Vultee BT 13 Valiant

par Jeannot Mar 29 Déc 2009, 17:05

History:
With retractable landing gear and a powerful engine, the Vultee V-54 basic combat trainer was too lavish for the cash-strapped United States Army Air Corps of 1938. So Vultee redesigned the aircraft and made it less complicated. The first order for 300 new BT-13 Valiants was placed in September of 1939, and it would become the most widely-used American training aircraft of World War Two.

The Vultee BT-13 had a continuous canopy with its crew of two sitting in tandem behind dual controls. It was also equipped with blind flying instruments to teach new pilots the basics of flying at night or in foul weather. BT-13 students soon gave the airplane a nickname which described its most memorable characteristic: Vultee Vibrator.

The only major variant of the BT-13 was the BT-13B, which featured a revised electrical system. Because of the speed with which the BT-13s were built, there was soon a shortage of Pratt & Whitney Wasp Junior engines. To overcome the shortage and maintain production levels, the BT-15, using a Wright Whirlwind engine, was then introduced. Two thousand BT-13s and BT-13Bs were transferred to the US Navy, where they were designated the SNV-1 and SNV-2B.

When production ceased in 1944, 11,537 Valiants had been produced. The Valiant was retired at the end of the war, but over 100 of these aircraft are still registered in the United States today, although it is believed that less than half are actively airworthy.

Nicknames: The Vultee Vibrator, The Bee Tee

par Jeannot Mar 29 Déc 2009, 17:07

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par Jeannot Mar 29 Déc 2009, 17:11

Design and development

The [Vous devez être inscrit et connecté pour voir ce lien] BT-13 was the basic trainer flown by most American pilots during World War II. It was the second phase of the three phase training program for pilots. After primary training, the student pilot moved to the more complex Vultee for basic flight training. The BT-13 had a more powerful engine and was faster and heavier than the primary trainer. It required the student pilot to use two way radio communications with the ground and to operate landing flaps and a two-position variable pitch propeller. It did not, however, have retractable landing gear or a hydraulic system. The large flaps are operated by a crank-and-cable system. Its pilots nicknamed it the "Vultee Vibrator."

Due to the demand for this aircraft, and others which used the same [Vous devez être inscrit et connecté pour voir ce lien] engine, some were equipped with [Vous devez être inscrit et connecté pour voir ce lien] powerplants of similar design and power built in 1941-42. The Wright-equipped aircraft were designated BT-15.
The Navy adopted the P&W powered aircraft as their main basic trainer, designating it the SNV.

Today, some "BT's" (collectively, BT-13s, BT-15s and SNVs) are still flying, though in very limited numbers (and none in military or government service). After WWII, virtually all were sold as surplus for a few hundred dollars each. Many were purchased just to obtain their engines, which were mounted on surplus biplanes (such as [Vous devez être inscrit et connecté pour voir ce lien]) to replace their less powerful engines for use as cropdusters. The BT airframes were then scrapped. The BT-13 production run outnumbered all other Basic Trainer (BT) types produced.

It was back in 1938 that Vultee Aircraft's chief designer, Richard Palmer, began the design of a fighter. At this time the USAAC issued a requirement and design contest for an advanced trainer for which substantial orders had been promised to the victor. Palmer began to adapt his design concept from a fighter to that of an advanced trainer and the result of this was the V-51 prototype.

The aircraft made its maiden flight sometime during March 1939 as a [Vous devez être inscrit et connecté pour voir ce lien] low-wing monoplane of all-metal construction. Despite the use of metal throughout the design the control surfaces remained fabric-covered. The prototype was powered by a [Vous devez être inscrit et connecté pour voir ce lien]-S3H1-G Wasp radial rated at 600 hp (447 kW) driving a two-blade variable pitch metal propeller. Other features included an enclosed cockpit for the crew of two, integral fuel tanks in the wings, and a hydraulic system for the operation of the flaps and retractable main landing gear.

The V-51 was entered into the USAAC competition as the BC-51 during May 1939. The USAAC instead chose the [Vous devez être inscrit et connecté pour voir ce lien], but purchased the BC-51 prototype anyway, designating it the BC-3. Despite the disappointment, Palmer was not finished yet. He continued to refine the design of the VF-51 into the VF-54 in an attempt to meet the expectation of an export market for just such a trainer. The VF-54 used the same basic airframe as the VF-51, but was fitted with a lower powered engine. No export sales were made.
From this design, evolved the VF-54A. Instead of retractable gear, it had fixed gear very nicely faired and a revised power plant of a [Vous devez être inscrit et connecté pour voir ce lien]-T3B Wasp Jr. radial rated at 450 hp (335.5 kW) and the Vultee BT-13 Valiant was born.

The USAAC was made aware of the improvements made to the aircraft and in August 1939 the type was ordered as the BT-13. The initial order was for 300 aircraft with a [Vous devez être inscrit et connecté pour voir ce lien]-25 radial and the first of these was accepted by the USAAC in June 1940.

The BT-13A was produced to the extent of 7,037 aircraft and differed only in the use of a [Vous devez être inscrit et connecté pour voir ce lien]-AN-1 radial engine and lack of landing gear fairings. There were 1,125 BT-13B's produced and differed from the A model in having a 24-volt, rather than the original 12-volt electrical system.

The next variant was actually designated BT-15 because Pratt & Whitney found it impossible to keep up production of the R-985 engine. Instead a [Vous devez être inscrit et connecté pour voir ce lien]-11 radial was substituted into the 1,263 aircraft produced.

The US Navy began to show an interest in the aircraft as well and ordered 1,150 BT-13A models as the SNV-1. In addition, the Navy ordered some 650 aircraft designated as SNV-2 roughly equivalent to the BT-13B.

Once in service, the aircraft quickly got its nickname of "Vibrator" because it had a tendency to shake quite violently as it approached its stall speed.

The BT-13 served its intended purpose well. It and its successors were unforgiving aircraft to fly, but were also extremely agile. Thus the BT-13 made a good aircraft to help transition many hundreds of pilots toward their advance trainers and fighters yet to be mastered.

par Jeannot Mar 29 Déc 2009, 17:13

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par Jeannot Mar 29 Déc 2009, 17:16

Variants

BC-3 Vultee Model V.51 with retractable landing gear and a 600hp P&W [Vous devez être inscrit et connecté pour voir ce lien]-45, one built, not developed.
BT-13 Vultee Model V.54 with fixed undercarriage and a 450hp P&W [Vous devez être inscrit et connecté pour voir ce lien]-25 engine, 300 built.
BT-13A As BT-13 but fitted with a 450hp R-985-AN-1 engine and minor changes, 6407 built, survivors re-designated T-13A in 1948.
BT-13B As BT-13A but with a 24-volt electrical system, 1125 built.
BT-15 As BT-15 with a 450hp Wright [Vous devez être inscrit et connecté pour voir ce lien]-11 engine, 1693 built.
BT-16 One BT-13 was re-built in 1942 by Vidal with an all-plastic fuselage as the XBT-16.
SNV-1 BT-13As for the United States Navy, 1350 transferred from USAAF.
SNV-2 BT-13Bs for the United States Navy, 650 transferred from USAAF.
T-13A Surviving BT-13As were re-designated in 1948, due to dual allocation of T-13 with the [Vous devez être inscrit et connecté pour voir ce lien] in practice they were still known as the BT-13 to avoid confusion.

par Jeannot Mar 29 Déc 2009, 17:23

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par Jeannot Mar 29 Déc 2009, 17:26

et une petite vidéo : [Vous devez être inscrit et connecté pour voir ce lien]

par KUNDT Mar 29 Déc 2009, 18:37

Un Vultee BT 13 aux couleurs françaises !

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par KUNDT Mar 29 Déc 2009, 18:40

La légende :

Vultee BT 13 B Valiant - Ecole de Chasse - BA 708 Meknès (Maroc) - 1947.

----------------------------------------------on en apprend tous les jours !

Un dessin 3 vues :

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par JETHRO Mar 19 Oct 2010, 10:35

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par JETHRO Mar 19 Oct 2010, 10:36