EFOC tunning

[Dozer]

Lets see if you guys can give me a hand with this problem. As stated in an earlier thread I just got some 2216 Legacy shaft cut too 29" After lots of bare shaft tunning to get the spine right I ended up with 350gr up front and a total arrow weight of 700gr.

I CANNOT get these things to fly right. I fletched three 5inch and 4 four inch. I've moved the nock point up and down slowly. I've tried to make sure I have a perfect release. This arrow did things in flight that just made me stare with my mouth open thinking how can a field tipped arrow do that. I can get them to spine right when bare shafting but cannot get them to stop porposing with or without the feathers. One time my feathers even did a huge pin wheel to the target. I got so ticked I snatched up all the new 2216 threw them in my shed and grabbed some woodies and shooting them just to make me feel better. If you guy haven't got any ideas that I haven't thought of I'm tossing the 2216 and sticking with my wood.  

[SOS]

What's your draw length?  Wonder if you cut them too short where your draw length/anchor is very critical.

[O.L. Adcock]

"As stated in an earlier thread I just got some 2216 Legacy shaft cut too 29" After lots of bare shaft tunning to get the spine right"

You say you got them to "spine right" and then can't get them to fly with fletching? Can't happen. What bare shaft method did you use?...O.L.

[Stringdancer]

So,  are you saying the only problem is the porpoising, or do they fishtail as well when fletched?  

If they fly straight without fletching they will fly even better with fletching.  The only thing I can think of would be a clearence problem.  Try building the shelf area up a bit directly over the deepest part of the grip, and see if that helps.

By the way, what are you shooting bow type, poundage, and YOUR draw length?

Mike

[Shawn Leonard]

Use OLs method of bareshafting, point of impact. To do it any other way is very hard as you would need a near perfect if not perfect release. Give us your set-up info as well and we may be able to help. Shawn

[Pat B.]

Shawn,when I get my bare shafts grouping with fletched shafts the flight of my bare shaft is near perfect.. However they normally show a slight tendendy to fly a tad nock high but I tune that into them on purpose. I'm pretty sure I don't have a perfect release but perhaps it's better than I think. Anyway the flight of my bare shafts in normally very very good...

[O.L. Adcock]

String Dancer said "The only thing I can think of would be a clearence problem."

Yep, those that try to use the kick or angle method usually wind up over spined and that causes clearance problems with the fletching.

Pat B. "when I get my bare shafts grouping with fletched shafts the flight of my bare shaft is near perfect.."

That's wonderful that happens but is not something to strive for. The best shooters shooting bare shafts into the gold at 70 or 90 meters, the shafts aren't going to be consistantly straight at any distance. If we could launch a shaft out of a machine perfectly straight consistantly over and over, they will not stay straight in flight due to what happens aerodynamicly. Add in our crummy releases and bow hand pressures and the angles in flight have nothing to do with how well the bow is "tuned"......O.L.

[Dozer]

My set up is a 55# Grizzly at 28" which is my draw lenght. It has the string that it came with. I don't know if its fast flight or not.
I do have my shelf built up on the highest point of the radius so the arrow only contacts one spot and not the whole rest.

When I bare shaft I shot a bare shaft at my Morrell target and juge what the spine is by how the nock flies. Nock left = weak spine. Nock right = stiff spine. Nock up = nock point to high. Nock low = nock point to low. This is the only way I know how to bare shaft. As of now I'm back too wood and my Legacy shaft has been relegated to a toy arrow with no points for my son. If I can make the Legacys work I'd like to as I do get tired of breaking the tips of my wooden arrows which is my only problem with them.

[O.L. Adcock]

Dozer, that's the "kick" method and it doesn't work very well for most folks and this is another example out of thousands. You are trying to fix form and aerodynamic quirks using spine and nock point, it won't work. Use the "planeing" method.   www.bowmaker.net/tuning.htm    .....O.L.

[JRY309]

For me I think EFOC works better with carbon arrows,but I like to keep aluminums or wood arrows around 10-14% FOC.

[Stringdancer]

Dozer,

Listen to (O.L. Adcock) he knows what he is talking about.

If it were me, I'd be trying a 2016 with a 125gr point.  I just don't understand the need for all the weight, and FOC.  Seems to cause more tuning problems than it's worth.  Everyone wants to shoot arrows 3X stiffer than needed, and add tons of weight up front, and I'm just not one who finds that necessary.  I'm not saying you can't get the arrow to fly good, I just think it complicates things.  

Mike

[O.L. Adcock]

EFOC does complicate things only because we have no baselines to start from and just too many variables. Few products to help us do it but that's changing. It's not necessary at all unless a person is trying to optimize accuracy, penetration, trajectory, or distance. Flirting with the edges of potential, then it adds up....

2216's are so far out of the ball park spine wise for a 55# Griz I don't know if it's even be possible to get as much weight up front that it would require. Even a 2117 would be pushing the upper limits....O.L.

[Dozer]

O.L. hearing you say that about my 2216's send my head spinning. I called and asked a reputable Traditional archery dealer whose name I won't mention because I'm sure I'll get deleted and they told me that if I wanted to shoot a heavy arrow head, 160 to 200 then I would need 2218's. I can't imagine what the weight of the arrow head would have to be to get that too shoot out of my bow. I think before I buy something new I'm going to ask the opinion of the senior members on this board instead of a salesmen.

Thank you gentlemen for you advice and O.L. Adcock for that link on bareshafting. I do like Stringdancer's comment and I think I will stick with what is working wonderfully for me already and thats a POC arrow with 145gr tip. It weighs in at 530grs which is close enough to 10gpi for me.

[O.L. Adcock]

Dozer, "I called and asked a reputable Traditional archery dealer whose name I won't mention because I'm sure I'll get deleted and they told me that if I wanted to shoot a heavy arrow head, 160 to 200 then I would need 2218's."

Lots of "Pro" shops lead folks astray also. I'm sure it's not intentional. Many will use the Easton charts and they are way out to lunch. Ordered a dozen glue-on 125gr BH's from one of those that advertise 200 years of combined "experience" and got 6-125's and 6 125's with screw-in adapters. Their first words were they were out of 125 glue-on's to just remove the adapters...Problem is those heads are 100 gr minus the adapters! 145's minus the adapters and would have been good to go!   ...O.L.