Can this be the future of bow design?

Rangeball · 08-26-2003, 10:51 AM

I think we' d all agree that a big emphasis in recent years has been making bows that are faster and faster each year. I' m wondering if cams are being designed to favor IBO spec at the expense of AMO type specs?

I' ve been playing with my chrony lately, and while originally I shot a 350 grain arrow at 287, removing the string leach and changing to a white teflon slide jumped the fps up to 295, a 2.79% increase in performance.

However, I originally shot a 500 grain arrow at 250 fps, and without the leech and with the white slide it only now does 252, a dismal .8% performance increase. I expected more...

This leads me to believe that cams and or bows are being designed to favor reaching max spec at a certain weight arrow class. Perhaps in the future we' ll see bows designed and sold based on a specific weight range of arrow you plan to shoot?

Is it possible, or am I way seeing something that' s not there?

Arthur P · 08-26-2003, 11:04 AM

They are designing bows to shoot light arrows more efficiently, there' s no doubt about that. But in this case, I think you' re seeing one reason I choose heavy arrows for my shooting. Minor changes don' t affect them nearly as much as the same changes affect light arrows. Think what would have happened to your light arrows if you' d been trying a shot from the bushes at a big buck and a twig or some leaves tweaked your string on the release. Just a little interference can make a big difference in point of impact. Heavy arrows aren' t affected nearly as much.

walks with a gimp · 08-26-2003, 11:23 AM

Art has a good point and consider the affects of rain and snow or cold can have on a light arrow set up. More chances to have your light arrow loose some velocity in extreme conditions compaired to a heavy arrow, say 450 to 500 grains or more. I really enjoy shooting my 2315' s at 530 or so grains.

Deleted User · 08-26-2003, 11:50 AM

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PABowhntr · 08-26-2003, 12:15 PM

Very good observation and probably very true. It would explain why many folks are reporting better KE numbers at lighter arrow weights.

Rack-attack · 08-27-2003, 08:15 AM

Sure I agree, Just like some motor designs will produce more horsepower and some will produce more torque. With that IBO rating the first thing people look at and speed being what it is today - I can see certain cam / bow designs that work better at the IBO side of the scale.

Fine with me - I don' t plan on loading up that arrow anytime soon

Hey Art - you can put up many good reasons you shoot heavy arrows without grasping for limbs there

Range - I think you will see results similar to yours on any bow for a simple reason. The weight of the leaches represent a greater % of total weight being pushed with a lighter arrow setup than with a heavy arrow setup.

using a weight of 30grns for two leaches:

that represents 8.5% of the 350 grn arrow
that represents 6% of the 500 grns arrow

That could be responsible for the diff in performance %' s you saw on your test

Rangeball · 08-27-2003, 08:20 AM

Hey, that makes sense...

Must be something wrong with the statement

Arthur P · 08-27-2003, 08:27 AM

Quote:

Hey Art - you can put up many good reasons you shoot heavy arrows without grasping for limbs there.

LOL, R-A! I be aswinging in the branches like Tarzan.

You said it perfectly:

Quote:

The weight of the leaches represent a greater % of total weight being pushed with a lighter arrow setup than with a heavy arrow setup.

ANY interference or change represents a greater % of total weight of a light arrow vs a heavy arrow and so is going to have a greater effect on the light arrow than it would on the heavy one.

Pinwheel 12 · 08-27-2003, 09:00 AM

The industry is now moving away from the " solocam craze" that bogged it down (IMHO) for so long, and now that we are experiencing the new trend towards perfectly straight and level travel with smoother ecdentrics that still generate extreme speeds, the efficiency of energy transfer will become much more apparrent. Of course, a heavier (stiffer) arrow will always absorb more energy, but the problem for a long time when they first came out with the solos was that they lost a boatload of energy due to the horrible nock point travel. So they jacked up the draw force curves some more, introduced mechanical broadheads, and it was forgotten by most for awhile.... Luckily we are coming around now.

Bows will always progress in the speed dept. simply because people WANT it. Newer materials with quicker response times, super-rugged risers, etc, will become the norm, along with new technologies with which to propell arrows.Thus efficiency across the board will also rise, even with lighter weight arrows. (built with stronger materials and processes also BTW!)

Remember that a mere 20 years ago we were all shooting bows that would be hard-pressed to hit 200fps with a tailwind. Now we have bows that can shoot the same weight arrow at over 300fps, and some pushing 350fps. In another 10 or 20 years-- who knows, but 500fps certainly isn' t a pipe dream whether you are for or against it, and neither is generating extreme kenetic energy to boot.

I personally like to shoot a heavier arrow out of my hunting setup also, and can still hit 260-ish at over 130g past IBO legal. Compare this to the 160-180fps I would shoot the same weight arrow at 20 years ago out of my old thunderstick, and I can safely say " we' ve come a long way, baby" !

I always look forward to the future as well, always some kind of new gadgets that will wow me every year. My advice---Don' t fight it, ' cause it' s gonna come anyway. Have fun with it!

Try everything---if it doesn' t " float your boat" , then you can say it' s junk with finality,(I' ve done this with many new " fad" items myself) but alot of times we all might find something just a touch better than what we used to have.

Good shooting, Pinwheel 12

JeffB · 08-27-2003, 09:29 AM

I definitely think that most cams today are geared to provider better efficiencies w/light comparatively.

Most singlecams provide his benefit (many dual cam gurus believe it is because the single cam has a harder time accelerating the heavier arrow due to the balance issue of having a cam on the bottom limb only. I"™m not so sure I agree with that, but you"™ll see that explanation tossed around by some)

Bowtech"™s Black Knight cams (from 2002 and previous) are definitely designed to step up the speeds as arrow weight gets lower and lower compared to many designs. On the heavy poundage, longer draw lengths those cams are picking up 1 to 1.5 FPS for every 2 grains of arrow weight lost as it nears 5 grains per LB. It"™s just insane how they work so well w/ light arrows.

I have a "œtheory" of sorts. Cam designs that peak very late and drop off late tend towards the better efficiencies w. lighter arrows. Cams that peak soon and drop of a bit sooner/smoother tend to handle heavier arrows well. I think the sudden jolt as the cam/cams on a late peaker hit the arrow with lighter mass, it"™s much easier for them to get that arrow in motion, as opposed to the heavier arrow. On the early peak bows, that heavy arrow gets a more gradual sendoff that is smoother but is consistent over a longer duration which does not "œslam" the arrow so hard, makes for less oscillation, etc. Thus they get a bit more efficiency that way.

Considering that the BK cams, and the vast majority of Maxcam copies adhere to that late peak, steep drop-off, and singlecams especially tend to drop off efficiencies w/ heavier and heavier arrow weights this makes sense (at least to me

)

Hybrid cam designs like the CPS & C.5 (haven"™t tried Merlin"™s design, so I cannot say) seem to have a more balanced approach. They handle light arrows very well & heavy arrows very well. They are more efficient across a wider spectrum of arrow weights, without having the extremes at either end of the arrow weight spectrum.

Bowtech"™s new dual cams due to their redesign also seem to have a more balanced approach compared to their predecessors in this regard. I"™m seeing better efficiency with heavier arrows, and slightly less efficiency w/ light arrows as compared to the BK cams. If you are familiar w/ both cam designs you will notice that the new cams peak sooner than the BK cams did across most draw lengths and models (though a few still peak very late like the BKP).

People LOVE to see those top end numbers, myself included. However come hunting season, I throttle back to my comfortable hunting speed range (275 to 290 or so, depending on the particular design) which generally puts me around that 6 grains per pound range of arrow weight w/ the bows I have had in the past couple of years.

I think the industry would be best served with taking the approach of the hybrids, where a broader range of arrow weights proves very efficient in a given bow. This will satisfy those like Arthur who like to shoot 351 Clevelands, and others who like knitting needles.