Few Bow Questions?

[jdeleon]

Hey Guys i have a few questions for anyone who wants to answer.
First. when it states Say 80% let off does it mean holding 80% of draw weight when holding a full draw or holding 20%.

second. what is better to get the maximum performance out of a bow more let off or less?

third. at what point does an arrow reach its maximum velocity. at the moment released when it leaves the bow or 20feet from the bow. ( is there a chart that would explain this )

Fourth. i have a short DL 26" and have it set at 65# at the same draw weight but if i had a longer DL say 29" will there be a faster arrow.

final when an arrow states 400Gr. is that 400 per inch or total. of the arrow before its cut.

thanks guys!!

[Hookem2255]

No expert...but ill take a shot at some of these


First. when it states Say 80% let off does it mean holding 80% of draw weight when holding a full draw or holding 20%.

- You are holding 20% of the peak draw weight while at anchor.

second. what is better to get the maximum performance out of a bow more let off or less?

-More let off, easier to hold back and steady...especially if your waiting on a shot to present itself.
-Less let off, should produce more speed.

third. at what point does an arrow reach its maximum velocity. at the moment released when it leaves the bow or 20feet from the bow. ( is there a chart that would explain this )

- I would have to guess that as soon as the arrow leaves the string it starts to decelerate.

Fourth. i have a short DL 26" and have it set at 65# at the same draw weight but if i had a longer DL say 29" will there be a faster arrow.

-Yes, the bow will have a shorter "power stroke" where it is putting force into the arrow. Assuming the arrow weights are not that much different.

final when an arrow states 400Gr. is that 400 per inch or total. of the arrow before its cut.

- Total

[GregO]

Holding 20% of the draw weight
Basically, less let-off will get you more speed, all things being equal. But there's more to understand here...

All projectiles are losing speed as soon as they stop accelerating, so highest velocity is as it leaves the string.
The “400” on your arrow refers to the spine, which is a measure of stiffness. It’s not an indication of the weight.

[Hookem2255]

The “400” on your arrow refers to the spine, which is a measure of stiffness. It’s not an indication of the weight.

I wondered this after I posted....Your arrow should have a Grains per inch...or GPI number. That's how you will find out how much your arrow should weigh (completely bare) once its cut to size.

[jdeleon]

Thanks guys this answers my questions.

[oktx]

400 is the spine. It may say like 8.2 gpi. Grains per inch.

[Bill]

All things being equal an 80% letoff cam on the same bow will be faster than a 90% letoff cam since more kinetic energy is stored in the limbs to transfer to the arrow (High school physics- energy can not be created or destroyed, but transformed). Since there is vibration, friction and sound generated it's not a 100% transfer. However, comparing 2 different bows with different let off % is comparing apples and oranges. In my opinion.

[jdeleon]

All things being equal an 80% letoff cam on the same bow will be faster than a 90% letoff cam since more kinetic energy is stored in the limbs to transfer to the arrow (High school physics- energy can not be created or destroyed, but transformed). Since there is vibration, friction and sound generated it's not a 100% transfer. However, comparing 2 different bows with different let off % is comparing apples and oranges. In my opinion.

Very good point. thanks.