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Old 04-08-2022, 09:01 AM
dugliss dugliss is offline
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Default Semroc SLS Aerodart launch on F22J?

Good morning all you BARs. I'm doing some pre launch research to see if I can launch my SLS Aerodart safely on F22J motors. This is the problem I'm having. I have been told that a safe stable launch requires a minimum Thrust to Weight ratio of 5:1. The ThrustCurve website which is very helpful matching motors to rockets tells me that although this motor will provide a T:W of 6:1, the lift off acceleration will be too slow meaning the rocket will be unstable. Thrust Curve puts this motor in the fail category for this rocket. Interestingly, I used ThrustCurve to find motors for the Aerodart in 2014 and then the F22J was in the "Motors that worked" category. I wonder why the result changed since 2014. Incidentally, the Aerodart will be launched on a 48" rod. Has anyone launched an SLS Aerodart on F22J successfully?
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Old 04-08-2022, 09:02 AM
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ghrocketman ghrocketman is offline
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I wouldn't do it.
The thrust profile of that motor sucks for anything but really light rockets.
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Old 04-08-2022, 09:29 AM
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tbzep tbzep is offline
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Quote:
Originally Posted by ghrocketman
I wouldn't do it.
The thrust profile of that motor sucks for anything but really light rockets.

Somebody call a doctor. GH must be really sick! Come on, man! You love power prangs!
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Old 04-08-2022, 12:10 PM
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ghrocketman ghrocketman is offline
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I don't like Powr-Prangs with any Mini-Max or Enerjet kits. That's just heathen blasphemy.
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When in doubt, WHACK the GAS and DITCH the brake !!!

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, if you have to ask what is "NORMAL" , you probably aren't !

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Old 04-09-2022, 09:55 AM
dugliss dugliss is offline
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I was only into LPR in the early 70s, so I didn't know anything about AP motors and the original Enerjet line, but C propellant looks good. My fav is White lightening, of course. SLS Aerodart launches great on F20W, but that's a SU motor. RMS is much more cost effective. E18W also works well for this rocket. Black Jack propellant is the reason for the slow launch issue here. Right now I don't have a mid power rocket in my fleet that I'm comfortable launching on F22J.
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Old 04-09-2022, 10:29 AM
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ghrocketman ghrocketman is offline
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I don't purchase BJ propellant anything for my 18, 24, 29 hobby, and 29 HPR RMS casings.
Not a fan of slow low thrust liftoffs. I prefer BLAST-Offs. FJ propellant is acceptable, but leaves a lot of residue.
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When in doubt, WHACK the GAS and DITCH the brake !!!

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, if you have to ask what is "NORMAL" , you probably aren't !

Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
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