Originally Posted by vulcanitebill

This is my memory of it as well. Most of my early flying was about 1965-1969. I built a Ranger back then and launched it with both series I and series II B's. Those were the thick walled engines and a B filled the available space, no room for enough propellant for a C with delay and ejection charge.

I remember when the Big Bertha came out, one of my friends built one. It did have the low and slow majestic flight characteristic, and I wasn't interested in it for that reason. Plus it wasn't very sleek with the blunt nosecone. Nowadays a BB would fly very well on a modern C engine. I'm actually planning to build a BT60 rocket, maybe a Vagabond, to use for D12 motors.

We built models with the BT10 and BT30 tubes in those days. I had forgotten about the BT40 tube but I still have one model made with it, the BT40 is not much bigger than the BT20 motor mount tube. I remember when the BT55 tube came out and I built a scratch built design with it. I thought this was a good tube for a B, slightly faster than a BB.

Estes didn't have C single stage engines back then but at some point in time we discovered FSI engines and they had a C. It was bigger than 18mm, maybe 20mm or 21mm. I tore the motor mount out of my BT55 model and made a motor mount just to fit the FSI engines. Now that I think about it it might have used the BT40 to hold the motor.

As a kid we had made our own launch system using dry cell batteries, so we could carry it out into my grandfather's pasture. When I launched my Ranger we had someone drive us to a different launch site and we used their car battery for power. This is another advantage of a single motor over a cluster.