On Saturday at our local NOTRA Tripoli Launch, we sent a 4" LOC Goblin up on an I327DM. I used a quantum in the nose, only using the drogue function to deploy the parachute which was bundled with a chute release and set to release at 500 feet.
I downloaded the detail file from the quantum just now because I wanted to see how efficient the parachute I stitched up was on the decent. The graph of both raw altitude and filtered altitude are show below vs the elapsed time.
My question is this, you can see where the chute smooths out the rate of decent at the point shown below. I calculated the actual descent rate ( I think), by subtracting the altitude where the rate stabilized from the altitude on landing, and in a similar fashion, the elapsed time. That came to 352 feet in 41 seconds. By the powers of higher math, I calculate that to be 8.6 F/S.
In excel, mousing over the same data range for the velocity in both raw velocity and filtered velocity, excel calculates the average at 10.0 and 10.9 respectively. While those are pretty close to 8.6, which I believe to the no kidding decent rate, I am surprised by the discrepancy. Anyone have any theories?
I downloaded the detail file from the quantum just now because I wanted to see how efficient the parachute I stitched up was on the decent. The graph of both raw altitude and filtered altitude are show below vs the elapsed time.
My question is this, you can see where the chute smooths out the rate of decent at the point shown below. I calculated the actual descent rate ( I think), by subtracting the altitude where the rate stabilized from the altitude on landing, and in a similar fashion, the elapsed time. That came to 352 feet in 41 seconds. By the powers of higher math, I calculate that to be 8.6 F/S.
In excel, mousing over the same data range for the velocity in both raw velocity and filtered velocity, excel calculates the average at 10.0 and 10.9 respectively. While those are pretty close to 8.6, which I believe to the no kidding decent rate, I am surprised by the discrepancy. Anyone have any theories?