## Part Selections ##
-Another intense period of study led to the decision to use
+A period of intense study led to selecting
[DiMarzio](http://dimarzio.com) Area pickups. These are stacked-coil hum
reducing pickups in the standard strat single-coil pickup form factor. The
chosen "standard" set consists of:
|guitarheads.net|||||
|black hard tail bridge||1|16.99|16.99|
+## Body ##
+
+I started out with a 1962 Stratocaster design file created in Alibre by
+user protomachinst6 on CNCzone.
+
+http://www.cnczone.com/forums/musical-instrument-design-and-construction/17659-cnc-32.html
+
+I originally hoped that I would be able to use FreeCAD to modify this design,
+but the STEP import process seemed to lose the ability to keep the various
+sub-assemblies oriented correctly relative to each other. Since Alibre has
+been replaced by Geomagic Design, I pulled down a 15-day trial version of
+that package to one of the Windows machines in the house, and (not
+surprisingly)it was able to read the file just fine.
+
+Another interesting STEP file of the body from a 1962 strat drawn by Marc
+Erasmus is available on [GrabCAD](https://grabcad.com/library/62-strat-asm)
+and it appears at least one person has actually built a guitar using these
+files.
+
+To build the guitar body I want, the existing body design file needs to be
+modified to eliminate the tremolo cut-out and rear cavity, to add screw holes
+for the hard-tail bridge, and to shift the electronics cavity from being
+front-open to being rear-accessible with the front just having 3 holes for
+the volume and tone control shafts and the slot and mounting screw holes
+needed for the pickup selector switch.
+
## Wiring ##
A standard strat has a volume control, 2 tone controls, and a 5-way pickup
--- /dev/null
+# Meh-ga Nuke
+
+## Motivation
+
+Years ago, Bdale flew some [Woot](http://woot.com) screaming flying monkey dolls
+in his [L3 certification airframe](http://gag.com/rockets/airframes/Goblin10/),
+leading to some seriously amusing [videos](https://www.youtube.com/watch?v=q7C-sqdSo8M).
+
+Unfortunately, that airframe was one of many lost in the
+[Black Forest Fire](http://www.gag.com/blackforestfire.html).
+
+At a conference late in 2014, one of the founders of Woot approached Bdale to talk
+about the possibility of another sponsored rocket project for his new venture,
+[A Mediocre Corporation](https://mediocre.com/) and its flagship site
+[meh](http://meh.com).
+
+Bdale had already started thinking about building another "big-ass rocket" ...
+
+After giving it some serious thought, the goal became building something bigger
+than anything Bdale had built and flown before, but that would fit in with the
+"mediocre" theme somehow. Most rocket folks start out flying "three fins and a nose
+cone", so doing a simple rocket of that style seemed like a good starting
+point. The coolest such rocket clan Garbee has ever built was undoubtedly
+[Robert's first high-power airframe](http://gag.com/rockets/airframes/LilNuke/),
+a [LOC Precision](http://shop.locprecision.com/)
+[Lil' Nuke](http://shop.locprecision.com/product.sc?productId=114&categoryId=12)
+kit.
+
+So .. how about a stupidly-large upscale of the LOC Lil' Nuke! A meh-ga nuke!
+
+## Design Details
+
+After a bunch of playing around in [OpenRocket](http://openrocket.sourceforge.net/),
+and considering the limits of the CNC equipment at hand, an airframe diameter of
+approximately 12 inches was chosen. We can fly high on 6-inch research motors
+(first flight planned to be on a James Russell research red-flame "O" motor), and
+fly low and super crowd-pleasing on fast-burning M motors like the
+[CTI Pro98 M3400WT](http://pro38.com/products/pro98/motor.php) in a suitable adapter.
+
+To achieve sufficient stability on an O motor, the nose needs to be pretty
+heavy. Simulation suggests that turning the nose out of solid pine would work
+out just about perfectly.
+
+Because such a heavy nose cone will put significant compression load on the rest
+of the airframe, we'll build internal structure to carry that load rather than
+depending on the airframe material itself. Some quick back of the envelope
+calculations suggest that 3 ribs made of cheap, common 1x2 pine lumber should
+more than suffice.
+
+The fins will be fabricated from nominal 1/2 inch birch plywood, rounded,
+vacuum-bagged with one layer of carbon fiber for stiffness and one layer of
+fiberglass for surface preservation and strength. They will insert into fin
+grooves cut in the forward and aft fin rings and interlocked with two
+intermediate rings. All fin to ring joints will be augmented with chopped
+fiber and/or glass fabric scraps. Once the fin can is fully assembled, an
+extra layer of fin to fin glass across the airframe will be installed to
+help keep the fin can together during landings.
+
+The airframe will be constructed from 12-inch concrete form tubing with the
+inner and outer layers peeled, wrapped with two layers of 6oz fiberglass. A
+section of airframe tubing wrapped with one glass layer will be slit and
+closed down to form a coupler so the main airframe can be built in two pieces
+to ease transportation and flight prep.
+
+Recovery will involve a 3-foot drogue parachute deployed by blowing the nose
+cone off at apogee, and an ARRD will be used to release a 28-foot main chute
+from a deployment bag. For high flights, a reasonable main deploy height for
+traditional "dual deploy" recovery will be chosen. For lower flights, the
+main will be deployed just long enough after apogee to permit the drogue to
+re-orient the airframe, approximating the "main out at apogee" experience.
+
+A side-access electronics bay will be constructed in the valley between two
+fins near the leading edge of the fins. Electronics will consist of one
+each Altus Metrum [TeleMega](http://altusmetrum.org/TeleMega) and
+[TeleMetrum](http://altusmetrum.org/TeleMetrum) boards. The TeleMega is
+overkill, but I'm curious to see what the airframe rotation rates are like
+in flight, and the gyros will capture that. Each will use a single 850mAh
+LiPo battery, and rotary switches mounted in the airframe for on/off. Two
+charge cups will be mounted on the forward ring of the fin can for apogee
+deployment, and an ARRD will be mounted on the other side of the same ring
+for main deployment.
+
+The main airframe tube will contain ribs and additional structure to carry
+the load induced by the nose cone, and to direct apogee deployment gasses
+around the main parachute deployment bag.
+
+Because the kinetic energy at ground impact even under the large main will
+be fairly high, the ring at the aft end of the airframe will be doubled
+to 1.5 inches thick for extra strength.
+
+The airframe will be set up with 1515-sized rail buttons, and use of
+Terry Lee's launch trailer with 20 foot rail is assumed to ensure stability
+for all flights.
+
+## Construction Log
+
+2014.04.16
+Purchased 12 feet of 12 inch concrete casting tube from White Cap, they cut
+it for me into pieces approximately 8.5 and 3.5 feet long.
+
+2014.04.18
+Peeled the tubes inside and out, resulting cardboard measures 12" ID,
+and 12.25" OD. Cut two centering rings from scrap 1/2" OSB to allow use of
+on-hand 3/4" copper water pipe as an axle during glassing operations. I
+ended up cutting the longer piece of airframe tubing to ease the glassing
+process, such that I can "wrap normally".
+
+2014.04.19
+Realized I only have enough glass to do one layer on the coupler. Placed
+order for a full roll of 60" width 6oz E-glass. Used West Systems 105
+resin and 209 extra-slow hardener mixed in 3-pump batches to bond one layer
+of glass and peel-ply to the coupler tube. Took either 15 or 18 pumps total,
+the cardboard tube is much "thirstier" than the PML phenolic tubing I've
+glassed for previous projects. Given how much cheaper the concrete casting
+tube is, this is fine, I'll just need to pay attention to my epoxy stock and
+order more if needed!
+
+2014.04.20
+Peeled the peel-ply on the coupler. Looks adequate for use as a coupler,
+but there are several spots where more epoxy would have made me happier. Will
+compensate when wrapping the airframe tubes. Given how "thirsty" the cardboard
+is, I think the trick will just be to paint the tube with a thick layer of epoxy
+before starting to apply the glass, then be generous when wetting each layer.
projects / web / gag.com / commitdiff