Subject: Number Fifty-Four in the Series--Vultee XP-54

From: [email-masked]
Date: 3 Mar 93 17:47:12 GMT

>From [email-masked]

The Vultee Aircraft Corporation was very largely the brainchild of 
Gerard Vultee, formerly chief engineer at Lockheed Aircraft 
Corporation during the time that Lockheed was owned by Detroit 
Aircraft.  When Detroit Aircraft went belly-up, Vultee was out of a 
job.  Eventually, he went off on his own in pursuit of financial 
backing for some ideas he had for a single-engine passenger monoplane.  
Vultee attracted the attention of the "boy wonder" of Wall Street, 
Errett Lobban Cord, who already owned or controlled several airlines, 
automobile manufacturers, and aircraft companies.  With $50,000 in 
cash (sounds like small potatoes today :-) ), Cord founded the 
Airplane Development Corporation in January 1932, as a subsidiary of 
the Cord Corporation.  Vultee was established as chief engineer of 
this new company.  In 1934, the ADC was reorganized as a division of 
the Aviation Manufacturing Corporation, which was in turn a subsidiary 
of the Aviation Corporation, which had recently been taken over by 
Cord in a stock deal.  The Aviation Corporation is best known today as 
being the parent company of what later became American Airlines.  
Vultee became a vice-president of the ADC, but retained his title as 
chief engineer.  In 1936, the ADC moved its plant to Downey, 
California.  In 1937, this plant was renamed the Vultee Aircraft 
Division of the Aviation Manufacturing Corporation.  

Gerard Vultee and his wife were killed in a plane crash in January 
1938.  He was succeeded as chief engineer by Richard Palmer, who had 
worked for a time on the Hughes H-1B racer.  A syndicate bought out 
Cord's interest in the company, and a California investment banker 
named Richard Millar was brought in as vice-president.  He moved up as 
president when Vultee Aircraft Inc. was established in 1939 to 
acquire the assets of the Aviation Manufacturing Corporation.  

On November 27, 1939 the USAAC issued Circular Proposal R-40C, which 
called for a fighter that would be much more effective than any 
extant--with a top speed, rate of climb, maneuverability, armament, 
and pilot visibility, all of which would be far superior to those of 
any existing fighter.  In addition, the fighter was required to have a 
low initial cost and had to be easy and inexpensive to maintain.  The 
Army specifically mentioned in R-40C that they would consider aircraft 
with unconventional configurations.  

No less than 50 responses came in.  Many of them were quickly ruled 
out, but by the end of 1940, four designs were considered sufficiently 
worthy of further study.  These were designs submitted by Bell, by 
Curtiss, by Northrop, and by Vultee.  

The Vultee Aircraft Corporation's only previous venture into fighter 
design had been the Model 48 Vanguard, which had been unsuccessful in 
attracting any Army production contracts.  Nevertheless, Richard Palmer's 
team at Vultee came up with the proposal which was judged the best of 
the entrants.  An initial Army contract covering engineering data and 
wind tunnel models was issued on June 22, 1940.  A contract for one 
prototype was issued on January 8, 1941 under the designation XP-54.  
A second XP-54 was ordered on March 17, 1942.  

The serial numbers of the two XP-54s were 41-1210 and 41-1211.  Odd 
that these two planes should have consecutive serial numbers when they 
were ordered more than a year apart.  However, it is obvious that both 
these numbers definitely were used by XP-54s, since I have books 
containing photos of both the first and the second XP-54s.  Their tail 
numbers (11210 and 11211) can clearly be seen in the photos.  However, 
one of the lists of serial numbers that I have indicates that the 
serial number 41-1211 was actually allocated to a BT-13A Valiant basic 
trainer.  To compound the mystery, some sources list the serial number 
42-108994 as being assigned to an XP-54.  It is not clear to me as to 
the reason for the discrepancy, but here's a guess: Since the second 
XP-54 was ordered over a year after the first, and would be expected 
to have a serial number from the next fiscal year, the second XP-54 
was duly assigned the number 42-108994.  Perhaps in order to give the 
two prototypes consecutive tail numbers, the number 41-1211 might have 
been transferred from the BT-13A and reassigned to the second XP-54.  
Anyone have any further information? 

The XP-54, designated Model 84 by Vultee, was a twin-boom, 
low-mounted, inverted gull-wing monoplane powered by an engine mounted 
in pusher configuration.  The engine was to be the Pratt & Whitney 
X-1800-A4G (military designation H-2600) twenty-four cylinder 
liquid-cooled engine offering a power output of 1850 hp and driving a 
set of contra-rotating pusher propellers.  The Model 84 was actually 
an outgrowth of an earlier Vultee proposal known as Model 78, which 
had a similar configuration but was to be powered by a unsupercharged 
Allison V-1710 liquid-cooled engine.  The single-seat cockpit was 
sited in the center section of the bullet-shaped fuselage.  Magnesium 
alloy construction was to be used throughout the fuselage.  A tricycle 
landing gear was fitted, with the nosewheel retracting into the 
fuselage and the mainwheels retracting into the booms.  

The center wing section was designed around the newly-developed NACA 
"ducted wing", in which the airflow was taken in via narrow slots in 
the wing leading edge and directed over the oil and coolant radiators 
and then to the intercoolers and eventually fed into the engine via 
ducts in the wing trailing edge.  The landing flaps were so designed 
that their secondary function was to regulate the airflow through the 
coolers.  This innovation made it possible to house the coolant 
radiators and the intercooler entirely within the wings.  

The original mission of the XP-54 was envisaged to be low- and 
medium-altitude combat.  Six 0.50-inch machine guns were to be mounted 
in the nose.  The estimated maximum weight was 11,500 pounds, and 
maximum speed was expected to be no less than 510 mph at 20,000 feet, 
taking six minutes to reach that altitude.  

On September 7, 1940, the USAAC announced to Vultee that they were 
changing the mission of the XP-54 from that of low-level combat to 
that of high-altitude bomber interceptor.  This change necessitated 
the development of a pressurized cockpit and the installation of 
turbosupercharging equipment.  Armament was changed to a pair of 37-mm 
T-12/T-13 cannon with 60 rpg and twin 0.50-in M2 machine guns with 500 
rpg, all mounted in the nose.  The Army also required the fitting of 
heavy armor protection for the engine and pilot.  All of these changes 
caused the estimate gross weight to creep up to 18,000 pounds.  

The pressurized cockpit requirement, combined with the considerable 
height of the aircraft from the ground, made cockpit entry and exit a 
problem.  In order to attack these problems, a unique solution was 
evolved--a pilot seat which functioned as an elevator.  In order to 
enter the aircraft, the seat was electrically lowered from the bottom 
of the aircraft by a switch mounted on the outside of the plane.  The 
pilot would sit down on the seat, throw a switch, and the seat would 
electrically raise itself up into the aircraft until it reached the 
flight position.  Flight control cables were routed around the opening 
in the floor, and an inverted U-column was used to support the pilot's 
control wheel.  This ventral access was also valuable in that it made 
possible the design of a fixed cockpit canopy, which simplified the 
problem of making a pressure-tight seal.  In an emergency (assuming 
sufficient altitude were available), the elevator seat assembly would 
be catapulted downward clear of the propeller, making the XP-54 the 
first American fighter to be fitted with an ejector seat.  

The nacelle-type fuselage incorporated yet another unusual feature.  
Because of the different muzzle velocities of the cannon and machine 
guns, the entire nose section was moveable so that direction of fire 
of the machine guns could be elevated by as much as three degrees or 
depressed by as much as six degrees without changing the flight 
attitude.  The cannon were fixed and did not move.  The movement of 
the nose section and the machine guns was controlled by a special 
compensating gunsight.  The management of these differentially- 
pointing guns probably would have been a real nightmare.  

In October 1940, Pratt & Whitney discontinued all work on its X-1800 
engine, and Vultee decided to substitute the 2200 hp twenty-four 
cylinder liquid-cooled Lycoming XH-2470 in its place.  The Lycoming 
engine was still under development for the Navy at the time.  The 
Lycoming engine was to be fitted with a turbosupercharger, in view of 
the XP-54's newly-assigned high-altitude role.  

With all of these changes, it came as no surprise that the delivery 
date slipped substantially from the promised date of July 1942.  The 
first XP-54 (41-1210) did not, in fact, fly until January 15, 1943, 
when test pilot Frank Davis took it for a 31-minute flight from Muroc 
Dry Lake (now Edwards AFB).  This flight went fairly uneventful except 
for the malfunction of the Curtiss propeller.  It was subsequently 
replaced by a Hamilton-Standard unit.  By March 11, ten flights had 
been made, but it was clear that performance was substantially below 
that guaranteed.  In addition, the engine showed metal traces in the 
oil, and the aircraft was returned to Downey for an engine change.  86 
more flights were carried out at Ontario AFB, California, and on 
October 28, the XP-54 was flown to Wright Field for service testing.  
However, the Lycoming engine again developed serious problems, and the 
entire engine had to be returned to the manufacturer for repairs.  
Repairs turned out to be prohibitive, and the engine was scrapped.  

Some sources claim that the XP-54 was known under the popular name 
"Swoose Goose" while it was at Wright Field.  I have no idea of where 
this name came from or what it means.  

By that time, the continual troubles with the Lycoming H-2470 engine 
had led the Navy to abandon the program.  The XP-54 was therefore left 
without an engine.  A proposal to adapt the Wright R-2160 Tornado 
radial engine to fit the XP-54 airframe was briefly considered, the 
project being redesignated P-68.  However the Tornado engine also 
failed to achieve production, and the P-68 project was abandoned.  
Although it appeared possible to install the Allison W-3420 in the 
XP-54 without major structural changes, the delay and expense involved 
in making such a change resulted in the decision being made not to try 
to introduce the XP-54 into quantity production.  There was even 
thought given to the installation of a jet engine in the XP-54 
airframe, but such a proposal was rejected on the grounds of cost.  

The second XP-54 (41-1211) was delayed by the need to change from two 
Wright turbosuperchargers to a single experimental General Electric 
XCM model.  Consequently, by the time it was ready for flight, all 
hope of quantity production of the XP-54 had been abandoned.  The 
second XP-54 finally took to the air on May 24, 1944, when it was 
taken on a 20-minute flight from Downey to Norton AFB, California.  
The engine/turbosupercharger combination was found to be 
unsatisfactory and they were returned to the manufacturer.  Although 
another engine was fitted to the second XP-54, it was never flown 
again.  The nose section was sent to Elgin AFB for armament tests (the 
guns were never fired from the air).  The rest of the airframe was 
scrapped.  The first XP-54 was static tested to destruction at Wright 
Field.  

The XP-54 was the last project that the Vultee corporation carried out 
for the USAAF under its own name.  In June 1943, Vultee Aircraft, Inc.  
merged with Consolidated to form Consolidated Vultee Aircraft 
Corporation.  Although the name of the new conglomerate was contracted 
to "Convair" internally, this name was not officially registered until 
1954 when Convair became a division of General Dynamics.  

Specs of the XP-54: 

Maximum speed: 381 mph at 28,500 feet, 290 mph at sea level.  Initial 
climb rate: 2300 feet per minute.  Climb to 32,100 feet in 27.7 
minutes.  Service ceiling: 37,000 feet.  Weights were 15,262 pounds 
empty, 18,233 pounds normal loaded, and 19,337 pounds maximum.  
Dimensions were wingspan 53 feet 10 inches, length 54 feet 8 3/4 
inches, height 14 feet 6 inches, and wing area 455.5 square feet.  

Sources: 

  The American Fighter, Enzo Angelucci and Peter Bowers, Orion, 1987.  

  General Dynamics Aircraft and their Predecessors, John Wegg, Naval 
  Institute Press, 1990.  

  War Planes of the Second World War, Fighters, Volume Four, William 
  Green, 1964.  

Joe Baugher       AT&T Bell Laboratories    2000 North Naperville Road 
		  Naperville, Illinois 60566-7033.   (708) 713-4548