**Fig. 11 The major factors raising efficiency of the lifting systems**

So far as the Vortical Lift-Propelled System develops an idea of the Airscrew-in- Ring, in the first approximation the major factors, raising of a propelled and economic efficiency were appreciated (Fig.11)

- A jet for the isolated lifting airscrew (Fig. 11-A) has inductive speed V2 twice more than suck in speed V1, therefore the cross-section of a resisted jet for the airscrew twice is less than area by swept the airscrew and diameter of the Airscrew in Ring will be in SQRT( 2) = 1,41 time less than at the isolated airscrew;
- At same diameter the system the Airscrew in Ring can be made co-axial and its thrust thus will be increased almost in 2 times. In view of interaction, it reduces diameter of its airscrews yet in 1,3 time. Therefore effective diameter of the hypothetical co-axial system the Airscrew- in-Ring, substituting the isolated lifting airscrew, will be in 1,41 * 1,3 = 1,81 less latter;
- At realization offered the RTC VZLYOT’s ideas of “Allocated” and “Limiting” airscrews 8, is possible, saving an equal maximum speed of throw out, to reduce the swept area yet about twice. Diameter thus decreases in (1,81 x 1,41) = 2,6 times and the level of a specific thrust on the worked area shouldtheoretically increase in 2,62 = 6,76 times. The realization of an idea of the “Overlimiting” airscrew (an epure 9), prospective in the Vortical Lift-Propellent System, at equal thrusts allows in a much greater degree to reduce its overall dimensions.

Therefore the Systems of the “Allocated” and “Limiting” airscrews allow essentially to reduce the swept area. For the comparative analysis in quality the fundamentals was taken the transport helicopter (Fig. 12) and even quantity (8 times) the lifting vortical devices. Their external diameter (Dę) was selected from a condition of maintenance the indicated above computational relation of the summarized area of all modules to the swept area of the initial lifting airscrew at equal computational thrusts. For increase of safety at refusal of one engine, fourSteam-Gas Turbines aggregates 1, 2 are used each of which maintains on two Vortical Modules.

**Fig. 12 “Classical” Vihrelyot**

The group of main modules 3 is motionlessly fixed on a centreplane 8, to two beams of which can if necessary be joint the additional modules 7 or wing 9. The group of the tail modules 4 is made turn 5 on 90o with the purpose of use them as propelled in cruise flight. The additional modules 7 increasing thrust at take of on20 %, actually increase of a loading ability of the vihrelyot twice. It is necessary to underline that the aircraft having maximum speed of throw out of equal same speed as at the initial lifting airscrew 10 has twice smaller effective diameter 11, ensuring its long hovering.

At fulfilment of transport works on longerons of the centreplane 8 can be establish additional wings 9 which at reaching of determined speed of flight create full lift. Thus the modules of the main group 3 are closed leafs 6 and the modules of the tail group 4 turn on 90o and create only propellent force, i.e. work as traditional airscrews. The economic parameters of the Vihrelyot and conventional commercial plane in this case are practically commensurable.