January 11, 2003
This was a 3 grain 38mm in a PML Callisto with altimeter and two stage
recovery. The rocket jumped off the pad quickly (see the analysis of the flight data below for a comparison to an Aerotech H-242 reload flown previously with this rocket)
and provided a nice flight to 2400 feet. The altimeter separated the rocket at apogee and the
main chute deployed at 400 feet with the rocket landing about 50 feet from the pad.
Most everyone present was impressed with the motor and noted that it sounded quite a
bit different than AP based motors. It produced a "smooth swish" vs. a "roar". The
flight nicely matched the Wrasp prediction and it appears that the thrust was the same
as the test stand data.
The rocket was recovered in excellent shape and the motor removed for examination. The
liner and o-rings were still in good shape and the motor had burned cleanly, leaving very
little residue in the casing.
I 358 KNO3/sorbitol
This was a 6 grain 38mm motor in a PML 1/4 Patriot with altimeter and two
The flight started with another perfect boost off the pad,
with the motor coming up to pressure very quickly again. The flight was to 2600 feet
and went well until the home-made igniter for the ejection charge decided that
it "wanted a little more time" from the homemade altimeter to light up. Unfortunately
the altimeter decided that went against it's programming and the result was a ballistic
trip back to the ground. At 400 feet (and about 200mph) the altimeter tried to make
amends by releasing the main chute and while this saved the rocket from a most certain
death, it did cost one fin and a zippered main chute compartment. It will fly again.
Click here for a 5MB video of the Patriot flight
Flight Data Analysis
As can be seen from the graphs below, the flight characteristics for these SP flights
are similar to the Aerotech Blue Thunder reloads. The acceleration graph is the red
line and altitude is shown in blue.
H-191 Sorbitol Motor in PML Callisto- click for bigger image
Comparison: H-242 Aerotech Blue Thunder in PML Callisto- click for bigger image
I-358 Sorbitol Motor in PML Patriot...OUCH! - click for bigger image
These were some pretty cool rocket flights! Most of the spectators had never seen a sugar propellant
in a motor before and were quite impressed with how nicely they performed. They mostly closely resembled
Aerotech "Blue Thunder" propellant in their performance, but the sound was quite unique.
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