To evaluate whether a baffle on a Robinson coupling can
prevent the blow-through effect.
Experiment Setup
The 8L
Polaron
III rocket was set up on the
launcher and tied down for this experiment. The standard static
test fire procedure was used. A video camera was set up to film
the lowest bottle to see the water's behaviour.
The baffle being tested replaced
the coupling nut and is essentially a
plugged tube with four 6mm holes radiating
out from the center. Because the baffle is
so close to the base of the bottle, the
bottle lobes help direct the airflow
downward to the surface of the water.
Setting up for static fire tests.
The rocket is attached to the launcher with
the 2 meter extension.
The baffle that screws onto the Robinson
coupling, You can see the air holes on the side.
The rocket is manually fired.
Static Fire Tests #5 and
#6 - Baffle
This test shows how water behaves inside
the lowest bottle with
the baffle in place. It seems to solve the
blow through problem as well as the water
being pushed up against the sides during the
air pulse as was seen in the previous tests
#1 and
#2.
Launch
Pressure (psi)
Notes
1
110
9mm Nozzle, baffle on lowest
coupling
2
110
7mm Nozzle, baffle on lowest
coupling
Frame from the video showing just prior to
launch.