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-<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>YikStik</title><meta name="generator" content="DocBook XSL Stylesheets V1.73.2"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="book" lang="en"><div class="titlepage"><div><div><h1 class="title"><a name="id2322390"></a>YikStik</h1></div><div><h2 class="subtitle">A NAR L3 Certification Rocket</h2></div><div><div class="author"><h3 class="author"><span class="firstname">Bdale</span> <span class="surname">Garbee</span></h3></div></div><div><p class="copyright">Copyright © 2008 Bdale Garbee</p></div><div><div class="legalnotice"><a name="id2577753"></a><p>
- This document is released under the terms of the
- <a class="ulink" href="http://creativecommons.org/licenses/by-sa/3.0/" target="_top">
- Creative Commons ShareAlike 3.0
- </a>
- license.
- </p></div></div><div><div class="revhistory"><table border="1" width="100%" summary="Revision history"><tr><th align="left" valign="top" colspan="2"><b>Revision History</b></th></tr><tr><td align="left">Revision 1.2</td><td align="left">12 January 2009</td></tr><tr><td align="left" colspan="2">
- Document firmware bug in miniRRC2 and possible impact on flight.
- </td></tr><tr><td align="left">Revision 1.1</td><td align="left">5 December 2008</td></tr><tr><td align="left" colspan="2">
- Remove embedded images in favor of references to gallery.gag.com
- </td></tr><tr><td align="left">Revision 1.0</td><td align="left">28 October 2008</td></tr><tr><td align="left" colspan="2">
- Recording results of first, and only, flight attempt.
- </td></tr><tr><td align="left">Revision 0.5</td><td align="left">27 September 2008</td></tr><tr><td align="left" colspan="2">
- Building checklists
- </td></tr><tr><td align="left">Revision 0.4</td><td align="left">17 September 2008</td></tr><tr><td align="left" colspan="2">
- Documenting the build process as it happens
- </td></tr><tr><td align="left">Revision 0.3</td><td align="left">29 March 2008</td></tr><tr><td align="left" colspan="2">
- Incorporate ideas from James Russell during initial L3CC review
- </td></tr><tr><td align="left">Revision 0.2</td><td align="left">27 March 2008</td></tr><tr><td align="left" colspan="2">Cleaned up for initial review</td></tr><tr><td align="left">Revision 0.1</td><td align="left">16 March 2008</td></tr><tr><td align="left" colspan="2">Initial content</td></tr></table></div></div></div><hr></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="chapter"><a href="#id2565537">1. Introduction</a></span></dt><dd><dl><dt><span class="section"><a href="#id2565574">Why "YikStik"?</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id2557207">2. Design</a></span></dt><dd><dl><dt><span class="section"><a href="#id2557213">Overview</a></span></dt><dt><span class="section"><a href="#id2557231">Rocksim File</a></span></dt><dt><span class="section"><a href="#id2557244">Drawing from Rocksim</a></span></dt><dt><span class="section"><a href="#id2557261">Airframe Tubing</a></span></dt><dt><span class="section"><a href="#id2557277">Nose Cone</a></span></dt><dt><span class="section"><a href="#id2557288">Fins</a></span></dt><dt><span class="section"><a href="#id2608670">Centering Rings and Bulkheads </a></span></dt><dt><span class="section"><a href="#id2597438">Motor Retention</a></span></dt><dt><span class="section"><a href="#id2599532">Electronics</a></span></dt><dd><dl><dt><span class="section"><a href="#id2612550">Avionics</a></span></dt><dt><span class="section"><a href="#id2589090">Payload</a></span></dt></dl></dd><dt><span class="section"><a href="#id2581651">Stability Evaluation</a></span></dt><dt><span class="section"><a href="#id2581446">Expected Performance</a></span></dt><dt><span class="section"><a href="#id2599074">Recovery System</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id2592234">3. Construction Details</a></span></dt><dd><dl><dt><span class="section"><a href="#id2599259">Airframe and Couplers</a></span></dt><dt><span class="section"><a href="#id2596433">Fins</a></span></dt><dt><span class="section"><a href="#id2606804">Centering Rings and Bulkheads</a></span></dt><dt><span class="section"><a href="#id2588775">Assembling the Booster Section</a></span></dt><dt><span class="section"><a href="#id2584973">Avionics Bay</a></span></dt><dt><span class="section"><a href="#id2606384">Payload Bay</a></span></dt><dt><span class="section"><a href="#id2607348">Recovery System</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id2600260">4. Recovery Systems Package</a></span></dt><dd><dl><dt><span class="section"><a href="#id2595964">Recovery System Description</a></span></dt><dt><span class="section"><a href="#id2609782">Recovery Initiation Control Components</a></span></dt></dl></dd><dt><span class="chapter"><a href="#id2585586">5. Stability Evaluation</a></span></dt><dt><span class="chapter"><a href="#id2606777">6. Expected Performance</a></span></dt><dt><span class="chapter"><a href="#id2611290">7. Checklists </a></span></dt><dt><span class="chapter"><a href="#id2610811">8. Flight Summary</a></span></dt><dt><span class="chapter"><a href="#id2607490">9. Analysis and Conclusions</a></span></dt></dl></div><p>
- Please note that I stopped adding photos to this document at some
- point. I have many more photos of the YikStik build, but haven't
- decided how best to present them yet... update coming someday!
- </p><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="id2565537"></a>Chapter 1. Introduction</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2565574">Why "YikStik"?</a></span></dt></dl></div><p>
- This is the rocket I'm designing for my NAR Level 3 certification flight.
- The general idea is to build a fairly cheap rocket capable of reliably
- flying this year's Aerotech level 3 special, which is an M1297W reload.
- I'd like to be able to fly the prototype of my own altimeter design, and
- to be able to fly it often on smaller / cheaper reloads at launch sites
- with modest waivers like Hudson Ranch.
- </p><p>
- I want to experiment with vacuum bagging carbon fiber reinforcements, and
- intend to use my CNC milling machine to cut all the centering rings, etc.
- The new Giant Leap "Dynawind" tubing feels like a good choice, and if we
- stick to the 4 inch version we can use a cheap plastic nosecone to keep
- the cost down.
- </p><p>
- Preliminary analysis suggests that a roughly 8 foot rocket made from 4 inch
- airframe with a 75mm mount and three fins should fly to something around
- 14k feet on the M1297W, could break three miles on the M1850W, and yet
- could safely fly on reloads as small as a J for economical fun. Those
- altitudes mean the certification flight will need to be at a site with a
- high-altitude waiver like the NCR north site.
- </p><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2565574"></a>Why "YikStik"?</h2></div></div></div><p>
- I've always thought the high-gloss red paint job on one of my son's rockets
- when out on a launch rod in the sun looks a lot like glistening wet
- lipstick.
- </p><p>
- Combine that with the fact that my wife who isn't fond of the stuff
- refers to lipstick as "yik stick"... and the rest should be obvious.
- </p><p>
- My planned paint scheme is a bright red nosecone, gold tube, and black fin
- can, which is the mental image I have of what lipstick applicators look
- like, most likely from a stick my mother or one of my grandmothers had
- when I was a child.
- </p></div></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="id2557207"></a>Chapter 2. Design</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2557213">Overview</a></span></dt><dt><span class="section"><a href="#id2557231">Rocksim File</a></span></dt><dt><span class="section"><a href="#id2557244">Drawing from Rocksim</a></span></dt><dt><span class="section"><a href="#id2557261">Airframe Tubing</a></span></dt><dt><span class="section"><a href="#id2557277">Nose Cone</a></span></dt><dt><span class="section"><a href="#id2557288">Fins</a></span></dt><dt><span class="section"><a href="#id2608670">Centering Rings and Bulkheads </a></span></dt><dt><span class="section"><a href="#id2597438">Motor Retention</a></span></dt><dt><span class="section"><a href="#id2599532">Electronics</a></span></dt><dd><dl><dt><span class="section"><a href="#id2612550">Avionics</a></span></dt><dt><span class="section"><a href="#id2589090">Payload</a></span></dt></dl></dd><dt><span class="section"><a href="#id2581651">Stability Evaluation</a></span></dt><dt><span class="section"><a href="#id2581446">Expected Performance</a></span></dt><dt><span class="section"><a href="#id2599074">Recovery System</a></span></dt></dl></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2557213"></a>Overview</h2></div></div></div><p>
- YikStik is a fairly simple "three fins and a nose cone" dual-deploy
- rocket using a 75mm motor mount, 4 inch glass-wrapped phenolic airframe
- with zipperless fin can, plastic nose cone, plywood fins,
- and lots of glass and carbon fiber reinforcing.
- The primary electronics bay will be designed to
- hold two altimeters, and a distinct payload bay may carry an
- experimental altimeter, GPS receiver, and downlink transmitter.
- </p></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2557231"></a>Rocksim File</h2></div></div></div>
- This is the current working design in Rocksim format:
- <a class="ulink" href="YikStik.rkt" target="_top"> YikStik.rkt </a></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2557244"></a>Drawing from Rocksim</h2></div></div></div><span class="inlinemediaobject"><img src="YikStik.jpg"></span></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2557261"></a>Airframe Tubing</h2></div></div></div><p>
- I intend to cut the airframe components from two 48 inch lengths of
- 98mm Giant Leap Dynawind tubing. The 30 inch main bay and 18 inch drogue
- bay will be cut from one length, while the 33 inches of fin can, 2 inches
- of electronics bay, and 8 inches of payload bay will be cut from the
- second.
- </p></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2557277"></a>Nose Cone</h2></div></div></div><p>
- I intend to use a Giant Leap "Pinnacle" 3.9 inch nose cone.
- </p></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2557288"></a>Fins</h2></div></div></div><p>
- The fins are designed from scratch, and I intend to build them up from
- two layers of 1/8 inch birch plywood, three layers of carbon fiber, and
- two layers of 6 oz glass. The stack will be glass, carbon fiber,
- plywood, carbon fiber, plywood, carbon fiber, glass. The edges of the
- plywood will be routed to give a modified airfoil shape to the finished
- fins. The stack will be laminated using West Systems epoxy products
- and vacuum bagged.
- The shape is a compromise between mass, surviving Mach-transition stress,
- optimal stability margin, and avoiding damage during handling and on
- contact with the ground during recovery.
- </p><p>
- The fins will be locked in to milled slots in two of the centering rings,
- and will be epoxied to the motor mount with glass reinforcing tape.
- The airframe will be slotted to allow the completed motor mount / fin
- assembly to be inserted from the rear, with fillets of epoxy applied
- inside and outside the airframe after insertion.
- </p></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2608670"></a>Centering Rings and Bulkheads </h2></div></div></div><p>
- All centering rings and bulkheads will be custom machined from 3/8 inch
- birch plywood using my 3-axis CNC milling machine. Some rings will use
- laminated pairs of 3/4 inch total thickness to enable use of threaded
- inserts for 1/4-20 rail button screws or deep routing for fin alignment
- slots.
- </p></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2597438"></a>Motor Retention</h2></div></div></div><p>
- I will embed three 8-24 T-nuts in the aft centering ring spaced to allow
- the use of home-made Kaplow clips to retain 75mm motors.
- The same holes may be used to attach custom motor mount adapters for
- smaller diameter motors.
- </p></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2599532"></a>Electronics</h2></div></div></div><div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2612550"></a>Avionics</h3></div></div></div><p>
- The recovery system will feature dual redundant barometric altimeters
- in an electronics bay similar to the LOC design located between the
- drogue and main parachute bays.
- </p><p>
- A PerfectFlite MAWD will be flown as the primary altimeter and to
- record the flight altitude profile.
- A MissileWorks Mini-RRC2 will fly as backup altimeter and to
- directly capture max velocity.
- </p><p>
- Each altimeter will have a separate battery and power switch. A 4PDT
- slide switch will be used as a SAFE/ARM switch configured to interrupt
- connectivity to the ejection charges.
- </p></div><div class="section" lang="en"><div class="titlepage"><div><div><h3 class="title"><a name="id2589090"></a>Payload</h3></div></div></div><p>
- I hope to fly
- <a class="ulink" href="http://altusmetrum.org/" target="_top">
- my own altimeter design
- </a>
- as a payload in a short payload section just behind the nose cone.
- I have acquired the pieces to add a GPS receiver and RF downlink using
- ham radio frequencies to the payload to track the rocket's position
- during flight.
- This is not essential to fly,
- but could make recovery simpler and would just be fun to fly if I can
- get it all working and suitably ground and/or flight tested in time.
- </p></div></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2581651"></a>Stability Evaluation</h2></div></div></div><p>
- This design has been thoroughly analyzed using
- <a class="ulink" href="http://www.apogeerockets.com/rocksim.asp" target="_top">
- RockSim
- </a>
- with motors ranging from the
- Cesaroni J285 through the Aerotech M1850W and appears to be
- unconditionally stable across that range. The lowest margin is around
- 1.2 seen with the M1297W planned for my level 3 certification flight,
- albeit with many masses still only roughly estimated.
- </p><p>
- These simulations will be refined as the build proceeds and as-built
- stability verified before flight.
- </p></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2581446"></a>Expected Performance</h2></div></div></div><p>
- The Aerotech M1297W reload should carry this vehicle without ballast
- to just over 14 thousand feet AGL. It should make over 16 thousand
- feet AGL on an M1850W, and should fly stably to roughly 2.5k feet AGL
- on a Cesaroni J285.
- </p><p>
- Hitting optimal mass on the largest motors may require
- ballast, depending on final build weight.
- My plan is to fly without ballast on the certification flight,
- trading some altitude for a slower and softer recovery.
- If the cert succeeds, then I might try an optimal mass
- flight sometime later on an M1850W or equivalent "bigger M"
- reload to join the "three mile club".
- </p></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2599074"></a>Recovery System</h2></div></div></div><p>
- The recovery system will use dual redundant barometric altimeters firing
- black powder charges.
- At apogee, a drogue chute will deploy from just forward of the fin can,
- with size selected for an approximately 100 ft/sec descent rate.
- At a preset altitude, a main chute will be deployed to achieve recovery
- of the bulk of the rocket at under 20 ft/sec.
- The main chute will be packed in a deployment bag, configured as a
- "freebag" and pulled out of the airframe by a second drogue chute. This
- drogue will recover the nosecone and deployment bag separately from the
- remainder of the rocket which will recover under the main.
- </p><p>
- I intend to sew the parachutes from scratch using a design documented by
- <a class="ulink" href="http://www.vatsaas.org/rtv/systems/Parachutes/Chute.aspx" target="_top">
- Team Vatsaas
- </a>
- using 1.9oz rip-stop nylon and 550 lb parachute cord.
- If time runs short, equivalent chutes from SkyAngle,
- Rocketman, or Giant Leap could be substituted (at significantly higher
- cost).
- </p><p>
- The deployment bag will probably be purchased from Giant Leap. The
- recovery harness will probably use tubular kevlar, also from Giant Leap.
- </p><p>
- The recovery system attachment points will all use 1/4 inch u-bolts with
- nuts, washers, and backing plates through bulkheads except for the fin
- can. The fin can has insufficient room between the motor mount and
- the airframe inner wall for nuts and washers, so an alternative means of
- recovery system attachment is required. The fin can will be equipped
- with either a 3/16 inch stainless steel aircraft cable loop, or a loop
- of 1/2 inch tubular kevlar, bonded to the motor mount.
- If available, a screw-eye attached to the forward motor closure may be
- used instead of or in addition to this recovery attachment loop.
- </p></div></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="id2592234"></a>Chapter 3. Construction Details</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2599259">Airframe and Couplers</a></span></dt><dt><span class="section"><a href="#id2596433">Fins</a></span></dt><dt><span class="section"><a href="#id2606804">Centering Rings and Bulkheads</a></span></dt><dt><span class="section"><a href="#id2588775">Assembling the Booster Section</a></span></dt><dt><span class="section"><a href="#id2584973">Avionics Bay</a></span></dt><dt><span class="section"><a href="#id2606384">Payload Bay</a></span></dt><dt><span class="section"><a href="#id2607348">Recovery System</a></span></dt></dl></div><p>
- I have collected all of my
- <a class="ulink" href="http://gallery.gag.com/rockets/yikstik" target="_top">
- build photos
- </a>
- in one place, they may show better than I can explain how various
- aspects of YikStik went together.
- </p><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2599259"></a>Airframe and Couplers</h2></div></div></div><p>
- The tubing for the airframe, couplers, and motor mount was all cut
- using a carefully aligned and adjusted power mitre saw, and the ends
- lightly sanded to remove rough spots.
- The main and drogue bays were cut from one 48 inch length of Giant
- Leap 98mm Dynawind tubing, the fin can, electronics bay, and payload
- bay were cut from the second. The three couplers for the fin can,
- electronics bay, and payload bay were cut from Giant Leap 98mm phenolic
- coupler stock. And the motor mount was cut from Giant Leap 75mm
- phenolic airframe stock.
- Note that the motor mount is the longest piece because of
- the zipperless design with full-length motor mount.
- </p><p>
- The airframe tubing selected includes a wrap of 10oz glass in epoxy
- over the base phenolic tubing (visible in some photos as a
- shine on the outside of the tubing),
- but the coupler stock is unreinforced.
- To ensure the couplers can handle the anticipated loading, I reinforced
- each with one layer of interior carbon fiber, using the "kitchen
- vacuum bagging" technique documented by
- <a class="ulink" href="http://www.jcrocket.com/kitchenbagging.shtml" target="_top">
- John Coker.
- </a>
- </p><p>
- This was my first hands-on experience working with carbon fiber. The
- end of the coupler nearest the unit during bagging experienced some
- crushing of the fibers right at the end. It doesn't matter for this
- project because each of the couplers will have at least one end fitted
- with a bulkhead or centering ring, but in the future I'll be tempted
- to cut the coupler stock a bit long before bagging and trim to length
- after reinforcing to get "perfect" ends. The technique worked
- marvelously otherwise, and the resulting couplers look and should work
- great!
- </p></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2596433"></a>Fins</h2></div></div></div><p>
- Six pieces of 1/8 inch birch plywood were stacked, edge-aligned on what
- would be the fin root edge, and clamped. The outline of the fin design
- was marked in pencil, and three 1/8 inch holes drilled through the
- stack inside the fins to allow using 4-40 screws and nuts to hold the
- blanks together while making the initial cuts, so that they would all be
- matched in size. The clamps were removed to avoid interference
- during cutting. The fin outline was then cut using a radial arm saw.
- </p><p>
- A router table with 1/8 inch
- roundover bit was then used to round over the outer edge, 3 blanks on
- one side and three on the other. This edge might have been left square,
- but I prefer the look and feel of rounding. The router table with a 1/2
- inch diameter straight cutting bit and a fin beveling jig was used
- to impart a 10-degree bevel on the leading and trailing edge of each fin
- blank, again 3 on one side and three on the other. The resulting 6
- blanks thus form 3 pairs of fin components with a modified
- airfoil shape.
- </p><p>
- The fin assembly started with a simple lamination of two layers of ply
- sandwiching a layer of carbon fiber. Each fin used "one pump" of West
- Systems epoxy and the stack was vacuum bagged using the Foodsaver with
- wide bagging material. To keep everything flat while the epoxy cured,
- the stack of fins was sandwiched between two unused extra shelves for
- a storage cabinet I had on hand
- (particle board covered in laminate, very
- flat and smooth, nearly inflexible at this loading), and stacked with
- about 75 lbs of loose barbell weights.
- </p><p>
- On one of the three fins, the plywood layers are out of alignment by
- 1-2mm in the longest axis. The other two are nearly perfect. Light
- sanding should allow me to match them before laminating the outer layers
- of carbon fiber and glass.
- </p><p>
- After the fins cured, they were bulk sanded with medium and fine
- sandpaper and an electric palm sander. Final sanding of the leading
- and trailing edges was done using 400 grit paper on a flat surface,
- holding the fin the way you'd sharpen a knife against a stone. The
- results seem good, all three fins match pretty closely.
- </p><p>
- A fin holding jig was cut from 1/8" hardboard using my rotary tool
- with a fiber cutoff wheel. The fin slots were made to be a snug fit.
- A small batch of epoxy was used to apply a bead to the root edge and
- tab at the leading edge, then the fins were installed against the
- motor mount and locked into place with the jig to cure. The centering
- ring that locks the aft edge of the fins was dry-fit during this
- operation to ensure proper alignment, but was not glued yet. It will
- go on after the airframe and internal fin filets are installed.
- </p><p>
- The fins were reinforced with fiberglass and epoxy. Masking tape was
- used to carefully delineate where the airframe ID will be, then 6oz
- glass 14.25" by 3.5" was epoxied fin-fin across the MMT. Strips of
- 8.6oz "boat tape" fiberglass were worked into the joints with more
- epoxy, and a sheet of plastic covered by ziplog bags of water were
- used to hold things in place during the initial curing. The three
- sides were done one at a time and allowed to cure before proceeding.
- The results look good, and in combination with internal and external
- airframe filets should yield a super-strong fin can.
- </p></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2606804"></a>Centering Rings and Bulkheads</h2></div></div></div><p>
- Pairs of 3/8 inch birch plywood blanks were laminated using Titebond
- wood glue and clamped while curing to form 3/4 inch blanks for centering
- rings. From a strength perspective, 3/8 inch should suffice, but there
- are two reasons for going with thicker blanks in some places. The first
- is that the rail buttons chosen use 1/4-20 mounting screws, and threaded
- inserts in that size are nearly 3/8 inch outside diameter
- (and thus would
- tear up a ring only 3/8 inch thick on insertion). The second is that I
- like to mill slots in the centering rings on each end of the fins to
- "lock" the fins into position. Doubling the blanks used to cut those
- rings will allow me to cut 1/4 inch deep fin slots and still have a half
- inch of unmolested wood in the rings for strength.
- </p><p>
- The aft centering ring and the one just aft of the zipperless
- coupler section were edge-drilled for the installation of brass
- 1/4-20 threaded inserts to hold rail buttons. The inserts were
- locked in place with epoxy, then ground down until nothing protruded
- beyond the OD of the ring.
- </p></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2588775"></a>Assembling the Booster Section</h2></div></div></div><p>
- The forward two centering rings were installed on the MMT using
- JB Weld high-temperature epoxy, and incorporating an aircraft cable
- loop for recovery system retention since there just wasn't room for
- u-bolts.
- </p><p>
- The ring at the leading edge of the fins was initially installed
- assuming the aft ring would be nearly flush with the rear of the MMT
- and equipped with Kaplow-clip style retainers, but before the fins
- were installed a Giant Leap Slimline Tailcone Retainer for 75mm motor
- in 98mm airframe became available thanks to Tim Thomas, and so this
- ring was cut out and replaced with another one inch farther forward
- to allow installation of the tailcone at the rear of the MMT. I
- really like the tailcone on my Vertical Assault kit, and think it'll
- work out to be a great addition for this rocket!
- </p><p>
- An alignment jig for the fins was carefully marked out and then cut
- from 1/8 inch hardboard using my rotary tool and abrasive cutoff wheel.
- The fins were then epoxied at the root and short leading edge to the
- motor mount tube and into the slots in the forward centering ring,
- and held rigidly aligned by the jig until the epoxy set. The fins
- were then masked at what would be the ID of the airframe tube, and
- reinforced with 6oz glass fin-fin across the motor mount tube between
- each fin pair, further reinforced with strips of 1 inch glass "boat
- tape" at each fin root joint.
- </p><p>
- The airframe tubing section was carefully marked for fin slots, which
- were then cut using my rotary tool with abrasive cutoff wheel. Epoxy
- was applied ahead of the center two rings as the frame was slid into
- place, and the frame left standing upright until the epoxy set to
- hopefully form ring-fin fillets on those two rings. The interior
- fin to airframe joints were reinforced one fin at a time using West
- Systems epoxy will milled glass as a filler. A long 3/8" dowel was
- used to place and smooth these interior filets. The aft centering ring
- was installed by pouring West Systems epoxy in the three fin-fin gaps,
- placing the ring, then standing the airframe up to allow the epoxy to
- flow over the forward surface of the ring and into the gaps between it,
- the motor mount, and the airframe tubing. After it set, the booster
- was placed nose-down, the airframe gaps behind the fins were taped,
- and more epoxy was applied to seal the aft of the ring to the tubes.
- Before this epoxy set, JB Weld was used to glue the tail cone retainer
- in place on the MMT.
- </p><p>
- The exterior fin to
- airframe joints were filleted using 5-minute epoxy thickened with
- baby powder and smoothed with the tip of a plastic spoon, which I
- learned about building the Vertical Assault kit. Gives great results,
- and allowed all 6 joints to be done in one session. The space
- above the top surface of the forward centering ring and between the
- motor mount and zipperless-design coupler tubing was filled with epoxy
- and milled glass. Minor gaps in the airframe behind each fin were
- filled with epoxy clay.
- </p></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2584973"></a>Avionics Bay</h2></div></div></div><p>
- The avionics bay contains the two commercial altimeters used to
- record information about the flight and deploy the drogue and main
- recovery systems. It is constructed of a piece of Giant Leap 98mm
- coupler tubing reinforced with an interior wrap of vacuum-bagged
- carbon fiber, and a 2 inch length of Giant Leap 98mm DynaWind airframe
- tubing.
- </p><p>
- The bulkheads are custom-milled from 3/8 inch birch plywood
- milled so that about 3/16" fits inside the coupler and the remainder
- seals the end of the coupler and just fits inside the airframe. Each
- bulkhead has a u-bolt for attaching the recovery harnesses, and dual
- CPVC end caps as ejection charge holders with screw terminal blocks
- from Missile Works to attach the igniters. Two lengths of 1/4 inch
- all-thread with nuts and washers tie the bulkheads together, with
- wing-nuts used on one end to allow for easy disassembly.
- </p><p>
- A sled was fabricated to hold the altimeters and batteries. It
- consists of 1/8 inch birch ply laminated with 6oz fiberglass on each
- side, epoxied to cardboard tubes taken from the packaging for Aerotech
- igniters that slide over the all-thread, further reinforced with nylon
- ties at each end. The tubes are staggered one on either side so that
- the sled goes right up the center of the airframe tubing.
- </p><p>
- Two "centering rings" containing three each 6-32 threaded inserts are
- epoxied inside the bay to provide hard points for attaching the
- airframe tubes for the drogue and main recovery bays. The inside
- diameter of these rings is notched for the avionics sled, and thus
- these rings also provide physical support for the sled.
- </p><p>
- Three rotary switches from Missile Works are installed through the
- short airframe tubing section, drilled such that they end up
- essentially flush with the outside of the airframe, clamp the coupler
- tubing, and project inside the bay. Two are wired as SPST switches
- for power to the two altimeters, the third is wired as a DPST switch
- that open-circuits the igniters for the required "safe/arm" function
- called for in the NAR L3 certification requirements.
- </p><p>
- The wiring of the avionics bay is documented in the attached
- schematic diagram. Connectors were used to allow each bulkhead and
- the switches in the housing to be quickly detached from the sled.
- The connectors are 9-pin D shells for the switch wiring, and 4-pin
- Molex connectors like those used on older PC hard drive power cables
- for the bulkheads. To allow use of a single switch pole for the
- safe/arm function for each altimeter, the two igniters attached to
- each altimeter are safed by interrupting the common return lines as
- shown in the schematic.
- </p><p>
- Sizing the static port for the avionics bay was done by applying the
- formulas suggested by PerfectFlite and Missile Works for their
- respective altimeter products, then comparing the results with each
- other and with information found on the web. I've personally had
- better luck with single ports than with multiple holes, perhaps because
- I've been working with relatively small rockets. Regardless, I'm
- sticking with what I know and will use a single static port hole here.
- </p><p>
- The measured dimensions
- of the avionics bay as constructed are 95mm ID and approximately 250mm
- between bulkheads. This works out to 108.73 cubic inches before
- accounting for the volume of the sled, electronics, and wiring and
- other components inside the bay. By the PerfectFlight formula, the
- static port should be 0.221 inches in diameter. By the Missile Works
- formula for a bay over 100 cubic inches the answer is 0.261 inches.
- The closest standard drill size, which happens to split the difference,
- is 0.250 inches. Easy enough!
- </p></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2606384"></a>Payload Bay</h2></div></div></div><p>
- The construction of the payload bay is very similar to the avionics
- bay, except that there is a hard-epoxied rear bulkhead, and only one
- screw ring to hard-mount the nose cone. The forward end of the
- payload bay is open to the open interior volume of the nose cone in
- anticipation of extending downlink antennas above the carbon fiber
- reinforcement in the coupler and into the nose cone, since carbon
- fiber is opaque to RF.
- </p></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2607348"></a>Recovery System</h2></div></div></div><p>
- Pre-sewn 1/4 inch tubular kevlar harness sections were purchased
- from Giant Leap, along with a small kevlar deployment bag and two
- kevlar chute protectors.
- </p><p>
- For an apogee drogue, I plan to fly a Public Missiles 4 x 144 inch
- nylon streamer. It will be protected with one of the kevlar blankets
- and attached to one of the kevlar harness sections holding the booster
- to the avionics bay.
- </p><p>
- The main parachute will be sewn from 1.9 oz rip-stop nylon purchased
- from the
- <a class="ulink" href="http://www.milloutletfabric.com/" target="_top">
- Mill Outlet Fabric Shop
- </a>
- in Colorado Springs. Using the spreadsheet from
- <a class="ulink" href="http://www.vatsaas.org/rtv/systems/Parachutes/Chute.aspx" target="_top">
- Team Vatsaas
- </a>
- I calculate that we want an 8 foot chute to keep the airframe less
- nose cone and payload bay below 20 feet per second at touch-down.
- </p><p>
- To extract the main chute and recover the nose cone and payload bay,
- a 3 foot parachute from BSD Rocketry will be packed in a kevlar
- blanket ahead of the main chute deployment bag, attached by kevlar
- harness to the nose cone and payload bay assembly, and to the top of
- the deployment bag. This assembly will recover separately from the
- rest of the rocket.
- </p><p>
- The altimeters are programmed such that the MAWD fires its drogue
- charge at apogee and its main charge at 1100 feet. The miniRRC2
- is programmed to fire its drogue charge two seconds past apogee,
- and its main charge at 900 feet. Thus the MAWD is primary and the
- miniRRC2 is the backup. Since the M1297W has a burn time of about
- 5 seconds, mach inhibit is programmed on both altimeters to 8 seconds.
- </p></div></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="id2600260"></a>Chapter 4. Recovery Systems Package</h2></div></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#id2595964">Recovery System Description</a></span></dt><dt><span class="section"><a href="#id2609782">Recovery Initiation Control Components</a></span></dt></dl></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2595964"></a>Recovery System Description</h2></div></div></div><p>
- This rocket uses dual deployment.
- </p><p>
- The apogee event separates the
- airframe between the zipperless-design booster section and the
- drogue bay. These two sections are linked by a Giant Leap 20 foot
- pre-sewn 1/4 inch tubular kevlar assembly, attached to which is a
- Public Missiles 4 x 144 inch red nylon streamer packed in a Giant Leap
- kevlar chute protection pad.
- </p><p>
- The main event separates the airframe between the forward payload bay
- and the main bay. Attached to the nose cone and payload bay assembly
- is a Giant Leap 15 foot pre-sewn 1/4 inch tubular kevlar assembly,
- attached "free bag" style to the top of a Giant Leap deployment bag
- containing the main chute. A 36 inch BSD Rocketry nylon parachute
- packed in a Giant Leap kevlar chute protection pad serves to pull the
- deployment bag off the main chute, after which it allows for safe
- recovery of the nose cone and payload assembly at just under 20 feet
- per second.
- </p><p>
- The 8 foot main chute is home-made from 1.9 oz rip-stop nylon using
- the design documented by
- <a class="ulink" href="http://www.vatsaas.org/rtv/systems/Parachutes/Chute.aspx" target="_top">
- Team Vatsaas.
- </a>
- It is attached to the remainder of the rocket using another Giant Leap
- pre-sewn 1/4 inch tubular kevlar assembly.
- </p><p>
- The anchor points are all 5/16 inch u-bolts, except for on the booster
- which is equipped with an embedded loop of 3/16 inch stainless aircraft
- cable. All connections are made with suitable quick-links.
- </p></div><div class="section" lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="id2609782"></a>Recovery Initiation Control Components</h2></div></div></div><p>
- The LOC-style avionics bay between the main and drogue bays is
- populated with two commercial altimeters, a PerfectFlite MAWD
- and a Missile Works miniRRC2.
- Each is powered by a dedicated 9V battery, and has a
- dedicated on/off power switch mounted for access from outside the
- rocket. Additionally, a single safe/arm switch with two poles is used
- to interrupt the return circuits from the igniters to each altimeter.
- See the attached schematic of the avionics bay contents for more
- details.
- </p><p>
- The bulkheads at each end of the avionics bay have two CPVC end caps
- for ejection charge holders, and two-terminal screw blocks for
- attachment of electric matches purchase from Giant Leap used to ignite
- Goex 4F black powder ejection charges. Each charge holder and terminal
- block pair is labelled as to main or backup since the charges will be
- different for each.
- </p><p>
- The
- <a class="ulink" href="http://www.info-central.org/recovery_powder.shtml" target="_top">
- Info Central Black Powder Sizing
- </a>
- page is the most authoritative site I've found on this topic.
- Each of the main and drogue bay interfaces will use 2 2-56 nylon screws
- as shear pins, each of which needs 35 pounds of force or so to shear.
- Designing for 15psi puts us between 150 and 200 pounds total force in
- a 4 inch airframe. The formula is thus 0.006 grams times diameter
- squared in inches times length in inches.
- </p><p>
- My drogue bay is 3.9 inches ID and 8 inches long, or 95.52 cubic
- inches. That works out to about 0.73 grams. However, there will be
- some volume in the motor mount tube above the motor that also must
- be accounted for, enough to nearly double the total volume when flying
- on the M1297W certification motor. Also, since this charge must fire
- reliably at 15-18k feet above ground level of around 5k feet, such
- that combustion is likely to be incomplete, we need to add some margin.
- </p><p>
- My main bay is 3.9 inches ID and about 25 inches between bulkheads,
- or about 298.50 cubic inches. That works out to 2.28 grams.
- </p><p>
- Sanity checking, PerfectFlite recommends that a 4F black powder charge
- be sized by multiplying the volume of the bay in cubic inches by 0.01
- grams. That yields about 1.8 grams for the drogue bay and 3 grams for
- the main bay.
- </p><p>
- That suggested to me that a good starting point for ground testing is
- 1.5 grams for the drogue bay and 2.5 grams for the main bay. Ground
- tests were done using the PC interface cable for the MAWD routed in
- through the static test port to manually trigger ejections. Testing
- of the apogee bay showed that 1.5 grams was sufficient for deployment
- and 1.8 grams was more authoritative. A single test of main deploy
- with 2.5 grams gave a nearly perfect result.
- Given the altitude of our expected apogee, we should be generous with
- the apogee charge, perhaps using 2.0 grams for the primary. The main
- will deploy at an altitude below where the tests were performed, so
- no adjustment in charge size should be required.
- </p><p>
- Descent rate of the nose cone and payload bay which mass just under
- 1kg will be less than 20 feet per second with a 36 inch chute based
- on manufacturer recommendations and Rocksim v8 simulation.
- Descent rate of the remainder of the rocket under the 8 foot chute
- should be about 18 feet per second by the spreadsheet provided by
- the designers of this chute pattern, sanity checked using the descent
- rate tables of similar commercial parachute designs, like those from
- The Rocketman.
- </p></div></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="id2585586"></a>Chapter 5. Stability Evaluation</h2></div></div></div><p>
- Simulation using Rocksim v8 with a variety of motors showed that the
- rocket is unconditionally stable with all motors likely to be flown.
- The worst-case stability among 75mm motors is actually with the
- M1297W chosen for the certification flight, at margin 1.05. This is
- because the front of this motor falls almost exactly at the CP. Using
- a longer motor like the M1850W raises the initial stability margin to
- 1.10 because the front fuel grain is ahead of the CP, and lesser
- motors also increase the stability because less mass is behind the CP.
- The smallest motor I can conceive of flying in this rocket (a Cesaroni
- J285) would leave us overstable with margin 3.79 on the way to about
- 1800 feet apogee.
- </p></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="id2606777"></a>Chapter 6. Expected Performance</h2></div></div></div><p>
- On the certification flight, using an Aerotech M1297W reload and
- associated hardware, the anticipated apogee is round 14,700 feet. This
- is just under 75% of the NCR North Site standing waiver of 20,000 feet.
- </p><p>
- The highest altitude simulated would be achieved with an Aerotech
- M1850W reload at nearly 18,000 feet. The lowest altitude simulated
- is with a Cesaroni J285 and Slimline adapters to just over 1800 feet.
- </p><p>
- add description of anticipated flight profile here, including launch
- weight, estimated drag coefficient, velocity leaving the rail, max
- expected velocity, altitude, and acceleration
- </p></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="id2611290"></a>Chapter 7. Checklists </h2></div></div></div><div class="orderedlist"><ol type="1"><li>
- Planning
- <div class="orderedlist"><ol type="1"><li>
- Pick a club launch with suitable waiver and facilities to
- support flight.
- </li><li>
- Confirm L3CC member(s) available to attend selected launch.
- </li><li>
- Confirm that required loaner motor hardware will be available at launch.
- </li><li>
- Notify launch sponsor (club president) of intended flight.
- </li><li>
- Notify interested friends of intended flight.
- </li><li>
- Perform final pre-flight simulation with as-built masses, etc.
- </li><li>
- Gather consummables and tools required to support flight
- <div class="orderedlist"><ol type="1"><li>
- fresh 9V batteries
- </li><li>
- black powder
- </li><li>
- e-matches
- </li><li>
- motor retainer snap rings
- </li><li>
- small nylon wire ties
- </li><li>
- cellulose wadding material
- </li><li>
- masking tape
- </li><li>
- screwdriver for phillips-head airframe screws
- </li><li>
- small straight-blade screwdriver for power switches
- </li><li>
- motor reload kit
- </li><li>
- high temperature grease
- </li><li>
- long small diameter dowels for igniter insertion
- </li></ol></div></li></ol></div></li><li>
- Before Leaving Home
- <div class="orderedlist"><ol type="1"><li>
- program altimeters for suitable mach delay and recovery deployment
- <div class="itemizedlist"><ul type="disc"><li>
- MAWD
- <div class="itemizedlist"><ul type="circle"><li>
- 8 seconds mach delay
- </li><li>
- 1500 foot main deploy
- </li></ul></div></li><li>
-
- miniRRC2
- <div class="itemizedlist"><ul type="circle"><li>
- 8 seconds mach delay
- </li><li>
- 1000 foot main deploy
- </li><li>
- 2 seconds apogee delay
- </li><li>
- no main delay
- </li><li>
- dual deploy
- </li><li>
- ops mode 16 (default)
- </li></ul></div></li></ul></div></li><li>
- assemble all recovery system components and ensure everything fits
- </li><li>
- confirm wiring and operation of altimeter power and safe/arm switches
- </li><li>
- Ground test recovery system to confirm suitable black powder
- charge sizing
- </li></ol></div></li><li>
- Pre-Flight
- <div class="orderedlist"><ol type="1"><li>
- confirm payload batteries in good condition, bay loaded, power switch works
- </li><li>
- confirm reception of signals from transmitter(s) in payload bay
- </li><li>
- install fresh 9V batteries for altimeters on avionics bay sled
- </li><li>
- inspect altimeters and associated avionics bay wiring for visible faults
- </li><li>
- close up avionics bay
- </li><li>
- install e-matches, confirming resistance of 1-2 ohms and fit in charge cups
- </li><li>
- power up altimeters, operate safe/arm switch, and confirm e-match continuity
- </li><li>
- load BP charges into charge cups
- <div class="orderedlist"><ol type="1"><li>
- Drogue Primary Charge - 2.0 grams 4F BP
- </li><li>
- Drogue Backup Charge - 2.5 grams 4F BP
- </li><li>
- Main Primary Charge - 2.5 grams 4F BP
- </li><li>
- Main Backup Charge - 3.0 grams 4F BP
- </li></ol></div></li><li>
- connect recovery harnesses and install recovery bay airframe sections
- </li><li>
- power up altimeters, operate safe/arm switch, and confirm e-match continuity
- </li><li>
- safe and power-down the altimeters
- </li><li>
- load main recovery bay, attaching nosecone and payload bay assembly
- </li><li>
- install nylon 2-56 screws as shear pins between main bay and payload bay
- </li><li>
- load drogue recovery bay, feeding harness end through fin can motor tube
- </li><li>
- install nylon 2-56 screws as shear pins between drogue bay and fin can
- </li><li>
- load motor per manufacturer instructions
- </li><li>
- attach forged eye-bolt to forward closure if not already present
- </li><li>
- attach drogue harness to eye-bolt on forward motor closure
- </li><li>
- install motor in motor mount
- </li><li>
- install motor retention snap rings
- </li><li>
- prepare igniter for later installation by attaching to long 1/8" dowel
- </li><li>
- confirm all screws in place, avionics off and safe
- </li><li>
- fill out a launch card
- </li><li>
- notify RSO/LCO of readiness for inspection and launch, obtain a rail
- assignment and permission to move rocket to launch pad for final prep
- </li><li>
- coordinate readiness with support team members, photographers, observers
- </li></ol></div></li><li>
- Final Prep
- <div class="orderedlist"><ol type="1"><li>
- move rocket to launch area
- </li><li>
- clean and lubricate launch rail if necessary
- </li><li>
- power up payload and confirm reception of signals from transmitter(s)
- </li><li>
- mount rocket on launch rail, rotate to vertical
- </li><li>
- power up primary altimeter, confirm expected beep pattern
- </li><li>
- power up backup altimeter, confirm expected beep pattern
- </li><li>
- arm ejection charges
- </li><li>
- confirm altimeters both giving expected beep patterns for igniter continuity
- </li><li>
- install igniter and connect to launch control system
- </li><li>
- capture GPS waypoint for rail location
- </li><li>
- smile for the cameras, make sure we have enough "foil Murphy!" shots taken
- </li><li>
- retreat to safe area behind LCO
- </li><li>
- confirm continued reception of transmitter signal(s) from payload bay
- </li><li>
- confirm photographers and observers are ready and know what to expect
- </li><li>
- make sure binoculars and backpack with water and recovery tools are at hand
- </li><li>
- tell RSO and LCO we're ready to launch
- </li><li>
- try to relax and enjoy watching the flight!
- </li></ol></div></li><li>
- Recovery
- <div class="orderedlist"><ol type="1"><li>
- track rocket to landing site
- </li><li>
- capture GPS waypoint of landing site, take lots of photos
- </li><li>
- note any damage
- </li><li>
- gather up and roughly re-pack recovery system for return to flight line
- </li><li>
- bring the rocket to observers for post-flight inspection
- </li></ol></div></li></ol></div></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="id2610811"></a>Chapter 8. Flight Summary</h2></div></div></div><p>
- YikStik was flown on an M1297W on Saturday morning at NCR's Oktoberfest
- 2008. The boost was beautiful. Unfortunately, we lost visual as the
- rocket climbed into high clouds near apogee. Radio tracking signals
- remained strong for several minutes, then disappeared. We were
- confused by viewing what we thought was YikStik descending before
- signals were lost in about the right direction, but now believe we
- were actually watching a previously launched rocket and did not see
- YikStik descend. This confusion prevented location of any of the
- rocket until Sunday evening, after I had left the launch area.
- </p><p>
- After an extensive search, the nose cone assembly was finally found
- with the Walston tracking gear nearly 3.5 miles down range. The
- remainder of the rocket has not been found despite extensive searching
- on the ground and from the air.
- </p><p>
- Reward if returned posters were placed in the area during the week
- following the launch but have elicited no useful reponses yet.
- </p></div><div class="chapter" lang="en"><div class="titlepage"><div><div><h2 class="title"><a name="id2607490"></a>Chapter 9. Analysis and Conclusions</h2></div></div></div><p>
- Consideration of how the nose cone ended up where it did suggests
- we may have had an apogee deployment of the main, perhaps due to
- stress on the shear pins before launch, during boost, or during
- apogee drogue deployment causing them to break early.
- </p><p>
- It is unfortunate that we were confused by seeing another rocket
- descending about the expected amount of time after YikStik's launch
- in approximately the right direction. This caused us to believe that
- the rocket was much closer than the nose cone turned out to be, causing
- us to waste a lot of time searching in an area too close to the launch
- site.
- It also caused us to assume something really weird had happened to the
- transmitters, such that the tracking signal was suddenly lost long
- after the rocket was on the ground, instead of what seems to really
- have happened, which is that the rocket was farther away descending
- after a main deployment at apogee, and the loss of signal was simply
- due to dropping below a ridge line a couple miles from the launch site.
- I can't help but think that if we'd been
- looking in the right area sooner after the launch that we might have
- found the rocket before someone else apparently picked it up.
- </p><p>
- I regret the decision to use a "free bag" configuration of the
- deployment bag.
- Since both tracking transmitters were in the payload bay behind
- the nose cone, and we were eventually able to recover that portion
- of the rocket, it is possible that if the deployment bag were tethered
- to the main that we might have recovered the remainder of the rocket.
- </p><p>
- If the rocket is recovered and able to fly again, the two changes I
- would like to make are to tether the deployment bag to the apex of the
- main, and to move from 2-56 nylon screws to 4-40 nylon screws for the
- main deployment shear pins, ensuring the holes through the airframe
- are a loose enough fit to avoid stresses on the pins during boost. I
- have no way to know what happened for sure, but believe this might
- solve the assumed problem of main deployment at apogee.
- </p><p>
- All in all, the design and build process was educational, and a lot
- of fun! I'm looking forward to fabricating more custom parts using
- carbon fiber and vacuum bagging in the future.
- The beautiful boost and obvious survival of the rocket airframe
- through the expected mach transitions confirms my design and
- construction skills are adequate to attain an L3 cert.
- While I hope to recover the remainder of YikStik someday, I won't
- waste any time before trying again with a new airframe!
- </p><p>
- [update] We have learned that one of the altimeters used in this
- flight, the Missile Works miniRRC2, was subject to a fault in
- firmware that could cause premature ejection of the main
- in flights above 10k feet. Thus, it now seems even more likely
- that we sustained an apogee ejection of the main, but that it
- may well have been through no fault of the rocket's design,
- construction, or preparation. Frustrating!
- </p></div></div></body></html>
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