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Well-Known Member
Dec 30, 2003
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just started on a SAM-X 2 stager

the booster stage called for a 18 mm motor.
but i'm going to use a 24 mm motor .

but keep the upper stage a 18 mm motor

heres the 1st pic
This is a cool rocket that is rather rewarding to display when done well.

I don't have pictures of mine - I should fix that.

Anyway - the altitude given on the insert card of the kit is a bit exaggerated, but not by much. This thing outperforms an Estes Hercules on a C6-0 / C6-7 stack. Trust me, that's **** high for a sustainer that size!

Anyway - you'll probably want to increase the nose weight for that D engine. I'll cruise over to EMRR and check out the RSim file and post back here when I confirm this. But getting back to it's screaming high altitude on C's, I just have one thing to say about upsizing that booster: Good luck getting it back!

According to the RSim file on EMRR - modifying it by removing the 18mm engine tube and block from the booster and making it a 24mm booster - you have to double the nose weight to maintain stability in the 2 stage configuration. This greatly offsets the OOMPH delivered by the larger D booster, and only about 150 ft in altitude gain is realized (I'm suprised by this....)

Anyway, with that said, If all that is gained is 150 ft I'd stick with the 2 x 18mm configuration in the kit. That way, you don't have to add additional nose weight and you'll have a better performing rocket if flown as a single stage rocket without the booster. Plus, C's are cheaper than D's.

Have fun!
please let me know what you find out with RSIM.

i got it free so if i lose it ooowell.
but thats all the fun about up grading the motors.
if they come back then its a good day.

besides my mom sent me 4 packs of D-12-0 i need to use up.

i think i write to slow :D
Fore Check thanks for the info

but i still think im going to go with the 24 mm booster