Although long or medium endurance and higher altitude cruising unmanned aerial vehicles (UAVs) are not high performance in the sense of an F-22 or SU-30, they are in fact extremely high performance when it comes to maximizing their design’s potential for the unique mission sets they were built to address. Usually this comes in the form of fuel efficiency, altitude, and survivability. With this in mind, the crash of the Global Hawk in the video posted above is incredibly relevant to the RQ-170 story for multiple reasons.
First off, flying at higher altitudes for long periods of time requires an aircraft design that utilizes a high lift yet very efficient wing design. The only problem is that as these aircraft fly higher their speed and maneuvering envelope becomes smaller. As altitude increases even small changes in speed, G force or angle of attack can cause the aircraft to stall and even enter a flat spin. This phenomenon is known in the aviation world as “coffin corner.” So, otherwise small flight control or command anomalies can end up putting the aircraft in a totally unrecoverable state.
So beyond the speculation of advanced Russian jamming equipment and cutting edge cyber attacks, lets look toward a simpler explanation for the drone’s demise in relation to the video posted above. If the RQ-170 Sentinel had a software or communications glitch that caused it to climb when it was already operating towards the top it’s operating ceiling, or to pitch up or roll abruptly, or the engine suddenly quit, the aircraft could have most likely departed controlled flight and return directly to terra firma. No cyber espionage or hidden agendas, just a plain old simple malfunction paired with an unforgiving performance envelope. Could this have been caused by a spoofed enemy command? Who knows, but in this piece lets concentrate on the physics of the situation, not the speculative causality.
Also what this video shows is just how an aircraft such as a RQ-4 or RQ-170, one made of composite materials and designed with a tremendous amount of lift, can literally flutter like a leaf back down to earth once they depart from controlled flight. I have spent some time close up and personal with the Global Hawk series of aircraft and I can tell you they are much, much more fragile in appearance than the stout RQ-170 drone. They are literally made of plastic, their wings flex like a piece of damp pasta and their radomes and components are toy like. Especially the smaller, earlier block version as shown in this clip. As you can see it hits the ground with a thud and surely some of its parts crack or are separated from the airframe, but there is no smoking hole, no massive fireball, no football sized debris field, and almost all of its internal components are surely intact. The RQ-170 put on display in Iran does have significant damage, the leading edge is banged up and punctured, the wings have been harshly split at their natural seams (see previous post for more details on this) and it would seem that the underside of the drone was badly damaged enough that it was not allowed to be shown to the public. Further, the Sentinel in question may have gone down in a slightly different manner than the Global Hawk in this video, where it hit flat but with some forward motion, allowing its wings and underbelly to take the brunt of the hit and then subsequently sliding to a full stop.
I hope this post helps to illuminate just how utterly wrong the quick conclusions that many “military aviation experts” had jumped to after hearing the news that the aircraft was possibly intact. Many could just not believe that there was not a huge debris field, or a smoking hole in the ground after the drone “plummeted from 50,000+ feet.” These are uninformed conclusions and most likely totally misleading under the circumstances. The RQ-170 could have made it back to earth with minimal damage to its upper side, and this video clearly showcases this fact.
A big thanks for a flickr contact of mine sending this over for review!
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