Texasgrape
Member
Hello; new to this forum so hope this is posted correctly; I have been in rocketry off/on for decades as a hobbyist with a few scale models under my belt but this is my first scale-scratch build; I am needing some input if anyone has the time:
I am scratch building a 1:32 Little Joe II QTV--I started on it 15+ years ago (back when Balsa machining still made custom nose cones and transitions; TG!) I have recently completed the no frills 'boilerplate' edition; I was wondering if someone could take a quick look-see to see if anything major wrong stands out; I am using OpenRocket--RockSim doesn't like LJ; it won't fly good in that program no matter what I do; so I went to OpenRocket which seems more accurate to me;
Although the stability margin is small (.64) the swing test was 100% successful loaded up and ready to fly; FYI: RockSim has the CP located 1 1/2" further aft than OpenRocket--have no idea which is correct;
Will be using Aerotech F44-4 motor; I simulated many but that motor just seems to bring in the best numbers for its first flight (to me anyway) I welcome input on anything; but other concerns are:
1 Will there be enough pressure to deploy the chutes? There is 6 3/4" of open parachute bay--even with the 10" stuffer tube;
2 After I glued in the stuffer tube/motor mount I realized the motor tube is not heavy walled but I reached in with a brush and beefed it up with 2 coats of slightly diluted wood glue
3 Engine choice?
I am using a 30" main nylon chute and a 12" nylon for the nose cone (command module and above); I am using the 12" as a pilot (semi-drogue) that I read George Gassaway used on his scale models: IDK seems like a good concept--those threads are old; perhaps there are new methods
Add'l info: The 1/4" dowel rod is a place holder for the tower and the siding will go on in the lower recessed portion of the main BT; all balsa has been sanded/filled/primed but I will leave the lower BT portion raw for the test flight; lastly adding 2 oz nose cone weight only changes CG about 1/8" forward so wasn't going to add any
Sorry for punctuation; period and comma bit the dust on my macbook! I've attached some pics of the stats and simulation as well as a couple pics of the build--can link to the swing test if anyone interested--
Thank you to those who keep this forum alive--so many helpful and knowledgeable people!
Dana
I am scratch building a 1:32 Little Joe II QTV--I started on it 15+ years ago (back when Balsa machining still made custom nose cones and transitions; TG!) I have recently completed the no frills 'boilerplate' edition; I was wondering if someone could take a quick look-see to see if anything major wrong stands out; I am using OpenRocket--RockSim doesn't like LJ; it won't fly good in that program no matter what I do; so I went to OpenRocket which seems more accurate to me;
Although the stability margin is small (.64) the swing test was 100% successful loaded up and ready to fly; FYI: RockSim has the CP located 1 1/2" further aft than OpenRocket--have no idea which is correct;
Will be using Aerotech F44-4 motor; I simulated many but that motor just seems to bring in the best numbers for its first flight (to me anyway) I welcome input on anything; but other concerns are:
1 Will there be enough pressure to deploy the chutes? There is 6 3/4" of open parachute bay--even with the 10" stuffer tube;
2 After I glued in the stuffer tube/motor mount I realized the motor tube is not heavy walled but I reached in with a brush and beefed it up with 2 coats of slightly diluted wood glue
3 Engine choice?
I am using a 30" main nylon chute and a 12" nylon for the nose cone (command module and above); I am using the 12" as a pilot (semi-drogue) that I read George Gassaway used on his scale models: IDK seems like a good concept--those threads are old; perhaps there are new methods
Add'l info: The 1/4" dowel rod is a place holder for the tower and the siding will go on in the lower recessed portion of the main BT; all balsa has been sanded/filled/primed but I will leave the lower BT portion raw for the test flight; lastly adding 2 oz nose cone weight only changes CG about 1/8" forward so wasn't going to add any
Sorry for punctuation; period and comma bit the dust on my macbook! I've attached some pics of the stats and simulation as well as a couple pics of the build--can link to the swing test if anyone interested--
Thank you to those who keep this forum alive--so many helpful and knowledgeable people!
Dana
Attachments
Last edited: