[BProckets] end burning vs core burning

[Tom Mueller]

>>is there a major difference between end burning and
core burning as far as lift/thrust goes? Any other
differances such as sound or tail/smoke production?<<

There is a major difference between end burning and
core burning motors.  On an end burning rocket, the
amount of surface area of powder burning is only the
area of the end of the tube (A=pi*r^2 where r=radius
of the tube).  The amount of surface area of powder
burning in a core bruning motor is (A=Pi*r^2+Pi*r*s
where Pi=3.14159, r=radius, and s=slant height).  

Since the core burning motor has significantly more
surface area of powder burning it has significantly
more thrust (over a short period) assuming the nozzle
is the same on both motors.  A core burning motor will
typically only last a few seconds with lots of thrust,
however an end burning motor will burn for a much
longer interval, but have less thrust/lifting power.  

The core burning motor will generally have a lot more
"snort" noise than an end burning motor mainly because
of the major difference in the amount of powder
burning which produces much more gas that has to
escape.

Tom

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