Hot answers tagged

79

The reason was to give the bombs the place close to the center of gravity. Wing sweep (for high cruise Mach numbers) in combination with a high aspect ratio of the wing (for low induced drag) made it impossible to place the landing gear in the wing, so it had to be integrated into the fuselage. The main landing gear normally needs to be close to the center ...


54

Adding to the excellent Peter's answer who explained why for this particular model the wheels are placed far behind the centre of gravity (CG), I would like to clarify why this makes impossible to rotate at take off. A standard aircraft takes off right after the rotation, increasing the angle of attack and the lift. Before and while performing the rotation ...


53

Testbed Aircraft Cameos As a young engineer in the 1960s at Pratt & Whitney Aircraft (now UTC’s Pratt & Whitney) in East Hartford, Connecticut, I was involved (along with many others) in the development of their 44,000 pound thrust (lbt) JT9D turbojet, which powered the first Boeing 747 jumbo jet aircraft[ Display footnote number: 2 ]. ...


38

Three reasons: The B-52 stayed useful by taking on "easier" roles as it aged. It actually started life as a high-performance penetrator, relying on speed and altitude to stay safe. Think Early Cold War, shortly after WWII. When ground-launched missiles improved, the B-52 was forced into flying low-altitude penetration underneath radars (a role for which it ...


28

It's worth digging into the details. The B-52H, which is the model in service today, was not built in the 1950s but the early 1960s (which, I admit, is not a significant difference). The key, however, lies in the upgrade programs that have happened constantly since the design first hit front lines. It's had airframe life extensions, avionics upgrades, and ...


27

The B-52 is nothing more than a massive bomb-truck, so it doesn't need a whole lot of improvements. If it ain't broke, don't fix it. It's not pretty, fast, stealthy, or smart. It's a vehicle to get a whole lot of bombs from point A to point Boom. Did you know the USA military still uses the M2 Browning machine gun from WWII? B-52s are great when you want ...


23

The B-52 was build in different versions (A-H) and the engines and their installation differ between these version1. The image in the question most likely shows the engine configuration of a B-52H. The following drawings suggest that this also changed the inlet design2. There seem to be different engine-designations depending on the application. For the B-...


22

The plane in the pictures is Boeing JB-52E -test plane. It used to test for instance the General Electric TF-39 engines for the C-5 Galaxy as it was under development


15

A lot of pictures of this intake make it quite hard to determine what is the exact geometry. But the one below is by far the best - thank you @ymb1. http://www.af.mil/News/Photos/igphoto/2001513002/ Before, it was hard to tell exactly what's happening. In some pictures, it looked like the inboard engine was slightly further forward of the outboard engine. ...


14

(Source) B-52D Stratofortress "Calamity Jane". It is a long-range, subsonic, strategic bomber operated by the US Air Force (not the Navy) since 1955. The aircraft you see here was amoung 170 B-52Ds manufactured by Boeing Airplane Company, and was equipped exclusively for long-range bombing missions. "Calamity Jane", as she is called, has ...


13

The B-52 is essentially nothing more than a cargo truck today. It's still useful in that role, although it's obsolete by most reasonable standards. It does help that the B-52 has its engines in nacelles, which simplified engine upgrades. To its cargo truck role, the engine performance matters more than anything. And as an old and simple plane, there's ...


11

There are two reasons and they date back to the early designs for the aircraft. Keep in mind the tail is different now than when it was originally designed. Boeing has originally planned for an all moving vertical stabilizer but engineers doubted its reliability and the systems to operate it simply would not fit in the tail at the time. More importantly the ...


8

There are a few reasons. The first is that the engines run more efficiently when the aircraft is moving. As the aircraft moves faster, it's easier for it to get more air into the engine, which helps it run more efficiently. The second reason is even simpler: like most aircraft a B-52 only rarely runs at full throttle. Most of the time that it's cruising, ...


7

Why does the B-52 outboard engine nacelle have a sharp change in shape? Not just the outboard, but all 8 engines on a B-52 have the same inlet design. The original engines had a smaller fan diameter and symmetrical round inlets. I suspect going to a larger fan diameter created flow problems which the engineers solved by modifying the inlets.


7

That looks like an optical illusion due to the angle to me. A photo on this site shows a more frontal view of the outboard engines, with just the equal centre division between the two engines appearing. Close-up underneath.


7

The angle of attack of the wings of a B-52 is positive. The leading edge of the wing is higher than the trailing edge. So when you see the aircraft takeoff it seems to not rotate, but when the fuselage is level, the wings are at a positive angle of attack. When the B-52 is in level flight, the nose is down, you can not see the nose from the cockpit and it is ...


7

Metal fatigue and fatigue corrosion are and have been a problem since the type's introduction. They always fatigue and corrode, they always undergo expensive repairs due to corrosion. DIEGME degradation of fuel tanks has been a particular culprit, and it has been reduced with new coatings. Bombers aren't pressurized, so the whole fuselage doesn't fatigue ...


6

Earlier B-52s did not carry all their fuel in the fuselage. They also carried their fuel in the wings using rubber bladder-type wing tanks. The new B52G “wet wing” was a weight savings measure which also increased the fuel capacity over the bladder-type in-wing tanks. The metal fatigue of the new wing was due to a poor structural design which was supposed ...


5

A four-engine configuration has been proposed at least two times but would require expensive modifications to the wings. A 2017 Flight global report, Rolls Royce offers BR725 for B-52 re-engine effort, said So far, the USAF has foregone plans to reconfigure the B-52s with four engines, which would have required expensive modifications to the wings, R-R ...


5

This inlet design was already used on the Convair B-36 D, which had twin turbojets added on the outer wing to give it a higher top speed when penetrating enemy airspace. During cruise, only the six piston engines would run and the jet engine inlets were plugged to reduce their aerodynamic drag. This plugged state is shown in the picture below (picture source)...


5

Several factors come into play: Having 8 of them, asymmetric thrust after an engine failure - which is often the dimensioning case for the size of the vertical stabilizer - is not much of a problem. Lateral control is primarily maintained by operation of spoilers. Apparently, an all movable vertical tail was to be used but didn't make it because of doubts ...


4

Boeing B-52G Stratofortress In the design of the B-52G, considerable attention was paid to reducing the structural weight. Different materials were used in the construction of the airframe, and the wing structure was extensively redesigned. The most visible difference was a vertical tail which was reduced in size. The height was reduced from 48 feet 3 ...


4

The decrease in fatigue is not a property that's automatically conferred to the plane by the introduction of wet wing - it's a product of smart design. Usually the decision to use a wet wing is made during the initial design of a plane, and the support structure of the wing is built accordingly, so that it can take the dynamic strains that occur upon ...


3

The military designation of the proposed JT4A is J75 (not to be confused with J57). It was proposed for the G-variant of the B-52, but it would have slowed down the production: The B-52G was proposed to extend the B-52's service life during delays in the B-58 Hustler program. At first, a radical redesign was envisioned with a completely new wing and Pratt &...


3

There were several proposals to do just that, none of them ever went beyond the proposal phase. Part of the reason is almost certainly the large stockpile of spare engines the USAF had (and maybe still has), taken in part from re-engined KC-135s. Part of the reason no doubt is also that there have been near constant plans to retire the B-52 "soon" and a ...


3

The B52 does "rotate" on takeoff just not to the degree of what seems normal for such a large jet. All airplanes must produce lift that is greater than the opposing force of gravity/its weight for it to leave the runway. When lift = weight/gravity the airplane is in a stable state, which means the rate of climb or descent will be constant. This means unless ...


3

Back in the day the BUF (correct acronym for "D" model) airframe usage was calculated using variable aspects of actual flight that were outside the assumptions that the engineers used to predict "ordinary" useful hours of the airframe. If for example the plane had a 20,000 hour useful life before major overhaul or permanent grounding, ...


2

I may have missed it, but it seems none of the answers addresses the main issue: why it does not rotate and climbs out in a nose-down attitude? All of this will be clearer if you remember that lift depends, mainly, on angle of attack and speed. The main way for any conventional airplane to take-off (and land) without rotating in pitch is by making the ...


2

The earlier variants were indeed easier to handle. The H-variant featured an independent spoiler panel for finer control to make it easier: In practice, the short fin combined with spoilers-only lateral control induced a tendency to Dutch-roll and low level handling was more sensitive than on earlier B-52s. Raising the spoilers also caused a slight pitch-up ...


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