Limb pocket angles for 3 piece take down

[Jacko]

I have laid up some limbs for a 3 piece takedown recurve using 1 1/2" laminations I ground myself . Am aiming for 45# @ 28". I wont a 56"  bow for tight hunting situations I often put myself into .

Now the crunch - I have drawn up plans for a 16" riser . Its limb pockets are set back 1/2" from the the extremity of the riser with the intention of creating a more forward handle thats also features a offset grip for a better pointing bow.
I borrowed a mates Form he made using Binghams 58" - 62" 3 piece takedown recurve plans . I do not want too use Binghams 19" riser design , I want something more of myself invested in this bow . I need to trim about a 1/4" from the limb butt and will be lopping at least a couple of inches of the original Bingham form limbs , then glueing on a overlay to stiffen the recurve into a static tip

Can any of you more experienced fibreglass lam bow makers advice me what is the best limb pocket angle to use ? if its best to stick with a 21 degree limb pocket angle or is it better to reduce the angle to 18 degree's perhaps ?
Would I be better served to go with a shallower angle considering I have in mind to make a set of deflex reflex longbow limbs for this riser in the near future?

I appreciate any advice on this as I have lots of experience with selfbows and bamboo backed bows and none with making short 3 piece takedown glass bows

regards Jacko

[PV]

Depends on what you want the bow's profile to look like. Lessening the angle will put the tips further forward. If you are going to take 2" off the tips the 18 degree angle will put your tips closer to the original profile.Your going to lose a bunch of recurve lopping off the tips if you didn't move the wedge further up the form.
Conversly for the future R/D longbow limbs the 21 degree riser will put more deflex in the bow.
Paul

[Jacko]

Ok PV I see the point on cutting 2" off the recurves now that I have laid them out on the floor against a paper template of the riser I designed .

I see your point on sliding the wedge up the form - hindsight is a wonderfull thing . I know for the next set of limbs now . Ah well I'm stuck with what I got this time round

I am not after a fast bow just something that is smooth , stable and forgiving as I can make in this length .

Measurements are with a 21 degree limb pocket angle at the moment .

If I trim a 1/4" from the limb butt and clean up the tips loosing a 1/4" from the tips the end of the recurve will be 2 1/2 " in front of the riser .

unbraced length between the recurves is close to 58"

I am trying to minimise the brace height [ lengthen my power stroke ]. I am guessing right now that the bow would require quite a high brace .

Would a good approach to arriving at a reasonable limb pocket angle be too determine a distance in front of the riser I want the recurves to be , balancing the amount of string tension and how twitchy a bow this short would be to shoot .

Going off my experience making reflexed selfbows and boo backed bows they get twitchy with more than 2 inches of unbraced reflex . Is it reasonable with a fibreglass laminated recurve this short to aim for 3 to 4 inches of unbraced recurve in front of the riser .

Any one with a 3 piece takedown around the 56" to 58" length please chip in with your impressions

regards Perry

[PV]

Your recurve limbs will handle reflex better than your reflexed self and BB bows. The consistancy of the lams and glass makes for a stable limb. What I've done when experimenting is to glue up a few risers and change the angles,lenght,profile,etc.My 56" recurve is a forward handle,21 degree angle,18" riser and 1 "shorter limbs(moving the wedge up 1") This puts the tips about even with the front of the riser.Stable,forgiving and about 5 fps slower than the straight riser with the same limbs.

[Jacko]

Thanks for you insights PV , you have turned a few lights on . I will follow your advice with moving the wedge up the form and lay up another set of shorted recurve limbs after I have finished this bow with the riser I've drawn up and see how the bows profile and performance changes. Might leave the recurve / longbow limbed bow till I have a bit more knowledge

While fibreglass bowmaking seems to be largly a mathematical formula I am discovering success is all about how you apply it .

regards Perry

[PV]

One of the benifits of 3 pc glass bows is once you make the limbs you can experiment with the side profile with the same set of limbs without much concern about ruining them as you would with wood. The glass can take a considerable amount of stress and return to the same shape. Good luck Perry and keep us posted
Paul