Project Sign Progress Report, 1948

\ I
THE
AEROPLANE 186 FEBRUARY 13, 1948
C..HlUr
of the
"well-tried
"
co
nvention, .. normal " wings.
For
the c reasons. a study
of.
the hi\lory
of
the
u'IC
of
low
asp,.-ct. rat,o) m wing
de:.11n
will
be
of
interest.
Sp1ruually, the fathers
of
uch acronauucal
exhibits were
Ens!"hmen
. 1
hey
were people
of
good reputation ttnd
by
no
_me.ins suspect
o(
aerodynamic perversion.
F. W. Lanchcstcr was
undoubtedlf
the first acrodynamici,t
to
g,~e thought
to
aeroplane
winis
ot
circular
or
squ.irc
,hapc.
lo ht) bool.. publl\hcd m 1907,
he
referred c'tperiment th.it we lent aspect ratio.
hope
to
repeat u ,U a later date
on
a more
..c:1ent
ific levcl.- Eo.) In common with circular wing,.
annular
wings have the
fh
e conven11onal aeroplJne " constituted
of
two ba\ic aero remarl..able property that the lift force ,teadily increases with
frnh
: a
"ing
(,,
h1ch
,upp
l
1e~
the lift) and
ri
tail
(,,
hich balances incidence up
to
fairly high values without a stall.
For
all
and ~tabilize~ the wing). We I.now that \Uch a n arrangement I.n
o"
n arrangements the maximum lift
seem,
10 occ
ur
at
o.f
the
111.0
aerofoil compnnenh
i,
by
no
mean, the only pos incidences exceeding 30 degree,.
A, ,uch
h igh angle~
of
\tblc one.
The
balancing .ind st11b1lmng aerofoil (tailplane) incidence are not likely
10
be reached
an fl
ight unintentionally.
need not to be aft
of
the lifting wing
a,
a tail. It can be
It
1s
obv1ou,
"hy
annular wings have become renowned
forarranged anywhere
1n
relation to the wing. e.g .. above It,
belo11.
their good-natured flying charac1eri,1il:,.
it. o r in front of it. Another property of annular
wings (first establi,hed by
If the balancing aerofoil
i,
in front o f the main win~. the aero Tilghman Richard,)
i,
that the centre of pre,sure
of
,uch
wing
plane
i~
of the tail-first type. and if it
i,
attached to the
,y,tcm, i,
nearly stationary in flight ,
or
that a travel o f the
centre
of pre,wre can be obtained which
i,
po,itively stable
unul incidences o f the
order
of
18
degree
are
reached. In
fact. no case
of
longitudmal in,tabihty
ha, ever
been reponcd
w11h
an annular wing. although the centre
of
gravity has often
been located d:ingerou,ly far back.
The fi~t annular-wing aeroplane dates bacl.. 10 1908. Ith,1d little succe\\. Two type,
11.ere
con~tructed m ,ucces\ion
tu the de,1gns
of
a capable German aeronautical engineer, Fritz
Huth. who
"as
by profe\\1on a teacher at a technical ,;chool
( f-tg,. 4 and
61.
The ,econd type. which had a less elaborate
a1r,crcw drive.
fl
ew in May. 1910: it wa,. however.
,o
devoid
of
performance. in spite
of
a
SO
b.h.p. engine. that it was soon
,1f1e
rv.ards d1..carded as a hopeless proposition.
Britain'~ Fir..1 Doughnut
The Bri11,h concepuon of the idea has been for more
,ucccs,ful. A, it i, cun,1i1u1ed, until now. the best tried
reprc,cntativc. it~ hi,1ory may be given somewhat more
c,1cn,1vcly.
Ihe ori~mal idea for an annular-wing aeroplane came from
(,. A K itchen. m about 1910; he con,tructed a b1pl.1ne with
Fig. S. Kitchen's doughnut of 1911 . rini:-,haped wmg,, but made no progrcs, "ith it. The stableNND 927545