Each flight log entry usually represents a launch or test day, and describes the events that took place.
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Location: Denzil Joyce Oval. (launch site #4)
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Conditions: Clear skies with warm temperatures and a medium breeze.

Rockets:

Team Members: PK, GK, Paul K and John K.

Number of launches: 8

On this day we flight tested the flight computer (FC) for the first time. It has been about 3 weeks since the last launch day because the weather was either too rainy or windy to fly. The FC is designed to provide a more reliable parachute deployment system, as well as provide other functionality. Full design details of the FC are available here.

Flight Day Events

• First off the launch pad was a newly rebuilt Frankovka III rocket because on the last launch day it was quite heavily damaged. The top bottle and payload section had to be rebuilt. On this first flight the video camera was fitted but no flight computer. The rocket took off at a bit of an angle, but flew fairly straight. We fitted twin parachutes to slow it down even more in order to try and stabilise the video footage. This was reasonably successful, but the two parachutes tangled around each other and so were effectively one larger parachute.
  
  This flight used the nosecone-off-at-apogee parachute deployment system, and as has happened on numerous occasions the parachutes deployed a little too early. Luckily we have much stronger main chute lines now so there is little risk of breaking them. 
• After this flight, we removed the nosecone and payload section from the rocket and replaced it with the prototype FC controlled parachute deployment nosecone. Since this was the maiden flight we opted to not include the video camera just in case ... well you know.
  
  We filled the rocket, packed the chute, and turned on the computer. I worked out from previous video footage of this rocket that the time to apogee was about 5.5 seconds. While on the launch pad we set this time delay on the FC. (The flight computer can set the time delay in 1/4 second increments.)
  
  We launched it and the flight profile was similar to the previous flight, angled slightly on take off, but then flew straight again. The rocket went through apogee, but the parachute deployed perhaps 1 to 2 seconds after that. The parachute deployed well and the rocket landed well also. We only used one parachute for these tests.
  
  
  Maiden flight Flight Computer
  
   
• We refilled the rocket with water, re-packed the chute and the rocket was ready to go. There was no fussing with balancing the nosecone or anything. You just turn on the computer, set the delay, arm it and launch.
  
  On each subsequent flight we reduced the deploy time by 0.5 second. With the final setting set at 3.5 seconds deployed the parachute at the point we wanted. Although the rocket reached apogee at around the 5 second mark, due to the parachute being tightly packed it was taking about 1.5 seconds to fully open. This allowed the parachute to fully open at apogee. We simply roll up the canopy and lines when we pack the chute, however, there are much better ways to pack a parachute for faster opening. We may do that on future flights.
• We were really pleased with the ability to finely adjust the parachute deployment. The rocket was launched at 120 psi on virtually all flights. For testing we wanted a slightly lower pressure so that the flights were more consistent. This rocket has flown at 140 psi on a number of occasions.
• We believe the strengthening breeze had a lot to do with the angling of rocket on take off. We observed this behaviour on previous breezy days.
• On one flight the rocket got stuck in a tree, but luckily it was within reach and was easy to bring down. That led me to think that perhaps the rocket should have a parachute line cutter so that should the rocket get caught in a tree by the parachute, then say after 30 minutes if the computer is not turned off it could cut the line.
• Last week we investigated a possible new launch site that is free of trees and has at least 300m radius of clearance, although in one direction it is about 2 km. When we build bigger rockets we will have to go to this site (assuming the owners will give us permission) as the park where we are is getting too small. On the last flight of the day the rocket drifted down range about 130 meters.
   

Flight Record

Design and Development

• Here is a video with a description showing a close up of the FC parachute deployment mechanism.
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• Next on the drawing board for the FC is to give it the ability to record air speed sensor data. This will mean also writing a bit of code to allow the FC to transfer its data to a computer for later analysis.
• The flight computer has its own page now here: Flight Computer