Primitive Archer
Main Discussion Area => Bows => Flight Bows => Topic started by: willie on March 07, 2018, 05:47:29 pm
-
Here is a couple of pics of a fixture I am building for some Bodnik Mohawk Hybrid takedown limbs. It still needs an arrow rest, a way to draw the mechanical release back and to be mounted to a stand at the range.
The purpose of placing the limbs in a fixture is so that different arrow designs can be shot with some degree of repeatability. Limb spacing and angle of deflex is adjustable for further evaluation of any particular arrow.
About 60 pounds of mostly inch and an eighth plywood. hope this pic is better.
-
Wow Willie .....your really spending a lot of time designing and building some mighty fine fixtures.......But I would love to see more bows that you build. Do you make selfbows?
DBar
-
That is cool Willie!
-
Yea DBar.....I sent him 2 very nice staves.1 osage and 1 hickory.Figured I'd see a bow built on here from that.Looks like a good set up though.Took some well thought out planning.
-
Great set up.
Handy for plotting the FD curves with the various configurations to :)
Not so useful for wooden limbs tho' >:(
Del
-
I think that’s will work for a consistent arrow launch platform. Do you plan to use a small winch to draw the bow? Do you want the thing to fire automatically at a pre-determined draw length, or will you fire it manually? What is your plan for the arrow rest?
You might consider adding an extension out the front to mount a chronograph too.
Alan
-
I hope there will be lots of snow and time to work...great setup! Maybe a high speed camera?
Is it to compare speed of different arrow designs only? Or also arrow flight and take off, than maybe a mechanism to simulate finger release?
Jan
-
Not so useful for wooden limbs tho' >:(
Perhaps not, Del. It is primarily for experimenting with different arrows, but I did have a plan brewing about putting some shorter billets together into a sort of three piece all wood semi-takedown.
Alan, a chrono and some sort of steady draw + auto-trip release is definitely in the making. Haven't given the rest too much thought yet, but the space between the limbs is wide open to possibilities. I suppose that adjusting the height or centershot can be used to fine tune the arrow spine needed.
Is it to compare speed of different arrow designs only? Or also arrow flight and take off, than maybe a mechanism to simulate finger release?
Yes, not only to compare initial speed of different arrow designs, but hopefully a way to evaluate cast and stabilization with arrows of identical weight, but different fletchings, FOC and spines, etc. I am sure the hard part for me as a archer will be seeing just what the difference is between the machine and my fingers once I put the limbs back on the factory riser.
-
Willie, I'm curious why you made it to just hold the limbs rather than the whole bow. Were you planning on experimenting with deflex angles?
-
Don,
not only the deflex angles, but I can move the limbs closer together or further apart by sliding the aluminum mounts in the unistrut. this will hopefully allow adjustment in the poundage, string tension at brace, and draw length, so that I can quantify how a specific arrow responds.
The pics below show the factory bow profiles. The mfg makes some surprising claims and warranties about the limb construction and durability with light arrows. I probably have written too much about them on account of their forbidden f-word construction. This project is really about wood arrows.
-
Willie is that for flight shooting ? I have a three piece I would maybe like to shoot at the flight shoot but don't know if there is a class for the three piece Longbows? Nice set up by the way. Arvin
-
Willie is that for flight shooting ? I have a three piece I would maybe like to shoot at the flight shoot but don't know if there is a class for the three piece Longbows? Nice set up by the way. Arvin
I had built a takedown bow a number of years ago that met the rules for primitive flight. It is really challenging however because metal fasteners are not allowed. On my primitive takedown, I bound the limbs to a wood handle using numerous wraps of flax twine, but it was only good for a few shots before the limbs would start shaking free of the binding.
Takedown limbs for the modern Longbows were disallowed retroactively after my oldest daughter showed up with one and exceeded the standing record by a large margin. It took her 11 years to finally repeat that distance with a single piece bow. Under the present rules, 3-piece bows with bolt down limbs are shot with the Modern Field recurves.
Alan
-
I had built a takedown bow a number of years ago that met the rules for primitive flight. It is really challenging however because metal fasteners are not allowed. On my primitive takedown, I bound the limbs to a wood handle using numerous wraps of flax twine, but it was only good for a few shots before the limbs would start shaking free of the binding.
Takedown limbs for the modern Longbows were disallowed retroactively after my oldest daughter showed up with one and exceeded the standing record by a large margin. It took her 11 years to finally repeat that distance with a single piece bow. Under the present rules, 3-piece bows with bolt down limbs are shot with the Modern Field recurves.
Alan
What a pity! so bows like this one aren't even considered primitive? http://www.primitivearcher.com/smf/index.php?topic=38514.0
-
What a pity! so bows like this one aren't even considered primitive? http://www.primitivearcher.com/smf/index.php?topic=38514.0
Yes, this bow seems to meet the US Primitive Flight rules for a complex composite. It uses wood dowels and looks like natural material binding for the takedown feature. It does not meet the Modern American Longbow rules however.
Alan
-
Willie is that for flight shooting ?
yes, I hope to be able to shoot at full range, and maybe also come up with some kind of backstop/target that can gently stop a fragile flight arrow at 75 yards or so.
maybe a mechanism to simulate finger release?
Jan, the more I think about your suggestion, the more useful something like that seems. Did you build a release to do that on your machine? I would be interested in how it works.
-
Wille I have about 20 sets of real clean drops from roughing out my long bows. So if you need to build some three piece take downs let me know. That’s my plan for them . Probably 26-29” long. Arvin
-
Arvin
not sure what you are calling drops. Limbs without handles? limb length staves?
It was my plan at one time to build risers for limbs that were pretested in the fixture. Of course, the handle needs not to be anything other than functional. and the mounting of the limbs could be permanent, semi-permanent or even be interchangeable if one desired. A good performing set of limbs might deserve a dedicated riser, and could be permanently glued and/or pegged and/or lashed. primitive qualification seems possible.......
I actually have no plans at present, but please PM if you have ideas :)
-
Willie you can buy a mechanical release designed for the thumb which is a push instead of pull, a little easier to adapt to shooting machine
-
I got an old trigger style one modded just like that, reversed the trigger. and just need to get away to the shop more often to work on this project. at the shop which is 70 miles from home, I can open the garage door and shoot 500 yards from inside the shop
-
Another option is to use a rotary latch. These are inexpensive, extremely durable, and usually very easy to adapt to be triggered by an adjustable finger. I have used one for years on bows up to 300 pound draw weight.
Alan
-
Alan would it resemble a door latch on a truck?
-
Another option is to use a rotary latch. These are inexpensive, extremely durable, and usually very easy to adapt to be triggered by an adjustable finger. I have used one for years on bows up to 300 pound draw weight.
Alan
the rotary latch idea seems like something to look into if possible, was hoping alan might come back with some more details or a pic for badger......
-
Allen works for Freightliner as an engineer, I used to be a freighrliner mechanic so I know the latches very well.
-
This shows they type of rotary latch I would use for a shooting machine. I mount it to a plate that slides on a piece of aluminum T-track. I hook the string on the little notch that I cut into the latch claw, and draw it back until the trigger lever contacts a finger on the shooting machine. I attach the trigger finger to the same piece of t-track so I can slide it to the desired draw length. As soon as the latch lever makes contact, it lets go. It is very repeatable and even a light duty latch like this will last for many thousands of shot cycles.
Alan
(https://live.staticflickr.com/65535/49589622666_3bd270b8d7_w_d.jpg)
-
thanks for the print, Alan
sliding in a track will work better than what I have going now
-
I think a couple more pictures would help. If you really want to get fancy, you can pick up a piece of “8020” T-track extrusion, and get one of the 8020 linear slide bearings to attach the rotary latch release to. 8020 is like the ultimate lego set for big kids. We use it all the tine at my work to quickly construct all kinds of test fixtures. I use it for the shooting fixture for my bows when I test arrow performance at the Alvord dry lake bed every summer.
You can probably come up with modifications to the latch to simulate a finger release also, if that is important. I imagine you could fasten or weld a more blunt “hook” that would give more of a sideways deflection of the string upon release.
Alan
-
alan.
like this for the square 4 slot tube? https://www.amazon.com/80-20-Double-Flange-Bearing/dp/B006YVZ31K/ref=pd_day0_hl_328_2/147-7805217-4947045?_encoding=UTF8&pd_rd_i=B006YVZ31K&pd_rd_r=0bf6bbf4-2474-4e22-9a8d-a30431a83b24&pd_rd_w=gcVct&pd_rd_wg=YG7BQ&pf_rd_p=531c5da2-92c8-47a3-8df6-cb5fa8f00603&pf_rd_r=HZMHNHVX4YN0G0X1KV7G&psc=1&refRID=HZMHNHVX4YN0G0X1KV7G
that 80/20 kit looks like the way to go, but so far I have just been using scraps of plywood and unistrut, you got me thinking though. right now the snow is deeper than the arrows are long, so Its a good time to work out some designs on the sketch pad.
-
Those are not cheap, but they are sure nice and smooth and used for very precise and durable sliding fixtures. I made my own t-slot slide by milling out a piece of HDPE plastic using my table saw, and it works pretty well for my needs. Will get a picture uploaded.
Alan
-
Thanks Alan for the information! Rotary clutch seems to be nice idea and especially the 8020-system. I think that I will make a new shooting fixture. It would be nice to see your shooting fixture, because I think it is quite well design.
-
I love the 8020 system. I made my endless loop string jig, bow weighing fixture (for our flight shoot events, and many other things out of this. My regular shooting machine is all in pieces right now, but I will need to get it operational in the next couple of months in order to test some new Flight bow designs before I send them out to the archers who will be using them. I rarely re-assemble the shooting machine the same way twice. I configure it on the fly depending on the types of bows I’m testing, and the types of tests I am performing. For example, it will be configured a little different for test shots in the field where I am more co corned about measuring arrow performance, Vs. tests in the workshop where I am chronograph testing the bow.
Alan
-
Alan - some photos of your fixtures (all of them....) would be nice! No need to reinvent the wheel... What works and what doesn't?
-
I would love to see pictures of everyone's bow clamping mechanism. Mine moves a bit between shots. I made a rolling block type release that is serving me well.