Current engines have fan diameters on the order of 3 m, for example, the General Electric GE90 and the Rolls-Royce Trent. In the case of turboprop engine the use of large diameter propellers made it necessary to employ a gearbox between the output shaft of the gas turbine and the input shaft of the propeller to reduce the rotational speed of the propeller by a factor of at least 10. This dichotomy between requiring high rotational speeds to keep compressor diameters, and therefore frontal area, low and increasing the size of the fan to improve fuel efficiency has been dealt with in the past by reaching a compromise position between the two, thereby making optimization questionable. If the compressor rotational speed is such that at the tip of a representative blade u ~ M, then the relative velocity w at the tip of the fan may be double that, but a speed close to M = 2 is not acceptable from either a performance or noise perspective. Therefore a high value of u is beneficial but the limiting factor in this instance is the growth of compressibility effects because u at the tip of a blade can approach the local sound speed. The study of turbomachinery in Chapter 7 showed that the pressure rise in a compressor rotor depends upon the square of the relative velocity w and Eq. The linear speed of rotation u is proportional to Nr, the product of the rotational speed and the radius at which the speed is to be measured. They begin to face the difficulty that was always apparent in turboprop engines, as discussed in Section 10.9. The turbofan engine has distinct limitations as the bypass ratio increases because of larger diameter fans. Sforza, in Theory of Aerospace Propulsion (Second Edition), 2017 9.2.7 Dual-Shaft High Bypass Geared Turbofan The loudspeaker must be well packed (ideally in the original packaging) so that it is not damaged during transport.Pasquale M. I have to return a loudspeaker because of a technical defect, what do I have to observe? In this case, please contact your retailer or the Monkey Banana team, we will help promptly! If the fault “wanders” with the loudspeaker, it is technically defect. Through this, you can eliminate the possibility of the fault being caused by the signal source or mains socket. Please switch the right and the left loudspeaker, leaving the cables in the original position. One of my loudspeakers is silent, what now? We offer the Monkey Base, which is suitable for our loudspeakers and provides optimal de-coupling. To de-couple from the surface, we recommend the use of a high-quality absorber. The distance for optimal functionality is 20 cm.įurthermore, the room should be optimised acoustically, to eliminate reflections and standing waves. It is also important not to place the loudspeakers too near to the wall, as the bass reflex horn is at the back. The area between the tweeter and the woofer should be at ear height. The ideal distance to your ear is 1.5 m, whereby the loudspeakers should form an equal sided triangle to the monitoring position. What is the ideal set-up for my Monkey Banana loudspeakers? Suitable transformers are available from specialised retailers. If this also doesn’t help, the audio-signal has to be galvanically separated. Unpleasant background noise can be supressed by using high-quality audio-cables. If whistle or hum is audible, please unplug the power supply. Please note: some notebook power supplies cause interference affecting audio-output. It is also possible to operate the loudspeakers over a USB-Interface. In most cases, a high-quality y-cable from 3.5-mm-cinch to 2 x 6.3-mm-cinch is sufficient. I would like to operate my Monkey Banana monitors with a notebook. Please make sure that the switch for selecting the voltage is set correctly! Some models have a switch on the back to switch between 110V/60Hz und 230V/50Hz input voltage. In principal, the loudspeakers can be used in the voltage range specified +/-10 % without any problems. I bought my Monkey Banana Loudspeakers in a country with 230V/50Hz mains power.
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