Launch report: Altitude Measurement Method Comparison, Hubschrap 1
||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
See here how to build PET fins.
GOLLUMP 4f performed terrific, rising and falling straight like an arrow.
GOOD LUCK! GOOD
LUCK! GOOD LUCK!
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:
||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
||My friend Norbert with Hubschrap 1, ready to be pressurized. It was kind
of late already (21h30), the camera used the flash.
||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
||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
to the detailed data of today's launches