Long bow tweak- Test results in

[Kirkll]

The Flatliner design typically averages low to mid 180's at 28" in the 50 pound range but does better at longer draw lengths. The hybrid & recurve designs i build do a little better than that.
 
But the lower poundage bows always taper off in performance. I would have to dig deep to give you exact test results i did years ago, and i'm really not interested in getting into any debates over those results or splitting hairs right now.

My goal here was to tweak the wedge configuration and core material in this limb design to see if i can get a bit more horse power at 40 @ 28". That's it.... I'll most likely test it at 9 & 10 gpp  at 28"  & 30" just for fun too. 

I was just thinking that you guys might enjoy going along for the ride. I've got nothing to prove. My limb designs are solid. Purely just sharing some tinkering here.... I rarely do much testing any more.   Think of it as entertainment.

Kirk

 

[Kirkll]

Speaking of entertainment.... Check out this clip of me doing some testing on my first home made shooting machine. I just finished a custom built a light kit using appliance light bulbs that worked pretty well.... Well for awhile anyway....

[Stagmitis]

Testing to customer specs may be a good thing but somewhat subjective- A shooting machine is not fingers. In my testing I lost about 4-5 fps using fingers VS a shooting machine with a release. On top of that I could manipulate the speed with fingers by up to 4-5 fps depending on how I released and pushed forward into the bow. If I shot naturally that would not happen. Also, a longer power-stroke over 28" on any bow shows significant speed gains.

I would love to see the bow you just built run through the chrony at 28" @ 10gpp-

[Shredd]

Ok..  Cool... Thanks Kirk...

Stag...  Good things to take into account...  For any new guys out there a shoot machine and fingers are two totally different animals...  Like Stag said, fingers can vary alot and should never be used if you want accurate comparisons... A shooting machine is so easy to make...  You could put one together in about a half a day or maybe less... I have pics on one of the threads of mine if anyone cares to look it up... If you are building bows and concerned about performance a shoot machine is a must have...

[Kirkll]

Yup…. A shooting machine is a great tool to measure your gains and losses when tinkering with your limb designs by accurate comparison. Your mileage always varies between archers when shooting by hand.

Another thing that can vary your test results is how long you hold the bow at full draw, type of string used, tied on arrow nock vs brass nock. Shooting bare shafts vs feathers or vanes…. The only way to accurately test one bow from another is using everything the same. String, shafts, and the same shooting machine.

I built a release for my shooting machine shaped like fingers one time with a button that pushed the string off a finger shaped hook. I did the same with my tiller tree hook for my scale trying to get as close to fingers as possible.  That is when I realized the difference in draw weight varied slightly from a straight hook to the wider fingers hook. Not much…. But it was there…

You can really get into splitting hairs on this if you are so inclined to do so.

Kirk 

[Shredd]

   Hey Kirk...  I was thinking...  Next time you want to entertain us, just say I'm building a new bow...    If you say I'm going for better performance, you got a few guys out here chomping at the bit with their note pads out...  Don't tease us like that...      Your committed now...   

[Kirkll]

Well…. I share a lot of detailed info on how I build my bows that a lot of seasoned professionals don’t. I make recommendations based on experience and if you guys want to take notes and benefit from it, that’s  cool. If not,  you can take it or leave it.

 I do have a bit of a problem with answering detailed test result questions, and being told what is appropriate, and what is not regarding my testing procedures. I have nothing to prove to anyone, or is it my intent to do so. If the info I provide is useful and helps someone….. that pleases me a lot. If not, please don’t ruin it for others that do appreciate my efforts to share experience.

We got a serious heat wave going out here in Oregon right now with 100 degree plus days. That is limiting my shop time that turns into an oven rather quickly. So you guys that are champing at the bit will have to be patient. I’ve still got overlays to complete before I test this long bow. Might take a couple more days before I post my results.

Kirk   

[Kirkll]

I'm a little busy today so i'm going to keep this short and sweet.

40@28 , 10gpp , 184 FPS ,  9 gpp 188
42.5 @ 29"  10 gpp = 186 FPS  &  9gpp jumped to 194 FPS (customers draw length)

Summary =  Extending fades did increased performance at 28" , 29" & 30" of draw.  PPI was 2.5#from 28" to 29" draw, but jumped to 2.9 PPI at 30" and was showing signs of stacking an inch shorter than normal wedge length.   Test results for 30" draw was similar to 29" only 2 FPS faster.

I'm happy with it. It wasn't a huge gain, but  it did bump it up about 5-6 FPS. 

Shooting by hand feels smooth to 30" draw. It probably starts stacking at 31" the way the scales were reading.  64" bow length of this design typically doesn't stack until 31- 32".     Kirk
 

[Shredd]

  Great...  Sounds like you reached your goal... 5 to 6 fps is a huge gain in my book...   

[Buemaker]

Very good. 5 feet gain is an excellent result.

[Shredd]

Now try that same layup at 45# or 50# and you might hit 189 fps...

[Kirkll]

My 45-50# bows do just fine with a standard length wedge using bamboo and maple cores, and have a better draw length range. So I’ll probably just stick with my standard lay up in the future.

I’ve done a lot of draw length specific lay ups with my RC and hybrid limb designs to help a customer gain a bit more HP. But…. If and when they sell that bow it may not be ideal for the next archer with a longer draw length.  This is the first time I have altered the wedge length on this limb design since It was prototyped. I would do it again for 26-28” draw length request on a low poundage bow.

If I were to to start messing around trying to increase performance further in a 40 pound or less draw weight, I think I would drop the taper rate to .003 FT or even go to .002 FT to help increase the stack thickness in the working portion along with the longer wedge and lighter weight core.

The possibilities are endless…. if you are more interested in tinkering than putting out a consistent high end product, you could spend years spinning your wheels and have a shop full of prototype bows instead of refining your craftsmanship and selling the product…..

Nothing wrong with that either…. If it’s a hobby, have fun with it…. Kirk

[Stagmitis]

Kirk, dont think for a minute that coughing up your knowlege doesnt go unoticed or isnt appreciated- Thanks for posting those numbers 

[Mad Max]

Kirk, dont think for a minute that coughing up your knowlege doesnt go unoticed or isnt appreciated- Thanks for posting those numbers 

Yep