** BROADHEADS ** Science & Math

[307]

What would the difference in ballistic coefficents between an arrow with a field point and an arrow with a "standard" broadhead?

Anyone know how to actually calculate this?

A broadhead tipped arrow would obviously supply more overall drag, and thus have a lower BC, by some amount.

Under that condition, one would have to think that some element of "lift" provided by the planing of the broadhead is the only way that a broadhead arrow can hit with a field tip at x distance.

They absolutely will not hit the same point at all distances, due to differences in BC, but it's quite feasible to get them to hit the same point at a single distance.

 

[justin davis]

Let's see a group of 10 field points at 100 yards. Or better yet, 12 ends of 5 for 60 arrows.

One of the reasons you're getting called out is you have a thing for posting these two arrow "hero groups" like you can do it all the time, when in actuality some of the best archers on the planet can't regularly shoot groups that small at that range.

Alright Ill shoot some 10 arrow groups for you if that helps prove my point that you can group fixed blades with field points.
Honestly I only practice with 2-4 arrows at a time. I shoot a couple arrows at a time. I practice just for hunting.

Yea never said I can shoot like that all the time. Some days I shoot lights out other days not so good. But I think that goes without saying.

Last week I was shooting at 120 yards. I took picture of two of the best groups I shot (sorry they were only 4 arrow groups). But crazy tight groups for 120 yards! These were with my old arrow setup that is a little weaker in spine.

 

[justin davis]

What would the difference in ballistic coefficents between an arrow with a field point and an arrow with a "standard" broadhead?

Anyone know how to actually calculate this?

A broadhead tipped arrow would obviously supply more overall drag, and thus have a lower BC, by some amount.

Under that condition, one would have to think that some element of "lift" provided by the planing of the broadhead is the only way that a broadhead arrow can hit with a field tip at x distance.

They absolutely will not hit the same point at all distances, due to differences in BC, but it's quite feasible to get them to hit the same point at a single distance.

I’m not sure that’s a good question. I can only shoot out to 120 yards before I run out of room with my sight and arrow. Yea I agree that broadheads won’t hit the same at all distances. At a certain point they will fall off. But I cant shoot far enough out to see where that is for my setup.


Awhile back I shot some rage and vortex expandables and some fixed blades (ramcat and iron wills). At 100 yards the expandables were hitting lower than the fixed blades and field points. But the expandables I was shooting have longer Ferrell than the fixed blades. So I think the longer Ferrel of the expandables created more drag and thus fell off and hit lower.

 

[Brendan]

Alright Ill shoot some 10 arrow groups for you if that helps prove my point that you can group fixed blades with field points.

Two things going on here.

1 - You shooting groups with more arrows isn't going to prove what people are saying here when it comes to field points and fixed blades, I'm not sure you're not "compensating" as well, or your bow is tuned for long range. You would need to Shoot your bow out of a shooting machine shooting your arrows with broadheads, and then with field points. At short, medium, and long range. Using same point of aim they will not group together at 100 yards if they are tuned to hit together at short to medium range. There are too many people who've tested this, including some of the best professional archers in the world, and physics is against you here.

2 - Nobody wants to see best groups all the time when they know it's not realistic, there's too much cherry picking / hero groups in threads like this. Post up realistic groups, which is why the cold bow challenge is probably the most realistic for hunting. But, go ahead and take 10-20 field point shots at 100, no broadheads needed, shoot at a fresh piece of paper, and then post that up.

 

[540-Virginian]

Alright Ill shoot some 10 arrow groups for you if that helps prove my point that you can group fixed blades with field points.
Honestly I only practice with 2-4 arrows at a time. I shoot a couple arrows at a time. I practice just for hunting.

Yea never said I can shoot like that all the time. Some days I shoot lights out other days not so good. But I think that goes without saying.

Last week I was shooting at 120 yards. I took picture of two of the best groups I shot (sorry they were only 4 arrow groups). But crazy tight groups for 120 yards! These were with my old arrow setup that is a little weaker in spine.

What broadheads you using?

 

[justin davis]

Today I was shooting with new arrow setup. These are stiffer than my other ones. I tore off some vanes off two arrows to refletch them to 4 fletch. Decided to shoot some bareshafts to see how they shot.

Shot a group at 30 yards

And then shot some at a sheep target at 106 yards. 2 bare shafts and 2 fletched. Snowing and cold. They shot pretty good. But seems like one of the bareshaft arrows is shooting high and left consistently

I’d be curious on seeing some bareshaft shooting from some of the guys that say you cant get fixed blades to shoot. In my experience if I can get my bare shafts to fly similar to fletched than fixed blades fly pretty well.

 

[roadrunner]

So, what does it mean when you have a 4 arrow, 2" group with field points at 30 yds and you cut fletching with arrow #5 tipped with a broadhead? What happens when you shoot one field point and the next is a broadhead and cut fletching?

All I can say is that the BH hits with the field point. I've done that, maybe on accident, but enough times that it wasn't a once in a million occurrence. Some will say BS, you can think what you want...

 

[540-Virginian]

Today I was shooting with new arrow setup. These are stiffer than my other ones. I tore off some vanes off two arrows to refletch them to 4 fletch. Decided to shoot some bareshafts to see how they shot.

Shot a group at 30 yards

And then shot some at a sheep target at 106 yards. 2 bare shafts and 2 fletched. Snowing and cold. They shot pretty good. But seems like one of the bareshaft arrows is shooting high and left consistently

I’d be curious on seeing some bareshaft shooting from some of the guys that say you cant get fixed blades to shoot. In my experience if I can get my bare shafts to fly similar to fletched than fixed blades fly pretty well.

You shoot bareshafts with broadheads?! How the heck is that safe lol? Seriously I’m curious if it’s possible or did I read your post wrong. Asking for a friend.

 

[Brendan]

So, what does it mean when you have a 4 arrow, 2" group with field points at 30 yds and you cut fletching with arrow #5 tipped with a broadhead? What happens when you shoot one field point and the next is a broadhead and cut fletching?

All I can say is that the BH hits with the field point. I've done that, maybe on accident, but enough times that it wasn't a once in a million occurrence. Some will say BS, you can think what you want...

That's easy and not what we're talking about. Very standard to get Bare Shaft, Broadhead, Field Point hitting the same at 30-40 yards, even 50-60 yards.

Now, Take those same arrows, same bow, same tune, and shoot them at 100 yards. Using the same point of aim, the broadhead will hit lower. That's what we're saying. Justin is arguing otherwise.

 

[justin davis]

You shoot bareshafts with broadheads?! How the heck is that safe lol? Seriously I’m curious if it’s possible or did I read your post wrong. Asking for a friend.

No no! I’m Not shooting bareshafts tipped with broadheads. I just shoot bareshafts with field points. I find that bareshafts mimic broadheads So I like to tune with bareshafts

 

[roadrunner]

You shoot bareshafts with broadheads?! How the heck is that safe lol? Seriously I’m curious if it’s possible or did I read your post wrong. Asking for a friend.

I remember back in the day when the max range for a broadhead was 35, maybe 40 yards. Some broadheads flew like a sidewinder missile with 4 fletches past 30. Of course, that was back when Satellite broadheads were "king" and the Punchcutter was the answer to everyone's broadhead problems being shot from their magnesium riser PSE Mach Flite 4 bows with a whopping 55% let off equipped with an overdraw to shoot a 24" 2216 Aluminum arrow...

 

[Billy Goat]

This needs to be changed to "popcorn" thread.

 

[roadrunner]

That's easy and not what we're talking about. Very standard to get Bare Shaft, Broadhead, Field Point hitting the same at 30-40 yards, even 50-60 yards.

Now, Take those same arrows, same bow, same tune, and shoot them at 100 yards. Using the same point of aim, the broadhead will hit lower. That's what we're saying. Justin is arguing otherwise.

The most deceleration will occur when the arrow is at the highest velocities, which is out to 40 yds. The further it gets, the less each decelerates. So, you're "hit lower" is really a function of the loss sooner than later.

We're talking about the science and math of broadheads. It's the exact same as it is for field points...

 

[Dos Perros]

Are people really dismissing the laws of physics here?

 

[Brendan]

The most deceleration will occur when the arrow is at the highest velocities, which is out to 40 yds. The further it gets, the less each decelerates. So, you're "hit lower" is really a function of the loss sooner than later.

We're talking about the science and math of broadheads. It's the exact same as it is for field points...

I don't disagree with that. But, physics shows you that more drag on the broadhead will slow the broadhead tipped arrow more, you get a lower average speed, more time to cover the same distance, broadhead tipped arrow drops more due to gravity.

Go back to the very first post on this thread and there's some data on it.

 

[RosinBag]

The most deceleration will occur when the arrow is at the highest velocities, which is out to 40 yds. The further it gets, the less each decelerates. So, you're "hit lower" is really a function of the loss sooner than later.

We're talking about the science and math of broadheads. It's the exact same as it is for field points...

I may be misreading this, but max velocity doesn’t occur at a certain distance, it occurs right out of the bow.

I can set my LabRadar up to measure the velocity of an arrow five times in the first 100 yards of arrow flight. Regardless of the intervals it will never increase speed after the initial reading.

I forgot who mentioned it, but the cherry picking of groups is the biggest issue most have with people and their groups. Justin always seems to post two arrows stacked on top of each other at some long range, seems as though he has never missed.

My standing challenge is still available for anyone who wants to come out to California and out their set up to the test. Shooting machine and their bow at 20, 60 and 100 yards. I am certain you can get them to hit together at one of those distances but not at all three. FP/BH at 100 together will have the broad head fairly high at 20 and vice versa if they hit together at 20, the broad head will be very low at 100.

 

[CamoPirate]

This thread should be on lockdown.

 

[RosinBag]

Or you could not read it. I personally think it is pretty good. There is plenty of good opinions and information in it for those that care to read it.

 

[Stalker69]

That's good stuff, thank you for that.

I've always been a multi-pin sight guy, but I've never seen a more compelling reason to switch to a slider, especially if anyone makes one where you can have two sight tapes at once.

You can use a blank tape and mark your shots with pencil or pen. Use black for field point and red or something for broad head.

 

[roadrunner]

I don't disagree with that. But, physics shows you that more drag on the broadhead will slow the broadhead tipped arrow more, you get a lower average speed, more time to cover the same distance, broadhead tipped arrow drops more due to gravity.

Go back to the very first post on this thread and there's some data on it.

Yes, the drag coefficients are the same, however, there is more surface area to act on with the broadhead. Total cross sectional area is greater, no doubt. The arrow whipping back and forth and rotating as it travels downrange will have the greater affect on the BH than FP because of what many call "wind-planing". The math and science is the same for both arrows. Both follow projectile motion equations and at the least, single variable calculus.(this is where all the equations come from, a mathematical representation described over limits of integration).

I may be misreading this, but max velocity doesn’t occur at a certain distance, it occurs right out of the bow.

I can set my LabRadar up to measure the velocity of an arrow five times in the first 100 yards of arrow flight. Regardless of the intervals it will never increase speed after the initial reading.

I forgot who mentioned it, but the cherry picking of groups is the biggest issue most have with people and their groups. Justin always seems to post two arrows stacked on top of each other at some long range, seems as though he has never missed.

My standing challenge is still available for anyone who wants to come out to California and out their set up to the test. Shooting machine and their bow at 20, 60 and 100 yards. I am certain you can get them to hit together at one of those distances but not at all three. FP/BH at 100 together will have the broad head fairly high at 20 and vice versa if they hit together at 20, the broad head will be very low at 100.

Maybe you are misreading this, maybe I wasn't clear. The faster an object is traveling, the more deceleration it will have up to a certain point and then reach a point where it isn't so much as it was initially. So, the most deceleration of any arrow is at time zero right as it leaves the bow system. Initially, drag is almost negligible, but as the arrow travels downrange at time 1 second, 3 seconds, and so forth, drag will begin to take its effect on the broadheads' increased surface area. Eventually, deceleration rate will be fairly close to each arrow, the effects are more pronounced on the broadhead earlier on.

Most of the arrow's velocity where higher deceleration affects it will occur within the first 20 to 40 yards which is why POI can be stated as nearly the same. Nearly the same can be measured by tenths of a inch up to somewhere between one and two inches. Again, no big deal at those distances and FP's and BH's hit the same as you can have that variation with any group with FP's - even with a shooting machine since no two arrows are the same and nobody hunts with just one arrow.

This small variation is compounded downrange at farther distances. The thread title is the about the science and math behind broadheads. My first post on this thread stated the science and math is the same for both arrows because it is, the outcome is variable. My second portion is the realism of most every hunting situation and shot distance that it clearly does not matter because both have the same POI.

The fact about the broadhead hitting lower than the field point at 100 yds is, in general, a moot point. Unless you plan to take animals at 100 yds which opens a whole new "let me get my popcorn" thread...

Are people really dismissing the laws of physics here?

Nope.