Posted 15 January 2013 - 05:36
As for rate of fire, it techically should almost be like fuel- set by the pilot. The Vickers, Spandau, Lewis, and Parabellum all had a spring tension settings on the side to set the rate of fire. Set it up fast, and you use up ammo faster and risk more frequent jamming. Set it too slow, and it fires more reliably but may not be as effective when the enemy falls under them. Again, being a pilot controlled setting would be nice.
But, also a tid bit, my buddy, who is a renowned Spandau expert (anyone who has gone to the Dawn Patrol in Ohio has most likely seen him and his D7 prject and layout of Spandaus you can touch and feel), told me that the Germans used a standard setting for rate of fire at 420rpm I believe. That seemed to give the best overall result, and they made it a standard setting for the field instructions. I imagine some pilot may have deviated, but it's a good reference to get the feel for what worked well for the guns. the Lewis was typically set to 700rpm by most pilots, and I'm not sure on the Vickers, although he did confirm that they had a later version that ran at 800rpm, which would imply that earlier versions were run at a slower rate- I would venture to guess around 400, similar to the Spandau, as they were both derived from the original Maxim design.
Having had the pleasure of firing the Spandau,we found that the cotton belts were probably the weakest link for jamming. I imagine ammo was a problem back then too, but we had modern ammo made of today's quality and it all fired fine (you can't find 7.92, so the barrle was bored to fit 8mm rounds). We set the gun at a few rates, and found that a bit over 300 rpm worked best, but then, age probably was an issue for the big return sping, that sets the recoil rate, and thus the rate of fire, and mechanisms.
We were using brand new reproduction belts,and when the gun did jam, it was usually from biting the cotton belt. It bit the belt because the belt was not sewn perfectly on the edges. Boy does that make a big impact. What may look like a slight deviation of path in the seam will almost surly cause a jam. The belt gets caught in the mechanism, and I can totally see why they needed a hammer to unjam it. We had to pull on the cocking lever really hard to free the belt, and, yes, we used a mallet to help sometimes. And that was with the gun out in the open. I imagine in a seated position behind the gun, where one can't get good leverage was what made jams so painful to the pilots.
When the metal link belts came to be, the quality of fire had to greatly improve and jams were probably far less frequent over the cotton belts. To me, the gun was designed too perfectly and needed a precision belt to carry the bullets, but a cotton belt can't really be made consistantly to a high level of precision to be trusted every time. I envision the better pilots probably having personal gun belts they used over and over, once they got one that worked well for them.