A rotary vane engine is a new type of internal combustion engine having more combustion chambers in comparison to common engines; more combustion would be caused by it in each revolution of the crankshaft. Therefore a high amount of power can be generated while the mass of this engine is less than others. A rotary vane engine consists of four main parts including rotor, cams, vanes, and housing. Some of the critical points in designing this engine include the determination of the optimum number of vanes and thermal issues; it should be mentioned that little research has been performed in this field in previous publications. Generating a proper path for the vane to move freely on the cams and control stress where vanes contact cams, is another important factor in the design of this kind of engine because its operating speed is about 7000 rpm. Vane’s acceleration resulting from cam profile would lead to an inertia force in vanes; this force would have an impact on cams and also would lead to stress generation. Therefore, the less acceleration is created in the blades, the fewer stresses will be, which the results show that with a decrease of 3.7% acceleration, the stress is reduced by 12%. In this paper, we study the different curves that are used in the construction of the cams, and the best curve in terms of lower acceleration, momentum, and stress created in the engine, as well as a higher compression ratio. Is selected. In addition to the curve of the cams, the mass of the blade also plays an important role in creating stress, and its lightness reduces the stress in the set of cams and blades. To reduce the mass, two methods of changing the sex and hollowing the blade are used. The results show that by changing the blade material from steel to titanium, the stress is reduced by 29%, and by hollowing the blade, the stress is reduced by 24%.