Author Topic: Tiller/strain/etc  (Read 363 times)

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Offline bownarra

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Re: Tiller/strain/etc
« Reply #15 on: February 15, 2020, 02:11:32 am »
The 'problem' with all this stuff is everything is on a sliding scale. As one thing is altered so something else is affected. As Badger says you should simply avoid set as your primary goal. Most designs when optimized shoot within a few fps of each other, close enough to generally need a chrono to tell the difference. This was why I moved onto hornbows for a new challenge...but guess what.....the same rules hold :)
No set inner limbs, a little mid limb and the rest mid out to the tips still holds true. If you manage this you will have a fine bow :)

Offline DC

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Re: Tiller/strain/etc
« Reply #16 on: February 15, 2020, 09:40:57 am »
I got out my RD BooYew bows yesterday. I have eight. I've made them over the last couple of years. Some of them have gained a few pounds hanging on the wall so a little retillering is in order. Anyway I tested them all as is and they shot between 188-196 fps. I laid them out in order of speed and the only thing that jumps out is that the faster bows have more reflex. I can see that a couple of the slower one could stand a little tip reduction but that doesn't usually net big gains.The last one started at 2 3/4"reflex climbed up to 4 3/4" and then settled at 3 3/4". I'm going to call that low set :D. The nice thing is that the speed gain also seems to follow the order of construction so I must be learning something even if I'm not noticing.Looks like the next one will be a tad wider mid limb and a little more reflex. I am finding that controlling the reflex is a bit of a crap shoot. With limb thickness, wood differences, set and probably a couple more things the amount of reflex doesn't always come out as planned. Like you say Bownarra everything depends on everything else. :D
Vancouver Island
If you don't have any questions you must not be paying attention.

Offline willie

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Re: Tiller/strain/etc
« Reply #17 on: February 16, 2020, 01:22:12 am »
One thing I have noticed when strain is being discussed in bowmaking conversations is that folks with engineering backgrounds understand strain as how much the back or belly is stretched or compressed due to the radius of bend. Of course overcompressing a belly causes set, which all bowyers agree is not desirable. Conversations can become a bit uncertain when folks with differing backgrounds and training use the term strain in a more general fashion or as understood in other disciplines.

A bow with equal strain all along the length of the bow could be understood by some as a circle of arc tiller in something like a  bendy handle. Of course other design factors like stiffer handles or tips add to arrow performance in more geometrical ways with out being strained (from an engineering perspective) very much at all. The circle of arc example above only holds true in an engineering sense of strain,  if the thickness of the bow remains constant and all tapering is done in width. This is not a bow seen very often.