Abstract

The propulsion force will decrease as 40kN and 18kN as rotation speed increases from 50r/m to 100r/m respectively at R=7.7m and P=2,566kW in one blade of helicopter. As the rotation increases from 50r/m, 100r/m, 200r/m to 500r/m the propulsion has become decrease from 11kN, 4.5kN, 5.5kN to 0 respectively at angle f= 24º, R=9.7m & P=1,566kW in one blade of helicopter. The relationship between propulsion force and time with changing inclination under various R, mass and rotation in a blade of helicopter. The propulsion may increase when time increases from 0~2s. Meantime with increasing inclination to 13º it may increase to 400kN. The propulsion force may increase as the angle f increases in proportion. The high rotation firstly and then heavy blade mass and radius has been turned and arrived in.

Keywords: Propulsion modelling; One blade; propulsion force; rotation; time; helicopter; inclination q; angle f; radius R;

 

Introduction

The helicopter is prevail in modern society because it has rapid flight than other usual vehicle. It accommodates more people to proceed transportation task in large helicopter. For example the injured one and substantial is needed rapidly arrangement. It can wield its effect in modern war due to its swiftness and mobile. It has attacking capacity in large scope. So it is investigated for the purpose of this utility. The propulsion of helicopter is studied to search its effect on speed which is important simulation. It is known that the speed will decline the propulsion. So the high rotation will be searched further because of its result of high speed. The propulsion determines the speed directly. For the sake of the helicopter security the loaded blades force has been researched widely in papers on current. In this paper the propulsion force has been investigated with rotation speed and time and discussed in details. Meanwhile, because of the function of heavy load in it the attack ability with many missiles weapon may be possible in war. On the other hand it will be affected by load so it is determined by a certain load. To promote the load it will be designed big for example the blade radius length and quantities and other like angle f and rotation speed & inclination. So as to incline the load and speed it is investigated three directions in this paper i.e. rotation, angle f and radius. Through comparing with each other the advantage is searched in this study to further investigation later. On the other side, the speed of helicopter is also important one for us to search further in this paper because it is significant property to evaluate its function. Speed is a key factor to complete its task rapidly so here the detail situation is discussion to model its function. Overall, the propulsion and speed of helicopter is important factor so its effect is needed to search in detail. The turn is concluded in total according to this model. In this paper the acceleration is computed in terms of theory dynamics to use this research. It is supposed that five blades exist in. The lift force is second factor to consider because of its neglect role. The speed is a factor to model for finding the relation of them. It is to promote the property of helicopter through modelling is our destination finally [1-28].

Modelling and Equation

In the schematic graph as Figure (a &b) 1 O is blade centre; q is inclination, º; FL is lift force, N; Fn is normal force, N; Ft is rotational force, N; Fp is propulsion force, N; Mc is the mass center, kg. The model equation has been deduced as below. It is known that the plane is vertical to the Figure 1(b) plane. Figure 2 shows the relationship between the propulsion force and rotational one in rotational plane of blades.

  • Propulsion and Lift force
  • Force in rotational plane

Figure 1: The schematic of propulsion force in a blade of helicopter.

Figure 2: The schematic of force and speed blade of helicopter.

Mass center Mc’s orbit equation is

(1)

Here it has

(2)

It has been derived, it is

(3)

It has been secondly derived, it has

(3)

Since

(4)

It has

(5)

Here  (6) and  (7)

(8)

(9)

(10)

So it has

(11)

Here r is the radius of blade, m; n is the rotation, r/m; am is center of mass in blade, m/s2; q is inclination, º; f  is angle a+b, º; vp is the speed of helicopter，m/s2; t is the time, s; m is the mass, Kg.

Discussions

The relationship between propulsion and time is investigated as below with different parameters. Three conditions of pitch angleb, angle f and blade radius R as correspond parameters to compute for helicopter’s blade. It gains three groups of value to estimate theses. In this paper all the relational parameters have been calculated on the helicopter and its blades. It is tried out that finding intrinsic relationships happens in helicopter flight in order to simulate the data changing conditions. The propulsion force and time is searched here according to different pitch angle, angle f & blade radius in helicopter while the speed and time is in research of the rotation of blade and mass of helicopter with different inclinations. The main task has grasped the force and propulsion speed with the time. The other parameters like blade pitch angleb, anglef, and blade radius r & inclination q are used to proceed as well. The detail discussions are shown as below.

  • R=7.7m; P=2,566KW
  1. b) R=8.7m; P=3,566kW
  2. c) R=9.7m; P=2,566kW
  3. d) R=9.7m; P=3,566kW

(e)          R=9.7m; P=1,566kW

Figure 3: The relationship of propulsion and rotation with various angle f= 5º, 20º, 30º &47º with different power 1,566kW, 2566kW & 3,566kW and radius R=7.7mˎ 8.7m &9.7m in one blade of helicopter.

In Figure 3(a~e) the propulsion force will decrease as 40kN and 18kN as rotation speed increases from 50r/m to 100r/m respectively at R=7.7m and P=2,566kW in one blade of helicopter. With increasing the power as 1,566kW and 2,566kW it will increase as 8kN and 12kN at the R=9.7m and rotation 100r/m in one blade in this figure. As the angle f increases it can increase as well.  The former changes as f= 5º, 20º, 30º &47º the later can increase as 10kNˎ 8kNˎ 6kN & 2kN respectively at the rotation of 100r/m as seen in Figure 3(e). The former has been in proportion to the later. It is conceded with the logic well. With increasing the radius from 7.7m to 9.7m it decreases from 18kN to 16kN reversely. It expresses that under a certain power the force can decrease with the radius increasing. As seen in Figure 3(d) the propulsion attains 3kN at the f= 47º in one blade of helicopter. That is the highest one with R=9.7m and P=3,566kW, totally the propulsion force attains 20kN i.e. 2tons loaded here with five blades in one helicopter with the rotation 400r/m. As seen in Figure 3(a) the propulsion has become 12kNˎ 10kNˎ 8kN & 4kN with angle decreases to 47º, 30º, 20º &5º and 7.7m &2,566kW at the rotation 200r/m. Thereby the parameters as radius 7.7m and power 2,566kW is enough to design helicopter blades due to the enough propulsion force like 2tons in this least condition of 5º. as the parameters change to 8.7m and 3,566kW the conditions are the same so we speculate that radius less than 7.7m with power less than 2,566kW is feasible too from cost respects. If the propulsion force and radius draw has been out the rational scope may be exhibited.

(a)          R=9.7m; P=3,566kW

 

  1. b) R=9.7m; P=1,566kW
  2. c) R=10.7m; P=1,566kW

Figure 4: The relationship of propulsion and rotation with various angle f= 5º, 15º, 20º &23º with different power 1,566kW & 3,566kW and radius R=9.7m~10.7m in one blade of helicopter.

In Figure 4(a~c) it is found that as the rotation increases from 50r/mˎ 100r/mˎ 200r/m to 500r/m the propulsion has become decrease from 11kNˎ4.5kNˎ 5.5kN to 0 respectively at angle f= 24ºˎ R=9.7m & P=1,566kW in one blade of helicopter. Meantime, the propulsion will become as 4.5kNˎ4kNˎ3kN &1.3kN at when the angle changes as f= 24ºˎ20ºˎ 15º &5º and the rotation n=100r/m. It means that with decreasing the angle the propulsion will decrease as well. On the other side, the propulsion has been 2.3 times of the adjacent angle i.e. 24kN &10kN and 10kN &4kN at the 50r/m and 100r/m from here respectively. When the rotation reaches the 500r/m the propulsion will attain 0, which means that the least force will be formed here. So the rotation accesses beyond this one the neglecters force has been produced. This benefits from the fact for us to use low rotation speed in order to promote its propulsion force. Figure 4(c) shows that the higher radius 10.7m may cause the lower one with maximum 9kN at power 1,566kW.

  • R=8.0m; M=220kG; n=600r/m
  1. b) R=8.7m; M=380kG; n=500r/m
  2. R=8.7m; M=380kG; n=400r/m

(d)          R=9.7m; M=380kG; n=450r/m

 

  1. R=8.7m; M=380kG; n=300r/m
  2. F) R=7.7m; M=380kG; n=300r/m.

Figure 5: The relationship of various propulsion and time with various rotation speed n=300r/m, 400r/m, 450r/m, 500r/m & 600r/m and R=7.7m, 8.7m &9.7m, a blade mass M=220kG &380kG in helicopter.

Figure 5(a~f) shows that the relationship between propulsion force and time with changing inclination under various R, mass and rotation in a blade of helicopter. The propulsion may increase when time increases from 0~2s. Meantime with increasing inclination to 13º it may increase to 400kN in Figure 5(b). That exceeds the general force to attain 40tons that becomes the maximum. It means that the high rotation firstly and then heavy blade mass and radius has been arrived here. The parameters as radius R=8.7m, rotation n=500r/m and mass M=380kG in one helicopter. Thereby the small one may benefit from maximum for us to consider carefully in optimum design besides the high cost made by manufacturers. The minimum force has been one as seen in Figure 5(f) that is 130kN under radius of 7.7m, rotation of 300r/m and mass of 380kG in one blade of helicopter. If decreasing the inclination to 4º the better force may be formed with 3tons at the time of 1.7s that makes more reasonable one. The turn of effectiveness force has become as n>M>R in this study. Thereby that the short time as 0.25s is adopted to evaluate the force is more feasible here because of its normal force level. Here the one blade gravity has been adopted with 380kG because of its heavy power that dominates the biggest helicopter currently. Meantime the force may be loaded in one blade so that the total five blades one may become five times of the curve force in a helicopter. For example, propulsion force 3tons multiplies five times become 15tons in five blades of helicopter.

Figure 6: The relationship of various propulsion and angle with defined rotation speed n=300r/m and power P=2,566kW in one blade of helicopter.

Figure 6 shows that the propulsion force may increase as the angle f  increases in proportion. In detail, the former will arrive at 1.5kN as the angle f is 24º at most with rotation 300r/m and power 2,566kW in one blade of helicopter. The least one arrives 150N at angle f=2º therein the 750N force has been neglected in this condition. It has ten times increasing to 1.5kN i.e. 0.75tons at most with the angle f  increasing. Overview, the propulsion force may be attained through controlling rotation speed n and time t even angle f completely. Other parameters like inclination q, power P and blade gravity M has been modelled and discussed in details. The turn effectiveness has been n>M>R generally. Normally the propulsion force will become increased as increasing these parameters except rotation speed n with passive components and time t to be bigger than half periodic one.

Conclusions

The propulsion force may increase as the angle f  increases in proportion. The propulsion force may be attained through controlling rotation speed n and time t even angle f completely. Other parameters like inclination q, power P and blade gravity M has been modelled and discussed in details. The turn effectiveness has been n>M>R generally. Normally the propulsion force will become increased as increasing these parameters except rotation speed n with passive components and time t to be bigger than half periodic one.

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