Just what the title states.
Since the Wright brothers, aviation technology for fixed-wing craft has advanced by an order or more. Rotary wing craft on the other hand (I know little about aviation; please correct me!) have advanced significantly by way of lift capacity, and maneuverability. Yet velocity has achieved nothing like the kind of advance seen in case of fixed-wing craft.
Currently there is no rotary wing craft capable of supersonic flight.
Combined with the forward motion through the air, the rotating blades attack the air on one side and retreat backwards on the other. As the aircraft moves faster this poses 2 problems:
There are ideas of new blade actuators that can change the blade for 1) reverse airspeed and 2) supersonic aerodynamics. As you have noticed, nothing has panned out so far...
A rotor on an aircraft/rotorcraft is basically an airfoil section twisted along its length. This twist is also known as the pitch, and in most cases it is variable. On approaching Mach 1 or the speed of sound, shock waves begin to form on an aircraft (eg. on the wings) and there is a sharp rise in drag (known as wave drag). This is due to the fact that at high speeds, the airflow can no longer be treated as incompressible flow. The rotors face the same compressibility effects that an aircraft wing faces near the speed of sound, hence it isn't able to overcome this drag.
Since the question seems about aircraft theory, I'll answer with theory. The short answer is that anything can, and will fly given enough time and effort.
One of the biggest limitations for making a conventional configuration rotary aircraft fly at supersonic speeds is materials. When a rotary blade is inline with the path of travel, it has to withstand significant compression forces along its long axis from the shock. There are three solutions for a conventional configuration - bigger & stronger blade (heavier) new materials, or shorter blades (less lift).
If you don't mind deviating from conventional design, then introducing a shroud around the blades will allow you to remove these forces from consideration by allowing your shroud to absorb the forces of the created shock. You could probably reduce the weight of each individual blade by bracing it against the shroud, (think - beam braced at one end vs both ends) Since the air between a shock wave and expansion waves is sub-sonic. If you're lucky, and physics doesn't hate you, then you may get expansion waves behind the shroud, so your rotor blades will be in a sub-sonic medium. By pumping air from above the shrouded rotor to the underside, you cause lower pressure on top, higher pressure on the bottom, causing a pressure gradient and generating lift.
This is all speculation based on my limited aerodynamics knowledge. In real life physics usually hates you, and you'll get some really messed up expansion waves and shock waves along the inside of the shroud, coupled with some fugly shocks being formed by the rotor blades themselves. Since prototyping has become super expensive, and wind tunnels seem to be a dying race nowadays, this would have to be simulated with CFD, and as far as I know, CFD isn't that fast and accurate yet, which could explain why this hasn't been tried yet.
The Republic XF-84H "Thunderscreech" was a USAF jet fighter modified with a turboshaft engine and a propeller designed to operate at supersonic blade speeds. It first flew in 1955, and the result was a noise that was literally deafening. During ground engine runs, "the prototypes could reportedly be heard 25 miles (40 km) away."
Whereas there may be some advantages of a supersonic propeller, the side effects (the noise) prohibit the use of a supersonic propeller even for military applications, let alone civilian ones.
The question proposes a helicopter with supersonic blades, at least on the blade advancing side of the helicopter. There is no research that I know of that would indicate a supersonic blade on the main rotor of a helicopter will act differently than the supersonic blade on a propeller on an airplane. The assumption is therefore that the blades would experience a very significant increase in drag, and would also produce a very significant amount of noise.
Just what the title states. Since the Wright brothers, aviation technology for fixed-wing craft has advanced by an order or more. Rotary wing craft on the other hand (I know little about aviation; please correct me!) have advanced significantly by way of lift capacity, and maneuverability. Yet velocity has achieved nothing like the kind of advance seen in case of fixed-wing craft. Is a rotary wing craft capable of supersonic flight? How is it limited by contemporary technology?
I'm just wondering because the wing isn't fixed, but they aren't rotary-wings either.
When I took delivery of a new Cessna 182T last year, I did a test flight for certification purposes. During the test flight we had to perform a power off stall but that didn't go as planned... with me who has thousands of hours in a C172 and he had never experienced something like this before. The odd thing is that this only happened during that flight. During later flights this didn't occur... this to happen? (My guess is it is CG related) And most importantly: If I would have continued this "mushing" flight, would it be possible to have entered a flat spin or a simple "drop out of the sky
Generally speaking, What programming language is used in aviation for (ATC Radio, Radar, ILS, Auto-pilot and on-board avionics)? Is there a standard enforced by ICAO? Does every plane manufacturer use the programming language they like as long as it's reliable and it goes through testing? I remember watching a documentary on YouTube last year about aviation and it said something about the EU, after WWII, started making standards for aviation systems inside Europe. I will link the video if I can find it
In a full motion Level C or D simulator like those used by the airlines and for jet type ratings: How should a pilot log the simulator time in their logbook? I.e. Can you log: Total Time Instrument Time Time in Type Cross Country Time Night Time Landings (including night landings) Dual given/received Anything else?
I realise that this question is very broad, but I intend it as an example to illustrate the actual costs incurred by a typical long-haul commercial flight. For this purpose of this question, I would assume the following: A380 or (modern) B747 in typical 3-class configuration Full occupancy 12 hours flight time (or more) Here are the cost position I can think of right now: Fuel Aircraft..., is this cost typically handled as "per flight hour" (as in general aviation), "per flight", or in another way?
Inspired by this question. My knowledge concerning helicopters is quite limited: what is auto-rotation? are there other "rotations" possible? in what do they differ?
There are two main types of supplementary oxygen devices in light aircraft: Cannula: Oxygen mask: What are the major differences between these two devices? Is one more suitable for specific si...
An aviation expert reminded me that a propeller is a wing. While I understand that propellers use similar principles to generate force, it muddied the definition of a rotary wing aircraft vs a fixed wing aircraft. If the propeller of a fixed wing aircraft is considered a wing, what is the distinction between the two? Is it how much surface area each type of wing works on? Is it the direction of force?
Airplanes with propellers were invented a long time ago. After that, jet engines came into existence. My question is: why do we still have propeller engines? The reasons I can think of are: They are cheaper; They cannot achieve very high speed; They are not very noisy (though not always). Besides these, are there any other reasons general aviation airplanes built nowadays don't have jet engines?