1/9 DESCRIPTION Title A Supporting System for Pressure Measuring Test of the Entire Aircraft FIELD OF THE INVENTION The present invention generally relates to a supporting system for pressure measuring test of the entire aircraft. BACKGROUND OF THE INVENTION The wind tunnel test is kind of experiments based on the principle of aerodynamics, in which the aircraft model or its components, such as fuselage, wing are fixed in a wind tunnel, by applying artificial airflow stream flow across the aircraft model or its parts to simulate the air a variety of complex flight status and obtain the test data. Wind tunnel is the most basic testing equipment for aerodynamic studies and aircraft development, and every development of a new type of aircraft require a large number of tests in a wind tunnel. The main purpose of the wind tunnel test is to obtain a variation of the aerodynamic parameters of the aircraft model. Evaluation of each aircraft's flight performance, in addition to the elements, such as speed, altitude, aircraft weight and engine thrust, one of the most important criteria is the aerodynamic performance of the aircraft. The entire aircraft pressure measurement test is very important wind tunnel test project in aircraft design, and it is an important source of data for the aerodynamic characteristics and load design. The entire aircraft pressure measurement test will need to support the entire aircraft model in a wind tunnel, pressure testing equipment measuring the various components of the model of the entire aircraft specific flight conditions pressure distribution data, in order to obtain the flow characteristics of the aircraft in artificial airflow environment. The aircraft to be test is inseparable from the wind tunnel model support system of wind tunnel tests; the existing wind tunnel model support system includes rigid support system and tensile wire support systems. When carrying of the entire aircraft pressure measurement test in wind tunnel, usually the entire aircraft model will be secure in the wind tunnel test by supporting structures, which include: tail support, abdominal support, sidewall support, wingtip support, tensile wire support and so on. The support system will interference the flow around the model, the aerodynamic characteristics of the model test results with real aircraft makes the difference; this difference is called the support interference. How to reduce or the correction support interference 2/9 problem is an important content of the test aerodynamics research, it can improve the accuracy of the wind tunnel test data. Therefore, for the support system, in addition to the requirements of small wind tunnel flow field interference and does not affect the model aerodynamic shape, also has a simple structure, small size, good dynamic performance, a wide range of applications and low cost. However, at the same time support system to reduce the aerodynamic interference, aerodynamic forces caused by the vibration of the support system is also difficult to avoid, which makes adding support stiffness and reduce the conflict between the aerodynamic interference of the support system has become more prominent in the hard support system performance is especially obvious. In a prior art called "low-speed wind tunnel large angle of attack tensile wire support system" (YANG ENXIA et al, Applied Science and Technology 28 Volume 1, January 2001), the authors believe that the tensile wire support system can be more good balance increased support stiffness and reduce the conflict between the aerodynamic interference of the support system. However, tensile wire support system has obvious limitations in some models of aircraft pressure test of the entire machine, for example, now a very popular form of flying wing unmanned aerial vehicle small aircraft model organism, tail and wings whole, very thin, when the layout sheets line support system, is often difficult to find the proper intensity set anchor, for example, since the wing edges is very thin, the strength is not high, if set tensile wire support points, it is easily destroyed in the wind tunnel test will wing, and very thin in the wing position is also difficult to set the measuring force days equality bodies. If line support points concentrated in the thick part of the body such as the tensile wire support system will be too concentrated support points exposed the support system stability inherent defects, easily in the wind tunnel tests swing affect test accuracy. Therefore, it is necessary on the basis of the above-mentioned prior art, for a particular form of the aircraft model, for example, the form of the flying wing unmanned aerial vehicle aircraft models, etc., to provide an improved support structure for the aircraft pressure test of the entire aircraft provides a stable support, while both have the advantages of a small tensile wire support system aerodynamic interference. SUMMERY OF THE INVENTION The objects of present invention are to provide a supporting system for pressure measuring test of the entire aircraft to avoid the above problem. In order to solve the above problem, the present invention disclosed a supporting system 3/9 for pressure measuring test of the entire aircraft, to provide support to an aircraft model when it is in the pressure measuring test procedure in a wind tunnel, characterized in that the said supporting system include a rotating disc provided on the lower wall of the said wind tunnel, and two of top tensile wire and lower tensile wire respectively connects the nose of the said aircraft model to the upper wall and the lower wall of the said wind tunnel, two supporting bar are fixed welding to the said rotating disc, the top of the said two supporting bar are respectively rotating connects with the left and right wing tip of the said aircraft model by ball bearings. Preferably, the said two supporting bars are retracted extending from the left and right wingtip of the aircraft model to the said rotating disc. Preferably, the said supporting bars include a first arm, a second arm and a bracing arm, the lower of the said first arm connects the said rotating disc, the top of the said first arm rotating connects the lower of the said second arm by ball bearings, the top of the said second arm rotating connects the wing tip of the said aircraft model, the said bracing arm respectively rotating hinges to the middle of the said first arm and second arm. Preferably, the said bracing arm is a retractable sleeve structure. Preferably, the said first arm is a retractable sleeve structure. The supporting system for pressure measuring test of the entire aircraft of the present invention has mixed characteristics of tensile wire supporting system and the rigid supporting system, at which the tensile wire difficult connect to the wing tip of the aircraft used rigid supporting structure, and at the nose of the aircraft keeps the tensile wire support. So, the present invention both have the advantage of the tensile wire supporting system with small aerodynamic interference and rigid supporting system with good stability and maturity technology. DESCRIPTION OF THE DRAWING The following drawing is only for the purpose of description and explanation but not for limitation, wherein: Figure 1 shows the top view of a typical unmanned aircraft model; Figure 2 shows the side view of nose of the aircraft model in Figure 1; Figure 3 shows the perspective view of the aircraft model in Figure 1; Figure 4 shows the schematic structural view of the supporting system for pressure measuring test of the entire aircraft according to an embodiment of the present invention; Figure 5 shows the schematic structural view of the supporting system for pressure 4/9 measuring test of the entire aircraft according to another embodiment of the present invention. DESCRIPTION OF PREFERRED EMBODIMENT In order that the present invention can be more readily understood, reference will now be made to the accompanying drawing to illustrate the embodiments of the present invention. Figure 1-3 shows a typical form of flying wing unmanned aircraft model 100, in which Figure 1 shows the top view of a typical unmanned aircraft model; Figure 2 shows the side view of nose of the aircraft model in Figure 1; Figure 3 shows the perspective view of the aircraft model in Figure 1. Seen in Figure 1-3, for this form of flying wing unmanned aircraft model, because the aircraft models 100 has a small body, the tail and wing as a whole are very thin (seen almost no visible tail or that the tail section is quite weak), when layout the tensile wire support system, it is often difficult to find the proper intensity location settings support points, for example, since the wing edge is very thin, the strength is not high, if set tensile wire support points, it is easily destroyed the wing in the wind tunnel test , and it is also difficult to set the position of the measuring force balance mechanism in the thin area of the wing. If line support points concentrated in the thick part of the body such as the tensile wire support system will be too concentrated support points exposed the support system stability inherent defects, easily in the wind tunnel tests swing affect test accuracy. According to the above problems, the present invention provides a supporting system for pressure measuring test of the entire aircraft, Shown in Figure 4, which shows the schematic structural view of the supporting system 1 for pressure measuring test of the entire aircraft according to an embodiment of the present invention, the support system is used in the entire aircraft pressure test of the entire aircraft to provide support to aircraft model 100 in the wind tunnel (not shown), in the environment of the artificial airflow measuring, the pressure test equipment will obtain the pressure distribution data of various components of the entire aircraft model 100 , in order to obtain the flow characteristics of the aircraft flight conditions. Referring to Figure 4, the supporting system 1 for pressure measuring test of the entire aircraft in the present embodiment comprises rotating disc 11 disposed on the lower wall in a wind tunnel, and two of top tensile wire 12 and lower tensile wire 13 respectively connects the nose of the aircraft model 100 to the upper wall and the lower wall of the wind tunnel, two supporting bar 14, 15 are fixed welding to the rotating disc 11, the top of the two supporting bar 14, 15 are respectively rotating connects with the left and right wing tip of the said aircraft model 100 by ball bearings 16, 16'. Wherein, the pitch angle of the aircraft model 100 is controlled by the top tensile wire 12 5/9 and lower tensile wire 13 through the top wire wheel 17 and lower wire wheel 18 respectively fixed to the upper wall and lower wall of the wind tunnel. Seen from the drawing, the supporting system 1 for pressure measuring test of the entire aircraft has mixed characteristics of tensile wire supporting system and the rigid supporting system, at which the tensile wire difficult connect to the wing tip of the aircraft used rigid supporting structure, and at the nose of the aircraft keeps the tensile wire support. So, the present invention both have the advantage of the tensile wire supporting system with small aerodynamic interference and rigid supporting system with good stability and maturity technology. In the actual pressure test for the entire aircraft, the length of the tensile wire 12, 13 can be adjusted with the action of the wire wheel 17, 18, so that the nose can be rotated about the ball bearings16, 16' connected to the wingtip of the aircraft model 100 to tilt up and down action, in order to measure the aerodynamic characteristics of the aircraft model 100 for different pitch angle. When we need to measure the aerodynamic characteristics of the aircraft model 100 in different yaw angles, we can rotate disk 11, and therefore driven the two supporting bars 14 and 15 to make the airplane model 100 rotate. Obviously, between the supporting bars 14 and 15 and the aircraft model 100 is a rigid support, therefore, during the rotation of the rotating disk 11, the aircraft model 100 can be very convenient to drive, and the stability of support and rotation to be significantly better than tensile wire support. Further, when the rotating disk 11 is rotated, it is possible to relax the density of the wire wheel 17, 18 to adjust the length of the tensile wire 12, 13 to deflect the direction of the nose. To this point, it is particularly different from the existing tensile wire support system, which in order to adjust the deflection angle of the aircraft model, two rotating discs connected with tensile wires must be provided to the upper wall and the lower wall of the wind tunnel, the aircraft model must be rotated with the combination rotation of the two discs, and also, we need to re-adjust the length of each wire , to ensure that the status of the aircraft model to meet the test requirements, which result in a very large amount of labor, adjusting work complicated, multi-parameter, easy mistakes resulting in rework. For the supporting system 1 for pressure measuring test of the entire aircraft, we only need to set up a rotating disc 11 on the lower wall of the wind tunnel, for supporting two supporting bars 14, 15 can be a structure for a more big simplification, do not need to like the existing tensile wire support system as provided two rotating disk and the head parts of the line with the wind tunnel of the fixed point (wire wheel position) with the aircraft does not need the model a deflection and movement. That is, in the supporting system 1 for pressure 6/9 measuring test of the entire aircraft, the top tensile wire 12 and lower tensile wire 13 are respectively connected to the fixed to the wind tunnel upper wall and lower wall of the tensile wire wheel 17,18, the position of the wire wheel 17,18 relative wind tunnel and fixed, it does not need to be fixed on the rotating mechanism with the deflection of the aircraft model is rotated, accordingly, the present invention line 12, 13 and control system connected thereto, such as the tensile wire wheel 17, 18, etc. can be without considering weight, maneuverability, and other parameters, but due to the fixed properties of the connection, may be provided thereon with a variety of complex joint measuring device. Furthermore, because the tensile wires 12, 13 and the connected operating system, such as wire wheel 17, 18 are non-mobile structures, the adjusting tensile wire length of 12 and 13 will become very convenient when the aircraft model needs to adjust deflection, we only needs to adjust the length of 12 and 13 to determine the state of the aircraft model, which greatly reducing the workload, to some extent, saving manpower, improve efficiency, and to avoid the complicated adjustment procedure repeated rework, measurement, calculation and other issues. In addition, compared to the existing tensile wire support system, in present invention, the pressure test support system 1 also has an obvious advantage, that is, since in the present invention, wire 12, 13 do not need connected with the rotating disc 11, the wire wheel 17, 18 do not fixed connected to the rotating disc 11, therefore, the size of the rotating disk 11 does not need to consider the mounting position of the wires 12, 13, in the actual work this is also very important, because the size of the wind tunnel is limited, and if we can minimize the size of the support structure fixed in the wind tunnel, we can also minimize the interference of the air flow. In the present invention, due to the size of the rotary disk 11 has no relation with the mounting position of the tensile wire 12, 13, that is, without considering the wire wheel 17,18 fixed problems, therefore, the rotating disk 11 can be sufficient in intensity as much as possible to reduce its area. Be seen from Figure 4, the area of the rotary disc 11 is significantly less than the projected area of the aircraft model 100, its diameter is significantly less than the distance between the two wingtip, therefore, in one particular embodiment, two supporting bars 14, 15 are retracted extending from the left and right wingtip of the aircraft model to the rotating disc in order to reduced area of the rotary disc 11. Figure 5 shows an improved supporting system for pressure measuring test of the entire aircraft base on the embodiment of Figure 4. As shown in Figure 5, the supporting system 1' for pressure measuring test of the entire aircraft of the present embodiment also comprises rotating disc 11 disposed on the lower wall in a wind tunnel, and two of top tensile wire 12 7/9 and lower tensile wire 13 respectively connects the nose of the aircraft model 100 to the upper wall and the lower wall of the wind tunnel, two supporting bar 14, 15 are fixed welding to the rotating disc 11, the top of the two supporting bar 14, 15 are respectively rotating connects with the left and right wing tip of the said aircraft model 100 by ball bearings 16, 16'. Wherein, the pitch angle of the aircraft model 100 is controlled by the top tensile wire 12 and lower tensile wire 13 through the top wire wheel 17 and lower wire wheel 18 respectively fixed to the upper wall and lower wall of the wind tunnel. Different from the embodiment shown in Figure 4, in the present embodiment, the supporting bars 14, 15 are respectively include a first arms 141, 151, a second arms 142, 152 and a bracing arm 143, 153; the lower of the first arms 141, 151 connects the rotating disc 11, the top of the first arm 141, 151 rotating connects the lower of the second arm 142, 152 by ball bearings 16, 16', the top of the second arm 142, 152 rotating connects the wing tip of the aircraft model, the bracing arm 143, 153 respectively rotating hinges to the middle of the first arm 141, 151 and second arm 142, 152, as shown in Figure 5. And, the bracing arm 143, 153 is a retractable sleeve structure. In the embodiment shown in Figure 5, the supporting bars 14, 15 are split into two parts, the sides lip angle of the aircraft model 100 can be adjusted by adjusting the bracing arm 143, 153 and the second arms 142, 152, so as to measuring aircraft model 100 aerodynamic characteristics in different sideslip angles. In order to further increase the range of adaptation of the supporting system 1' for pressure measuring test of the entire aircraft of the present invention, the first arm 141, 151 is a retractable sleeve structure, which can be applied to various size airplane model, shown in Figure 5. That is to say, if in the case of that only the bracing arm 143, 153 is a retractable sleeve structure, it is may be partially adapt to a smaller or larger size of the measurement test of the aircraft model, but the sides slip angle ranges of the aircraft model 100 can be adjusted will be greatly hampered, but in present embodiment, the first arm 141, 151 can be also in the form of retractable sleeve structure, the spacing of support bars 14, 15 can be expanded with the first arm 141, 151, so that it can be adapted to different sizes of the wingspan of the aircraft model to eliminate this restriction. In summary, in the present embodiment, it should be noted that setting bracing arm 143, 153 a retractable sleeve structure, its purpose is to adjust the sideslip angle of the aircraft model 100, while setting the first arm 141, 151 the sleeve structure, its purpose is to adapt to the different sizes wingspan of the aircraft model, so that their role and function is completely 8/9 different, the skilled in the art can not obtain its structure by mutual association imagination and its innovative is obvious. Whilst the above has been given by way of illustrative examples of the present invention, many variations and modifications thereto will be apparent to those skilled in the art without departing from the broad ambit and scope of the invention as herein set forth in the following claims.