| The B-36 was an immense aircraft in every dimension | | | | the Vietnam War. |
| and one of the last of the piston driven bombers. | | | | The B-36D had six 3500 Pratt and Whitney Wasp |
| Designed as a long distance heavy bomber capable | | | | Major radial engines mounted facing rearwards on the |
| of carrying a huge bomb load or the nuclear bombs | | | | trailing edges of the wings, plus four 5200 lb thrust |
| of the period, it went through numerous re-designs | | | | GE J47 turbo jets. It had a maximum speed of 439 |
| and modifications. The first B-36A was built in early | | | | mph at 32,120 feet with a cruising speed of 225 mph |
| 1947 and flew for the first time on August 28, 1947. | | | | and a range of 7500 miles. Its service ceiling was |
| The models B and C soon followed and were found | | | | 45,200 feet. To clear a 50 ft obstacle on take-off, it |
| wanting for one reason or another, mostly because | | | | needed 5685-ft runway. Empty it weighed 161,370 |
| the Air Force and the Government's Department of | | | | lbs., combat weight of 250,000 lbs., with an absolute |
| Defense could not arrive at a long-term agreement | | | | maximum lift off weight of 370,000 lbs. |
| about what they wanted. Some wanted the B-36 to | | | | The B-36D's wingspan was 230 feet, its length 162 |
| fill the gap before the B-52's would be delivered; | | | | feet 1 inches, with a height of 46 feet 8 inches and a |
| others thought it was not needed at all and still | | | | wing area of 4772 square feet. For armament it |
| others changed their minds every month or so. | | | | carried two 20-mm cannon in each of six retractable, |
| The early versions of the B-36 had been criticized for | | | | remotely controlled fuselage turrets, plus a tail turret |
| insufficient maximum speed and for a too-long | | | | and a nose mounting. |
| takeoff run. On October 5, 1948, Convair proposed | | | | The B-36D had a crew of 15: commander, two pilots, |
| that these problems could be addressed by fitting | | | | two engineers, navigator, bombardier, two radio |
| two pairs of turbojets in pods underneath the outer | | | | operators and an observer forward (the first radio |
| wings. These turbojets would be used for takeoff | | | | operator handled ECM while the second radio |
| and for short bursts of speed during the bombing run | | | | operator, the copilot and the observer operated the |
| and would have only a minimal effect on the range. | | | | three forward turrets. The rear compartment |
| These changes resulted in the B-36D version. | | | | accommodated five gunners, including one for the |
| The B-36D featured two pairs of General Electric | | | | radar controlling the tail turret. |
| J47-GE-19 turbojets in pods underneath the outer | | | | On January 16, 1951, 6 B-36Ds were flown from |
| wings to assist the six R-4360-41 engines. These | | | | Carswell AFB to the United Kingdom, landing at RAF |
| pods were quite similar to those fitted underneath | | | | Lakenheath after having staged through Limestone |
| the inner wing of the Boeing B-47 Stratojet. The jet | | | | AFB in Maine. The flight returned to Carswell on |
| engines increased the maximum speed to 435 mph | | | | January 20. This marked the first time that B-36s had |
| and the ceiling to more than 45,000 feet. In addition, | | | | flown outside US territory. A flight to French Morocco |
| they reduced the takeoff run by almost 2000 feet. | | | | was made on December 3, when 6 B-36s of the 11th |
| The first true production B-36D flew on July 11, 1949. | | | | Bombardment Wing landed at Sidi Slimane, having |
| The first B-36Ds were accepted by the USAF in | | | | flown non-stop from Carswell AFB. |
| August of 1950 and were initially sent to Eglin AFB | | | | Gradually, most of the problems with the B-36 were |
| for testing. By June of 1951 26 B-36Ds had been | | | | identified and corrected. An early major B-36 problem |
| delivered. The last B-36D was accepted in August of | | | | was leakage in the fuel system. In addition, the |
| 1951. A total of 81 B-36Ds were delivered to the | | | | electrical system was unreliable and caused frequent |
| USAF, 22 built as B-36Ds from the start and 59 | | | | fires. Improved containers and better sealants |
| others were converted from B-36Bs. | | | | reduced fuel tank leakages. Changes in the electrical |
| The model D was fitted with snap-action split | | | | system reduced fire hazards during ground refuelling |
| bomb-bay doors as opposed to the sliding type | | | | operations. Landing gear and bulkhead failures were |
| doors fitted to the preceding B-36As and Bs. These | | | | almost totally eliminated. |
| doors could open and close in only two seconds and | | | | However, even by October of 1951, the B-36D's |
| were extremely hazardous to ground crew. The | | | | defensive armament system was still performing |
| maximum bomb load was 86,000 pounds, consisting | | | | poorly. In April of 1952, the Air Force ordered a |
| of two 43,000-pound bombs. Smaller alternative loads | | | | series of gunnery missions to see if the cause of the |
| consisted of three 22,000 pound bombs, four | | | | failures could be determined. This test was completed |
| 12,000-pound bombs, 12 4000-lb bombs, 28 2000-lb | | | | in July. The K radar system was found difficult to |
| bombs, or 132 500-lb bombs. Such loads were not | | | | operate and maintain and the training for the gunners |
| equalled until the "Big Belly" B-52D modifications during | | | | was found to be inadequate. |