Flight 2E (crash) report
Enough with the crashing
Video - pending recovery
Video with ground tracking - WMV
speed Tower Video with ground tracking - MOV
|Astronaut: Buzz Aldrin
Motor: Aerotech M1315
- Level 3 certification flight
- Apply any tweaks needed based on the
results from flight 2d
- 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
- Rocket became unstable
shortly after launch and impacted the playa, tower first at a
- all major components of
the airframe were destroyed
- Tower video broadcasted
up to point of impact
- All avionics were
- All on-board cameras
- 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)
made this flight so unstable?
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)
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
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.