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The XPRS launch allowed for
three days (Fri-Sat-Sun) of commercial motor launches and one day (Monday)
for experimental research motors. Unfortunately, the wind on Friday
was horrible. 25-30 mph winds were blowing most of the day. At
times the dust was creating "white out" conditions where it was hard
to see more than about 10-20 yards. At about 5:00 pm the wind subsided
enough to allow a few flights during the last hour before the waiver
closed at six.
Saturday was perfect!
No wind, sunny, clear and warm all day! It doesn't get any
better. The pads were very busy all day long. In the
morning, I successfully launched
Angelfire on an M1939 to over 15,000 feet. Angelfire carried my
GPS downlink system and I acquired good data during the entire flight. The
"3D" GPS flight trajectory is presented a bit further down on this page.
This was the 12th flight of Angelfire and it was recovered with no damage.
In the afternoon, I launched Starfire
on an M2200 Skidmark motor to just over 4000 feet. I sure love that
skidmark motor and this flight did not disappoint. All the details are
presented below. This was the 19th flight of Starfire and it too was
recovered with no damage. It landed only about 200 yards from the
flight line!
Unfortunately, the weather
on Sunday morning went back to what it was like on Friday. Strong
winds and blowing dust made it impossible to fly anything. Most
people immediately packed up at that point and headed home. I
hung around a little longer but left in the early afternoon and found it
necessary to "fly on instruments" to get to the exit point off the lake
bed. The dust was so thick that I was driving solely by GPS. I
used it to guide me the seven miles back to the highway.
It was an abbreviated
launch but at least we had one really excellent day.
Click on any photo on
this page to see a larger version of it. |
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Panorama of the XPRS
flight line |
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This view is looking
towards the flight line from the 500 foot pads at XPRS. It was taken
on Saturday, Sept. 15, 2007. Click on either link below to see
the FULL width of the flight line.
Click here to see a large high resolution image.
(1.1 MB jpeg file.)
Click here to see a smaller low resolution image.
(270 KB jpeg file.)
NOTE: Some web browsers will automatically fit this image to
match the width of your computer window. If yours does that, then be
sure to expand the image to full size. You should be able to pan
across the large image and get a good look at the whole flight line as if
you are standing at the 500 foot pads. |
| Shon Heiner helps me put Angelfire onto
the launch pad. |
| The altimeters are switched on after
Angelfire is in the vertical position. |
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Photo by Shon Heiner |
Photo by Vern Knowles |
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I (Vern) am standing next to
Angelfire just prior to launch on a 98mm
AeroTech
M1939 full M motor. Angelfire is 11 feet tall and 5.15 inches in
diameter. It weighed 52 lbs with the motor installed.
Angelfire turned in another perfect flight and reached 15,640 feet. The dual
deployment system deployed a drogue parachute at apogee and the main parachute at
1500 feet. It touched down 0.67 miles away. Angelfire has now
flown on the M1939 motor at the last three XPRS launches. Last year
it reached 15,576 feet and the year
before that 15,329 feet. All three are very very close. This
was the 12th flight of Angelfire.
Angelfire carried the usual assortment of electronics
gear on this flight. The drogue and main parachutes were deployed by
two
Missile Works RRC2 altimeters and an
ARTS
recording altimeter. The ARTS altimeter records the entire flight profile using
both a barometric sensor and an accelerometer. In the nosecone, a
high speed
Garmin
GPS unit was transmitting GPS fixes to the ground at the rate of five
readings per second using a
MaxStream 9XTend 1W spread spectrum frequency hopping 902-928 MHz
radio link. The data was received on the ground and saved into
a laptop PC running the
VisualGPS software. There was also a
Walston radio
transmitter at 216 MHz in the nosecone for backup location finding. The
data from the ARTS altimeter and the GPS trajectory are presented a little further down
this page.
View Angelfire construction
details here.
View photos of other
Angelfire
launches here.
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Photos by Vern Knowles |
Liftoff of Angelfire on an M1939 motor.
This is an animated set of
still images taken by a digital camera close to the launch pad. Each
image was captured at 1/8000 sec and the time between successive images is
200ms.
Click on the animation to
see the full set of 12 images and in a larger size.
Link to full size animation |
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Photo by Vern Knowles |
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Angelfire GPS Flight Trajectory |
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Angelfire carried a GPS
receiver and a special radio transmitter in the nosecone. The transmitter
sent GPS coordinates to a receiver on the ground. The data was recorded in
a laptop computer.
Click here
to see more details about the Angelfire GPS system.
After the flight, this data was
processed and then
loaded into the Google
Earth program to create a view of the "3D" trajectory.
The GPS trajectory was also
color coded for each phase of the flight by using timing information from the ARTS recording altimeter.
This view is looking to the
north east and from an elevation of about 14,000 feet above the playa at
the Black Rock dry lake bed. |
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You can view this
trajectory in simulated 3D by downloading the data file at the link below and
loading it into Google
Earth. You can then use all the standard pan, tilt and zoom
controls in Google
Earth to see it from any angle. (Google Earth is a FREE program
available here.)
If you already have Google
Earth installed, then you should be able to simply click on this link and
it will "fly you" to the Black Rock desert and display the Angelfire
trajectory. If that doesn't work, then right click on the link, save
the file to a convenient place and then open the file from within Google
Earth.
Link to Google Earth data file for Angelfire flight trajectory. |
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Altitude reported by GPS
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Velocity reported by GPS
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The charts above
show the altitude and velocity data reported by the GPS system. Each
point in the plot represents one GPS reading. This GPS unit updates at
five times per second. (Readings are spaced apart by 200ms.) The
peak altitude was 15,214 feet above the ground. The peak velocity
reported by the GPS was 723 mph. (The peak velocity reported by the ARTS
recording altimeter was 676 mph.) The descent rate on the drogue chute
started out at about 75mph and gradually decreased to about 62 mph as the
air density increased at lower altitudes. The descent rate on the
main chute was about 17 mph.
Click here to view Angelfire
GPS data plots in PDF format
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Angelfire Flight Trajectory Video |
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Six pages of analysis of
the data from the ARTS recording altimeter is presented below. You
can click on each page individually to see an image of it, or you can get
all six pages at once in a higher resolution PDF document.
Click here to view Angelfire Flight Data in PDF format
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Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
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Angelfire carries enough
electronics that it was possible to determine the peak altitude in five
different ways. The two MissileWorks altimeters
reported the peak altitude to be 15,540 and 16,151 feet. The ARTS
altimeter reported the peak altitude as 16,147 feet based on the
accelerometer and 15,149 feet based on the pressure sensor. And
lastly, the GPS reported the peak to be 15,214 feet. The average of these
five readings is 15,640 feet and the largest difference from the average
to any one reading is only 3.27%. That is very good agreement
among the five different sensors!
Maximum acceleration was
7.6 G's. Peak velocity was 992 ft/sec (676 mph). Angelfire
reached apogee in 31.2 seconds. After that, it descended on the drogue
chute for 2.33 minutes at -99.5 ft/sec and then fired the main chute
ejection charge at 1672 feet. It descended on the main chute at
-23.6 ft/sec for 62.5 seconds. Total flight time was
3.89 minutes.
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Starfire on a M2200 Skidmark
motor! |
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Photo by Shon Heiner |
Photo by Vern Knowles |
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Photo by Steve Jurvetson |
Starfire was launched late
Saturday afternoon on an
AMW M2200 Skidmark
motor . This motor generates a very loud "crackling" sound with lots of
black smoke and lots of titanium sparks flying everywhere.
This was the 19th
flight of Starfire. It reached 4,017 feet and landed about 200 yards
away. It was safely recovered with no damage. |
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Photo by Rick Clapp |
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Photos by Vern Knowles |
Starfire
Liftoff
This is an animated set of
still images taken by a digital camera close to the launch pad. Each
image was captured at 1/8000 sec and the time between successive images is
200ms.
Click on the animation to
see the full set of 9 images and in a larger size.
Link to full size animation |
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This is one frame from the
onboard camcorder. It shows a partial view of the flight line below.
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Photo by Vern Knowles |
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Starfire carried a digital
camcorder in the payload bay at the top of the booster. The camcorder is
a Sanyo HD1 Xacti. (model VPC-HD1) The beauty of this
particular camera is that it does not use tape. It records directly to an
SD memory card. This is much more tolerant of
acceleration and high vibration than a tape based camcorder. This
particular model can also record in HD video. (1280x720 pixels)
Click here to see the camcorder setup |
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The camcorder looks out
through a hole in the side of the booster coupler. The main body
tube slides over this coupler and has a mirror mounted that allows the
camcorder to look down the side of the rocket during launch. At
apogee the body tube separates from the booster allowing the camcorder to
look straight out to view the horizon and surrounding scenery as it
descends on chute.
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