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in reply to: Kingwouldbe & Tuffhead #45956
There’s that GORGEOUS fletching again. It looks SO FAMILAR. 😛
Next to a buffalo that’s about as good an animal as one can possibly get to test out a broadhead on. Keep up the good work King.
Ed
in reply to: 2 blade broadhead orientation #44885Howard said … VERTICAL!
Ed
Humm … not much centershot on that bow, is there.
in reply to: 2 blade broadhead orientation #44370cyberscout wrote: Mr Graf –
I was first told, 1969 — vertical to get thru ribs — straight fletch? [ thus no spiral ?]Scout, even with straight fletch the arrow rotates in flight, because of the pressure differential on the fletching.
During the Study’s testing I was often changing broadheads, and broadhead blade orientation was often at all sorts of angles. I find no practical differences in the orientation of the broadhead, as far as shooting or accuracy are concerned.
In theory there should be a difference in arrow flex during the initial phase of paradox (first bend and rebound around the riser) because of air pressure difference on the broadhead’s blade, with the vertical mounted head having more air resistance. However, the increased pressure works in opposing directions during the flex and the rebound. It’s very likely that these forces come very close to offsetting each other.
As a matter of preference, on my serious hunting arrows I mount the broadheads with the blades vertical.
Ed
in reply to: Tuffhead update #44342dwcphoto wrote: Doc,
One question I have is what type of quiver do you use? I’m using a side quiver with a foam bottom (safari tuff). Thanks, dwcDWC, For serious hunting I’m very partial to the CatQuiver. I’ve used that style for near fifty years, going all the way back to the St. Charles quiver (I still have it, too). Next to that I like a stalker type quiver. For other shooting I generally use a back quiver.
Ed
in reply to: Ultra EFOC results in Buffalo arrow #38841Troy, how was the trajectory of the 888 grain, Ultra-EFOC arrow, as compared to a similar weight hickory shaft?
Shooting some similarly heavy, tuned arrows that were IDENTICAL in every aspect except their degree of FOC (and a very slight difference in shaft length) I was seeing a marked difference in trajectory. One arrow was EFOC (27%) and one Normal FOC (12%).
I did the testing at 40 meters (about 44 yards) and the EFOC arrow was impacting (group center) 10 to 12 inches higher than the Normal FOC arrow. I was using a bit more poundage that you shoot and was wondering if you could notice any difference in trajectory with your lighter draw weight on that heavy an arrow.
Ed
in reply to: Ultra EFOC results in Buffalo arrow #38751See what you been missing, Troy? If you hadn’t moved out of the South I’d probably still been stopping by every year to fill you in on the latest research and tank up on all the questions and comments you always came up with, so I’d have new things to think about and test. I’ve sure missed those annual visit with both you and Rod.
Ed
in reply to: Ultra EFOC results in Buffalo arrow #38678Troy Breeding wrote: My current setup braeshafts great
Troy, I see you’re still trying to keep abreast of the subject. Your setup BRAeshafts great? I’ll bet it does!
That shift in the measured FOC is understandable. You moved more of the weight further forward, increasing the measured FOC. I use the shaft length to measure FOC, rather than overall arrow length, simply because it is the AMO standard measurement, and has been in use longer than the ‘overall arrow length method’. I’m doing a copy and paste from the Prologue to the 2007 Updates on your question about measure FOC that discusses FOC and the two measurement methods but, in a nutshell, either of the methods only provide us with a relative number, not the arrow’s true FOC.
From: Prologue to the 2007 Updates:
What’s the “correct way” to measure my arrow’s FOC? The AMO Standard FOC measurement uses shaft-length; ignoring insert, taper and tip (broadhead) length. The other commonly used formula employs the arrow’s overall length; including the insert, taper and tip. Which is “correct”? Neither. True FOC is based on the center of pressure. We merely simulate the CP location in both formulas. The AMO formula was adopted as ‘standard’ merely because, between the two commonly used formulas it uses a simulation point nearer the actual CP location for most commonly used target arrows during flight through air.
Just as it is with static spine, the FOC ‘number’ we use is definitive of absolutely nothing about our arrow’s flight. The commonly used static spine and FOC ‘numbers’ merely allow us to make a relative comparison of one arrow to another; nothing more. For example, static spine measures relative stiffness of a shaft; how much it flexes when a weight of specified mass is suspended mid-way between two shaft-supporting points; which are located a specified distance apart. Everything about the measurement is relative, not absolute.
Static spine tells you nothing at all about an arrow’s dynamic spine – how it will react when you shoot it off your individual bow. If you doubt that, perfectly tune an arrow from a true center-shot bow and then measure its static spine on your spine tester. Now take that same arrow and shoot it from a non-center-shot bow (one with a peg rest – no arrow shelf at all) of equal draw weight. What happens? The arrow will shoot massively strong-spine. The arrow hasn’t changed; the launch-force and power stroke are the same; and the shaft’s static spine hasn’t changed. However, the shaft’s dynamic spine is now no longer anywhere close to correct, and it no longer shoots where you’re aiming.
All static-spine indicates is the relative stiffness of the shaft. What it does do is provide you a reference point. This helps whenever you need to find a stiffer or softer spine in order to get your arrow to shoot well from your bow. This is all it does; nothing else. It merely allows you to compare shafts relative to each other, so you can tell which one is ‘stiffer’ and which one is ‘weaker’. Static spine’s ‘relativity’ is precisely why it’s necessary to tune your arrow to your bow in order to get correct arrow flight.
No static measurement or calculation contends with the myriad variables encountered when you shoot an arrow from your bow. This is why, besides charts, Easton publishes 35 instructional pages on selecting ‘the right arrow’ after you’ve used their ‘static-spine’ charts to find a ‘starting place’. No chart provides a magic number saying, “Pick me. I’m the right one!”
Commonly used FOC measurements are exactly the same; they are relative. Neither formula is “correct”, nor is either “wrong”. Each serves its purpose equally well; providing a reference point. As long as you know which formula was applied to a given arrow to determine its ‘relative FOC’, you can duplicate results. If you prefer, you can re-measure and state the arrow’s FOC in the other format; that’s perfectly alright. It still provides you a ‘relative reference’.
For practical applications, either commonly used FOC formula works equally well. Just remain aware that neither genuinely tells you anything at all that’s ‘precise’ about an arrow’s true FOC. However, for a given arrow design, when our ‘commonly measured’ FOC goes up the true FOC also goes up; but the amount we’ve ‘measured’ won’t indicate the actual amount of change in true FOC. The single most important thing to remember is that the ‘relative measurement’ method you use should always be stated, so everyone is “reading off the same page” when making comparisons, or trying to duplicate results.
Ed
in reply to: Ultra EFOC results in Buffalo arrow #38535Troy, that should make one heck of a buffalo arrow. Now all you need is more bull … buffalo. Did it kinda thump your target when it hit? Sounds like you might not need to build your arrow plate out after all.
When the tuning gets ‘close’ I shorten only 5mm at a time; about 1/5 inch. It’s sometimes amazing how much difference just that 5mm makes. 😯
Ed
in reply to: My Setup Adequate for Elk??? #37705cyberscout wrote:
dasher -dancer -prancer- vixen -comet -cupid -donner and Blitzen + rudolph — it is scary sometimes what one remembersScout, I’ll bet it was Gene Autry that made it impossible for you to forget those. That’s what did it for me, and you’ve got them in the correct order too!
Ed
in reply to: Point of deminishing return while tuning #37695Troy, If some folks didn’t have knuckles that drag the ground they wouldn’t have so much trouble getting their arrows to tune. 😛
Here’s a link to the thread on Internal Footings.
Check out Kingwouldbe’s post on his external footings too. It’s another option for needing to stiffen the spine on longer shafts (or bows with deep cut risers).
Bottom line is you only have a few options: a spine stiffer than 300, tapered shafts like the Grizzly Stik or Momentum, internal footings, external footings or building out the riser. Those old Beman shafts are a perfect fit but heavier than the hardwood IF’s. There are other styles of IF’s too. O.L. uses a series of carbon tubes, one inside the other, in a step-down configuration. Works well too.
Ed
in reply to: Point of deminishing return while tuning #37568No, Troy, you didn’t overlook it. I intentionally didn’t put the shaft length on any of the arrow setup specifications. I’ve tried to stress to folks the need to tune their arrows to their bow. I found that when I put the shaft length some folks were just duplicating the setups I showed and considering them to be ‘tuned’. 🙄
You just had to find something to ask so that I would have to drag the Study computer out and look up in the data base to be able to answer, didn’t you? 😈 However, that particular setup had a shaft length of 689 mm. That’s approximately 27 1/8”. I used those shafts without an internal footing. I had some I worked up, but never used in the testing, that had an oak IF and they had a shaft length of 768 mm (30.236 inches) and weighed 755 grains, with a FOC of 33.9%. They never got tested because I ran out of time on my visa before I had a chance to test them on a buff. I intended to do them on the next trip but …:cry:
Edin reply to: Point of deminishing return while tuning #37485As badly as I hate to admit it … that WAS a good question, one I don’t think anyone has asked me before. Of course, THEY may have read the Updates first! 🙄 😛 Sure is good to have you back Amigo.
Ed
in reply to: My Setup Adequate for Elk??? #37429Scout, wait until after all the hunting seasons are over and they are destocking at Wally World. I’ve picked up shafts that were almost a give away. I try to hit them every year to pick up shafts for testing.
Ed
in reply to: Point of deminishing return while tuning #37421Troy Breeding wrote: When working for UEFOC is there a point in the setup where the speed and weight will out weigh the advantages of UEFOC?
Just wondering….. Did I finally find something that will make Ed stratch his head?
Troy
Didn’t even have an itch Troy! You don’t have to equate arrow weight with Ultra EFOC. The Ultra-EFOC arrow I tested on buffalo in 2008 (see the 2008, Part 4 Update, it’s in the ‘Library’) is only barely above the heavy bone threshols. It weights 655 grains and has 31.4% FOC.
Now go over to the 2008, Part 5 Update. It has the comparison of this 655 grain Ultra-EFOC arrow against other arrow groups from the same bow. I think it will more than answer your question.
Within the limits of what I’ve been able to develop so far Ive found no point of diminishing degree with FOC. Arrow mass is a different matter. At some point the arrow weight becomes too heavy to permit acceptable trajectory. That’s one reason I’m so excited about Ultra-EFOC. It’s demonstrated that a well tuned, lighter weight Ultra-EFOC arrow has greater penetration than a well tuned, much, much heavier arrow having normal or high FOC … and it equals the performance of a well tuned, significantly heavier EFOC arrow.
Ed
in reply to: My Setup Adequate for Elk??? #37074cyberscout wrote: Dave – Dr Ed
I was looking in 3r catolog and saw CE “Pile Driver” shafting with “Built in Weight foward Technology” — sounds good .
anybody used these yet – thoughts?
ScoutI haven’t used any of the CE Pile Driver shafts but one of my friends, who is very switched on, did get some to try. His evaluation was that the only ‘weight forward technology’ was that they added a wrap to the forward portion of a regular parallel shaft. That’s why the fore shaft is patterned and the shaft’s rear left ‘bare’. Sounds like a sales gimmick to me. Not any significant advantage of a regular carbon of comparable GPI weight.
Dave’s right about Wally World. It’s is a great place to pick up shafts, especially at the end of season. I’ve picked up a number of individual shafts for trial arrows. They’ve usually been finished arrows with vanes, but at ‘close out’ they are still way less expensive than bare shafts would be, so I just strip the vanes off, replace the aluminum insert and, presto, a bare shaft for testing.
Ed
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