He's a little rough around the edges, we know ... Frank is short for FrankenFLY6, and he's basically a mashup of several FireFLY6 beta prototypes. He's our workhorse and our sentimental favorite, with many a story to tell - like how we played with the idea of a gray paint scheme (see right wing) before going with red. To prove that not all of our birds are as rough as Frank (and maybe, just maybe, to whet the appetites of all of those who have placed a preorder), here's a pic of him hanging out with some of his production siblings amongst the New Hampshire granite:
Frank gets all the tough jobs, the new stuff, the tasks not suited for the faint of heart ... because, well, Frank is expendable, in a good way. He's had a long, successful life and nothing would suit him better than to go out in a blaze of glory proving something important. For the cause.
With that in mind, today we loaded down Frank with double the "normal" battery load (a total of four Thunder Power TP3900-3SPP25 batteries). In addition, he carried a full suite of avionics, including a Naza M V1 for hover control and an APM 2.6 for forward flight control. The APM was decked out with GPS, telemetry, and an airspeed kit (crucial for maximizing flight time). For propulsion, our PowerPACK. Finally, to make it a realistic load out, he was fitted with our GoPro nose cone and equipped with a Hero 3 camera and a wireless video link with dedicated 3S 480mAh battery (for improved video link quality, we like to keep our video power separate from the platform's main power system). In this configuration, Frank weighed in at 3685g (8.1lbs), the heaviest FireFLY6 ever. (Some have asked about why the FireFLY6 weighs as much as it does, and if there are ways to cut down on weight. We've updated our FAQ in response, check it out!)
We arrived at our normal flying field to discover it flooded thanks to the spring thaw. No problem for the FireFLY6.
We did a standard FireFLY6 vertical takeoff, transitioned to forward flight, entered the APM's Auto mode (autonomous waypoint following), monitored and waited. At an average cruise speed of ~32 knots (16.5m/s), and after a vertical landing of course, the result was a total flight time of 32 minutes, 38 seconds.
For those who are looking to use the FireFLY6 in applications where ground range is paramount (mapping, agriculture, search & rescue, and package delivery quickly come to mind), half an hour at such an airspeed results in a total coverage of nearly 30km (~18.5mi). In comparison, viable multicopter solutions generally fly 15-25min at ground speeds of around 5m/s, which would result in a maximum total coverage of about 7.5km (~4.7mi), less than a third of the range that the FireFLY6 demonstrated today. While pure fixed wing platforms can boast higher ground ranges, they come with the weakness of needing large spaces for takeoff and landing, something that is often hard to find in everyday life.
One note ... the PowerPACK was specified to accommodate as many different types of flying as possible, which necessarily means that maximizing flight time wasn't really a goal. Flight times can be extended in multiple ways, and specifying your own propulsion system with maximum endurance as a goal is a good start.
And one caveat ... like Frank, integrating double the battery wasn't exactly pretty. Sometimes a little hack goes a long way, but we'll be on the lookout for supplemental batteries with a form factor that lend themselves to a more elegant integration. Stay tuned.
In the end, the best part is that Frank survives to see another important mission. So we raise our glasses to him, may the legend of FrankenFLY6 live on.