250 pounder attempt

[markinengland]

Rudderbows,

I remain interested in how such a narrow bow will reach the weight you want. This might be possible just with Ipe/Boo or Ipe/Hickory but is it possible with Hickory/Hickory?

I don't claim much experience with heavy bows having made them up to 120lb or so but I have found that early high draw weight makes heavier bows harder to pull. A progressive build in weight can be managed better, with weight building in the last six inches or so of draw. A long straight bow helps, perhaps with a degree of set to help keep early draw weight low so you can get it past the "wall". This would perhaps rule out a perry reflex effect increasing the weight and also increasing the early draw weight.

Fancy answering this?

Mark in England

[RyanY]

I haven't built any really heavy bows but I understand what you guys are saying about how this bow needs to be wider to even think about getting to this weight. Now if you try to make a bow this heavy from boo and ipe wouldn't those be the best materials to work with? I'm just thinking that since you don't want to make this bow too much wider that bamboo has enough tensile strength and ipe has enough compressive strength for this bow to be thicker? I don't have any experience with bbi bows but from what I hear bamboo is pretty much the strongest thing you're gonna back a bow with while ipe is equal in its compressive properties. I realize that there must be some flaw in my thinking since you guys haven't said much about just having a thicker cross section. I understand that hickory couldn't probably take the compressive forces of a bow this extreme but why not bbi?

[markinengland]

Ryoon,

I reckon that ipe/boo at about 2 inches wide and somewhere over 80 inches long glued up straight should be a good start to get 200lb plus in as manageable a way as possible.

If it isn't to be drawn by a human but by a machine then it could be made less wide and some perry reflex glued in for sheer performance.

The draw force curve would be interesting to see if the bow is made.

Mark in England

[rudderbows]

Mark, I fully intend on taking your advice to heart about width and Marlons advice about length. One issue I am concerned about is someone getting hurt. I do not want that to happen AT ALL.  Bow stability is important. I think different materials will require different measurements. the thing that I can afford to do is experiment with the different materials on the crank. If it blows on the crank it will miss everyone including myself and employee and the shop Dogs because I am going to have a couple pieces of plywood set up on each side of the crank. . . haha;/. .  Anyways I fully intend on making it a wider and longer. I also know that an Englsih style rounded belly can bend farther  than a flat belly before breaking. My buddy Phil tried some experiments some time ago with this. He simply made flat bows and english style bows and decided to pull them on a pulley system untill they broke. He discovered that rounded bellied bows go 15% to 20% farther before snapping. Maybe thats why the English bowyers made them with rounded bellies. More stable perhaps.
 

Rudderbows,

I remain interested in how such a narrow bow will reach the weight you want. This might be possible just with Ipe/Boo or Ipe/Hickory but is it possible with Hickory/Hickory?

I don't claim much experience with heavy bows having made them up to 120lb or so but I have found that early high draw weight makes heavier bows harder to pull. A progressive build in weight can be managed better, with weight building in the last six inches or so of draw. A long straight bow helps, perhaps with a degree of set to help keep early draw weight low so you can get it past the "wall". This would perhaps rule out a perry reflex effect increasing the weight and also increasing the early draw weight.

Fancy answering this?

Mark in England

[markinengland]

One route to this might be to make an 84 inch 125lb bow. From this you can almost just double the width to get what would be needed for 250lbs. Initially doubled up it would be somewhat over strength but basically in the right ball park so all you need to do is reduce the depth a little which will make it even safer than the 125lb bow was. Experimenting at 125lbs might be a little more manageable and less risky but should give a really useful steer on what is needed for the heavier bow.

Regards,

Mark in England

[Rich Saffold]

I'd make it 2.75" wide, 5/16th" boo backing,and I would r/d with a good bit of deflex just outside the grip.

[rudderbows]

Its going to be a little bit tricky because i would like to meet or exceed the English 8 to 5 rule on this thing. When I show an American archer a 80" warbow they trip on the idea. Especially the guys who are used to shooting a seriously short bow. However, the english war bow concept had very little to do with hunting and had everything to do with heavy flight shooting in the field.  (My buddy Magen wanted to come over here sometime form Holland and hunt wild Hogs with an english warbow of 120 pounds. ) I will keep you posted on results. This next weekend are the first glue ups for the big monster bow. Cant wait to finish the week ion the shop to give it a try.

[Davepim]

Its going to be a little bit tricky because i would like to meet or exceed the English 8 to 5 rule on this thing. When I show an American archer a 80" warbow they trip on the idea. Especially the guys who are used to shooting a seriously short bow. However, the english war bow concept had very little to do with hunting and had everything to do with heavy flight shooting in the field.  (My buddy Magen wanted to come over here sometime form Holland and hunt wild Hogs with an english warbow of 120 pounds. ) I will keep you posted on results. This next weekend are the first glue ups for the big monster bow. Cant wait to finish the week ion the shop to give it a try.

Noone knows what bows were used for hunting in England during the middle ages as no bows exist anymore. However the size of the sockets for big hunting broadheads show that the arrow shafts were thick, therefore the bows were heavy in draw-weight since its difficult to shoot arrows weighing more than 100g and with half-inch shafts from bows that draw less than 100lb.

Dave

[Marc St Louis]

I don't think 2" wide would be necessary for a 200# BBIPE.  I would start at 1 3/4" wide by about 1" thick for the IPE with a Bamboo backing of at least 1/4" thick, a bit more thickness for each part wouldn't hurt.  That would give a thickness of at least 1 1/4" and that should be plenty.  Bracing these monsters for the first time is where it becomes real tricky because you need to make them way over target weight

[Yeomanbowman]

I think I'd use a loose string on the tiller (on stringing nocks) and when its drawn down enough have a brave and well insured assistant place a shorter string on the actual nocks. I'd also tiller it with temporary horn rather than self nocks.  Good luck!

[fusizoli]

Bubinga is  good for that? wow

Good project, will looking for how it goes! It will be a real monster shure

[markinengland]

I have heard different reports on Bubinga. It is pretty but I have heard some say it is brittle and perhaps not best for a failry deep bow section.

[Jude]

Wow, I am late as all get out on this post, but here goes.  Back to the subject of strength, drawing a bow balances the pushing and pulling force.  I see many guys out there benching 500# and more, which is 250#/arm, but I don't see anyone doing dumbell rows with 250#.  Maybe some pros do, but we don't go to the same gyms, so I couldn't say for sure.  A big difference between gym exercises and archery, as well, is the pressure that is applied across the body.  I have had issues for the past 8 months or so with the inside joint of my right collarbone, possibly arthritis, and I really notice that pressure now.  Bench-press and pushups hurt a little, but drawing my 70# bow is downright excruciating.

[Rod]

Interesting that the flat bows blew before the longbow sectioned bows. I might think that this was perhaps due to failure in tension at the cross section corners.
Was this the case?

Regarding the question of hunting bow styles and weights, I believe there is some evidence for "flat" or broad bows for hunting.
Richard Wadge for one refers this distinction in "Arrowstorm" and also I believe cites Gaston Phoebus.
But the extremes of draw-weight would possibly not be regarded as necessary for a hunting bow, though undoubtedly what a competent forester/archer of the time would regard as "easy" might no doubt exceed what many of today's bowhunters would consider practical.

Rod.

[Jude]

I recall reading something in TBB4 about using a rounded belly for some of the weak in tension woods.  The rounded belly would take more set than a square cross section, thus putting the back under less strain.  It likely works the same for a superior wood in a highly strained pattern, like a heavy war bow, since superior wood will usually fail in tension before it fails in compression.