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Highlights of recent developments on the MiniSShot Project
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-Exciting news! There were a number of major developments that occurred
over the past week:
- Casting of the propellant grain segments took place on Saturday, April
5th. This happened despite some last minute glitches including one which
involved undersized drum mixers, and required some frenzied
brainstorming to solve. A total of 24 segments were cast, enough for two
firings. Propellant casting was accomplished by Matt Campbell, Rick
Maschek and Brent Dougherty. Sam Grado, who supplied the KN and Sorbitol
at a highly discounted price, also participated and played a key role
in prepping the KN.
Based on reports from some of the folks involved, a great time was had
by all who participated. Excellent teamwork help accomplish a very
challenging task -- hats off to this group of guys!
(photos of the event will be posted in the days to come)
- Roman has completed fabrication of the nosecone. This is no ordinary
nosecone. Meant to serve as a prototype of the nosecone design for 100
km eXSShot, it incorporates some key features that will be essential
for that project. Minimum mass combined with high strength, tight
tolerance aerodynamic profile, and resistance to thermal heating. The
first two criteria are met through the use of a sandwich design
featuring thin glass skins and a nomex honeycomb core. Aerodynamically
efficient profile was achieved with the use of carefully manufactured
moulds. Resistance to thermal heating is achieved with a lightweight
ablative tip. Roman was able to achieve the mass target of 245 grams,
and in fact, was 5 grams under. Roman estimates he spent 500 hours total
on producing this nosecone -- if he were to charge an hourly rate of
$50/hr, this would be a $25,000 nosecone! A huge thank-you goes out to
Roman for his incredible dedication (and blood, sweat and tears) to this
nosecone project!
Photo of Roman holding the nosecone:
http://www.sugarshot.org/downloads/nosecone/rl_and_nosecone.jpg
- Craig has completed a draft copy of a User Manual for the DTMF boards.
- Correction: Mario Escalante, who has been assisting with the CAD
modeling, actually lives in Guadalajara City, Mexico (not Brazil as
reported last week). Our apologies, Mario!
- Richard has successfully hydro-static proof tested the delay plug
which is cast into place in the motor's midbulkhead. The delay plug had
been cast to its "minimum thickness" to simulate the critical loading
condition of full chamber pressure at motor burnout when much of the
plug has been burned away. The proof pressure was 1130 psi (77
atmospheres), which represents 110% of max. operating pressure of the
motor (MEOP).
Here are photos of the test setup:
http://sugarshot.org/downloads/delayplug_hydro1.jpg
http://sugarshot.org/downloads/delayplug_hydro2.jpg
This test verified the design and Finite Element analysis of the delay
plug done earlier by Andrew Burns. Great work, Andrew!
http://www.sugarshot.org/gallery/burns/FEA_stress_1.jpg
- Shawn McHatten, Andrew Nowakowski and Richard held a couple of Skype
conference calls earlier this week to discuss revamping of the Sugar
Shot website. Good progress was made in deciding what changes are needed
to make the site more relevant, up-to-date, user-friendly and to provide
more details on the people behind the projects. Action items were picked
up by all three participants.
- Hans has been working on a horizon sensor and (optional) 3 axis
magnetometer as part of an upgrade to the avionics. In addition, Hans is
continuing to refine the Chute Controller software.
- Nicholas Lynch and Dustin Brown are our two latest Silver Level
donors. Nicholas has contributed $100 to our effort, and Dustin has
kicked in another $25 which takes his accumulative total to $125. A
heartfelt thanks to these two special supporters of SStS!
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Contributions to the SugarShot program are always welcome and always
badly needed. For more information, see:
http://www.sugarshot.org/sponsors.html#Donors
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