Progress continued on the DarkAero 1 prototype in March. Mechanisms and hardware related to the canopy and cockpit were the theme of the month. Projects completed included the installation of the canopy latch mechanism, throttle cable, and instrument panel glare shield. Several remaining tasks were completed on the main landing gear as well.

Canopy Latch Mechanism
In general aviation, a number of accidents have been traced back to the pilot forgetting to latch the canopy. The canopy of the DarkAero 1 was designed to latch automatically once it is closed to reduce the likelihood of this failure mode. The canopy latch mechanism on the DarkAero 1 is built around two rotary latches mounted to the aft face of the seatbelt bulkhead. Each of these latches interfaces with a catch mounted to the canopy frame. This arrangement allows the canopy to latch automatically once it is closed. A simple push button mounted just behind the canopy is used to unlatch the canopy from outside the aircraft. The handle to unlatch the canopy from inside the aircraft will be located in an easily accessible location under the fuselage longerons.

Glare Shield
The addition of the canopy jettison mechanism displaced some of the available area at the center of the instrument panel, thus to compensate, a glare shield with a short vertical face was added to the instrument panel to make up for the lost space. Beyond creating more panel real estate, the glare shield casts a shadow onto the primary flight displays to make them more readable in bright sunlight. It also adds structural support to the top portion of the instrument panel, allowing it to react against the forces applied by the springs in the canopy jettison mechanism. The interior of the glare shield will serve as a location to mount the GPS and XM weather antennas for a short and efficient routing of coaxial cable back to the primary flight display. To avoid interfering with the GPS and XM antennas, the glare shield was made from fiberglass.

One interesting feature of the fiberglass material is its natural ability to scatter light. This allows LEDs to be mounted behind the glare shield to serve as map lights during night flight. The light scattering effect eliminates the need to build and install dedicated light fixtures for the map lights. The glare shield will be painted to protect it from UV light while a few small “windows” of unpainted material will be left on the underside of the glareshield where the LED map lights will be placed.

Throttle Cable
The throttle cable routing had remained an unanswered question for some time. The arrangement of the engine and center tunnel avionics box eliminated the option for a straight cable routing from the engine to the instrument panel. Maintaining cable bend radii within acceptable limits was the main concern with any non-straight routing. A concept cable routing was 3D CAD modeled first to establish bend radii and fastener placement. This arrangement was then replicated on the prototype. The engine was temporarily removed during the cable installation to gain better access to the firewall where fasteners were installed to constrain the cable.

The cable was routed down behind the engine against the firewall, through the nose wheel well, and up to the throttle control handle located just below the instrument panel directly between the pilot and copilot. The throttle handle remains fixed and does not hinge up and down with the instrument panel. A traditional friction lock throttle handle was selected for the pilot interface. The mount to support the throttle handle was built as a folded panel structure that was cut in a flat pattern and then folded and bonded into a three dimensional shape. The structure was then bonded in place in the cockpit.

Brake Lines Routing
The DarkAero 1 uses hydraulic disc brakes made by Beringer that are actuated through PTFE brake lines encased in a braided stainless steel outer sleeve. The brake lines were recently installed on the main landing gear struts. The lines were routed along the back side of the strut and constrained with Click Bond studs and loop clamps.

One challenge with establishing a workable routing involved positioning the segment of brake line at the trailing link with enough slack so that it would not stretch as the trailing link suspension pivots. After a routing path was established and the brake lines were installed, the trailing link was cycled through its full range of suspension motion to confirm that the brake line would not be harmed by the motion.

Pilot Production Shop Update
Construction in the new DarkAero Pilot Production shop is underway! Plumbing was installed for the bathroom and kitchen and the stud walls for the office, classroom, and bathroom were put up. Installation of the internet, electrical wiring, and outlets is in progress. Remaining work includes insulation, drywall and paint, and installation of light fixtures and A/C. Completion of the new shop is targeted for early May, and we are excited to ramp up operations there!

Aerospace Composites Course 
We have continued to run the DarkAero Aerospace Composites Course once a month, as interest remains high. Over the past few months we have improved and added to the curriculum to pack even more valuable information into the two day course. If you are interested in joining the next sessions, register at darkaero.com/courses.

Aerospace Mold Making Course
After hosting the first several sessions of the Aerospace Composites Course, a common interest among students has been to learn more about building molds and tooling. Given the recurring requests, we have decided to create an Aerospace Mold Making Course! The first session of this course, which will be held in June, has already filled up, and additional sessions will be scheduled based on demand. The course will provide instruction on building tooling that ranges from simple, single-use molds all the way up to complex, multi-section, production grade molds. If you are interested in learning more or signing up for a future session, contact us at: courses@darkaero.com 

DarkAero YouTube and YouTube Community 
Our most recent YouTube video showcased several of the mechanisms discussed in this email including the canopy latch, throttle control, and glare shield. You can check it out here: 

A sneak peek of the recent work on the DarkAero Pilot Production shop was shared with Mach 2 YouTube community members. Use the link below to become a member and see the latest on the shop:

Looking Ahead
In April, work will focus on the tasks leading up to the first engine start! This includes installing the remaining segments of fuel and brake lines, fabricating the main gear lock hardware, and tidying up the electrical wiring. Two sessions of the Aerospace Composites Course will be held, which will make for an overall busy month with much to discuss in the next update.