Subject: Number Sixty-Six in the Series--Vultee P-66 Vanguard

From: [email-masked]
Date: 3 May 93 16:29:20 GMT

>From [email-masked]

The Vultee Model 48 was an company-originated design evolved during the 
late 1930s by Richard Palmer, chief designer of the Vultee Aircraft 
Division of the Aviation Manufacturing Corporation.  The aircraft was 
intended for the export market, and was pattered after the H-1B racer 
which Palmer had designed for Howard Hughes.  The Hughes H-1B set a 
world landplane speed record of 352.388 mph in 1935.  

In late 1938, Palmer and his team were busily working on their Model 
48 project when the US Army announced a design competition for an 
advanced trainer.  Since a substantial Army order was anticipated for 
the winner of the competition, the Vultee Aircraft Division decided to 
enter the contest.  Palmer's team came up with the idea of using the 
work already done on the Model 48 as a basis for Vultee's trainer 
proposal.  

Eventually, the Vultee team evolved four separate and distinct 
aircraft designed to fulfill different military roles from this one 
basic design.  The four designs used the same basic tooling and 
featured the same wings, the same aft fuselage, and the same tail 
assembly.  Other details differed according to the roles assigned to 
the individual aircraft.  The four types carried the company 
designations BC-51, B-54, B-54D and P-48.  

The BC-51 was the designation given to the basic combat trainer which 
was eventually entered by Vultee in the USAAC competition.  However, 
the BC-51 lost out to the North American BC-2 in the trainer contest.  
Nevertheless, the Army bought the sole Vultee BC-51 under the Army 
designation BC-3.  

The B-54 was an advanced trainer design intended for export and the 
B-54A was a basic trainer version.  The B-54A eventually evolved into 
the famous BT-13 Valiant.  

The P-48 was the fighter version.  The designation "P-48" was a 
company designation, not to be confused with the USAAF's P-for-pursuit 
designation scheme.  Vultee put work on the P-48 on the back burner 
while they concentrated on the three trainer versions.  

The P-48, BC-51, and B-54 had the same fuselage center section and a 
retractable undercarriage, and the BC-51, B-54, and B-54D had the same 
wing outer panels which had a greater span but the same wingtip and 
root chord as those of the P-48.  

After the three trainers had been produced in 1939, Vultee returned to 
work on their original P-48 design.  The P-48 featured a steel-tube 
semi-monocoque fuselage, a two-spar wing, and a fully-retractable 
undercarriage.  It featured hydraulically-actuated split flaps.  The 
aircraft was all metal-covered, with the exception of the control 
surfaces.  The P-48's detachable outer wing panels shortened its wing 
span by six feet in comparison to the wings of the trainers.  At one 
time, an armament of no less than TEN 0.30-inch machine guns was 
envisaged, with two of the guns firing rearwards aimed by mirrors.  
However, this idea was abandoned during development and a more 
conventional layout of two 0.30-in guns in the cowling and four 
wing-mounted 0.30-in guns was adopted.  

The P-48 aircraft was to have been powered by a Pratt & Whitney 
R-1830-S4C4-G air-cooled radial engine rated at 1200 hp for takeoff 
and 900 hp at 15,400 feet.  According to the initial plan, the engine 
was to be enclosed in an orthodox cowling similar to that fitted to 
the Curtiss P-36.  However, during construction it was decided to 
switch to an unorthodox long and pointed cowling on order to reduce 
aerodynamic drag.  In order to accommodate the long and pointed 
cowling, the engine was fitted with a lengthened drive shaft.  Engine 
cooling was provided by a retractable air intake fitted beneath the 
nose immediately behind the propeller spinner.  The nose of the P-48 
looked a lot like the nose of the abortive Curtiss XP-42.  

The Model P-48 was given the civil designation NX21755, and was flown 
for the first time in September of 1939 by test pilot Vance Breese.  
The name *Vanguard* was chosen.  Unfortunately, the Model P-48 ran 
into the same sort of engine cooling problems that bedeviled the 
Curtiss XP-42.  After a few flights with the initial cowling 
configuration, the variable air intake underneath the nose was fixed 
in the open position and another scoop was added above the cowling.  
At the same time, the rudder area was increased.  Only limited flight 
testing had been completed when, on May 9, 1940, the Model P-48 
Vanguard was damaged in a mid-air collision with Paul Mantz's Lockheed 
Sirius during a landing at Vultee Field.  The impact severed one of 
the undercarriage legs, but test pilot Vance Breese succeeding in 
landing the Vanguard with little additional damage.  

The production version of the Model P-48 was to have been designated 
Model 61, but by the time of the P-48's landing accident it had 
already been decided to give up on the pointed-nose for the Vanguard, 
since the drag reduction that it provided was insufficient to justify 
the increased weight and the cooling problems that it caused.  
Consequently, the second prototype Vanguard, the Model 48X (NX19999), 
reverted to the orthodox radial engine cowling that had originally 
been planned.  The Model 48X made its first flight on February 11, 
1940.  The second prototype also differed from the first in having a 
compound wing dihedral with a break in the middle.  

The damaged first prototype was rebuilt with the originally-planned 
orthodox radial cowling, a modified main undercarriage, and a 
rearward-retracting tailwheel.  Provisions were made for twin guns in 
the upper fuselage decking and two wing guns.  

Some instability was encountered by the Model 48X during flight 
testing, and substantial increases were made in the areas of both the 
vertical and the horizontal tail surfaces.  The maximum speed was 358 
mph at 15,600 feet.  Initial climb rate was 3300 feet per minute.  
Service ceiling was 34,300 feet, and normal range was 738 miles.  
Weights were 4657 pounds empty and 6029 pounds gross.  Dimensions were 
wingspan 36 feet 0 inches, length 29 feet 2 inches, height 9 feet 5 
inches, wing area 197 square feet.  

On February 6, 1940, Vultee received an order from Sweden for 144 
Vanguards, the production version being given the company designation 
Model 48C.  The Flygvapen designation for the aircraft was J10.  The 
first production prototype bore the civilian serial number NX28300 and 
flew for the first time on September 6, 1940.  It was essentially 
similar to the Model 48X, but had an R-1830-S3C4-G (R-1830-33) engine 
rated at 1200 hp for takeoff and 1050 hp at 13,100 feet.  Armament 
consisted of four 0.30-in machine guns in the wings and two 0.50-in 
machine guns in the fuselage.  The military equipment added to the 
Model 48C caused the weight to go up-- weights were 5237 pounds empty, 
7100 pounds gross, and 7384 pounds maximum.  The extra weight caused 
the performance of the Model 48C to degrade in comparison with that of 
the Model 48X.  The maximum speed was 340 mph at 15,100 feet.  Initial 
climb rate was 2520 feet per minute, and an altitude of 19,680 feet 
could be attained in 9.2 minutes.  Service ceiling was 28,200 feet, 
and normal range was 850 miles.  Weights were 4657 pounds empty and 
6029 pounds gross.  Dimensions were wingspan 36 feet 0 inches, length 
28 feet 4 inches, height 9 feet 5 inches, wing area 197 square feet.  

Before any production aircraft could be delivered to their Swedish 
customer, the US government placed an embargo on the export of 
military aircraft to Sweden, fearing that they might fall into Axis 
hands.  Although the British had earlier rejected the Vultee fighter 
for their own use, they agreed to take over 100 of these aircraft 
under Lend-Lease as Vanguard Is.  RAF serials BW208 through BW307 were 
assigned to these aircraft.  The Vanguard I was considered as being 
unsuitable for combat use by the RAF, but it was considered 
appropriate for advanced training use by units based in Canada.  

In early 1941, Chiang Kai-Shek's Nationalist Chinese forces were being 
hard-pressed by Japanese air attacks, and were in desperate need of 
more combat aircraft.  So dire was their need that they were willing 
to accept just about anything that had wings.  On May 19, 1941, the 
British government agreed to release its Vanguards for supply to 
Chiang Kai-Shek's Nationalist Chinese forces.  The 144 Vanguards were 
given the USAAC designation P-66 and were assigned the serial numbers 
42-6832 thru 42-6975.  

Following the attack on Pearl Harbor on December 7, 1941, there was 
complete panic on the west coast of the USA.  The Japanese fleet was 
expected to show up off Santa Barbara at any moment.  In anticipation 
of a Japanese attack, some forty to fifty P-66s originally intended 
for China were hastily impressed into USAAC service and issued to the 
14th Pursuit Group for use in the emergency defense of southern 
California.  The pilots of the 14th Pursuit Group actually liked their 
P-66s, and they described the P-66 as being a very good aerobatic 
aircraft.  Test pilot Gil Clark thought that it was the best aircraft 
he had ever flown, being much better than the Curtiss P-36.  However, 
the cockpit layout was rather poor, and the aircraft was not 
sufficiently robust for a fighter.  In addition the P-66 had an 
disconcerting tendency to ground-loop, some 15 examples being lost to 
this sort of accident.  

Eventually, the US west coast was regarded as being sufficiently 
secure that the Vanguards were eventually released from USAAC service 
and allowed to be transferred to China.  The first shipment of P-66s 
left for China in February of 1942, the last aircraft being delivered 
by August.  They went first to Karachi (at that time in India) where 
they were assembled, tested, and ferried to China.  

The combat record of the Vanguard in China is rather undistinguished.  
The actual number of Vanguards which actually reached China is 
uncertain.  Several were lost during tests in India and others were 
lost while enroute to China.  Others remained unairworthy at Karachi.  
About twelve Vanguards were on station at Kunming with the 7th Fighter 
Squadron of the 23rd Fighter Group, but they saw little use.  Two 
Chinese squadrons based at An-Su saw combat action with the Vanguard 
from August 1943 onward.  Many Vanguards were destroyed on the ground 
during Japanese attacks.  The Vanguard had an unfortunate resemblance 
to the Japanese Nakajima Ki-43 *Oscar* and Nakajima Ki-44 *Tojo*, and 
several Vanguards were shot down by Chinese forces by mistake.  

Some Vanguards were placed in caves for storage at Chungking for use 
in the upcoming civil war against Mao's Communists.  Many were 
reported still in their crates as late as 1947.  I am uncertain if 
they actually saw any service during the civil war.  It is possible 
that there are some Vanguards in China STILL sitting in their crates 
in pristine condition.  Would be an astounding discovery if this were 
actually the case! 

Sources: 

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

  War Planes of the Second World War, Fighters, Volume 4, William Green, 
  Doubleday, 1964.  

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

Joe Baugher		AT&T Bell Laboratories   	
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