Sling x bow Cannon 3D render

Discussion in 'New project ideas' started by BrooksPotts, Oct 6, 2013.

  1. BrooksPotts

    BrooksPotts Brooksiepooh

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    Hey there gents!

    Name is brooks I'll introduce myself on the boards here in a bit, but I told J.S. I'd post some cool ideas for you rubber heads on here.

    Hope you guys like the idea, I'll keep doing some work on them and you guys let me know if you want to see anything extra and I most deff dont mind commision work!

    :p
     

    Attached Files:

  2. Cadman

    Cadman New Member

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    All I see are blank pdf files.
    :mad:
     

  3. onnod

    onnod Im from Holland, isnt that weird?

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    welcome!

    it seems my PDF-reader can't open your files because they are in 3D
     
  4. Tremoside

    Tremoside SINdustrial designer

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    It's not a render and without UVW info but a 3D pdf. Maybe a newer version of Adobe Reader can handle it to you.

    Attached a Prnt Scrn

    y wing cannon slingshot2.jpg

    Maybe some baked shadows and wood texture could help to better understand the mechanism.

    BTW Welcome and thanks for sharing :)
     
  5. JoergS

    JoergS Administrator

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    I have some remarks.

    A normal fork does not work well, as the pull on the fork tips will cant the whole sled and cause a huge amount of friction. Rails like those I used on my cannon are much better, all of the forces are in line.

    I don't understand your trigger/lock mechanism - looks just like a tube to me. Or is that the scope, and the trigger/lock details are just not visible? On a cannon, much thought needs to go into the trigger/lock assembly. The draw force is very high. You want strength, functionality and smooth operation.
     
  6. BrooksPotts

    BrooksPotts Brooksiepooh

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    I agree 100% and yeah this is extremely unfinished. The trigger mechanism will set like a midieval heavy crossbow, and so will the block and tackle system as well. I'm on my way to get some textures into the model and also the fork design isn't for sure but it should still work, if friction is our enemy then overcoming it on wood has a simple solution, possibly inset ball bearings or something with less contact but has fairly smooth operation.
     
  7. BrooksPotts

    BrooksPotts Brooksiepooh

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    And sorry for the PDF files guys the site wouldnt allow me to post the images even after I fixed the sizing and file KBs. But with the new version of Adobe you can view 3D imagery
     
  8. FIAAO

    FIAAO Failureisalwaysanoption

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    I can see it! :) Looks cool, but I agree with Joerg on the forks-issue; With forks like those on his cannon you will never get any forkhits!
     
  9. BrooksPotts

    BrooksPotts Brooksiepooh

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    Okay guys edit on the model, changed the rear end a bit to house the wheel lock mechanism. To identify these mechanisms on the catapult theyll be in green. The rest are browns and lights brown colors.
     

    Attached Files:

    Last edited: Oct 7, 2013
  10. BrooksPotts

    BrooksPotts Brooksiepooh

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    Hmmm so forks are no good.... what about a squared fork? Or is that just beating a dead horse?

    Basically to attached posts to a base instead of a Y shape
     
  11. JoergS

    JoergS Administrator

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    Just watch my cannon video - the inline rails and the "toilet seat" fork solve that problem. Bearings won't work, the strain will be too high and they would break in no time.

    [ame]http://www.youtube.com/watch?v=_AySuafZ8to[/ame]

    Block and tackle aren't really needed - you can simply increase the handle length of the crank.

    Your crossbow lock and trigger would work, but of course you need to round everything well. I think my lock and trigger design is just a whole lot easier to make, don't you think?
     
  12. BrooksPotts

    BrooksPotts Brooksiepooh

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    Most definitely I like your design, when it comes down to it the toilet seat makes for a good joke regarding getting "prince alberted" lol, ( and i think its just a personal touch on my end) but I absolutely agree with you on the control panel setup you have as far as everything being controlled in front of you, one thing I was trying to avoid was to much stuff sticking out, which the long handles was one of the things I wanted to avoid as much as possible. The block and tackle idea came about because I was hoping to make the slingshot as powerful if not slightly more than your current setup ( your feed back on that would be extremely grateful). I'll need your opinion on that one because I dont know to much about the types of rubber and what would be a good choice.... hmmm maybe my idea is more midieval than I seem to realize. Regardless Im going to dump the forks Idea as it is clear it wont work too well and go with something a little longer and more crossbow-ish. I'll repost the design once it is complete. BTW thank you guys for your knowledge and feedback :)
     
  13. JoergS

    JoergS Administrator

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    You can certainly increase the power, block and tackle will work - but slow down the cocking procedure. Maybe you should simply use a 12V winch for offroad cars, those are cheap and canbe operated by a car battery. Some models have 2000 kg = 4400 lbs force, way overkill.

    I recommend using Thera Band Gold, good performance and well protected against sunlight. Only natural latex rubber has a (slightly) better performance, but will break down very quickly if exposed to sunlight and heat.

    As far as the draw weight is concerned, this depends on the ammo you want to shoot. My cannon has 2,6 m effective draw, about 8ft. At that draw length I recommend 250 to 400 times the weight of the ball. For olympic (men's) shot put, 7,5kg times 400 = 3,000 kg. For boule balls, 0,8 kg times 400 = 320 kg. One full band of TBG has 18 kg.

    A longer draw reduces the required draw weight, pretty much in a linear fashion.

    Good luck!
     
  14. pelleteer

    pelleteer Middle Aged Delinquent

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    If you're going to use a medieval crossbow style roller nut lock like that, you'll want to have the fork more in line with the path of the pouch. If you prefer not to use the toilet seat style, I'd at least lower the fork so that the bands, pouch, and ball travel just over the "barrel" or main rail of the cannon. I'm picturing something like this one:

    [​IMG]
     
  15. JoergS

    JoergS Administrator

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    Again, if you want to use a sliding fork, it MUST BE in line with the band's power vector. At a draw weight in excess of 250 kg (the fun starts at that point), the canting will otherwise jam it in place quickly, no matter how well you grease it. Even ball bearings won't work, not at that draw weight.

    I have done plenty of tests with sliding forks and/or sliding locks. The only thing that works is inline, through the "fork" (or toilet seat).
     
  16. BrooksPotts

    BrooksPotts Brooksiepooh

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    I see! SO really we are talking here about the way the wenching system is going to be under a lot of pressure because of the draw weight and the position of the trigger mechanism?! Especially I could imagine how the independent fork moving up the shaft (hahaha shaft and fork) ends up getting to a point where the draw weight and the position of the wench wont have enough length to place the fork into the trench where its supposed to remain during firing? now that could be a problem! I'm thinking for sure, but here is an update on the design and how far it has come along!
     

    Attached Files:

  17. JoergS

    JoergS Administrator

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    How is that changing the issue of canting? See picture.

    Maybe I don't understand, the sketch seems to be unfinished, several details are unclear.
     

    Attached Files:

  18. BrooksPotts

    BrooksPotts Brooksiepooh

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    Its a work in progress, and I see the friction points however these are just small updates do the design this isnt a final product JS so dont stress out :p

    I can see your cogs spinning from her (=,=)
     
  19. Tremoside

    Tremoside SINdustrial designer

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    Don't take me seriously I'm not a builder of slingshot cannons.

    Slingshots and rubber powered shooters are based on real life experience. Most of the people here starting with copying the masters. Just as in fine art when you searching your own style. During way seeking you can build up your own know-how. And I'm talking about the actual grinding, drilling, cutting aspect.

    I'm using CAD daily and sometimes starting my ideas with that as soon as possible I try to get to proportions and general (rough as possible) ideas. Then full speed ahead to the workshop. CAD is not real life, fine for sketching or producing engineering data, but damn far from real life experimenting.

    You have the 3D skills, and it seems you want to find your own solution. The only thing why I write this that it's a huge project.

    You have to find proper building materials, time schedule, place to build, shipment / transport, tools. It must be as safe as possible also. Safe to use, safe to build.

    If I were you I would start with a downscaled model. Following existing methods. It's not a shame to try to build what Joerg did already. With collected experience it's way easier to manage a huge project like this.

    You got great support form Joerg here! It's a value, use that wisely.

    Excuse me for the critics but it's only to move this project forward.

    Have a nice day,
    Tremo
     
  20. Slagskimmer Mike

    Slagskimmer Mike thinks TBG smells better than roses

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    Beautiful drawings and thumbs up for wanting to bring this into the world!

    This will be a cannon of epic energy and force.

    Like Tremo said, copying the masters is no shame--all true masters stand on the shoulders of giants.
    I learned so much just executing plans already proven out (M10 hexnut gun).
    The ideas I get while in the shop building blow away any I ever got in the Armchair.:D

    I hope this badboy makes the transition from model to reality--go big or go home. Just keep safety first so the next one can be bigger yet.

    edit: Oh, welcome to the forum, btw--I welcome the eye candy you brought with too:cool:
     
    Last edited: Oct 8, 2013