I just can not explain this

[Granite Mtn]

I am not a new bowyer,  I have been makin self bows since the summer of 1989.  Hundreds of bows to my credit.  Several years ago I had an osage scrap, side split from a full grown stave if I remember right, setting in the corner I intended it for a kids bow.  Any how I grabbed it and on a complete whim roughed it in floor tillered it then deflexed it through the handle alot about 4 in put a short recurve to the tips and sinewed it with TB III.  I finished tillering it about a month later, put snake skins on the back, and shot it in.  It pulls about 74# at 26 in, it is 54in ntn.  I usually shoot really heavy arrows 800gr plus and this bow shot them ok but nothin to write home about.  I had some birch shafts that finished out around 650gr I was going to use in Tx for hogs so I shot one of them, I about crapped myself..  That bow shot them soooo fast i could not believe it I took it on the hunt and killed 9 hogs using birch shafts and tusker 100 gr heads.  Since that time I have made several bows using this principle including BBO and BBI.  I have shot them through a chronograph and they do not stand out next to conventional straight, R/D, or sinewed recurves until arrow weight drops to below 10gr per pound then they blow the other bows away.  I shoot bows in this weight 70 to 90 because I like them, I get to hunt dangerous game at least once a year so they give me pleasure.  I want to be clear, the tips on this style of bow set behind the handle 2in to 4in when unstrung and very little movement is necessary to string the bow, the string angle is very low even at full draw.  I do not want to get beat up for posting, I would like info if others are experimenting with this type of bow, or any physics majors have an explanation for why these bows perform so well for me.  Thank you for your time.

[islandpiper]

Pictures will help.   Think of them as "bait" to get guys posting.  piper

[coyote pup]

Sounds interesting. I can't help ya explain it though.

[Ryano]

I guess I don't understand what your asking? Any bow will always shoot faster with lighter arrows....

[Granite Mtn]

just woke up,  sorry I was unclear.  The bows have average performance shooting heavy arrows (when compared to other bows shooting the same arrows at about the same draw wt.)  Their performance picks up as arrow wt drops to < 10 gr/lbs. Again that is comparing other bows of more conventional shapes and less "set".  I hope that is more clear.  I will try to post pictures later I have never tried to post a picture before.

[Badger]

Granite, more than likely your short bows don't store a lot of enegy but seem to be efficient. Lighter arrows on your longer bows may not be getting all the energy out of the bow due to vibration. When you say fast how fast are you saying? A good experiment is to make a very heavy arrow like 1#. Then shoot it through the chrono, this will give you a good idea how much energy the bow is storing as it will be almost 100% efficient with any bow. Try this on a long bow and the short bow and see what the difference is. Steve

[king3933]

I'm no bowyer by any means but the lighter the arrow the faster the speed. This principle works with all bows.

[ballista]

 thats what i was gonna say too- but, hey- if it made meat.. some pics would be ideal, you got me reved up now haha

[Gordon]

I agree with Steve. Even though your short bows don't store as much energy, they must be very efficient - which would show more with a lighter arrow.

[roofus]

I'm no expert bowyer or physics major but here's my semi-educated take. The draw weight of the bow is what generates power. Like the arms of a great home run hitter.
The speed at which the limbs move foreward are what generate arrow speed. Like bat speed in the home run hitter.
A guy with huge strength will hit a ball out of the park on a high arc, relatively slow, where a bit less powerful guy might hit the ball out on a flatter line but at a higher velocity. Take a stop watch to a homerun derby and you will easily prove that.

So, i would agree that a lighter arrow will generally fly faster because it creates less resistance to the limb.
In a perfect world you would want to make as much power as possible with as thin (less mass to move) a limb as possible to get the greatest combination of power and limb speed.
Sounds like you may have hit in the middle somewhere, where you don't have as much power as you do potential limb speed so to overcome the deficit in power you have to lower the arrow weight to generate good speed. Kind of has to do with the theory of relativity. http://www.allaboutscience.org/theory-of-relativity.htm

[Badger]

Many years ago i took my son and my nephew for a hike, they were about 10 years old, we stould on the edge of a cliff and were throwing stones across a pond. I noticed they could throw very small stones further than I could but once the stones got a bit of weight to them I could easily outthrow them. I think kind of the same thing with the shorter bows and lighter arrows. Steve

[Granite Mtn]

I am on call and I got called away for a few day trip out of town.  I will try to post some pictures tomorrow if I do not go snowshoe hare hunting.  Badger you are following what I am saying, the rest not so much.  The thing that is most interesting is the amount of set these bows are built with would indicate poor performance but I have not found that to be true.  I think it may be because of the low string angle and short limb.  For those of you I lost earlier I will give an example, Long Bow x vs Short Bow y, Both bows pulled to 25.75 draw length,  both bows shooting 800 gr arrow LBx shoots 166 fps SBy shoots 152 fps.  Shooting 700 gr arrows LBx shoots 174 fps SBy shoots 172 fps.  Shooting 600 gr arrow LBx shoots 179 fps SBy shoots 183fps.  In simple terms no one would be astonished that a particular bow would shoot a lighter arrow faster duh, but as the arrows become lighter the short bows with built in deflex improve in RELATIVE comparison with other more conventional bows.  The data in the example given above is not accurate, I just used it provide better understanding to my question, although the numbers may not be 100 % DNO the relationship between the bows is fairly accurate.  When I shot the bows through the Chronograph, (it was last winter or the one before) I was shooting about 7 or 8 different bows that varied in construction, materials, and profile, but had very similar draw weights.  Hope that clarified my question, and has anyone else made short bows with large amounts of deflex that performed in this manner.