World's Largest Collection of Paper Models!
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The XB-35/YB-49 had some stability problems however, and were quite a radical design for the time. With no long tail to stabilize and help turn, the flying wing looked more like a boomerang than an aircraft. So, because of this and the usual dose of "politics," the powers that be went with the XB-36. The first flight was on August 8, 1946. The XB was developed with a nine-foot, two-inch single tire on each main gear, the largest aircraft tire ever produced. With this very heavy footprint, there were only three U.S. airfields with the 22 1/2 inch thick runways that were needed to support this heavy bomber. They were located at Carswell AFB, Texas; Eglin AFB, Florida; and Fairfield-Suisun (renamed Travis AFB), California. This single tire setup was soon discarded, and the twin-doubles developed. These proved much more effective. With more rubber on the pavement, a runway only 13 1/2 inches thick was required. This made 22 primary and 22 alternate fields available.
Modifications were made to the 22 "A" models, changing them into "B" models. Seventy-two more "B"s were produced, following its first flight on July 8, 1948. Changes were made in the R-4360 engines, upping the horsepower to 3,500 each. This gave a service ceiling of 42,000 feet and a top speed of 381 mph. Performance data now used was based on "combat weight"(expected weight over the target, not take-off weight). This computing method raised the "A"model to a speed of 345 mph and gave a service ceiling increase from 31,600 to 39,100 feet.
Then, more changes were made, and soon the "D"- model followed. It had more engine improvements and the addition of a single pod containing two General Electric J-47-GE-l9 engines under each wing. This gave a top speed of 439 mph with a service ceiling of 45,200 feet. Gross weight went to 357,500 lbs, cruising speed to 225, and it could carry a 10,000 lb load for 7,500 miles. Seventy one of the "B"s were modified to the "D" configuration. Landing speed remained a respectful 121 mph. The first operational B-36 aircraft was delivered to the 7th Bomb Wing 1BW) at Carswell AFB, Ft Worth, Texas, on June 26, 1948. When production ended in August, 1954, 385 of these powerful aircraft had been produced at a cost of $3.6 million each. The statistics on this plane are still very impressive. Wing span was 230 feet.
It was 162 feet long, had a tail that towered to 46 ft 10 in, the wing area
was 4,772 sq ft. The bomber had a fuel capacity of 32,910 gallons and engine
oil capacity of 1,200 gallons. A crew of from 12 to 15 was needed to man all
positions. Armament was eight remotely operated turrets with dual 20mm cannons
in each. Each cannon had 600 rounds of ammunition available except for the nose
position which had 400 rounds. All turrets, except the nose and tail turrets,
retracted into the aircraft. Later, the "J" model came into being. All non-essential and crew comfort items were removed along with other weight reducing measures. This decreased the basic weight, making the performance of the "J" model even more impressive. It had a gross weight of 410,000 lbs, cruise speed of 230 mph, and a max speed of 430 mph. Range was 8,300 statute miles with a service ceiling of 46,800 feet. On this model, all guns were removed except for two M-24, 20mm cannons in the tail. Although the new bomber was interesting and fun to fly, it had one rather naughty
problem that gave the maintenance men a real fit. It wouldn't hold its gas.
That's right...it was plagued with gas leaks. It didn't take long to become
evident that this was a problem that could not be fxed by on-base band-aids.
It would require something more drastic. So, after having them for less than
a year, B-36s were returned to the company to fix their leak problems. Here is other trivia data that really impressed all who qualified to fly this bird. The wing was more than seven feet thick at the root. A person could climb into the wing and work his way outboard of the center engine. The 19 ft square tipped props were geared to turn approximately one half engine speed to keep them sub-sonic, which gave that unforgettable throbbing. Each aircraft used 336 sparkplugs, a big portion of which required replacing after each mission. The engineer's station had an engine "analyzer" which was used periodically in flight to determine engine condition. Each engine carried its own oil supply of 150 gallons which was not enough in some cases. The aircraft had four bomb bays, which could be configured to carry up to 72,000 lbs of bombs.
The NB-36H was modified and used as an atomic reactor test bed. This aircraft
was operated by normal means, however, while testing was going on. This propulsion
idea did not prove out and was discarded, but it was the only plane to have
so served. Other aircraft were configured to carry fighter pl,anes. The McDonnell
XF-85 "Goblin," a flghter with folding wings, was developed to be
carried in the rear bomb bay but was never actually tested with the B-36. Tests
were also made with the RF-84F, carrying, deploying and recovering it using
a trapeze hook-up under the aircraft. They also tested the "TomTom"
wing-tip setup which was to carry an RF-84F on each wing tip. This was discarded
when it was found that the intense wing tip vortices made hook-up nearly impossible.
Plus, the fighter pilot was trapped in his aircraft for the entire flight. None
of these projects proved feasible, and all were abandoned.
There are four B-36s still intact and on display. The last one to fly is located at the Air Force Museum at Wright Patterson AFB, Ohio. The last one built, which is also the last to carry the SAC (Strategic Air Command) emblem is located at the General Dynamics plant in Ft Worth, Texas. A "J" model is on display at Offutt AFB, Nebraska, and a B-36H is on display at Castle AFB, California. From article by Col (Ret) Francis H Potter
These specifications were distributed quietly, and from four designs submitted the one offered by the Consolidated Aircraft Company was selected. This giant machine, the biggest that would go into service with the Army Air Force, was to have a wing span of 230 feet, a pressurized fuselage, six piston engines with pusher propellers behind the trailing edge, and a gross weight of 278,000 pounds. (The Flying Fortress of that period tipped the scales at 32,700 pounds. ) Two prototypes from the original blueprints were ordered, but
the building of them was assigned to the Convair factory at Forth Worth, which
at the time was turning out B-32 Dominators and B-24s. By 1943 it was apparent
that a strategic bomber of high performance would be necessary if Japan was
to be attacked from American bases-for the concept of island-hopping had not
come up---and production on the B-36 went into high The first basic model, the XV-36, came out of the shed on September 8, 1945, but did not actually fly until August 8, 1946, and by then the tail assembly had been changed from twin fins and rudders to a single fin and rudder, and a temporary armament system had been built in. The wings at their roots were six feet thick which allowed access to the Pratt & Whitney R-4360 radial engines during flight. The forward and rear compartments of the fuselage were connected by an eighty-foot tunnel along which a wheeled flatcar ran back and forth for the convenience of the crew. Then began a long, bitter period of interservice rivalry in which the B-36 became the chief pawn. The first production aircraft was flown on August 28, 1947, and with that twenty-two B-36A machines were delivered to the Strategic Air Command. They carried no armament, but were used mainly for pilot and crew training. Not until July 8, 1948, was a B-36B, complete with six retractable and remotely controlled turrets each mounting two 20-millimeter cannon in the fuselage with two more like weapons each in the nose and tail turrets, available. The engines were still Pratt & Whitney radials, and by now the weight had gone up to 328,000 pounds. Later models offered a much improved armament system, and the bays were modified to take two 42,000-pound bombs, and the new K-3A bombing-navigation system was installed as well as gun-laying radar. In some models the radials were replaced by four Allison J35 jets, and these were in turn replaced by General Electric J47 turbojets. With the new B-36 SAC had entered the giant, jet-propelled bomber sweepstakes.
Week after week saw broad modifications in the monster. Some were produced as strategic reconnaissance planes in which two of the bomb bays were turned into photo areas that mounted fourteen cameras. It was obvious no one knew what classification to aim for next. The RB-36D was revised to develop the parasite-fighter theory, then known as FICON (Fighter-Conveyor). In this a McDonnell XF-85 was slung under the fuselage, taken into the air and released at a specified time, or over a specified area, but this first experiment was soon abandoned, and the Republic GRF-84, an F-84 modified for release from a trapeze gear, was substituted. It seems that in this there was some hope of stretching the range of any contemporary fighter-an aircraft carrier of the air, so to speak. Final production versions of the B-36J, now weighing 410,000 pounds, were built in the spring of 1952, and by that time all piston-engined B-36s were retired. About eighty of the final model were assembled and shipped out to various squadrons. The 92nd Bomb Wing took them out to Guam. The I I th Bomb Wing had them in North Africa, and a few saw temporary service in Great Britain on training missions. By this time the B-36 had proved itself in many ways-that is as a peacetime bomber-and it had eluded United States interceptors in defense exercises since it could hide at extreme altitude, up to 45,000 feet, a ceiling made possible by its moderate wing-loading and high aspect ratio. There, of course, were questions whether this immunity would have lasted very long against the lightweight Russian MiG that first appeared in 1948, or the eventual improvement in Russian radar interception. In 1955 one B-36H was modified to become a test bed for a nuclear reactor, but in its first flights the reactor did not contribute to the propulsion. It was mounted to check the effect of radiation upon instruments, equipment, and airframe, and to develop certain shielding methods. What resulted from this study has not been divulged, but a B-36 that was to use nuclear power for primary propulsion was eventually abandoned.
General Dynamics (Convair) B-W Engines: B 36B. six 3.500 hp Pratt & Whitney R 4360-41 Wasp Major 28-cylinder four-row radials, B-361D, six R-4360 41 and four General Electric J47-1 single-shaft turbojets Dimensions; Weights: empty 1 150,000 Armament: normally, sixteen 20 20mm cannons in eight remotely controlled turrets, in nose and tail and in six retractable installations along the fuselage. Covered by slidng doors except when extended for use. Internal bomb load up to 84,000 lb History: first flight (XB-36) 8 August
19 To meet the possible need to continue World War II after the collapse of Britain the B-36 was planned to operate against Nazi-held Europe from bases in the United States or Canada. The specification called for a bomb load of 10,000 and delivered to a target 5.000 miles from its 5,000 ft runway. This was challenging enough, but the prototype programme was crippled by shortages due to its low priority and need to devote all effort to wartime production. Only at the end of World War II did the work gather momentum, and when the XB 36 flew it was the largest and most powerful air craft to take the air anywhere in the world. The Lin armed B-36A was used for training crews of the newly formed USAF Strategic Air Command (SAC), which inclosed The controversial monster as its central team of equipment Production aircraft had boge main goars pressunued front and rear crew compartments linked by an 80 ft trolley tunnel, comprehensive radar bombing and navigation system and automatically controlled defensive guns with five sighting stations. The RB-36 models had 14 cameras in place of two of the four weapon bays and a crew increased from 15 to 22. Technical problems were severe and until 1951 reliability was poor. In 1953 FICON trials were held to carry and launch F 84F manned reconnissance fighters Some of the final examples of the 385 B-36s built were stripped of most armament and used for very long range high altitude, reconnaissance carrying large quantities of ECM and other special sensing systems.
In addition, the requirement for cumbersome, specialized, and expensive handling equipment doomed weapons such as the MK17 to short service lives. These bombs could only be moved with straddle loaders or large cranes, and were not compatible with more standardized Air Force weapons handling equipment. They also could not be carried easily by the B-47 or B-52. The bomb casing was made of 3 1/2" thick aluminum with a lead and plastic liner to withstand internal explosive forces for as long as possible and to generate compressive plasma for the secondary. MK17 yield was on the order of 15 to 20 megatons, one of the most powerful nuclear weapons ever built by the U.S. The bomb could be carried effectively only by the B-36 aircraft; when the weapon was dropped, the delivery airplane usually leaped upwards several hundred feet due to the enormous weight loss. As an example of the handling difficulties associated with the MK17, in early 1955 a MK17 Mod1 training weapon was assembled at Manzano for carriage by a B-36 to Bossier Base, Louisiana because the latter site had no railhead capable of unloading the MK17 weapon case.
A "Broken Arrow" nuclear weapons accident involving a MK17 occurred on May 22, 1957 when a B-36 crewman inadvertently leaned against a release mechanism that dropped an unarmed MK17 (the "nuclear capsule" for the primary was not installed) through closed bomb bay doors and on to the desert in New Mexico near Kirtland Air Force Base. The heavy explosive in the bomb exploded on impact, killing an unfortunate cow and digging a crater 12 feet deep and 25 feet in diameter. Everyone on the plane knew when the bomb fell: the B-36 jumped up a thousand feet. The MK17s were retired from the stockpile between November 1956 and August 1957. It was withdrawn in favor of the MK 36 bomb, which was significantly smaller and lighter and featured a lower yield. A shift in U.S. targeting strategy from cities to military targets, along with a significant increase in the number of nuclear-capable SAC bombers, allowed the production and stockpiling of large numbers of relatively-low yield bombs in the place of a small number of high-yield bombs." *
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