Here is a couple of videos from my latest project that was launched in
October 2015. The goal of this project was to fly above 50.000feet on a sugar
propellant (KN/Dextrose). The rocket was a boosted-dart powered by a newly
developed 110mm diameter O-9600 (36kNs) sugar rocket motor. The design was
largely based on my first boosted-dart project that flew to +35.000feet in
April 2015. Video about this earlier project can be seen here:
https://www.youtube.com/watch?v=9vcAQPJUqV0
An entire project from the start of motor development to an actual flight took
five weeks. It took three weeks to develop the motor and another two weeks to
fabricate the flight hardware and the new launch rail. The rocket construction
is very simple. Booster motor has threads on both ends. Booster fincan is
screwed on the aft end and a short section of aluminum tube holding the booster
electronics and parachute is screwed to the forward end of the motor. Then the
transition cone is attached to the booster. Dart fincan/boattail assembly is
made from stainless steel. Dart fins are also made from stainless steel and are
laser welded to the fincan. Dart is 50mm in diameter and weighs 9,3kg
(20,5lbs). Body tube is made from filament winded fiberglass. There were two
altimeters on-board the dart. Perfectflite Stratologger CF and an ARTS-2. A
BigRedBee 70cm HP GPS was used for dart tracking. Lithium batteries were used
for power. Dart nosecone is a 8°cone and is turned from a solid mild steel.
Flight was great. When the button was pushed more than a ton of thrust made
sure that the things started to move quickly. Booster burned out in 3,5 seconds
at an altitude of 4000 feet. Dart successfully separated and coasted for more
then 50 seconds to a measured altitude of 57.359feet. 18inch parachute was
deployed at apogee and the dart safely landed 8km from the launch site, where
it was recovered two hours later. Booster recovery system unfortunatelly didn't
deploy and the booster made a ballistic impact about a kilometer from the
launch rail. Impact site was not located and a cause of malfunction remains a
mystery. Overall I consider the project to be a success. The altitude goal was
achieved and the motor was successfully flight tested. What's next?
Next project will be a two stage rocket. The plan is to use the same booster
motor for a first stage and a yet to be developed 55mm, 5kNs sustainer motor
for a second stage. Preliminary simulations show that this combination would be
able to fly to well over 100.000feet.
https://www.youtube.com/watch?v=AB_TpaJn72k
https://www.youtube.com/watch?v=BWsqNXpL7qY
Andrej Vrbec