Tag Archive: Block I

Oct 05 2017

Progeny Mk5 Design Review & Block I

Progenitor teams have been spending the last few weeks pouring over data gathered from the flights of the Progeny Mk4 and Mk5 to see how they have compared in order to judge the overall performance of the new Mk5 after its initial series of 5 launches last month to test our automated control software. The Mk5 sports the M-315 automated control unit and replaces the old control unit with an extra battery, which makes it only 36kg heavier than the Mk4 when both lack payload instruments. The inline control unit adds a bit of length to the third stage, with the Mk5 measuring in at 9.5m tall versus the Mk4’s 9.3m. The only other variation for the Mk5 was that we launched it at an initial pitch of 87° versus the Mk4 which was launched at 85°. While we expected most if not all of these launches to reach similar heights of the Mk4 or even exceed them, none actually did.

The two related reasons behind the inability of the Mk5 to surpass the Mk4 were initial pitch and coast duration between staging. Although the rocket launched at 87°, the initial drag at the nose pitched it up to as high as 89.4° within 1 second. Ascending so close to vertical gave the Mk5 a slower start due to having to fight gravity more, and it never caught up to the Mk4 in terms of ascent speed, even if we account for the Mk4’s slightly lesser mass. Since the rocket was standing up so straight, it also took a longer time to pitch over, which meant the coast periods were longer, during which the Mk5 lost more speed than it would gain back between the first and second stages compared to the Mk4. Let’s go to the graphs!

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