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| POS |
 Posted: 10/25/2006 12:59 PM Post subject: PVC arrow |
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Major
Joined: 14 Sep 2006
Posts: 395
264.52 Spud Bux
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For those who have a 50 mm barrel, you could make a arrow like this one. It is constructed of PVC. The end works as a flight stabilisator. Inside the endring I 'm gonne construct some PET vins in a twisted way, so in flight, the arrow starts to spin, so the ammo flighs more accurate.
The nose cone os the arrow is constructed out of hard isolating foam, 5 cm (2") thick. I putted a piece on a big screw, and put the srew in a dril, and let it turn slowly (relatively slowly) like a improvices lathe. With a file and sandpaper I then formed the nose cone like it is. The cone is then glued in the pipe with ordinary PVC-glue.
There is a hollow space in it, between the tail and the nose cone. You should put things in it to give it a bir of weight, like forinstance a smoke bomb or so.
You can also put is a pressurized water rocket, so when you shoot it, the pressure releases and gives the rocket extra power and speed. The rocket can be equiped wits a parachute that opens on apogee.
Anyway, her's the rocket or arrow :
| Description: |
| Sideway of the rocket. good sight of the nosecone and the stabilizor |
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17.86 KB |
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654 Time(s) |
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| Description: |
| Clear sight on the stabilizer |
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| Filesize: |
18.44 KB |
| Viewed: |
654 Time(s) |
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| Recruit |
| Posted: 10/25/2006 14:41 PM Post subject: |
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Lieutenant Colonel
Joined: 06 Oct 2006
Posts: 415
256.60 Spud Bux
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| Nice rocket, how accurate is it and does it go far?
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| POS |
| Posted: 10/25/2006 14:52 PM Post subject: |
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Major
Joined: 14 Sep 2006
Posts: 395
264.52 Spud Bux
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I 'm gonne test it, hasn't been done for the moment. I 'm going to buy some pressure PVC next month, I have to drive 90 km for that. When I have my gun ready, I let you nof for sure. It is pressty light. According to the GGDT, with a bit of payload, the arrow should fly over 1000 feet.
I dont doubt the fact that it is acurate, since it has a stabiliser and it will spin in midair. I have experience with waterrockets, they are pretty acurate with stabilisers and spinning.
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| schmanman |
| Posted: 10/25/2006 14:54 PM Post subject: |
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blabbering idiot
Joined: 25 Mar 2006
Posts: 1667
1006.17 Spud Bux
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| what size is the pvc? I make my rockets out of aluminum pipe, steel nosecones, and flexible tail fins made from bucket lids.
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| POS |
| Posted: 10/25/2006 15:38 PM Post subject: |
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Major
Joined: 14 Sep 2006
Posts: 395
264.52 Spud Bux
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post a pic man, I'm curious.
The PVC is 50 mm. But I plan to build a 43 mm barreled pneumatic, so I have to take an other pipe.
What size are your darts ? And what is the use of them ? I make them out of PVC, so they are extra light. The arrow you see up there waighs exacly 100 gram. So room enough for a payload like a smokebomb or something. That should be nice in midair.
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| schmanman |
| Posted: 10/25/2006 19:00 PM Post subject: |
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blabbering idiot
Joined: 25 Mar 2006
Posts: 1667
1006.17 Spud Bux
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| mine are 2-3 feet long, and are used for shooting for distance with my big cannon.
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| Slugfoot |
| Posted: 10/25/2006 22:32 PM Post subject: |
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Specialist
Joined: 21 Oct 2006
Posts: 58
137.13 Spud Bux
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| Nice one!......but wouldn't spinning it actually de-stabilise it?
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| weirdwun |
| Posted: 10/26/2006 9:23 AM Post subject: |
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Private
Joined: 14 Feb 2006
Posts: 14
8.62 Spud Bux
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| no.....I understand what you're saying, but it does stabilize it.... it's hard to explain. He's talking about spinning on its vertical axis not the horizontal.
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| Posted: 10/26/2006 9:48 AM Post subject: |
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Lieutenant Colonel
Joined: 06 Oct 2006
Posts: 415
256.60 Spud Bux
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The arrow spins like a top does. That spin is generated by bullets which
is one of several things that stablize them all that is basically is making a
big bullet that will generate this spin better
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| POS |
| Posted: 10/26/2006 13:42 PM Post subject: |
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Major
Joined: 14 Sep 2006
Posts: 395
264.52 Spud Bux
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Ok, I'll try to explane what spinning does to the arrow to stabilise it:
The arrow isn't perfectly ballanced in vertical direction I mean. I mean that the left side, the right, the front and backside cant be EXACLY the same. Therefor the arrow will lose track, due to the difference in weight. If left side is a gram heavier that the right side, the arrow wil deviate to the right, cause the extra weight keeps "pushing" the arrow forward, it has more energy (E = MC˛) The right side is lighter than the left side, so it slows down faster due to air friction. The result of this is that the arrow turns slowly to the right.
So, when the arow doesn't spin, the arrow will deviate to the right, but due to the spinning, the right becomes the left, back the right, left right ... So the deviation also alters from right to left to right ..... resulting in a straight flight.
Got that ?
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| boilingleadbath |
| Posted: 10/26/2006 15:33 PM Post subject: |
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Moderator
Joined: 12 Mar 2005
Posts: 1647
5491.22 Spud Bux
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...the formula you are looking for is E=1/2 MV^2.
MC^2 is for a special case (light)
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| Hotwired |
| Posted: 10/26/2006 15:50 PM Post subject: |
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UK Spudgunner
Joined: 13 Oct 2006
Posts: 1800
3889.01 Spud Bux
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That would be interesting 
Mass x speed of light^2 = energy of spudgun rocket 
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