Pro38 Q

if anyone has ever noticed the Pro38 motors have alot of erosion. the G69s I have fired have alot and I figured they did because the nozzle seemed so inneffieciant and small.

However this weekend after I fired the I285 I wonder what the nozzles are made out of. I looked into the nozzle and noticed the thoat seemed to be made of something different than the divergance section. This is because the thoat had not erosion but then the divergance section had tons. The smallest point of the divergance section had actually grown in size.

Does anyoine know why this is?

--Ryan

The nozzle is embeded with graphite. The graphite does not change much, so it keeps the chamber pressure high... so you don't drop like Redline Errosion with Aerotech motors (See the thrust curve for an I366)... Still very inefficient because a good nozzle expansion of about 15 degrees yeilds about 20% performance increase of thrust, but these surfaces are eroded away.