what do broadheads do to arrow flight /and or Spine?

[saumensch]

While tuning, i got desperate because not much seemed to work.
Just for fun, i tried some broadheads on the fletched shafts, and BANG, they were hitting exactly were i wanted whereelse the same arrow with a field point was not nearly as accurate.   :confused:  Whats going on there? Does a broadhead change the arrow flight or the dynamic soine? If so, how and in wich direction?

Regards

[Ragnarok Forge]

Yes it can if the arrow is not tuned properly.  You got lucky with the broadhead planing causing the arrows to hit where you want.  You need to go back to the start and find the proper spine, length of arrow and fletch, insert, tip weight that tunes properly for your bow.  Them tune your broadheads to your field points.  

You hit on a combination that works right now, change heads, head weight, etc... and you will be right back to where you started.  It helps to get a friend who is experienced to help you tune.  Post your arrow and bow specs in this post and lots of folks will help you out.  

Again, field points need to tune properly and broadheads need to tune with your field points.  Good tuning is critical to consistant arrow flight, which = better penetration.

[NDTerminator]

Broadheads put the weight further out in front of the end of the shaft than target points, and fixed blades are essentially wings out front trying to steer the arrow, same as the fletching does in back...

When you think about it, a fixed blade broadhead can't not affect arrow dynamics...

[Bill Carlsen]

I can't explain it, either but for the past 58 years I have noticed the same thing  as long as the bh weighs the same or very close to the field point and is on straight.

[Fletcher]

Are your field point and broadhead weights the same?  I paper tune with field points and do a final paper tune check with broadheads installed.  If the point weights match, there shouldn't be any noticeable difference.

Altho broadheads are generally longer, I find they are dynamically shorter.  The greater mass on a broadhead is toward the rear whereas on a field point, it is forward.  In reality tho, I feel the difference to be very small.

[Bill Sant]

If you have been building carbon arrows you know how much difference an inch or inch and a half of arrow length can have on the spine of any shaft.  That being said a broadhead that lengthens an arrow by that much will also change the spine.  If the broadhead is the same weight as you field tips, try getting another shaft and cut it longer, to match the broadhead length arrow.
Another way is to lighten the broadhead weight enough to stiffen the spine to compensate for the added length.
There are other factors that will come into play, wind planing, two blade, three blade, alignment, tip weight, fletching etc, but total arrow length seems to be the biggest problem solver I have played with.