Hall Aluminum XPTBH-2

Hall Aluminum XPTBH-2

Hall Aluminum XPTBH-2

During the Golden Age of flight, thousands of new aviation firms emerged, each one offering its idea of what themilitary or the public wanted. By far the greater percentage of these firms failed within their first few years, with only the remains of a prototype and worthless stock certificates to mark their passage.

The reasons for this vary. In some instances, the whole thing was a scam from the start, an attempt during the stock-boom days of the 1920s to raise money from a gullible public without regard to the merits of the design. In other cases, the competition was simply too strong for the design being offered, and the market prevailed.

Even relatively well-set up companies, such as Berliner-Joyce orGreat Lakessurvived only briefly. Thus it is even more amazing that the small Hall Aluminum Aircraft Company could endure for fifteen years before being folded in a friendly fashion into Consolidated Aircraft. During that fifteen year period, the company produced only 29 airplanes in a wide range of types that included an innovative personal plane, Navy fighters, a superb looking torpedo plane, and the largest American biplane flying boat since the Curtiss NC-4. This was the subject of this Aerial Oddity, the four- engine biplane flying boat, the Hall Aluminum XP2H-1, an elegant anachronism that combined advanced structural ideas in an antiquated configuration.

The firm’s survival depended upon the personality of its founder, Charles Ward Hall, and his relentless pursuit of ever more efficient aluminum structures. Long before weight reduction programs were a part of every new project, Hall was determined to reduce weight by every means possible. He came by his interest in aluminum naturally, for his father, Charles Martin Hall, had invented the process for the mass manufacture of aluminum. The elder’s Hall invention transformed aluminum from primarily being used for jewelry to its modern industry-wide applications, and he founded the firm that became ALCOA. Not a bad intellectual, financial or technical patrimony.

Charles Ward Hall founded his own company in 1927, after acquiring experience with two personal projects. The first of these was his small sailboat of 1922, where he rigged a wing from a surplus Thomas Morse to a novel pivoting mast. The second was the Hall Air Yacht, a rather grandly named two seat flying boat powered by a three cylinder 60 horsepower Wright Gale engine. The hull, lower wing, tail booms and tail unit were constructed of aluminum, which would become his pun-intended hallmark. The 25 foot span upper wing was conventional wood and fabric. The Air Yacht’s empty weight of 530 pounds took it out of the ultralight class, but it performed quite well—and was sufficient to convince Hall that aircraft manufacturers would in the future use aluminum as the preferred structural material.

Charles Ward Hall Incorporated began its long association with the United States Navy with a contract to build an aluminum version of the wooden wing used on the Curtiss HS-3 flying boat. The wooden version of the wing weighed 1,314 pounds, while Hall’s aluminum version weighed only 851 pounds. It was just as strong, and its success inspired the Navy to give him a contract for an aluminum version of the Navy’s the diminutive TS-1 fighter. The TS-1 had been designed by the Naval Aircraft Factory specifically for use on board the Navy’s first carrier, the U.S.S. Langley. Curtiss won a contract to build 34 TS-1s, all using the new Lawrance J-1 radial engine.

Hall redesigned the TS-1 as an all-aluminum aircraft. Two were built by Curtiss as the Curtiss Hall F4C-1. Slightly altered in the wing layout, the aluminum version weighed 300 pounds less than its wooden siblings.

The Navy and Hall were mutually impressed with each other, so much that Hall was awarded two new contracts. One was for the XPH-1, an all-aluminum version of the standard Navy Patrol boat. The configuration was both antiquated and ubiquitous as the Naval Aircraft Factory (NAF) PN-7 design had led to a long series of basically identical aircraft built by the NAF,Douglas, Hall, Keystone and Martin. There were two big differences in the Hall aircraft and all the others. The first was appearance—the Hall Aluminum PH-1 was considerably cleaner than any of the rest. The second was weight—the Hall version was much lighter. The heaviest of the lot, the NAF PN-9 had a maximum take-off weight of 18,069 pounds compared to the Hall XPH-1’s featherweight 13,228 pounds. The XPH-1 made its first flight on October 29, 1929, and flew 288 hours before being static tested to destruction at the NAF in 1932.

The Hall performed significantly better in the air, and on the water, and was rewarded with three contracts. The Navy bought nine as the PH-1 (Hall’s largest order ever), each costing a princely $53,778 each (plus Government Furnished Equipment.)  The last one was surveyed in February, 1941, with a total of 2,121 flight hours—an average of about 236 flight hours per year, not bad for the pre-war days.

Unlike any other peacetimeU.S.military aircraft, the basic design was called back into production on two more occasions. The Coast Guard loved the airplane for its rough-sea handling qualities—it could take off in five foot waves in 17.7 seconds. It bought seven in 1936 as the PH-2 then purchased an additional seven as PH-3s in 1939, ten years after the original Hall variation was laid down. The PH-3s flew well into World War II on anti-submarine patrol

The second contract was for the fighter was an altogether different proposition, an original aircraft that showed Hall’s penchant for structure rather than streamlining. Hall personally assessed each part, analyzing it statically and dynamically to insure that strength was adequate while weight was at a minimum.

The XFH-1 was of fairly conventional appearance, except for the unusual manner in which its upper wing was swept back 6 degrees, while the lower wings were swept forward six degrees. This provided a much improved forward visibility over most biplane fighters of the time.

The exterior was conventional, concealing the buoyant, water-tight fuselage, an innovation that proved itself later on a test flight. But it was the monocoque structure of the fuselage which was different. Hall had developed a variety of flanged, closed aluminum tubing shapes. He used these extensively, concentrating two, three or four of the tubes as the load requirements dictated. These tubes were used extensively throughout the XFH-1 and all of Hall’s later aircraft.

In the XFH-1’s wing spar structure, the multiple tubes were cambered in such a way that the air-loads straightened—and strengthened—the spar. The wing drooped slightly on the ground, but was absolutely straight at its maximum flight loading.

Much of the XFH-1 and other Hall products’ structure were conventional, of course, with bulkheads built up of drawn sections, riveted then reinforced with gussets and angles of steel.

The XFH-1 was tested at Anacostia from September 25 1929 through February 3, 1930. It was not as fast as contemporary Boeing or Curtiss navy fighters, obtaining a top speed of only 153 mph from its 450 horsepower Pratt & Whitney R-1340 engine. Yet it demonstrated the value of its water-tight hull on February 18, 1930, when an engine failure caused it to land on the water. The pilot didn’t have time to jettison the wheels (a feature Hall had thoughtfully included) and the impact caused some leaks. Even so, the fuselage was only about one-quarter full when it was recovered almost two hours later.

In what suspiciously looks like a bit of spending of the last of the annual budget, the Navy ordered the largest American flying boat since the Curtiss NC-4 on June 30, 1930. It was the Hall XP2H-1, a handsome biplane that was similar in appearance to the smaller but more familiar British Short Singapore III. Four 600 horsepower Curtiss V-1570-54 engines were mounted in tandem pairs in a handsome streamlined installation. At a maximum gross weight of 44,000 pounds, the XP2H-1 had a top speed of 139 mph, not bad for its size.

The XP2H-1 had all the Hall standard features of construction, including a hull that had been scaled up from that of the PH-1. Probably the largest single bay biplane ever built, the XP2H-1 had a span of 112 feet, and used the Clark Y airfoil that Hall favored. The trapezoidal wing had a long center section with a chord of 185 inches, with outer panels that tapered to 85 inches at the top.  The wings had the typical Hall internal structure, covered with sheet metal, and were braced with struts and wires.

One unusual characteristic of the Hall series were the ailerons, which were mounted via a continuous hinge on the top surface of the wings, sealing them off for a beneficial aerodynamic effect. An old friend of mine, Earl George, worked on the XP2H-1, and he said that attaching the ailerons was a time consuming, knuckle slicing job.

The normal crew of six saw the pilot and copilot seated side by side in the enclosed cockpit. An open bow position was available for a bombardier and for mooring operations. The navigation and radio equipment compartment was just behind the pilots, and behind this were Spartan “living quarters” for the long flights. The flight mechanic was situated further to the rear with a complex set controls to monitor the engines and the elaborate fuel tank system.

The first flight was almost a disaster. Famous test pilot Bill McAvoy was at the controls when the aircraft pitched up on take-off. He stop-cocked the controls, got the nose down and taxied back, to find that the elevator had been installed in reverse.

The XP2H-1 was delivered to the Navy on October 1, 1932, and proceeded to demonstrate a remarkable performance for a big biplane flying boat.  With a full load of 3,360 gallons of gasoline, the optimized range was an amazing 4,560miles. As weight was burned off, engines were shut down, and the final leg of an endurance flight was completed on two engines. The specification called for a 1,500 foot altitude capability with two engines out. The big biplane could actually climb on just the two front engines, and easily maintained the altitude on the two rear engines. With one engine out, it could maintain 7,000 feet, quite a performance for the time given that the propellers were fixed pitch. (The two forward propellers had a left hand rotation, while the two rear propellers rotated to the right.)

Sea handling qualities were excellent and the XP2H-1 was able to take off from six foot waves in 21.5 seconds. Unfortunately, the structure was not as strong as the Navy liked, which would have unfortunate results later.  An unusual first was an “auxiliary power unit”—a 1-1/2 horsepower gasoline engine used to raise the 250 pound anchor.

The XP2H-1’s day in the sun (literally) came in early 1932, when the XP2H-1 made a non-stop flight fromNorfolkVirginiatoPanamain 25 hours and 15 minutes. It was commanded by Lieutenant John S. (Jimmy) Thatch, who a decade later would make history in fighter aviation with his development of the Thatch weave.

Despite the record attempt, new monoplane flying boats were already demonstrating that the XP2H-1 was obsolete, and there were no follow-on orders. The aircraft was destroyed when it broke up after making an open-sea landing later in 1935. The handsome XP2H-1 was the very last in the long line ofU.S.military biplane flying boats.

Charles Ward Hall lost his life on August 21, 1936 in the crash of a light plane of his own design and manufacture, the unusual Monoped, so called because of its single main wheel landing gear.  He was thus unable to see the first flight of the most beautiful airplane his company would build, the very advanced Hall Aluminum XPTBH-2. Built to a Navy specification which called for patrol, torpedo and bombing capability, the XPTBH-2 was a streamlined twin-float monoplane that featured a single huge tubular aluminum spar that supported all flight and sea loads. Two cantilever floats, derived from the standard Hall flying boat hull configurations, permitted the free drop of a full size destroyer type torpedo.

McAvoy was again the test pilot on the successful first flight of the XPTBH-2. It went through some minor modifications and was much appreciated for its 182 mph top speed when tested at Anacostia by Navy pilots. Navy requirements had changed, however, and no additional XPTBH-2s were ordered. The aircraft was destroyed at the Naval Torpedo Station atNewport,Rhode Island, during the 1938 hurricane.

Time had at last run out for Hall-Aluminum, and the company gratefully accepted an offer from Consolidated for its assets and patents. Many Hall employees joined the new firm. While no Hall Aluminum aircraft survives today, the ideas and philosophy of Charles Ward Hall survive not only aircraft using aluminum structure, but also in the ideas that are used with the new composite materials in which maximum strength at minimum weight is still a goal.

16 responses to “Hall Aluminum XPTBH-2

  1. John J. McKenna

    Most interesting! Had never read anything about Hall; the start of our aluminum industry and a great boon to aviation…
    Thank you so much for this interesting history.
    JJ Aviation Electronics Technician US Navy retired
    VFP-62 1957-1961 F9F-8P, F8U-1P USS Intrepid two Carib, two Med cruises
    VP-10 1964-1969 SP-2E, P-3A Deltic, P-3B
    VX-5 1969-1973
    VP-19 1973-1978 P-3B, P-3C Update I
    PMTC Point Mugu 1978-1982 EC-121K, NP-3A, ES-2D, ES-2G

    • Thanks for this, too, John. A very interesting company, and its founder was an interesting man. He died in the crash of an airplane of his own design with many unusual, weight saving features such as single wheel, outrigger, control runs overhead to reduce weight, etc. I was in contact with his brother for a long time; he went (with his company) to become part of Consolidated.

    • Thanks for this, too, John. A very interesting company, and its founder was an interesting man. He died in the crash of an airplane of his own design with many unusual, weight saving features such as single wheel, outrigger, control runs overhead to reduce weight, etc. I was in contact with his brother for a long time; he went (with his company) to become part of Consolidated.

      Best wishes,

  2. Was the Hall PH-1 Flying Boat the first aircraft to have flush (countersunk) rivets?

    • John, that’s a great question, and it may well be right on the mark. I’ve never researched the subject, but I suspect it was, as Charles Ward Hall was well ahead of his time; Hughes used flush rivets on the H-1 racer, and there may have been other applications around that time, but none that I know of as early as the Hall product.

      Best wishes


  3. The Hall airplanes had flush rivets. At least starting with the XHP-1. He had patented the use of flush rivets. See
    My grandfather was general supervisor at Hall (Buffalo to Bristol)then went to San Diego then Fort Worth, TX with Consolidated and then to Bell in Buffalo. I have some of his own photos. The fuselage of the XHP-1 is very smooth in those pictures.

    • Thanks vry much David, I appreciate your commentary and salute your grandfather!

    • Yes the Hall aircraft were in advance of their time. I got to know Mr. Hall’s brother by correspondence (the gentleman who went to Consolidated in Buffalo, as your grandfather did.) I have a movie of the Hall aircraft in flight and the big four engine boat is impressive!

  4. See patent 1847559 page 2 starting at line 28.
    “…preferably, as in my prior patent, with the heads of the rivets countersunk in the outer surface of the skin in conical depressions both in the skin and flanges of the stringers…”

  5. I am Charles W. Ward great granddaughter. Charles W. Hall’s father is John Hudson Hall not Charles Martin Hall . Charles Martin started ALCOA and ironically my grandfather, who married Julia Ann Hall (daughter of Charles W.) worked as a metallurgist there.
    The similar last name confused me at first as I started to study my family tree!!

  6. Interesting; I found this article while searching for the Hall Air Yacht.
    Unfortunately, a correction of your history is in order:
    Charles Martin Hall (founder of ALCOA) was born in 1863, making him about 13 years old at the time of Charles Ward Hall’s birth in 1877, and Charles Martin Hall never married or had any children.
    I would like to know more about he Air Yacht if you have any info on that.


    • Doug,
      Thanks for your comments. As the research was done several decades ago, and the material long since jettisoned in down-sizing, I cannot go back and agree with you or refute you. At the time I was in contact with Archibald Hall by telephone, and it is probable that I simply made a mistake, an incorrect inference or other error in regard to the founder of ALCOA. Archibald Hall is of course long dead, and I don’t have any contact with any of the other people involved at the time. I wish you well in your research!
      All best wishes

  7. Norman Friedman”s “U.S. Battleships”, p. 250 may have a clue to the mysterious career of the Hall XPTBH-2. Scheme F, one of the developmental concepts for the “North Carolina” class battleships, was a very radical design with guns aft and a hangar for “ten bombers” forward. The elevator hatch is very large, and assuming Friedman’s sketch is something like to scale, would fit the fuselage length of the XPTBH-2. The timing fits, and the early elimination of the hybrid Scheme F would explain the termination of the Hall torpedo bomber.

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