Ekranoplans are a curious class of vehicle; most well known for several Soviet craft designed to operate at sea, flying just above the waves in ground effect. [rctestflight] had accidentally come across the ground effect flight regime himself years ago, and decided it was time to build an ekranoplan of his own.
While ground-effect flight can be quite stable for a heavy, human-scale craft, the smaller RC version suffered more from minor perturbations from the wind and such. Thus, a Pixracer autopilot was installed, and combined with a small LIDAR device to accurately measure altitude above the ground. With some custom tweaks to the Ardupilot firmware, the craft was able to cleanly fly along barely a foot off the ground.
The final effect is almost mesmerizing; it appears as if the craft is hovering via some heretofore unknown technology rather than just flying in the usual sense. It’s still sensitive to breezes and sudden drops in the terrain lead to a temporary escape from the ground effect region, but the effect is nonetheless impressive. It’s a nerve wracking video at times, though, with quite a few near misses with traffic and children. Regardless of the nature of your experimental craft, be cognisant of your surroundings. We’ve seen [rctestflight]’s Ardupilot experiments before, too. Video after the break.
In the 1960s the Soviet Union began experimenting with what they called ekranoplans, ground effect vehicles (GEVs) that were something of a hybrid between a ship and a large airplane. Their stubby wings didn’t provide enough lift for the vehicle to fly in the traditional sense, the craft essentially rode on a cushion of pressurized air produced by the aerodynamic interaction between the wings and the surface of the water. But after decades of testing, the ekranoplan never became much more than a curiosity for American intelligence agencies to ponder over.
Now [Peter Sripol] has built his own version of what the CIA dubbed the “Caspian Sea Monster”, and judging by the video of him “flying” it around a lake, the design seems to tick all the boxes. The advantage of a GEV is that it’s far faster than a ship and more fuel efficient than an aircraft of similar size. They also operate low enough to avoid enemy radar, which made them very appealing for military applications. Not that any of those characteristics apply to an RC vehicle, but at least it looks cool.
Ironically, it took some extra effort for [Peter] to keep his scratch built ekranoplan from getting airborne. Built out of foam covered with aluminum tape, the craft was light enough that even the tiny wings were enough to break it free from the ground effect if it got going fast enough. It didn’t help that the electric ducted fan motors used were probably a bit too powerful as well.
But by carefully adjusting the throttle and control surfaces, [Peter] was able to keep his craft firmly planted in the ground effect most of the time. Seeing the large RC craft floating just a few inches over the water is very impressive, and thanks to the application of some Soviet-style iconography on its burnished aluminum body, it looks like found-footage from a Cold War test program.