# Function of Plunger Button



## vsaluki (Feb 28, 2011)

I was watching some slow motion clips of arrows leaving the bow, and I must say that, visually at least, it doesn't look like the plunger button is doing much of anything.

http://www.youtube.com/watch?v=2fyBN99lh-4&feature=related

http://www.youtube.com/watch?v=iIMpLv6U67w&feature=related

http://www.youtube.com/watch?v=8sbZWgGsdUI&feature=related


And would you call that a high grip that Park uses?


----------



## Joe T (Apr 5, 2003)

The plunger button's sole function is to do with tuning and tuning effects can practically only be seen by where the arrows hit the target. So as you say the plunger button visually will not be seen to have any effect on the arrow during the shot.

It's similar to aiming. A fractional change in bow position won't be visible on a video but can have a significant effect on where the arrow hits.


----------



## vsaluki (Feb 28, 2011)

My thought is that I would have seen at least a little compression of the plunger at the beginning of the shot when the flex is suppose to be to the inside. But I saw none. And there was no plunger contact at all after about the first 6-8" of arrow movement. I'm wondering if the pros induce less lateral string movement, and therefore less initial bending to the inside, by the way that they just relax their fingers for the release.


----------



## coldshock (Feb 27, 2011)

Just to side track a bit, I was wondering if anyone could tell me what the difference is in plunger lengths and their applications? I was thinking about purchasing one and they seem to come in short, standard, or long. What determines what length should be used?


----------



## ArtV (Jan 29, 2008)

Push the arrow around. Center shot bows are not center shot..they are left or right shot, meaning the button brings the arrow into center


----------



## Viper1 (Aug 21, 2003)

cold -

Risers have different sight window geometries and some of the deeper ones require a longer barreled plunger to place the arrow in the correct position. I try to leave my plungers in the riser whenever possible, so if I can get away with a short barreled one, I'll go for that. 

Viper1 out.


----------



## coldshock (Feb 27, 2011)

Viper1 said:


> cold -
> 
> Risers have different sight window geometries and some of the deeper ones require a longer barreled plunger to place the arrow in the correct position. I try to leave my plungers in the riser whenever possible, so if I can get away with a short barreled one, I'll go for that.
> 
> Viper1 out.


Thanks Viper1. I plan on getting a cavalier master for my hoyt horizon. I think the standard size will work just fine for my noob set-up and even better if I can keep it in the riser.


----------



## vsaluki (Feb 28, 2011)

"Thanks Viper1. I plan on getting a cavalier master for my hoyt horizon."

I've got a standard length cavalier master plunger button on my Formula Excel. I've used mine to line things up so that a centershot line through my string and riser goes by the right side of the tip of my arrow when it is undrawn. That is the image that the Hoyt manual tells you to line up to. Another source I have seen seems to indicate that the right side of the tip should be one arrow width to the right of the centerline. I'm going by Hoyt's manual for now. But in any case, my medium plunger seems to have more than enough space for either type of lineup. And I suspect that if it's okay for my Formula Excel that it will also be okay for your Horizon.


----------



## need-a-bow (Aug 10, 2010)

Hows the horizon working out for you? Im planning on buying one soon.


----------



## vsaluki (Feb 28, 2011)

As an interesting aside about tuning, I noticed that in clips 1 and 2 above the fletching is well clear of the rest and plunger button as it goes by. In clip 3, the fletching seems to hit the rest.


----------



## coldshock (Feb 27, 2011)

need-a-bow said:


> Hows the horizon working out for you? Im planning on buying one soon.


So far I am really enjoying it but I don't have much experience to base anything. It is my first riser and my setup is basic right now. It shoots pretty smooth even with my inexpensive limbs. I just got my 30" stabilizer but have not used it yet. I have mostly been slinging arrows for fun. I am in the process of searching for an instructor in the area to get me going on the right foot.


----------



## Warbow (Apr 18, 2006)

vsaluki said:


> I was watching some slow motion clips of arrows leaving the bow, and I must say that, visually at least, it doesn't look like the plunger button is doing much of anything.
> 
> http://www.youtube.com/watch?v=2fyBN99lh-4&feature=related


I disagree. If you look at the first video the plunger is notably pushed in just after the arrow is loosed. It may be pushed in as much as 1/8 of an inch, and then "slowly" recovers. I don't have video analysis software on my mac, but if you have some with measuring capability for comparason I think you'll find that the plunger is indeed moving.


----------



## vsaluki (Feb 28, 2011)

Warbow: "If you look at the first video the plunger is notably pushed in just after the arrow is loosed."

You have better eyes than I do Warbow.


----------



## Warbow (Apr 18, 2006)

vsaluki said:


> Warbow: "If you look at the first video the plunger is notably pushed in just after the arrow is loosed."
> 
> You have better eyes than I do Warbow.


You could be right. It looked like it was moving but it could also be a trick of the lighting.


----------



## Viper1 (Aug 21, 2003)

Gents -

If you want to find out if the plunger moves or not (assuming you have it set somewhere near mid-tension), shoot a group and bear shaft tune at a given distance and then lock the plunger (make it as stiff as possible or replace the spring with a matchstick). See if either the group shifts or if bare shafts behave differently.

Pictures may not only be deceiving, but you also have to understand what you're seeing 

Viper1 out.


----------



## Warbow (Apr 18, 2006)

Viper1 said:


> Gents -
> 
> If you want to find out if the plunger moves or not (assuming you have it set somewhere near mid-tension), shoot a group and bear shaft tune at a given distance and then lock the plunger (make it as stiff as possible or replace the spring with a matchstick). See if either the group shifts or if bare shafts behave differently.
> 
> ...


I don't question that plungers work. I know that they do from matchstick tuning. In this thread I'm more interested if the deflection is visible in video.


----------



## vsaluki (Feb 28, 2011)

Warbow: "It looked like it was moving but it could also be a trick of the lighting."

Nice job with those frames. Yeh, I can't be certain either. What is easy to see, however, is the dramatic flex of the arrow. In all three clips the arrow does basically the same pattern. But there is some difference in the timing and the degree. It makes it obvious how important spine and centershot tuning are.

Before those clips I didn't realize how far from the plunger and the rest the arrow moved before leaving the bow. So I've got this fancy magnetic Shibuya rest that is suppose the move out of the way when it is brushed by the fletching, but if the bow is tuned right, the fletching should never touch the rest.


----------



## Joe T (Apr 5, 2003)

Very difficult to detect plunger movement from a video not designed to illustrate it. Take a look at the Beiter videos which use a mirror on the plunger.

Whether the plunger moves or not is largely irrelevant. If you throw a tennis ball at a concrete floor, the floor doesn't move but it still has a significant effect on the tennis ball. The plunger produces a sideways force on the arrow. Ideally want this force to be low so you have a low spring preset - and the plunger gets depressed. With very high spring tension (locked up button) you get little plunger movement and large *increase* in the plunger force on the arrow. In general the less the plunger moves the bigger the effect of the plunger on the arrow.


----------



## Vittorio (Jul 17, 2003)

In a well tuned bow, the plunger moves inside and reacts, and this can be filmed easily at 1200 fps (Casio F1). The speed of the reaction is related to the torsion to the string, therefore a well tuned plunger goes "in" faster in a bad release situation, but also reacts faster to it. This is the function of the plunger . Without plunger, reaction to a bad release is purely related to back flexibiliy of the arrow and center shot, a difficult combination to find to make a forgiving set up.
Springs inside plunger dominate the reaction, and a simple one number mesure of their (compressed) force can't give the solution for the perfect tuning, as different springs at different compression have different reactions starting from the same intitial force. Then, there are also (few) conic springs solutions around to give non linear compression/reaction results. 
For sure, a blocked plunger has no use and function, and probably this is what is shown in the movies.


----------

