how much faster is a recurve than a strait tip bow?

[PatM]

Yes and outlier statics will shoot correspondingly faster as well.

What are outlier statics?

Outlier as in above and beyond the norm.

[BowEd]

I realized that from shooting a composite bow I made some time ago.Getting the most fps out of a pound of draw weight.

[willie]

Yes and outlier statics will shoot correspondingly faster as well.

you are referring to static recurves when you say "statics", Pat?

I think some of the mechanics described in this thread could be be for straight limbed statics,  and then there are additional benefits for recurving the static tip? (most likely having the tips further forward than in the straight version?)

the string angle thing being a different effect, most useful for shorter bows?

too much being discussed all at once possibly?

[PatM]

Yes. Apart from stiff handles I can't imagine what else it would apply to.

I can't honestly tell a difference between an angled or a curved static tip if the tips end up in the same relative position and the portion is the same length.

It may register on a measured force draw but  the feeling to the hand and arm would be hard to discern.

[Badger]

OK I'll say this anyway in comlpete honesty.A straight limbed sapling flipped tip[not really a recurve] limbs a bit slightly reflexed bow[total on bow 2.5" NTN]I showed some time ago called a wiggle handled osage rawhide backed shot into the low 180's /high 170's with a 10 grain arrow when fresh before 200 arrows through it.48# @ 28".My arrows can't be overdrawn.The nock throat and back end of field point are exactly 28".Bow is 66.5" NTN.It's had a good 1000 arrows through it already for sure now.I imagine it still shoots into the low to mid 170's for sure yet.
Not near all my self bows shoot like that though but some others do too.A slightly D/R KCT straight limbed self bow with 10" stiff levers 68" TTT shoots those numbers too with a 10 grain arrow.
Seems a fat FDC is essential for extra speed.

  I believe you, I have seen the same thing a number of times over the years. we call them outliers but they really are not, we just happened to get everything exactly right and don't always know exactly what we did right.

[Badger]

Yes. Apart from stiff handles I can't imagine what else it would apply to.

I can't honestly tell a difference between an angled or a curved static tip if the tips end up in the same relative position and the portion is the same length.

It may register on a measured force draw but  the feeling to the hand and arm would be hard to discern.

  Pat, one of the big differences between a heavily reflexed r/d bow and a recurve is that a recurve can still maintain more static limb. Too much reflex in a r/d bow and you get a squishy limb with too much working limb. Most of the losses in a bow are through vibration, the more working limb we have the more vibration losses we have.

[PatM]

I was referring more to the shape of the static tip. Say a 90 degree more or less angled tip versus one that is a half circle.

[BowEd]

Seems the more work a person can get out of a shorter working area while maintaining it's integrety there can go far for any type of bow really in efficiency.Getting the most out of it so to speak.With the outers reduced properly but stiff yet.Just one way to look at it I guess.A fine line to walk on that's for sure.It's a sorta complex question really why.There's many things to consider.The reason for the diverse answers on the subject.

[loon]

I think TBB basically said perry reflex, the mass thing principle and outer limbs as light as possible make more of a difference than recurve vs. straight?

[timmyd]

well I don't want to get in trouble here but I bujlt and sold glass bows for a while and did a lot of testing on all brands of bows. The best 'scientific' data out there for the masses are the tests Blacky did for the TBM. Everything tested the exact same, same specs, fingers and machines with fast flight strings and 9 gpp arrows. I'm an engineer so I really enjoyed reading these. I had a buddy who gave me his whole collection of TBM so I went through all of them and pulled out all the reports so I had a guideline on how my bows were performing. So that being said, the fastest bow he tested was a recurve  that shot 193 with a machine. The only longbow that came close was Adcock's hybrid longbow. I love a straight limb longbow as much as any design but don't let the love of the lore affect reality. Its the least efficient bow design. In all my testing, I have never seen a hill style glass longbow shoot over 170 drawn to 28" and 9 gpp. I've tested some myself and also other hill type designs and the vast majority fall into the 160 range some in the 150s and this is glass let alone self bows. There is no doubt in my mind that a good self bow craftsman could build a self bow that would compete with this but probably not most. From all my testing, a good rule of thumb that I noticed with bow designs was 160s for longbows, 170s for slight D/R longbows, 180s for hybrids and high 180s for recurves. Just my findings

[gfugal]

It's not just string angle. Considering long bows have good string angle. It's also about the length of the limbs. Greater length creates greater moment arms which increasr the inerta. The biomechanical equation for inertia is mk^2, where k is a variable of length and m is mass. As you can see length increases inertia much greater than mass does, since its variable is squared. The ability for the limbs to snap back in place as quickly as possible is expressed as angular velocity. Greater inertia causes angular velocity to drop. For example, in ice skating when they put their arms out they rotate more slowley than when they pull their arms in. In fact when they pull their arms in they spin much much faster. Notice the mass was not changed. The only thing different is how close that mass is to the axis of rotation. The sam principle applies to bows. Longer limbs are more stable and accurate. But for the same reason they can not rotate back to brace as quickly.

[sleek]

But they do so with less leverage

[bradsmith2010]

well I will just throw this in for fun,, last week I shot a straight tip sinew back bow I have been working on,,
55 1/2 nock to nock
55#@ 26 inches
180fps with 500 grain arrow,, about 9gpp
8 strand fast flight
big feathers on the arrow
most of the shots were in high 170's
I feel like a good release accounted for the 180 fps,,

I didnt have anyone spotting for me, I had tape on the arrow at 26 inches
I weighed the bow with a hand scale.proably not the most accurate,,
I am just saying these figures are a rough estiamate,, but a good indicator of what a straight tip bow can do,,

i have found in my experience, that a good release and fast flight string are a big part of improved arrow speed,,
I think I was building bows that shot really well, but never appreciated it with a heavy b 50 string and no so good release,,but alot of shooting though the chrono has improved my release and the lighteer string adds fps to that,

maybe this bow would have shot faster with a longer draw,, but since the sinew came off as posted earlier,, I wont ever know,,:)   

I hope to experiement with some recurves in the future,,and appreciate all the input,,

[BowEd]

Well to insure my figures were right us fellas go to a 3D shoot a few times a year here too.At that shoot a chronograph is set along the way to the targets.Costs a dollar a shot.I got exactly the same readings shooting through that chronograph as mine.Surprised the FG bows long ago with that but not anymore because they shot through there too with their FG bows and saw them not shooting any better on a lot of them.It was an educational experience to say the least.

[gfugal]

But they do so with less leverage

Hence recurves. Its the best of both worlds. You get the leverage and good string angle of a longer bow from the recurves/"levers" but also shorter limbs so they can rotate quicker when they snap back to brace.