User Tag List

Results 1 to 12 of 12

Thread: New compound bow concept

  1. #1
    SPACE FOR HIRE
    Join Date
    Oct 2004
    Location
    Kempsey NSW
    Posts
    347
    Tournaments Joined
    0
    Tournaments Won
    0
    Post Thanks / Like
    vCash
    500
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Rep Power
    7919

    New compound bow concept

    http://www.archerytalk.com/vb/showthread.php?t=1996632

    Here's one for the engineers, what's your thoughts on the concept? Is the principal correct? How will it affect nock travel etc
    Never look down upon a man unless you are helping him up

  2. #2
    Grand Master Bowman
    Join Date
    Jul 2001
    Location
    Glen Waverley, Australia
    Posts
    9,781
    Tournaments Joined
    0
    Tournaments Won
    0
    Post Thanks / Like
    vCash
    500
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Rep Power
    376421
    I don't see any real value in trying to get to 400 ft/s.

    However: My expectation of trying to extract more energy from the first part of the draw is that it will result in a very sharp impulsive force during the bow's power stroke just before the string gets to its brace height. That could be expected to make such a thing pretty difficult to shoot well.
    Scout strings and stabilisers
    Accurate Sights
    Titan Scopes

  3. #3
    Instinctive Rock Steady's Avatar
    Join Date
    Jul 2007
    Location
    Singleton
    Posts
    211
    Tournaments Joined
    0
    Tournaments Won
    0
    Post Thanks / Like
    vCash
    500
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Rep Power
    15310
    I think it is interesting and like the idea of lowering the poundage yet maintain arrow speed. Instead of a 70# bow for hunting I may only need a 40 or 50# version to maintain 300fps for my hunting arrow weights.

    Michael

  4. #4
    *****istrator Marcus's Avatar
    Join Date
    Jun 2001
    Location
    Bleeding Green
    Posts
    24,663
    Tournaments Joined
    2
    Tournaments Won
    0
    Post Thanks / Like
    vCash
    0
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Rep Power
    965953
    So basically he's added some extra pullies to the bow that cause the initial draw to be heavier.
    Sorry, not buying it.

    Also he seems more interested in the marketing of the product, than the actual product design. A 2lb riser? No thanks.
    Seems like some dude in his basement who has an idea and now thinks he's Matt McPherson.
    Urban Archery

    Before enlightenment: Chop wood, carry water
    After enlightenment: Chop wood, carry water

  5. #5
    Ecky Thump grandmaster scott p's Avatar
    Join Date
    Jun 2011
    Location
    Melbourne SE
    Posts
    1,975
    Tournaments Joined
    0
    Tournaments Won
    0
    Post Thanks / Like
    vCash
    450
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Rep Power
    73512
    Quote Originally Posted by Rock Steady View Post
    Instead of a 70# bow for hunting I may only need a 40 or 50# version to maintain 300fps for my hunting arrow weights.
    great, but what about your holding weight and back tension?

  6. #6
    Administrator dbjac's Avatar
    Join Date
    May 2005
    Location
    Mentone
    Posts
    4,037
    Tournaments Joined
    2
    Tournaments Won
    0
    Post Thanks / Like
    vCash
    375
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Rep Power
    612574
    Also completely useless for target at the moment, considering a 29-30" 60# compound man will likely be shooting ~380 spined arrows already (stiffest spines offered currently).

  7. #7
    Instinctive Rock Steady's Avatar
    Join Date
    Jul 2007
    Location
    Singleton
    Posts
    211
    Tournaments Joined
    0
    Tournaments Won
    0
    Post Thanks / Like
    vCash
    500
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Rep Power
    15310
    Quote Originally Posted by Marcus View Post
    Seems like some dude in his basement who has an idea and now thinks he's Matt McPherson.
    Didn't Matt start in a panel shop? It wasn't till he got investors he moved up in the world and he started with an innovative idea for a radical new cam design?

    I wonder how many bagged him for trying back then?

    Michael

  8. #8
    Instinctive Rock Steady's Avatar
    Join Date
    Jul 2007
    Location
    Singleton
    Posts
    211
    Tournaments Joined
    0
    Tournaments Won
    0
    Post Thanks / Like
    vCash
    500
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Rep Power
    15310
    Quote Originally Posted by scott p View Post
    great, but what about your holding weight and back tension?
    Have a read of the thread, he goes over holding weight.

    Not sure how it changes the effect of back tension on release if thats what you mean.

    Michael

  9. #9
    Ecky Thump grandmaster scott p's Avatar
    Join Date
    Jun 2011
    Location
    Melbourne SE
    Posts
    1,975
    Tournaments Joined
    0
    Tournaments Won
    0
    Post Thanks / Like
    vCash
    450
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Rep Power
    73512
    I read the thread.

    here's the most interesting comments which kill the idea stone dead for me:

    "Where would the peep sight go"

    "I'd assume...no peep. One of the no peep sights would be in order."

    vague hand-waving assertions on this not being a complete derail don't count.



    also, we're assuming that we need 400fps to achieve anything, which we do not.

  10. Thanks James Park thanked for this post
  11. #10
    Administrator dbjac's Avatar
    Join Date
    May 2005
    Location
    Mentone
    Posts
    4,037
    Tournaments Joined
    2
    Tournaments Won
    0
    Post Thanks / Like
    vCash
    375
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Rep Power
    612574
    Further thinking; It will not work (but i'm not a physicist, so flame away).

    A) Target shooters are restricted to 60#, so we will have a significantly reduced force profile thanks to that huge kick at the start. I'd say probably about 50% of the force.

    'So what?', you say, 'this is about 400fps!'.

    B) He's still not going to get 400fps. Ever.
    Sure, he can get 400fps with a 350gn IBO arrow. But sorry, you're hitting 110# draw weight, so you've got to crank that up to 550gn or OH&S will have a heart attack. And that's not going 400fps...
    It will likely hold less force than an 80-85# conventional bow.

    You don't want to create a triangle of force, because that means one side of the curve is under-performing.
    Ideally, you want to create a completely filled rectangle.

    I agree with Pete Shepley.

  12. Thanks James Park, Marcus thanked for this post
  13. #11
    Administrator dbjac's Avatar
    Join Date
    May 2005
    Location
    Mentone
    Posts
    4,037
    Tournaments Joined
    2
    Tournaments Won
    0
    Post Thanks / Like
    vCash
    375
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Rep Power
    612574
    Also imagine the effect on the arrow.
    50% of the force is at ~ normal 70#, and the rest hikes up to 110#.

    So, you're either going to have an arrow that is ridiculously stiff for ~50% of the shot, or one that turns to spaghetti in the final 50%.

    Yep. Terrible idea.

  14. Thanks James Park thanked for this post
  15. #12
    Master of Grumpiness
    Join Date
    Jun 2004
    Location
    Sunny Brisneyland, Oz
    Posts
    1,938
    Tournaments Joined
    0
    Tournaments Won
    0
    Post Thanks / Like
    vCash
    500
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Rep Power
    447957
    Quote Originally Posted by fletcher View Post
    http://www.archerytalk.com/vb/showthread.php?t=1996632

    Here's one for the engineers, what's your thoughts on the concept? Is the principal correct? How will it affect nock travel etc
    My $0:02 worth.

    If the aim of the project is to produce a 400 f.p.s bow/arrow combination okay.

    If the aim is to produce a 400 f.p.s.bow that is fits within the requirements for Target Competition and still be as accurate as current products ...... hmmm ...... starting with a 100% efficient bow/cam system, a 30" draw length and a constant 60lb force (world archery max draw force) - no let off (or perhaps the let off happens in the last 1/4" of draw).....
    Last edited by GrahameA; 14th August 2013 at 04:15 PM.
    Regards, Grahame.

    Believe me, my young friend, there is nothing absolutely nothing half so much worth doing as simply messing about in boats.
    Ratty.
    "Its Not ...... But it Can Be."
    MacKenzie McHale (Emily Mortimer)

    Quod gratis asseritur, gratis negatur.



    Francoise Hardy, Sylvie Vartan, Petula Clark

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •