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Post by Clayton on Nov 9, 2013 15:24:38 GMT
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Duff
New Member
Posts: 20
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Post by Duff on Nov 15, 2013 11:19:41 GMT
Wow, that is a serious piece of founding.
Any plans to fire the cannon?
Duff
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Post by Clayton on Nov 15, 2013 12:16:39 GMT
I think that this project was always meant to produce a functional Vasa cannon. I think the ones recovered with the wreck might also work if you wanted to fire them, but since they are originals they arent for obvious reasons.
It is an amazing project, and wish I could see part of it in person!
Clayton
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Post by fredhocker on Nov 19, 2013 9:45:53 GMT
We will cast the bronze gun this Friday, at 10 AM, in Tierp (north of Stockholm). I was there yesterday helping with the final cleanup and preparation of the mould. There should be some press coverage, as well as a full account in Tom Ward's blog. The iron gun last week was a test of the mould and foundry logistics. The plan is for a full series of ballistic trials on an instrumented proving range to assess range, accuracy and effect. Some of the rounds will be fired at a replica section of the side of the ship, to evaluate both how effective the gun is and how Vasa might have stood up to cannon fire. Test firing is currently planned for next summer, but that may change depending on range schedules and funding (it will cost about 1 million kronor/150,000 USD to do the trials). There will be film taken, both conventional and high speed, as well sound, doppler radar, pressure monitoring. Think an order of magnitude above a Mythbusters project.
Fred
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Post by Clayton on Nov 19, 2013 12:25:51 GMT
Very cool Fred! I wish you and Tom and anyone else involved in this project a lot of luck on Friday!
Clayton
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Post by matti on Nov 20, 2013 20:17:41 GMT
Man, those ballistic test series will be so cool!!! What a dream to see that in person...
/Matti
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Post by fredhocker on Nov 25, 2013 8:11:34 GMT
The gun was successfully cast this past Friday at Tierps Järnbruk. We started heating about 2.4 tons of bronze around 8 am and poured at about 11. No difficulties, and we expect to take it out of the mould late this week (it takes about a week to cool down). Pictures should be posted on Tom Ward's blog today or tomorrow (http://www.vasamuseet.se/creating-the-cannon). Fred
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Post by Clayton on Nov 25, 2013 18:06:17 GMT
This is good news! Cannot wait to see the finished gun out of the mold!
Keep us updated on when the test firing is going to happen.
Cheers! Clayton
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Post by matti on Nov 26, 2013 9:07:28 GMT
Yeah I read about it in the newspaper DN. Understood that you are going to shoot it in Karlskoga.
/Matti
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Post by fredhocker on Nov 29, 2013 8:02:10 GMT
The gun was successfully removed from the mould yesterday, no voids or flaws, and the alloy matches the original very closely. We will spend a few days cutting off the gate and gunhead, cleaning up flash and mould dross, etc., then the gun will come to the museum next Wednesday for chasing and boring.
Fred
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Post by Clayton on Nov 30, 2013 16:32:04 GMT
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Post by fredhocker on Dec 11, 2013 8:20:22 GMT
The cannon is now at the museum, arrived Monday, and Tom Ward has been working on the exterior. We still have to build a 17th-century boring mill to bring the bore to the final diameter.
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Post by fredhocker on Oct 8, 2014 7:07:38 GMT
On Thursday last week, Oct 2, we successfully proofed the bronze 24-pounder copy, firing four rounds without incident. The largest charge, at 3.3 kg of powder, gave a breech pressure of 72 mPa (about 10400 psi) and a muzzle velocity of 399 m/sec (mach 1.17). The service charge we will use in the full trials starting next week will be 2.65 kg, which gives a muzzle velocity of 362 m/sec (mach 1.06). The proofing showed that at a low elevation of around 3 degrees, this is enough to throw a ball about 900 meters. It also showed that even if the ball leaves the gun at supersonic velocity, it quickly decays to high subsonic and then stays there, due to the exponential drag increase at transsonic velocities.
Fred
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Post by matti on Oct 8, 2014 8:01:56 GMT
You must have the coolest job possible!
/Matti
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Post by jules on Oct 8, 2014 9:17:26 GMT
Congratulations Fred! That's a great first result.
One question: you say that the speed of the cannonball quickly decays to a lower speed. That would be the speed at which the target will be hit then. Any idea how high that speed is?
Good luck next week!
Jules
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