New answers tagged turbofan
5
Two worlds
There are two elements constraining propeller use:
The thrust we can get from a free propeller is lower than from a ducted fan at the same airspeed.
Propeller efficiency quickly decreases with Mach number.
Propeller performance vs speed. Source
For these reasons fans are the natural choice for large and fast aircraft, and propellers for slower ...
0
I think it's a camera distortion caused by vibrations: an effect you can see when some harmonics are prox to shutter frequency and can cause image distortion. In fact at 1:04 you have the same effect during pushback with engine off yet.
2
To generate thrust, engines need fuel and air: a spark will ignite fuel (by getting heat, above the ignition point), which burn with the oxygen in the air.
On this (and other incidents), together with air, also rain (and hail or snow) in the engine, so the spark is not enough to ignite the fuel, and so the engines stop working. So, this is the important ...
4
The answer is unequivocally no. Not only is it not possible, but what would be the point of designing them to do that?
The only thing that expands in the turbo jet engine are the turbine blades themselves, but the amount they expand is infinitesimally small.
1
As the aircraft starts its takeoff roll, you can see the window frame flex in and out. One possibility is that as the engine spools up, it's creating a low pressure region around the entire front cowling, causing the fuselage to bulge out slightly. Rather than the engine distorting or seeming to turn in, it is the side of the fuselage flexing.
2
I don't see any dilation or change to cowling size except I could "see" dilation is in the bottom left of the window. The edge of the engine anti-ice and a line in the window changed distance. See my red rectangles in the attached photo.
I believe this is an optical illusion. I suspect the cabin pressure increased as the engine spooled up and provided ...
3
If you line up the two pictures using the tire tracks on the ground and the wing, it is clear the camera position has changed. Look at the outboard hinge for the flaps (with the circular dot) relative to the marks on the ground, for example. Also look at the mark on the ground near the inboard hinge, which is close to the wing in the first picture but half ...
45
Now that's an interesting phenomenon! I do not believe that this is a case of an illusion of any sort, or the engine dilating. What the video probably shows, is the engine slightly turning towards the window as takeoff thrust is being applied.
Engine mounts are not 100% rigid, this can easily be observed on pretty much any passenger flight if you can see ...
3
it depends on what you call 'high-bypass'. The RB.211 engine was tested in a tail mount on a VC-10:
For tail-mounted high-bypass engines, the engine mount gets long, which means it gets heavy.
Tail- and bodymounted engines in general have drawbacks that also apply to high-bypass engines:
the high position means maintenance access requires special ...
2
Unfortunately the short and simple answer is money. They weren't prepared to spend the money on a costly redesign of the already proven 737NG fuselage.
The best in depth explanation I've seen of the whole issue with the MAX is: "How the Boeing 737 MAX disaster looks to a software developer".
-1
The turbojet engine develops most the thrust in the exhaust nozzle.
The turbofan engine develops most of the thrust in the fan.
No engine develops all thrust in the exhaust or in the fan. There is a balance between the two components
Exception makes the turbo shaft where the turbine absorbs all power from exhaust gas to drive the shaft. Both airplane and ...
2
The technical answers above are fairly good, but probably the biggest answer is that Boeing corporate out in Chicago was simply too miserly to invest in a clean sheet airplane (which it could have EASILY done) and demanded that Boeing Commercial Airplane develop this new medium range airliner on a limited budget within a limited time span. The 737 MAX ...
1
Boeing's main problem was time to market - they were in a tremendous hurry to compete with the latest Airbus. Re-engineering the undercarriage would have been more complex and taken a lot longer than adjusting the design of the new engine pylons.
Perhaps ironically, the latest Max 10 has had the time to develop an extending undercarriage, giving it 9 inches ...
6
Because lengthening the main gear struts constitutes an almost complete structural re-design of the main wing structure, with dramatic consequences on cost, lead time, re-certification, weight increase etc.
The main landing gear of most swept back winged aeroplanes retract behind the rear spars, in the kinked section close to the fuselage. Picture above is ...
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