It's not often that I blog about amateur high power rocketry in this space since I essentially have just about ended (but not entirely!) my efforts in that hobby as of late. Between the time (and expense) of running my telescope(s) and doing all other manner of hobby and hobby-like activities rocketry has taken back stage. It was getting really difficult to lug around all the equipment to the rocket field on the eastern shore of Maryland, not knowing if the weather conditions were going to be suitable for launch until the last minute. And add to that, taking the better part of an entire day prepping my large rocket(s) and then having to chase them down when they drift to the edge of the launch site and carry them back to the launch area. Some of my largest rockets weigh in at 50-150 lbs. plus. Gets to be problematic in the summer heat, and almost equally so in the winter chill at my age. I still plan to continue in the hobby, but only building and flying small to mid-size rockets.
However, in the most recent Sport Rocketry magazine is a feature article on Project Final Cut, an amazing rocket built and flown by Doug Gerrard of Socorro, New Mexico. This incredible project is an 8" diameter rocket with a 98mm central motor mount and six 54mm strap-on boosters. It is over 15ft tall and weighs in at just under 190lbs at liftoff. Doug's passion is launching rockets and capturing photographic footage and stills. For the last 33 years nearly all his rockets carried camera payloads and all of them were named after photography/movie terms. This project, likely his last, is appropriately named "Final Cut". On board there are 13 cameras, 12 altimeters/timers and 7 motors. The central motor is a 15-second burn N1000 and the outboards are six K270 long burn motors. All seven were planned to ignite at once to lift the massive rocket into the sky. Then at about T+7.5 seconds, the strap on boosters would separate in pairs while the main motor continues it's burn. Although the flight had a few issues, the rocket reached an altitude of 11,000 ft. and landed successfully not far from the flight line.
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| Final Cut launch |
With cameras in the main rocket, in the strap-on boosters and on the launch tower, the footage captured was incredible. Looking to the rear of the main body tube was a special high-speed Chronos 1.4 camera with a 1" sensor that records at 1080P at 1000 frames per second. Video of the launch can be found on Vimeo (https://vimeo.com/558878230) - a must see!! One thing to keep in mind while watching the video is that all the clips are played back in slow motion. This makes the rocket appear to take a long time to take off and the sound of the motors is a thundering roar. In real time amateur rockets accelerate rather quickly; usually in excess of 5gs, the lowest recommended acceleration for safe launch since these rockets are fin stabilized and need to move at 30 -45 ft per second to achieve flight stability. Because all of the motors used in Final Cut were long burn motors, the rocket only accelerated at a max acceleration of 4.5gs, and therefore the team constructed a special launch rail that was twice the normal 12ft length to keep the 'pointy-end' pointing up until the rocket reaches the required minimum velocity for fin stabilization.
It's projects like Final Cut that make me want to get out there and get another one of my birds in the air. Maybe even design a similar rocket. We'll see :)
Final Cut launched at NAR's National Sport Launch (NSL 2021) in Alamosa, CO, during the last weekend of May. Additional details can be found at: NSL 2021 and NSL 2021 - Facebook, as well as in the Sept/Oct 2021 issue of Sport Rocketry.
