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OregonRocketry
held its annual Desert Heat launch on July 21-23, 2006 at their launch
site 2.5 miles southwest of
Brothers Oregon. "Desert Heat" is right, man was it
hot! |
This launch certainly lived up to its name.
Temperatures were above 100 all three days. Despite that, it was
still a heck of a lot of fun. I only flew two rockets at this launch
but both were on M-motors and both were successful and very satisfying
flights for me.
On Saturday I launched Starfire
on an AMW M3000
"Super Tiger" motor along with a full complement of six out-board J-motors
that were programmed to air-start in two sequential sets. A first set of
four J350's would ignite at 5 seconds and then a second set of two J570's
would ignite at 8 seconds. This is exactly the same configuration I
attempted at FITS 2006 earlier this year.
At that launch the air-starts never lit, but this time everything worked
exactly right. (I believe I know why and I'll explain all that
further down on this page.) The total motor impulse for
this flight was 12,290 NS which is in the "N" class and it pushed Starfire
to 9,812 feet. This was the 14th flight of Starfire and the highest one so
far. On this flight Starfire was carrying a brand new digital
video camcorder in the lower payload bay. Unfortunately, I didn't
get any on-board video from it. I thought I had completely erased
the memory card in that camera prior to launch, but I must have been
thinking about a different camera. The card was full and there was
no flight video. Dang it! However, Starfire also carried
two digital still cameras in the upper payload bay and some photos from
those cameras are presented below.
On Sunday I successfully launched
Wildfire on an
Aerotech M1315
motor to 8,020 feet. Wildfire carried an upgraded version of my
video TV transmitter that sends back
live video during the flight. The transmitter was recently upgraded
with a new video camera to fix the problem that occurred at the
FITS 2006 launch where the video was only in
black and white. The on-board video from this flight is
presented further down on this page. This was the 20th flight of
Wildfire!
I want to thank all those that helped make
these flights happen. Jim Purcell and Steve Cutonilli helped me put
Starfire on the launch pad. Steve also did all the TV signal
tracking antenna pointing during the Wildfire flight. Jim Purcell,
Eric Montbriand and JP Roberts helped put Wildfire on the launch pad.
I also got great help from Larry Taylor, Vanessa Purcell and Chris Beekman
to video tape these flights. Thank you all! It is a real
pleasure having so many folks willing to help out.
I would also like to thank Greg Clark and JP Roberts for all their hard
work running the launch as well as all the rest of the OROC members that
helped to make this launch such a success. Nice job everyone!
Let's do it again next year! Hopefully it will be cooler, but
somehow I doubt it. |
| Click on any photo on
this page to see a larger version of it. |
Photo by Vern Knowles
This view of the Brothers
launch site is looking north and at the back side of the flight line from the hill
used for the away cell. It was taken on Saturday. The standard high power pads are out beyond the other side of the flight
line.
Click here to see a large high resolution
version of this panorama.
(1.5 MB file.)
Click here to see a smaller low resolution
version of this panorama.
(220 KB file.)
NOTE: Most web browsers will automatically scale these
panorama images to fit the width of your computer window. If yours
does that, then be sure to expand the images to full size. You should
be able to pan across the large images and get a good look at the whole
flight line. |
|
Photo by Vern Knowles |
The M3000 main motor is already
in place so now it is time to install the six out-boards that will be
air-started. Four J350 motors lay waiting on the right side of the
blanket and two J570's on the left side. |
|
Photo by Vern Knowles |
All six out-boards are now
in place and the igniters are installed. The igniters are held in place
at the top of each motor core using a stiff length of piano wire. The
piano wires are bent at a right angle as they exit the motor nozzles in
order to brace them against the motor retainer plate that will be
installed next. |
|
Photo by Vern Knowles |
An aluminum retainer plate
retains all of the out-board motors. After the plate is secured in
place, some modeling clay was used to help seal up all the cracks and
crevices between each motor. Clay was also added over the igniter
wires themselves to help protect them. This helps protect the
air-start igniters from each other as the motors ignite at different
times. |
|
Photo by Vern Knowles |
The holes in the retainer
plate were also sealed up with aluminum foil tape to protect the igniter
wires from heat and "splash back" from the main motor exhaust hitting the
blast deflector on the launch pad. When the air-starts ignite,
they will of course blast right through the aluminum foil tape. |
|
Photo by Vern Knowles |
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Liftoff on the AMW M3000 "Super
Tiger" motor! |
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PLEASE NOTE: To
view this video it is probably best to right-click on the link and then select "Save Target As ..." so that it will store the movie file on
your computer. You can then open the file and view it after it is
completely downloaded. Doing so will allow it to play cleanly and
continuously without all the starts and stops caused by internet traffic. |
|
Photo by Tsolo T.
Tsolo from RocketShots! © 2006 |
Photo by Tsolo T.
Tsolo from RocketShots! © 2006
Starfire descending on two parachutes.
Click on the photo above and you will be able to see the
digital still camera module hanging
far below the parachute on the left side. Photos from that camera module
are presented below.
At left, Starfire climbs higher as the central
main motor is nearing the end of its burn. After a short coasting
interval the first set of four J350 air-starts ignited right on schedule
at five seconds into the flight. After those burned out, the last
set of two J570 motors ignited and boosted Starfire on up to a peak
altitude of 9,812 feet. |
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This was the third flight
of Starfire with all six out-board air-start motors installed in the
booster and the first flight where all six were successfully lit. On
many past flights, even with fewer air-start motors installed, the
MissileWorks PET2
timer responsible for igniting the motors was mysteriously getting reset
mid flight. When that happens it enters a "safe mode" and does not ignite
the air-starts. It took a long time to figure out what was causing
this problem. Timers, batteries and wiring harnesses were all
individually replaced from one flight to the next and ultimately to no
avail. Sometimes the reset problem did not occur, so it would appear that
the most recent change had fixed it, only to have it return again on a
subsequent flight. The problem could not be duplicated during any
ground testing. It was very intermittent and a complete mystery
until Bob Yanecek came up with the answer.
Bob identified that the
problem related to the break wire being used to start the timer at
liftoff. A small thin wire from the timer was routed out the bottom
of the booster so that it could be tied to the pad. When Starfire
lifted off, it would break the wire and the timer would start counting
down to fire the air-start igniters. In theory this works fine but
the trailing break wire is also prone to picking up electrostatic
discharge (ESD) from the hot ionized gas in the motor exhaust.
One timer even came back on a previous flight with permanent ESD damage to
the microcontroller break wire pins. That should have been a big
clue right there!
The solution was to
eliminate the trailing break wire. In fact, I have gone away from a
break wire system all together and now use a connector that gets pulled
apart at liftoff. The connector is inside the electronics bay at the
forward end of the booster section. Consequently, no more
potential for the timer to get zapped with ESD. Another option would
be to use the G-switch on the timer, but I personally wanted to avoid
doing that since it is much harder to verify the G-switch is working
properly prior to flight. I also want to avoid any possibility the
G-switch might fail to detect liftoff but instead detect touchdown and
ignite the motors after landing. In the end, each approach has it's
pro's and con's but I prefer the pull-pin method and now I think it is
finally working properly. |
|
Photo by Vern Knowles |
Photo by Vern Knowles
The nearby town of Brothers Oregon as seen by
a camera onboard Starfire. Click on the photo to get a better look at it. |
|
Photo by Vern Knowles
Starfire is suspended high above the desert
floor by two parachutes. The flight line is in view in the lower
right corner of this photo. This photo was taken by an onboard
digital still camera that was itself suspended below one of the
parachutes. Information on the
camera module can be found here. |
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Wildfire was launched on Sunday at
Desert Heat using an
Aerotech M1315.
It was carrying an upgraded version of my
video TV transmitter that sends back
live video during the flight. It was recently upgraded because
the video camera had failed at the FITS launch
earlier in the year and was only producing a black and white image.
That camera was replaced with a newer one and the color is back. The
new camera is also higher resolution so the image is better than it was
before. The GPS unit in Wildfire was also replaced with a newer one to see
if it would work any better. The onboard GPS provides data that is
overlaid on the video image transmitted back to the ground. The
problem is that the GPS has trouble locking up to the satellites in the
presence of the strong TV transmitter signal that is very close to the GPS
frequency. The new GPS unit was locking up okay prior to liftoff,
but unfortunately it lost lock right at liftoff and never re-acquired
prior to touch down. Of course the
Walston transmitter onboard was
still pinging away, so it was no trouble to find and recover the TV
transmitter module even without the GPS information.
This was the 20th flight of
Wildfire and aside from the GPS unit losing lock, the rest of the flight
went flawlessly. Wildfire reached 8,020 feet. The airframe was
recovered 0.63 miles west of the launch pad. The TV transmitter
module was deployed on a separate parachute and was recovered 0.39 miles
southwest from the pad. There was no damage to either one.
Since Wildfire was launched
from the "away cell" on the hill, I was not able to manage the TV receiver
and tracking antenna back at camp. However, Steve Cutonilli was kind
enough to do all that for me during the flight. Thanks Steve! |
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This is the onboard video that was transmitted
back to the ground during the flight. The image is overlaid with
textual information from the GPS. Unfortunately, the GPS lost lock
right at liftoff so the displayed information was frozen during the
flight. By the way, the indicated altitude is in meters above sea level
and the time is GMT. The KD7KYL is my HAM call sign.
View
higher resolution
MPEG2 version
(35 MB)
View low res Windows
Media Player version
(10.8 MB)
|
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PLEASE NOTE: To
view these videos it is probably best to right-click on the link and then select "Save Target As ..." so that it will store the movie file on
your computer. You can then open the file and view it after it is
completely downloaded. Doing so will allow it to play cleanly and
continuously without all the starts and stops caused by internet traffic. |
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