numbers of vanes 35 are utilizable herein as the disk 15 and the vanes 35 rotate areas of variable size are created between the vanes 35 as shown in the figure there are 14 zones designated from a to n as will be discussed herein zones a b and c which all have the same or similar area form an outlet zone o zone b is in register with an outlet 45 of outlet zone o similarly zones h i and j which all have the same or similar area form a similar outlet zone p where zone i is in register with outlet 45 of outlet zone p in outlet zone o and outlet zone p the vanes 35 in register therewith are in a stowed position within the relevant slots 30 as they follow first contour 50 in the cam surface 25 the first contour 50 of the cam surface 25 in outlet zone p has a constant length radius 55 emanating from axis 20 the area of zones a b and c and the area of zones h i j is minimized and carry compressed fluid such as air therein zones d and k form compression zones as the variable vanes 35 move from an extended position relative to the slots 30 to a stowed position while following a diminishing second contour 60 thereby limiting e g diminishing the area of zones d and k to the same area shown in zones a b and c forming outlet zone o and zones h i and j forming outlet zone p respectively.