From: shawn@ut-emx.uucp (Shawn Boyd)
Newsgroups: alt.archery
Subject: Re: compound problem
Date: 15 Sep 92 15:07:45 GMT
Organization: The University of Texas at Austin; Austin, Texas

In article <VADER.92Sep10205206@meryl.csd.uu.se> vader@meryl.csd.uu.se (]ke Eldberg) writes:
>Shawn, thanks for your further comments and attempts to help me with
>my tear problems!
>
>Today I tried manipulating the steel thread on which the arrow
>rests.  

[deletions...]

>I twisted this slightly, to
>fractions of a millimeter can mean a lot with this type of rest.

 Yes.  This is a hard lesson in archery.  It is certainly clear that
 a slight adjustment to the launch platform of any projectile can 
 make a tremendous amount of difference down range in that even a slight
 modification at the lauch end changing any angle will be magnified 
 greatly down range.  Although the ballistics of an arrow shot from a 
 "typical" bow are vastly different than from a modern firearm, many of 
 the basic principles still apply, and this is one of them.

>However, no amount of manipulation & twisting could make the
>right tear go away completely.

 Just don't adjust the front rest out of center shot position.

>Next, I raised the mechanism of the arrow rest in order to get
>a lower angle on the thread. Seen from the side, it was pointing
>about 60-70 degrees up, and the manual says it should be 45 degrees.
>I guess a lower angle will give it more flex:
>
>   <<<---arrow---<<<             <<<---arrow---<<<
>     x                             x
>     x                              x
>     x                               x
>     x                                x
>
>The situation to the left will give little or no flex, the one
>to the right will. Hope this is intelligible...
>This improved the situation slightly, but not enough.
>
>I then set the bow down to very light -- I have no gauge but it
>feels like 45# or so. This produced an absolutely clean hole in
>the paper from 2.5 meters. 

 Another strong indication of underspined arrows.

>I still get some arrows sticking out
>of the target at weird angles, which may indicate a fishtailing
>problem, but observers are unable to visually confirm this. 

 Try letting someone else shoot the bow.  Question: Do you actually 
 watch your arrows track a line down range?  The best observation point
 for watching for fishtailing and dolphining is from directly behind 
 the bow, but many archers actually blink when they shoot, and don't 
 track the arrow as it flies.  I can often see a bad wobble when I shoot
 which just doesn't appear in any obvious way to even a careful, ex-
 perienced observer standing to the side.

 This is especially true of small diameter, short arrows.  They're just 
 plain harder to watch.

 Move your paper stand down range by several metres and shoot a few arrows,
 mark the tears, and move it again by several metres and mark the tears.
 If the tear moves horizontally or diagonally as the arrow progresses down 
 range, then you know that you have a wobble (fishtail or dolphin) whether 
 you can see it or not.  Unfortunately the test test is inconclusive if 
 the tear doesn't move, simple because the arrow could have wobbled out of 
 and then back into the original tear position at both places on the paper.
 While this is not likely, it should be remembered simply because this test
 can produce a false negative for wobble.  It will not produce a false pos-
 itive.
 

>It's
>possible that these errors are caused by my sloppy shooting...
>
>I have not been able to do a powder test yet, because I haven't found
>a suitable powder and it has been _raining_ for several days.

 Try baby powder or talcum in a squeeze bottle if you can't find any 
 of the foot powder I described.  This "foot powder" idea is proposed by 
 Larry Wise in his excellent little manual called "Tuning Your Compound 
 Bow" and I've found it to work a bit more effectively than plain talcum
 because something in the foot powder makes it cling a little better to 
 the surfaces in question (it's just ever so slightly sticky).  It also 
 sticks to cables where as talcum does not.

>The bow makes a lot of noise. Someone said that this may be normal
>for Hoyts, others say that it can be dealt with by twisting the
>cables to tense or relax them. 

 Hoyt's aren't inherantly noisey.  Three things can help this.  Cat whiskers
 tied above and below the mid-string serving about 3/4's up and down the 
 string both above and below the serving.  I use four sets actually, two 
 high, two low, both sets tied together.  You can also use puffs for this.
 I prefer whiskers.  You can also try about three inches of muff on both 
 lengths of the cable where it crosses.  Also at the point where the limbs
 fork there is a spot where the cable might be slapping.  A little rubber 
 button on the cable at these points can eliminate this problem.

 A guy did once tell me that Hoyt rockers were designed in such a way as 
 to cause the limbs to slap the bottom of the limb pockets, but I can't 
 verify this in anyway, and would tend to discount it as hearsay. 

>I dont know if this has anything
>to do with the tear problem.

 Probably not, unless the noise is from string on slap guard at end-launch
 time.  If you're slapping your arm, rotate your bow arm out from the bow
 to eliminate this problem.  Rotate from your shoulder cuff, not your elbow.
 Forgive me if you've already eliminated this problem from your shooting 
 style.

>It seems strange that I should have to shoot the bow at such a low
>setting, considerably less than what the arrows are spined for.
>It is even stranger that *underspined* arrows would produce an
>error typical for overspined ones. Life is strange, sometimes...

 If the problem is fishtailing, as opposed to a wrong angled arrow flight,
 then the problem is more understandable.  Try the dynamic paper test method
 (namely moving the paper stand to see if the angle of the tear changes at 
 different ranges).  The size of your fletching might also be a factor in 
 that shorter fletches will result in slower arrow recovery.

>Next, I plan to do the powder test. I will also take your advice
>and get a stiffer arrow, to do a comparison.
>
>Thanks again for your assistance. Will get back with results.
>
>]ke

 Sure.  Best of luck.  Hope the rain lets up.

 Shawn


Newsgroups: alt.archery