theory is the short overdraw that most drop away rests need. With my short DL I prefer not to shorten the span between nock and rest anymore than necessary. Maybe the 1 to 1 1/2" is not enough to make a difference but a few fractional factorial DOE's will determine that.
Muzzy)
02-02-2005, 08:52 AM
#4
Nontypical Buck
Join Date: Feb 2003
Location: Heaven IA USA
Posts: 2,597
RE: Graph of Allegiance Force Draw Curve
Very nice work there Blodg, you would make even old Norb Mullaney proud.
Interesting numbers.
What did you say your Birth Certificate Number was for your Allegiance?
Thanks for all the effort.
Interesting numbers.
What did you say your Birth Certificate Number was for your Allegiance?
Thanks for all the effort.
02-02-2005, 09:35 AM
#5
Nontypical Buck
Join Date: Feb 2003
Location: Central PA
Posts: 2,299
RE: Graph of Allegiance Force Draw Curve
Ya know..........buckeye.......I wasn't gonna say anything on this post at first, but seeing how you are just so willing to jab me with a stick....I'll post.
The chart does look exactly as it feels IMO. You just have to shoot the thing to realize just how easy it is to draw. I like the cycle on it. Unfortunately, mine is somewhere, probably in peices yet in Oregon.[:@]
The chart does look exactly as it feels IMO. You just have to shoot the thing to realize just how easy it is to draw. I like the cycle on it. Unfortunately, mine is somewhere, probably in peices yet in Oregon.[:@]
02-02-2005, 09:39 AM
#6
Join Date: Dec 2003
Location: Kansas
Posts: 316
RE: Graph of Allegiance Force Draw Curve
Very nice work. I would be very curious to see comparison curves for other bows, using your same jig. Try for a Hoyt too, just to hit some of the more popular cam configurations. Great work.
This brings up another question I have. I shot the Old Glory this past Monday. It was marked at 29.5", my DL, but it felt a bit short, as no loop was installed, which I usually have. Anyway, from which post, 65% or 80%, setting is DL determined? I need to maintain 65% letoff to remain legal for hunting in OR, so how long do I need to get the bow?
Thanks,
John
This brings up another question I have. I shot the Old Glory this past Monday. It was marked at 29.5", my DL, but it felt a bit short, as no loop was installed, which I usually have. Anyway, from which post, 65% or 80%, setting is DL determined? I need to maintain 65% letoff to remain legal for hunting in OR, so how long do I need to get the bow?
Thanks,
John
02-02-2005, 10:42 AM
#9
Giant Nontypical
Join Date: Aug 2003
Location: The OH-IO
Posts: 7,103
RE: Graph of Allegiance Force Draw Curve
Ya know..........buckeye.......I wasn't gonna say anything on this post at first, but seeing how you are just so willing to jab me with a stick....I'll post.
When I cross the eastern Buckeye border its like going to another country!
[8D]All in gist fun of course!