Our Story: Part 2
In our 2016 timeline intro blog, we teased the release of our newest series detailing month by month accounts of the behind the scenes efforts that went into making Vahana a reality. Now it’s time to tackle 2017, a year of accelerated building and development that led to Vahana’s first flight in 2018!
We hope you enjoy part one of the Vahana timeline: January through December 2017.
Global finite element model for structural and modal analysis
- Vahana Alpha One and Alpha Two tail numbers were registered (N301VX and N302VX). The two numbers were selected to reflect Airbus’s heritage of 300 series aircraft numbers coupled with a “V” for Vahana and “X” for experimental.
- The first emergency system unit, which is used in emergencies to disconnect the high voltage system and activate the parachute, was built and tested.
- The first composite parts were completed for the forward wing.
- This month marked the completion of the team’s third subscale vehicle, Omega3 and its first time safely flying with closed-loop controls.
- The full scale “wooden bird” was also delivered to be used for hardware layout, wire routing, and integration risk mitigation.
- A mechanical prototype of the variable-pitch fan was completed by Motivo, along with the tooling for the propeller to be used for motor testing.
- The Vahana team met with the Small Airplane Directorate and discussed the new Part 23 certification guidelines, upcoming electric propulsion certification standards (ASTM F39.05), certification of fly-by-wire systems, and certification of sense-and-avoid.
- The forward wing, the first of the full-scale airframe components, was delivered.
- Vahana’s first structural Test Readiness Review was completed mid-March. The structural validation testing began.
- The remaining fuselage tooling and the first variable-pitch fan hub were completed.
- Data collection used for training the Sense and Avoid system was completed and the Near Earth Autonomy landing zone evaluation sensor package was delivered.
The team with the “wooden bird” (left). Foward wing structural test setup (middle). Variable-pitch fan hub (upper right). Omega3 subscale aircraft in hover (lower right).
- Testing of the forward wing, which included proof loads of +3.8g and -1.5g flight conditions in addition to 4g landing load conditions concluded this month, as did the landing gear preliminary design review.
- The variable-pitch fan assembly was tested up to 500 RPM which is 15% maximum speed.
- The primary battery pack engineering effort was kicked off with Airbus Defence and Space.
- Thanks to a large amount of data annotation, the deep convolutional neural network was sufficiently trained and provided the team with preliminary results, allowing the Component Pre-Flight Review for autonomous hover subscale flight to be conducted.
- The “dry” fitting of the wings onto the fuselage was completed. The full-scale wing was delivered and structurally tested.
- The variable-pitch fan was tested up to 28% speed.
- The detect-and-avoid camera solution was trained to detect multiple objects and can now detect both drones (>550m) and birds (>350m).
- The team demonstrated the wireless activation capability of the Flight Termination System.
- The subscale aircraft completed its first autonomous hover testing (position hold only).
- Aircraft flutter analysis was completed indicating significant margin.
Fuselage assembly (upper left). Finite element modal analysis (lower left). First variable-pitch fan blades delivered (upper middle). Testing the fan (lower middle). Dry fitting of the wings onto the fuselage (right).
- This month the focus of our team was on the final proof testing of major components and integration of those components into the vehicle. Finished components include the battery installation system, mobile command center, and hover-test motors to be used for initial hover flights
- Structural load testing of the fuselage was completed.
- The radar was delivered and the camera vision system was improved to estimate object size.
- The team completed its first FAA certification planning meeting which included participants from A³, Airbus, and APSYS.
- Following the delivery and testing of the second fuselage, several components were installed including the wings, battery retainment system, low-voltage systems, and high-voltage harnessing.
- The team integrated the tilt actuators into the hardware-in-the-loop simulator and tested them under load to verify performance.
- Subscale aircraft testing was expanded to include representative flight test missions and validate flight controls and software readiness. Additionally, system identification tests were completed on the subscale to verify sufficient phase and gain margins.
- The team wrapped up the integration of the first vehicle this month, including final installation of the avionics, testing of the wing-tilt actuators on the vehicle, and installation of the high voltage harnesses.
- The motors, controllers, and fixed-pitch propellers were all balanced and tested. The final motor and controller design was completed by MAGicALL.
- The team obtained a Certificate of Authorization (COA) from the FAA, allowing them to fly the first aircraft at the Pendleton, OR UAS range
The shop at Nest (left). Airframe assembly (middle). Variable-pitch fan testing (right).
- This month the team received and installed the landing gear, vibration tested the motor controllers per the most stringent RTCA DO160 vibration profiles, and the flight test instrumentation was integrated into Vahana Alpha One.
- Additionally, several hours worth of testing was performed on the propulsion unit (motor, controller, propeller) to verify the performance of the end-to-end assembly.
- The team held an Internal Safety Review Board meeting and presented their safety case and flight test plan to the FAA and flight test range.
- Vahana Alpha One was transported and reassembled in Pendleton.
- The avionics, software, controls, and testing teams collaborated to perform simulated flight tests using the hardware-in-the-loop simulator and mobile command center while the aerodynamics team completed hover and low-speed performance analysis including propulsion-unit failure cases.
- Using the subscale aircraft, the vehicle’s resilience to a single motor failure was demonstrated by artificially failing a motor and having the flight software automatically adapt to the failure.
- This month, the team confirmed a date for a safety review with the FAA. Once completed, the vehicle will be awarded a Special Awareness Certificate to enable flight.
- Two major components were delivered including MAGicALL’s high-performance motors with integrated controllers and the battery packs from Airbus Defence and Space.
- The first spinning of the motors marked a major team milestone — the first end-to-end vehicle test. It demonstrated that the overall system was functioning as intended and marked the beginning of the aircraft’s test campaign.
The team with Alpha One shortly before shipping it to Pendleton (left). Loading the batteries (middle). Installing the propulsion system (right). Alpha One in the Pendleton hangar (lower right).
- Zach Lovering