DECEMBER 20, 1917.
it
As illustrated in the diagrammatic drawing of the
petrol system, a supplementary petrol system is
used, employing an auxiliary petrol tank and a semirotary hand pump in conjunction with the main
system. I
Two three-way cocks are fitted, as shown, which
allow any one of the following three systems t o be
used, viz. :—
(a) Main petrol pump from main tank.
(b) From main tank by hand pump.
(c) By hand pump from auxiliary tank.
The driving spindle of the petrol pump also drives
a vertical spindle through small bevel gearing, which
operates the interrupter gear for the machine guns.
To the rear end of the pump spindle is fitted the
flexible tachometer drive.
In the earlier types of petrol pumps fitted to the
Benz engines, the castor oil chamber was provided
with an oil-filling cup. This was screwed into the
side of the chamber casting, and was fitted with a
special form of drain cock t o determine the quantity
of oil poured into the pump. This filling arrangement
has now been given up and the annular oil chamber
fitted with a drain plug only. The speed ratio of the
driving spindle t o the small crankshaft driving the
piston of the petrol pump equals 10.75 t o 1.
The bore of the pump equals 40 mm. and stroke
equals 26 mm. Lift of valves (inlet and outlet)
equals 2 mm. Volume of petrol delivered at each
stroke of pump equals approximately 2 cub. ins.
10 minutes with the piston in direct contact with the
petrol, with no deleterious effect.
A number of tests have been carried out to determine the rate of flow, also the inlet and outlet pressures of the pump, while tilted at the angles which are
likely to occur when the machine is in flight while
banking to the right and left, diving and climbing.
Readings obtained as a result of the tests are tabulated on following page.
The accompanying graphs (Figs. 26 and 27) show :—
(i) The delivery of the pump over a certain range
of speeds, the angles denoting the positions at which
the pump was set.
(ii) The delivery at constant revolutions while
working at angles of plus or minus 60°.
The maximum delivery obtained from the pump
was 288 pints per hour. This was obtained at a
pressure of 10 lbs. per square inch when the pump
was vertical and running at 850 r.p.m. In no case
does the delivery fall below 160 pints per hour. A
test was also carried out on the pump without castor
oil. Under these conditions the pump was run
successfully for about ten minutes, after which the
test was stopped.
R.A.F.
REPORT ON CHEMICAL ANALYSIS OF PARTS OF 230 H.P.
BENZ ENGINE.
Water
jacket
Crankshaft
Connecting
rod . .
Gear wheel
Camshaft
Inlet valve
Valve
spring
I
6
o
Ag
%
"I/o
O.35
O.48
/l
O.246
O.O26
.0027
.0014
O.I5 O.2I O.O27
0.23 O.25 O.OI4
O.I4 O.23 O.029
O.26 O.28 O.OI2
.0026
.0027
.0026
.0020
o-37
o-53
0.95
.0085
0.55
O.O7
O.I3
.040
/o
0.03
0.31
0.02 0.033
a
03
82
0.40
7.
"I
Ia
Nil
3.21
4.02
3.58
4.68
s.36
Nil
0.02
0.87
1.21
0.81
1.48
1.06
0.01
Graphitic Combined
Phos- ManCarbon. Carbon. Silicon. Sulphur, phorus. ganese.
"I
Cylinder
Piston
The weight of the complete petrol pump equals
6.75 lbs.
Test results of this petrol pump carried out recently
at the Royal Aircraft Factory are given in the following report :—
Effect of Angle.—-The normal consumption of this
engine is approximately 150 pints per hour at normal
speed, and the pump has a greater delivery than this
at any angle up to 60 ° in any direction.
Delivery.—Maximum: 288 pints per hour at
10 lbs. per square inch pressure when the pump was
vertical and running at 850 r.p.m. At normal speed,
i.e., 700 r.p.m., the delivery is 233 pints per hour.
At speeds in excess of 750 r.p.m. the inertia of the
fluid columns causes displacement of the castor oil.
Running without castor oil.—The pump was run for
Paris—London Aerial Post.
INTERVIEWED by the Petit Parisien, M. D'Aubigny,
Deputy President of the Inter-Ministerial Civil Aeronautic
Commission, has stated that the project for the establishment
of a postal aerial line between France and Great Britain,
which was approaching realization, would be very useful, as
it would put the members of the Inter-Allied Committee at
Versailles into rapid communication with the British Govern-
"I
"I
/o
/o
It
/o
1.90
1.85
0.77
O.50
1.68
1.46
0.122
0.130
••§8
Fig. 30.—Diagram of water-cooling system.
°l
0/
la
Jo
/o
0/
/o
0/
/o
c
/
/o
0.176 0.48
0.210 0.77
S.
28
0/
"I
.2 >H
0/
/o
o;
/o
Crank-case 0 . 1 8 0 . 8 9 0 . 9 3 Trace 6.20 9 . 5 9 Trace 82.21
b y diff.
Copper.
Antimony.
Tin.
Lead.
"I
/o
/o
°l
/o
0.90
Bearing metal
11.9S
/o
8.10
78.57camshaft were made on
The analyses of gear wheel and
drillings taken from the cores, as these were case-hardened
parts.
Mechanical tests gave results as under :—
Yield Ultimate Elonga- Reduction
Point. Stress, tion. of Area. Impact.
Tons per Tons per
sq. in. sq. in.
7o
Ft./lbs.
7.
Crankshaft . . 55.2
62.5
21.3
26 .
59-75
—
Cylinder
..
—
8.36 Nil
Nil
—
Connecting rod 41.9
48.1
14.0
—
Crank-case . .
—
8.91
ment. He also said that the idea was conceived before the
Rapallo agreement, and M. Flandin was entrusted with a
mission to the British Government to consult with the Air
Board. At the same time, the Minister of Commerce
empowered the Director of the Postal Services to negotiate
with the Fost Office for a postal convention. The agreement
in principle has been settled, and it is now a matter for the
British Government to arrange the definite agreement.
1334