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I have become very interested in aircraft, and in particular ground effect and VTOL aircraft, since I began working on my previous project (P150). I realised during the P150 project that a supersonic ekranoplan would not really be feasible, not just because of the difficulties in navigating at high speed that close to the ground, but also because ground effect vehicles require long wings, while supersonic vehicles require very short wings.

I then began thinking of new ways to use the ground effect. I had several ideas for light, inexpensive flying boat type craft that could be licensed as boats but would have some of the range and speed of a light aircraft. This could have a commercial application, particularly in parts of the world with a lot of water or flat ground.

I then came up with an idea for a VTOL (Vertical take off and landing) craft. This is not an ekranoplan, but it developed from a sequence of ideas originating from a ground effect vehicle. This craft would have the speed and range of an aircraft, and the hovering abilities of a helicopter. I can see a lot of advantagess to a craft like this in carrying passengers and cargo to remote areas, search and rescue missions, or deploying troops to combat zones.

My aircraft has many things in common with aircraft like the V-22 Osprey. It uses turboprops (turbine driven propellers) instead of jets, and features tilting propellers. It is also a similiarly sized aircraft.

However, my concept would likely have greater redundancy than the V22, since my concept uses four engines, two on each side of the craft, with the centers of thrust quite close together. This means that a failure of one engine or rotor assembly could be compensated for by the other three engines. The V22 has an interconnected drive shaft system whereby one engine can power both props, but a single prop failure or extensive damage to one wing or rotor assembly would be non-recoverable.

The V22, additionally, lacks an ability to autorotate. Autorotation is the ability of a helicopter to produce lift even without engine power. As the aircraft desends, the rotors will turn due to air resistance, and, being airfoil shaped, will produce lift. This lift is normally sufficient to allow the aircraft to make a reasonably controlled, if abrupt, landing. However, the V22’s rotors, being as large and heavy as they are, cannot rotate fast enough without engine power to provide an autorotate capability. My concept, in addition to having four engines instead of two, (thereby making a complete loss of power much less likely) also features smaller and lighter propellers, which may provide an autorotation capability.

I am still performing calculations on this concept, and drawing rough sketches. I have noticed that most of the preliminary mathematics here call for calculation of static thrust. Most of the time dynami thrust is much more useful, since planes are always moving. However, a VTOL craft in VTOL mode is not moving, and so it’s engine must be capable of directly producing enough thrust to lift the vehicle and it’s cargo. Static thrust is, however, difficult to calculate. It is related to the RPM of the engine, the diameter of the props, etc. This is the most important calculation, since it will determine if the craft is at all feasible. It will tell me how fast the props need to rotate, how big they have to be, and how powerful the engines need to be. The V22 uses huge propellers, there is surely a reason why they did not go for smaller ones rotating at higher speeds?