Author Topic: limb tip design analysis request  (Read 14187 times)

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briarbrow

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limb tip design analysis request
« on: May 09, 2007, 04:37:38 am »
Hello fellow Archers,
I am curious about this limb tip. I'd rather not mention the bowyer, I'm not questioning his knowledge or skill. I have been waiting a couple of days for an email response, but maybe he has gone to the festival in Korea. Some of you may recognize it right away.

only thing, I just don't like the step down. I have seen pictures of this same model in which the tip appears much smaller,  or without the abrupt transition, which I think looks much better. That could be because the picture was small or the bow was braced much lower, the angle etc. I just don't know.

I have wanted one of these for about 4 years but shied away because of the price. I don't want my ideas of what should or shouldn't be to get in the way either. To be honest when I saw this aspect of the bow my enthusiasm waned.

What's your opinion?





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MattE

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Re: limb tip design analysis request
« Reply #1 on: May 09, 2007, 09:41:19 am »
The workmanship looks good but it also looks overbuilt? I think it would impart a lot of hand shock due to the excess weight it appears to have on the tips. I would want to shoot the bow before investing any money.

Offline tom sawyer

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Re: limb tip design analysis request
« Reply #2 on: May 09, 2007, 11:23:42 am »
Hard to tell how narrow it is, if it is real skinny it ought to be alright.  Is it a long horn piece or is it wood?  I suppose they glued it on like a horn nock?
Lennie
Hannibal, MO

Offline samuraiwarrior

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Re: limb tip design analysis request
« Reply #3 on: May 09, 2007, 11:25:14 pm »
The picture is of the tip of a Yumi Japanese bow.  They are usually mulberry, spliced into the body, which is layered hardwood and bamboo, with a solid bamboo back and belly.  They really don't impart a lot of handshock, and your enthusiasm shouldn't wane.  They are very efficient bows.  You could probably expect 185+ fps with 500 gr arrow out of a 44 lb bow.



They are not very thin either, compared to the rest of the limb. Hoewver, yumi are relatively not as wide as most flatbows.  I do not know why they are made like that.  they have been made like this for a very long time, it may have some purpose.  You might contact Jaap Kopedrayer or somebody who specializes in them. 

briarbrow

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Re: limb tip design analysis request
« Reply #4 on: May 10, 2007, 01:48:49 am »
Thank you my friends.

Your replies are in line with my own thoughts.

The similar bows I have seen online are more like the yumi posted by samuraiwarrior. the string contact and end of the "bridge" are at the same point. In that sense I agree with Matt, this one seems a little overbuilt.

Tom I believe the construction is exactly as Samuraiwarrior has described.

fwiw The narrow limb is one of the main features I like of this bow. It is not a yumi. ;)

Offline medicinewheel

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Re: limb tip design analysis request
« Reply #5 on: May 10, 2007, 04:35:05 am »
hey briarbrow!  -  the limb tip is adapted by the samurai bow and for the overall asymmetrical costruction (in combination with very light-weight limbs) these bows  have no exaggerated handshock. it's probably not the kind of bow that gets just everybody excited but you should shoot one to find out.

frank

ps: attached is the pic of one i made the same way, seventy-some pounds at 29", 66"ntn. thisone has not an exaggerated handshock even when shoot with light target arrows.


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« Last Edit: May 10, 2007, 04:56:41 am by medicinewheel »
Frank from Germany...

Offline medicinewheel

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Re: limb tip design analysis request
« Reply #6 on: May 10, 2007, 04:40:10 am »

pps: maybe you want to check my threat here


http://www.primitivearcher.com/smf/index.php/topic,1824.0.html


it's a longbow made using the same sort of core cross section.
Frank from Germany...

Offline Marc St Louis

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Re: limb tip design analysis request
« Reply #7 on: May 10, 2007, 11:42:18 am »
No offence SM but that kind of performance would be spectacular and would be setting records at flight shoots. I think Japp went to a flight shoot last fall with some of his bows. No records were broken
Home of heat-treating, Corbeil, On.  Canada

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Offline tom sawyer

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Re: limb tip design analysis request
« Reply #8 on: May 10, 2007, 11:55:29 am »
Marc, I think the catch is that the Yumi is pulled to a very long draw, much farther than 28".  I think they pull something like 34-35", I know its back past the person's ear.  That'd make a big difference, another 7" of power stroke would be something like 30% more stored energy.  So I could believe the speed claimed.

I think the use of mulberry, since it is a lightweight wood, probably mitigates the potential for hand shock.
Lennie
Hannibal, MO

briarbrow

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Re: limb tip design analysis request
« Reply #9 on: May 10, 2007, 10:43:27 pm »
Hey Medicinewheel. Is the lack of mass appeal because of a finicky nature or something else?


Offline medicinewheel

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Re: limb tip design analysis request
« Reply #10 on: May 11, 2007, 10:38:25 am »
Hey Medicinewheel. Is the lack of mass appeal because of a finicky nature or something else?



hey briarbrow!  -  i do not really understand what the question asks for; please try to say it in a different way if possible!
sorry, i'm german  ???
frank
Frank from Germany...

Offline samuraiwarrior

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Re: limb tip design analysis request
« Reply #11 on: May 11, 2007, 08:46:56 pm »
Marc, you may be right.  The stats were posted quite a while back on ATAR, and I don't know the validity of the test or anything.  But Yumis are not poor performers either. 

Offline Marc St Louis

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Re: limb tip design analysis request
« Reply #12 on: May 12, 2007, 08:44:25 am »
I know they have a longer draw Lennie but as I said, Japp went to the flight shoots last Fall and shot some of his yumis for distance.

I have no doubt that they perform quite well SM
Home of heat-treating, Corbeil, On.  Canada

Marc@Ironwoodbowyer.com

MattE

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Re: limb tip design analysis request
« Reply #13 on: May 12, 2007, 09:49:48 am »
185+ out of a 44# bow would be phenomenal performance. I have never seen a Yumi that could perform this well.I have seen many Japanese made Yumis,I think of them as works of art, especially in the engineering department.They are beautiful bows and perform well but like the long bows of yore fantasy has overridden fact. 

briarbrow

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Re: limb tip design analysis request
« Reply #14 on: May 12, 2007, 11:58:49 am »
hey briarbrow!  -  the limb tip is adapted by the samurai bow and for the overall asymmetrical costruction (in combination with very light-weight limbs) these bows  have no exaggerated handshock. it's probably not the kind of bow that gets just everybody excited but you should shoot one to find out.

frank

ps: attached is the pic of one i made the same way, seventy-some pounds at 29", 66"ntn. thisone has not an exaggerated handshock even when shoot with light target arrows.


Hi,
you say it's not the kind that gets everyone excited. I was asking what are some of the reasons. thanks.