deflex and reflex theory

[avcase]

Half bow,
Good diagram!

If the leaning tower with the string laying along side it is stiff, then it’s momentum will still be forced down the string. In the case of a bow, the forward momentum of the limb is transferred to the arrow as long as the bow/ tower does not buckle, and the string can take the load.

A bow shouldn’t experience a sudden stop at the end of the return stroke.  The limb tip of a very efficient bow will typically start slowing down in the last 1/3rd of the return stroke.  Because of the changing string angle, the arrow will keep gaining speed and the limb continues to slow down until the bow reaches its dynamic brace height and the arrow nock separates from the string. So it is more of a tug on the string over a period of time rather than sudden stop at the end.

Alan

[avcase]

The problem was that efficiency was very poor because the string hadn’t no leverage on the unsupported limb and all that’s forward energy remained in the limbs at the end of the shot.

Alan, could you elaborate that topic? I can see what is happening (have made a few too-much-reflex-*****bows) but I can't get what is science behind low efficiency and flip-flopping. What exactly means "no leverage on the unsupported limb"? Why is so much limb's forward energy remained in the limbs? Every bow has moving limbs, which have some forward (in direction of arrow) kinetic energy and momentum - but what is the process of energy transfer to the arrow?

The bow design with the best force-draw curves are extreme full-working recurves.  This requires the entire length of the limb to flex as the bow is drawn back.  But this flexibility doesn’t work as well on the return stroke unless the limbs can be made from a zero mass material.  What happens is that the flexible limb will buckle and oscillate on the return stroke in reaction to the increasing string tension. To use Halfbow’s diagram of the leaning towers, it is like the diagram of the string laying against the tower and trying to hold it in place, except the tower is made of rubber, and it buckles under the tension of the rope.

The limb flapping and vibration is visible after the arrow has left the bow, but this is just a symptom that indicates some energy remained in the limbs, not the arrow.

Alan

[Badger]

We have enough guys working on fast boats right now That'll Walk the talk type event would be very interesting. Suppose we set a date approximately one year from now at one of the big gatherings Maybe mojam. We set up a shooting machine and address could mail their bows in ahead of time. My guess would be Rd recurves would win which speed between 188 to 190. I would guess that straight reflex bows would be slightly behind them maybe two or three feet per second. This would be for laminated bows and I would guess that self bows would be about 5 feet Behind These

[sleek]

We have enough guys working on fast boats right now That'll Walk the talk type event would be very interesting. Suppose we set a date approximately one year from now at one of the big gatherings Maybe mojam. We set up a shooting machine and address could mail their bows in ahead of time. My guess would be Rd recurves would win which speed between 188 to 190. I would guess that straight reflex bows would be slightly behind them maybe two or three feet per second. This would be for laminated bows and I would guess that self bows would be about 5 feet Behind These

Count me in.

[willie]

We set up a shooting machine and address could mail their bows in ahead of time. My guess would be Rd recurves would win which speed between 188 to 190. I would guess that straight reflex bows would be slightly behind them maybe two or three feet per second. This would be for laminated bows and I would guess that self bows would be about 5 feet Behind These

Steve, with that little difference in FPS using a shooting machine, wouldn't you want to compare cast distance also?

[sleek]

We set up a shooting machine and address could mail their bows in ahead of time. My guess would be Rd recurves would win which speed between 188 to 190. I would guess that straight reflex bows would be slightly behind them maybe two or three feet per second. This would be for laminated bows and I would guess that self bows would be about 5 feet Behind These

Steve, with that little difference in FPS using a shooting machine, wouldn't you want to compare cast distance also?

That's an event on it's own already, and more to do with archer and arrow. This would be pure power if the bow, and I'm ALLLL about that

[Tuomo]

Thank you Alan, Halfbow, willie and so on – I got it!

[Selfbowman]

Guys I built a reflex glass bow to the same design as my pyramid selfbow design.it was a dog! So my point here is the material must play into the equation. That being said in a osage pyramid bow which you have close to perfect deminishing mass there is virtually no shock. I’m thinking distribution of the mass is important as  the reflex or deflex.  Arvin

[Stick Bender]

I agree with Arvin distubution of mass is key all of my D/R glass & carbon bows are pyramidal front view !

[willie]

That's an event on it's own already, and more to do with archer and arrow.

I should be more clear with my suggestion, Sleek.

When I mention cast, I am not proposing a flight for max distance evaluation.

The cast of the arrow could also be evaluated in a shorter distance, say 50 or 75 yards or so. Maybe looking at the arrow drop at the target, when the machine is set for level or 5 degrees above the horizontal (for instance). Speeds would still be recorded directly in front of the machine but observing downrange performance could tell a bit about "bow caused"  instability factors in arrow flight. Just move the backstop further back to enable more observations. Admittedly, this would not account for different arrows abilities to recover differently, but if a shooting machine is to be used and release factors will be minimized, so could arrow differences also if a few modern type arrows were for the testing.

I have a project where I intend to use one inexpensive guitar pickup at the target and another at the machine to help determine actual time of flight. The distance divided by time would yield an average velocity over a practical distance

[Halfbow]

We have enough guys working on fast boats right now That'll Walk the talk type event would be very interesting. Suppose we set a date approximately one year from now at one of the big gatherings Maybe mojam. We set up a shooting machine and address could mail their bows in ahead of time. My guess would be Rd recurves would win which speed between 188 to 190. I would guess that straight reflex bows would be slightly behind them maybe two or three feet per second. This would be for laminated bows and I would guess that self bows would be about 5 feet Behind These

I'd join in!

[DC]

We have enough guys working on fast boats right now That'll Walk the talk type event would be very interesting. Suppose we set a date approximately one year from now at one of the big gatherings Maybe mojam. We set up a shooting machine and address could mail their bows in ahead of time. My guess would be Rd recurves would win which speed between 188 to 190. I would guess that straight reflex bows would be slightly behind them maybe two or three feet per second. This would be for laminated bows and I would guess that self bows would be about 5 feet Behind These

I'd join in!

Me too

[bradsmith2010]

Im pretty sure I read a post by Marc that white lightning shot 190,,reflexed no deflex,,
do you think the reflex deflex has a speed advantage in general,, I could be wrong I am going by memory

[Stick Bender]

Im curently building a reflex only , retro flip tips 57" osage/sinew Laubin inspired bow  Im induesing  4" of reflex to start & going to take tiller out to at  least 28"-29"  I guarantee its going to stack more then if it was a D/R but I will let you know on performance I could make both types to compare its really the only way know vs a paper bow , we need working examples !