Jeff Jouett, who used to go by the handle, InitialImage, designed a really curvy form for a reverse handle longbow and gave me the form. I don't think he actually made a bow out of it himself, but we were both curious to see what would happen, so I made a bow. I had some difficulties with it. I had to make the string about two inches shorter than I normally would for a longbow just to keep it strung right, and now it has a large brace height. I explained the problems in this video:
So I'm curious what you think. Do you think using parallel lams instead of tapered lams would improve things? What about just making it shorter? Or do you think we should just give up on this form because it has too much curve?
I'll post some stills in case anybody doesn't want to look at the video.
It'll do it on either side, too. You can just kind of hold the string and make it flip to the other side.
The only way I could get it to not do that is to put a shorter string on it, but now the brace height is nearly twice what my brace height usually is. When I hold the bow, the string comes up almost to my elbow.
No expert here But I'm thinking your form might make a 58" bow.. maybe you can cut some shallow nocks at 60" and see if it helps, if not then try at 58".. your gonna gain a bunch of draw weight cutting it down but you should end up with a shootable bow. I'm thinking the design may be to radical for a 64" bow no matter what taper you use.
No expert here But I'm thinking your form might make a 58" bow
Funny you would say that, Robert. I showed this video to Jeff, and he said he designed the form for a 58" bow. Don't you think it would probably stack at that length, though? The riser is 18", and if I make it any shorter, there'll be a little gap in the form. But if I don't make it shorter, I'm afraid the bow will stack. I think I may cut it down to 60" and see how that works. I can reduce the draw weight some and make it shootable.
Not sure about stacking, you may have to play with taper rate? If you have a gap in the form you can add some filler to the top piece of the form. I have used risers from 18 to 21 inchs (fade tip to fade tip) in this 64" R/D bow with out having to adjust the form and I use a 003/inch taper rate. maybe some more experianced builders will find this thread and offer some sound advise.
Sam, I can't believe you had the kahoonas shoot that thing! It's crazy to me that you can do that to the limbs and it still shoots! My feeble mind thinks a shorter string or shorter limbs is what you are going to have to do and live with the high brace height. Wouldn't a reverse handle naturally have a higher brace height?
I'd take a couple of inches off both ends and see how it behaves as a 60"er. Stacking shouldn't be a problem with that taper- the weight gain from spiking might be though.
bodork, if you saw the video, I did put a shorter string on it before shooting it. The shorter string kept it from doing the weird thing, but the brace height was nearly to my elbow.
The consensus seems to be that I shorten the limbs, which is what I plan to do. I'm going to take it down to 60 inches. I think I can reduce the weight some by sanding the fiberglass and narrowing the limbs.
cut an inch off of each tip and try it.; You either have to reduce the reflex or add taper plus a power lam to make a design like that work. You have to get the mid limb bending fast enough to stabilize the limbs. What you have is called verticle instability big time. I would keep the taper rate you have if it truly is .004 per inch, add a 4 inch tip wedge and extend the fades by adding a power lam that extends three inches past the fades from .060 at the tips of the fades to .000 at the end. Working area that is free in that limb should probably be in the neighborhood of 15 inches or less in a 64 inch bow. Commensurately lower as you drop in length. This is called research and development and is one reason that bowyers get good money for good designs. Sometimes when playing with a radical design you can mess around with it a long time and spend a lot of money with no return.
You could recut the bottom from about midlimb to about the top corner( considering bow length desired). Then glue or screw the cutoff to the top part of the form, it doesn't have to be perfect where the hose lays.
Then you will have to determine how much taper, width , etc the new form wants.
Neat idea, Kennym. I hadn't thought of that. I shortened the bow to 58" today, though. I'm going to see how that works out. The new tip overlays are curing right now, so it'll be later in the week before I retiller it.
Here is the end of the story. I cut the bow down to 58". When I strung it up, it was 70#. I tillered it down to 54#.
The limbs are still noodly with a low brace height. The string on it in the picture stretched a little before I took the picture, so the final brace height will actually be a little higher than this. It's an improvement, though. The brace height necessary to keep it from noodling isn't as high as it was before.
I won't be making any more bows from this form, though.
I may be way off here and perhaps Sixby could chime in here... But why not cut the form down and make a recurve out of it by flattening it up a lot off the fades and put a tighter hook on the end... This would force that limb to bend more in the middle and do it without power lams or tip wedges. I am thinking a Hoots like design here. Just make a new top piece for it. Drop the taper to .001 or .015 max.
I would side dress the top limb until I get the tiller right. Right now your top limb is overpowerig the bottom limb. Use a long sanding block with 100 grit and stroke the limb from fade to tip 20 times on each side and check. When you get to where the top limb , measuring at the end of the fades is plus 1/16 stop and set the brace at about 7 1/2inches and go shoot it and see how it shoots. Do not tiller the top limb over plus 3/16with that design. You can make a good bow out of what you have. If you use a .050 to 0 , five inch tip wedge and go to three or four thousands taper you will move the working area out to the tips and may even end up with an exceptional bow/ JMHO.
Before you toss the mold, I really think youshould try another with longer fades and tip wedge. I have built some radical carbon longbows with very thin limbs but they are very stable using the same techniques and explained by Sixby. He knows more than I'll ever learn so when he says "try this" I listen.
Steve, how's that? Now it's got a 1/8" positive tiller (measured where you see those twisty ties) and a brace height of 9 inches. No noodling, even when I press on the string.
Thats what it should look like. Now increase the taper so that the outer third of the limb bends a bit quicker and you will get the same thing at a lower brace height. However you do now have a bow but with a bit much brace height. you need to work on getting that profile with a brace of about 7 inches/ Be sure to use the tip wedges so that although the outer third bends more you will still retain good string angle and not stack too quick.
