SEW, please read this and give me your input

[xcaliber]

This makes my brain hurt. Remember, accuracy killed the game, not speed! To accurately depict the real results you would need a wind tunnel, and a chronograph setup at the maximum distance the arrow was fired to post results beyond speculation. This is where the data talks, and the BS walks where I work. Remember, sales pitches are designed to sell, period! If video of recovery is available, and speed at end of flight VS. Target impact are available, you might have something, if not, speculation. Sort of like the predicted gas mileage my truck is supposed to get.

[SEW]

Currently, I have about 60% of the photos loaded onto Photobucket. It's now saying "wait" until trying again. I'm currently out of wind tunnels, didn't want to take the time(again, I did recently chrono speed decay out to 100 yards) to chrono the speeds all the way out because the subject at hand is trajectory. Shooting 2 identical arrows, except for offset and helical fletching, from 20-90 yards with a Xbow/arrows that groups <1 1/2" @ 100 yds, frequently <1" under ideal conditions, should give meaningful information. Would I present this as a doctoral dissertation in physics? Of course not. But shooting these arrows to 90 yards, side by side, will show if there are meaningful trajectory differences between helical and offset vanes: for a field point. What I'm challenging is the premise that helical creates a flatter trajectory for a crossbow arrow, which Gold Tip didn't actually state. They said "arrow". While it may apply to a vbow arrow, especially with a fixed broadhead, I strongly feel that there is not any such stabilization going on or needed with a crossbow arrow out of a decent Xbow.
Constructing experiments for fact finding such as the effect of the extra stabilization provided by helical vane orientation vs offset can be relatively simple. This one is adequate to me. Speed measurements and no wind situations might be interesting but would add little , IMO. The arrows are shot back to back so little difference existed.
So when Photobucket decides to behave, I'll post the pictures and add the narrative .

[xcaliber]

I'm certain your results will be data rich. Remember, some folks think a wet cat smells like a skunk. If you post variable, unsubstantiated data, you will be corrected. Don't use terms like maybe, or potentially, snugged, or tweaked. There must be scientific data to support scientific findings!
SEW, I love reading everything you post, and consider it well prepared, and accurate.

[steven in England]

It is spooky to me that this subject has come up at this time, I will try to explain why.
I have been shooting helical for a while now as they give much better broadhead control. However, last week I was reading about how much helical slows down an arrow due to the spinning using up the energy in the arrow. So I decided to look for info on the net, I could not find anything on this forum and all I could find on the net was,'Helical causes you the arrow speed to drop off a cliff after 30 yards.
In the end the best thing was for me to go out and do some testing, this is what I found.
Zombie with 110 grain brass inserts, 100 grain point and 3 degree offset blazer from the factory - initial velocity with M380 - 354fps - velocity at 60 yards 323fps - loss = 31fps.
Zombie with 110 grain brass, 100 grain point and roughly 1 degree offset with SK300 vanes - initial velocity 352fps - velocity at 60 yards- 322fps - loss = 30 fps.
Zombie with 110 grain brass insert, 100 grain point and 2 degrees of true helical - initial velocity 352/353fps - velocity at 60 yards 319fps - loss = 33/34fps.
So from my findings the helical only loses 3-4 fps more over 60 yards and as you would expect the impact height were all the same with the speed, FOC and weight being so close.

I then thought what happens if I put a fixed blade broadhead on the bolts. So I put a boltcutter on the helical shaft and the result was.
Initial velocity 336fps (this is because the bolt is now 50 grains heavier) - velocity at 60 yards - 302/303 - loss 33/34 fps.
No more loss than the field tip, however, the 50 extra grains would have helped the bolt not slow as quick.

One more observation was the 1 degree offset SK300 struggles with broadheads, the factory blazer shoots good with broadheads and the helical SK300 shoots the best.
I do have a EZ bolt fletch and someday I would like to compare blazers set with this fletcher against the 2 degree SK300.
I am sticking with helical vanes, no reason for me to change.

Steve,
If you get a chance it would be good if you could put an offset and helical through your chronograph at a distance to verify my findings.

Steven

[SEW]

I'm getting to hate Photobucket! I tried to send all to Boo by email to post but it read, "too large".
I'll somehow try to get it on some way. All I have is an iPad so that somewhat limits me as does my very limited computer skills.
Summary: the Gold Tip article doesn't apply to Xbow arrows.

Dry lab: a term for not really doing the lab work but coming up with a result from reaching around behind you and pulling it out and then backing in fictitious data to support your supposed result. For years this was done in bullet ballistics. The Accurate Rifle magazine editor did a test with a 8 twist and a 14 twist 22-250 shooting 40 NBT and recorded the MV of this apps ~4,000'/sec load. Difference? About 10'/sec. FWIW, the velocity difference between my 2 arrows was 1'/sec. Statistically insignificant. Since I can't post pictures yet, I'll let the cat out of the bag: 20, 60,80,90 yds, the vertical impact points were equal. At 40 yards, the offset was 1" higher. Likely was me.
Summary, helical and offset had the same vertical out to 90 yds. I may later chrono the speeds at 90 yds.

PS My M405 is set up for 445g arrows and has an Optimizer. I dialed in a lesser range for these ranges , i.e. 54 yds for 60 yds, and below 80 for the 90 yd tgt. and aimed at the lower hearts. Just wanted the arrow impacts about mid-tgt. Helical on rt and offset on left. As we can see, no discernible vertical differences out thru 90 yds.

[Boo]

[Boo]

[Boo]

[Boo]

[Boo]

[ThunderXB]

Great work both Steve and Steven!!!

[SEW]

FWIW, I did a velocity loss test of, I think, 445g helical Blazers , Spynal Tapp, 20", Grizz Tricked arrows a few weeks ago. M405.
1 yd - 369'/sec
20 - 360
40 - 354
60 - 337
80 - 325
100 - 311

This speed loss was likely a little more than if field tipped. Velocity loss 20-100 yds - 58'/sec, and only 25% energy loss ( 30' - lbs, 120 to 90).

[bowman81]

So, all this consternation over straight, offset or helical and the difference is..............3 fps and O" on point of impact out to 90 yards.

We really do argue over how many angels can dance on the head of a pin don't we?

Good work. If there is anything learned it is to look at all advertising claims with a critical, and jaundiced eye.

[Boo]

So, all this consternation over straight, offset or helical and the difference is..............3 fps and O" on point of impact out to 90 yards.

We really do argue over how many angels can dance on the head of a pin don't we?

Good work. If there is anything learned it is to look at all advertising claims with a critical, and jaundiced eye.

Broadheads will throw in another variable, especially in the accuracy department.

[aib1015]

Would a heavier or lighter arrow or a lighter poundage bow yield the same results?