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We are planning to use 24mm motors in the E and F class.  To get to the 750ft level we will use AeroTech re-loadable and single use motors.  We might use the longer delays to go past apogee if we can deploy our chutes using a mechanical means just before apogee.  If the rocket is over 390g (including motor) we will need an F motor.

Possible Motors

Motor	Type	Loaded Weight	Total Impulse *	Burn Time *	Rocket Weight   for 750ft	Cost	Comment
E18-4/7W	Reload	57	36.5	2.1	300-340g	$6	Only for light weight rockets
E20-4/7W	Single Use	49	35.0	1.6	300-360g	$8	Only for light weight rockets
E28-4/7T	Reload	55	39.7	1.2	320-380g	$6
E30-4/7T	Single Use	47	39.5	1.2	320-400g	$7	Best buy
F24-4/7W	Reload	62	47.3	2.1	400-460g	$7	May need to add weight
F39-9(6)T	Reload	59	49.7	1.3	420-480g	$7	May have too long of a delay
F32-4/6T	Single Use	64	56.9	1.7	460-520g	$10	Most expensive

* According to ThrustCurve.org

Here are the thrust charts from AeroTech.

Assembling an AeroTech reloadable is something we need to learn.  You need to follow the instructions closely. Making one error in the assembly will destroy your rocket.  One place where we differ is at the end.  We don't use the red cap to hold the igniter.  We use either a rubber band or masking tape.

Here is a YouTube demonstration of assembling a G motor.

Igniters

We have had some problems with the AeroTech Copperhead igniters - they crack when we put them in the motor and don't ignite.  We have to replace them at the launch rail, which adds risk to not being placed correctly and delays launching.  We tried the Quest Q2 G2 igniters but had a CATO on November 20, 2010.  The problem may have been the way we inserted the igniter - blocking the nozzle.  We tried a comparison test of the two igniters.  They work differently, but should not cause the CATO if inserted correctly.