Weight for string silencers

[nmaier000]

I have 2 string silencers which is the rubber strands and I weighed them on my scale at 39 to 40 grains each and so far everything that I have weighed is just about exact. In the program do I put down 80 grains in the spot for silencers. Also, I have string nocks that are weighing 7 grains each does this sound right to you?

[PSI]

>>do I put down 80 grains in the spot for silencers
It depends on how close to the cams/idler the silencers are. If they are within 3"-4", you can generally put less than the full weight as they tend to act more like "speed balls". If the silencers are way out in the middle area of the string (nearer the serving than the cam/idler), then use the full weight.


>>string nocks that are weighing 7 grains
If by string nocks, you mean brass nock set, yes...that's about right.

[nmaier000]

Thanks Larry you've been a great help

[tovli]

I just called Hoyt/Fuse to find out the weight of the StringShox silencers that come with Hoyt factory strings. They didn't know officially, but put two of them on a scale - 0.24 oz ~ 105 gr total or 52 gr each.

On the Selena they are 5.9" from cams which is 18% of ATA. I have seen recommendations for "around 16% of ATA from cams" so I'm guessing these have no speed ball effect.

[PSI]

I would agree that there's probalby little speed ball effect, but I'll bet they really quiet things down. :-)

The latest version of the program has a field for entering the silencer distance from cam...labeled "Silencer DFC" on the Equipment/My Setup tab.

I wonder if Hoyt's IBO velocities reflect a "bare string" or with silencers.

[tovli]

The silencer field seems to have an 80gr maximum. It resets to 80 after I enter 105 grains and try to save or switch panels.

Also, I'm trying to understand the following (Hoyt Selena 29 lbs):
Equipment panel: no silencer 197 fps estimate, 80gr silencers 191 fps (expected result)
Calibration panel: no silencer 195 fps estimate, 80gr silencer 197 fps
(unexpected but not significant difference really) I'm going to be able to measure it, with silencers, next week.

[PSI]

>>The silencer field seems to have an 80gr maximum

Yep. Most fields have a range of "OK" values..min/max. I'll up the max for that field.

>>Calibration panel: no silencer 195 fps estimate, 80gr silencer 197 fps

Not sure what you're referring to, here...

[tovli]

Explanation:
When I include the 80gr for silencers on the equip panel
Go to Calibration->SightScaleMarks->enter distances+sight settings
computes 197 fps for estimate
Go to Equipment->put 0 for silencer weight,
Go to Calibration->SightScaleMarks->same dist+sight settings
computes 195 fps (implying the arrow speed is faster with silencers)

So the calibration panel estimates higher arrow speeds with silencer weight than without (unexpected). The Equipment panel estimates lower arrow speeds with silencer than without, like I would expect

BTW, I got a new toy yesterday. I measured the speed this morning with my new radarchron - average reading: 198 fps (+/-2% stated accuracy)
so again I am very impressed with OnTarget's estimation ability.

Thanks for devoting your time to creating and maintaining such a great program.

[PSI]

tovli,

The Equipment tab calculation is done using the stated IBO velocity and applying adjustments for variances in DL, DW, arrow weight, etc...

The Calibration tab Velocity from Sight Scale Marks is essentially a different calculation. It generates a velocity from a trajectory that matches your sight marks. The key for this calculation is the how you've defined the arrow, and to a lesser extent (but still important), peep height and sight radius.