Booster Video  -  pending recovery

Slow Motion Tower Video with ground tracking - WMV  MOV 

Full speed Tower Video with ground tracking - MOV

Motor: Aerotech M1315

Goals

• Level 3 certification flight
• Apply any tweaks needed based on the results from flight 2d

Technical details

• The Tower will release the capsule, allowing it to proceed with the free fall.
• G-Wiz avionics for deploying the recovery system after the free fall.
• Capsule Kira 7's fourth flight
• DVII video/audio capture cockpit camera

Results

• Rocket became unstable shortly after launch and impacted the playa, tower first at a substantial speed.
• all major components of the airframe were destroyed
• Tower video broadcasted up to point of impact
• All avionics were destroyed
• All on-board cameras were destroyed
• There is a slight chance the memory card can be salvaged for the booster
• Very remote chance the memory card can be salvaged for the capsule
• Astronaut was seriously damaged (but we might rebuild him) and his flight suit shredded.
•  All parachutes were undamaged with only a minor tear in the 12' main
• The tower video transmitter seems to be in working condition (freaking miracle)
• The M-1315 motor casing was undamaged (good thing as it was a loaner)     

What made this flight so unstable?

RockSim has trouble with stability formulas on rockets that have transitions to smaller upper airframe diameters.  It currently is hard coded to use the leading diameter found in the rocket's design. (a future version will allow the designer to change that value)  

For Mercury Joe, RockSim used  the tower antenna diameter of .5 inches for the airframe diameter and thus reported the Static Margin (caliber of stability) was 23.18.   Boy  was that wrong and the answer was staring me right in the face but because my lack of experience with this aspect of RockSim,  I missed it.  I simply read the analysis (over stable) and trusted that.

For those of you (like me) who might not know,  RockSim's Static Margin is the same as the "rule of thumb" formula that produces what most seem to call Caliber of Stability (or Margin of Stability). 

Anyway -  In the sim file, replaced the entire upper section (capsule to tower) with a single conical nose cone that spans the same distance in length and the Rocket's Barrowman result is now marginally stable with the K and L motors and unstable with the M.  This matches my flight results. Obviously I lucked out with the marginally stable results it helps explain some flight characteristics we saw near apogee with the K powered flights where the rocket ever so slightly fish tailed.

As I do the rebuild,  at least now I'm comfortable with how to get trustworthy design feedback.