Primitive Archer
Main Discussion Area => Bows => Topic started by: AH on May 11, 2013, 08:25:16 pm
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So, I keep hearing about this computer program called "supertiller". Apparently, people use it to simulate bows and calculate draw weights from dimensions and draw weights at non-full-draw legnths. Does anyone have experience with it, and know where I can download it?
Also, is it really that accurate? ??? I sort of have my doubts.
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??? ::) I'll pass
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Buzz kill.
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Duh............... ???
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I have an exel spreadsheet that kind of does that although I don't think it is the super tiller program. It's extremely difficult to use although I know the creator has made some excellent bows with it. If you're familiar with the red oak bow that demonstrates trapping in TBBV4, that is his bow, David Dewey.
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seems like a lot of work when you can just go make a bow with out all that technical stuff
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There are no shortcuts.
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WOOD IS WOOD
You can't build a bow by dimemsions.
SLOW DOWN ONLY YOU ARE PUTTING A TIME LIMIT ON FINICHING
YOU'LL BUILD BETTER BOWS
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Nothing beats a good pair of hands and eyes to match ;)
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Wood is too inconsistant to be able to predict tiller with a computer program. You can guestimate pounds per inch of draw with wood bows but it is only a guess. If you are working with a FG lam bow you have to predict closely what the lam stack will eventually result in especially if you are manufacturing production bows and even custom bows.
I got into "primitive" archery to get as far away from all that as I could. I use my eyes to determine tiller. In some instances I will use a Gizmo to help with difficult to read tiller and I use a scale to determine weight(lots of you guys know how well my scale works ::) ) but other than that I want to do it all myself. That is the challenge for me as a wood bowyer. I want to get as far away from the "FG mentality" as I can when it comes to my bow building.
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I am working on this fully autonomous computer guided
CNC maching three-dimensional wood printer that can design, build, tiller perfectly, and even shoot a wood bow! No sweat, tears, or blood required! ;D ;D OK, that was a bit much. I agree with what has been said. I don't even understand why some people ask for dimensions on other bows, it just doesn't fit into the way I build them.
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The only way a computer program could accurately predict how a bow will turn out is if it has a built in variable or function that takes into account the quality of the wood. For instance you could develop a standardized test such as the bending test where you take a standard size piece of the log or board that you have, apply known forces and measure the deflection until failure.
From that test you could get a variable or set of variables that could reasonably define the "quality" of the wood specimen. If you then incorporated that into the program it would be more accurate, but it still wouldn't account for the specific grain pattern throughout both limbs.
My guess is that in order for a computer program to have all the necessary variables you would need to spend so much time testing and gathering data about the wood you have that you could have built a bow in that time.
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Right there with you Carson. I keep seeing the same question from guys about limb thickness. I still believe that that is question designed to short-cut the process. Tell me how wide long and thick to make it and I will cut it to those dimensions and presto! I used to think primitive bow making was an old guys thing, simply because it required patience and insight and experience to really be any good at it (things that most young people have in limited quantities to some degree). That's not true. Look at all the really young guys building knock-out bows, so it's for any and all who can appreciate it. For me, a big part of the enjoyment is the element of surprise with every build.
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I htink " super tiller" is designed more for those with an interest in flight bows or otherwise high performance bows. They can build a virtual bow on the computer and make changes to it in an attempt to narrow down a specific design. I think when it comes time to actually build the bow they use the same tecniques we do. I saw a red oak board bow that Dave Dewey built according to his predictions on super tiller and it came out within a few pounds of his projection. I believe it is more of a toy for engineer types. A bit over my head but I find it interesting. As from what I have seen a handbuilt bow will outperform a computer generated bow because of the alowances the computer makes for stress. I think exploring design elements would be its main usefulness.
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Thanks, guys. I thought so.
The thread that I heard of "supertiller" on was some thread discussing the draw weights of the war bows on the Mary Rose...and we all know how finicky that subject is. ::)
I thought from the beginning, "No way this program this program is accurate". because there's always a ton of other factors that a computer can't count for, like wood density, knots, stuff like that.
I very much doubt you could build a character bow, put it's dimensions in the program, and have the same result as the computer would calculate! ;)
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Being an IT guy I hate Computers...
Besides... THIS IS SPARTA!!!
Oops... I MEAN PRIMITIVE ARCHER!!!
:)
-gus
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Sounds stupid to me. Hell i don't even usually measure for length...
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Being an IT guy I hate Computers...
Besides... THIS IS SPARTA!!!
Oops... I MEAN PRIMITIVE ARCHER!!!
:)
-gus
..... :laugh: I remember the old days of DOS 3.1 Computers have their place, but there is nothing better than sitting around the campfire watching the embers and shooting the gossip instead of texting and facebooking...! >:D
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Hell i don't even usually measure for length...
I see you follow the same sort of habit... ;D
That's why I don't buy bowstrings from archery stores anymore. I can never remember the bow's length and then tell the guy at the counter. Just make a flemish twist string and tie a timber hitch at whatever's the right legnth.
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Being an IT guy I hate Computers...
Besides... THIS IS SPARTA!!!
Oops... I MEAN PRIMITIVE ARCHER!!!
:)
-gus
Ha!
(emphasis on primitive)
I'm known as the "paleoman" among my friends, who are all computer people. However, here in the Silicon-Valley area of the CA bay area, it's just about impossible to not have technology exposure.
Don't get me wrong. I like technology. The wooden, bendy kind. ::)
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I wrote this program when I began building bows about ten years ago and have used and tinkered with it ever since. I also make it available for free to anyone who is interested in bow design.
One of the strengths of the program is that it lets me see the effect of changing design characteristics of a bow without having to make tons of experimental bows. It is a very good tool for exploring questions like:
What is the effect of recurve or reflex?
Effect of brace height?
Why are some bow designs more stable than others?
What is the effect of thickness taper on tiller profiles Vs. width?
Where does the energy of drawing the bow go? How much energy makes it to the arrow, how much stays in the limbs? How much stays in the string?
What is the effect of string design on bow performance?
Etc.
What it won't do is build the bow for you. It won't help you deal with knots or construction details. It doesn't know if your materials deviate locally from the average values used for each material type. For example, it won't perfectly predict draw weight because no two pieces of wood are exactly alike. However, it will get you in the ball park. But, the issue is no different with real bows. I feel I could use this program to do just as good a job predicting the draw weight and performance of a historical artifact as building an accurate reproduction.
Alan