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events that took place.
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Day 94 - Mark 3 Stager Test Flights
16th May 2010
First Mk3 Stager prototype bottom view...
...and the top view.
Setting up for the first flight.
This did not quite go according to plan.
Setting up again for the third flight, which
worked properly. Top of rocket bares a few
scars.
Fourth flight was also less than optimal.
13th June 2010
In this image you can see the locking tab
tied to the launcher. This was done because the
sustainer was too light.
Unfortunately, the tubing slipped out of the
cap on two launch attempts, and the rest of the
day was aborted.
Here you can see the parachute attached to
the side with a 'piano hinge'. A wire leads to
the sustainer to deploy the chute after staging.
4th July 2010
Cool but clear morning made for a good
launch day.
Shortly after staging. The sustainer is only
a single bottle without fins.
We had 5 out of 5 successful launches at the
end of the day.
1st August 2010
Two rockets ready for trial flights of the
Mk3. Stager. Sustainer is 2L and the booster is
3L.
The sustainer was unsupported to test the
loading during acceleration. Larger sustainers will
need support during high acceleration.
The kids are now well trained to help set up
the launch pad.
Rod and Madolyn look on.
Launch pad set up crew retreat and the
rocket crew steps in.
Too many wires and ropes!
First launch of the day was flown at 110psi.
The park is too small to fly at higher
pressures.
Shortly after staging.
Launch pad setup crew changes focus and
becomes the recovery crew.
Second launch ... we keep aiming for the
moon, but can never quite get there.
Remind me again dad why we are in the middle
of the oval on a cold morning?
"Where does this bit go?"
Second launch also was a success. Sustainer
reached around 300- 350 feet.
The breeze carried rockets down range quite
a ways.
Precious cargo.
How many rocketeers does it take to fill a
bottle with water? ... Three generations worth!
Launch control center overlooking the launch
pad.
Sustainer long gone, the booster falls just
prior to opening its own chute.
On the last flight the sustainer landed
about 10 meters up in a tree.
Hunting instincts kick in as we hurl a
weight tied to string to try to snag the correct
branch... again ....
.... and again.....
...and again ... until we eventually managed
to get the rocket down.
Date:16th
May - 1st August 2010
Location:Denzil Joyce Oval, NSW, Australia
Conditions:Cool, clear skies, wind >10km/h
at times.
Team Members at Events:PK,
GK, PaulK, JohnK, MC, RC
The following update is a compilation of
4 different launch events spread over 2.5
months as we developed and test flew the Mk
3. staging mechanism.
Mk 3. Staging Mechanism
A question we are often asked is how to
build a simple staging mechanism. The one we
normally use on
our bigger rockets, is complicated to build, relatively
expensive, fairly heavy and is not really
suitable for smaller rockets. We normally
recommend the
crushing sleeve mechanism that
has been used for many years, as it is
simple and effective. The
Mk2 stager
was an all mechanical solution, and though
it worked (sometimes) it wasn't
really practical as it used many custom parts and
took a long time to make.
So with the Mk3 stager we decided to
take the approach where anyone should be
able to build it out of common inexpensive
materials without needing special tools. It
also had to be suitable for
smaller rockets. The other main criteria
was that the sustainer should use the
standard 9mm Gardena nozzle to allow it to
be used with our regular rockets. The Mk3
design is partly based on
Richard Wayman's
RIG stager that fixed the Gardena collar
permanently and allowed the inner mechanism
to move. (here are the RIG
Stager details) The mechanism activation though is
based on a different principle and is
independent of pressure as we did in the
Mk1. Stager.
For the first 3 sets of trial flights we used a
Baryon I
booster made out of a single 2.1L spliced
pair. The sustainer was made from a single 1.25L
bottle without any fins or recovery system.
Since we were really only concerned with
whether the staging mechanism worked or not,
we did not care about the sustainer flight
profile. A simple bottle is also a lot
easier to replace if the staging mechanism
fails.
On this day we flight tested the Mk3.
stager for the first time. The stager used
the weight of the sustainer alone to keep it
locked in place.
Flight
Pressure (psi)
Notes
1
100
Staging mechanism failed to
release sustainer and the whole
rocket lawn darted. The stager
survived without damage. - FAIL
2
100
Stager released sustainer while
still being pressurised on the pad.-
FAIL
3
100
Stager successfully released
sustainer on booster burn out. -
SUCCESS
4
100
Staging mechanism failed to
release sustainer and the whole
rocket lawn darted. The stager was
damaged beyond practical field
repairs. - FAIL
The one successful flight was encouraging
in showing that the stager can work, but it
looked like there wasn't enough force to
separate the stages. Since we damaged the
only stager we had, we had to stop after the
4th flight.
Because the sustainer failed to release
mid air, we added a stronger spring for the
next set of test flights. With the
stronger spring there was a higher chance of
the light sustainer being released on the pad, so
a locking tab was added and tied to the launcher. This
is
released on launch and the acceleration
keeps the sustainer in place.
Flight
Pressure (psi)
Notes
1
~80
While pressurising on the pad
the pressure caused the bead in the
booster end of the clear tubing to be pushed
out and as a result the tube slipped
out of the booster cap causing the
top part of the stager to blow off.
- FAIL
2
~80
Field repairs required us to
replace the lost bead with an
equivalent (a small stick), however the same problem
occurred on this attempt and the top
of the stager was blown off again. -
FAIL
This was only a minor issue, but we had
to abandon the launch attempt as we did not
have a way to fix it in the field.
So we
replaced the bead with a pen tip and secured
it in place with a couple of loops of wire.
For these launch trials we also secured the
non-return valve inside the Gardena coupling
with a wire loop to stop it potentially slipping
out of the tube. We also replaced the bead
with a pen tip and secured it again with
wire. These launches also used the
locking tab attached to the launcher, as
well as the stronger spring.
Flight
Pressure (psi)
Notes
1
110
Good launch. Stager released
sustainer at booster burnout -
SUCCESS
2
110
Good launch. Stager released
sustainer at booster burnout -
SUCCESS
3
120
Good launch. Stager released
sustainer at booster burnout -
SUCCESS
4
120
Good launch. Stager released
sustainer at booster burnout -
SUCCESS
5
120
Good launch. Stager released
sustainer at booster burnout. Fin
was damaged on landing - SUCCESS
Water fill on these flights was 700mL for
both sustainer and booster. The last flight used 800mL in
the booster.
Both booster and sustainer used a 9mm nozzle.
These flights were quite successful in
releasing the sustainer at about the correct
time, when the booster stopped producing
thrust. We again used just a simple bottle
as the sustainer without fins. It was very
evident at how unstable the sustainer was
after release.
This set of tests involved using a larger
booster (Baryon
IV) and sustainer (Tachyon
VIII) to test the stager at higher
loads. Originally we were going to take
these to Doonside, but because of the launch
cancellation we performed the tests at our
local park at lower pressures.
The booster has a 3.1L capacity and uses
a 9mm nozzle. The sustainer has a 2L
capacity and also uses a 9mm nozzle. The
better combination would be a 15mm nozzle on
the booster and a 7 or 5mm nozzle on the
sustainer.
The parachute on the boosters was deployed
using the piano hinge method we use on our drop-away
boosters. It is a simple and reliable method
of deploying the parachute after staging.
Flight
Pressure (psi)
Notes
1
110
Good launch. Stager released
sustainer at booster burnout -
SUCCESS
2
110
Good launch. Stager released
sustainer at booster burnout -
SUCCESS
(stager damaged because how the
parachute was attached as it hit the
ground stager first.)
3
110
Good launch. Stager released
sustainer at booster burnout -
SUCCESS
(stager damaged when rocket was
dropped by one of the crew after
initial landing.)
On all three flights the stager performed
well though one was slightly damaged when it
came down stager first and hit the ground.
The other was damaged when one of the crew
accidentally dropped the booster onto the
stager after picking it up off the ground.
Both repairs are minor and easily fixed.
Dad also had to make a new adjustable
ring brace for the medium launcher as the
ones we normally use are too small to fit
the larger fins on these boosters.
The sustainer got stuck in a tree on the
last flight. It wasn't too far up so we
tried using a line with a heavy weight on
the end to hook over the branches. After
about an hour of trying, we gave up, and
came back later in the day with stronger
rope to help get the branches bent over far
enough. We were happy to get the rocket back
in one piece.
Here is a highlights video of some of
test flights over the last 2.5 months:
