THE GALLAUDET D-1 AND THE GALLAUDET DRIVE AIRCRAFT
By ROBERT A. GORDON
HEAD, GALLAUDET RESEARCH PROJECT
CONNECTICUT AERONAUTICAL HISTORICAL ASSOCIATION, INC.
The hollow hub was mounted on a spool or ring which ran on ball bearing races surrounding a fixed steel drum, which was the main structural member supporting the aft fuselage and tail. It was claimed that the Gallaudet Drive increased the propeller efficiecy nearly 10 per cent by enclosing the low thrust, high drag producing part of each blade within the fuselage ring. A further advantage of the mid-fuselage propeller location was that the centers of thrust and resistance became coincident.
The D-1 was powered by two Duesbenberg engines mounted side-by-side in the fuselage forward of the propeller. Either or both of the engines could drive the propeller through flexible couplings and spur reduction gears which meshed with a large internal gear attached to the forward face of the propeller ring. Another advantage gained from the engine-propeller configuration of the Gallaudet Drive design was the extremely good visibility offered the crew by their position in the nose of the airplane.
This system of propulsion was devised by an inventive genius who had been experimenting in the field of aeronautics since 1897. Edson Fessenden Gallaudet. Gallaudet, whiile a physics instructor at Yale, had built and flown a large warping wing glider model, several years before the Wright brothers perfected this method of airplane control.
However, Gallaudet's early aeronautical investigations were prematurely halted by pressure from his Yale superiors, who felt that a staff member who dabbled in this questionable field cast aspersions upon the Yale Faculty.
Edson Gallaudet did not return to aviation until 1910. He had formed the Gallaudet Engineering Company, a mechanical engineering and consulting firm, in January 1908 in Norwich, Connecticut, and with his brother Denison and Grosvenor Ely incorporated the firm in July 1910. Design and construction of the Gallaudet Aeroplane No. 1 was a large (44' wing span, 56' length), single float monoplane with a single 125 H.P. Emerson Aerial Engine mounted midships driving two propellers, one at the nose and one at the tail, much in themanner of the World War II German Dornier CO 335. Aeroplan No. 1 was tested in the summer of 1911, after Edson Gallaudet had obtained a pilot's license from the Wright school. Various problems however, including engine troubles, prevented Gallaudet's first design from flying higher than a few inches off the water.
Gallaudet's second design was the A-1 Bullet monoplane of 1912. The Bullet was powered by a 100 H.P. Gnome rotary engine mounted in the nose of the aircraft driving a pusher porpeller located behind the tail. This airplane was flown several times during May, June and July 1912 at Hempstead Plains, New York, and then on July 24 it crashed while doing an estimated 130 MPH, seriously injuring Edson Gallaudet. The accident ended Gallaudet's flying career but not his enthusiasm or his aircraft designing ability.
Gallaudet's next aircraft, the Model B monoplane flying boat, continued the arrangement of an engine enclosed in the fuselage driving remote propellers, in this case a pusher porpeller behind that trailing edge of each wing panel. The Model B was flown several times during 1913 and 1914 with several different engines, but does not appear to have been particularly successful.
The Gallaudet firm tempoorarly abandoned its search for a more efficient propeller arrangement with the construction of the Models C-1 and C-2 in 1914 and 1915. These two airplanes were conventional, two-place tractor biplanes, powered by Gnome rotary engines and were identical except for engine horsepower and wing span. The two Mocel C airplanes were very stable and were used as trainers at the Gallaudet Aviation School at Garden City, Long Island, throughout most of 1915 and by the New York National Guard, during the fall and winter of 1915-16.l
The Gallaudet Drive concept probably originated in 1914 as a continuation of Edson Gallaudet's search for a better engine-propeller arrangement. The earliest surviving general arrangement drawings showing the Gallaudet Drive configuration are titled "180 H.P. Hydroaeroplane for U. S. Navy" and are dated February 1915. It can be seen from the title of this drawing that the Gallaudet Company had hopes of selling this design to the Navy from the very outset.
The Gallaudet Drive design was entered in a Navy design competition in early 1915, but when the bids were opened on April 29, Gallaudet was found to be the highest bidder in a field of 14 entries at $18,000. The Navy was interested, however, in promoting the advance of aviation by encouraging new designs and decided that the D-1 held enough promise to merit a contract, even though it had not won the design competition. After negotiating the price down to $15,000, a purchase requisition for the airplane was issued on June 8, followed by New York Pay Office Supply and Accounts Contract No. 141 on September 2, 1915. U.S. Navy serial number A-59 was allotted to the D-1, usually referred to as the "59A."
The Gallaudet Company completed the D-1 design work during the summer of 1915 and construction was underway by fall. The wing span, area and engine horsepower were increased during this period over that orginally outlined to the Navy in the proposal letter. Except for the engine-propeller arrangement and the changes they made to the nose, the layout of the D-1 was quite similar to that already proven in the C-1 and C-2.
Gallaudet selected two 4-cylinder, water-cooled, 150 H.P. Duesenberg Aero Engines to power the D-1. These engines were finished by the end of December 1915, but were about two months behind schedule due to difficulties in getting finished material such as crank shafts, cam shafts, etc. The illness of Fred S. Duesenberg early in 1916 seemed to prevent his firm from testing and making final adjustments ot the engines and so Edson Gallaudet finally took it upon himself to go to the Duesenberg plant in St. Paul on February 11, 1916 to supervise this final work. By the end of the month the first engine had been tested and shipped to the Gallaudet plant and the second followed within two weeks. Also by February 29, the D-1 airframe was practically completed except for intallation of the engines.
Because of the construction delays on the engines, Gallaudet had to ask the Navy for a two month extension of the delivery date to July 2, 1916, the first of many such request he woude be forced to make as testing progressed.
Preliminary taxi trials were performed on the Thames River below Norwich in June, and it was found necessary to add additional radiators to those already built into the fuselage on either side of the engines. The original pilot engaged for these trials, Aviator Gordon, had been killed in a Curtiss tractor airplane a few weeks before. The only pilot Gallaudet could then hire was inexperienced in seaplanes and was unable to get the D-1 off the water, although the Gallaudet Drive mechanisim was proven to work satisfactorily.
The first flight of the D-1 wa made on July 17, 1916 with David McCullach, instructor at the Wanamaker Aerial Patrol School, as pilot. On the last of the several short, straight flights made that day a small hole was punched in the bottom of the main pontooon and the increased pressure withing the float blew off a section of the upper decking. McCullach was unavalable for further flights after the pontoon was repaired and a pilot named Sullivan was engaged. On August 3, with Sullivan piloting and Gallaudet employee Elsworth Williams flying as passenger in the front seat, the D-1 was damaged in a bad landing in which the forward float struts broke on impact with the water, dropping the forward fuselage onto the main float. The top of the main pontoon and the bottom of the fuselage nose were crushed in several places and a rib was damaged in the lower wing center section. It was claimed that only the quick actions of Williams in cutting the engines prevented greater damage.
The addition of the extra radiators, delays in obtaining test pilots and the accidents had slipped the delivery date to September 3, 1916. The D-1 was again repaired and ready for flight by August 21, but again Gallaudet's first choice as pilot, David McCullach, could not get away from his regular work and, as no other pilot could be found, flight trials had to be postponed. The Gallaudet Company employed no regular pilot since the Long Island flying school was shut down in the fall of 1915 and this lack resulted in much difficulty in maintaining test schedules.
Gallaudet's pilot problem was solved for a time with the employment of experienced aviatior Filip A. Bjorklund in the fall of 1916. Bjorklund had been flying in England, Sweden and the United States since late 1913 and had been an instructor on the Gallaudet C-1 and C-2, both for the Gallaudet flying school and the New York National Guard school in 1915. Bjorklund made many flights in the D-1 in October and November, 1916 and considered it a stable, pleasant flying airplane, although he did discover a porpoising effect which lengthened the take-off run.
On October 16 and 18 demonstration flights were made over the Thames River for Capt. Mark L. Bristol, the director of aviation in the Navy, and officers from the U.S.S. North Carolina, anchored off New London, Connecticut. On the flight on the 18th Bjorklund flew the D-1 down the Thames River, over New London and out over Long Island Sound. As he returned up the riger, engine trouble forced him to land on the water. The D-1 was towed back to its beth where examination revealed that a small break had occurred in the head of No. 1 piston on the port engine.
Duesenberg mechanics journeyed to the Gallaudet Plant in Norwich in late October, to install pistons of new design and give the engines a general overhaul. Even after the overhaul the engines continued to give problems; the next trouble found was poor water circulation causing engine overheating and pre-ignition. More work on the engines and stand testing followed before the re-installation in the D-1 was completed on November 21. By this time the delivery date had been postponed to November 30.
Flights were cut short on the 22nd by the engines back-firing constantly. This problem was cleared up by cleaning the magneto breaker and everything appeared set for flights on the 23rd of November. As a passenger, Bjorklund carried Ralph S. Barnaby, an Electric Boat Company representative, whom Gallaudet was attempting to interest in financially assisting his firm. At a height of some 30 to 50 feet above the water, after a long take-off run, the pilot's rudder bar suddenly broke, causing Bjorklund's foot to push forward, hitting Barnaby in the elbow. Fortunately, Barnaby immediately realized what had happened and centered the rudder with the forward rudder bar while Bjorklund made a straight ahead landing, using aileron and elevator control only. The D-1 was again towed back to its starting point and no further flying was attempted after repair of the rudder bar, due to worsening rain, fog and high winds.
The D-1 project had cost the Gallaudet Company nearly $40,000 this point, on a $15,000 contract of which $5,000 was for the engines. Due largely to this loss, the firm was re-organized and re-financed as the Gallaudet Aircraft Corporation, with the stock control passing to Frederick F. Brewster and W. A. Harriman, although Edson Gallaudet continued as President and Chief Engineer.
The Norwich plant building was quite small and the firm, with thoughts of expansion and production orders, secured land for the erection of a larger new factory in East Greenwich, Rhode Island. On November 27 Gallaudet requested that, since the poor weather and moving the plant to Rhode Island made further testing at Norwich impossible, the airplane be moved to the Naval Aeronautic Station. Pensacola, Florida, the flight tests and acceptance trials completed there and the delivery date postponed accordingly. On December 6 the Navy approved the request with the provision that, since the contract stated that flight tests were the contractor's responsibility, Gallaudet must supply the pilot and bear the costs of testing at Pensacola.
By mid-January 1917 the D-1 had been received and assembled at Pensacola and was ready for final flight trials. Again Gallaudet's difficulty in obtaining pilots presented itself. Bjorklund was not available and the pilot hired, Philip Rader, had not flown the D-1 before undertaking the official flight tests.
The Navy acceptance trials were performed on January 24, 1917. The Navy Board of Inspection for the tests consisted of Naval Constructor H. C. Richardson and Lt:'s (j.g.) Marc A. Mitscher and C. B. Strickland. Rader, unfamiliar with the D-1 and feeling his way as he went, refused to perform several of the tests at the full output of the D-1, including the low speed climb and turning runs. Also the Gallaudet Company would not allow the full load, high speed, four hour endurance run because it was felt the airplane was overweight and that this condition would possibly overload the engines on a full speed run of any length. The Board did not object to this since, at the 4600 lbs. weight at which most of the tests were made, there appeared to be a marginal reserve of buoyancy, and loadng the plane to the full load weight of 5117 lbs. required by the contract specification might have exceeded the safe limit. On the high speed tests the recorded average speed of 90.97 mph for three runs over a five mile course surpassed the contract requirement of 88 mph and the D-1 was still not pushed to full capacity. The landing and takeoff speeds used in the tests were estimated as approxmately 65 mph. A climb rate of 500 feet per minute was required, but Rader obtained a climb rate of only 180 feet per minute at 4456 lbs. weight. The Board considered this as not being representative fo the true climb performance. The contract also required the capability of riding adrift in the open sea in a 30 mph wind, but because of the scant freeboard and reserve buoyancy the D-1 was considered fit only for operations from a protected harbor in no more than moderate sea and wind.
The tests showed that the D-1 was quite airworthy, handled well, had good balance, flew steadily and responded actively to the controls. The Navy disliked the aileron system, however. The airlerons were of rather small area and acted negatively and only one pair at a time through a complicated system of bell cranks and plungers which, despite their complexities appeared mechanically satisfactory. Because of this type of aileron control the Board did not object to the pilot not pushing the airplane to the specification requirements during certain phases of the test.
The Navy did consider the aircraft in general to be thoroughly and substantially designed and built and to have a good stramlined form. No t4rouble was encountered with the engines, clutches, gears or propeller at any time during the test, although the engine installation was found to be cramped, giving poor accessibility. Also, the novel connection of the aft fuselage to the forward fuselage through the steel drum proved sturdy and gave no difficulty.
The Board of Inspection recommended that no duplicate D-1's be ordered, although they did not preclude further consideration of other designs of the Gallaudet Drive type.
Acting on the Board's recommendations the Bureau of Construction and Repair advised the Chief of Naval Operations that the failure to meet certain portions of the contract requirements be waived in view of the experimental nature of the airplane. "So far as this Bureau is concerned, it has determined that practicability of mounting the propeller as proposed and the object of purchasing this experimental seaplane has, therefore, been realized. It is recommended that the seaplane be accepted and paid for at once." The Gallaudet D-1 was thus accepted by the Navy on February 24, 1917, and given the designation AH-61 (Aeroplane Hydro-Number 61).
Because of the high wing loading, inadequate lateral control and low reserve buoyancy discovered during the acceptance trials, the Navy awarded Gallaudet a contract to modify the D-1 to correct these deficiencies. The plane was shipped to the new Gallaudet plant in Rhode Island during the summer of 1917 and the modifications were completed by December 18. The upper wing was extended approxjmately 17 feet and provided with double-acting ailerons of larger area. The ailerons were removed from the lower wing surfaces. New radiators were instralled which gave the same cooling capacity but saved 150 lbs. weight. The depth of the main pontoon aft of the step was increased, giving 300 lbs. additional displacement, both to increase the bouyancy and help correct the porpoising effect. New Duesenberg engines were also installed, probably of a lighter weight and higher horsepower than the original engines.
After completion of the modifications, testing was delayed because the water surrounding the Gallaudet plant was frozen. Then, before tests could be made, the Bureau of Steam Engineering directed Gallaudet to ship one of the D-1 engines to New York City, where it was used for instructional purposes. The D-1 spent the remainder of World War i, minus an engine, in storage at the Gallaudet plant, probably in an unassembled, crated condition. In February 1919 the Inspector of Naval Aircraft at Gallaudet requested disposition instructions on the D-1 from his superiors. The final end of the Gallaudet D-1 is not known, but being an obsolete, one-of-a-kind experimental airplane, it was probably scrapped shortly after.
Photo courtesy National Archives
First Gallaudet D-2 over Narrangansett Bay, Rhode Island, winter 1917-18. D-2s were enlarged version of D-1. Ordered by the Army Air Service for coastal defense. Power: 2 Hall-Scott A-5a.'s, 150 H.P. each.
|Meanwhile the Gallaudet Drive line was continuing. The new Gallaudet factory was occupied in late May 1917 before it was completed, and the airplane production was begun immediately with a U.S. Army Air Service order for four Gallaudet Drive D-2s. The D-2s were seaplanes similar in layout to the D-1 except for a larger 69 foot wing span. Powered by two 150 h.p. Hall-Scott A-5a engines, a three-man crew was carried, with the forward gunner in the nose in front of the pilot and the aft gunner located directly behind the fuselage-mounted propeller. The first D-2 was flown at East Greenwich in November 1917, the second at Langley Field, Virginia in February 1918, and the last of the type was delivered to the Army in June 1918.|
Felix Rossoll Collection
The Gallaudet D-3, a D-2 converted by installation of a Liberty engine, East Greenwich Bay, Rhode Island. It featured a third cockpit aft of the propeller, a modified nose section and a different rudder and fin. (GALLAUDET pilot Jack McGee was killed in a crash of this airplane on the morning of June 13, 1918).
|It is believed that one of the last three D-2s was finished to take the 400 H.P. Liberty engine and designated the D-3 (the original D-3 was a proposed large, enclosed cabin seaplane and was not built). Gallaudet pilot Jack McGee was killed in this aircraft while performing flight trials in June 1918 at East Greenwich.|
|Photo courtesy National Archives
The first Gallaudet D-4, S/N A:2653, which crashed killing Lt. (j.g.) Arthur F. Souther, U.S.N. July 19, 1918. Note the small stub fin above and below the fuselage which was not used on D-4 number 2. Both D-4s were initially painted Navy gray overall.
|Another Gallaudet Drive design was acquired by the U.S. Navy, the D-4, with two being ordered in February 1918. The D-4s were approximately the same size as the D-1, but were powered by a single 400 H.P. Liberty engine. The first D-4 crashed in July 1918 as a result of an elevator control horn failure, killing the pilot., Lt. Arthur Souther.|
|Photo courtesy U. S. Navy
The second Gallaudet D-4, S/N A:2654, in September 1922. For the Curtiss Marine Trophy Race in October 1922 the forward cockpit was faired over and the racing number "3" was painted aft of the propeller.
|The second D-4 was successfully flown in October 1918 and was accepted by the Navy in April 1919. This D-4
was an entry in the Curtiss Marine Trophy Race held in Detroit, Michigan as part of the National Air Races on October 8, 1922. Lieut.
W. K. Patterson was the pilot, but he had to drop our of the race after the fifth lap due to the propeller breaking. It had apparantly been
hit by something thrown up in the water spray.
There were no further models of the D series constructed after the D-4s but Gallaudet carried designs in the series to at least the D-14. The model designation "D" was used for Gallaudet Drive designs only. These designs, as shown in the table, were of almost every conceivable type; seaplanes, landplanes, biplanes, monoplanes, triplanes, fighters, bombers, reconnaissance, airlineers, mail planes. In most cases only the general arrangement and balance diagram drawings and general performance calculations were made. On the D-6, D-9 and D-11 designs, however, the complete design work was performed. Construction actually commenced on the D-9. and D-11 for the Navy before the contracts were cancelled as part of the economy programs after World War I.
|Photo courtesy C A H A
One of the Gallaudet-designed and built geared-engine nacellese for the Navy's Giant Boat, running up on the test stand at the Gallaudet plane, mid-1921. Points of interest are the nacelle's large size, the wing root opening and the engine positions: two forward side-by-side engines and one aft engine--shown by the exhaust pipes..
The story of the Gallaudet Drive would be incomplete without mention of its big brother, the
"Gallaudet Multiple Drive." This was a giant power package which Gallaudet designed and built for the Naval Aircraft Factory, Giant
Flying Boat (G boat for short). The G Boat was a 150 foot wing span triplane, weighing some 65,000 lbs., and of similar configuration to
the Navy-Curtiss NC flying boats. It was powered by nine 400 H.P. Liberty engines, grouped three to a streamlined engine nacelle. The
three engines in each Gallaudet-designed nacelle were geared to drive a single 18 foot diameter propeller, either singly or in any
combination. The propeller was arranged in a tractor configuration, but there was a non-rotating streamlined fairing, comprising some
11% of the nacelle length, forward of the propeller, and the blade area near the hub was covered by a ring, similar to the D-model aircraft.
The three Gallaudet nacelles were completed, stand tested and shipped to the Navy in the summer and fall of 1921.
Unfortunately, the G boat airframe was not completed, due to the economy axe, and the final product of the Gallaudet
Drive concept was unable to prove itself in flight.
The author expresses his appreciation for assistance with this article to Mr. Lee Peason, Capt. Ralph S. Barnaby, U.S.N. (Ret), Mr. Felix S. Russoll and Mr. Filip Bjorklund