<DOC>
<DOCNO>
792
</DOCNO>
<TITLE>
some low speed problems of high speed aircraft .
</TITLE>
<AUTHOR>
spence, a. and clean, d.
</AUTHOR>
<BIBLIO>
j. royal aero. soc. v. 66, april 1962, pp 211-225 .
</BIBLIO>
<TEXT>
the first part of the paper deals with the low speed aerodynamics of
aircraft shapes suggested by kuchemann, at the second international
congress in aeronautical sciences at zurich in 1960, as suitable for
achieving a required range at supersonic speeds, namely wingbody
arrangements with sweepback angles of 55degrees or 60degrees and
streamwise thickness-chord ratio of about 5 per cent suitable for low
supersonic speed, and slender near-triangular wings with sharp leading
edges suitable for mach numbers of about 2 or more .
no attention is given to /slewed/ wings, powered lift or variable geometry
.
in dealing briefly with swept wings, the need for avoiding separation of
 flow from the leading edge is demonstrated, with the conclusion that it
 is desirable to use leading edge flaps with blowing or suction at the
knee together with blown trailing edge flaps . wind tunnel tests are
described on a simplified model with these boundary layer control
methods applied . mention is made of the possibility of adverse ground
effect on maximum lift .
more attention is given to the case of slender wings because their use
involves a new type of flow with separation from all edges . this flow
and its steadiness are therefore discussed from the point of view of
the possibility of buffeting,. the effect of plan form on static
longitudinal stability and pitch-up is analysed,. and a short summary of
 available results on damping in pitch is given . large rolling moments
due to sideslip are shown to give rise to serious problems of control,
and the present state of knowledge of static lateral and directional
stability and rolling and yawing rotary derivatives is discussed .
finally the effects of proximity to the ground are summarised .
the second part of the paper is concerned with work aimed at clarifying
some of the requirements for handling qualities of future aircraft . it
is not so much concerned with forecasts of the dynamic behaviour of
these future aircraft as with determining what the pilot wants .
two aspects of control in the vertical plane are discussed in some
detail namely speed control and glide path holding . flight tests on an
avro 707a aircraft, with artificially worsened characteristics, are described,
and it is shown that substantially constant performance in the
piloting task can be achieved at the expense of increased pilot effort .
 some tentative conclusions on desirable levels of speed stability and
phugoid damping are, nevertheless, drawn .
a brief review of the present status of lateral/directional handling
requirements, using mainly american data, is also included .
</TEXT>
</DOC>
