mNFfDEN I IAL
File D 52..1 / Fokker/ 65
( AVIATION)
PUBLISHED BY THE CHIEF OF AIR SERVICE, WASHINGTON, D. C.
Vol. V April I , 1923 No.415
PERFORMANCE TEST OF FOKKER C0.-4
EQUIPPED' WITH LIBERTY "12" ENGINE
I
( PERFORMANCE TEST REPORT NO 97 )
Prepared by
Engineering Division, Air Service
McCook Field, Dayton, Ohio
October 2, 1922
WASHINGTON
GOVERNMENT PRINTING OFFICE
1923
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CERTIFICATE : By direction of the Secretary of War the matter contained herein
is published as administrative information and is required for the proper transaction
of the public business.
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PERFORMANCE
TEST OF FOKKER CO~ ~-E.~
LIBERTY "12" ENGINE.
OFFICIAL PERFORMANCE TEST- SUMMARY OF
RESULTS.
Airplane: Fokker C0-4.
Number: A. S. 68557.
Type: X.
Engine: Liberty 12.
Propeller, 37593.
OCTOBER 2, 1922.
Equipped as: Corps Observation.
Weight empty (including water) : 2,911 pounds.
Armament and equipment: Armament, 297; equip-ment,
314; total, 611 pounds.
Crew: 360 pounds.
Gasoline : 540 pounds.
Oil: 72 pounds.
Weight loaded : 4,494 pounds.
Weight per square foot : 10.8 (416. 7 square feet).
Weight per horsepower: 11.23.
Climb. Speed.
Standardi- --,-----,---- ,---,----- 1----,---,---,-----
a~i,'!i~ Time Rate Flow I Flow
0
6,500
10,000
15,000
116, 100
217,900
in min. R. p.m. lt./min. gal./hr. M. P· h. R. P· m. gal./hr.
8.2
14. 8
32.9
41. 5
1,530
1,515
1,500
1,470
1,460
1,445
1 Service ceiling.
990
630
440
160
100
0
130.9
127.5
122.6
108.5
102.6
89.o I
1,695 ········
1,645 ... · ····
1,605 ... .... . 1,520 1· ...... . 1,495 ... . ... .
1,445 ·•······
' Absolute ceiling.
Endurance, ; hour at ground, 3 hours at 10,000 feet.
Minimum speed at sea level (lowest throttle): 67 m. p. h.
Landing speed:---.
DISTRIBUTION OF WEIGHTS.
(By pounds.)
PILOT'S OBSERVATION.
TAXYING.
The C0-4 does not taxi very easily, no doubt due to the
small rudder and large fuselage. It is especially difficult
to taxi in a cross wind. In view of the fact that it has no
steerable tail skid, it is neceBBary to lift the plane into
positlon on all small fields.
TAKE-OFF.
The plane takes off normally with good climb ; however,
at higli altitudes, it requires a very long run before actually
taking off. The actual run is believed to be slightly
greater than that required by a DH-4-B at the same alti-tude.
·
LANDING.
The plane lands very slowly, with no tendency to drop
out; on the contrary, the plane has the ability to "hang
on 1•· to the very last.
STABILITY.
Airplane is stable longitudinally and laterally, and due
to the lack of dihedral does not have a tendency to return
to normal position; as a consequence, it must be "flown"
at all times. In normal flight, the airplane is slightly tail
heavy.
MANEUVERABILITY.
This airplane has excellent maneuverability, the effort
actually required to operate the controls being very
slight, with a corresponding quick response on all controls.
It does an excellent climbing turn and will retain
controllability even when placed in extreme positions of
climb.
VISIBILI'rY.
Weight-empty (with water): 2,911.
Armament and equipment: Armament,
ment, 314; total, 611.
Visibility is very good, except forward and downward.
297; equip- Due to the large gap between the wings, the pilot is given
unusually good vision for an airplane of this type.
Crew: 360. ·
Gasoline : 540.
Oil: 72.
Weight loaded: 4,494.
Weight on front wheels (tail skid on ground):-- -.
Weight on tail skid (tail skid on ground):--.
1 Weight on front wheels (flying position): 4,062.5.
Weight on tail skid (flying position) : 253.5.
Center of gravity (distance from wheels in flying position):
15.59 inches.
Provisions for special equipment not carried during test.
1 178 pounds ballast added after weight was obtained to increase gross
weight to 4,494 pounds, as per memorandum of June 19, 1922, T. E .
Tillinghast, project engineer.
MAINTENANCE.
Due to the simple construction of the fuselage, which
is made of tubular steel, and the general acceBBibility of
the motor and controls, the C0-4 is an excellent airplane
from the point of view of maintenance, in these respects;
however, it is questionable if the type of wing now in
use will be succeBBful from a maintenance point of view,
on account of the fact that the wings received approximately
only 100 hours flym'g time and when uncovered
were found to be in very bad condition; nails and rivets
had loosened; the wood had shrunk; the fittings had pulled
away from the spars; and the wires were found to be very
slack, as well as other minor troubles.
37112-23 (1)
SUMMARY.
It is believed that the C0--4 will, 111 time, make an
excellent airplane for corps observation work. It will,
however, be necessary to carry out several changes and
experimentation, especially regarding the wing structure.
While on a short practice flight around an airdrome, the
airplane is apparently very easy to handle, clue to the
responsiveness of the controls, it is found that on long
cross-country trips, due to the lack of dihedral and lack
of adjustable stabilizer, flying this airplane becomes very
trying on the pilot, especially in rough air, since the plane
must be "flown~' at all times.
DESCRIPTION OF POWER PLANT.
Make: Liberty 12- A.
Factory No.: 78.
A. S. No. : 23509.
ENGINE.
Type: 12 water-cooled.
Number in plane: 1.
Location: Nose.
Rated h. p.: 400.
Rated r.p.m.: 1,700.
Bore: 5 inches.
Stroke: 7 inches.
Compression ratio: 5.43 : 1.
Weight, dry: 845.
Gas consumption: 216 pounds per hour.
Oil consumption: 16 pounds per hour.
Weight of water in engine: 45 pounds.
IGNITION.
Battery or mag.: Battery.
Make: Delco.
Number: 2.
Advance, degrees: 30°.
Distributor: Delco.
Plugs, make: B. G.
Gap: 0.015.
Make: Zen).th.
Type: U.S. 52.
Number: 2.
CARBURETORS.
Gas drains: Tube direct from carburetor.
Air intake: Vertical ·overhead scoops.
Mixture control: Back suction type.
Effective to altitude: Yes.
RADIATORS.
Make: Unknown.
Type: Round tube , hex. ends ..
Number: 2 (1 Lamblin).
Position: Nose and under fuselage.
Frontal area: 4.8 square feet.
Depth: Honeycomb, 4:f inches.
Length: 39.5 inches; "L," 26.378 inches.
Width: 27j inches; "L,'.' 13! inches.
Radiator surface: 230 square feet; "L," 88 square feet.
Temp. ajt.: Shutters.
Water cap., lbs.: Unknown.
Flow, gal. per min.: Unknown.
Water capacity of whole system: Unknown.
2
EXHAUST PIPES.
·Description: Standard manifold.
.LUBRICATION.
Capacity oil tank: 72 pounds.
Oil used (brand): Liberty.
Oil pressure: 42 square inches.
Oil temp. : Inlet, 122° F .; outlet, 139° F.
Type pump: Gear.
Wet or dry sump: Dry.
Description lubrication system: ls of the dry sump
force-feed type with oil supplied under pressure to main
bearings, connecting rods, and cam shafts, and by spray
thrown up on pistons, wrist pins, and cylinders.
FUEL SYSTEM.
Number of tanks: 1.
Location: Under carriage.
Total capacity, main pounds: 540:
Description of fuel-supply system: Air pressure pump,
hand operated to start, then change to motor pump.
ENGINE CONTROL.
Description: Rod and lever.
PROPELLER.
Make: McCook.
Number blades: 2.
Diameter: 9 feet 10 inches.
Pitch: 6.91.
Tips: Terneplate.
Mig. No.: 37593.
A. S. No.: 109398.
DESCRIPTION OF AIRPLANE.
DIMENSIONS.
Overall span: 39 feet 4 inches.
Overall length: 29 feet 2! inches.
Overall height: 10 feet 10 inches.
Height at hub of propeller above ground: In flying
position, 5 feet 6 inches. ·
AIRPLANES.
Sweep back: None.
Dihedral, degrees: None.
Stagger: 40 inches.
Total area including ailerons: 416.7.
Gap: 70.7 inches.
UPPER PLANE .
(Including center section.)
Span: 39 feet 4 inches.
Chord: 80 inches.
Area, with ailerons: 272.7.
Incidence, degrees: 2° leading edge to trailing edge.
LOWER PLANE.
Span: 35 feet 5 inches.
Chord : 56 inches.
Area: 144. •
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AILERONS OR FLAPS.
Number: Two.
Arrangement: Hinged to upper rear spar at wing tips.
Upper length: 112.5 inches.
Upper chord: 11 to 12 inches.
Upper area: 18. 7 square feet.
CENTER SECTION.
Area: None.
Contents: Gas tank.
STABILIZER.
Area: 17.3 square feet.
Setting: +3° 30'.
Chord: 38 inches maximum.
ELEVATOR.
Area: 23 square feet.
Balanced area: 1.39 square feet.
Distance from leading edge of elevator to center of
gravity of airplane: 20 feet ! inch.
Chord: 23} inches.
3
RUDDER.
Area: 10.1 square feet.
Balanced area: 1.04 square feet.
Distance from leading edge of rudder to center of
~ravity of airplane: 20 feet 1 inch.
FUSELAGE.
O;r
Max. cross section shape: 3•s·
Max. cross section area: ,,.,..,r ,
Max. cross section dimension: 42 by 48 inches.
LANDING GEAR.
Number of wheels: 2.
Tread: 6 feet 5! inches.
Shock absorbing system: Elastic cords.
Braking device: Tail skid.
Wheels ahead of center of gravity: 15.15.
FIN.
Area: None.
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