Hi tech redneck flight bow.

[Jim Davis]

Far more certain  to succeed if you reduce only the width. 30 percent narrower should put you at about 35#.

[sleek]

Reducing the width is a great way to reduce draw weighr, but only if the bend radius isnt over stressing the limb. Considering the ser this bow took, its safe to say thickness reduction would decrease bending stresses, allowing the draw weight to match the bow width more. That combination should increase bow speed and efficiency.

[Selfbowman]

Jim I respect your suggestion and would go with your recommendation if I was making it for a daily shooter.  I agree with sleek on this one. I was told by Badger that it was toast for flight. Damage already done. So I’m just thinking on this for awhile.

[loefflerchuck]

We missed you at flight this year Arvin. Can't wait to see you next year breaking a record with this thing. I've also been toying with modified designs from the Greyson Museum collection from the golden age of flight here in the 1940s and 50s. I'm only going for records I don't have yet. This year I was 8 cm short of the 50# simple composite. For that one, I just need to brush up on my form. Want to bring a 80 or so pound bow for the unlimited class.
Take care

[Bob Barnes]

We missed you at flight this year Arvin. Can't wait to see you next year breaking a record with this thing. I've also been toying with modified designs from the Greyson Museum collection from the golden age of flight here in the 1940s and 50s. I'm only going for records I don't have yet. This year I was 8 cm short of the 50# simple composite. For that one, I just need to brush up on my form. Want to bring a 80 or so pound bow for the unlimited class.
Take care

I'm absolutely convinced that you will accomplish your goals.  I'm looking forward to seeing what design you come up with and watching the progress.  You and Arvin are my heroes. 

[Selfbowman]

Chuck I missed being at the shoot also. I heard it was a good one. I just barely broke the 50# complex composite record. It’s not easy shooting farther than a guy from Hungry . Stop trying to push that arrow another 5 feet and you will brake that record?🤠🤠 missed seeing everyone most of all. Great group of people from around the world!

[Selfbowman]

After studying the bow more I realized I had left the last 6”” of the limb was to wide . I left it wider till I got my string groves in. Then the dumb cowboy forgot to narrow them causing the set at 18-19 inches from center of the bow. I narrowed the ends allowing the recurves to work more. The set stayed but the bow shot 199 grains 226 fps. So had I followed the design it would probably been spot  on. It may still compete if I get good clean arrow flight.

[mmattockx]

After studying the bow more I realized I had left the last 6”” of the limb was to wide . I left it wider till I got my string groves in. Then the dumb cowboy forgot to narrow them causing the set at 18-19 inches from center of the bow. I narrowed the ends allowing the recurves to work more. The set stayed but the bow shot 199 grains 226 fps. So had I followed the design it would probably been spot  on. It may still compete if I get good clean arrow flight.

How much extra width was there? It doesn't take much to screw things up if you have everything right to the limit of the material. Great news that you found a reason why things went the way they did. Not knowing what went wrong is far worse.


Mark

[Selfbowman]

Mark I took off about 1-16 inch off each side from tips to nothing at 5-6” length.  It was enough to make a difference for sure. Making working recurves in all wood bows are a challenge to say the least.      I learned from the build though. This is my second try at this if I don’t run out of good wood staves that will make good candidates for a build I might get this right yet. The next one I will get the engineer to give me projected bend profile every 4” of draw length. I noticed the force draw and bend profile came real close to the design. Mark do you have both force draw and bend profiles in your design? And if so would you check the profile  design vs  force draw on one of your bows and see how it came out. I’m curious about this because thickness will be a lot less of an issue when tillering.

[mmattockx]

Mark do you have both force draw and bend profiles in your design? And if so would you check the profile  design vs  force draw on one of your bows and see how it came out. I’m curious about this because thickness will be a lot less of an issue when tillering.

Arvin,

I'm not really equipped to do an F/d chart on my tillering tree and I've never compared the bend profile of a bow to the predicted one. The last lam bow I did I was using Perry reflex to try and improve performance and I have no good way to include that in the analysis, so the bow I made was not really identical to the design version. When I get done building a garage and other infrastructure projects I would like to do some bows without the Perry reflex, just to see how they compare.

The design equations used are well proven to match reality, though, so as long as the bow dimensions are accurate and the wood properties consistent throughout the bow there is no reason for me to think the design and the actual bow won't very closely match each other in the end.


Mark

[willie]

Arvin,

if you are going to build another and want computer program input, I would be willing to do a follow along that demonstrates how to use visualbow.

we could collaborate your design finetuned with the program, and post the work as we go, all in the same thread.

[Selfbowman]

Willie I Am not sure I’m capable of doing what you are talking about because of my lack of computer skills. I’ve built from architectural plans my whole adult live and can follow plans pretty darn close. That being said I’m willing to give it a go. So far I e found building from force draw curve and bend profile was the easiest for me. Getting close to plan dimensions in thickness and going from there. Being a unbacked selfbow it’s near impossible to get your thickness spot on. You have to be close to the plan dimensions in he beginning to achieve the end results in my opinion . So it has to be a collaboration of dimensions and bend profile and force draw .

[willie]

Arvin,
there was a thread a while back about using computer programs, and I thought a followup workalong might be nice to demonstrate how to use Virtualbow.  My contribution to the project would be......

demonstrate how anyone can test a ripping from the stave on the tiller tree, in order to arrive at more precise numbers to plug into Virtualbow for the actual build.

demonstrate with screenshots how I will plug your design ideas and test results into the program and show how different options or changes will affect the design, say for instance if you want to change limb lengths, widths, recurve, deflex or reflex.
                                                                                                                                                                                                                                                         

I’ve built from architectural plans my whole adult live and can follow plans pretty darn close.

Before computers were used to draw plans, we used to scale from plans to get dimensions that were not specifically noted, the success of doing this depended on the accuracy of the draftsman. Now a days computer drafting has made some things easier and better, but sometimes the way the plans are printed out means problems can be introduced unexpectedly.
I think Virtualbow can generate a force draw curve, but I do not have the technology at hand to print and mail full size bend profile curves. Visualbow will output these profiles at any draw length and actually let you move a slider a draw the bow to any drawlength on the computer screen. and  screenshots can be made and posted  to help "eyeball it" for comparision. Maybe someone with printing equipment available can help if full sized bend profiles are desired.

Anyone that wishs to follow along could load the program on their laptop, but it will not be neccesary for you to do so unless you want to.

Being a unbacked selfbow it’s near impossible to get your thickness spot on

yes, with an unbacked selfbow, the back crown or a rounded belly complicates things. Virtualbow was primarily developed for use with FG laminated bows and can easily work without the FG lams so long as the limb crossection remains retangular. when crowned backs and bellies are part of the design, some adjustments will need to be made in the calculations thus starting thick will be prudent.  how much extra thick will depend on our success at estimating the "adjustments". perhaps some additional work with the proposed test specimen will get us fairly close.

[Zugul]

I would really like a thread like that, it would help me understand better how to design a bow specifically for any stave