Accession Number : AD0632398

Title :   THE EFFECT OF CAMBER ON THE NEAR-SURFACE FORCE, CENTER-OF-PRESSURE, AND VERTICAL STABILITY CHARACTERISTICS OF A RECTANGULAR -PLANFORM HYDROSKI.

Descriptive Note : Letter rept.,

Corporate Author : DAVIDSON LAB STEVENS INST OF TECH HOBOKEN N J

Personal Author(s) : Van Dyck,R. L.

Report Date : DEC 1965

Pagination or Media Count : 23

Abstract : The hydrodynamic force characteristics of a cambered rectangular planform, 15-degree deadrise hydroski are shown to be similar to those of an equivalent uncambered ski with the exceptions that, for a cambered ski: (1) the zero lift angle is shifted to lower angle of attack for the same wetted area and aspect ratio and (2) the center of pressure is shifted aft. Comparison at the same draft -- or wetted area and aspect ratio -- show similar submerged lift-drag ratios for both cambered and uncambered skis in the range of trim angles tested. The region of pre-emergence vertical instability is shown to be caused by the loss in lift as a hydroski runs in the range of drafts just below the planing boundary down to drafts sufficiently deep to preclude ventilation and surface effects, where a ski can run stable fully-wetted with approximately double the planing lift. Increased forward acceleration at unporting was found to shift the pre -emergence instability range to higher speeds and to reduce the time interval spent in this unstable region. (Author)

Descriptors :   (*CAMBER, HYDROSKIS), (*HYDROSKIS, SEAPLANES), FORCE(MECHANICS), PRESSURE, STABILITY, LIFT, DRAG, SURFACES, VELOCITY, HYDRODYNAMICS

Subject Categories : Aircraft
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE