Sweet!
At uni we had this so-called Super Senior, that is, he had been there 7 years and, back then, was still w/o his BS. (Very bright… but unfocussed and easily distracted.) Being serious about his model rocketry hobby, he experimented with ways to space his Estes stages as far apart as possible and still have one engine ignite the one above it, and that, eventually, by having one engine ‘talk’ to the other via a metal tube. He tried different tube lengths, outer diameters, wall thicknesses, and materials. (This was all pre-Taguchi, so his experiments were not the most efficient or cost effective.) I don’t recall what optimal tubing he ended up with, but his experiments go written up in a NASA report! Pretty good for any student, much less a Super Senior.
