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Bridle Testing of Steerable Parachute

A project log for High Power Experimental Rocket Platform

Experimental high power rocket with active stabilization, live telemetry, autonomous GPS guided recovery and HD video

j-m-hopkinsJ. M. Hopkins 06/20/2016 at 03:090 Comments

So one of the nice things that moving to California brings me is a consistent access to the beach and the winds that come along from the Pacific ocean. This allows me to finish my testing on the single skin steerable parachute, in this case bridle testing.

The bridle allows the canopy inflation geometry to be modified to conform the parachute to optimal characteristics for stable flight. This series of testing, is to establish the correct line length for each support line to optimize the canopy in numerous ways.

Inflation geometry must maintain shape in order to be effective, in this regard, canopy collapse is an issue that needs to be avoided, particularly in the face of increasing wind on the nose of the canopy. If too much horizontal air movement is combined with insufficient wing loading, then collapse and failure can be expected.

Modifying the left, right, and center cell rear edge geometry, changes the characteristics of stable flight and control surface reaction time. Meaning brake lines are more effecient, and wing loading transfers canopy rigidity for forward velocity.

Here is the test video, showing adequate control in 15-20 mph winds, but showing higher control surface reaction than anticipated (very twitchy). I believe that this can be altered by changing the center cell's rear geometry to transfer more of the air column to horizontal velocity, and relying less on the side cell velocity outputs.

Basically it's working well, but isn't as stable as would be preferred. This can be accomplished by adding length to the rear canopy edge control lines of the central cell.

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