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Post by Cossack on Sept 6, 2009 19:28:49 GMT -5
I shot the Vortex for a group tonight. Had a great 50 yard group going despite the wind when the 7th arrow went high and left. It had looked good upon release so I re shot at 30. Same arrow, high and left. Shot it alone, then I saw it's back rotate significantly. Checked the Blazers and found about 1/2' of the back of one vane was loose; the rest of the same vane was attached only on one edge (apparently I had re glued it that way when I noticed previously that it was coming off). I stripped it and re fletched that side with a new vane. Walla! Problem arrow behaving again. Lesson learned, vane orientation is much more important than I previously thought.
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Post by BT on Sept 6, 2009 19:59:38 GMT -5
I have seen this issue with blazers and attributed it to the mass of the vane.
That is to say that the vane needs to be perfect, or it really can be the undoing of the flight.
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Post by Cossack on Sept 6, 2009 20:13:48 GMT -5
Huh? Mass of the vanes, Blazers?! They are half the weight of the 4 and 5" vanes I was using! Why would Blazers be more susceptible to poor flight than any other vane not "perfectly" glued on?
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Post by BT on Sept 6, 2009 21:51:08 GMT -5
The mass I am referring to is surface mass.
The blazer has a high mass compared to a standard design in as much as it is higher.
The height is what allows it to be shorter and the mass that is gained by the height also allows it to impart greater drag ... hence the greater stability.
That heightened drag is also what makes it more susceptible to error when it is glued on incorrectly.
Other vanes would show less error because the issues would not be imparted over such a reduce area.
This is why the blazer is meant to be straight fletched rather than offset.
You can offset but you will not see better flight because of that offset.
At speeds exceeding 340fps, it is evident.
If it is evident at that speed it will be evident at slower speeds as well....just not as evident.
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Post by Cossack on Sept 7, 2009 7:15:48 GMT -5
You're providing some interesting food for thought BT. I'm still thinking that the 5" and perhaps even the 4" vanes that come on most stock CB arrows have a greater surface area (mass?). Are they not susceptible to the same malady?
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ghost
Senior Board Member
Posts: 813
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Post by ghost on Sept 7, 2009 13:39:53 GMT -5
This is why the blazer is meant to be straight fletched rather than offset. Interesting, most crossbow shooters that use blazers fletch them with a right offset or right helix. A few have tried straight but many go back to the right helix. The other vane many use is a 4,inch, fletch with one or two degrees of right offset. Ghost |
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Post by BT on Sept 7, 2009 18:24:06 GMT -5
The overall mass of the 5" is more but it is a less steep and therefore grabs less air.
Kinda like a VW beetle compared to a Ferrari.
Bohning first introduced these vanes with precautions pertaining to the orientation of the vane on the shaft.
I soon found out why when I put them on my standard jig which had a 2 degree offset.
Maybe the mass of the bolt has everything to do with better control over a long shaft?.
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Post by Cossack on Sept 8, 2009 8:33:43 GMT -5
Hmmmm. Mine are 4 degree offset, have used helical too (no advantage), but both work great...except for that one misattached blade.
I think the trick to stabilizing crossbow arrows, is a much higher FOC. I'm' using 18+% with my 290 and 315 fps bows (100 g heads) and over 20% for the 355 fps bow. The latter needs a 125 g head to meet minimum arrow weigh specs for the bow.
Basic arrow specs: Gold Tip Lazer II, 110 g brass insert and 2" Blazers.
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Post by awshucks on Sept 8, 2009 11:02:56 GMT -5
Those Blazers sure shoot good for me w/ an AZ-EZ in rt hand helical. I've also noticed less L-R drift shooting them in a crosswind compared to 4" Duravanes.
I tend to quit experimenting once I reach a level of satisfaction, lol.
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Post by horizontalhunter on Sept 8, 2009 19:06:59 GMT -5
Hmmmm. Mine are 4 degree offset, have used helical too (no advantage), but both work great...except for that one misattached blade. I think the trick to stabilizing crossbow arrows, is a much higher FOC. I'm' using 18+% with my 290 and 315 fps bows (100 g heads) and over 20% for the 355 fps bow. The latter needs a 125 g head to meet minimum arrow weigh specs for the bow. Basic arrow specs: Gold Tip Lazer II, 110 g brass insert and 2" Blazers. I shoot the same arrow with a 125g broadhead with excellent results. Bob |
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