United States. National Advisory Committee for Aer.

Annual report of the National Advisory Committee for Aeronautics online

. (page 57 of 77)
Online LibraryUnited States. National Advisory Committee for AerAnnual report of the National Advisory Committee for Aeronautics → online text (page 57 of 77)
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404 AEBOKAUTICS.

Subclass 12.& — Y dived fuel inlet "between air inlet valve and throt^
tle^ fuel val/i>e controlled independently by vacuum or air flow.— On
page 402 (838,085, Dec. 11, 1906, Cook) the fuel valve is operated
bv a diaphragm, while the air enters a series of spring check valves.
The flow itself lifts the flow disk and controls the lift of the metering
pin, on page 402 (918,607, Apr. 20, 1909, Sturses), air entering
through a nxed primary and an automatic secondary passage. Ac-
tion of the vacuum on a piston moves the fuel valve on page 402
(1,126,159, Jan. 26, 1915. Dressel), the fuel entering the air through
a nozzle in the path of tne stream from an automatic air valve.

Subclass i^.T, variable float oTurnnher j>ressy/re. — ^The combination
of a ^avity loaded automatic air valve actuating a long fuel meter-
ing pin, with ccHitrol of float chamber pressure by an adjustable air
flow through it to the mixing chamber, is illustrated on page 403.
(1,010,066, Nov. 28, 1911, Newcomb.) On page 403 (1,025,816, May
7, 1912, Lofthouse & Booty) there is shown an air inlet of gas holder
form with a mercury seal, the side walls having slots. Associated
with it to move simultaneously in the opposite direction is a fuel
tube sealed also in mercury and with fuel floating on the top. The
fuel escapes by gravity through a hole at whatever depth beneath
the surface may be fixed by the air bell. The fuel then rises with the
air. The float chamber pressure is equalized, so the fuel flow will be
purely by gravity head.

Class IS — Carburetors^ proportioning fow aspirating, single fuel
and multiple air inlets, both with regulating valves. — ^This is prac-
tically a modification of the common auxiliary air valve class by add-
ing to it a fuel valve, the action of which is expected to connect and
compensate for the deficiencies of the same combination without the
fuel valve and indicates a failure to accept the fixed fuel inlet with
its air- valve compensators as adequate.

Part of the air enters through an automatic valve leading^ to a
throttle-controlled port on page 409 (813,653, Feb. 27, 19067Tiaw),
part enters directly through one fixed inlet as primary air, and still
another part through anoflier fixed inlet as secondary air. The fuel
valve is controlled by the throttle that also controls such secondary
air as first enters through an automatic valve, a somewhat complex
combination. Also unusual is the arrangement on pages 409 and 410
(817.903, Apr. 17, 1906, Comstock), in which the ftiel valve deliver- ,
ing fuel to the primary air is controlled mechanically with the sec-
ondary air, the primary air carrying the fuel meets the secondary
diluting air at a distance where the two pipes join on top of the
engine. One of the stationary-engine schemes is illustrated on page
410 (876,519, Jan. 14, 1908^ Brothers), having a fixed primary air
inlet and a secondary air swing valve linked to a threaded fuel needle
valve, both being under governor control. It is difficult to see how
such an arrangement in the absence of a throttle could maintain any
definite proportionality, because as needle and secondary air valves
close, the vacuum on the primary air inlet must increase and its flow
as well.

A fixed primary air inlet and automatic secondary are associated
with a fuel valve that lifts directly with the vacuum acting on a
piston at its top on page 412. (1,132,934, Mar. 23, 1915, Heitger.)
Anotiiier power-driven-fan case, this time falling in the class of
single variable fuel and multiple variable air inlets, is shown on
page 410. (1,154,530, Sept. 21, 1915, Merriam & York.) The fuel



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AERONAUTICS. 405

needle valve, located in a fixed primary air Venturi throat, is regu-
lated by the speed of a fly-ball governor, which also adjusts simulta-
neously the secondary air. The mixture enters the fan casing at its
center and is discharged at a pressure in excess of atmosphere, but
proportionality will evidently vary with the engine inlet header pres-
sure, which is the fan back pressure whenever now changes without a
speed change. The torque produced by the air striking the curved
vanes of what would be an air turbine, were it free to rotate, causes
it to turn slightly on its screw-threaded stem, thereby controlling a
fuel valve, on page 412. (1,158,824, Oct 26, 1915, Smith.) An auto-
matic secondary air valve is provided.

A fixed primary with an automatic secondarjr air inlet combina-
tion has a fuel valve that opens by turning in its threaded casing,
the turning being caused by tne rise of a flow disk in the mixture path,
which rotates as it rises because of a helical rib engaging a notch on
its edge, the fuel valve stem being square is turned thereby. This is
shown on page 412. (1,178,064, Apr. 4, 1916. Fahmey.)

Subclass 13 J — valved fuel irdetj fixed primary air^ fixed or primary
secondary air inlets, throttle control of fuel inlet valve. — Fixed pri-
mary air passes upward around the regulating fuel valve and meets
secondary air entering through a tapered slot m the side of the cylin-
drical sleeve throttle is on page 411. (886,265, Apr. 28, 1908, Speed.)
A yoke from the throttle stem actuates a sliding cam ana roller gear for
moving the fuel valve. Rotation of a barrel sleeve thjx>ttle surroimd-
in^ the fuel inlet and a cross tube for primary air controls the sec-
ondary air by a port opposite to the throttle port and lifts the fuel
needle by an mclmed cam surface rotated under a lever attached to it
in the form on page 411. (950,423, Feb. 22, 1910, Anderson.) Two
fuel inlets, one nx^ and the other varying, are similarly located and
act as one, the fixed serving only to insure the accuracy of the open-
ing for idling, on paces 411 and 412. (976,258, Nov. 22, 1910, Gal-
lagher.) The throttlfe controls fuel needle and the secondary air
port. An example of a fuel needle placed at a distance ihrom the fuel
mlet nozzle is diown on page 413. (1,029,796, June 18, 1912, Daw-
son.) The nozzle is located in a fixed primary air inlet, and the
throttle controls a pair of secondary air ports and the fuel needle
valve. Location of the regulating needle valve in a tapered air
throat associated with a secondary sliding air sleeve beyond it, both
sleeve and needle being operated by linkage from a damper throttle
is illustrated on pages 413 and 414. (1,065,462, June 24, 1913, Mil-
ler.) A comparatively recent form of the rotating barrel sleeve
acting as both throttle and secondary air valves at opposite ports,
and carrying a fixed primary air inlet along the axis, the fuel needle
valve cam operated by the rotation, is shown on page 414. (1,126,839,
Jan. 19, 1915, Keizer.) Here the primary air throat lies wholly
within the barrel and is provided with a bend or side outlet shroud
on top.

As an example of the effect of change of time in improving form,
the same elements as were incorporated in figure 390 are again brought
together in a new structure on pages 414 and 415 (1,148,485, July 27,
1915, Gallagher) about five years later. Attention is called to the
substitution of a good form of tapered throat for the primary air
instead of the former irregular one with no definite direction and
maUng many eddy currents, the substitution of a damper for a lon-
gitudinal cylindrical throttle, a concentric for a side float chamber,



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406 ABBOKAUTIOS.

while retaininff a linkage between the secondary air. the fuel needle
and the throttle, and finally the separate low-speed tuel orifice.

JSubclaas lS£ - ^alved fuel inlet^ valved primary and secondary w
inlets^ throttle control of both air inlets and the fud inlet valver-
Again, the throttle is retained as the prime variable element of con-
trol, this time varying all areas with it, that of both of the air inl^
and the fuel, on the (Hd assumption that areas rather than pressares
are the fundamental variables in proportionality maintenance as

auantity varies, instead of giving due weight to both and using as
tie prime variable some unit that is a measure of flow.
On page 416 (1,134,366, Apr. 6, 1916, Barnes) a tapered throat is
provided with a central tapered plug, serving as a primary air valve
and sliding with the fuel needle on a fixed sleeve, and to it is con-
nected a secondary air sleeve, and this triple-moving member acts as
the throttle. The varying throat and fuel inlet relation itself acts as
a compensation factor in this case. A rotating barrel sleeve acts simi-
larly by controlling the outlets of both primair and secondary air
passages, the same motion varying the fuel needle portion on pages
416 and 417. (1,162,111, Nov. 80, 1916, Simpson.) The fuel inlet is
here set in front of the air restriction so that it receives less vacuum
than in the previous case.

Subclass ISJ—Vdlved fuel inlety fixed primary^ and throttle-^m^
troUed secondary air inlets^ fuel valve controlled by the vacuum cft
air flow independenUy. — Making the variable air depend on the
throttle and the fuel variation on the flow directlv is a good example
of mixed variables, because the two things that should vary together
might naturally be expected to receive their motion from the same
instead of different sourcea Two examples only are given on page
418 (1,081,222. Dec 9, 1913, Durr), having agam the double-ported
rotating barrel to serve as secondary air and throttle valve. It i&
however, screw threaded in its casing, so that it has a small axial
motion with rotation. A spring-resisted piston within it carries
the fuel valves and a fixed primary air passage passes through the
end of the casing and through the piston rod to the central fuel
opening. The fuel valve lifts an amount fixed by the spring tension
and the vacuum, and thereby regulates the fuel delivered to the

Srimary air, the amount of which is small. The old air impact flow
isk is used to control the fuel in a chamber supplied with fixed
Erimary and automatic secondary air arranged with an electric
eater to operate on kerosene, as shown on page 418. (1,181,157,
Mar. 9, 1916, Percival iSk Patterson.)

Subcktss 134 — Valved fuel inlets^ fixed prvmary and automatte
valved secondary air inlets^ fuel vcme controlled by the throttle,—
As the use of the automatic secondary air valve in place of throttle
control is a proper step, especially for the high capacibr variable
speed en^e, it seems questionable that the throttle should be selected
at the origin of fuel- valve regulation, but there are quite a number of
cases of this sort

A cam connection is provided between a damper throttle and the
fuel needle on page 419 (870,062, Nov. 5, 1907, Schebler) and ap-
plied to a carburetor of the common fixed primary and automatic
secondary air form. The fact that a fuel- valve adjustment is sug-
gested at all for a carburetor of this large old class is a measure of
lack of confidence in the adequacy of me OHnpensation it affords



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AEE0NAUTI08. 407

without t}ie fuel valve. Another case of cam-lifted fuel valve oper-
ated from a damper throttle in conjunction with a fixed primary
and automatic secondary air inlet is shown on page 419. (1,052^917,
Feb. 11, 1913, Heitger.) A combination of separated fuel-mlet
nozzle and regulating fuel valve, the latter operated from a damper
throttle and the former associated with a fixed primary and auto-
matic secondary air inlet, is shown on page 422. (1,096,669, May 12,
1914, Sharpneck.) The fixed primary and automatic secondary air
inlets are used in combination with the rotating sleeve throttle turn-
ing a screw-threaded fuel valve in its fixed casing, on page 422.
(1,106,226, Aug. 4, 1914, Lamb.) Use is made of the long taper fuel
metering pin fixed to a flat block form of throttle on page 420
(1,106,802, Aug. 11, 1914, Goldberg), in connection with nxS pri-
mary and automatic secondary air inlets, but in such a way as to
partially restrict the primarv air passage. On page 420 (1,173,762,
Feb. 29, 1916, Arquembourg), a regulating fuel valve cam operated
from the shaft of a barrel throttle is combined with a fuel nozzle
located in a Venturi throat, beyond which the secondary air enters
through ball-type automatic valvea

Subclass 13.6 — Valve fuel mlety -fixed primary and autamatie
valved secondary air inlets^ fuel valve controlled by the automatia
secondary air valve. — ^Assummg that the old standard fixed fuel and
primary air carburetor with automatic secondary air compensation
to be inadequate for the severe conditions of the variable-speed en-
gine, and that some additional means of compensation is necessary,
then it is quite a natural and logical step to make this take the form
of a fuel valve adjustment controlled by the secondary air valve on
the ground that up to the time the latter opens the fuel area should
vary with the additional air area, or that both areas should be con-
trolled by the vacuum. This seems to be the ori^n of the ideas of
the cases of this subclass, one of the earliest of which is that on page
421. (855,170, May 28, 1907, Gray.) A direct connection is made
between the automatic secondary air valve and the fuel valve, so
both move the same amount in this case. A bell-crank linkage is
provided to connect a horizontal-stem automatic air valve and a
vertical-stem fuel valve on page 421. (981,853, Jan. 17, 1911, Halla-
dav.) Location of the fuel needle on the axis of the automatic air
valve, the stem guide of which is tubular and serves as the fixed
primary air inlet, is illustrated on page 421. (1,010,185, Nov. 28,
1911, Schulz.) A tubular sleeve form of fuel valve, forming the
stem guide of the secondary air valve, is shown on page 4S1.
( 1,022 J02, Apr. 9, 1912, Bothe A Gulp.) A cam connection tetween
the automatic air valve and the fuel needle is shown on page 423
(1,078,590, Nov. 11, 1913, Muir), which also illustrates the idea of a
throttle limit to the movement, so that^ while it is automatic and
completely so for a wide-open throttle, it is not for a partly closed
throttle, and at any time closure of the throttle closes both fuel and
secondary air valves. Two fuel valves operated by the automatic
air valve are shown on pages 428 and 424 (1,111,224, Sept 22, 1914,
Hamilton), but so located as to act as one, so far as proportionality
is concerned. Of course, two different fuels can be simultaneously
used. A lever connection between the secondary air valve and the
fuel valve is shown on page 424 (1,118,126, Nov. 24, 1914, Harroun),
which also has electrical neating coils in the primary air tube in-



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408 ABB0KAUTIC8.

tended to adapt it to keroeene. It is of interest to oomparQ this with
the same proportionality arrangement adapted to use exhaust heat
both for warming the primary air and for directly heating the pri-
mary mixtures, as shown on page 424 (1,158,494, Nov. 2, 1915, Har-
roun), to which an air-valve da^pot is added as well.

Use of a very much restricted primary air venturi, as illustrated
on page 425 (^1,156,823. Oct. 12, 1915, Schebler), hardly more than
will serve to lift the luel and to somewhat spray it. This brings
this subclass very close, indeed^ to that of subclass 12.5, with all its
favorable functional characteristics; It is an excellent example of
the way in which one class merges into another, and necessarily so^
no matter what the classification basis may be.

Subclass 13.6 — Valved fuel inlet^ vcUved primary and secondary air
inlets^ both automatic, fuel valve controlled by one or both automatic
air inlet verves. — ^In essential principle this subclass is the same as
that of subclass 7.5, though structurally the difference is real, being
that of two valves versus cme. Of course, if the valves are different,
especially in size and loading, then control of the fuel valve does
not so directly proportion fuel to total air as with two similar valves
which would be equivalent to one. If one such valve will serve the

Eurpose, some other reason than a search for proportionality must
e responsible, and one reason that certainly applies in some cases
is a failure to realize the fact.

Two spring-loaded automatics, nearly similar, are used <m page
426 (917,125, Apr. 6, 1909, Pierce) , one of them controlling the fuel
valve by a cam surface on its stem« This one is fitted with a throttle
resistance, while the other is free. A pair of swing checks of differ-
ent size are both connected to a bell-crank needle- valve control, and
they therefore act as one on pase 426. (1,022^326, Apr. 2, 1912.
Namur.) Four small spring-loacfed secondaiy air valves are addea
to a central automatic piston sleeve primary automatic, controllinc^
the fuel-metering pin, on page 426. (1,084,954, Jan. 20, 1914, Nice.)
A single piston and sleeve form of automatic valve controls two sets
of air ports, the one above acting as secondary and a lower annual
port as primary air passage. The moving member adjusts the fuel
valve at the same time on page 427. (1,087,187, Feb. 17, 1914,
Schulz.) The primary air is small and is a convenient means of lift-
ing and spraying the fuel. The action is entirely equivalent func-
tionally to the previous class referred to. As arranged on pace 428
(1,105,134, July 28, 1914, Hanemann) the primary automanc air
valve controlling the fuel valve is entirelv different from the
secondary, and the action must also be different with respect to
proportionality.

Chi page 427 (1,125.525, Jan. 19, 1915, Hathcote, is shown a form
that again illustrates now closely one class merges into another, this
case being, except for the proportion of the fixed to the valve con-
trolled air, similar to those of subclass 12.5 more especially those
examples of that class that have a small fixed air passage passing the
fuel inlet for idling and for lifting the fuel into the main air stream,
but not enough air to be consider^ as removing complete air control
from the automatic valve. Here the central fixed hole is too large to
be ignored in this way, but it would be impossible to draw a line of
division with precision.



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ABBONATTTICffik 429

Class Hr-^arhwretars^ proportiomnff fioWj aspirating^ multiple
fuel ani air inlets^ both with regvlatmg valves. — It would seem as
if sufficient compensation could be secured by regulating fuel to air,
or air to fuel, and certainly the opportunities are ffreat with air and
fuel both regulated even when there is only one imet for each, with-
out adopting a multiplicity of such, yet this is done in the cases of
this class. However, the situation is not as complex as it might seem,
because in the first place there are not many such cases, and second,
these all fall into two groups, the high ana low speed ^oup or the
multiple duplicate carburetor group, each of which constitutes a sub-
class.

On page 428 (1,123,508, Jan. 5, 1915, Farrell), a series of five fuel
needles is arran^d across an air passage, and they are operated from
a single rocker 3iaft by lever arms set at slightly different angles, so



Online LibraryUnited States. National Advisory Committee for AerAnnual report of the National Advisory Committee for Aeronautics → online text (page 57 of 77)