Ye Olde Rocket Forum - View Single Post

Quote:

Originally Posted by Gus

Carl,

At WSMC last summer the Chinese were flying two step single stage motors. High initial thrust followed by slow sustain. They sounded like staged separate motors but were just single motors with two different steps to their burn. Very interesting sounding.

I presume they were using them in various events but I personally only witnessed them being used by the junior team in parachute duration (they flew in the lane next to Emma with the US juniors). The Chinese didn't do particularly well in that event but there was so much lift that day that it just didn't matter what motor you used. Realistically, the parachute and streamer duration models are so lightweight that you don't really need any increased thrust at liftoff. With pistons even an A1 will get up to stability speed by the time it leaves the piston.

I know these 10mm motors are just thought experiments at this point but our biggest disadvantage on the US Spacemodeling team is that we don't have 10mm motors to develop and practice with (at this point we don't even have a 13mm booster motor to practice with).

Our best altitude flight this year in S1b (B-altitude) was over 100 meters below the Slovenian winner. So we could REALLY use some American 10mm A 1.5s.

Steve

I remember a long 18mm D (4.5") that I pressed with four B charges with a 1-2 second delay between each charge. I had an external DECAP to provide the final delay and ejection charge. I placed a 1 oz charge of KCLO3 and aluminum dust as the "recovery device" and fired it at night in a thunderstorm. When the flash lit up the sky above the lower clouds, the sound took almost 5 seconds to reach the ground. I fired one earlier in the daytime and never heard the third and fourth charges and never saw it again.

We really want to be able to supply 10mm A1.5's to the USA team! In fact competirion is the primary reason for tooling for 10mm since it is not a "mainstream" engine.

I just finished reading the SR article on the WSMC. I would have loved to be there cheering Emma and the other youth. They all looked so happy and are all winners.