Primitive Archer

Main Discussion Area => Bows => Topic started by: Ricardovanleeuwen on April 16, 2020, 12:46:56 am

Title: Design question
Post by: Ricardovanleeuwen on April 16, 2020, 12:46:56 am
Could lighter draw weight bows shoot arrows faster  then a heavy bow due to theirs design? And wich designs shoot arrows fast?
Title: Re: Design question
Post by: Del the cat on April 16, 2020, 02:27:01 am
Relative to their draw weight lighter bows shoot faster than heavy ones of the same style. E.G A 70# ELB won't shoot twice as far as a 35# ELB
The discrepancy isn't so much due to design, as any design can be scaled up or down...
There is probably an optimum set of dimensions for any design /material, but it also depends on the arrow. So what is optimum for a flight arrow isn't optimum for a 1/4 pound military arrow.
Increasing draw weight generally gives more speed, but you rapidly reach a point where the bow (or the archer) can't take the strain. If the bow is made too long the inertial of the limbs makes it slow... you can swish a short stick through the air quickly... but try to swish a 5' length!
Some designs are faster than others, say a flatbow is faster than an ELB (I'm not saying it actually is) but a porr flatbow wont be as fast a good ELB.
Biggest factor is the bowyer IMO
There are just so many variables.
Del
Title: Re: Design question
Post by: Ricardovanleeuwen on April 16, 2020, 02:51:09 am
Lets say the bowyer is me, A elm stave 65 inch, draw weight 40lb  at 28 with a rosewood Arrow spined to the bow , wich designs have the biggest potential to be fsster
Title: Re: Design question
Post by: Jurinko on April 16, 2020, 03:10:53 am
Yes, efficient 40lb can outshoot overbuilt or set affected 50lb bow.

For high arrow velocities and light arrows you go for light tips and non-working ends of limbs acting as levers like Holmegaard design. For fast heavy arrows you need high stored energy, whole limb doing its share of work like Sudbury bow. For both cases you aim for low set and even slight reflex to have high initial draw and fat draw energy curve. There are great articles on this in TBBs.
Title: Re: Design question
Post by: Hrothgar on April 16, 2020, 06:44:07 am
For a 65" elm stave you can hardly go wrong with a flat bow, pyramid style, and heat treat it. I think it was Badger a few years ago who made an ash flat bow around 40# and set a distance record with it, and distance is a good indicator of speed. There are other variables, like Del said, it depends on the purpose of the bow, etc.
Title: Re: Design question
Post by: PatM on April 16, 2020, 07:34:21 am
Static recurve every time.
Title: Re: Design question
Post by: Ricardovanleeuwen on April 16, 2020, 09:00:20 am
Then ik try Both, and what about mollegabet?
Title: Re: Design question
Post by: DC on April 16, 2020, 09:44:13 am
I'm not sure about a Molle. For most bowyers I think you would find that the tips are actually heavier than a conventional bow. The combination of the second set of fades and the fact that most of us are too chicken to make the tips as light as they could actually be means the the tips work out as heavy or heavier than a conventional bow. I've only actually weighed this on one bow and the molle was heavier. The stiffness of the tips may be someting else.
Title: Re: Design question
Post by: Del the cat on April 16, 2020, 10:22:04 am
I'm not sure about a Molle. For most bowyers I think you would find that the tips are actually heavier than a conventional bow. The combination of the second set of fades and the fact that most of us are too chicken to make the tips as light as they could actually be means the the tips work out as heavy or heavier than a conventional bow. I've only actually weighed this on one bow and the molle was heavier. The stiffness of the tips may be someting else.
Very good point :)
Del
Title: Re: Design question
Post by: Ricardovanleeuwen on April 16, 2020, 10:33:52 am
Ah oke, i got plenty of elm staves  to Risk so i Will deffinatly try It soon, for now i try recurve first ( along with some other bows) i tried to make a form to flip the tips, not sure if this is what It need to be? The tape measure is in centimeters by the way
Title: Re: Design question
Post by: Jurinko on April 16, 2020, 10:57:20 am
Too steep i think, i destroyed half finished bow on less curve. Definitely go with steam, heatgun ain't enough.
Title: Re: Design question
Post by: DC on April 16, 2020, 11:06:24 am
That's a pretty aggressive bend, especially for first try. Just for a semantics lesson, "flipping the tips" is just a minor recurve, maybe a couple of inches(5cm). What you've got there are "big hooks" ;D ;D
Title: Re: Design question
Post by: dylanholderman on April 16, 2020, 11:14:44 am
I would agree with making a milder bend.
My second recurve was a “big hook” recurve and it was a Pain in the butt, tips kept wanting to flip even after I got it braced.
65-70 degrees is what was recommended to me for my next one
Title: Re: Design question
Post by: Ricardovanleeuwen on April 16, 2020, 03:46:15 pm
Ah oke, somewhere on here i Read that a quarter of a Paint can is good, dont know wich kind of cans you have? ;D i already used something a lil bit bigger then that
Title: Re: Design question
Post by: Russ on April 16, 2020, 06:48:04 pm
i think if you did a quarter of that curve it would be good. it just keeps going down farther than you want if you get what i mean
Title: Re: Design question
Post by: Ricardovanleeuwen on April 17, 2020, 04:38:15 am
Ah oke ill try  to make it a bit smoother haha
Title: Re: Design question
Post by: Ricardovanleeuwen on April 18, 2020, 11:01:45 am
Yes, efficient 40lb can outshoot overbuilt or set affected 50lb bow.

For high arrow velocities and light arrows you go for light tips and non-working ends of limbs acting as levers like Holmegaard design. For fast heavy arrows you need high stored energy, whole limb doing its share of work like Sudbury bow. For both cases you aim for low set and even slight reflex to have high initial draw and fat draw energy curve. There are great articles on this in TBBs.
A sudbury bow is like a paddle bow but longer?
Title: Re: Design question
Post by: willie on April 18, 2020, 05:06:20 pm
yes . but it bends very slightly in the hand

https://www.primitivearcher.com/smf/index.php?topic=49412.5 (https://www.primitivearcher.com/smf/index.php?topic=49412.5)

http://www.primitivearcher.com/smf/index.php?topic=35731.0 (http://www.primitivearcher.com/smf/index.php?topic=35731.0)
Title: Re: Design question
Post by: PatM on April 18, 2020, 05:36:06 pm
Relative to the limb thickness it likely didn't bend much at all though.   It was 1 3/16  by less than an inch wide.

  I made a replica many years ago and any bend was not visible and certainly not perceptible in the hand.
Title: Re: Design question
Post by: Ricardovanleeuwen on April 20, 2020, 08:33:09 am
I tried using the caul as shows in the photo, this happend to the plum branch wich wanted to test on, is this bad?
Title: Re: Design question
Post by: DC on April 20, 2020, 09:11:42 am
Is the thin white line a split? How thick is the wood where you bent it?
Title: Re: Design question
Post by: gutpile on April 20, 2020, 09:23:36 am
when bending wood especially into a recurve.. I suggest boiling 15 min per 1/4 of wood to bend.. you will need to use a piece of sheet metal on belly side to prevent splinters... lay it against belly tight as you go for all the bend at once.. no time to waste when you pull out of water.. do a few test runs to make sure everything will fit your caul ... gut
Title: Re: Design question
Post by: Ricardovanleeuwen on April 20, 2020, 12:39:49 pm
The thin White Line is one side of a splinter lifting up. It is about 0.8 inch or An inch. I steamed the whole stave for about An hour and user a leather belt over the belly, could be that i didn't pull It tight enough
Title: Re: Design question
Post by: DC on April 20, 2020, 01:41:43 pm
Fill it with CA and continue :D
Title: Re: Design question
Post by: Ricardovanleeuwen on April 20, 2020, 03:46:59 pm
Should'nt i try to sand It out? It dont apears to be deep, not sure because the leather strap is still partly on
Title: Re: Design question
Post by: Ricardovanleeuwen on April 20, 2020, 05:32:11 pm
Oh and i forgot to mention, i started with the easyest limb.. (lol) this one already had a little bit of reflex and was free of knots. The second limb has a bit of deflex and a knot on the side... How should i do this one
Title: Re: Design question
Post by: DC on April 20, 2020, 06:37:24 pm
Should'nt i try to sand It out? It dont apears to be deep, not sure because the leather strap is still partly on
Don't worry about getting rid of it now. Once the stave starts to look like a bow then you can make it pretty. You might even be able to thin it out enough to get rid of it.
Title: Re: Design question
Post by: Hamish on April 20, 2020, 06:38:49 pm
Its probably asking too much to bend a recurve with a knot that size. You could try it, and it might work. Just be prepared for catastrophic failure.
I haven't done a lot of steam bending, but all the texts stress, using straight grained knot free wood. Good luck Bud, I'm hoping for your success.
Title: Re: Design question
Post by: DC on April 20, 2020, 06:55:03 pm
If I'd known this knot was here I would have suggested making a straight bow. In my experience you won't get a usable bend with that knot there. It won't bend where the knot is mainly because it's too thick and if you thin it out it will probably break. Can you shorten the bow enough to eliminate the knot? If not I would suggest straightening out the other end. I will only recurve almost perfect tips. Look at the picture and how uneven the curve is and how big the knot is. I should have left this one straight. This is also plum.
Oh also I'm not sure how much good your leather strap is doing. The reason the strap is there is to stop the back from stretching. Leather has too much stretch for that job. Thin steel is what you want.
Title: Re: Design question
Post by: DC on April 20, 2020, 07:00:38 pm
If you decide to shorten the bow don't cut the knot off. Cut about 10-12mm past it. The last 20-25mm of the recurve doesn't bend much anyway :D
Title: Re: Design question
Post by: Ricardovanleeuwen on April 21, 2020, 12:46:03 am
The Total lenght right now is 158cm wich is 62 inch, if i would shorten It to 20mm past the knot It Will be 150 cm wich is 59 inch. I dont have a draw lengt neither a draw weight in mind as i would also like to have a short draw shortbow or annything, if It end up as a Shooter im happy enough
Title: Re: Design question
Post by: gutpile on April 21, 2020, 07:41:37 am
I would boil it next time.. bends much easier.. apparently strap wasnt tight enough on belly.. or wood not steamed enough.. I've had splinters bigger than that .. you can leave it as is ..if thick enough to not bend .. static.. working recurves eventually pull out .. if it doesnt bend you could try to sand out but keep it stiff... as to not bend when full drawn... I usually do my bends with 3/4 thick tips... boil 45 min to hour.... just tips not whole bow... my curve is pretty radical too... gut
Title: Re: Design question
Post by: BowEd on April 21, 2020, 07:48:03 am
Hi gut.Show us your boiling set up sometime.
Title: Re: Design question
Post by: gutpile on April 21, 2020, 08:33:51 am
Hello Ed.. you posted some fine bows lately... not a great pic but you get the idea... gut
Title: Re: Design question
Post by: gutpile on April 21, 2020, 08:37:12 am
here it is after curves are done.. gut
Title: Re: Design question
Post by: BowEd on April 21, 2020, 04:56:37 pm
Sweet bow....thanks....I thought the method might look something like that but was'nt sure.We've got some pretty inventive people on here.
Title: Re: Design question
Post by: Ricardovanleeuwen on April 23, 2020, 10:08:21 am
Aaaaaand It broke on the knot, its. Oke i splitted a half plum log in quarters so no löss today haha.
I really want to try a recurve, what Wood would you suggest for first try? I got a Apple branch here wich seems to be oke? Its 2 inch in diameter or would this little thing on the end also be a problem? (2inch from end)
Title: Re: Design question
Post by: Ricardovanleeuwen on April 23, 2020, 10:27:50 am
Its 62 inch by the way
Title: Re: Design question
Post by: PatM on April 23, 2020, 12:30:19 pm
Elm is likely the  best wood to experiment with recurves.  Or make some recurved 
 elm pieces and splice them into your apple or plum  staves.
Title: Re: Design question
Post by: Ricardovanleeuwen on April 23, 2020, 02:02:39 pm
I think splicing is next level for me, does the diameter matter when making An elm recurve? I have a bumpy 3 inch a 2 inch and a 5 inch but the stave is really thin and wide
Title: Re: Design question
Post by: PatM on April 23, 2020, 02:59:08 pm
Splicing is nowhere near as complex as it's made out to be.  It's not something you will get prepared for any other way than just doing it.