Rangeball

I've been doing a lot of looking at and thinking about how different FDCs affect our perceived effort to draw a bow assuming the same energy output. As for smoothness, I think this term is being confused with and used in place of "easy". I believe smoothness is more a function of lack of system friction. You can have a very stout pulling bow like the Bowtech BK2 that is smooth, but requires much more effort to shoot than eaier drawing bows.

For easy, I'm coming to the conclusion that a bow can only really store energy a few ways- By how much the limbs are pre-stressed, by cam design and by draw poundage. I'm thinking energy in equals energy out, and the same amount of energy stored then released into an arrow requires the same amount of work or effort on our part. For an arrow to travel X speed, it requires Y energy to push it. This can be accomplished by drawing a 70# energy wheel type bow (like the bowtech F cam)that gradually builds to peak, hits it then immediately gradually descends to the wall or a 60# hard SC or DC bow that ramps up to peak early, stays there quite a bit then drops to the wall quickly. Both bows are very different in how they store energy, but I feel the perceived effort on our part will be identical since they both store the same energy to launch the same arrow the same speed.

As for what we perceive as easy, I think that is up to the individual and their physical makeup. Some will have more strength at their disposal early in the FDC when using their larger back muscles. Some will have power in the middle and some late. That said, I'm really looking forward to putting the draw on the new BT equalizer system. I know what the Outback and Liberty draw like, and I'm shooting a BT PF SC so I've got the hit peak early stay there forever drop quickly to the wall covered. I do have a module on it's way to me that will allow me to test a FDC that only holds peak about 1" right in the middle of the draw which I suspect will let me move my bow from it's current 62# back to 70# to yield similar energy storage and perceived effort on my part.

That said, I plan on doing some major soul searching and testing before making a new bow purchase, to make sure the FDC I settle on is the one that fits me best.

Greg / MO

OK, Range... quick question for ya: If a particular bow's FDC causes you to "ramp up" to peak quicker than another -- but they both reach the same peak holding weight -- will the bow that ramped up quicker maintain more of a "push" behind the arrow for a longer power stroke, thereby resulting in faster arrow speed? Just wondering.

Rangeball

It'll depend on how quickly the quicker ramping bow drops to the wall. If it quickly builds to peak then holds it there a long time then quickly drops to the wall, then yes, it will store more energy and provide more "push" to the arrow, yeilding faster speeds.

However, where in the cycle a bow hit's peak doesn't determine which bow will be faster, it's purely a function of how much energy the bow stores. When you look at an FDC graph, the area under the plotted curve represents stored energy. If the area is identical, it doesn't matter what the top line looks like, the energy release will be the same. That said, the funkier the top line, the more variable the energy release to the arrow and the harder it may be to tune. Supposedly, FDCs that gradually ramp to peak then drop gradually to the wall are the easiest to tune with the widest variety of arrow spines, as the push of energy into the arrow is very consistent and even. This is one of the reasons the really aggressive SCs and DCs like stiffer arrows than the charts indicate, they are simply ramming a bunch more energy into the arrow very quickly, sustaining it then dropping off quickly. It takes a stiffer arrow to resist paradox.

Rangeball

I just received my "energy wheel" module and had to stop everything to got shoot it.

I shot a few shots with my bow at it's current settings to get loosened up a bit and to imprint the feel of the FDC. It hits peak early, holds it then drops off quickly to the wall. Here's what I found-

FDC- I then installed the E module, and stepped closer to the target, just in case I drew, and as soon as I hit peak the bow jumped back to full draw. I was so used to really pulling through to the wall that when the bow dropped of with the new mod, I was using a bit more effort than necessary. I let down and drew again, this time really concentrating. Bow easily feels a good 5# lighter in draw weight, just from a perceived effort stand point. It still hit's peak fairly early, but immediately gradually and effortlessly drops to the wall. I really enjoyed the FDC, much preferred over the previous mod.

Shooting- At full draw, the valley is more than adequate, but due to the less aggressive FDC, there is no tendency for the bow to take off when I crept a little bit, just to see what would happen. Subsequently, the release is really smooth, and the bow now has less recoil than the little bit it still had after all my previous modifications. I shot several times, and was really happy with how the bow drew, aimed and reacted at release.

Performance- My chrony needs new batteries and the lighting rig I had for shooting indoors is out of whack, so I didn't get to fling any through the chrony. It only makes sense that since the mod is storing less energy, I would lose some terminal performance. Diamond says the E mod yields 93% of the regular mods performance, and with the old mod I was shooting 278 fps. Applying there math, I should be now getting 259. However, my bow was previously sighted dead on at 25 yards, and my point of impact hasn't noticeably changed. Some day soon I hope to get my chrony set back up to do some testing, but for now I'm satisfied. I still have enough energy to get the job done, and if I want to get more performance, I can crank my bow back up. That's what I want to test, to see what the perceived effort is for identical terminal velocity.

All in all, I think this mod will stay on my bow. Time will tell.

Pinwheel 12

"Smoothness" or "ease of draw" comes directly from the overall stress on a persons' drawing muscles if they are running correct drawlength. If this is the case, then everyone would be the same, and a round wheel bow will feel smoother than a cam twin to everyone, and a twin will feel smoother than a solocam that normally exhibits a more radical force draw curve to maintain as close to the same speeds as twins. Hybrids are a mixture of both and will fall somewhere in between. This will hold true if there is no bias to one or another system.

As Rangeball has mentioned, the wheel bow ramps slower than a cam twin or hybrid or solo. Thus force at the shot is not as severe due to the lesser dwell, and speed is relative. Smoothness is perceived from the degree of ease of graduation to peak weight and dropoff, no matter the person, IF they shoot correct form and are shooting correct drawlength. A person with a 26" drawlength has that drawlength due to their stature, just as a person that shoots a 31" drawlength does. Their scapulae and rhomboids work the same tho because they are human, and are drawing to the same definitive point at correct drawlength. Strength factors are relevant only to overall poundage preferences, tho not to ease of draw or "smoothness".

When someone speaks of a bow with a high FDC being "smooth", you have to thus compare that in terms of whether or not that person has actually shot bows of lesser overall FDC over a given timespan to compare it to, or whether they are actually comparing them to other bows of the same FDC categorization, OR if they are just responding and saying they are smooth due to brand loyalty and they simply want to talk their favorite bow up.

Technically, the more gradual an FDC is, the smoother the system will feel as depicted in each systems' charts.

Bottom line--a "rough" cam system, no matter which kind-- twin, solo, hybrid, is just that, and the FDC definately comes into play. However, if you get used to it, it can be perceived to become "easier". Some may even learn to flat-out like it given enough time, and may even call it "smooth". Good shooting, Pinwheel 12

jmac_or

To look at one FDC, it can be hard to tell what characteristics the draw will have. When you overlay the curves, and ideally, actually shoot the bows with these curves, you really know what it feels like. This one has been posted before, but take a look at the different approaches and let-offs for these 4 cam systems. I shoot the Omega cam, and I love the draw. I used to shoot Mathews and there is a world of difference. I would love to have the raw data for these curves to plot different company curves, but I doubt that would be possible. Anyway, the picture really shows what is being discussed.
JMAC

Rangeball

Thanks Jmac... That's the EXACT graph I was gonna post, but I just got a new workstation and it didn't make it from my old one...

Now I can save it again, for future reference

For what it's worth, I expect the BT Equalizer to graph very similar to the Merlin R2 with target modules, the red line...

JOE PA

What Pinwheel said about smooth makes sense. The lack of sudden transitions into and out of peak draw makes the draw smooth. As far as easy goes, you can get used to the way your personal bow draws, and something different feels "wrong." I still tend to agree with Norb Mullaney and the newer Bowtech principles that say it is ergonomically better to pull more weight early in the draw than later. I personally HATE draws that increase in draw wt. after say 22-24". The Firebrand Discovery I had was the worst bow I shot for late draw increase. Couldn't get used to it, and my main bow at the time (Darton Mountain 2000 with CPS 2 cams) felt much easier to draw at the same weight. After my healing from my shoulder separation and then tendonitis in my draw shoulder, and lots of strength training, I can draw what I want again without worry, but I still prefer earlier peak and gradual letoff to anything else. Your opinion may vary!

Rangeball

One thing I discovered late yesterday when shooting the new mod some more. One of two things is occuring-

1- They designed and cut this mod to have a much bigger valley than most hard single cams have. I can settle in a few places, and not be at the wall.

2- The wall if solid, but requires a good 1/4" or more longer in draw length to get their. Don't know if this is by design or what, but I don't want to get into twisting my strings again for the sake of experimentation mid season, as I feel the only way to truly test what's going on energy wise is draw length for draw length, as I love a solid wall. At this point, I plan to complete the season, which runs through mid-January '05, with my first mod, then play around when I've got time on my hands.

500 fps

Performance for the most part is determined by the area under the curve. You can look at the green line for the turbo mod in the graph above and tell it's the fastest model because of this. The Bowtech Equilizer cam will look more like the turbo mod curve than the others. It reaches 328 in it's fastest configuration, so it has to have considerable area under the draw force curve to accomplish this. The "smoothness" is reflected in "rounding" the curve off as it approaches the dwell and also as it drops into the valley. A silky smooth draw most closely resembles a parabola (red), and the fastest, harshest FDC would look similar to a mesa (black).

Actaul draw force curves on actual bows, are a compromise and blend of these two to reach the desired shooting characteristics (smoothness vs. performance)

In a nut shell: anything you hack of the black to make it look more like the red will cost you speed but smooth things out.