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post #1 of 8 (permalink) Old 02-24-2012, 10:29 PM Thread Starter
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Crossbow engineering question

Vertical bows have cams with in excess of 80% let-off. Why don't crossbows utilize the same technology? With trigger mechanisms having to cope with much less holding force I can see no reason why we couldn't have rifle-like trigger pulls measured in ounces rather than pounds if we so desired.
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post #2 of 8 (permalink) Old 02-24-2012, 10:47 PM
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Re: Crossbow engineering question

The compounds do utilize the same technology with less hold weight to a degree than peak draw weight. The recurve styles hold thier full wieght at the trigger latch.

With that said, crossbow triggers still hold tremendous forces at the latch so trigger pulls all on the heavy side. Several manufacturers are adrressing your suggestions though with redesigned triggers that allow much lighter pulls.

I think this will be a direction we see crossbows go as trigger designs improve. It is a heck of a liability though with crossbows. There is alot of force stored in the limbs. Not only is the user concerned with where the weapon is pointed, but that all fingers and appendages are clear of the rail at all times.

Bowtech went with a new trigger design that did not hold the entire weight of the limbs. They had to recall it soon out of the gate. Winchester tried as well but had to redesign the trigger which resulted in the pull being heavier.

As far a letoff is concerned. Compound crossbows have it but I suspect that not on the same level as compounds becuase the power strokes are half of a typical compound. 80% let off cams may not produce enough force in such a short stoke to generate the desired speed.

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post #3 of 8 (permalink) Old 02-25-2012, 12:50 PM
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Re: Crossbow engineering question

We will see better triggers in time. The main reason we haven't seen them yet, probably has to do with liability issues. Same reason my motorcycle engine dies when I put the kickstand down and it won't start unless I pull the clutch in.

To get an 80% letoff in a crossbow and still get the speed that everyone wants has to do with the power stroke and overall length of the crossbow. Darton and Crosman have the highest letoff of any of the crossbows I've tested. Heft a Crosman and you will know that it might not have been the best solution. Darton uses a bull pup design that is much more user friendly. Cocking a crossbow with the very long powerstrokes isn't something that most people want to do, so most of the designers have stayed away from that. Short, lightweight and compact crossbows seem to be where the market is headed.

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post #4 of 8 (permalink) Old 02-26-2012, 11:56 AM
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Re: Crossbow engineering question

Quote:
Originally Posted by arrowhead
Short, lightweight and compact crossbows seem to be where the market is headed.
That's EXACTLY what I want. Lightweight (less than 6 #). Compact (A foot wide or so when cocked). Quiet (mine sounds like a small caliber rifle). Fast (350 +). Adjustable (LOP and fore end for small or large frame shooters). Reliable (no screws falling out or loosening of key parts). Service (Excellent service center for dealers and consumers). What did I miss???

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post #5 of 8 (permalink) Old 02-26-2012, 12:29 PM
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Re: Crossbow engineering question

Better triggers.

I wish the focus wasn't on speed by some of the manufacturers. There is so much than can be improved with crossbows before the need for more speed. Even with all of the ridiculous speed bows out there, I prefer 330fps and feel it the sweet spot with todays technology.

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post #6 of 8 (permalink) Old 02-26-2012, 04:43 PM
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Re: Crossbow engineering question

Things began getting weird with crossbows when they broke the 300fps barrier....but speed sells.

I always got a chuckle out of the emphasis put on ftlb of energy by some. I have seen quite a few bolts run through deer over the years and I can't say I ever saw evidence of hydrostatic shock or energy tranfer in any of them. Once you reach the point of pass-thru the rest doesn't mean diddly.

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post #7 of 8 (permalink) Old 02-26-2012, 05:36 PM
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Re: Crossbow engineering question

i had my excalibur exocet 200 trigger polished done by a factory authorised guy and made a hugh improvement over there stock trigger....not in it that it made a lighter poundage pull, but a heck of a lot smoother where it feels lighter by weight....in fact it surprize's me when it lets go instead of knowing i have to drag it a bit before release........bob

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post #8 of 8 (permalink) Old 02-26-2012, 05:39 PM
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Re: Crossbow engineering question

Quote:
Originally Posted by SigPro2340
Things began getting weird with crossbows when they broke the 300fps barrier....but speed sells.

I always got a chuckle out of the emphasis put on ftlb of energy by some. I have seen quite a few bolts run through deer over the years and I can't say I ever saw evidence of hydrostatic shock or energy tranfer in any of them. Once you reach the point of pass-thru the rest doesn't mean diddly.
all my deer the 4 i did shoot since my crossbow found it's home with me, all have been pass through with me finding my arrow 20 yards past where the deer was standing at shot....two just walked away not even knowing what happened when they fell........bob

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