Arrow speed

[bjansen]

Guys I have a question for you on arrow speed.  I just bought a Chronypal and got it in the mail yesterday.....and I have to say I am somewhat disapointed when i used it.  

I shot many of the bows I made that I thought were very fast through it and the results were much lower than I expected.  I fully understand that this measure is not critical in hunting situations nor does it have any effect on things that matter to me (acccuracy, ease of shooting, handshock)...but I think it does speak to the skill of the bowyer in some fashion.  Here are the results of  my finest longbow...

Thanks guys

My most recent 55# @ 28" 68" T/D longbow- Bingham Design...the last one I built.  .040 clear glass w/ wood core, pencil thin tips with phenolic overlays, FF string, absolutely the best shooting bow I have.  

At my 27.5" draw, finger release, a 508 grain arrow shot 166 fps.  
At my 27.5" draw, finger release, a 568 grain arrow shot 155 fps.  

let me know what you guys think.....and does anyone know of a reference to which I can compare arrow speed to.  In TBB they often reference "average", quoting the FPS comparatives to wooden bows built...but I could not find these "averages" anywhere.

[Dano]

An average I use is, 100 fps plus draw weight. So a 55# bow would average 155 fps. I don't own a chronograph, they just depress a guy.   :rolleyes:

[Pat B]

A good rule of thumb for average arrow speed is to add 100 to the draw weight so a 50# bow should shoot 150fps.
  A few years ago I shot one of my self bows through a chrony and was very disappointed with the results. I have not done it again and have been very satisfied with every bow I've made since then. I don't believe arrow speed has anything to do with the bowyers ability. It is all what you are looking for in a bow.

[Pennsyltuckey pete]

Arrow speed is a function of physics.  It all boils down to Mass and Energy. The Higher the Mass the slower the arrow.  The higher the energy (Draw Weight and Power Stroke) the faster the arrow. Mass is found in the limbs, the string and the arrow.

Your bow is doing fine.  Remember - Figures don't lie but lairs can figure. I have seen a lot of that during the years.  I guarantee if you take your bow out someone will say "Wow that thing is smokin Your Pushing 185fps just like me" Just smile say thank you and know the truth.  How many inches in to the dirt after a pass through is enough penetration?

Accuracy is what kills.  As kids we were all mislead by the commercial "Speed Kills"

pete

[dutchwarbow]

Bj, the bows most pleasant to shoot are usually not the fastest. somehow those real fast bows multiply your errors...

Nick

[mater]

My bows compare to your numbers. You shooting a true 27.5" has alot to do with speed. Alot of guys shoot through a crono with a exagerated draw to get there numbers.
  Mark

[bjansen]

Thanks for the input guys. I do appreciate it.

[StanM]

Crank that sucker back to 30" and see what happens     At 27.5 inches of draw and over 10 gpp I think that you are getting a nice speed at 155. As mentioned above there are many factors that need to be considered when comparing speeds to be certain that you are comparing apples to apples.  

Stan

[sw]

Bjansen, i feel your pain  

The first time i got a chrono and measured my first bow i was about to give up bow making. BUT at the same time they are VERY useful tools and what helped us make 200+ fps bows.

Heres what im seeingby your figures, i think i can relate as i started from making bingham bows and you got me thinking. It loks like you are shooting 9.23 grains per pound at a 27.5 inch draw. You didn't state your brace hiegth but we'll assume a decent 6 to 6.5" on that bow.

At your draw and at 9.23 ggp at 166fps you are doing well on a longbow. People put WAY to much stock into speed. Of course we do as well, its how we sell bows BUT let me enlighten you a tad.

Standard testing is usually done with a 30" draw, FF string at 7 to 8 grains per pound with a mechcanical release. Now where a "good" bowyer enters being a craftsman is when you can get good numbers at real world levels - try 28" draw, FF string using 8.5 grains per pound with fingers. If your getting 175 using that it would not suprise me and THAT out of a longbow - straight bingham design is a GREAT speed. From there - is it quiet, is it stable, is it smooth and is it consistant - if so - your building great bows..... I bet you hit 175 with using the above.....

Don't stress the numbers, if your going to do this for a living then you need to start experimenting and stressing the numbers - BUT when the chips are on the table, anybody thats going to buy a bow will take 166fps if the bow is smooth, forgiving, light and consistant over a 180+fps bow that is a poor performer where it really counts. To get the fast bow and the easy mannered bow takes time - its not imposible tho and you are looking like your on the right track - if not already there....

Dave

[Apex Predator]

Chronographs will make you get a sour taste in your mouth when you look at "old reliable" hanging on the rack.

I test during R&D for comparative analysis, but don't care personally.

Dave, any bow will shoot 200 fps with a light enough arrow.

AMO testing is done drawing 30" with a 60# bow, and 540 grain arrow.  There is no "standard" for testing trad bows, but the one used at WTT should be standard.  Shooting machine, mechanical release, 6.5 brace, 28" draw, shooting 10 grains per pound.

You backyard guys can expect the machine and release to add 6-8 fps.

[TradBowyer]

Bjansen,
welcome to the numbers world LOL. I got a chrono a while back just for this reason adn it will open your eyes a lot. The only way to really gauge a bow is to compare it to standard. As previously stated, there is no standard for trad bows so I used the next best thing which was Blacky's test in TBM. He tests each bow the exact the same. 9 gpp arrow, 16 strand fast flight string pulled 28" with fingers and a release but I'm only interested in finger releases as that is what guys are going to shoot. I got every magazine that I could find that had a bow test in it and wrote down all the numbers. The average D/R longbow is going to be in the mid 180s with the highs in the upper 180s, the average recurve will be 188+ with a high of 192 (off all the bows he's tested that I have access to). changing any of these variables will change numbers but that is what I test all my bows to so I have a reference.

I also tested Binghams bows as those are the first ones I started on and your numbers are right on for those designs. Bingham designed a bow that anybody could build and get a shooter out of but you sacrifice bow performance when you do that. Bingham designs are excellent bows to begin building but if you are looking for a fast shooting bow, use them as starting points and tweak the design. Those bows aren't designed for speed.Again, i'm not trying to put these bows down, just stating facts

[bigcountry]

My latest IPE/boo, I was pleasently surprised to see 165fps with 9gpp.  Its 55lbs at28", and I bet it would shoot 160fps with 10gpp.

But I am kinda surprised a fiberglass recurve does't kick a 10gpp arrow out at 170fps.

You might see 5fps variation too.  I agree however, I do think it is a good scale for how well a bow is tillered, and designed.

[sw]

Apex, i absolutely agree any bow if pushed will fire 200+, what i was saying is when he/she can make and get a bow to smoke out an arrow and still have the bow quiet, consistant and smooth.

I had heard somewhere that the standard level of testing was at 7ggp, 30" draw, mechcanical release ect - i may have my facts wrong - wouldn't be the first time   .

I know we test at 28" of draw, 8.5ggp and usually right around 50 to 55 pounds with fingers trying to keep things in a real world area and at that level having a smooth, forgiving and consistant bow is very achievable that hits 200fps.

I also agree that a chrono can really open your eyes in a bad way - but when developing a bow and combinations it is a priceless tool.

160 to 170fps is not at all bad for a hill style longbow.


Dave

[Diamondback59]

HEY  BRAD  I FEEL UR PAIN HAHA ME I SAY THROW THE DAMN CRONO  OUT  IT DONT KILL GAME   AND IF IT S TO FAST AND NOISY  WHATS THE POINT ???   I GOT SOME MORE IDEAS  FOR YA  WHEN WE TALK AGAIN  BROCK

[Jesse Peltan]

AMO testing is 60#@30bow 540grains arrow (9gpp) drawn to 30. If you bow shoots 200 AMO, at 28 it will only do 185-190fps. So at 9.5gpp and 27.5in draw 166 isn't bad. If you adjust for 27.5 to 30 you get 179-185fps. And for 9.5 to 9 even higher.

[Roy Steele]

DEAD IS DEAD NO MATTER HOW FAST YOUR ARROW GETS THERE.
  Beside you can't mount chono's and they tast like #%*&.

[limbcracker]

Test your weight scale. Mine when out of wack and my new bows were all shooting slower than the old ones, until I discovered the problem. Chronos are a good tool to learn how to maximize a bows potential as you tiller and test, I learned to get 10 fps out of most bows by thinning the tips alone. But speed isn't everything, or we would all be shooting compounds! The best feeling bow is the best bow and will kill the most game for you. Good Luck, Kirk

[stickmonkey]

Also remember when you are setting the benchmark to compare apples to apples. Simply comparing two d/r bows is not enough. Consider the effects of design, riser length,specific gravity of the lams used, the actual lams that are used and the profile of the bow. All of those things can and do change the rate at which the energy is transferred to the arrow.