Author Topic: How does this tiller look?  (Read 1303 times)

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Offline willie

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How does this tiller look?
« on: October 12, 2017, 01:22:35 pm »
this is a pic from Physics of Bows and Arrows Paul E. Klopsteg

I would say the tillering  job looks good, but what limb shape is it best for?

Offline Mo_coon-catcher

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Re: How does this tiller look?
« Reply #1 on: October 12, 2017, 01:49:23 pm »
The lower limb looks a smidge stiff to me. It looks like the bow is tilting downward and the string angle isn't quite the same. But that's going off of an even unbraced profile.  I'm leaning more towards a pyramid profile. For a parallel limb I'd want a tiny bit more stiff at the inner quarter to third.

Kyle

Offline bradsmith2010

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Re: How does this tiller look?
« Reply #2 on: October 12, 2017, 02:15:31 pm »
 (-P

Offline Hamish

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Re: How does this tiller look?
« Reply #3 on: October 12, 2017, 02:39:59 pm »
The tiller is acceptable(good assesment by Kyle), but its hard to make a judgement not being able to see the same bow, at brace, unbraced, or the design of the limb.
Is this bow one of Klopsteg's own bows made by his hand? I'm skeptical of all the authors /physicists that championed a scientific way of designing a bow as being the best way to make bows. The bows that I have made following their recommendations turn out pretty average. I would have done a better job doing it all by eye. Wooden bowmaking is more art than science due to natural variation in wood.

mikekeswick

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Re: How does this tiller look?
« Reply #4 on: October 12, 2017, 02:46:21 pm »
Easy :)
Pyramid

Offline willie

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Re: How does this tiller look?
« Reply #5 on: October 12, 2017, 02:55:46 pm »
Hamish

 the pic is from a magazine article about various aspects of the bow and arrow. No special claims were made for the bow, as the pic is shown in an explanation of stance and aiming.

I just got curious because no other pics were available, and I like the bow
« Last Edit: October 12, 2017, 07:28:12 pm by willie »

Offline Dances with squirrels

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Re: How does this tiller look?
« Reply #6 on: October 12, 2017, 03:32:50 pm »
In this instance, it doesn't really matter what the unbraced or braced profile looks like. The bottom limb is too strong, the limbs aren't dynamically balanced. Notice how the bottom isn't flexing near as much as the top. Since it isn't moving as far as the top limb, the stronger bottom limb is pulling the string hand and tail end of the arrow downward, and is noticeably below perpendicular to the shelf. I bet that arrow porpoised on its way to the target. Look at the picture sideways. It's more apparent that way.

If the limbs were balanced, the arrow would come straight back, effectively maintaining its height relationship with the shelf, and in all probability, would be perpendicular or sightly above perpendicular. I highly doubt if he nocked that arrow an inch below the shelf to begin with. I also wouldn't be surprised if that bow's tiller changed.... bottom limb got weaker with use.

Offline Selfbowman

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Re: How does this tiller look?
« Reply #7 on: October 12, 2017, 06:18:01 pm »
Well he is known too be one of the best at his time. So I would say good. Looks like a field archer to me. Sting walker also possible . I don't really know but my guess. :-)  Arvin
Well I'll say!!  Osage is king!!

Offline bentstick54

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Re: How does this tiller look?
« Reply #8 on: October 12, 2017, 06:44:59 pm »
How much does shooting split finger, anchoring below jawbone affect the full draw profile?

Offline willie

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Re: How does this tiller look?
« Reply #9 on: October 12, 2017, 08:01:04 pm »
Quote
I highly doubt if he nocked that arrow an inch below the shelf to begin with
you have a good observation, DWS. The arrow seems to be nocked at what would be level with the shelf, (deduced from a few measurements from the pic)  I suppose that I would have to look at it a bit harder if it was on my tillering tree.

In the same article he does mention a pyramid bow designed by hickman with this force draw curve
https://www.google.com/patents/US2100317
wonder how it shot?
« Last Edit: October 12, 2017, 08:10:23 pm by willie »

Offline Pappy

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Re: How does this tiller look?
« Reply #10 on: October 13, 2017, 01:12:36 am »
Bottom limb looks a bit stiff mid limb, other than that looks fine to me. Brad  ;D ;D ;D ;D  (-P
 Pappy
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Offline George Tsoukalas

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Re: How does this tiller look?
« Reply #11 on: October 13, 2017, 01:21:06 am »
Tiller is very good. Lower limb is shorter giving the appearance of being too stiff. Jawge
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Offline stuckinthemud

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Re: How does this tiller look?
« Reply #12 on: October 13, 2017, 02:35:56 am »
Bow is also being aimed slightly upwards adding to the illusion

Offline burchett.donald

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Re: How does this tiller look?
« Reply #13 on: October 13, 2017, 04:35:19 am »
 Looks like positive tiller from here...I also think the photographer was kneeling...Noticed arrow length, nothing showing shaft point in picture...Looking at anchor and wondering if he's a gap shooter or instinctive...Looks like a tournament shot from 60 yds, the "American round" gap shooting...
                                                                                                                           Don
Genesis 27:3 Now therefore take, I pray thee, thy weapons, thy quiver and thy bow, and go out to the field, and take me some venison;

Offline Dances with squirrels

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Re: How does this tiller look?
« Reply #14 on: October 13, 2017, 05:07:13 am »
Relative limb balance has been at the forefront of my bow building for a long time, I almost wish it hadn't been because it drives me nuts sometimes... but yeah, I notice stuff  :o

Arvin, I was taught by some of the 'best of their time' to take none of this for granted, question everything, everyone, and that includes fairly and objectively critiquing the work of others, but especially those who offer instruction, or have good reputations. Who better, and what better way to improve our own understanding and craftsmanship?

Willie, the arrow MAY have been nocked level with the shelf(we'll never know), but the arrow won't STAY level with the shelf as the bow is drawn if the limbs aren't balanced with one another and the archer's holds.

Jawge, I measured them as best I could. The limbs appear to be the exact same length.

Stickinthemud, I don't think there's an illusion that something's wrong, more likely that the bow being aimed slightly upwards helps hide the fact that there's an imbalance.

Donald, positive tiller is a judgment/presumption made at brace height, that is 'supposed' to result in a dynamically balanced bow at full draw, is it not?