As usual Friday was the research launch day for flying custom motors designed and built by individuals.  Saturday and Sunday were the launch days devoted to flying commercial motors.

Photo by Tsolo T. Tsolo from RocketShots! © 2008

As you can see, we had great weather for flying rockets!  I arrived mid Friday afternoon and spent the rest of the day getting setup.  My plan was to fly three rockets at this launch.  Angelfire would go Saturday morning on an Aerotech M1419 motor with an expected altitude of 10,500 feet.  The photo above shows me with Angelfire just before launch.  I was particularly looking forward to this flight because it would be my 50th M-motor flight!   It was definitely a real thrill when it all went well. Even after 50 M-motor flights they are still a lot of fun for me.

On Saturday afternoon I planned to fly Wildfire with an onboard HD video camera using an AMW L1080 "Blue Baboon" motor  to about 4000 feet.  That flight would be Wildfire's 25th successful flight so it too represented a major milestone.   And finally, on Sunday morning the plan was to fly Coldfire on a HyperTek K240 hybrid motor to about 4000 feet.  Coldfire is relatively new and this would be only its 4th flight.

All of the details and a good number of photos from each flight are presented below.  It was definitely a fun weekend!  I left feeling very pleased and satisfied but also a bit worn out from all the effort and all the work required to execute these launches.  What a great way to spend the weekend!

Photo by Vern Knowles

The Oregon Rocketry flight line and LCO launch area on Saturday, July 19, 2008.  All three days were in the upper 80's or low 90's for temperature with clear skies and fairly low winds.  However, a smoky haze developed high in the sky on Saturday.  I assume that came from either a nearby forest fire or from all the wildfires in California.  It wasn't really a problem but as you can see, the sky was not very blue on Saturday afternoon.

Angelfire was prepped and ready to go Saturday morning on a 98mm Aerotech M1419 motor .  This would be "Sweet 16" for Angelfire having made fifteen previous flights.  This was also going to be my 50th M-motor flight!  I was looking forward to it with excitement but also some nervous anticipation.

Angelfire is 11 feet long, 5.2 inches in diameter and weighed 52.5 pounds with the motor installed. Expected altitude was 10,500 feet.  Angelfire carries two  Missile Works altimeters, an ARTS recording altimeter and a GPS radio downlink system.  The GPS system transmitted good data to the ground during the entire flight.  This allowed the entire flight trajectory to be captured and it is presented in a pseudo 3D view further down this page. 

This entire flight went really well!  The M1419 has a nice long burn of about seven seconds and it pushed Angelfire to 10,271 feet and 528 mph as measured by the GPS.  The altimeters deployed the drogue chute at apogee and the main chute at 1500 feet.  I was holding my breath as the main chute took a little longer than normal to unfurl and fill with air.  Fortunately it did and Angelfire was finally hanging safely on the main as it passed through about 800 feet to go.  It landed 2,928 feet from the launch pad and suffered no damage.  To say the least, I was thrilled!  Even after 50 M-motor flights they are still a lot of fun for me.

The animation at the left shows the Angelfire liftoff as a series of still photos taken 150 ms apart. 

Click on the animation to view it in a larger size.

The photo above shows Angelfire reassembled and ready to carry back. In order to make it easier to carry, lately I have been taking a towel with me to wrap around the airframe to serve as padding while holding Angelfire on my shoulder.  The towel is held in place with some nylon straps.  This makes it much more comfortable to carry Angelfire on those long half-mile hikes back to the car or back to the flight line.

You can also view this trajectory by downloading the data file at the link below and loading it into Google Earth.  You can then use all the normal pan, tilt and zoom controls in Google Earth to see it from any angle.  Just right click on the link below, save the file to a convenient place and then open the file from inside the Google Earth program.  If you already have Google Earth loaded on your system then you can probably just left click on the link below and it will fly you to the trajectory location.

Click on the charts above to see the altitude and velocity data reported by the GPS.  Each point in the plot represents one GPS reading.  The GPS updates at five times per second, therefore, the readings are spaced apart by 200ms.  The peak altitude reported by the GPS was 10,271 feet above the ground.  The peak velocity was 528 mph.  The descent velocity on the drogue chute was about 65-70 mph.  The descent velocity on the main chute was about 15-17 mph.

There were two MissileWorks barometric altimeters onboard.  One reported 10,402 feet and the other reported 10,669 feet.  The average of the two is 10,536 feet.  The GPS reported 10,271 feet.  This amounts to a 2.6% difference in altitude as determined by the barometric altimeters versus the GPS system.  That amount of error seems pretty typical based on my experience.

Click here to see these plots in PDF format

Wildfire was launched Saturday afternoon on an  AMW L1080 "Blue Baboon" motor.  It reached 3,997 feet and a peak velocity of 348 mph.  It was carrying a new payload module for this year that includes a 720p HD video camera and a GPS radio downlink.  The payload module is deployed at apogee and comes down on its own parachute.  The parachute for the airframe is also deployed at apogee.  This was the 25th flight for Wildfire!  The onboard video from this flight is presented further down on this page.

Photo by Tsolo T. Tsolo from RocketShots! © 2008

The airframe landed 0.5 miles from the flight line.  The payload module landed 0.73 miles away.  Both were within about 100 yards of the dirt road leading into the launch site so recovery was pretty easy.

Wildfire was recovered with no damage.

This was the second flight of Wildfire with a 720p HD camcorder onboard.  I choose the Canon TX1 digital video camcorder due to its small size, great picture quality and the fact it's relatively inexpensive. "New" units (never used) can be had on eBay for about $250 or less.  However, you also need to add a high speed 4GB SDHC card so that's another $40-$50 or so.  The camera will record 15 minutes of 720p HD video at 30 frames per sec on a 4GB card.  It can also record about one hour of standard 640x480 video.  The image presented below is a selected single frame from the video.

It's a fun ride in wide screen!     Unfortunately, it's not practical to present the full 720p HD version of the onboard video from this web site.  However, the compressed version here is still worth a look.  Click on either link below to play the on-board video.

View High Resolution MPEG version     (32 MB)

View low res Windows Media Player version   (20 MB)

This is a short 10 second video of just the liftoff as recorded by the "pad cam" setup about 70 feet from the launch pad.

View High Resolution MPEG version   (4 MB)

View low res Windows Media Player version   (3 MB)

You can view this trajectory by downloading the data file at the link below and loading it into Google Earth.

Click on the charts above to see the altitude and velocity data reported by the Wildfire GPS.  Each point in the plot represents one GPS reading.  New readings were captured every 200ms.  The peak altitude reported by the GPS was 3,997 feet above the ground.  The peak velocity was 348 mph. The descent velocity on the main parachute was generally around -15 mph.  However, the GPS system is part of the Wildfire camera payload module. That module is deployed on its own parachute at apogee.  Therefore, it is the descent rate of the payload module that was reported by the GPS.  Not the descent rate of the airframe.  Interestingly, if you look closely at the velocity plot in the time span between about 100 and 120 seconds, you will see the descent rate dropped to about -3 mph for two short intervals of time.  I assume that indicates there was a small updraft occurring at that point. That occurred while still about 1,700 feet above the ground.

There were two MissileWorks barometric altimeters on board.  One reported 3,835 feet and the other reported 3,940 feet.  The average of the two is 3,888 feet.  The GPS reported 3,997 feet.  This amounts to a 2.7% difference in altitude.  This amount of error seems pretty typical.

Click here to see these plots in PDF format

Coldfire was specifically designed to fly on the HyperTEK hybrid motor system.  This system uses ABS plastic for fuel and liquid nitrous oxide (N₂O) as the oxidizer.  More details can be found here.

Coldfire was put on the launch pad on Sunday morning, July 20, 2008 for what would be its fourth flight.  The HyperTEK system was configured as a K240 motor with a 6.4 second burn time and delivering a total impulse of 1440 Ns.  Peak thrust on this motor is only 75 pounds.

The two photos above show the ground support equipment needed for the hybrid motor.  The large black tank holds the liquid nitrous oxide.  It is connected to the filler tube via a solenoid valve that can be operated remotely.  The green tank holds the high pressure oxygen. It has two pressure gauges attached to it giving the tank pressure and the regulated pressure going to the motor.  The oxygen pressure going to the motor was set to 90 psi.  There is also a transformer mounted to the launch pad that generates the high voltage spark.  The oxygen flow and the high voltage spark are both controlled remotely. For more details see the HyperTEK product manual.

The root cause of the premature parachute deployment is not yet known.  Apparently one of the two  Missile Works altimeters decided apogee had been reached!  Although this was only the fourth flight of Coldfire, I have flown MissileWorks altimeters on a lot of other hybrid motor flights without issues.  There were no obvious wiring issues or any other problems found during the post flight inspection.  I still need to retest the two altimeters in a vacuum chamber but I doubt that will show anything either.  Both altimeters have worked just fine on the three previous flights.