h a l f b a k e r yBunned. James Bunned.
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Level Flight Bullet
Counter spinning cylinders on either side impart stability without spinning entire bullet | |
To eliminate the spinning of a rifling stabilized projectile
so that electronic devices such as cameras may have a
more effective platform to operate from.
The bullet is slightly ovoid shooting out of a barrel of the
same shape. The rifling is cut into the left and right side
of
the barrel
in a contra-rotating configuration. The bullet
has
two rotating cylindrical portions on either side along the
bullet's long axis that spin in the directions that their
respective rifling turns them therefore spinning them in
opposite directions to each other. Thus the bullet flies
flat
and stable with the two spinning masses counteracting
each other while imparting stability to the unit as a
whole.
So basically you use specialized rifling and
projectile/muzzle shape to create two contra-rotating
gyroscopes to keep your projectile stable rather than
spinning the whole thing in one direction.
Brunswick rifle
https://en.wikipedi...iki/Brunswick_rifle Lovely little thing ... actually, a carbine. [8th of 7, Jun 04 2016]
or get smarter bullets
Bulls_20Eye_20Bullets [theircompetitor, Jun 04 2016]
[link]
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This is just a twist (ha, ha) on the idea behind the Brunswick rifle. |
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I don't think I described this well. The new design is
for a 3 part bullet, a body that holds two articulated
rotating cylinders, each rotating in opposite
directions to each other. |
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A picture will really clarify this but maybe tomorrow.
Busy as heck today. |
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We thought about Glock polygonal rifling. A trilobal design with twists in opposite directions for each portion of the projectile would spin each section in opposite directions. |
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The problems would be (1) getting the two segments to separately engage "their" bit of the rifling, and (2) projectile obturation (gas seal). |
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Something like a plaswad base on each section might do it. |
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It's still going to be very, very hard to make a couple of bearings that are effectively frictionless at high RPM and temperatures, and that withstand the shock. |
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No need for the bearings to be frictionless, they
just
need to not significantly retard the turning of the
gyroscopic elements for the duration of the flight. |
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//The problems would be (1) getting the two
segments to separately engage "their" bit of the
rifling,// |
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Which is solved by having them on two separate
axes nestling them side by side. The rifling also is
located in two different positions on the barrel,
the left and the right. |
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This really needs a drawing. Tomorrow maybe. |
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So, if I understand this idea, you want a bullet
with two rollers, one on each side, whose spin
stabilises the bullet while the body of the bullet
does not spin? |
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I think the first problem is that, even if the rollers
and their bearings survive the firing, they will not
be friction-free. Given the high speed of their
rotation, any friction will be a problem. |
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Moreover, if the friction of one bearing is even
slightly different from that on the other, there will
be a net torque on the bullet. This torque will be
about an axis which is not coaxial with the bullet
itself, and hence the bullet will tend to corkscrew. |
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//a bullet with two rollers, one on each side,
whose spin stabilises the bullet while the body of
the bullet does not spin// |
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//if the friction of one bearing is even slightly
different from that on the other, This torque will
be about an axis which is not
coaxial with the bullet itself, and hence the bullet
will tend to corkscrew.// |
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Hmm Good point, you're absolutely right. Any
variance in rotation between the two cylinders is
going to cause the projectile to roll. |
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Have them contact each other via a gear so they're
both rolling at the same speed. |
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I"m just curious, how many RPMs to you really
need to stabilize a bullet? The little toy gyroscopes
I had as a kid kept upright just fine and I know it
was spinning a heck of a lot slower than the
180,000 RPM of a bullet. So if it were necessary to
impart a slower spin to the cylinders due to issues
of friction it seems like you'd have some leeway
there. |
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I also just though of another way to do this, you
could have... |
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let me put up another idea. |
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I guarantee this will not work even a little bit, and the
bullet will be just as unstable as it would be without the
two cylinders spinning (barring some unexpected
stabilization from the Magnus effect or something). Any two
equal-in-magnitude-(the site tells me I need to put a space
here)-moment-of-inertia counter-rotating
rotors will cancel out each other's momenta of inertia,
leaving you with no stabilization. (I know because I have
looked into this before, for CMGs.) |
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