Arrow Rest Timing

[Brendan]

Setting up and tuning a bow right now after installing new strings, and am considering changing how I time my arrow rest - i.e. how long it supports the arrow before dropping.

I'm using a Hamskea limb driven. In the past, I've had the arrow rest come all the way up just before I get to full draw such that the limb cord is barely slack at full draw. And vice versa - it starts to drop right as the cam starts to roll over after I release. But, listening to a podcast (Dudley) got me thinking about changing it, and it's something I haven't thought about before.

His comment was that having the arrow be supported for 6-8" or so until it starts to drop will actually make paper tears (and corrections) show up easier when you move the arrow rest. Thinking about it more, this should make it easier to get a perfect tune as small adjustments of the rest make a bigger difference the longer it supports the arrow.

Any comments? Am I thinking about this right? Has anyone played around with this to see how it made tuning easier / harder?

 

[Sharp Things]

I set up a fair number of bows as well as experimenting with a variety of rests and their timing. Its part of the process Im undertaking in designing a new drop away rest for a client. I find it very helpful to set up a smart phone (set on slow motion) on a tripod and film the rest activation. What some dont account for is arrow flex during launch and how arrow flex can make an arrow appear to be dropping when its actually flexing. Another is nock travel (its not always a straight line as you might think)

After filming I use windows live movie maker to further slow the footage.

here is a video of a rip cord rest to give you example of what can be learned with the video.

[video=youtube;KpsBvvCZHLY]https://www.youtube.com/watch?v=KpsBvvCZHLY&index=28&list=UUrDKSMxGGaa59V0uZPABJ6Q[/video]

 

[Sharp Things]

Another.

[video=youtube;QDCsIhNAT2E]https://www.youtube.com/watch?v=QDCsIhNAT2E&list=UUrDKSMxGGaa59V0uZPABJ6Q&index=27[/video]

 

[Brendan]

Don't mean any offense by this - but that really didn't have anything to do with what I was asking. I know all about arrow flex and clearance. I'm asking about rest timing, how long the arrow is supported, and impact on tuning / tears / bare shaft flight.

 

[Sharp Things]

Its the arrow support time Im talking about. Im addressing the exact question you are asking. That "up" timing to lift the arrow is the same as down "drop" timing. The point being, you have the ability to see for yourself what each inch of change of drop or lift means to you in regards to fletching clearance (the reason for drop aways) and allows you to optimize based on your bow and arrows and fletching.

Then I set up a camera to capture arrow flight for the first 10 yards to see the flexing off the rest.

[video=youtube;aSV0oG5FcXE]https://www.youtube.com/watch?v=aSV0oG5FcXE&list=UUrDKSMxGGaa59V0uZPABJ6Q&index=16[/video]

All this said, Its my opinion that paper tune is not useless but its only a starting point in the tuning package. Bare shaft, French, Broadhead, etc all play a role in arriving at great broadhead flight. I pay the least attention to paper tuning. Ive set up bows that paper tune with field points perfectly but cant shoot a broadhead worth a damn.

Rest timing and how long the arrow remains supported plays a role as an arrow flexes opposite the supported side so in the case of the lower launcher, the arrow flexes up and down. That spine/flex and nock travel (we would like to think its a straight line but its not always) will change how your arrow comes off the rest based on the number of inches your arrow is supported. You can easily experiment in one inch increments to see the effects. This is an aid that allows the user to set the number of inches of support before drop to optimize tuning as well as fletching clearance.

Spray an arrow shaft white and use a sharpie to mark off 1 inch increments on the arrow and then film the release and watch the drop. You will find great value in that. Then use acetone to remove the paint. Hope this helps.

 

[Brendan]

Sharp Things - please stop posting to this thread for the time being. PM coming.

Back to the topic at hand - would love to hear experience about when the launcher blade begins to drop after release, how long the arrow is supported, and the impact on arrow flight and ease of tuning.

 

[icb12]

I tried playing around with the timing when I was running a limbdriver. It was kind of a pain to set up to hold longer and still avoid contact, and once I managed that- nothing groundbreaking happened. I personally couldn't tell a difference in tuning or my shooting.
Somebody who is a better shot or has perfect form should be able to see a difference. But I couldn't.

FWIW- the longer the rest was holding my arrow- the more level my nock point got. (Makes sense)

 

[OR Archer]

I do this occasionally. Now how I do it is by changing where I tie the cord at along the limb. This doesn’t work on all bows however. By moving the tie in position I can influence high/low tears through paper without changing my nock or rest position while still maintaining clearance.
For high tears tie closer to the limb pocket. Low tears closer to the limb tip.

Hopefully this answered your question as I understood it.

 

[Brendan]

I can see where you tie having an impact on high / low tears (haven't played around with it for that reason) because you're supporting the arrow for a different amount of time while the nock is still on the string, and I'm sure vertical nock travel plays into that too. But, I don't think that's what he was referring to.

Dudley's comment was more of a starting point - the question was how long do you like to have the rest support the arrow after you release? His response was that he didn't like the rest to drop right away, because if you left the rest up for a longer period of time it made your arrow flight (and thus paper tears) more responsive to rest changes as you moved through the tuning process .

Not sure he worded it completely correctly, because the only thing I can think of is this: Let's say your rest is set 1/8" outside or inside of ideal center shot. The longer the rest supports the front of the arrow after release, the angle of the arrow from center shot will continue to increase as the string moves through the power stroke until the rest drops and is no longer supporting the front (Think trigonometry between nock, rest, and center shot). That way - it *should* magnify the impact of having your rest out of alignment...

So anyways - I'm not chasing an issue myself, but was stuck in the car for 5-6 hours over the weekend listening to podcasts, and this came up as a discussion I hadn't considered, and I'm trying to get the bow tuned this week. I've always wanted it to drop as quickly as possible, with the theory being shortening contact between arrow and rest further minimizes any torque I can deliver to the arrow during the shot...

 

[OR Archer]

Now along those line though what you may see with rests like a Trophy Taker with a steep V on the launcher is a false high tear along with a left/right tear. With more guidance a left/right tear can ride up the launcher causing a high tear also. So correcting for the left/right first can help the high portion.
Not sure if that’s the kind of information he was trying to convey.

 

[Sharp Things]

If you time the so that it up as soon as possible and just barely drops as the fletching arrives and then only change the cord length and nothing else so that is supports the arrow the least amount of time, you will have your answer and can report it back here (since you are setting up and tuning any way and its so easy to change)

 

[Beendare]

Dudley knows his stuff...that said, so do the Hamskea guys....I would give them a call.

I setup my QAD per their spec and my compound shoots BH's/FP's to the same POI at 60 yds. Heck, that bow will shoot much better than I can shoot it.

 

[Tony Trietch]

I have the cord tied onto the limb so that the arrow is supported up until the last second. I will play with where it is tied on the limb while the bow is on the draw board to see exactly how long.

 

[Sigfla]

Can’t you also adjust the cord location on the arm (like the versa rest) to affect this? Sooner the launcher drops the farther out on the arm the cord is versus later the closer you are to the 8 sided shaft?

 

[mfllood3800]

I have the cord tied onto the limb so that the arrow is supported up until the last second. I will play with where it is tied on the limb while the bow is on the draw board to see exactly how long.

Yep. I just set my Hamskea up today. I got the versa instead of the hyb hunter.
I played with where it mounted on the limb as well as tension on the cord, to get the arrow to stay supported until about the last 8" of the shaft. How ever the rest is dropping long before this, some where around half the shaft length I believe, At least that's what the draw board was revealing. I am not sure how similar this will be in real time.

This is my first limb driven. I have shot QAD exclusively for years, before that just a biscuit, so I am learning. I haven't seen/heard Dudleys video/pod cast on his rest. I am assuming its his rest? Probably the same principle regardless.

I finally got a bullet hole, and will hit the range tomorrow.

 

[Brendan]

For me - it's not about how to make the adjustment. It's why to adjust it one way vs. the other... Easiest way to adjust this for me is just move the cord in/out the limb with the bow in my draw board.

Went back and looked at some of Dudley's articles. He wrote a lot on the choices between blades and drop-aways, and then setting up both. In the articles he said he went for having the rest come fully up 4-5" before full draw, but then would tune from there. Problem is - no info on the why, or what tuning, etc.

I may just set mine up to support the arrow as long as possible and see if it makes a difference, but my guess is it'd be a very subtle change... The Hamskea is a little bit a cross between a blade and a drop-away anyways with the adjustable tension on the launcher and adjustable blade angle.

 

[mfllood3800]

Would I be wrong in assuming that the longer the arrow stays on the rest the more "correcting" or hiding it can do to the improper tune?
And the earlier it is off the rest and relying on the bow set up, the more it would reveal the bow tune errors. ?

 

[Brendan]

Would I be wrong in assuming that the longer the arrow stays on the rest the more "correcting" or hiding it can do to the improper tune?
And the earlier it is off the rest and relying on the bow set up, the more it would reveal the bow tune errors. ?

That's one theory that I've heard. The other is the longer the arrow is in contact with the rest, the more chance you have to torque the bow and negatively affect arrow flight...

 

[mfllood3800]

That's one theory that I've heard. The other is the longer the arrow is in contact with the rest, the more chance you have to torque the bow and negatively affect arrow flight...

That makes sense but then that isn't bow tuning effected, by arrow on rest duration, rather it is poor form creating the issue. A guy could have perfect bow tune, and then untune it to cover poor form. One reason I never let someone else set up my bow. I try to have perfect form, but in the end, its how that bow shoots in my hand.

But for the theory you ask, Id say getting it off the string early exposes the "Bow" set up best.

 

[Brendan]

That makes sense but then that isn't bow tuning effected, by arrow on rest duration, rather it is poor form creating the issue. A guy could have perfect bow tune, and then untune it to cover poor form. One reason I never let someone else set up my bow. I try to have perfect form, but in the end, its how that bow shoots in my hand.

But for the theory you ask, Id say getting it off the string early exposes the "Bow" set up best.

My view of it is this: you want to tune the bow for the most forgiveness (Similar to torque tuning). If one of two setups allows me to get a more perfect tune easier, and/or makes the bow more forgiving of form errors, that's what I'm looking for.