Report

• Terminal Velocity II, Benjamin Wilkosz' rocket project page.

ASK 't Harde, 8 May, 2009 - This launch we had done some preparation beforehand, apart from packing the van on the Wednesday evening before the launch. Tuesday 21 April we had certified most of DARE's SRP rockets in Delft, due to the large number of rockets entered for this launch. Fortunately four out of 21 rockets were postponed to future launches. The level of the SRP rockets was better than earlier seasons. Also different from earlier NLD's was a third launch tower and a further cooperation of NAVRO and DARE people. In the command post DARE member Peter van Gemert was added to the usual command team. A total of four teams were available for the three launch towers, so each team had a break during the day. These teams consisted of a pyro-technician and an assistant and were manned by both NAVRO and DARE members. Apart from Kees Jan Groenendijk, DARE's Arjen Fraters was added as a second safety supervisor. All were colour coded by safety jackets: safety supervisor in blue, pyro-technicians in orange and their assistants in yellow.

As usual the arrival on site meant we unpacked and started to assemble the launch towers. Meanwhile preparation and certification of the rockets was to start, but the army tents we needed as preparation space had yet to arrive. But soon after the launch towers were erected, the army tents arrived and with a little help they soon were erected too. This increased preparation space was certainly needed with 17 rockets and motors to prepare. All rockets were made ready and certified, but Roel Hendriks' Spoetnik and SRP 14 "Mighty X" had problems with their electronics. The day ended with dinner and a great evening in the nearby "Golden Tulip de Beyaerd" hotel.

On Friday the launches could only start after noon, as there was a military unit firing 81mm mortars in the morning. This time was used to prepare the launch site and the launches. All pre-flight calculations had to be redone, as the wind conditions were at the limit for rocket launches. The first launch window of three rockets started with Benjamin Wilkosz' Terminal Velocity II. Unlike the launch of the first Terminal Velocity at NLD25 on 1 June, 2007 the Avalon 8 motor behaved and it propelled the rocket to an altitude of 2240m. The flight went fine, but peculiar was the deployment of the main parachute at 1200m. It was recovered almost undamaged. The second launch was that of Bert Koerts' Skywalker on an AeroTech F25W. It flew well, and although it was not recovered that day it was recovered later. The third launch was that of SRP 13 "Rockegg", which was one of the best SRP launches of the day.

The second window started with the launch of the René Hofsteden's AMRAAM 3. Its AeroTech I300T had a striking blue flame and it was one the fastest lifts off ever at a NLD launch. When recovered it was discovered it again had broken a fin. The beautiful finished SRP 14 "Mighty X" lifted off fine, but was caught by a gust of wind and became very unstable. The sixth launch was that of the SRP 15 "Menhir", which flew very fine and eventually it was recovered with an intact egg.

Pleun Punt's shortened PML D-Region Tomahawk was the first launch in the third window. The AeroTech J350W motor gave a spectacular yellow/orange flame and the rocket reached an altitude of 1275m. Its two-stage parachute system performed flawlessly and after a textbook flight the rocket was later recovered undamaged. Next was Team HARD's Zephyr. Team HARD is a team of five high school students of the Carolus Borromeus College of Helmond, who were assisted by DARE. The launch went fine, but the rocket parachuted early while still going upwards. Most likely its R-DAS detected apogee too early, probably due to the low angle the rocket was flying at that time. It was recovered intact however. The ninth launch was that of SRP 16 "ERROR" which flew fine, although its trajectory was curved due to the wind conditions. The SRP 16 team however had not made an error constructing the "Error", as it landed fine and its egg was recovered intact later.

The fourth window started with the successful launch of SRP 21 "Daedalus". It too was recovered intact. Next Roel Hendriks' Spoetnik misfired. SRP 17 "GSM" flew fine after it caught a gust of wind while leaving the launch tower and then recovering its trajectory. The parachute was to be activated by cell phone (GSM), but it failed to make a connection during descent.

The unstable flight of SRP 18 "Taco" opened the fifth window. It prematurely blew off its nosecone with parachute, but was recovered relatively undamaged. The following launch was that of Roel Hendriks' Spoetnik, without the malfunctioning electronics switched on. It flew very well and after reaching apogee it fortunately descended horizontally and thereby landing almost undamaged. SRP 19 "KRocket" was next, but it misfired.

Robin Trap's Bumble Bee opened the sixth window. Like other plump rockets the Bumble Bee could be followed the whole flight quite easily. During its descent the parachute became entangled, but when recovered it had only broken its nose cone (again). Its motor was a Mark Uitendaal K570. Next was SRP 20"Raket", which soon in flight became very unstable. It too descended horizontally.

The last two launches were both from DARE's launch tower, due to the launch lugs. The first of these was Bert Koerts' Abraham Cabeliau. Bert Koerts DM500 motor during its first test flight proved too powerful, as it tore apart the rocket in flight. The parachute functioned and all major parts were recovered. The last launch of the day (and just within the time limit) was that of SRP 19 "KRocket" and it flew well.

Also recovered was the lower half of the original Terminal Velocity which was launched 1 June, 2007 at NLD25 and a SRP rocket from an earlier season. When breaking up the launch site quickly, we all were caught by heavy rain, hail and wind speeds of up to 120 km/h. Nonetheless after 15 minutes of bad weather we continued and it all was done very quickly.

In retrospective it was a great launch, with a record number of 17 rockets launches, finished (just) in time. The setup of three launch towers with four pyro-technical teams worked very well, after some getting used to. Although it was not always clear who was assigned to a launch tower. Cooperation between NAVRO and DARE again was good, which is to be expected between two likeminded organisations.

Thanks to the staff of ASK 't Harde and all DARE and NAVRO members for their support (and enduring the bad weather).

See you all soon at the next launch!