I've recently been looking at artillery shells and some of them have raise a question for me. Were any shells designed for spin stabilization. I'm looking at shells and seeing what I'd say looks like it was mean to cause further stabilizing spin once the shell left the gun. But then I try to find out for certain if it's the shell and all I can find really is talk about the sabot and stabilization. So am I looking at pictures of the shells themselves or of the shells with the sabots in place.
The shells in question that have lead to this are the following:
I think you are pretty much correct Hellcat. According to the Timelife Echos of Glory series the James shells had a lead sabot: "When the shell was fired gases entered the projectiles base, passed through its ribs, and expanded a lead sabot into the barrel's rifling, which made the shell rotate." I doubt that the sabot was meant to separate after firing. If I remember right, I think the sabot looked like little fins that popped out of the ribs. However, the same book has a picture of a Schenkl Shell which apparently had a paper mache' sabot that burned up as the shell left the gun. Of course, this shell was particularly sensitive to water damage and thus not terribly useful, but it seems to be an interesting experiment to me.
Make sense, especially when you look at the shell links above. After all the flanges look slanted so they could certainly impart a corckscrew spin coming out of the rifled barrle. But then you have another Blakely shell with straight flanges (http://www.civilwarartillery.com/hap/page64.htm), looking at this one I have to wonder how the flanges are meant to guide through the grooves of a rifled barrel and cause rotation. This looks more like the grooves in the barrel should run straight and just be a grooved smoothbore rather than a smoothbore converted into a rifled barrel.
And then there's the definition of sabot on the site.
SABOT: The sabot served as the driving band for the projectile, and was made of wood, brass, copper, lead, papier-mâché, leather, rope, or wrought iron. The sabot for a rifled projectile was attached directly onto the projectile. When the weapon was fired, the gases from the propellant charge caused the sabot to expand into the rifling grooves. This, in turn, caused a rotation motion of the projectile which extended its range and improved stability. In the case of a smoothbore projectile a wooden sabot, made of poplar, basswood, linden, or other close grained wood, was used to hold the projectile with its fuze forward and in the center of the bore. Solid shot had the sabot attached with two crossed tin straps. If the wooden sabot was tied to a cartridge bag, the entire round was then referred to as fixed ammunition.
Ok, so the third and fourth sentences there basically say the sabot does the same thing as flanges. So why would the Pattison need both a sabot and flanges? Also, did the sabot fall away from the projectile then like it does today?