5 This is a "replacement" for Bdale's first L3 certification airframe,
6 [YikStik](../YikStik), which was mostly lost... and a follow-on to
7 [2YikStik](../2YikStik), which had one and only one "way too exciting"
8 flight at LDRS 30. We recovered the nose cone, tail cone, rail buttons,
9 and all of the electronics from 2YikStik. Everything else is new for this
12 Robert is very interested in measuring the temperature of a nose
13 cone and a fin on a rocket at speeds above Mach. This led Bdale to design
14 a [TeleMetrum](http://altusmetrum.org/TeleMetrum) companion board called
15 [TeleScience](http://altusmetrum.org/TeleScience) capable of hosting up to
16 12 NTC thermistors for temperature data collection. As was the case with
17 [2YikStik](../2YikStik), the plan is to fly two
18 [TeleMetrum](http://altusmetrum.org/TeleMetrum)+[TeleScience](http://altusmetrum.org/TeleScience)
19 setups, one mounted in the nose cone and one mounted in the fin can. The
20 one in the fin can will be responsible for apogee deployment, and the one in
21 the nose cone will handle main deployment.
23 We will again fly a custom 98mm nose cone with the temperature sensors
24 embedded in the glass layers made for us by Jeff Lane of
25 [Shock Wave Rocketry](http://shockwaverocketry.com/).
29 * 98mm [Performance Rocketry](http://performancerocketry.com) G-10 convolute glass air frame
30 * 98mm [Performance Rocketry](http://performancerocketry.com) G-12 filament-wound glass couplers
31 * 75mm [PML](http://www.publicmissiles.com) phenolic motor mount
32 * [Shock Wave Rocketry](http://shockwaverocketry.com/) fiberglass 98mm Von Karman 6:1 nose cone
33 * custom fins, using 3/16 inch birch plywood laminated with carbon fiber
34 and a fibreglass sanding veil
35 * 3/8 inch birch plywood centering rings and bulkheads, CNC milled, the two
36 that hold the fins are double thickness (3/4 inch) and notched for perfect
39 The OpenRocket design file is
40 [YikStik3.ork](/rockets/airframes/YikStik3/YikStik3.ork).
44 The temperature sensors chosen are 0.8 mm diameter glass bead NTC thermistors
45 made by EPCOS, model B57540G0303F000. These were chosen because of their
46 small size, and turn out to have a very fast response time to changing
49 The leads were extended with 30 gauge wire wrap wire using twisted pairs of
50 black plus a color. The colored lead was insulated from the bead back over
51 the solder joint using 1/16 inch heat shrink tubing. The epoxy used for the
52 nose cone and fin was tested and confirmed to have essentially no
57 The airframe geometry led us to decide to build two electronics bays, one in
58 the airframe immediately aft of the nose cone, and the other in the fin can.
59 Each bay holds a production
60 [TeleMetrum](http://altusmetrum.org/TeleMetrum), a prototype companion
61 board called [TeleScience](http://altusmetrum.org/TeleScience), a 1000 mAh
62 LiPo battery, and a power switch.
64 The prototype TeleScience boards support connection of up to 12 NTC thermistors along
65 with other capabilities.
67 Installing the electronics in the fin can bay was a *huge* challenge due to the
68 restricted space between the MMT and airframe. All of the through-hole connectors on
69 both boards were removed, along with the GPS antenna and beeper on the TeleMetrum board,
70 yielding two boards with no parts on the "top" side. A short piece of ribbon cable was
71 hard-wired between the companion ports on the two boards, and the LiPo battery leads
72 were soldered to TeleMetrum. The TeleMetrum board was equipped with an edge-launched
73 SMC RF connector (smaller in diameter than an SMA) for attachment to an off-board
74 antenna. Then the boards were installed on minimum-height standoffs above the phenolic
75 motor mount behind a hatch cut in the airframe between two fins, with the GPS antenna
76 and beeper epoxied down to the side of the TeleMetrum board. The battery was mounted
77 as far forward as possible and blocked in with some small bits of scrap balsa stuck down
78 with super glue. The power switch was mounted near the aft end of the bay such that a
79 small screwdriver reaching through the 0.25 inch static vent can be used to turn things
84 On 2YikStik, one of the big disappointments was a very poor signal from the
85 UHF transmitter on the TeleMetrum board mounted in the fin can. This isn't
86 surprising, since the antenna was just a wire whip running in parallel with
87 and very close to the motor casing. For this build, I decided to try
88 something completely different.
90 The quick summary is that I'm loading up the two fins that don't have thermistors
91 in them as an antenna. And it works brilliantly!
93 Before bagging the fins with the CF and glass lamination, I put 1 inch wide
94 copper foil tape on two of the fin substrates, running from near the tip
95 down to the root. Then the fins were bagged with 2 layers of 5.7 oz 2x2
96 twill carbon fiber and a 6 oz glass sanding veil layer on both sides, all in
97 one bagging operation to ensure all the layers formed a strong chemical epoxy
100 After unbagging, while the epoxy was still somewhat leathery, I carefully
101 cut the CF back at the root edge of each fin exposing the copper foil. The
102 fins were then allowed to cure and get sanded normally. When installing them
103 in the airframe, I oriented them so that the thermistor fin is on the anti-rail
104 side of the airframe, and the two copper-foil-equipped fins bracket the rail
105 side, with the copper foil sides facing each other across the rail-side valley.
107 After applying fin to fin glass across the motor mount, additional copper foil
108 tape was used to join the two fins, soldering the new foil to the foil embedded
109 in the fins. I then cut a "gap" in the center of the space between the two
110 fins, and installed a 1.5-20pF piston trimmer capacitor with the screw aimed
111 aft, and a piece of small diameter teflon coax with two ferrite beads on the
112 forward side of the gap. The coax was run through a hole near the root of
113 the fin separating this valley from the ebay and terminated with an SMC
114 connector to mate with the TeleMetrum board.
116 I'm pleasantly surprised at how well this seems to work. With a Pro75 6xl
117 case installed, the variable cap allows the antenna to be tuned to about 1.3:1
118 SWR, and the resulting transmitted signal seems strong...
122 Parts gathered during late 2011 and early 2012. Built starting in early
123 March of 2012, and completed in time for [NCR](http://www.ncrocketry.org/)'s
124 Mile High Mayhem 2012.
126 The nose cone was custom fabricated by Jeff Lane at
127 [Shockwave Rocketry](http://shockwaverocketry.com), with thermistors embedded.
129 The fins are 3/16 inch birch ply, tapered on the leading and trailing edges,
130 then covered with two layers of 5.7 oz 2x2 twill carbon fiber and a layer of
131 6 oz glass as a sanding veil, all vacuum bagged with West Systems laminating
132 epoxy using a kitchen food saver appliance. The two CF layers are rotated
133 45 degrees from each other.
135 We're moving from the Giant Leap Rocketry 98mm Magnaframe-based Dynawind to
136 G-10 glass tubing this time around. Dynawind is lighter and strong enough,
137 but we want to use glass couplers this time around for more strength, and
138 that leads to fit issues with the Magnaframe-based Dynawind tubing. So even
139 though it's slightly heavier, we're going with an all-glass build this time.
140 We'll lose a little bit of max velocity, but hopefully it'll all hang together!
142 The tailcone is a no-longer-available Giant Leap 98-75mm Slimline tailcone
143 recovered from 2YikStik's wreckage.
145 All rings and bulkheads were cut using a CNC milling machine from 3/8 inch
146 birch plywood. The fin forward and leading edge rings are made from 3/4 inch
147 thick birch plywood, mostly to provide sufficient depth for milled fin slots.
151 I've put all the [build photos](http://gallery.gag.com/rockets/YikStik3/Build/)
152 I took together in one place.
154 Friends who were present for YikStik3's first flight during the
155 [Kloudbusters](http://www.kloudbusters.org/) Airfest 18 launch over Labor Day
156 weekend 2012 took these photos and videos:
158 * [Terry Lee](http://gallery.gag.com/rockets/YikStik3/Airfest18-Terry.Lee/)
159 * [Tom Marble](http://media.info9.net/tag/yikstik3/)
163 The intended first flight of YikStik3 was to be at NCR's Mile High Mayhem 2012
164 on an unreleased [Cesaroni](http://pro38.com) Pro75 6xl Imax
165 reload. Unfortunately, the jet stream was parked over the site yielding
166 strong upper level winds, such that it would not have been possible to keep
167 the airframe inside the waiver cylinder during recovery... so we didn't fly.
169 The motor was certified in early August as the Pro75-6GXL 9977-M2245-IM-P.
171 I was able to fly YikStik3 for the first time at the
172 [Kloudbusters](http://www.kloudbusters.org/)
173 [Airfest 18](http://www.kloudbusters.org/airfest/Default.aspx). They've got
174 a huge waiver cylinder and an awe-inspiring recovery area .. which it turns
175 out we didn't need much of! The airframe achieved approximately Mach 2.2 and
176 21,660 feet above ground. More details will be posted once we have time to
177 analyze the data we collected.
179 This airframe, along with many other things, was lost in the
180 [Black Forest Fire](http://gag.com/blackforestfire.html).