** BROADHEADS ** Science & Math

[N2TRKYS]

So with the recent thread on fixed blade broadheads and field points impacting in the same spot through all ranges, I obviously respectfully disagree with that happening. @Billy Goat and I shared some PM's as he was interested in the actual numbers of speed degradation over distance. Today I went out and shout several arrows over the chronograph at 5', 60 yards and 100 yards. I am no scientist nor am I a mathematician, but here are my numbers.

Set Up: Hoyt Carbon Defiant 34, 69.5 #'s, 29.5" with a 420 grain arrow. The arrows are fletched with three, 310 Flex Fletch vanes if you want to take that into consideration for drag compared to your set up.

The field points were Easton Parabolic, the mechanical broadheads were Sevr and the fixed blades were G5 Montecs. (I also shot Slick Tricks and Ramcat Diamondbacks at 60 and they were very close to the Montec speed, so I didn't keep shooting them.)

The speeds are three shot averages at 60 yards and 100 yards. The speed at 5' were just one shot and recorded.

5'

Field Point - 282
Mechanical - 282
Fixed Blade - 282

* This was the outcome I expected.

60 Yards

Field Point - 256 (91% of initial speed)
Mechanical - 254 (90%)
Fixed Blade - 250 (87%)

* So the Mechanical was less than 1% slower (.0079) and the Fixed Blade was 2.34% slower than the Field Point.

100 Yards

Field Point - 230 (82%)
Mechanical -222 (79%)
Fixed Blade - 206 (73%)

So the Mechanical was 3.47% and the Fixed Blade was 10.43% slower than the Field Point.


This is why my opinion of that Field Points and Fixed Blades can't have the same point of impact over all distances. I believe that depending on your personal acceptable deviation from Field Points to Fixed Blades, one could think they were all impacting the same.

Side Note: I found the Montecs were only about 5" low compared to my Field Points, so I surmised my bow was set up to shoot the longer ranges closer. So I moved up to 25 yards and the Montecs were 4" high. So I reversed it and moved the sight to have the Montecs dead on at 25 yards, this put them roughly 16" low at 100 yards.

Obviously these were just my numbers with my set up and doesn't transfer across the board to every bow, draw weight, draw length, speed, etc. But all Fixed Blades will degrade speed at distance due to their drag factor compared to a field point regardless of the other factors present.

Just now getting around to checking this out. I've never had an issue with my broadheads hitting with my fieldtips and this proves it.

Good to the science and math behind it, cause some folks have to see results instead of taking people's experience for it.

 

[RosinBag]

I think the test showed the opposite. It appears you can make them hit at the shorter ranges and be low at distance, or good at distance and high up close.

 

[ontarget7]

I would also add that your conclusion with the broadhead of choice, the Montec is very similar to my actual results long range.

However the Slick Trick Standards, Ram Cats, G5 Strikers, Wasp Drone and Bullet I’ve had excellent results grouping right with fieldpoints out to 100 yards.

Montecs always fell off on the long range compared to the above.


Sent from my iPhone using Tapatalk

 

[RosinBag]

Shane, which Ramcat? I shot the first version and the Diamondback. The Diamondback was substantially better at distance than the original version.

 

[ontarget7]

Diamondback

I really don’t think their scoop foils or whatever they call them is marketing hype etc.
They seem to do well long range.


Sent from my iPhone using Tapatalk

 

[rodney482]

I tried to explain this to the experts on AT long ago. At 60 yds and beyond poi is not going to be the same.

** I stopped shooting FP out of my hunting bow long ago. I also love VPA heads because I can practice w each hunting arrow and then resharpen.

 

[N2TRKYS]

I think the test showed the opposite. It appears you can make them hit at the shorter ranges and be low at distance, or good at distance and high up close.

I don't shoot animals past 40 yds. My broadheads hit with my fieldtips throughout that range.

 

[justin davis]

Lots of variables no doubt.

However, the right tune, the right amount of helical and fletching combo, with the right broadheads and it’s definitely possible to get them grouping together out to 100 yards with fieldpoints.

Can’t even remember the last time I’ve broadhead tuned any of my bows. Perfect bareshaft flight with entry matching fletched and I’m golden with broadheads.


Sent from my iPhone using Tapatalk

Yea this has been my experience as well.

 

[5MilesBack]

I don't shoot animals past 40 yds. My broadheads hit with my fieldtips throughout that range.

Out to 40 is pretty easy with most any setup. Fletching types really doesn't even show up much out to 40. BH type doesn't even show much difference to 40. It's beyond 40 that all the differences start to show up, and everything has to come together well for precise shooting.......regardless whether you're shooting at animals or targets.

 

[N2TRKYS]

Something I noticed a few years ago, was the difference between 4" and 2" vanes. I didn't do any type of testing, but noticed that my 2" vanes were driving deeper into my targets than my 4" vanes. This was even at closer ranges.

Now, that was years ago when I made the switch to 2" vanes.

Out to 40 is pretty easy with most any setup. Fletching types really doesn't even show up much out to 40. BH type doesn't even show much difference to 40. It's beyond 40 that all the differences start to show up, and everything has to come together well for precise shooting.......regardless whether you're shooting at animals or targets.

I'm only concerned with the BHs to the distance that I shoot animals. What do I care what it does at 100 yds?

I have noticed differences between 4" and 2" vanes inside that distance. Not poi, but the penetration.

 

[5MilesBack]

I'm only concerned with the BHs to the distance that I shoot animals. What do I care what it does at 100 yds?

Like I said earlier.........some people are only interested in "hitting" the pie plate, and others aren't happy unless they're hitting the exact spot they're aiming at on the pie plate. Similarly, some people aren't interested in shooting long range, and many others are. This thread is for the latter.

As for 2" vs 4" vanes........several years ago I tested my 2" QS Speed Hunters versus the 4" QS's at 80 yards. The arrows with the 4" vanes hit consistently 18" lower at 80 yards........even when using 100gr points versus 125gr points on the 2" vaned arrows. That's huge. But at 40 yards, they were all in the same 3" bullseye......not that much difference.

 

[MtnOyster]

So with the recent thread on fixed blade broadheads and field points impacting in the same spot through all ranges, I obviously respectfully disagree with that happening. @Billy Goat and I shared some PM's as he was interested in the actual numbers of speed degradation over distance. Today I went out and shout several arrows over the chronograph at 5', 60 yards and 100 yards. I am no scientist nor am I a mathematician, but here are my numbers.

Set Up: Hoyt Carbon Defiant 34, 69.5 #'s, 29.5" with a 420 grain arrow. The arrows are fletched with three, 310 Flex Fletch vanes if you want to take that into consideration for drag compared to your set up.

The field points were Easton Parabolic, the mechanical broadheads were Sevr and the fixed blades were G5 Montecs. (I also shot Slick Tricks and Ramcat Diamondbacks at 60 and they were very close to the Montec speed, so I didn't keep shooting them.)

The speeds are three shot averages at 60 yards and 100 yards. The speed at 5' were just one shot and recorded.

5'

Field Point - 282
Mechanical - 282
Fixed Blade - 282

* This was the outcome I expected.

60 Yards

Field Point - 256 (91% of initial speed)
Mechanical - 254 (90%)
Fixed Blade - 250 (87%)

* So the Mechanical was less than 1% slower (.0079) and the Fixed Blade was 2.34% slower than the Field Point.

100 Yards

Field Point - 230 (82%)
Mechanical -222 (79%)
Fixed Blade - 206 (73%)

So the Mechanical was 3.47% and the Fixed Blade was 10.43% slower than the Field Point.


This is why my opinion of that Field Points and Fixed Blades can't have the same point of impact over all distances. I believe that depending on your personal acceptable deviation from Field Points to Fixed Blades, one could think they were all impacting the same.

Side Note: I found the Montecs were only about 5" low compared to my Field Points, so I surmised my bow was set up to shoot the longer ranges closer. So I moved up to 25 yards and the Montecs were 4" high. So I reversed it and moved the sight to have the Montecs dead on at 25 yards, this put them roughly 16" low at 100 yards.

Obviously these were just my numbers with my set up and doesn't transfer across the board to every bow, draw weight, draw length, speed, etc. But all Fixed Blades will degrade speed at distance due to their drag factor compared to a field point regardless of the other factors present.

I did this same comparison 3-4 years ago and I pretty much came to the same numbers (basically) my conclusion wind drag on fixed blades starts to make a difference (slightly) at 20 yds and the difference keeps getting worse.
I think your numbers are spot on.

 

[N2TRKYS]

Like I said earlier.........some people are only interested in "hitting" the pie plate, and others aren't happy unless they're hitting the exact spot they're aiming at on the pie plate. Similarly, some people aren't interested in shooting long range, and many others are. This thread is for the latter.

As for 2" vs 4" vanes........several years ago I tested my 2" QS Speed Hunters versus the 4" QS's at 80 yards. The arrows with the 4" vanes hit consistently 18" lower at 80 yards........even when using 100gr points versus 125gr points on the 2" vaned arrows. That's huge. But at 40 yards, they were all in the same 3" bullseye......not that much difference.

I only practice at double my hunting distance. However, I never saw the need to shoot my BHs outside my hunting ranges. I get the benefit of the practice without having to setup my bow for something I wouldn't use for hunting.

Good luck this season.

 

[ontarget7]

Sent from my iPhone using Tapatalk

 

[Topo_trekker]

4 fletch for the win! I think all the “science and math” showed was dude is under-vaned. Lol.


Sent from my iPhone using Tapatalk

 

[nexus]

Okay, so I looked at the OP's chrono data and all the "real world experience" posts; I am wondering why both sides of the argument can't be right here.

Clearly the data shows a dramatic drop in arrow velocity at greater distance with the introduction of the broadheads. But it would seem to me that this reduction in velocity is less a function of broadhead drag (force/resistance to the broadhead shape) versus the likely increased vane steering necessary to offsetting the initial planing (cross force) of the broadhead at launch. I would think, the induced drag on the vanes is the greatest drag coefficient; that's why we use different styles, lengths, and heights to steer an arrow.

That being said, the impacts of broadhead planing should be able to be minimized through fine tuning to significantly reduce the larger vane steering impacts. There are many different forms of tuning, but it would reason that if one is trying to ensure that the bow is casting the arrow in direct line with the force from the string to minimize initial future broadhead planing, bare shaft tuning (zero vane steering) would be well suited for the job (also checks arrow spine - minimizing vane steering associated with shaft flex). I would suspect that is why Shane (ontarget7) can demonstrate that his fixed blade broadhead hits with his field points at 80 yards. He has tuned his bow to the point that the dominant vane steering forces have been minimized regardless of point. And as the OP chrono data showed, if the bow was not finely tuned (Shane feel free to take your bow out of tune prior to hunting season to demonstrate...lol) the vane steering forces would greatly increase and result in field points and broadheads having significantly different POIs and velocities down range.

Lastly, if the difference in POI was predominately related to the drag coefficient of the broadhead design, this would be a constant and not able to be compensated for at all distances as previously posted (i.e., on target at 80 yds but high at 20 yds). However, if the real issue is vane steerage, then once tuned, the bow should shoot spot on at all distances out to the limits of your tune.

Shane we've seen the video at 80 yds and that your bow appears tuned for this distance, can you shoot the same arrows at 20, 40, and 60 to see how "high" your arrows impact relative to each other at these distances?


I need more coffee this morning....

 

[RosinBag]

Your pose is very well worded and makes sense when read. Surgery that my theory is that the initial launch of the BH launches slightly higher because of how it planes and that is why you can make them hit at 80, but makes them high at 20. Or vice versa if you want them in the shorter yardages.

As far as fletching, I think total surface area of the bane steers more with more. So three 5” vanes would steer and have more drag than four 2” vanes. Or so I think, but I am not an engineer.

I think Shane is an outstanding guy when it comes to tuning. In his video he even states he wasn’t able to hold in the exact same spot. I also think two arrows isn’t enough for me to say it is doing what the video is trying to show.

I say put a fresh target up and shoot 20 of each and see if they are still doing what the video portrays.

And in reality, the human is still involved. Putting it in a machine will tell the story.

I have had a standing bet for a couple years now. I will modify it to that if someone just wants to ship me their bow, arrow and BH set up, I will shoot them through the machine and let them know exactly how well their bow is doing as it relates to BH’s and FP’s having the same POI. If they are right I will pay for shipping both ways and send them a $100 gift card to the store of their choice. If your bow is wrong, you just pay for shipping both ways.

Many many people keep saying their bows do this or that, and I honestly think they believe that because either their personal dispersion or acceptable groups are not that great, they don’t shoot enough arrows to know if it’s grouping because they only shoot one or two arrows at a time.

No one wants to know their set up isn’t as good as their mind says it is.

And reality is, the average archer makes a well executed shot about 50% of the time, and that may be a high estimate. So to think all these people out there that don’t shoot groups for accuracy, dispersion tolerance, to identify a poor arrow, etc are the ones preaching how perfect their BH’s and FP’s are, I just don’t buy it.

Many people have never even shot under pressure of a tournament, for money or at a trophy animal to even understand how their set up is going to perform.

 

[kupper]

The vane configuration isnt going to stop the broadhead from having more drag than field points. I've tested blazers, promax, max hunters, max stealth, and fusion q2i's all in a 4 fletch and all of them with a broadhead drops low of my field points at 100 yards. This is really no different than testing the same arrow configurations with a different amount of fletchings at distance. The more surface area you add in vanes the lower the arrow drops compared to the same arrow with less vanes.

 

[Trial153]

Totall anecdotal observation on my part. A while back I went over a hump where I felt like I was no longer happy with my sight tapes with at longer distance switching from Fp to Broadheads I began building my tapes based on broadheads POI only at long distances ( 60 out ). At closer ranges it a was non issue.

 

[nphunter]

RB, great info, I have always felt that after getting my bow tuned perfectly with bare shafts out to 20 that I was having to detune it to get my broadhead and field tips to hit together at 70. It is easy to do IMO but you are right, after getting them to hit together at 70+ I loose my perfect bare shaft flight at 20. Honestly, I don't think it's enough to make a difference and I do get them moved together at the further range because the close ranges are still well within the kill zone.

Aerodynamics come into play and every projectile is shaped different and at some distance, you will notice a difference. Speed also makes a big difference, fast arrows create more drag and slow down quicker than slow arrows with the same setup. I shot 315fps for a while with fixed heads and there are very few broadheads I could get to group well at 70+ yards at those speeds, i can get most to do well under 280fps.