Arrow Speed Explaination Needed Please

[Diligence]

After reading Del's post about his cherry experimental bow, I realized that I really don't have a good grasp of arrow speed as it relates to draw weight, length, etc.

On Thursday this week, I shot my elm self-bow (46# at 27") thru a chronograph that the ten-speed wheelie boys were using indoors.  I was consistently shooting 133 or 136 feet per second at my full draw and hemlock shafted arrows.  (for reference, they were firing around 350 feet per second with their new hi-tech toys)

So, is 133 fps "good", "bad", "medium", "poor"?

and yes, I got lazy and didn't do a lot of searching on PA.....anybody care to kick me in the right direction.

J

[El Destructo]

How heavy of an Arrow were You shooting? Most of the Speeds that are being recorded are using AMO Weights....with an Arrow that weigh 9 grains per pound of Draw Weight...but others are misleading because they are using the IBO Weights...which are 5 grains per pound of Draw...If we try to make some generalizations about the two different ratings we could say that the I.B.O. speed rating is much faster than most archers could achieve......and conversely the A.M.O. speed rating reflects a speed that is less than what most shooters could achieve with the same bow...... If a bows I.B.O. speed rating is 220fps and its A.M.O. speed rating is 145fps that would mean the average archer would shoot that bow somewhere in the middle of that range.....at about 160-170 or so

[half eye]

Diligence,
        I know my take on "speed" aint to popular around this site but here goes an old mans opinion, for what it's worth. The one thing about speed is the weight of the arrow, and your wheelie boys (without a doubt) are shooting arrows so light the bows are on the verge of "dry-fire" condition....even Saxon Pope had Ishi make him a 300 grain "flight arrow" for his published tests of NA Bows. So there is that part of it.
       I notice in your post that you were shooting Hemlock shafts, and I also shoot a lot of heavier weight hardwood shafts, so that lost ya some speed.....but in gains ya in penetration especially on real-live critters. The heavy shafts are the absolute best at 20 yards and under.
       If you are hunting then noise is your enemy, not speed. Nobody has bow that will shoot anywhere near the speed of sound. So the light zippy arrows (and the bow that shoots them) are way noisier, than is a heavy arrow from a bow with good cast. The only thing that extra speed will give you is a flatter trajectory.....if your so far back that ya cant controll the "arc" a guy needs to learn how to hunt better (learn how to sneak up closer).
       I seriously believe that if you are way interested in speed and length of storke that makes a guy a "shooter" and if your more interested in quiet hard hitting game arrows then that makes a guy a hunter (two different things). So I guess it all depends on what ya want to do with the equipment. I've lost track of the deer I've eaten, but it was a fair amount ....and they all fell to heavy and quiet.
       One last shot at the wheelie dudes.....did ya ever notice that they are constantly "wrencin" on them things....tweekin sights, changin wheels, messin with arrow rests and all.....and ya can tell the the light arrow guys real easy, just look for the string silencers. It's sort of like dragster engines.....ya can make horsepower, but it costs in run time.

Put that 130+ fps in yer pocket and take that quiet dude huntin......don't think you'll be sorry. I'm gonna get my hole now and wait for the flack.
Rich

[Pat B]

Jaye,  For an selfbow shooting a 10gpp arrow a speed calculated by adding 100 to your draw weight would be an average speed. ie...50# bow should shoot 150fps.
   That said, I shot one of my bows through a chrono once and was so disappointed with the speed I never did it again.     My arrows shoot fast enough and well enough to take game and that is what I want in a bow.
  The only advantage I see to using a chrono is to achieve a bench mark to compare to as your tillering skills and the understanding of wood bow construction  improves. I now can tell by feel and sight if my bow is a shooter or a good shooter. 

[Diligence]

I just weighed all the five arrows I shot. They vary in length up to an inch.  Weights of 429,439,469,475,445.......so that's about 450 grains average.

so, I'm not too far off the 10grains per pound (ie. 450 gr average) rating by Pat's calculations means that I should be 46 +100 = 146 fps which isn't too different from the 136 max that I saw in the chrono.

If I use the 9 grains per pound, then 414 grains is what I should be shooting for the AMO weights, and my arrows would be heavy which I imagine would reflect a slightly slower speed.

Looks like I just learned that my bow shoots the way it shoots, and I should be happy with the performance.

As for noise, well, sometimes my bow sounds like drawer full of my grandmothers good china plates, and other times, it's a whisper.  Has to do with my release I think.

thanks guys - back to my 3 sick kids and sick wife.....what a fun Saturday.

j

[Pat B]

Getting as much even bending from your limbs and reducing the tip(or outer limb) physical weight will improve the numbers. Flipping the tips and tempering the belly will also. The more bows you build the better the speed will improve but if it feels good, shoots good and shoots where you are looking that is what matters. 
  Hope for a speedy recovery for your family. Being a care taker is a hard job.

[El Destructo]

I am with Pat...a Chrony is good for testing different Design...or for Tweaking a design that You already are working on...I take on faith in them...a Slow Quiet Arrow is the Deadly One...I have seen deer duck an Arrow moving at 345fps...My Arrow...and I have seen them drop to a  540 grain log from a 154 fps Pokey Wide Limbed Hickory Paddle Bow....My Bow....because They didn't hear it till it was too late!!

[Ranger B]

My .02

I've played around with weights a lot. When I shot a recurve (years ago) with carbon shafts I shot 375 grains. They shot very fast and flat in a 50# glass bow. I really never hunted with that bow - only targets....except for one turkey. I would have been comfortable shooting deer with that weight arrow.

In my selfbows I've played around with weight. I have ended up at about 475 grains for my arrows. They shoot quieter yet they aren't too slow. I bought a dozen tonkin shafts from David Knight and I got them at 390 gr. so that with a 125 gr. point, feathers and nock I'd again end up at just over 500 gr.  I am shooting them in an osage bow 43#.  I shot a video of me shooting them and I'll post it in a few days.  I shoot at 15 yards and then at 35 yards and you can see that they shoot fairly flat. I have no idea how fast they are but I did go squirrel hunting this morning with that bow and got 5 shots. On every shot the squirrel jumped my arrow. So my bow is either loud or a little on the slow side.  I am going to aim at their heads next time so I'll maybe hit them when they jump. I was shooting on average 15-20 yards and every time the arrow ended up right where they were sitting but they had time to jump. 

[George Tsoukalas]

Can we see the last 8 inches of  each of the limbs.  Your speed is pretty good. Jawge

[Kegan]

Jaye,  For an selfbow shooting a 10gpp arrow a speed calculated by adding 100 to your draw weight would be an average speed. ie...50# bow should shoot 150fps.

The 100 + draw weight is for a 500 grain arrow. The 10 gpp rule is to standardize it at which point 150 fps is average. I've neevr been able to chrono my bows so I'm not going to go calling anyone's speed "poor" and make myself look like a fool !

[Justin Snyder]

I'm with George, lets see the tips. You can often pick up a little speed/efficiency by eliminating excess weight from the tips.

Diligence,
I know my take on "speed" aint to popular around this site but here goes an old mans opinion, for what it's worth.

I'm gonna get my hole now and wait for the flack.
Rich

It always amazes me when people say things like that. Have you read many posts on speed around here? We have had this discussion many times and most people don't care about speed all that much. Don't get me wrong, I check speed on some bows, and try to get the most efficiency I can out of a bow, but it is efficiency not speed at any cost. If I can get 180 fps with a 500 grain arrow I will take it over 150 fps with the same arrow, anyone in their right mind will.

[Diligence]

Jawge,

To answer your question, here's a final tillering photo.  I don't have any other full draw pics, but the tiller has not changed as I have been shooting it in. (the left limb is the top limb)

Cheers,
J

[attachment deleted by admin]

[Jesse]

Is draw length figured in as well? I guess I just assumed the 10 gpp rule was for a 28" draw but if Im pulling 60# @28" then a 600grain arrow would be 10gpp but I would think it would be a lot faster than  60# at  25".   

[El Destructo]

Final Tiller looks good to me...shoot it till it Blows..

Glad to see a Workshop that looks worked in also........

[Diligence]

I've been shooting it since the end of February, and it's a real pleasure - thanks to your help with tillering advice!

As for speed, I think I'll stick with my 450 to 500 grain arrows, and see where it takes me.

Cheers all,
J