The models designated "Torino 30, 31, 32" are horizontal tail surfaces of rectangular, triangular, and elliptical plan form and all of the same profile section. Tests were carried out with the object being to determine the effect of the propeller slipstream on the aerodynamical characteristics of the horizontal stabilizer. The results presented correspond to a first series of tests made without an interposed wing and in which the distance between the plane of the propeller disk and the tail was maintained constant.

Test equipment is described that includes a system of three quartz indicators whereby three different pressures could be synchronized and simultaneously recorded on a single oscillogram. This equipment was used to test the reliction of waves at ends of valve spring, the dynamical stress of the valve spring for a single lift of the valve, and measurement of the curve of the cam tested. Other tests included simultaneous recording of the stress at both ends of the spring, spring oscillation during a single lift as a function of speed, computation of amplitude of oscillation for a single lift by harmonic analysis, effect of cam profile, the setting up of resonance, and forced spring oscillation with damping.

The apparatus consists of a universal balance with transmission at variable speeds from 300 to 5,000 rpm and a group directly coupled to the model for speeds of 5 to 30,000 revolutions. This new apparatus was also designed with a torsion meter for measuring the torque. Tests were conducted on the effect of the angle between the propeller axis and the wind direction. The results presented correspond to a first series of tests made without an interposed wing and in which the distance between the plane of the propeller disk and the tail was maintained constant.

This investigation was intended to throw light on a number of problems: 1) obtain a time history of the force acting on the gear wheels during take-off and landing runs; 2) obtain the time history of the direction of this force (magnitude of its three components along the coordinate axes); 3) derive conclusions as to the design load factors. In connection with the latter, of special interest was the solution of such problems as: a) the dynamic loads in the three main landing attitudes; b) the problem of the true direction of the forces for each of the three "pure" types of landing; c) combination of the above types; d) the comparison for each of the chassis members of the computed force (according to the design standards) with the actual force measured in the tests so as to determine the actual factors of safety.