Pitcairn Mailwing earned its aura

Pitcairn Aircraft hit the sweet spot for its airmail and sport biplanes with the Mailwing series from 1927 to 1931.

Decades after the prime for these biplanes, A-list actor Steve McQueen, called the King of Cool in Hollywood, bought a beautifully restored Mailwing, adding to its cachet.

Harold F. Pitcairn, associated with Pittsburgh Plate Glass, had a lifelong interest in aviation. He enlisted the talents of Agnew Larsen as a designer and engineer for aircraft projects.

Several biplane designs showed promise, and then the PA-5 Mailwing was introduced in mid-1927, the beneficiary of the preceding designs.

The PA-5 Mailwing was infused with a purposeful goal as a mailplane. Harold Pitcairn obtained the contract to fly airmail between New York and Atlanta, and his Mailwing iterations did the job.

The PA-5 Mailwing had a single open cockpit, with a closed compartment ahead of the pilot for mail or cargo. With a 500-pound payload, the PA-5 was designed for work.

A radial Wright J-5 Whirlwind engine developed 220 horsepower to power the PA-5 Mailwing.

During PA-5 production, the landing gear evolved with the times, replacing a straight axle with the more shock absorbent split axle style. A tailskid served the PA-5 in an era when unpaved flying fields were common.

Probably a dozen PA-5s were delivered in 1927, many serving airmail route No. 19, which was awarded to Pitcairn in February 1928. Soon the Pitcairn operation was flying 16 of its own PA-5s.

The PA-5 mailplane lent its design to Pitcairn’s Sport Mailwing in 1928, a three-place sport plane in which the front passenger cockpit could be faired over with a hatch, boosting speed when flown as a single-seater.

The Pitcairn PA-5 Mailwing had an upper wing spanning 33 feet and a lower wing of 30 feet. Length was one inch shy of 22 feet, and height was 9 feet. Empty weight of 1,612 pounds allowed for a useful load of 1,008 pounds, of which the payload was 500 pounds.

The PA-5 could hit a top speed of 130 mph; in demonstrations and races, PA-5s were clocked as fast as 138 mph.

The PA-5 had a ceiling of 18,000 feet and a range of 600 miles.

The factory price of $10,000 was lowered to $9,850, according to historian Joseph Juptner, whose seminal “U.S. Civil Aircraft” series of books provide a detailed look at the American aircraft industry, especially of the 1920s and 1930s.

The PA-5 used a combination of round and square steel tubing, welded to make the fuselage frame. Wooden fairing strips provided suitable shaping for a fabric cover. The wings employed spruce spars and built-up wood ribs, covered in fabric.

Tail surfaces were fabric-covered welded tube structures. PA-5s were built at Pitcairn Aircraft’s facility in Bryn Athyn, Pennsylvania.

Experience gained with the PA-5 led the Pitcairn team to make some alterations in late 1928. Cargo hold capacity was enlarged to 40 cubic feet, with an increase in payload weight now reported as varying between 558 to 695 pounds.

The resulting PA-6 Super Mailwing, with other tweaks to the landing gear and center wing section, continued in revenue mail and cargo service.

It begat the Super Sport Mailwing version, a three-place open cockpit aircraft. Length increased to 23 feet, 4 inches, and height was now listed as 9 feet, 2 inches. With the extra weight capacity of the PA-6, its Wright J-5 engine produced a top speed of 128 mph, with cruise listed as 109 mph, and a ceiling of 16,000 feet.

Depending on how it was equipped, a PA-6 Super Mailwing sold new at the factory between $8,500 and $11,500, according to Juptner.

Pitcairn’s team embraced new ideas like the NACA-devised low-drag engine cowling on the proposed PA-6B variant, requiring recontouring of the fuselage to take advantage of the cowling that shrouded the Wright J-5 radial.

But the aircraft went on without the cowling, using a Wright J-6 engine of 225 horsepower as the Pitcairn PA-7M mailplane and PA-7S sport aircraft. Metal lining of the mail and cargo compartment was a fireproofing measure in the PA-7M.

The Pitcairn PA-7s were said to cruise at 115 mph with the J-6 powerplant, and had a service ceiling of 16,000 feet.

During production of the PA-7 series in 1930, the Pitcairn Aircraft Co. relocated from Bryn Athyn to Pitcairn Field at Willow Grove, Pennsylvania.

The Mailwing name had one more fling as the Pitcairn PA-8, significantly, if subtly, different from earlier Mailwings. Capability was boosted by the mounting of a 300-horsepower nine-cylinder Wright J-6 radial. Tail surfaces were given a rounded shape, and the already rakish windscreen was swept back even more, and fitted with shatter-resistant glass, no doubt attributable to the automotive glass developed by Pittsburgh Plate Glass, the company co-founded by Pitcairn’s father.

The PA-8 Super Mailwing had an upper wing span of 35 feet, a length of 24 feet, 10 inches, and a payload that could top 1,000 pounds. Top speed was now 145 mph, with cruise at 122. Ceiling was 16,000 feet, and cruise range was 600 miles, figuring on burning 15 gallons per hour. The Pitcairn PA-8 featured Bendix brakes for the mainwheels, and a rubber-mounted tailskid in a landing gear arrangement that looks very transitional today.

The PA-8 type certificate was issued in September 1930. Six PA-8 Super Mailwings are known to have been built, at least five outside the prototype serving Eastern Air Transport.

After the short run of PA-8s, the Pitcairn aviation interests centered mainly on development of autogiros instead of fixed-wing aircraft.

Eastern Air Transport — later Eastern Airlines — was a successor to Harold Pitcairn’s original airmail contract company. Pitcairn had another significant intersection with aviation developments when his Willow Grove airfield was bought by the U.S. government under eminent domain principles in World War II to become Naval Air Station Willow Grove.

Thanks to Gerald H. Balzer 1926-2024

In June 2024, the historical aviation community lost a hard-working, knowledgeable, and generous member with the passing of Gerald H. Balzer at age 97.

Gerry Balzer amassed a large and diverse photographic collection, in addition to writing books and articles on historic aviation topics.

When you see Gerald Balzer’s name associated with captions to photos in Of Wings & Things columns, give him a quick memorial thank you, as I do every time I use a picture he graciously shared from his collection.