Jumper X73S, the test

This is probably one of the smallest multirotors with brushless motors. It measures only 7.3 cm diagonally from motor to motor. It's less than a Tiny Whoop! This device is a miniature jewel. But what is it really worth?

Tour of the owner

The structure of the X73S is reduced to its strict minimum: no carbon arms, the device is made of a single electronic plate including the flight controller and the ESC. A spartan architecture, reminiscent of what is found inside nano multirotor type Cheerson CX-10. The engines are models 1103 to 10000KV a bit special. They are placed upside down, base screwed up ... yet the propellers are positioned on the top. In fact, the motor shaft does not come out from the usual side, but from the side of the base! The propellers are transparent quadripales 4.6 cm in diameter, so 1.8 inches that sink on the shaft without screws. A support for the camera and the battery, in two parts, takes the main plate in sandwich. Below, the battery holder (not supplied) is a nacelle. It allows to slide batteries of 2.4 cm in width and 0.8 cm in thickness, with a plug of type Molex 2.0. Under the nacelle, it is a kind of foot, or base, which is used to lay the X73S on the ground. An important element, as we will see!

Continuation of tour

Above the plate is the camera combo - video transmitter, the micro receiver radio - a FrSky version on the device I bought. The FPV combo is a model close to the CM25 AIO, based on a 600TVL camera associated with a 5.8 GHz transmitter of 25 mW and 32 channels. It is protected by a plastic case and presented vertically compared to competing models. But the image is in the right direction. The antenna is of the dipole type fixed with a pigtail connector. Interesting, as it can act as a fuse in case of crash, and facilitate the change of antenna if necessary. To choose the transmission frequency, there is a dips box on the back of the combo. The whole weighs, with the propellers but without the battery, 31.21 grams. Not bad ! What battery is needed? The technical data sheet indicates that the recommended model is a Lipo 1S 600 mAh. Be careful, many batteries with these characteristics exceed the size of the nacelle!

Before taking off

The flight controller of the version I chose is a Naze32 flashed with Betaflight. No USB port on the plate, but a small connector. The manufacturer provides a cable to connect this connector to a USB port. The settings of Betaflght (version 3.0.1) are factory-made, including PID. All that remains is to pair the radio receiver with the radio control. On the FrSky version that I have, you need a radio compatible with D8 mode. A button on the receiver, easy to access, allows to start the pairing procedure. At first, do not try to modify the settings, rates and PID, they are very well chosen. On the other hand, it is essential to ensure that all the channels of the radio are correctly associated, that the arming is configured, as well as the flight modes (Horizon, Angle, Acro, Airmode). Do not forget to configure the Failsafe. In case of loss of radio link without automatic shutdown of the engines, outside, you will never find your machine!

First take-off

As usual, our first flight is made in direct view, as a precaution. And it was better! Once the engines are armed and the gases are pushed, one of the propellers will not rotate. The reason ? It is too pushed on its shaft and touches the components of the engine arm! It must be removed and reinserted less deeply. Second attempt ... and new failure. This time, it is the radio antenna that blocks a rear propeller. Third attempt: the X73S turns immediately. The faulty is the power cable that blocked an engine. Fourth attempt, the engines start and the X73S lies down on the side. The reason ? He lost to takeoff, two engines hit the ground. As the motors are reversed, the rotating part is down. It is therefore important to ensure that the X73S is placed on a perfectly flat surface and does not take a tilt at take-off. The solution is to put it on a flat support and to push the gases frankly. The device is very reactive, quite nervous: it must be contained so that it does not leave too fast. Note that diodes are placed just after the ESCs on the motor arms, just below the propellers. The transparency of the propellers does the rest: they are illuminated in flight. Great!

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Eachine Racer 180, the test

This is a device that stands out from the competition. Its principle, reciprocating engines, is not new, but it is very rarely encountered. Eachine wanted to give it a look "flying car", for a rather approximate result. Note that the device was given to us by the Banggood shop. As usual, tell us if you think the practice has influenced our judgment.

Tour of the owner

The Racer 180 holds more than one tank of assault than a car ... Its frame is imposing, with large plates of carbon horizontal and vertical. On the balance, it is displayed at 444.9 grams (without its battery). Here is a heavyweight ... yet equipped with small 4-inch triple helices, and without possibility of installing larger ones. No indication on engines, but these are, according to the data sheet, 2205 to 2350KV. Rather sturdy, therefore, and animated by 20A ESCs well hidden inside the frame. A little too well hidden, moreover, since they are not directly accessible. These are 4-in-1 models. The arms of the engines are of the tubular type, made of carbon. They are mounted in such a way that they turn on their axis, driving the motors in a forward or backward inclination. This inclination is controlled by two threaded rods connected to a single servo. It is oddly placed, too big to be fully housed inside the frame, yet voluminous ... and rather empty. It therefore passes over to the side.

Continuation of tour

The Flight Controller is a SP Racing F3 under Cleanflight 1.13. The microUSB connector is easily accessible by an open notch in the left side of the device. This flight controller is connected to a 2.4 GHz Eachine IA6 radio transmitter, compatible with the AFHDS 2A format. The connection is not in PPM, so there are wires for each motor. To this is added a connector for the servo, placed on the pins 2 of the receiver. The camera at the front is a 1000TVL mounted on a hinge. It is possible to change the inclination by using two screws, but they are not easy to access. This said, we'll see, tipping the camera is useless! It is connected to a 5.8 GHz video transmitter glued under the top plate. It is advertised at 350 mW and 40 channels including the ImmersionRC Raceband. In fact, it is a Skyzone TS5823S that offers well the 40 channels and the Raceband, but with a power of 200 mW "only". That said, the maximum power allowed in Europe is 25 mW, so it is too much to be in order. The settings go through a series of Dips that are accessible at the back of the machine, via a notch in the top plate. A polarized mushroom antenna is provided in the box.

End of tour

Almost all of the upper plate and the two side plates form a nacelle for receiving the battery. The model delivered is a Lipo 4S 14,8V of 1100 mAh and 30C. Very small, since it measures no more than 8 cm in length while the nacelle is designed for a battery that can reach 11 cm in length (and 3.5 cm in width). With this battery, the weight of the Racer 180 passes, in order of flight, to 656.7 grams. A row of LEDs is located on the top of each side of the frame, insulated from the carbon with a plastic strip, fed by cables welded to the outside. The nacelle for the battery is covered by the plastic fairing, held by 4 pins. Two copies are delivered in the box, one sky blue and one white. A buzzer completes the endowment of the Racer 180. The device is an RTF model, so it comes with a Eachine i6 radio control, equivalent to a Flysky i6. Everything is already preset. Convenient !

Before taking off

Small passage in Cleanflight Configurator to check these settings, arming method, failsafe, rates, etc. By removing the propellers, the necessary precaution when accessing the flight controller with the battery connected, it is realized that the nuts are difficult to unscrew even with the small key provided in the box. To screw them back is, one would expect, just as painful. Cleanflight indicates several important information. The arming of the motors is not specified, so it is the usual method, with the left joystick, which is activated. The SWB controls Angle mode and Acro mode. Nothing is indicated for the SWC switch ... yet activating it produces a beep. The reason is that it is directly related to the servo that controls the inclination of the motors. Arm with all the switches up ... gives nothing. In fact, it is necessary to switch the SWC switch to the middle position for the arming to be operational. Note in passing that the diodes on the side are very powerful, but that they are seen virtually no longer when the fairing is in place. For the record, the settings of the remote control are inoperative.

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Lyre: musical instrument

Lyre - a stringed musical instrument that looks like a case of the violin. This tool is also known as organistrum or hurdy-gurdy. When playing the lyre to keep on your lap, and while the game is played at the same time most of the strings. Popular since the X century musical instrument is now used less frequently. But thanks to the amazing sound, the original design of the lyre still remembered. 

sound Features 

The sound of the lyre wheel is provided by the operation of most of the strings, as a result of their friction on the wheel vibration occurs. It is noteworthy that most of the strings are only responsible for the monotonous buzz, and song playback is provided by a game or two. Lyre sounds powerful, sad, monotonous, somewhat nasally. And to soften the sound of the string has long been wrapped with linen or wool fibers. An important role is played by the exact alignment of the wheel - it should be smooth and nakanifolennym.

Device 

Three-stringed lyre has a deep wooden cabinet in the form of eight, two flat decks, which are bent shell. The upper part of the tool head is complemented with wooden pegs, which allows you to adjust the strings. Lyre has a short Kolkova box, which often ends in a curl. Since the rim protrudes outward, hiding it under a special bast fused in an arc shape. 

The upper deck has a hole in it is the same keyboard-porozhkovy mechanism with the keys. They, in turn, are simple protrusions with wooden slats. When the musician presses the keys, just projections contact with the strings, uttering sounds. The projections are mounted so that they can be displaced in different directions, thereby aligning the audio range. tool body laid out in such a way that the amplified sound of a string. Sound Amplification occurs due to vibration of strings, which are caused by wheel traffic. 

Features strings 

Hurdy-gurdy - instrument with three strings vein: melodic called spivanitsa, or melody; two Bourdon called bass and pidbasok. If melodic string in design passes through the inside of the box, then the drone - on top of it. All strings are arranged so that they come into contact with the wheel rim. It is before work is rubbed with resin, allowing the strings sound smoothly audible. Flatness of sound obyuespechivaetsya smooth surface and precise wheel alignment. The melody is created or performed by pressing the keys at the side of the box cut-outs. 

Historically, strings were created on the basis of living, although today more and more popular strings of metal or nylon. To get the desired tone and quality of sound, the band wrapped strings of cotton or other fibers, and should have been more coverage on Bourdon. If wool is not enough, the sound is either too dull or too harsh, especially in the upper range. 

What today? 

In Russia today, infrequently used lyre. Musical instrument (the photo shows all its colorfulness) remained in the orchestra of the State and the People's Choir of Belarus. It is noteworthy that the hurdy-gurdy is used in medium rockers: group Led Zeppelin, In Extremo selected tool because of its unusual sound. Today, an instrument almost forgotten, but some bands sound unusual for hurdy-gurdy is left as the highlight of his work. 

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