What were LSA "sets" used for regarding 61.319 and 61.323?

[AviatorCrafty]

These regs don't exist anymore and are reserved in subpart J but I was always curious about what they were for. I did some research and turns out back then it seemed when you were issued a sport pilot license you were endorsed for a "set", what were these exactly? I found a video from Paul Hamilton dated from 2010 detailing LSA reg changes and he mentioned they were being removed and being replaced with the below/above 87 knots VH endorsement so you could fly any LSA as long they fit into what you were endorsed for with regards to VH. I'm curious why they initially did it with these "sets" but then changed it to the above/below VH system.

[3Dreaming]

From 61.1 a set of aircraft is defined as, "Set of aircraft means aircraft that share similar performance characteristics, such as similar airspeed and altitude operating envelopes, similar handling characteristics, and the same number and type of propulsion systems." Prior to 2010 there was only a speed endorsement for a Vh greater that 87kt not less. Light sport aircraft covered a pretty wide envelope of aircraft from an open wire braced 2 seat Quick Silver to the modern light aircraft coming out of Europe. If you trained at one end of the spectrum you were not necessarily prepared to fly at the other even though you were a certificated sport pilot. The sets were kind of confusing, so the FAA changed to the greater than less than 87 kts that we have now.

[comperini]

Back then, there were 8 sets for airplane. 4 “slow” ones and 4 “fast” ones. Land, sea, etc.

Here is the diagram: https://flysportusa.com/lsa2.php