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Highlights of recent developments on the MiniSShot Project
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- As notified in the May 4-10 Weekly Activity Report, Craig Strudwicke
flew 'This Way Up' for 5 flights as planned last Sunday. In addition to
an accelerometer and magnetometer, the instrumentation included a rate
gyro operating a servo driving a pair of fins operating in differential
mode for active roll control. A summary of the roll performance is
provided here:
http://sugarshot.org/downloads/roll_31-5-09_all_flights_summary_5_pgs.pdf
A note about the flights:
Flights 1,2,4,5 - 2 grain 60mm motor. The high frequency component and
odd roll control behaviour shown in flight 2 is likely due to a loosened
threaded coupling between roll controller and bottom half of vehicle.
Flight 3 - 50mm Hybrid motor that CATOed at approx 1s. from liftoff.
The success of Craig's active vehicle roll control is encouraging and
may bode well for future SS2S projects. Tailoring the vehicle's roll
can potentially command a specific angular velocity during boost or
whatever other part of the flight and then command a zero roll and a
specific heading/roll angle, with the latter condition allowing for
better on-board video.
- Craig has also updated the battery survey with the data for Lithium
Manganese Dioxide dry type:
http://sugarshot.org/downloads/ssts_battery_chemistry_survey-data_rev2.pdf
In a nutshell, with regard to specific energy (Wh/g) and energy density
(Wh/cc) the Lithium Manganese Dioxide comes out in front of everything.
However, it does not come close to the LiPO or Lithium Ion for specific
sustained discharge current.
- Andre has successfully tested the vibration sensor circuit, using a
mobile phone to generate vibration. The plan is to have the sensor
mounted on the rocket motor for the next MiniSShot test firing.
Video of test:
http://www.youtube.com/watch?v=Qgbh5q8r6iU
- Chris King provided the following progress to report:
1. I received the new M-Tek igniters. They look very similar to a Davey
Fire type and appear to be very high quality construction. I will use
these for the Chute Controller tests coming up next week.
2. I have received the replacement DATAQ. I have also constructed a
small cabinet or box to package it. The box has better connectors to
interface the various sensors. It will greatly improve the ease and
reliability of the set-up in the field.
3. I have built a switch box that will allow the current launch
controller to fire both of the MiniSShot's phases. Testing starts this
weekend.
4. I have started evaluation of the thermocouple amplifier assembly and
integration with the DATAQ. So far the temperature does not track
properly. The primary suspect is the thermocouple itself.
5. I have a preliminary design of the new sensor mounting jig for the
launch backbone. It will allow for slight adjustments in the field such
that we can eliminate the bungee cords. I will start getting parts this
weekend and begin construction if time permits.
6. The radio beacons that were run-over by a truck a few weeks back are
repaired. I have not had a chance to test their range over open land.
This will be coordinated with the Chute Controller tests next week. See
the attached photo.
7. I have added the Featherweight altimeter to the Chute Controller
sensor card. See the attached photo. The featherweight seems simple
enough to use but the documentation is a bit difficult to wade through.
It will take awhile to build confidence in my understanding.
Photos:
Recovery Beacon transmitter modules:
http://sugarshot.org/downloads/rocket_xmtrs_011.jpg
Featherweight and Chute Controller module for GHATR rocket:
http://sugarshot.org/downloads/rocket_xmtrs_002.jpg
- Richard has cast four of the six remaining "casting tubes" needed for
the upcoming MiniSShot motor test firing. A total of 12 such tubes are
needed, six for the aft chamber (which have already been completed, see
last week's report), and six for the forward chamber. The ablator for
the forward chamber is of a different composition that is lower in
density, made possible due to the less severe heat load.
Raw materials for the ablator:
http://sugarshot.org/downloads/ssa-2_materials.jpg
Rough cast tubes:
http://sugarshot.org/downloads/ssa-2ascast.jpg
- This past weekend, Matt Cambell reports that he had a chance to chat
with Kevin Baxter, president of "Friends of Amateur Rocketry" (FAR,
http://far.pyroinnovations.com/ ). The FAR test site is where we have
test fired our MiniSShot motors. Matt reports that Kevin "was excited
about our project
and offered the large horizontal test stand for our use. The stand
currently consists of a concrete pad
with recessed bolts and a large concrete bulkhead (looked like it was
about 24" x 60" x 102" from the distance) with more bolts available.We
would have to provide our own stand, backbone and sled". This is
excellent news and will greatly facilitate testing of our larger
DoubleSShot and ExxSShot rocket motors.
- Long time SS2S supporter and current Silver Donor Cliff Bates has made
another donation, this time for $150. Thanks again, Cliff, for both your
moral support and your financial support !
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Expenses have been adding up and our funds are dwindling. To help keep
SS2S alive and thrivng, help out by making a contribution to the Sugar
Shot to Space program.
http://www.sugarshot.org/sponsors.html#Donors
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