Flight Bow Shooting Machine

Cool stuff....

https://sites.google.com/site/technicalarchery/technical-discussions-1/shooting-machine

You said it was in 2 parts, where does the black & white furry piece go?

"where does the black & white furry piece go?"

I'd bet: Anywhere it wants to go.

I thought that was the projectile.

Certainly not where you think it should go, or want it to go.

Those have minds of their own.

So, apparently, do flight arrows.

Yes, it always amazed me that, given the amount of distortion in the arrow at the start of its flight, they can be placed with any sort of accuracy.

Wanna hear a nock nock joke?

nock, nock...

Viking: Who's there?

Viking too: Another Viking!

Loose!

Coming to an engineering forum it is not surprising that someone would suggest solving your consistency problem with a degree of automation. Triggering a solenoid to activate a pawl that releases the draw fingers should greatly reduce the discrepancies in draw weight at release. The solenoid could be activated by a limit switch that can be adjusted to be operated by the draw finger mechanism at a set draw distance or by a tension type load cell mounted in the draw string which activates an output relay in the load cell amplifier on reaching a preset load.

A suitable solenoid is available for about £15 ($22) Making a pawl to release the draw fingers would be more expensive but if you know any clock repairers one could be fabricated from standard or only slightly modified parts. A waterproof V3 limit switch costs approx £8 ($12) and just needs a length of aluminium curtain track and a block that can be locked onto the track at any fixed point to create the adjustment mechanism. Create the block from a standard fixed end for the track. The drawback (no pun intended) of using a limit switch is that the draw weight at any fixed point will change according to temperature and humidity. The load cell overcomes this problem at a higher cost. An S type load cell will cost £125 ($190) and a DC powered amplifier with digital readout, keypad and simple to adjust set point relay outputs £260 ($390) in an IP66 enclosure. Prices ex works UK. Accuracy + 1lb. Add to that a battery for use in the field and a bit of simple wiring. I just used one of my regular suppliers to get prices but there will be lots of suppliers close to you. You can get cheaper kit from the Far East at your own risk.

Yeah, but I made it using stuff I had lying around, cost nothing and is simple, thus reliable. It is designed to have some flexibility as an archers arm certainly does.
Simplicity is always my watchword (and being a cheapskate )
Del

Yeah, but I made it using stuff I had lying around, cost nothing and is simple, thus reliable and delivers inconsistent results. You didn't say CHEAP!

Revised solution. Go to a boot sale and pick up 9 volt electric door chime, they sell for about £1 but if you haggle you should get it for 50p. Canibalise it for the solenoid. Lubricate the end of the rod that hits the ringer. Mount it on the upper side of the slide carriage so that you can slip a loop of string under the rod, over the draw string and back under the rod. When the chime is rung the loop slides off the rod and releases the draw string. If you're lucky the chime will come in a box tied up with string, you can reuse that to reduce cost. To make a switch push two metal drawing pins into the lower side of the carriage of your machine. Fix a third piece of metal to the stem of the slide with an elastic band for easy adjustment. As the carriage moves back the third piece of metal should short out the pins. If the chime comes with a door push button, they often do, use that in place of making a switch and activate it using a piece of wood elastic banded to the stem. Tape a PP9 battery to the body of the door chime. Wire from the battery to the switch to the chime and back to the battery. all close to each other on the carriage. Pushing the spikes of the pins though the wire is usually enough to make a decent contact. If you can find an old door chime by rooting around in your shed you can get the cost below 50p. I classed the battery as an "operating consumable" so didn't include it as a capital item.

I'm afraid you are missing the point.
Do you really think carrying batteries around and solenoid is actually going to give a more reliable solution?
A doorbell solenoid won't have enough force to pull against 100lb of force acting on the side of the rod. I doubt if it would even have enough force to operate the existing trigger mechanism, which is based on a design used for many hundreds of years with crossbows having draw weights of up to half a ton.
"Engineering" doesn't mean "over engineering".
Simple and reliable is what is needed.
Del

I certainly don't know the customs of Flight Archery competition, but a solenoid release doesn't seem to be in the spirit of the sport.

I see that, by definition in Encyclopædia Britannica, aluminum and fiberglass are allowed in construction of the shafts and limbs, so maybe I'm just being a stick-in-the-mud.

You are right... the machine couldn't be used to compete.
I'm only interested in wooden bows (and arrows). I tend to shun formal competition as there is often gamesmanship and a breed of person who is happy if other's lose rather than simply trying to win on their own merits.
Also there are lots of arbitrary rules generally constructed to help certain factions.
The biggest archery organisation in the UK is mostly about Olympic style archery and following the money, their flight shooting classes don't include one for "self bows", (bows made from a single piece wood) which is pretty silly in a country with a heritage of longbows.
I just compete against myself, it being a test of bowyer, arrowsmith and archer.
Del

PS. For the really heavy bows I have a friend who can shoot 'em and I'm showing him how to make bows, passing on the craft :)

Question (showing my pure ignorance) on longbow: Laminated or truly single stick?

I was watching something the other day on a show about weaponry, and they were discussing Mongol weapons.

The re-curve bow used lamination, animal derived glue, water buffalo horn on the interior upper and lower curves, and sinew on the outer extent of the bow. Nock on arrow was usually bone inlay, shaft was bamboo, and projectile point was iron with a taper that fit nicely into the bamboo (drilled as needed), and matched O.D. of shaft closely. Fletching was of available feathers. Eagle?? Goose?? Duck??

They also tested a Mongol baluster, that used three bows, one of which faced backward, and a sort of complicated stringing. The release was string pulled, usually made of the best metal available. The stand was made of local materials anywhere they army was applying siege to a fortress.

I generally make 'em from a single stick, occasionally spliced billets, or a backed bow.
E.G. Yew backed with Hickory is good.
I've also used Yew from the Pacific coastal ranges backed with Yew from the UK .
I have made one tri-lam, Bamboo back, Purpleheart core and a heat treated Yew belly.
https://bowyersdiary.blogspot.co.uk/2017/10/trilam-all-done.html
The Asiatic bows of horn wood and sinew are the pinnacle of bow making, and are on my "to do" list, they can take a year to build so are not an undertaking to be embarked upon lightly!
There were certainly some cunning siege engines constructed... a bit to big for small garden, but I have made miniatures :)
I'm not really into modern materials, but I have made f/glass and Maple crossbow prods and bows.
Del

I think the siege weapons probably accounted for most of the Mongol casualties during siege events, so they are very dangerous to use!

Yew may be from UK, but I R from Texas, if you catch my drift. I am thinking I need to research what the indigenous tribes here used, the Comanche specifically, as they were the epitome (along with the Sioux warriors) of mounted archers.

I have been storing some sticks about 1-1/2" diameter from crepe myrtle bushes here.

They may be unsuitable totally, although when cut they were dead, and had some flex to them. I think they will break easily, unless laminated carefully, and the wood is sawn to eliminate use of the pithy heart.

Osage is prime wood from "over there"
Ocean Spray,Black Locust,Hickory, Hop Hornbeam, all good dunno about Crepe Myrtle
Del

First you have to find that purrfect robotic hand so the draw accurately simulates human draw and release, without any flutter induced by one finger letting go prior to the others.

I don't know anyone not using a three finger draw, at least I do not think I do. I also believe this contributes a lot to bowstring flutter, and along with off line draw, contributes to arrow shaft oscillation across the bow and on into the flight.

Why shoot just one arrow when you can do this:

The wife and I visited an exhibit on the terra cotta army at the science center in Seattle and one of the items there was something similar to what you built. It accepted a standard bow and had a release catch on the back end. The release was a swinging hook to hold the bowstring and a sear with trigger attached that when pulled allowed the hook to rotate and release the string. I could see putting that trigger release mechanism on a shaft that slid in a groove on the bar of your bowholder set up so that the trigger would hit a fixed pin to release. You could get the consistent release at consistent distance. To fire, you pull the sliding shaft back and when the hook release hits the fixed pin, the bow fires.

Yup, that's similar to how mine works... I can see I may have to post more pics
Del

Late one night, at a local watering hole, I think I heard that there might be a ten-foot tall, boney, blue archer, from Pandora, who just might be willing to collaborate, but they use a sort of reverse-wrist loosing style... or so I've heard...

Latest vid of a light weight skinny flight arrow shot from a 120 pound draw weight Warbow!

Years ago (in the 60's) there was a book on archery in the local library about "foot bows". These bows had two stirrups for your feet. To draw the bow you lay on your back with your feet in the stirrups. Of course these bows could be very powerful because your leg strength was used to draw them. As I recall they were used primarily in flight distance competitions. A while ago I searched for information about these odd bows but found nothing. Noticed your blog and thought you would be interested.

Thanks, yes I'm aware of foot bows, I think they are still used in some flight shooting.
Del

Seeing how an arrow flexes when released, I wondered if a non-Newtonian fluid filling would decrease the flexing of the arrow.

I realize this would add weight, but perhaps only a small core of the liquid would suffice and the weight could be compensated elsewhere.

Just wondering...

Custard cored arrows, that sounds good.

I never thought of that!

Perhaps put a porous coating and fill the arrow with seasoning to inject the meat as it is field dressed?

Why not, you can get shotgun cartridges filled with compressed spice pellets, season as you shoot!!

OK, just add a little tenderizer and it will help with that lean game meat toughness.

Or perhaps just the right amount of Thermite so that it cooks the bird before it hits the ground. Very tender since it cooks from the inside out.

You even have a brand name, "Shooting Season(ing)"

Demo that on Shark Tank.

Ok,you started this:Grandpa had a 12 gauge with a full choke and a 48 inch barrel.He had to put rock salt in the barrel ahead of the shell to keep the ducks from spoiling before they hit the ground.

(First liar doesn't have a chance)

This blog got me researching good woods for bows, and I came across China Berry as a good wood. I have plenty of these trees near me; they grow fast and are easy to train.

Perhaps I could train a limb to a bow shape by conforming it to shape as it grows, that way all the grain would be in the same direction as the shape.

This would require patience, but bow smiths are notoriously patient.

"Grow-a Bow"?

Just wondering...

We don't get that growing in the UK.

Yes, you can train a limb to grow to shape, but it's easier to start with a straight piece and heat bend any shape you want.

Del

Would there be any advantage in a grown-to-shape bow versus a heat formed one?