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From May, 1945 Model Airplane News.
TO AMERICAN engineers, both those engaged in research for private manufacturers and those officers and civilian technicians of the Army-Navy and the government, the contest with their counterparts in Germany and Japan has been unrelenting since September 3, 1939, when England went to war with Germany.
The battles are fought by soldiers, land, sea and air, but the weapons of this war are forged by research engineers, and this scientific war has been and is being as keenly and desperately fought as those battles in the front lines.
Unfortunately for the news-hungry layman, this phase of the war is secret. War plants are guarded, workers are carefully identified, their movements even within the plant carefully prescribed, and data and information religiously protected.
Most news of the enemy’s scientific developments is rapidly disseminated and the newspapers and magazines rush the latest revelations into print. The past few war years in particular have witnessed a deluge of news of new Nazi scientific weapons: incendiary bombs, aircraft cannon, aircraft rockets, robot bombs, jet-propelled fighters, etc.
This unfolding of Nazi air weapons has created and nourished something akin to anxious envy by the American people, and in many cases honest alarm over our prospects for winning this scientific battle.
But our scientists have been powerless to balance this one-sided news-picture by revelations of our own countermeasures and new inventions. Such publicity would undo all the efforts that have been made to keep such information a secret.
We are told how good our enemy scientists are but we cannot be told the value of our own scientists—such is the paradox of this military information picture. It is psychological warfare in reverse: We are forced to propagandize ourselves!
However, as time and situation permit, certain American devices are revealed—normally those outmoded by later developments or by a series of unavoidable events, made fully known to the enemy.
One or the other of these has been the case with radar, American aircraft rockets, Allied jet propulsion planes, the Norden bombsight, electronic flight control equipment, remote-control turret systems, the flexible aircraft cannon, 12,000 lb. bombs, etc . . . and more recently a number of single-seat fighter planes of heretofore radical design including the Vultee XP-54, our Plane on the Cover this month.
The XP-54 was designed and produced to study the problem of pusher design and to determine the relative advantages and disadvantages of the type. With location of engine and propeller in the rear of the fuselage much of the troublesome and complex flow within the prop wake is eliminated, although new aerodynamic factors are introduced with almost equally complex behavior.
Vision for the pilot is considerably improved in the pusher design, however, and installation of heavy armament in the nose is simplified. The XP-54 was a research problem by Army Air Forces and Vultee engineers and is typical of several similar designs, all weapons in the hidden scientific battle with the Luftwaffe.
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The Vultee XP-54 evolved as a product of the continuous program of high speed aircraft research and development begun by the late Gerard F. Vultee, whose name is a part of the American aviation legend. Vultee was a member of a small but serious band of young men who brought science to the aviation field where previously the cut-and-try method of nervy experiment existed.
“Jerry” was an intensely serious young man whose entire life was wholly devoted to aviation as an engineering science. His father was Henry V. Vultee, whose administrative ability carried him to the post of Treasurer of Lackawanna Iron and Steel.
Jerry’s early life is no story of poverty, but he was no playboy, and 1921 found him one of the first graduates in aeronautical engineering at California Institute of Technology, one of the nation’s finest technical schools demanding the highest possible scholarship.
Slide rules and graphs weren’t enough for Jerry’s aviation interest during school days, so with a classmate, Louis Keasling, he designed and constructed a utility glider, the T.A.L., which actually flew and produced Jerry’s first sight of his own airplane in the air.
But his graduation as an aeronautical engineer in 1921 created little stir in the American aviation world which was busy boarding up its war-bloated factories and fighting the predicted deluge of surplus foreign war-built airplanes. His slide rule remained in its case while Congress was holding no less than 20 separate inquiries into the aviation industry during the postwar years.
Finally, in 1926, his first break came and he was hired as a draftsman by Donald Douglas. The Douglas Engineering Department was hard at work on the O-2 observation biplane for the Army, the T2D-1 torpedo seaplane for the Navy, and versions of the M-2 mail-plane.
Vultee had been with Douglas only a few days when he struck up a friendship with John K. Northrop, whose experience with Douglas went back to the World Cruisers in 1923 and to the Loughead Aircraft Manufacturing Co. in Santa Barbara, Calif., during the war.
Jack and Jerry found much in common: a serious type of interest in aviation in stark contrast to the carefree high adventure aura pervading the flying aspects of the game during the period.
Late in 1926 Jack’s old boss, Allan H. Loughead, invited him to join in establishing a new firm, later to become world famous as the Lockheed Aircraft Corp. In January 1927, Northrop moved to new quarters in Burbank, Calif., as Chief Engineer and he brought Vultee along as Project Engineer.
The pair engineered the radically new Lockheed Vega monoplane which was built and flown in less than 7 months; it immediately proved the value of scientific aircraft design, a principle Vultee was to advance until his death, and one Northrop is destined to carry to unbelievable fulfillment.
In the summer of 1928 Northrop resigned to start his own firm and Vultee was appointed Chief Engineer for Lockheed. Jerry designed and developed the famed Lockheed Orion, one of the fastest planes of its day. It featured low-wing design and a fully retractable landing gear, innovations at the time.
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|Lockheed Orion; designed by Jerry Vultee.|
The depression brought a heavy financial strain on Lockheed, however, and it was purchased by the Detroit Aircraft Corp., a holding firm which soon included Ryan Aircraft, Parks Aircraft, Parks Air College, Eastman Amphibian and Aircraft Development, the latter constructors of the metal-clad dirigible.
James Work, who was later to form Brewster Aeronautical Corp., was made Vice-President and Gerard Vultee continued as Chief Engineer until 1932 when he found an opportunity to form his own firm.
E. L. Cord, automobile and engine financier whose holdings also included airline, aircraft and propeller interests, agreed to back Vultee in the new venture and the Airplane Development Corp. was formed. A small hangar was rented on Grand Central Air Terminal, Glendale, Calif., and Jerry began design work on a single-engine high speed, all metal transport.
The Vultee V-1 was an 8-passenger, 10-place low-wing monoplane design powered by the largest engine available, the big 710 hp Wright Cyclone radial, fully enclosed in a long chord cowl.
Jerry alternated between his design board and the California beaches. A champion swimmer, he once received a watch from the Los Angeles Athletic Club for a heroic rescue and participated in many L.A.A.C. swim meets with such experts as Duke Kahanamoku, Owen Hale and others. It was while surfboarding that he met vivacious, blonde Sylvia Parker and married her in December, 1934.
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|Vultee V-1A transport was used by airlines and private operators.|
The newly completed V-1 was rolled from the hangar and Jerry and his new bride climbed in with Leland S. Andrews and took off for Mexico and a honeymoon. The 1,670 miles between Los Angeles and Mexico City was covered in 8 hrs. 9 min., a new inter-city record.
From prop to tail wheel the sleek transport was a champion, and on January 15, 1935, Jimmie Doolittle and 2 passengers streaked to a new Coast-to-Coast transport record of 11 hrs. 59 min. in an American Airlines V-1A. A month later, on February 20, 1935, American Airlines Capt. Leland S. Andrews flew the same plane from Los Angeles to Washington, D.C., in 10 hrs. 22 min. 54 sec., an average speed of 221 mph!
The government forbade use of single-engine transport planes on the airlines, but Vultee’s orders from private owners continued and more hangar space was rented to provide for tools and jigs.
Jerry redesigned the speedster into a 2-place military attack bomber and the deadly craft quickly found favor with foreign governments. The V-11, as it was known, was constantly improved and a 3-seat version with belly gun position was perfected. Among the purchasers of this powerful weapon were the U.S. Army Air Corps (YA-19), Turkish, Chinese, Russian, Brazil and other Air Forces.
In 1936, with increasing orders for the V-11 on the books, Jerry built a new plant in Downey, Calif., and changed the name of the firm to Vultee Aircraft, Inc. With a genuine production line for the first time, Jerry rolled bombers out of the factory at an increasing rate.
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|Vultee Y1A-19 used by U.S. Army, Chinese, Turkish Air Forces.|
One of his largest customers was the Amtorg Trading Corp., a division of the Russian Government, which purchased 40 attack-bombers together with licensing rights, jigs and tools. The backlog mounted to 4 million dollars so Jerry found it necessary to devote more and more of his time to the export phases of his firm and soon gave up designing altogether.
Business carried Jerry to New York during December, 1937, and he took Sylvia along with him. While returning to Los Angeles, on January 29, 1938, their plane crashed in a snowstorm near the summit of Mt. Wilson, and Jerry and Sylvia were killed instantly.
Back at the plant, his assistants were stricken by the tragedy but as the weeks passed they knew Jerry would have wanted them to go right on with his work. And go ahead they did.
The Vultee 48 Vanguard single-seat fighter was designed and flown with a radial, air-cooled engine fully enclosed in a cowling similar to those used on liquid cooled engines. This installation proved a success and cooling was satisfactory in every detail.
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|Original Vultee Model 48 featured burled double-row air-cooled engine.|
A conventional cowling was installed on the production models, however, to eliminate the necessity for an expensive crankshaft and crankcase extension.
A Swedish order for 100 of these 48-C models was on hand when war broke out. Great Britain agreed to take them and then it was decided to send them to China. The Army Air Forces finally requisitioned them as model P-66 and many are still in use as fighter-trainers.
Model 51 Valiant proved a stable, maneuverable trainer and Model 54, a development of it, was ordered by the Army as the BT-13 and BT-15 and by the Navy as the SNV-1. To date more than 15,000 of these sturdy basic trainers have been produced.
|Vultee BT-13C is standard Army trainer with thousands now in use.|
|Vultee SNV-1 Navy trainer.|
Model 72 Vengeance dive-bomber was produced for the British Royal Air Force and was one of the first of America’s warplanes to feature new battle-tested requirements: heavy firepower, self-sealing fuel tanks, armor plate and other tactical devices. Its latticed dive brakes were the first installed on an American design and the Vengeance went into quantity production at Vultee’s Downey plant.
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The financial structure of Vultee has always been a subject about which much is rumored but little is known.
E. L. Cord has played a large role in the development of American aviation, but like most such figures he has religiously remained in the background. His Aviation Corp. (owned since 1937 by Victor Emanuel) has gone through numerous changes ranging from its status as a truly giant enterprise in the early ‘thirties to a conservative group of aircraft accessory and special equipment plants today.
During the early ‘thirties, Cord was able to put Smith Controllable propellers on Lycoming engines, place them in Stinson airplanes and fly them on American Airlines, all branches of his own corporation.
In 1939 and 1940 Cord’s successor, Emanuel, consolidated many of his holdings into Vultee Aircraft, Inc., by designating the Stinson plants at Wayne, Mich., and the new Stinson plant at Nashville, Tenn., Vultee Divisions.
When quantity production of the new Vengeance got under way at Downey, the Nashville Division was also allocated to the work and a sub-contract for complete airplanes awarded Jack Northrop’s Hawthorne, Calif., plant. (Who could have foretold that 15 years after their first meeting, Northrop would be building Vultee airplanes?)
In 1940 work was begun on a radically new single-seat fighter plane at Vultee’s Engineering and Development Division at Downey.
It was designed around the Lycoming liquid cooled engine produced by the Lycoming Division of Aviation Corp. As a result of preliminary tests of this new engine, the Liquid Cooled Division of Aviation Corp. was formed in 1942 to carry out extensive design research on liquid cooled, high horsepower engines for the U.S. Navy.
Results of numerous tests on the “tractor vs. pusher” problem have been so divergent as to prove little in the way of definite advantages for either type. Most tests have been applicable only to an individual design.
In the tractor, the presence of the fuselage behind the pilot robs the slipstream of from 2% to 3% of its efficiency. Although this loss is eliminated with a pusher design, the acceleration of the stream forward of the propeller (considered around 31% increase) must necessarily increase fuselage drag as well as wing drag in the region.
Due to the fact that the pusher propeller normally works in turbulent air, formation of the compressibility burble is delayed and thrust at slightly higher tip speeds may be maintained.
The rolling moment of the tractor arrangement induced by the propeller vortex is eliminated by the pusher, but torque rolling moments may be slightly increased due to the absence of the propeller vortex which normally works against torque.
It may easily be seen that the relative efficiencies of the two arrangements are a “nip-and-tuck” affair with the care given to an individual design normally determining its value.
The chief advantage of the pusher remains the improved vision and comfort for the pilot (or crew) being placed forward.
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|Vultee XP-54 3-view. (click button for larger size)|
|2076x2973 size available. to open in new window.|
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Another innovation in the XP-54 is the use of magnesium alloy as a structural material and the successful application of welding to this highly inflammable material. The fuselage of the XP-54 is of welded magnesium as are the tail booms. Stainless steel is used along the aft fuselage upper surface in the vicinity of the dual exhaust stacks aft of the pilot’s enclosure.
The pilot gains entrance to the cockpit through an “elevator” which lowers the seat down to him, after which he is drawn up into the fuselage. Emergency exit is provided by dropping this “elevator” from the airplane, thus throwing the pilot clear of the propeller and tail booms.
Due to the slim fuselage, the nose wheel is retracted forward, the main gear moving aft into the tail booms. No details of armament or equipment have been released but we may rest assured that the Vultee XP-54 mounts heavy cannon and numerous .50 caliber machine guns.
The plane is now at Wright Field undergoing extensive flight tests which are augmenting the already voluminous data obtained.
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In December, 1941, Major Reuben Fleet, founder and long time guiding hand of Consolidated Aircraft, agreed to sell his holdings to a group headed by Victor Emanuel of Aviation Corp.
With the consummation of these negotiations, Consolidated Vultee Aircraft Corp. was formed to become one of the largest aircraft manufacturing groups in the entire world. Today, this mammoth firm is operating plants in Downey and San Diego, Calif.; Tucson, Ariz.; Dearborn, Mich.; New Orleans, La.; Williamsport and Allentown, Pa.; Louisville, Ky.; Nashville, Tenn.; Elizabeth City, N.C., and Miami Springs, Fla.
And so, 45 years after his birth and 7 years after his death, Gerard F. Vultee’s name is an integral part of a giant American aviation enterprise which has procured every possible type of military airplane and has just announced the largest airplane ever constructed in the history of aviation!
More than 101,000 people have been at work in this tremendous manufacturing project and planes of every description are now flying and fighting with Jerry Vultee’s name.
That’s the way he always dreamed of it and, perhaps, right now he’s flashing that tight, slightly drawn grin of his, feeling just a glow of pride and musing about that’s the way he wanted it and that’s just how it is!
END OF ARTICLE.
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EDITOR’S NOTE: THE FOLLOWING ARTICLE IS ADDED FOR MODEL MAKING ENTHUSIASTS.
Test the pusher theory by building this Plane on the Cover model.
by EARL STAHL
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THE search for superior fighting aircraft is an endless one for all warring nations.
Constantly pouring from engineers’ drawing boards and from aeronautical laboratories is an endless stream of ideas ranging from minor modifications for successful craft already at grips with the enemy to radically new craft boldly striving for supremacy over anything the foe can hurl into the conflict.
In reality, only a small fraction of the ideas conceived prove wholly practical in the end. Such is true of literally thousands of designs for aircraft submitted to the air arms of our Army and Navy.
Usually from competitions in which manufacturers are invited to offer designs for specific types of craft, the armed forces select several of what appear to be the most promising projects for actual construction and exhaustive tests. Of these only a very few ever attain quantity production for eventual action in enemy skies.
Reasons for a plane’s failure to make the grade are numerous and varied. Perhaps the new ship is of inferior performance, below the expectations of the designers. Possibly it is possessed of unstable flight characteristics, spins too viciously, or is abnormally dangerous.
Occasionally an otherwise satisfactory type is plagued by grief brought about by a troublesome engine or faulty accessories. Many times, volume construction or cost difficulties doom the ship to oblivion.
On the other hand, the design may be entirely satisfactory but is shelved because its small margin of superiority over existing types makes reconversion impractical.
Such a plane is the Consolidated Vultee XP-54. This unconventional fighter has been under test by the Army Air Forces but was discarded in favor of fighters now in, or going into production. No reason for abandonment of the XP-54 has been given.
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EDITOR’S NOTE: In reality, aircraft like the Vultee XP-54 and the twin engine McDonnell XP-67 and were contracted with a small likelihood of success (both also used unproven engines). The government allocated small amounts of money for radical designs which demonstrated interesting and potentially useful concepts in actual flight.
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A plane of very striking appearance, it incorporates a number of unusual features. Driving the four-bladed pusher propeller is an experimental Lycoming liquid cooled engine of great power.
One of the pet gripes of pilots who condemn pusher aircraft such as this one (and justly so!) is that when leaving the ship in an emergency, the body would in all probability be hurled into whirling propeller blades. This problem was solved in the XP-54 by equipping it with an ejector which casts the pilot beyond the arc of the prop and also the tail surfaces.
Situated midway on the pod like fuselage, forward of the engine and inverted-gull wing, the pilot’s cockpit affords unusual visibility, a decided asset. It is pressurized to enable the pilot to hunt and fight at great altitude. Four cannon of probably 20 mm. bore are provided for in the long nose.
Because of its unusual yet practical design, the Vultee XP-54 makes an excellent flying scale model. The drawings are accurately scaled and will serve as the basis for both a flying or exhibition model.
Construction of the miniature will not be difficult if drawings and details sketched here are followed closely. Balsa wood is used throughout and quick drying colorless cement is the adhesive. Incidentally, the reward for neat, accurate work is finer appearance and better flights!
The model’s large size and odd shape made it necessary to extend the side and top views over two pages each. Simply match the pages together so work can be done atop them since most parts are shown full size.
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|Earl Stahl, Vultee XP-54 Rubber Plan Plate 1. (click button for full size)|
|2145x3115 size available. to open in new window.|
|Earl Stahl, Vultee XP-54 Rubber Plan Plate 2. (click button for full size)|
|2133x3112 size available. to open in new window.|
Crossectional shape of the fuselage is cylindrical so most bulkheads are circular. The keel and bulkhead method of construction is employed and each of the four keels (top, bottom and two sides) and the bulkheads are cut from 1/16” sheet balsa. Two of each bulkhead type are cut except No. 3 which requires eight.
To assemble, pin top and bottom keels in place over the side view, attach half the bulkheads to their respective positions and cement a side keel to place. When dry, remove from the plan and add the rest of the bulkheads and remaining keel.
Stringers are 1/16” sq. firm stock and are fitted to the notches. Where the wing fits in, curved 1/8” sheet pieces are fitted exactly as shown to conform to the top surface of the wing; place these accurately since they aid in aligning the wing accurately.
At front and rear of the fuselage, laminated pieces of 1/8” sheet are shaped so as to fit to bulkheads No. 1 and No. 7. The nose block has a .035 diam. music wire hook in it to hold the rubber motor, and a tiny loop in the front into which a mechanical winder can be hooked for storing up maximum power when flying.
The nose is removable as is the tail plug which fits into the laminated tail block. A disc of 1/32” plywood forms the front of the plug and the rest is laminated squares of 1/8” sheet. Drill a hole through the plug for the prop shaft and cement washers to either side.
Only the right wing is shown so it is best that the left wing plan be made at once.
Ribs are 1/16” sheet accurately cut to the shape given. The main spar is 1/16” x 1/8” balsa while the landing gear one is 1/16” x 3/16”.
Build right and left panels individually and without dihedral. Once the frames are complete, spars and leading and trailing edges are cracked and the tips raised 2-1/8” while the inner section remains flat; re-cement the joints well.
Booms fit to wing ribs No. D and are built like the fuselage except that the center keel is one frame trussed with 1/16” sq. strips for greater strength. Lay out the keels over the side view and then add the bulkheads and stringers which are 1/16” sq. strips. Remember two booms are required.
If wings and booms have been made accurately, they will assemble correctly without too much trouble. Note on the side view how they sweep upward in the rear (about 3° measured relative to the flat bottom of the rib and the center stringer of the boom), and on the top view how they tow in.
Easiest way to assure complete accuracy is to lay out the booms on the wing drawings and assemble them over these layouts. Be sure to attach them firmly using plenty of cement.
Tail surfaces are easily made from 1/16” x 1/8” outline strips and 1/16” sq. ribs. Note how additional 1/16” sq. strips are placed at each side of each rib to strengthen them and give the streamline crossection.
The landing gear must be very strong and the wire struts suggested are very practical. The front fork is made in two pieces from wire of about .035 diam. and are soldered together. With needle and thread sew the front strut to bulkhead No. 4.
Rear legs are of similar music wire and the tops are bent to join ribs No. D and the spar. Be sure to make a right and left one and then lash them in place with thread. Coat the adjacent areas to the landing gear attachments with plenty of cement.
Scale effects for improving the landing gear appearance are easily represented with rubber tubing and scraps, but this is not done until later.
The following sequence is suggested as best for continuing construction of your XP-54. Cover the wings from rib A outward including the booms which were previously attached. Colored tissue is best used since it is both attractive and light and thin dope or banana oil is the adhesive.
When covering the fuselage, use a number of small pieces of tissue neatly lapped to help avoid unsightly wrinkles. Incidentally, don’t cover any of the area below the wing mount strips until after the wing is in place.
Tail surfaces are covered using a separate piece of tissue for each side of each part. The covering may be tightened by lightly spraying with water at this time, but apply no dope until the ship is entirely assembled.
Wings are assembled by slipping them into position and cementing fast, but first be sure of their proper placement. It is suggested that the fuselage be blocked perfectly level with the bottom exactly 7/16” above the level surface of the work bench.
Now, with the lowest portion of the boom keels (under the gull of the wing) touching the bench, the dihedral at each tip measuring 1-1/8” and the extreme rear of the booms raised 11/16”, the alignment should be correct.
All this may sound difficult but it really isn’t; use small blocks of wood, pins, bottles and ingenuity to hold the parts in place to achieve the proper setup. (Note: holes drilled in the assembly table for the landing gear to slip through permits the plane to be assembled in this manner; otherwise all dimensions should be lengthened equally to clear the gear above the layout table.)
While the little ship is jigged up, cement the stabilizer fast noting that a line through the leading and trailing edge of it is parallel to the center stringer of the boom. Rudders are likewise cemented on, not at the angle of the booms but parallel to the line of flight (centerline).
All uncovered parts should now be finished and then one or two coats of clear dope applied.
Now for the lesser items. Wheels are easily made from balsa or they may be purchased; glue washers or bearings to them so they will revolve accurately.
For added realism rubber tubing of the correct diameter is slipped on the wire landing gear struts. Tiny auxiliary struts are slivers of bamboo, and the covers that close the wells when the gear retracts on the real ship are 1/32” balsa covered with tissue to match the model’s coloring.
The cockpit enclosure is thin celluloid (cleaned photo film) and it should be made in three sections to shape it properly; avoid cement smears when attaching to the model.
Cannon blisters, radiators and like details are made from wood scraps and black tissue.
Control surfaces are outlined with thin strips of black tissue. U.S. star insignia, numerals and the like may be made from colored tissue but decals are far less trouble.
A flying model requires an enlarged propeller, and details for the four-bladed one and spinner are given on the drawings. Use hard balsa for the prop and a soft grade for the spinner.
Music wire .035” in diameter is bent as indicated for the prop shaft. Be sure to place several washers between tail plug and prop so it will turn freely.
Six strands of 1/8” flat rubber should be right for most models, but with different weight ships this may vary. Lubricate the rubber with a mixture of tincture of green soap and glycerine to attain most power and longest life from the strands.
Skillful handling and correct adjustment are required to get maximum flight performance from any model. Select a
place where the ship will not get damaged while flying it—a branch of a tree or side of a building is scarcely a suitable landing place.
First make shoulder-high test glides adding weight to nose or tail to correct a tendency to stall or dive. Launching a pusher is a problem so rise-off-ground flights are in order.
Try a few turns on the rubber motor at first, gradually increasing the number as flights improve.
Offsetting the thrust line is an effective way of adjusting unstable power flight attitudes and controlling the amount of circle.
Treat your XP-54 with care and you will be rewarded with a fine flying, attractive miniature.