In 1925 the U.S. Postal Service felt they had excellent operational service with converted Airco D.H.4 biplanes. The eight-year-old designs were considered antiquated by this time, however, and a modern purpose-built machine was desired. While most manufacturers started to build new generation passenger aircraft with mail cargo capability, the Curtiss Carrier Pigeon was the first clean-sheet design specifically made for U.S. air-mail service. The aircraft was intended to be sold directly to the Postal Service, but new legislation that opened up outside contracts brought on a slew of competing models.

The Carrier Pigeon was drawn up to meet or exceed the original postal specifications. Strength, serviceability, and ease of maintenance were the three core design criteria. It was intended to provide service on the night-time runs between Chicago and New York, with only one stop. The plane was built to take advantage of the powerful and plentiful 400 hp Liberty L-12 engine to meet Postal specifications. Up to 40,000 airmail letters could be carried in the 1,000 lb capacity cargo hold.

The fuselage was a welded steel tube frame covered in fabric. The upper and lower wings were interchangeable and used solid, unspliced spruce spars. The rudder, ailerons, and elevators were also interchangeable, which reduced spares counts. The hinges used heavy replaceable bronze pins to reduce wear.

The watertight cargo hold was at the center of gravity so the aircraft could accommodate a range of loads without affecting the balance. The landing gear used rubber doughnut suspension. The fuel tank could be jettisoned in case of an emergency. A seven quart fire extinguisher was plumbed to the engine compartment for suppression of inflight fires. The pilot could choose between wheel or stick control based on his preference.

A prototype Curtiss Carrier Pigeon flown by Charles S. (Casey) Jones placed 7th in the 1925 Edsel B. Ford Reliability Tour. Out of 17 starters, 11 aircraft including the Carrier Pigeon completed with a perfect score, netting a $350 prize. Henry Ford waited at the finish line to greet the winners of the 1,900 mile endurance test.

The Carrier Pigeon was used by National Air Transport Inc. At the time, both Curtiss and NAT were owned and controlled by Clement Keys. Ten Carrier Pigeons were put into service with 35 surplus Liberty engine spares. NAT used the Carrier Pigeon for the Contract Air Mail CAM-3 (Chicago-Dallas) route. The first recorded service was on May 12, 1926 with the route between Chicago, Illinois and Dallas, Texas. Stops were scheduled in Moline, Illinois, Saint Joseph, Missouri, Kansas City, Missouri, Wichita, Kansas, Oklahoma City, Oklahoma and Fort Worth, Texas. The maiden flight was piloted by D A Askew, R L Dobie, R H Fatt, Lawrence H Garrison, P E Johnson, H L Kindred and Edmund Matucha. These pilots logged 776,351 miles of flight in the first year without an accident or loss of any mail.

NAT invested $10 million competing for the night-time Chicago to New York route (CAM 17). NAT started service on September 1, 1927 using Carrier Pigeons from CAM-3. These planes flew the early lighted airway from Chyenne to Chicago, and recently extended to New York. The path over the Allighenies was referred to as the “Hell Stretch”. Early in 1929, NAT acquired seven 625 hp Curtiss Falcons, these replaced the smaller Carrier Pigeons. D. A. Askew flew the final Carrier Pigeon flight. He had flown this same aircraft on the inaugural CAM No. 3 flight. On February 9, 1934, the Post Office cancelled all airmail contracts on suspicion that the mail carrying contracts had been awarded through collusion during the previous administration.

One fatal airmail crash was recorded in a Carrier Pigeon. Arthur R. Smith was killed in aircraft #602 when he hit trees near Montpelier, Ohio, en route to Chicago.

On November 27, 1929, Evelyn “Bobbi” Trout and Elinor Smith took off from Metropolitan Airport in a Commercial Sunbeam biplane in an attempt to set an official record for a refuelled endurance flight by women. A Carrier Pigeon was used as the tanker aircraft, which refuelled the Sunbeam 3 1/2 times. The Sunbeam was to be refuelled in early morning and before sunset. Refuelling went well. With shifts of four hours each, two days passed. By Thanksgiving Day, they had been up for 39 hours. While refuelling, the Carrier Pigeon began trailing black smoke. Trout quickly tossed the fuelling hose over the side as Smith maneuvered away from the ailing Carrier Pigeon. It landed, and the fliers emerged safely.

The Carrier Pigeon 2 was built by the Carrier Pigeon Co of Buffalo, New York in 1929. This was a larger and modernized version of its predecessor with a 600 hp geared Curtiss Conqueror and a three-blade prop.

The Curtiss Lark model 41 was the follow-on aircraft, employing four interchangeable wing panels.

Curtiss Model 40 Carrier Pigeon I
Engine: 1 × Liberty L-12, 400 hp (300 kW)
Wingspan: 41 ft 11 in (12.78 m)
Wing area: 505 sq ft (46.9 m2)
Airfoil: U.S.A.27
Length: 28 ft 9.5 in (8.776 m)
Height: 12 ft 1 in (3.68 m)
Empty weight: 3,603 lb (1,634 kg)
Gross weight: 4,900 lb (2,223 kg)
Max takeoff weight: 5,620 lb (2,549 kg)
Capacity: 1,000 lb (450 kg) cargo
Maximum speed: 109 kn; 201 km/h (125 mph)
Cruise speed: 91 kn; 169 km/h (105 mph)
Stall speed: 43 kn; 80 km/h (50 mph)
Range: 456 nmi; 845 km (525 mi)
Service ceiling: 16,700 ft (5,100 m)
Rate of climb: 800 ft/min (4.1 m/s)
Crew: one

The first Curtiss fighter built under the US Navy designating system combining type, sequence of design and manufacturer, the F4C-1 was designed by Charles W Hall. It was essentially an all-metal version of the wooden Naval Aircraft Factory TS-1, which had been designed by the US Navy Bureau of Aeronautics and production had been assigned to Curtiss.

The F4C-1, two examples of which were built in 1924 and the first flown on 4 September, embodied some aerodynamic redesign. Its wings featured tubular spars and stamped dural ribs, and the fuselage was built up of dural tubing in a Warren truss form, all being fabric covered. By comparison with the TS-1, the lower wing was raised to the base of the fuselage. Armament comprised two 7.62mm machine guns and power was provided by a nine-cylinder Wright J-3 radial rated at 200hp.

Take-off weight: 774 kg / 1706 lb
Empty weight: 466 kg / 1027 lb
Wingspan: 7.62 m / 25 ft 0 in
Length: 5.59 m / 18 ft 4 in
Height: 2.67 m / 8 ft 9 in
Wing area: 17.19 sq.m / 185.03 sq ft
Max. speed: 203 km/h / 126 mph
Range: 845 km / 525 miles

Also entered in the 1922 Pulitzer Race was a pair of Army Curtiss racers originally called CR-2 but later changed to R-6 (Model 2A). Curtiss built them two R-6 developed from the US Navy’s CR. The R-6s were considerably cleaner and a major contribution to drag reduction was the introduction of wing surface radiators.

Lt. Russell Maughan won the race in No. P-279 (68564) at 206 mph, and Lt. Maitland was second (68563) at 199 mph in No. P-278. Both airplanes then flew in the 1923 Pulitzer, Lt. Corkill placing sixth in P-278 at 216 mph, and Lt. Miller fifth in P-279 at 219 mph. In the 1924 Pulitzer, P-278 disintegrated at the start, killing Capt. Burt Skeel, while Lt. Brookley went on to place second at 215 mph in the 1922 winner. The R-6s held the speed record several times: Billy Mitchell flew P-279 (68564) at 224.28 mph in 1922; Russell Maughan flew it 237 mph in 1923, and then Maitiand flew P-279 240 mph a short time later. The Curtiss racers were making a lot of history.

Engine: Curtiss D-12
Wingspan: 19’10”
Length: 18’11”
Useful load: 505 lb
Seats: 1

Three 1923 R2C-1 were built (A6691/6692, and A7054). The second became R2C-2, and the first was sold to the Army to become R-8. Is also seen as paper designation F2C.

In the 1923 Pulitzer Curtiss had two new R2C-1s. A pair of larger, but more streamlined, Navy racers. AI Williams won the race in No. A-6692 at 244 mph, closely followed by Harold Brow in No. A-6691 at 242 mph. Brow later took the world speed record away from Maitiand’s R-6 with a run at 259 mph, only to be topped immediately by AI Williams with 267 mph.

F2C and F3C were “paper” designations assigned to the R2C and R3C racing aircraft respectively.

R-8 / R2C-1 A6691 was purchased from the USN for $1.00 and rebuilt by the Army as 23-1235. It crashed before the 1924 race.

The sole R2C-2 from 1924, A6692, was the winner of 1924 Pulitzer Trophy for seaplanes and 227.5 mph. The R2C-2, on 22’7″ twin floats, was developed into the R3C-1.

R2C-1
Engine: Curtiss D-12, 507 hp
Length: 19 ft 9 in
Wingspan: 22 ft 0 in
Empty weight: 1,692 lb
Gross weight: 2,112 lb
Maximum speed: 267 mph
Range: 173 miles
Service ceiling: 31,800 ft
Rate of climb: 2,380 ft/min
Crew: One pilot

Curtiss produced a sucsessful post-World War I three seat two-bay biplane called the Oriole for the civilian market, with a moulded plywood fuselage and 90 hp Curtiss OX-5 V-8 engine.

Performance was improved when fitted with a Curtiss K-6 or C-6 (150-160 hp).

By 1921 surplus WW-1 machines like the Jenny were flooding the market, and Oriole production was tailed off.

With the closure of the Curtiss Oriole line, a number of complete fuselages became available and Ireland was able to secure these. With help from friends in the Curtiss design office, new wings were created for the Ireland Comet.

Engine: OX-5