Haven't read/looked the links, but sounds like a variant of the repeating c=
rossbow
https://en.wikipedia.org/wiki/Repeating_crossbow
Used by the Chinese and I believe the Romans as well. I recall a TV documen=
tary where some archaeological historians in the UK built an example of Rom=
an one, and were getting away several arrows/minute.



> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
> Of RussellMc
> Sent: 10 March 2017 13:19
> To: Microcontroller discussion list - Public. <piclist@mit.edu>
> Subject: [OT]:: Fully-automatic crossbow.
>=20
> Thought about [TECH] ... :-)
>=20
> Not as "cool" as Van Helsing's one.
> And probably as much (or little) 'draw' as his.
>=20
> BUT, it really works.
> This one is electric powered (electric drill).
> Van Helsing's was gas powered.
>=20
> If you were throwing wooden 'stakes' at Vampires, this one may be as
> effective, or not, as VH's.
>=20
> Needs work. Lots. But, it works
>=20
>                 https://youtu.be/tbKGjRoSofA?t=3D105
>=20
> ______________________________
>=20
> *Van Helsing's version.*
>=20
> I've seen people saying that VH's version is NOT a 'real' cross bow - tha=
t the
> bow arms are cosmetic and do not participate in the action.
> I'd have to watch the movie scenes to check but this "Replica" seems to d=
o
> things properly.
>=20
>     https://youtu.be/5BEZX6AprZI?t=3D17  <- Excellent 44s video of replic=
a "in
> action".
>=20
> People also suggested the Van Helsing draw energy was inadequate to be
> useful. Given that we don't know what version of Hollywoodium is used in
> the bow or the cylinder pressure, some wildguesstimates are in order. If =
the
> pressure cylinder is 500cc and pressurised to 1000 psi (100 MPa) then sto=
red
> energy is about 100 kJ for Adiabatic expansion and about 350 kJ for
> isothermal. Absent a blowtorch / heater assume ~=3D adiabatic and 100 kJ.
> Lower pressure =3D lower energy (of course).
> *Gas energy calculator
> <http://www.tribology-abc.com/abc/thermodynamics.htm>*
>=20
> A 9mm pistol manages around 500 J muzzle energy and a 357 magnum about
> 900J.
> Even 200J would be exceptionally high for a crossbow bolt.
>=20
> At 100% energy usage a 100 kJ reservoir gives about 500 shots.
> Even at 20% overall that's 100 shots.
> He may have to recharge between takes on occasion :-).
>=20
> __________________________
>=20
> *Bow images:*
>=20
> Very good:
> https://cdn.globalauctionplatform.com/b2e3b1bd-9348-4b73-98fc-
> a67400b6d7d3/918d9dd6-dfe5-43c7-ba54-ab7741917cc6/original.jpg
>=20
> 3D model ?  https://www.behance.net/gallery/5109065/CrossBow-
> Modelagem-3D
>=20
> https://4.bp.blogspot.com/-
> 720Xwq0gsoo/V9Mm3SrbSJI/AAAAAAACZiM/LeLaLsYS634I_uHdjBbmQPpAA
> HWg080jgCLcB/s800/Van%2BHelsing%2BCrossbow.jpg
>=20
> *VH with bow*
>=20
> Large. Good detail of mid section
> https://s-media-cache-
> ak0.pinimg.com/originals/1d/d4/ac/1dd4aca75ebfe4a8cb92553e07e26f92.jpg
>=20
>=20
> https://forwhomthegearturns.files.wordpress.com/2013/12/crossbow.png
>=20
> http://www.wallpaperup.com/uploads/wallpapers/2013/10/28/166475/big_t
> humb_72e0eec40a9f4304bf2ce05da90dcb2e.jpg
>=20
> http://4.bp.blogspot.com/-u3J5UW2tJTA/Th2Y_jtO-
> wI/AAAAAAAAAWA/QM_2qV_T9NM/s1600/Jackman%2BVan%2BHelsing.jp
> g
>=20
>=20
>=20
>=20
> *MANY more images
> <https://www.google.co.nz/search?q=3Dvan+helsing+crossbow&espv=3D2&tbm
> =3Disch&source=3Dlnt&tbs=3Disz:l&sa=3DX&ved=3D0ahUKEwjT7uHV-
> cvSAhXKqlQKHdHDARsQpwUIEg&biw=3D1280&bih=3D713&dpr=3D1.5>*
>=20
> & *more
> <https://www.google.co.nz/search?q=3Dvan+helsing+crossbow&tbm=3Disch&tb
> s=3Drimg:CVAFz4QP00x0Iji3eng7kSSCEkw0Thj5UBtTkssew55VM-
> FJBSZHLKHjMWBv-
> lpXqcbg6cU6mNzWL0QSbFOwWE17mCoSCbd6eDuRJIISESwZ5JXagDesKhIJTD
> ROGPlQG1MR0ylTb9RKxr0qEgmSyx7DnlUz4RFjlDFTupPiYSoSCUkFJkcsoeMxE
> WjlAgyPhkjtKhIJYG_16WlepxuARbHONUXLYsi4qEgnpxTqY3NYvRBEoNR6TnZ
> mjbSoSCRJsU7BYTXuYEVsND_1c8gk-T&tbo=3Du&sa=3DX&ved=3D0ahUKEwib0NHw-
> cvSAhXCHZQKHQXMCiQQ9C8IGw&biw=3D1280&bih=3D713&dpr=3D1.5>*
> --
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