Author Topic: SECOND Annual N.R.V. Mortar and Cannon Shoot  (Read 7128 times)

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Offline Cat Whisperer

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Re: SECOND Annual N.R.V. Mortar and Cannon Shoot
« Reply #90 on: October 06, 2008, 03:58:43 PM »
...
Looks like a great time was had by all, wish I could've been there.

It was indeed a great time.  M&T set the pace by bringing there high quality precision 7" Brooke.  Dom loaned Wayne a GB mortar and pointed him in our direction!  (Wayne is fighting getting logged in to the board in a way that the gremlin's of the board will let him post; and is recovering from wisdom teeth surgery.)

Terry, there will be more times like this.  Some here, some there.  We'll meet in person some time and share a few black powder rounds.

Tim K                 www.GBOCANNONS.COM
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U.S.Army Retired
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Offline Double D

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Re: SECOND Annual N.R.V. Mortar and Cannon Shoot
« Reply #91 on: October 06, 2008, 04:32:42 PM »
So if the muzzle is raised above the level center line and the breech is lowered below the level centerline, does the muzzle dip
when fired.     Yes, it does.


Interesting!

I would have thought this would have occurred

Quote
When it's pointed downward such as you had to do I would expect the muzzle to dip.     Why?

I hope I can explain this so it makes senses.  

When the barrel is level, the force vectors of gravity are ninety degrees to the center line of the barrel.  The vector of force of preponderance is also 90 degrees.  If the barrel centerline is depressed say 10 degrees, the vector of gravity is now 80 degrees to the centerline. Because the vector of preponderance is rotating around the trunnions it still remains 90 degrees but the preponderance is reduced due to the change in the vector of gravity.  The preponderance on the trunnions will increase.  The negative preponderance on the muzzle will decrease.

With the muzzle/bore level recoil forces would be straight to the rear along the bore centerline and against the trunnions.  The recoil forces push weight of the carriage rear ward.  In the case of a depressed barrel recoil forces would be slightly upward.  This would tend to lift the carriage rearward.  The weight of the carriage would resist the lifting effect.  Further the length of the carriage would work like a lever, the fulcrum being the rear of the carriage.  Since every action has an equal and opposite reaction the energy would be transmitted back to the muzzle whipping it down.  This whipping down would be increased by the decreased negative preponderance of the muzzle, not only from it's actually mass, but it's length--longer lever.

Sounds good anyway.

Oh, and preponderance is now spelled correctly.



   

Offline seacoastartillery

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Re: SECOND Annual N.R.V. Mortar and Cannon Shoot
« Reply #92 on: October 06, 2008, 05:15:28 PM »



With the muzzle/bore level recoil forces would be straight to the rear along the bore centerline and against the trunnions.  The recoil forces push weight of the carriage rear ward.  In the case of a depressed barrel recoil forces would be slightly upward.  This would tend to lift the carriage rearward.  The weight of the carriage would resist the lifting effect.  Further the length of the carriage would work like a lever, the fulcrum being the rear of the carriage.  Since every action has an equal and opposite reaction the energy would be transmitted back to the muzzle whipping it down.  This whipping down would be increased by the decreased negative preponderance of the muzzle, not only from it's actually mass, but it's length--longer lever.

     Douglas,   I think you have found the essence of our muzzle dipping tendency in your section which I highlighted in purple. I also enjoy hearing Mike's favorite theory as well.  He insists that the tube rotates very slightly in the trunnion cradle and compresses everything under the point where the cascabel meets the elevation screw, meaning the screw, itself, the capstan wheel parts, the very robust transom, the cheeks, and finally the 16 X 18 inch rail beams too.  The rebound, caused by compression release of kinetic energy causes the breech to move upward and the resulting muzzle dip. 

Regards,

Tracy and Mike
Smokin' my pipe on the mountings, sniffin' the mornin'-cool,
I walks in my old brown gaiters along o' my old brown mule,
With seventy gunners be'ind me, an' never a beggar forgets
It's only the pick of the Army that handles the dear little pets - 'Tss! 'Tss!

From the poem  Screw-Guns  by Rudyard Kipling

Offline Double D

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Re: SECOND Annual N.R.V. Mortar and Cannon Shoot
« Reply #93 on: October 06, 2008, 06:14:17 PM »
Add what Mike says to what I said and you have it... That Mike is one smart guy!

I got the idea some years ago watching a slo-mo of a Parrot Rifle firing, everything flexed.  The wheels came off the ground and the trail dug in and you could see it flex. When the wheels slmmed back to the ground the axle flexed and the barrel snapped down.  The carriage jumped up and rolled back.  Incredible the forces at play. 

Remember that cannon with the broken trail that someone posted a few months back!


Offline Ex 49'er

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Re: SECOND Annual N.R.V. Mortar and Cannon Shoot
« Reply #94 on: October 06, 2008, 08:18:04 PM »
When you're walking on eggs; don't hop!!

Offline leesecw

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Re: SECOND Annual N.R.V. Mortar and Cannon Shoot
« Reply #95 on: October 07, 2008, 04:24:30 AM »
Regarding the Blakely that broke at Grayling in 2007. Those guys were back at Grayling with it this year with a steel axle. Not the same accuracy as Stuart's troopers back then carriage wise but who wants crushed tippy toes in the name of  historical accuracy.  Put another round in and keep em shootin!
If Guns cause crime, then mine are defective...Ted Nugent

Offline guardsgunner

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Re: SECOND Annual N.R.V. Mortar and Cannon Shoot
« Reply #96 on: October 07, 2008, 09:33:24 AM »
The carriage that they put the Blakely on is copied after a original Whitworth carriage the the Horse Soldier shop in Gettysburg just sold. Out of the norm ,but correct.