Worlds First Autonomous Ground Effect Vehicle/Ekranoplan? RCTestFlight Collaboration

what you are looking at is an akrana plan or ground effect vehicle autonomously navigating to various preset waypoints on a map using the open source autopilot software known as artypilot this is the story of how this project got here i was watching a video by the youtuber rc test flight about a long-range autonomous boat drone and it struck me as a great idea to do in a chronoplan version everyone in the comments section seemed to be having the same thought rather than run with the idea myself i reached out to rc test flight to see if he wanted to do a joint project it turned out that custom code for arduplane was already being worked on on his end for such a purpose and this collaboration was born i was also curious to see if custom code in arduplane was necessary or if arduplane could be made to work well enough as is so what is ground effect check out these pelicans flying at various heights above the water you will notice the lower pelican which is closer to the water has a smaller flattened out wingtip vortex while the upper pelican which is further from the water has a much larger stronger wingtip vortex the stronger vortex increases drag and thus increases the energy required to fly this is a characteristic of wingspan dominated ground effect the other extreme is cord dominated ground effect where a short stubby wing creates a ram effect and increases the lift more so than decreasing drag notable flights in ground effect include the wright brothers first powered flight and the one and only flight of the spruce goose many concepts are bound to utilize ground effect and these are a few given the many considerations available what went into choosing this is the final configuration while the air fish 8 is probably my favorite wing and ground effect craft those wings are a real challenge to cut using a hot wire cutter which is my primary tool for prototyping i still wanted a cord dominated vehicle though with some wing extensions for roll control and of course we need a massive horizontal stabilizer to help us out as we move in and out of ground effect test vehicle number one was terrible as the v-tail design had no longitudinal stability test vehicle 2 with an additional central rudder was almost as bad test vehicle number three tracked quite well although it would need to be modified with a large elevator to compensate for large center of pressure changes as it moved in and out of ground effect as well as winglets for roll control also when it's out of ground effect the design was working quite well now this will be the first test of the powered winging ground effect uh vehicle um no steering no ailerons no rudder so just a little bit of power and it'll probably just spin in circles but let's give it a shot [Music] for the most part the plane did just go in circles but every now and then you get in a good run usually cut short by the only object in sight i needed to try something else so with the motors in the front it understandably tracks quite a bit better overcomes the resistance that you get on these pontoons here so since i want this to be as autonomous as possible as stable as possible by itself i didn't want to put the motors on the front because of durability they're more protected in the back but probably just gonna have to go with motors in the front so i'll do a run here run or two just to show you um that it tracks a lot better and then probably going to size up after this not a lot left to learn on this guy i don't think now that the basic configuration was selected it was time to get specific in xflr5 after many iterations this was the final design xflr5 is not great for modeling fuselages and other bodies so i left off the pontoons and the fuselage however this allows you to get really really close without all those features xflr5 also has an amazing feature where it allows you to calculate the difference between the aerodynamics in ground effect and out of ground effect so that you don't have any surprises as you move between the two elements which is a big deal on winging ground effect aircraft depending on the design ground-effect vehicles can have dramatic changes in the center of pressure depending on height above the surface they are moving over as you can see here the vehicle essentially becomes instantaneously tail heavy as the nose rises leading to a spectacular backflip the first thing i really needed to figure out before diving into this build was pontoon shape and size using the amazing principles laid out in this book i was able to make some pontoons that got me really close right from the beginning at 10 pounds simulated weight i was quite pleased with how the craft sat in the water i did end up carving a little bit more off the back than the front to get the tail to sit a little bit deeper in the water and increase the angle of attack on the wing but other than that it was good right off the bat so i was on the interwebs learning how to waterproof the electronics for this project and we will be using corrosion xhd on the servos and on the battery and then on the escs and the autopilot i will be using a silicon conformal coating and that is the next step now that i knew what i was building it was time to start building here's a little montage to get you through the next 30 seconds of your life if you are interested in the general construction techniques of this airplane check out this video linked on the upper right after installing the electronics and posing for some glamour shots there was really nothing left to do but fly this thing [Music] [Music] [Music] [Music] [Music] [Music] [Music] [Music] you may remember me saying i would put the motors in the front while clearly they ended up in the back of the craft after much deliberation and taking the airfish 8 and other examples into consideration i decided to take a chance on the rear motors despite my experience with the free flight model thanks to the yaw dampening function in arduplane takeoff is a complete non-event in unstabilized modes the takeoff can sometimes go a little sideways though what followed was a few mornings of testing before the wind would get going i first played around with the center of gravity to find the most reared position i could get away with out of ground effect as this would help the craft be as efficient as possible while in ground effect i also needed to check out the stability modes for general flight characteristics and they were good enough for me without any adjustment in arduplane i found that with careful entry into ground effect and with fine throttle adjustment the akrano plan would maintain its position in ground effect completely hands off next it was time to add an airspeed sensor for throttle control in auto modes while testing one day a kind stranger came out and read off air speeds from telemetry and mission planner as i manually maintained ground effect with throttle when i went back and looked at the log files later indeed he had nailed it thank you kind stranger finally the last test was here after securing a boat and a location for the test the mission was planned on the computer with gentle turns to avoid a wing strike which turned out not to be an issue i found after a few test passes that the air speed needed to be kept higher in autonomous modes than i had needed in stability mode to prevent an unintended landing and then it was time ground effect was entered and i switched into a waypoint mission set for one foot off the water [Music] in my opinion the mission was a total success partially the acronym plan never touched the water and spent about half its time in ground effect it also never rose more than its wingspan of six feet above the water and the big one which was still having an intact craft to hand off to rc test flight to continue the project i cannot wait to see a tighter altitude control implemented among other things to see where this project goes head over to rc test flights channel as i bring the ground effect vehicle and this episode in for a landing please consider subscribing if you think i earned it it really helps also i usually name all my projects but couldn't come up with anything this time drop a suggestion in the comments below if you think of anything clever and let's see if something sticks maybe rc test flight will roll with one of them

Channel: Think Flight

Views: 770,756

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Id: _Cq0ffFiJUY

Length: 13min 33sec (813 seconds)

Published: Fri May 21 2021