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National Advisory Committee for Aeronautics, Technical Notes - The Effect of Tip Shields on a Horizontal Tail Surface

A series of experiments made in the wind tunnel of The
Daniel Guggenheim School of Aeronautics, New York UniVersity,
on the effect of tip shields on a horizontal tail surface are
described and discussed. It was found that some aerodynamic
gain can be obtained by the use of tip shields though it is
considered doubtful whether their use would be practical.

It is a well~known fact that every wing or lifting surface
experiences certain lift losses at the tips. The tip vortices
that accompany the loss of lift are at the same time a source
of a great portion of the wing drag. Any method reducing this
loss of lift and this increase in drag improves the aerodynag;§nd
efficiency of the system. From previous experiments it has been/
that these tip vortices can be reduced by the use of shields at
the tips. Experiments of this nature have been carried out at

GBttingen (Reference 1), Langley Memorial Aeronautical Laboratory
(Reference 2), and the Daniel Guggenheim School of Aeronautics,
New York University. A theoretical consideration of the drag
effect of shielding the tips of wings has been made by Hemke
(Reference 5).

This paper describes_some recent experiments at The Daniel
Guggenheim School of Aeronautics, New York University, to deter—
mine the effect of shields on horizontal tail surfaces. The lift
and drag forces were measured at various angle settings of a sta-
bilizer and eleVator with and without tip shields (vertical).

The horizontal tail surface model used in these tests had
a symmetrical cross section slightly over 15 per cent of the
chord in thickness (See Figs. 1 and 2). The span was 18 in.
and the chord 6 in. It was equipped with an elevator 2—1/8 in.
(35.4 per cent chord) wide. The area of the entire model was
0.75 sq.ft., of which the eleVator was 35.4 per cent. The tip
shields were made of brass of the form and dimensions shown in
the above figures. The general shape of the shields used in
these tests was adopted because in an earlier series of tests
this shape gave the.best results. 'The detailed features shown
were necessary to prevent leakage and to allow motion of the
elevator