What are the issues with spring firing cannons vs gas operated.i can't really be very specific that I'm not sure what questions to ask or if there ever used in any capacity.
Are you referring to a spring loaded piston that generates the gas pressure to propel the bb down the barrel?
All bb guns that I'm familiar with are pneumatic in nature. They use compressed gas to propel the bb down the barrel. The way the gas is compressed varies. The most common design uses a spring loaded pneumatic piston (Daisy Red Rider is an example). The second type is the "pump gun". These have a built in lever operated air compressor. The more pumps, the more power in the shot. The third type are CO2 powered bb guns. These use CO2 capsules, or for higher end target rifles, CO2 bottles (like paintball guns). The term spring gun is common in the Airsoft world. These work similar to the Daisy Red Rider in that a spring powered piston provides the gas pressure.
I've heard of a few people trying direct spring-propelled bbs for single-shot torpedoes in Big Gun format, but it has never worked out well. They were used on a few 1:144 scale motor torpedo boats generally between 6" and 9" LOA and only a few ounces displacement. Spring power seemed a good weight-saving solution, BUT 1) the builders had a very hard time finding strong enough springs to get a bb up to speed in just a few inches travel. 2) the firing mechanism was under tremendous stress, holding the springs compressed until in a proper attack position. 3) the recoil from firing was significant enough to capsize the model. Overall, it was not a successful endeavor. And unfortunately there are no technological improvements that can overcome the base issues. In every practical application, pneumatic systems are simpler, more effective, and more reliable.
I agree with Katori. I spent many hours on this and its not just what he said its also cocking the dam thing in a fragile boat. What I found is that I got better velocities with a steel rod striking the ball at the end of the barrel verses at the start of the barrel. Air is far more practical. The attached gun is 5" long and will penetrate 1/16" hull at one foot.
