Several folks here have been waiting on me to finish an all bamboo bow and post some numbers. Here are my results of tonight's testing.

Bow = 64" Reflex Deflex "Eclipse" model. String = 12 strand TS-1 flemish fast flight. Limbs = 3 laminations of vertical grain babmoo under .050" clear glass.

Arrow 30" Gold Tip carbon 3555 with a 145 grain tip, fletched with 3 - 5" feathers = 431 grains.

Draw was verified by a watcher to be exactly 28" (marked on every arrow), shot with a finger release using a cordura glove.

Speeds averaged at 184 fps, with highs at 187, lows at 182.

How is this for a 47# bow, shooting a 9.2 grains / lb arrow??

Thanks, Crazy Arrow

ONE CORRECTION - The arrow was 31", not 30". Sorry. Weight was accurate, just made a mistake on the length.

Nice looking bow-good work!

very nice bow !!!!!!!

In my "not-so-professional" opinion I'd say that's excellent speed for a R/D longbow.

ncie bow :)

chris.

I like the limb profile and the slim handle

Looks alot like the shape of the ACS I got my paws on last night... Good speed...my 46#er is doing about the same with 9 gpp..186 avg.... Now, lets getter up to 190!

Ernie

Arrow weight of 431 grains times velocity of 184fps^2 divided by 450240 gives you arrow Kinetic Energy. Divide that by your draw weight and you get a KE/draw weight ratio. Your bow is at 0.69 typically I see numbers from 0.60 to 0.74 I figure 0.70 is about average for modern bows.

200 fps AMO gives a KE/draw weight ratio of 0.80

CA, absolutely love the riser and the strung profile.

Longshot, Thanks, the riser is curly maple and bubinga, with accents of red and white .030" glass.

CA

Crazy, for an all wood bow that is about as good as it gets, excellent job!!Steve

Wow Etzel that is like the most civil post I believe you have ever posted.

Good work, hope you are finally coming around to see we can all get along even if we like different things.

Info for Etzel (and others)...

What kind of bamboo did you use? I use Vertical grain bamboo cut from flooring.

What kind of glass did you use? Binghams .050 uni

How long is the riser? 19"

What are the brace and tiller? Brace is 7.0 ~ 7.25"

It is 64" UNstrung.

Thanks, CA

"Arrow weight of 431 grains times velocity of 184fps^2 divided by 450240 gives you arrow Kinetic Energy. Divide that by your draw weight and you get a KE/draw weight ratio. Your bow is at 0.69 typically I see numbers from 0.60 to 0.74 I figure 0.70 is about average for modern bows. 200 fps AMO gives a KE/draw weight ratio of 0.80 "

The ratio doesn't take into consideration draw length (power stroke). Since this is just as important as grs/lb, directly comparing ratios is only valid if the draw lengths are the same. Since the AMO standard is done with a 30" draw, its not surprising CA numbers taken at 28" would be lower.

I posted the AMO value separately from my other statement for informational purposes not as a direct comparison of his bow to AMO standard. His question was "How is this for a 47# bow, shooting a 9.2 grains / lb arrow??"; I'd say about average.

Are ypou guys considering bow length with these numbers?

I mean, shorter is faster right?

Not exactly Stag there are too many other factors in the design that comes into play to just say shorter is faster.

Those numbers are very good up there with some of the top performers.

Etzel, That bow is now on it's way to the guy who requested it, so can't weigh it for mass. It is very light, but I would not venture a guess.

I will PM you also, I am always open to ideas based on other people's experiences. That is how this bow came to be, I read everything I could (and still am), looked at the top bows out there, and tried to use what I felt was a winning combination.

Thanks, CA.

450240 is a currently used version of an obsolete number, 32.16 as at one time the value of pounds per slug was 32.16 now 32.174 is used except when calculating KE

the KE equation is .5*mass*velocity squared

mass is in slugs so you divide grains by 7000 to get pounds then you you divide by 32.16 to get slugs as there are 32.16 pounds per slug actually there are 32.174 pounds per slug but the commonly used KE equation uses the old value of 32.16.

.5*431/7000/32.16*184*184 = 32.4 = .5*431*184^2/450240

Correction

.5*431/7000/32.16*184*184 = 32.4 = 431*184^2/450240

I removed the .5 from the last portion of the equation as 7000*32.16=225120 which is .5 time 450240.

Ah, Yes!

A subject of the Queen.

Welcome to the free world!

Crazy arrow, how fast would the bow shoot if it is drawn to 26"????

Longbowman, That, my friend, is a very good question. Here is my best guess....

At 26", draw weight will be in the 41# range (you loose 3# per inch of draw under 28"). So with all things constant, ie arrow weight etc, I would guess it should shoot about 175 fps. This is only a guess, but should be in the neighborhood.

Actual testing is the best method of course.

Thanks, Brian

Great speed!

No matter what the exact numbers.. Great looking bow with some VERY good speed..the new owner should be very proud and happy to get it..and you should be too for making it.. Great job!!!

Looks and sounds like a shooter to me! Great job!

Great numbers all around. Beautiful to boot. Excellent. Gil

This bow was shipped to SPAIN, so not likely that I could get hold of it to check speeds at shorter draw length.

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