Boeing's 400th production included crew ejection seats in a revised nose section, more powerful J47-GE-25 engines, and the General Electric A-5 fire control system (The engines had already been refitted in several B-47Bs). This configuration, first classified as an Air Force standard, was designated B-47E. A modified landing gear allowing heavier takeoff weight appeared on the 521st and subsequent B-47Es. This configuration was labeled B-47E-II. A far stronger landing gear was incorporated in the 862nd B-47 production. This last configuration of the B-47E model series was identified as the B-47E-IV The armament of all B-47Es was changed to two 20 mm cannons, and the 18 unit internal jet assisted take off system of early B-47Es was soon replaced by a jettisonable rack containing 33 units, each with a 1,000 pound thrust. Increasingly more efficient components equipped the B-47E and B-47E-II aircraft. Still, many later acquired the improved MA-7A bombing radar, AN/APS-54 warning radar, AN/APG-32 gun laying radar, and other highly sophisticated electronic devices first carried by the B-47E-IV (In later years, a number of B-47E-IV bombers featured the improved MD-4 fire-control system instead of the A-5). The under surfaces and lower portion of the fuselage of most B-47Es were painted a glossy white to reflect the heat from nuclear blasts (applied retroactively to some B-47Bs).
The Air Force accepted this plane in February 1953 and took delivery of 127 similar productions before mid year.
The B-47E first went to SAC's 303d Medium Bomb Wing, at DavisMonthan AFB. The 22d Wing at March AFB, California, upon transfer of its early B-47Bs to Air 1Yaining Command, would be next to receive the B-47E. The new planes fell far below the improved combat configuration (WIBAC Unit 731) endorsed by the Air Force in the same month. Yet, strides were being made. Besides the added safety of ejection seats, the B-47E from the start featured an approach chute to increase drag, a brake chute to decrease landing roll, arid an antiskid braking device. The discarded B-4 fire control system could at best spray fire in the general direction of an enemy, but the new A-5 could automatically detect pursuing aircraft, track them by means of radar, and correct the firing of its two 20 mm cannons.
The Air Force received its first B-47E IV in February 1955. The reinforced landing gear of this "heavyweight" production and subsequent ones permitted heavier take off weights, a significant achievement in the Air Force's quest for range extension (This had been a tricky undertaking from the start. Normally, range extension meant weight reduction. Yet, back in 1952, while some engineers tried to reduce the aircraft's weight, others needed to add equipment to improve mission performance. The solution at the time appeared to rest on better engines and lighter airframe materials, as proposed for the B-47C. When this did not succeed, SAC suggested modification of the B-47's tandem landing gear.). The B-47E IV had a take off weight of 230,000 pounds precisely 28,000 pounds more than previously permissible. Since the additional weight was largely allotted to fuel load, the B-47E IV had a combat radius of 2,050 nautical miles. This was almost twice the distance demonstrated 5 years before by the initial B-47s and about 300 nautical miles farther than earlier B-47Es, already equipped with somewhat stronger landing gears (The B-47E II, the first range extended B-47, reached the Air Force in August 1953, after being also brought up to the improved combat configuration that had been endorsed earlier in the year: After flight testing the stability of the modified plane, the Air Force flew it to find out if still higher gross weight take offs could be possible. This paved the way for the heavyweight B-47E IV.). The Air Force decided in March 1955 that in the next 4 years all active B-47s would be brought up to the heavyweight configuration. The modifications consisted of changing the aft landing gear and adding an emergency elevator boost system to ensure safe flights in spite of the increased weight. The forthcoming post production changes were priced at $9.2 million, but the Air Force deemed them well worth the cost.
There were also many minor variants of the B-47E:
- EB-47Es: Several B-47Es were fitted with additional electronic countermeasures equipment, primarily jammers. These EB-47Es, sometimes referred to as E-47Es, normally called for a crew of 5; otherwise, they were identical to the B 47E bombers which they were expected to accompany. The EB-47Es fulfilled many different tasks. Some of the aircraft carried a special electronic countermeasures equipment rack in the bomb bay. Known as Blue Cradle EB-47Es, they only required a 3 man crew.
- EB-47Ls: A number of B-47Es received communications relay equipment to allow them to serve as airborne relay stations for command post aircraft and ground communications systems. The EB-47Ls, requiring a 3 man crew, were replaced in the mid sixties by more modern aircraft.
- ETB-47E: After 1959 some B-47Es were used for training. As in the TB-47B's case, the converted ETB-47E featured a fourth crew seat for the instructor.
- QB-47E: In this configuration, all armament items and non essential equipment were removed from the B/RB-47E. Unmanned and radiocontrolled, the aircraft served as missile targets. These QB-47Es were considered as nonexpendable, because of their $1.9 million unit cost, and the guided missiles used against them were programmed to make near misses. A few 3 crew QB-47Es featured telemetric and scoring devices.
- WB-47E: Converted B-47Es featured nose mounted cameras that recorded cloud formations. WB-47Es also differed from the B 47Es by carrying air sampling and data recording equipment in place of nuclear weapons.
In total, 1,341 B-47Es were produced from 1953-1957. Boeing built 691, Douglas-264, and Lockheed-386.
The Air Force accepted 128 B-47Es in FY 53, 405 in FY 54, 408 in FY 55, 280 in FY 56, and 120 in FY 57.
The Flyaway Cost Per Production Aircraft was $1.9 million. Airframe, $1,293,420; engines (installed), $262,805; electronics, $53,733; ordnance, $6,298; armament, $253,411.
The cost per flying hour was $749.00.
The maintenance cost per flying hour was $361.00.
Delivery of the last B-47E coincided with the beginning of the aircraft's phaseout. Both occurred in 1957, shortly after the 93d Bomb Wing started exchanging its B-47s for more modern B-52s. The Air Force, nevertheless, expected the B-47 to be around for many years. The aircraft's accelerated retirement, as directed by President John F. Kennedy in March 1961, was delayed on 28 July by the onset of the Berlin crisis of 1961-1962. In the following years, B-47s were gradually committed to the Davis Monthan storage facility, but it took Fast Fly, a project initiated in October 1965, to hasten the demise of the elderly plane's. SAC's last 2 B-47s went to storage on 11 February 1966.
Spurred by the Suez crisis of 1956, SAC demonstrated its potential ability to launch a large striking force on short notice. Within a 2 week period in early December, more than 1,000 B-47s flew nonstop, simulated combat missions, averaging 8,000 miles each (a total of 8 million miles) over the American continent and Arctic regions. Commenting on the spectacular mass flights, General 'Twining, Air Force's Chief of Staff since 30 June 1953, said the operation showed that the ability to deliver nuclear bombs had clearly taken the profit out of war."
The B-47 made several record flights:
25 January 1957: A B-47 flew 4,700 miles from March AFB, California, to Hanscom Field, Massachusetts, in 3 hours and 47 minutes, averaging 710 miles per hour.
14 August 1957: A 321st Bomb Wing B-47 under the command of Brig. Gen. James V Edmundson, SAC Deputy of Operations, made a record nonstop flight from Andersen AFB, Guam, to Sidi Slimane Air Base, French Morocco, a distance of 11,450 miles in 22 hours and 50 minutes. The flight required 4 refuelings by KC 97 tankers.
30 November 1959: A B-47, assigned to the Wright Air Development Center, broke previous time and distance records by staying aloft 3 days, 8 hours and 36 minutes and covering 39,000 miles.
In 1954 The Air Force set aside 17 B-47Es, already equipped with the necessary alternators, to test the new MA-2 bombing system earmarked for the forthcoming B-52s. The decision's purpose was 2 fold. To begin with, it would speed up testing of the MA-2. Of equal importance, the relatively large number of aircraft involved would allow the training of a cadre of MA-2 technicians. And this, in turn, would provide skilled personnel for SAC's B-52 units much sooner than otherwise possible.
1968-on-As SAC's EB-47Es neared retirement, the United States Navy acquired 2 of the planes and Douglas began modifying them in mid 1968. In addition to their Blue Cradle equipment, these 2 EB-47Es received more passive and active electronic systems. Long range external wing tanks were replaced with a variety of pods filled with electronic countermeasures gear. More chaff dispensers were also added. The modified EB-47Es were redesignated SMS-2 and SMS-3 as they became part of the Navy's Surface Missile System, where they were expected to be used for almost 10 years to sharpen the electronic countermeasures skills of the Fleet. The 2 were due to be retired in the late seventies and to join some other 20 B-47s on display around the country.
Phaseout gradually took place between 1957-1966.
The final B-47E (Serial No. 53 6244) was delivered on 18 February to the 100th Bomb Wing at Pease AFB, New Hampshire. The famous "Bloody Hundreth" of World War II was the 29th and last SAC wing to be equipped with B-47s. One of these wings, the 93d, had converted to B-52s in 1955.
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