拖鞋形飛行器為啥能垂直起落？揭秘最簡易直升機的飛行和控制原理【萌萌戰隊】

Recently a netizen asked This weird aircraft that looks like the bottom of a slipper Why is it driven by an offset propeller Can take off and land vertically like a helicopter and move horizontally This kind of free-flying helicopter was as early as thirty or forty years ago Middle school model airplane teams all over the country will make At that time, the students used the paulownia wood skeleton to add cotton paper and apply oil Make slender wings and stabilizers Mount a stick to the end of the stick 1.5CC engine burning methanol castor oil mixed fuel The center of gravity of the aircraft is at the root of the wing The propeller pushes the rotor to rotate on the bracket and take off At this time, the tilting moment of the rotor lift to the center of gravity It is balanced with the righting moment generated by the centrifugal action of the wing Make the rotor surface keep a certain taper rotation Since the vortex at the blade tip has enough time to sink When the blade turns to the same position again won't get into the wingtip vortex just created Therefore induced drag is lower than with two blade rotors So it's a very efficient helicopter But when the rotor rotates around the center of gravity of the fuselage Its short chords cannot produce Sufficient trim torque to maintain angle of attack So there needs to be a stabilizer behind the rotor The direction of flight is completely determined by the wind on the playground This caused the students below to run along Now it looks like a social death scene So we can cut a piece of foam into a machete Glue it as shown in the picture Coreless motor and 1S small battery can fly in the house but the strange thing is The machete rotor Ability to maintain angle of attack without stabilizers What is the principle of this? So we made a shell according to the shape of the slippers it is divided into two parts The part with the motor mount near the wing tip is the rotor Plano-convex airfoil Next to it is a flat-convex battery compartment with symmetrical cross-section There is a steering gear inside and the steering surface is driven by a pull rod The servo is driven by a special flight controller Its power and remote control commands come from the receiver This receiver gets power from the BEC of the ESC Powered by a lithium battery This helicopter can be thrown out directly when it is released The propeller will push the fuselage to rotate around the center of gravity This causes the axis of the propeller to continuously deflect with the rotor So the paddle disk is like a spinning top whose axis of rotation is disturbed will have a precession effect While the paddle disc is constantly deflecting inward, Also follow the blade rotation 90 degrees upward precession deflection generate head-up moment And the lift acting at about 1/3 of the mean chord length Then push the fuselage to bow around the center of gravity to form a nose-down moment The two balance each other to make the rotor reach the longitudinal moment balance so as to obtain a stable angle of attack Therefore, the machine is precessed by the propeller disk to create trim torque so no need for stabilizers In addition its receiver except the third channel used to control the ESC The signals from the pitch and aileron channels will be sent to the flight controller The flight control contains an IMU inertial measurement unit or an electronic compass chip Set the initial alignment direction or magnetic north pole of the flight controller as a reference direction Once the flight controller receives the forward command from the receiver during flight when the fuselage rotates to the opposite direction to the reference direction send rudder down signal Drive the rudder surface down once Since the rotating fuselage is also a gyroscope This roll disturbance caused by the rudder surface It will follow the 90-degree rotation of the fuselage and precess Changing the rotor cone from horizontal to forward So move to the reference direction back command received The flight controller will turn the fuselage to face the reference direction Let the servo move once And the roll moment produced by the rudder surface this time Still have to precess when the body rotates 90 degrees make the rotor cone backward Fly in the opposite direction to the reference direction In the same way, flying left and right is also controlled in the same way So it still uses the helicopter Principle of cycle variable pitch control Only the flight direction needs to be based on the reference direction Although this is not a serious helicopter at all Maneuvering is like a plastic bag drifting in the wind But it's cheap, it's bomb resistant, it's efficient Of course the most valuable A pair of scrap slippers can be made into 2 sets