Faster bow shoots lower?

[Red Dwarf]

Mostly I shoot a 48# R/D longbow; I do however occasionally shoot a 57# recurve.
For some reason, unknown to myself, the recurve shoots approximately 6" lower at 10 yds than the longbow even though it is a faster bow.
I use the same arrows for both bows and the knocking points are almost identical.
Any ideas on why the arrow impact point from the faster bow is so much lower?

Red Dwarf

[McDave]

Although the actual nocking points may be the same height above the shelf for both bows, the effect of those nocking points on arrow flight is not the same.  The tiller of the bow means the relative strength of the upper and lower limbs.  We set the nocking point based on the tiller of the bow and how we grip the bowstring.  You probably grip the bowstring the same, but the tiller of the two bows is probably different.  The best way to set the nocking point is to shoot a bare shaft, and move the nocking point up and down until you have level bare shaft flight, or slightly nock high bare shaft flight.  When the bare shaft flight is the same for both bows, then the nocking point is truly the same, even though it might be located in a different position relative to the shelf from one bow to the other.

Incidently, it is unlikely that you are optimizing your bows by shooting the same arrow out of them.  A 57# recurve will require a differently spined arrow than a 48# longbow.

[GreyGoose]

Don't know the length of your bows, but I would expect your grip, or maybe the way the string grips you - to be quite different if the recurve is significantly shorter than the longbow.  Not sure how that would affect arrow flight, though, and I'd probably follow McDave's procedure to sort it out.  Good luck!

Up/down torque on grip can and will sometimes make as much difference as you describe.

[Red Dwarf]

A little more info - My Longbow is a Caribow Wolverine 58" long, my recurve in an early 70s Bear take-down and is 64" long.
I shot the same arrow out of both bows as a constant.
I shoot with a very loose grip and do not think the torque on the grip is an issue.
The bear has 1/4" positive tiller and the Caribow has 1/8" positive tiller.
I shoot 3 under

Red Dwarf

I wasn't referring to you having an inconsistent grip.  They are of different design and therefore torque differently when braced. 1/8” tiller can also make a big difference in impact.

[sbschindler]

the higher poundage bow has a flatter tradjectory and at closer targets it will hit lower,, the lower poundage bow will have a higher trajectory and so it will hit higher,,,at 20+ yards the higher poundage bow will hit higher if you shoot it the same as the lower poundage bow,

[Stumpkiller]

Are you holding the longbow with a low grip/bent wrist and the recurve with a high grip/straight wrist?  That would do it.  The arrow is at a different angle off parallel with your forearm with a high grip vs. a low one.

Also, flatter shooting changes the arc of the arrow flight and it takes a while for your brain to settle on it.  Does me, anyhow.

[Red Dwarf]

Stumpkiller - I hold both bows pretty much the same, fairly high, with the only contact point being the cup between my thumb and index finger.
The grip on the Bear is a little "higher" in design however. The static balance point for both bows is right in the middle of the locator portion of the handle area.
The arrow shelf on the Bear sits 1/16" higher in relation to my bow hand. (Would tend to towards a higher trajectory?)

Howler - I can't see how a slower shooting bow can hit higher. If you clamped both bows in a vise with the arrows parallel to one-another the faster arrow would impact higher at all distances.

Red Dwarf

[McDave]

What you are saying is true: if two bows are held in a vise and shot at the same angle, the slower bow will impact lower than the faster bow at all distances.  However, that's not how we shoot a bow.  What Howler may be trying to say is that if you are used to shooting a slower bow, you can have low shot errors when shooting a faster bow, as illustrated in the diagram below:

 

The trajectory of the slower bow is illustrated by the upper curve, and the trajectory of the faster bow is illustrated by the lower curve.  Both bows are being shot at an angle such that they are on target at 30 yards.

The point being that the trajectory of the faster bow places the arrow below the trajectory of the slower bow out to the point of impact.  Beyond that, the trajectory of the slower bow falls below the trajectory of the faster bow.  So if a person were used to shooting a slower bow, it is possible that their arrows might impact lower than expected at closer ranges when shooting a faster bow.

[Red Dwarf]

McDave

Thanks for the interest. It appears to me that in your diagram the sight picture of the 2 shots would be vastly different.
Surely, if a gap shooter set up on the same aiming point then the faster arrow would have to have a higher impact point.
 (How to you get to include a diagram in your posts?)

Red Dwarf

[McDave]

Agreed that my logic applies more to an instinctive shooter than a gap shooter.

I just jotted out a diagram and scanned it to a .jpg file and then uploaded it to photobucket, from where I could import it into TradGang.  However, I made a mistake and so my diagram may not be there very long, because any picture you import into TradGang is supposed to be less than 600 wide.  I didn't check it, because I didn't think my simple diagram would be more than 600 wide, but it looks like it probably is wider than allowed, since it is stretching the page, which the mods don't like.