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Launch report: Altitude Measurement Method Comparison, Hubschrap 1                  03.05.2001


Gollump 4f rocket GOLLUMP 4f               f=fin

This is the rocket for our Altitude Measurement Method Comparison. On this page you find detailed flight data.

The fuselage of Gollump 4f is Gollump 2. The fins are my very first test fins made of  PET, all 3 with a different glue in between, recycled from my trash can. Good fins without additional work.

See here how to build  PET fins.

GOLLUMP 4f performed terrific, rising and falling straight like an arrow.


During the last GOLLUMP 4f  rocket rise phase I checked unnecessarily the stop watch "with one eye only", to see, if I had started it right. The rocket was as fast as before, when looking back I could not find it again in the sky. OK, I thought, no problem, the watch was started right, maybe Nobby takes the apogee time, and I still can take the total time if I listen to the "Thud" on impact. This was easy then, because impact was less than TWO METRES to my left, myself standing 40m away from the launcher! The "Thud" was loud, and consequently I was a bit frightened! But still I got the time measurement of the total flight and my friend a good SEAM measurement (SEAM=my Simple but Exact AltiMeter). It came down from 110 m=SEAM, resp. 109m = Dean's simplest correlation. Speed may have been around 120 km/h. Ouch! I doubt if I had survived, had it hit my skull. Have a look on the rocket nose:

Gollump 4f after impact This was the nose after the third return from over 100 m, landing on solid rocks each time. Surprisingly little damage. That could be pushed out again and reused immediately. The PLP and stone reinforcement of the nose is incredibly strong and worked exactly as planned.
Such a rocket is fun. It does not need an active deployment system.

We used one more rocket today. Here we tested a helicopter-like recovery for the first time. Helicopter = Hubschrauber in German. Two bottles of half a liter each, Robinson-coupled , sleeve for a smooth body. 4 RED PET fins on a modular skirt. Half of a tennis ball as a nose.
Various types of a heli design appeared over time, the first one reportedly being from Bill Robinson here.

Norbert with Hubschrap1 My friend Norbert with Hubschrap 1, ready to be pressurized. It was kind of late already (21h30), the camera used the flash.
Hubschrap 1, destroyed We should not have started with 8 bar pressure: Hubschrap 1 did not unfold its blades as planned and came straight down fast. Fortunately we took all flight data with SEAM and DEAN for our altitude comparison. On impact the 3 main parts were scattered in a circle of 3 m.
hubschrap1 destroyed The top bottle was just ripped out of the Robinson coupling.

Next time we use less pressure, maybe smaller fins, and the blades must be fixed more in front. Maybe a longer rocket and a lighter nose weight help as well.

to the detailed data of today's launches



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Stand / Last Revision:  17.05.2001

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