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Патент USA US2411484

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Nqvyls, 1946.
M, WATTER
'
2,411,484
AIR SPEED INDICATOR
Filed June 9, 1944
2 Sheets-Sheet 1
Nov. 19, 1946._
2,41 1,484
M.’ WATTER ‘
AIR SPEED INDICATOR
Filed June 9-, 1944
2 Sheets-Sheet 2’
_
,
INVHVTOR
Michael Wane);
ATTORNEY
Patented Nay. 19, 1946
'
r
2,411,484
[TED STATES PATENT OFFEQE
2,411,484
AIR SPEED INDICATOR
vMichael Watter, Philadelphia, Pa., asslgnor to
The Budd Company, Philadelphia, Pa., a cor
poration oi’ Pennsylvania
‘
Application June 9, 1944, Serial No. 539,437
3' Claims. (Cl. 73-182)
2
r
leads to the airspeed indicator
instrument
I 6 in
This invention relates to airspeed indicators,
as for use on aircraft and the like, and has for an
the pilot's compartment, thus canceling the ef
object the‘ provision of improvements in this art.
fects of-cross currents and turns. The dynamic
One
of
the
particular
objects
is
‘to
provide
an
head
ll isconnected
to the instrument“ by' a
air speed indicator which does not impose para- 5 tube ll.
'
sitic drag on the vehicle on which it is mounted.
As shown in Fig. 2, the dynamic head. II is
Another object is to provide ready access to all
parts of the apparatus at all times.
located in a recess It! in the nose and is remova
bly secured therein as by screws or bolts l9 in
Anothenobiect is to cancel out the effects of
side currents and turns.
the base. A heating coil 20, interior or exterior
_
10 of the external tube, is provided. to prevent icing
Other objects and advantages will be apparent
over. A drain 2| m'ay be provided for removing
from the following description of illustrative
water, if needed,
‘
embodiments thereof, reference being ‘made to. I As shown in Fig. 3, the static head [2 is formed
‘the accompanying drawings, wherein:
as a hole in a reinforced patch 22 on the nose
Fig. 1 is a perspective view of an airplane‘ 15 skin sheet, together with a, mating apertured
equipped with this airspeed indicator;
- - nipple ?tting plate 23 secured thereto.’ Pipe
‘ Fig. 2 is an enlarged section through the dy?ttings, including a union, and a removable box
namic head or Pitot tube;
cover 24 provide access to the outer aperture in
Fig. 3 is an enlarged section through the static
the skin for cleaning when necessary. Heating
head;
20 means 25 located adjacent the outer skin serves
Fig. 4 is a perspective view of a modi?cation;
to prevent ice forming over the aperture, though
and
at
thisatlocation
the danger of icing' is much less
Fig. 5 is a horizontal section. through the body
than
the nose.
‘
nose of Fig. 4 showing dual instrument tubes.
As shown in Figs. 4 and 5. the Pitot tubes ll’
Referring to the drawings, the vehicle here 25 for registering dynamic pressure may extend a
shown is an airplane A, including fuselage B;
short distance beyond the nose instead of being
wings C, empennage D, and outboard motors E
recessed into the nose as in Fig. 2. Two such
a, dynamic Pitot tube head it igplaced in the 30 pilot. Also the static tube heads‘ M’ are located
of the Pitot tube and the air ?owing away from
man tube or manifold Ida ‘which connects by
the tube head in all directions._ Heretofore, it 35 tubes 15' with the instruments it’. Thus while
has been proposed to place a dynamic tube head
the dynamic heads serve each instrument sepa
in the leading edge of the wings or other susrately, the static heads serve both instruments
tentation airfoil but the narrow edge is ailected
in common.
too much by shifting currents and climb angle
The axis of the dynamic tube is inclineddown
' changes to furnish accurate indications. Other 40 wardly toward the front end, here about~9°,'rela
installations have placed the dynamic and static
tube heads on a pedestal or outboard projection
tive to the fuselage axis.
,
‘
The bulbous front end of the fuselage is so
on either the body or sustentation airfoils but
deep vertically and so wide horizontally that the
this imposed undesired parasitic drag on the
mid-portion is substantially unaffected by air dis
airplane.
‘
45 turbances, hence the mid-portion of' the front
The static tube head i2 is placed on the side
end of the fuselage provides a good location‘for
of the body in a position where the air?ow is
the dynamic head of the air speed indicator, as
dynamic pressure or eddy currents. In Fig. 1 it
of a wing which is relatively thin vertically and
is placed on the rounded side of the nose, the 50 where changes in the angle of attack greatly
optimum point being determined by wind tunnel
tests or experiment for each particular craft. It
‘ is tobe noted that there is a static tube head 12
on each side of the body and that both a're con-
use
change the air conditions for a static head which
'may be there located.
-
'
It is thus seen that the invention provides ac
curate and accessible means for registering the
by tubes it to a common tube id‘whioh 55 airspeed; also that the minimum parasitic drag
2,411,484
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'
is imposed: and further that the eilects of side?
While certain embodiments of the invention
‘have been described, it is to be understood that
there may be various embodiments within the
' limits of the prior art and the scope of the sub
'
'
of said heads being attached to the shell of the
What is claimed is:
3
1. In an airplane having a fuselage which at
the front end is so deep vertically as to be sub 10
those which affect the leading edge of a wing with
changes in the angle of attack, and which front
end is disposed clear 01' the propeller stream, the
combination therewith of a dynamic head located
near the mid-height of the front end of the fu
selage, a static head located in each side. of the
fuselage, a pressure differential indicating in
strument located in said fuselage, and means for
conveying effects of air pressure from said dy
namic and static heads to said instrument.
2. In an airplane having a fuselage which at
the front end is so -deep vertically as to be sub
‘
_
I dynamic
and static heads torsaid instrument, all
-
stantially unaffected by air disturbances such as
4
the fuselage, a static head located in each side
of the fuselage, a pressure differential indicating
instrument located in said fuselage, and means
' for conveying effects of air pressure from said
currents and turns are eliminate .
joined claims.
i
the combination ‘therewith of a dynamic head
located near the mid-height 0f ‘the front end of
'3
fuselageiand being removable toward the inside
of the shell.
l
'
'
3. ‘In an .airplane having a fuselage which at
the ‘frontend is so deep vertically as to be sub
stantially‘una?ected by air disturbances such as
‘those which _‘ affect the leading edge of a wing
with changes in the angle- of attack, and which
front end is disposed clear of the propeller stream,
the combination therewith of a dynamic head lo
cated near the mid-height of the front end of the
fuselage, a static head located in each side of
the fuselage, a pressure differential indicating in
20
strument located in said fuselage, and means for,‘
conveying effects of air pressure from said dy
namic and static heads to said instrument, said‘
‘heads being located wholly within the airfoil sur
stantially unaffected by air disturbances such as
face of the shell of said fuselage.
those which affect the leading edge of a wing 2.5
with changes in the angle of attack, and which‘
MICHAEL vWA'I'I‘ER.
front end is disposed clear of the propeller stream,
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