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128    HELICOPTER AIR SERVICE PROGRAM

rotates through 90 degrees, as you would expect, the control of the airplane must phase from the normal collection of ailerons and rudders and elevators to a different set of controls in order to control about all three of its axes. 

For example, as the wing comes up, the control actually changes over from the rudder to the ailerons to control the yaw; from the ailerons to the propellers, the differential propeller pitch supplying the rolling moments for control of the yaw and roll, and the tail rotor comes into being and controls it in pitch. 

In addition, we have an integral cross-shafting arrangement through the wing to the T-box in the center of the wing. This allows the airplane to have all four propellers in operation and equal power distributed over the propellers regardless of the number of engines in operation. The tail propeller is driven by a shaft receiving its power from the T-gear box. 

The normal cruise configuration for the airplane, for example, is with two engines operating and all four propellers turning. At this cruise configuration, the normal cruise speed is about 300 miles an hour. Maximum speed is in excess of 400 miles an hour. 

Before I go any further, I would like to call your attention to the charts we have on my left and which are a physical comparison of the XC-142 with the well known DC-3. The one that Walt Hesse is standing beside now is the current airplane as you see it, which was configured for 40 passengers, and as it stands you can see it is shorter than the DC-3. It has a smaller wing span, but, in fact, it has a larger cargo compartment. 

I think it is interesting to note that the way the airplane-the parameters that really dictated the design of the airplane are the size of the cargo compartment and the original Navy requirement. 

By that, the cargo compartment in the specification was dictated as being 30 feet long, 7 1/2 feet wide, 7 feet high, and it could not be violated. 

The Navy requirement at the time, because of the physical restrictions on their carriers, dictated that we contain this in a little over a 30-foot folded width and a length and height which were compatible with their physical restrictions. So, in effect, they gave us a big box with a little box inside of it, and said, "Design an airplane which will fit outside of the little one and inside of the big one." 

The chart on my far left is a modification of the airplane where we, in effect, put in a 9-foot extension at some point in the symmetrical section of the airplane and which increases the passenger capacity from 40 to 52. 

Senator MONRONEY. Nine-foot plug?

Mr. THAYER. Nine-foot plug. I think we could-I am sure we could-expand that beyond 52 passengers, depending on the degree of comfort required with a short haul type of operation like this. There are other seat arrangements which we are looking at which may give us upward of 60 passengers. 

Senator MONRONEY. You have the capacity, do you not, Doctor, to lift that many people. It is just a matter of putting in the comfortable seat arrangements?

Mr. THAYER. Frankly, Senator, if we added a 9-foot plug and added more people, we would have to call upon the engine manufacturer to give us a little more thrust.