Part 5, 9 June, 2005
By Mark Uitendaal and Leon Krancher
- Spectre II, part 1, 30 June, 2004
- Spectre II, part 2, 7 July, 2004
- Spectre II, part 3, 22 October, 2004
- Spectre II, part 4, 13 January, 2005
- Spectre II, part 6, 23 September, 2005
- Spectre II, part 7, 2 January, 2006
- Spectre II, part 8, 15 April, 2006
Disclaimer: all liability waved! The contents of this page is presented for informational purposes only. Do not try to recreate any experiments presented in this page. The NAVRO and the author of this article cannot assume responsibility for any use readers make of this information. In The Netherlands it is forbidden by law to own this type of propellant if you do not have an exemption of the "Wet Explosieven Civiel Gebruik" (WECG).
Spectre II flight review
On 22 April 2005 we launched the Spectre II in single stage configuration. The reason for this configuration is that we didn't succeed in completing the booster motor. After three failed tests we decided to cancel the booster and only fly the second stage. This flight can be seen as a full system test. The purpose of this flight was to test the whole airframe, recovery system, motor and camera system.
The day before the launch we arrived on the ASK 't Harde fairly late. Probably around half past three we drove through the gates of the military compound. This meant that there wasn't much time left to prep the rocket and to let it be validated by NAVRO officials. But since Spectre II is designed to be fully prepped in under one hour we had plenty of time to eat. The validation trials of NAVRO went very well, and everything such as Cp and Cg was in good place. After this we went to the bar. After a really cool evening with lots of friends we went to our sleeping quarters, with the knowledge that our wake up call went on half past six!
The following (very early) morning we acclimatized slightly by our breakfast. Man, this was really early! Half past seven we were ready to begin with the preparations for the flight. First, we erected the two wooden receiver towers. One of the towers was only 15 meters away from the rocket and has some cables to a video recorder with a four hour video tape in it. The second tower was positioned 300 meters away from the rocket, near the launch button. Both towers need 230 volts to work, so the electric generator of NAVRO had to be started. After some trouble with the first tower and with the time pressure we decided that Leon was going to prepare the ground segment (the receiver towers) and Mark the rocket.
Mark went to the building where the Spectre II was stored and activated the homing beacon probably half past nine. After the loading of the parachutes the rocket was ready for transportation to the launch pad. The launch platform of NAVRO is a very sturdy and rigid construction with a long rail of six meters. We are very glad that it is so tall, because in our single stage configuration the rocket had left this six meter tower with a mere velocity of only 20m/s which is just the minimum set by NAVRO.
Then about 9:45 the completed rocket was transported to the launch tower and there was a opportunity to make pictures of all the assembled rockets. In total there were four other rockets, all worked out beautifully, so a lot of pictures were shot!
After the beautiful first flight of Robin Trap's "Weasel 29" the moment had come. Spectre II was going to be launched. After a countdown of one minute the moment was there. A quick tuning of the receiving tower near the launch post resulted in a complete loss of signal because our "noise filter" of the video-recorder kicked in. Too bad, but there was no time to fix it, and there was a backup receiver only 10 meters from the launch pad. When the command "ignition" was called, the rocket responded with a small puff of smoke. The J420-SB roared to life and pushed its heavy burden along the rail. After 6 meters the rail ended and the rocket was in flight for the first time!
The rocket flew with an astonishingly low speed to an altitude of approximately 250 meters. The maximum velocity was a mere 60m/s (216km/h). The motor performed as expected, giving the right thrust profile, which resulted in the following acceleration figure:
On apogee the drogue parachute was ejected with a charge of 1.5 grams of black powder. Half a second later a redundant backup charge of 2 grams was fired by the secondary flight computer. The first charge and the separation was picked up by the R-DAS unit with a acceleration spike of 33G! After opening the drogue performed as expected and reduced the velocity to 19.2m/s (Design velocity was 20m/s).
After 2 seconds the main parachute was fired. Opening of this big piece of cloth lasted for 1.25 seconds. The acceleration spike was seen on R-DAS for -23g (the minus sign because R-DAS was now turned upside down). This value was frighteningly close to our calculated value of -23.8g (Damn, seems that my study finally pays off!)
The descend velocity of the first part of the main descend was 4.2m/s and the impact velocity around 6m/s. This couldn't be explained.
After landing, we were very happy to see that our video system had worked! A very spectacular ascend was caught on tape. Unfortunately, the top part and the landing were covered with a lot of noise.
This flight was a complete success! All systems worked like expected and no new things popped up, although some changes will be made for the next flight:
- Camera system: A new and improved system will be installed. This will be using a technique called "on board capturing" The camera will be a Philips DMVC 1300K Pencam with a resolution of only 320X280 and a frame-rate of only 21 fps. This unit has an internal capacity of 128Mb. This will give us probably around eight minutes of recording time, but without noise! The unit will be modified and attached in the electronics compartment. We will keep you updated!
- Next time, we WILL fly with a booster! We will "test our butt off" to fly the Spectre II on April 2006 to an altitude of 1.5km. Our failures probably got something to do with the paper inhibitors, so we will modify them and test that new motor. We will keep you updated!
Next part: Spectre II, part 6, 23 September, 2005