The case for a curvy longbow?

[Apex Predator]

The following is a comparison I did of my own personal hunting bows that I have built.  This is offered for discussion only.

These were both set up to hunt.  Both had normal, optimal brace heights, and string silencers.  The pronounced R/D had a 12 strand D97 string with cat whiskers.  The straight longbow had a 12 strand B-50 string with with wool yarn puffs.

I shot the same arrow with both bows.  The arrow weighed 577 grains.  I fired the bows by hand with a three finger under release.  Both were drawn to my full draw which was 49@28 for the R/D and 48@27 for the straight one.

I always draw a straight longbow to a shorter draw length due to the amount of heel in my grip, and the fact that most straight bow risers don’t measure  as deep, and the back of the riser is where I measure draw length.

Straight longbow averaged 142.4 fps with a 577 grain arrow (12.02 grains per pound)

 

Pronounced R/D longbow averaged  162.03 fps with a 577 g arrow (11.78 grains per pound)

 

I’m not much on KE numbers.  I will tell you that I have killed quite a few deer and hogs the last couple of years with the same straight longbow tested above.  The KE with that arrow combo is 26 ft/lbs.  The R/D I tested generates 34 ft/lbs with the same arrow.  I would feel comfortable shooting a mighty large critter with it!

These bows would shoot a lot faster if I were shooting skinny strings and lighter arrows.  The R/D will hit over 200 fps at 9 gpp and drawing 29”.  If shooting a skinny string, using a shooting machine and mech release, I think I could get 200 fps at 28” draw.

[Orion]

The differences you found are about what I would expect.  The pound or two more weight and D-97 string probably account for nearly half of the difference;  bow design the other half.  Good stuff.

[pdk25]

Numbers aside, those are a couple of sweet looking bows.  With the shelf on the wrong side, of course.  

[Rik]

Which bow are you more consistently accurate with when stump shooting?

[Apex Predator]

Orion,

I only gain 2 fps with that straight bow when shooting a D97 string on her.  I wanted this to be a comparison of these similar weight bows set up how I hunt with them.

I shoot the R/D better.  I've always been more consistent with the straight ones in the past.  This straight bow is 63" ntn, and a little twitchy compared to a 66" bow.  The only draw back to the R/D in increased noise.  There is no way around it.

[ny state land]

According to the Howard Hill site you can just add your draw weight to 115 and get the approximate FPS.I cant imagine they are going over 10gpi though. Looks to me that you are using more of a hunting weight arrow much like i would use. What length was the R/D in this test? Have you tried the B-50 on it?

[Dick in Seattle]

Drat you, Apex!   20 fps is a lot of difference. I'm sure glad my javie hadn't read that before I killed him with my straight bow!

I'd have expected 10 and ignored it, but you're trying to force me into finding or building an RD form and trying to make some RD bows, and you know that's against my religion!

Seriously, those are nice looking bows and that's a very informative comparison.

[Orion]

Apex:  Another difference between the bows is the string silencer material.  Cat whiskers are usually a lot heavier than wool puffs, depending on the amount of material used.  They can reduce your speed a few fps.  I'm not questioning your numbers, just trying to help explain them.  Most of the tests I've seen, when absolutely everything else is the same except the string -- B 50 or fast flite, the fast flite is usually 5-7 fps faster.  Other things,like placement of the string silencers, if they're different from one bow to the other, brace height, if they're not optimal for each bow and/or the same, etc.,  can account for some of the difference as well.  Your results, showing your heavy R/D bow about 13%, give or take a little, faster than the straight bow, is certainly consistent with what others have found.

[Apex Predator]

The R/D is 62" long.  All longbows should be comparable in speed if using a same grain per pound arrow.  I'm not sure how Craig tests his Hills for speed.

[Apex Predator]

My testing with my pronounced R/D has found a 3 fps difference between a 12 strand dacron and a 12 strand D-97 string.

[ron w]

I found this to be intresting, but I'm thinking the 66"er your going to build for me[Cumblerland] should cast a 500gr arrow with zip for deer size game and Black bear. Good info and something to think about........ron w

[Apex Predator]

I'll always have a straight one Ron.  They are killing machines, and a pure pleasure to carry in the field!

[ny state land]

Did you notice a difference in sound when using B-50 on the R/d. How about a longer one? I know I am getting of track  but I like longer bows and noticed  this is not a 66" R/D in your stable.

[Apex Predator]

On this particular model, the "Ossabaw", I find the D-97 to be quieter.  That's a first for me, as I have always preferred B-50 dacron on all my bows. I offer a mild R/D in a 66" length.  Currently the "Ossabaw", my pronounced R/D, is only offered in 60-64" lengths.

[ny state land]

OK, how would the mild R/D compare in the same set up. Just curios what kind of arrow was used?

[Apex Predator]

I don't have one to test besides these two, but from past testing, I'd expect it to fall right in the middle of these two.

I used a Gold Tip traditional shaft that was a little stiff for the straight bow.

[ron w]

Marty have you ever done testing with wood arrows and if so was there any differance worth mentioning? Just curious!

[OBXarcher]

good info Marty, I will have one of your bows in the near future I hope.

[Molson]

You have a straight limb bow that is shorter than it should be, using a slower string, and being drawn one inch less compared to an R/D bow that is at an optimal length, using a faster string, and being drawn one inch longer. I don't see how the numbers relate to each other as far as comparing their performance goes.  Given all the negatives added to the design of the straight bow, arrows that are too stiff, and increased string angle on the release, I think that 142 is great performance at 12 gpp.  I'm not saying you're not going to get better performance from an R/D over the straight bow, you will easily.  But I don't think the difference would be quite as dramatic if the slower straight bow wasn't made slower still with these handicaps.  Both bows look great!!

[dennis rice]

I have one of his 66" straight limb bows and im shooting a 600 grain arrow at 55 lbs. I have not shot any critters with it yet but it sure rocks my target.It's dead in my hand and shoot's where i look.