Mar 23 2017

Civvie Production Certified for Flight

The second test flight of the new Civvie design proved to be even more successful than the first. The control cabling issue was indeed resolved without the need for an extensive redesign of the system, much to the relief of everyone involved. Once Captain Jebediah reported that the controls were responding fine when the aircraft was trimmed out in level flight, the controllers back at KSC instructed him to go ahead and continue with the flight plan, which called for flight envelope testing to ensure the Civvie could perform various maneuvers as designed, including stall recovery, steep turns and dive recovery. Once these tests were completed, Jeb returned for a safe landing back on the KSC runway.

Now that the Civvie has been certified for flight, we will begin to schedule missions starting next week that will work through our backlog of observation contracts, which have stacked up in the weeks we’ve been unable to put a plane in the air. In addition to the observation missions, an experimental mission will carry a KerBalloon low-altitude payload under its belly to be dropped over a research site and then inflated.

As these missions are carried out we will continue to monitor and review the performance of the Civvie. Assuming no major design tweaks are needed, we will order more in the near future and C7 will begin large-scale production for the fledgling civil aviation industry.

Flight Data Analysis

The first test was stall performance. When carried out in the Civvie Prototype (see this image) the aircraft would recover slowly, pitching its nose down to pick up speed before being able to climb again briefly until the cycle repeated. The Production model is a much more balanced aircraft, and when the throttle was reduced to idle and the aircraft placed into a stall position and held there, it remained nose up in a “belly flop” position as it slowly descended. The rate at which it fell from 3.5km to 3km never exceeded 20m/s, which is well-within the crash tolerance for all of the landing gear. This means that, if the Civvie were to ever completely lose her engine, she should be able to safely glide down and perform a landing without nosing over and crashing.

The next test for the Civvie was steep turns. This is an area where the wings can stop providing enough lift due to their extreme orientation, which would cause the aircraft to roll over onto its back and nose over into a steep dive that could possibly be unrecoverable. In a series of both left and right turns Jeb first began with a slow 45° bank and then after experiencing no attitude problems followed up with a very steep bank of 70-80° while pulling back on the stick at full throttle to create extra stress, building up to 4Gs of load. As the aircraft is not designed to be aerobatic, rolls were not performed nor was the bank increased to 90° to prevent the aircraft from inadvertently rolling and ending up inverted, which is another flight regime it is not designed for (even though it has been proven it can do a full loop).

With everything going well, Jeb was cleared for the most dangerous test – pulling out of a high-speed dive. After climbing to 4km to give himself enough room, he kept the throttle at full and nosed forwards into a steep dive. He was supposed to pull out at 2km so that any structural damage would give him time to bring the aircraft back under control or bail out. However he was fixated on breaking 200m/s and took the dive down to 1.8km. C7 engineers say they are getting very annoyed with him constantly stretching the flight guidelines, but he insists he would have given up on 200m/s had he gotten closer to 1.5km. Regardless, he was able to recover without the wings or control surfaces of the aircraft ripping off, experiencing a momentary record load of 10.804Gs in the process, during which he admits his vision started to turn rather dark.

Engineers will continue to pull and analyze data after every flight of the Civvie to ensure that it is operating as expected before they can call the design final and begin mass-production for all the eager private pilots waiting to experience fixed-wing flight for themselves.