FIFTY YEARS OF FLYING PROGRESS — LOENING 211 



contemplates other cargo types that have a large swept-up fuselage 

 with a very high tail, the strength of the fuselage being tremendously 

 weakened by the cutting out of a large door right in the center where 

 torsional strength is needed. To resist tail flutter and carry the high- 

 tail-twisting loads, a very heavy fuselage framing is needed to make up 

 for the door-hole weakening. 



As soon as the wing-warping lateral-control system used by the 

 Wrights and by Bleriot disclosed how it weakened the wing structure 

 and what heavy loads it put on the control system, it gave way to the 

 use, at first, of separate surfaces in between the two wings, like the early 

 Curtiss ailerons and the ailerons that Glenn Martin mounted on his 

 first and very successful tractor airplane. In the first few years of 

 flying development, even the elevators and the rudders were quite 

 widely used in a balanced single-surface form. Then when these gave 

 way to the fixed stabilizer and trailing elevator and to the fixed fin and 

 trailing rudder, it was not long — about 1909— before Moore-Brabizon 

 in England, Farman in France, and several others both in Europe and 

 America obtained their lateral control from hinged flaps cut out of the 

 wing tip. These controls have survived ever since, and had every 

 right to continue to survive as they were eminently correct and prac- 

 tical and were easily modified to have mass or aerodynamic balances so 

 that they could grow to large size and still be workable. 



However, as soon as we entered the transsonic and supersonic area 

 of flight, aircraft controls by movable hinged-surface areas became 

 open to a great deal of question. Lateral control had already been 

 toyed with in the form of spoilers that would reduce the lift on one 

 side only. But the problem of control in the supersonic region still 

 remains. It is fairly certain now that control by hinged flap is apt 

 to be superseded by something else. 



Although we are principally concerned here with our 50 years of 

 fixed-wing aircraft development, control and stability problems are 

 plaguing helicopter development to a very considerable degree. It 

 may be that helicopters will have to adopt a three-rotor system giving 

 three points of control, like the two wings and the fixed tail of the 

 Wright airplane, and then merely vary the thrust of the rotors against 

 each other to get any combination of control forces around the three 

 axes. 



LANDING GEARS 



The landing gears of aircraft have gone through a complete cycle in 

 these 50 years. The Wrights started with skids alone, and the classiest 

 new designs of aircraft today again look like skids alone. The story 

 of this metamorphosis is about like this : The Wrights started with 

 skids alone, because their feeble craft could not carry the added weight 

 of wheels, nor had it enough horsepower to overcome the wheel friction, 



