| 摘要 |
An airborne craft with at least four propellers arranged in a front propeller pair and a rear propeller pair having substantial vertical or forwardly inclined axes has hydraulic motors which drive the propellers. A pumping device supplies two pairs of separated flows to the motors. One pair of the flows has fixed delivery and equal flow quantities per revolution of the pump while the other pair has variable flow-rates but the flow quantities of both flows of the variable flow pair are also equal relatively to each other. One of the flow pairs drives the front propellers at equal speeds and the other pair of flows drives the rear propellers with equal speeds. But the variability of the rates of flow of one of the pairs of flows is utilized to let one of the pairs run with a different rotary velocity of the propellers than the other pair. The so obtained difference of rotary speeds of the propeller pairs relatively to each other is utilized to incline the vehicle in a desired and controlable extent in the desired direction of flight to obtain and control the forward speed of the vehicle. The variable flow pair has a common control means which assures an equality of the rates of flows in the variable flow pair, whereby a straight forward flight path of the vehicle is assured and departures to the right or left of the desired flight path are prevented. The invention also makes it possible to set the arrangement to the most effective and fuel saving speed as well as to employ control means, which prevent too stiff descents or ascents. In the specific embodiment whereto the claims are directed, the invention is utilized to provide a vehicle with the lateral size of a passenger car to be able to run on the road and lift away from it to fly through the air, borne by eight propellers which are located and revolve in eight ducts.
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