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2

Borane fuels are not practical for a multiple-use aircraft, primarily because there are no naturally occurring sources they could be easily derived from. This rules them out commercially, and gives a military disadvantage of being unable to utilize local supply chains. Note that the XB-70's borane fuel was to be carried in addition to kerosene, for one ...


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.


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 ...


14

The main place engine manufacturers will focus on minimizing damage is with the large fan at the front of a turbofan engine. FAA Advisory Circular 33-5 discusses the regulations that cover this. The manufacturer must show that the worst case blade rotating at the highest RPM can successfully be contained. Only 15 seconds after the event is the operator ...


9

A jet engine may not contain a severe explosion (for whatever reason) but there are various mandated things that are put in place to help protect the airframe. The engines are generally mounted such that they shear off cleanly and away from the airframe. There are a few AC's like this one and this one that discuss how to deal with and comply with various ...


6

Cowlings can be designed to contain fan failures but if the core comes apart you have some pretty high velocity shrapnel coming out that nothing short of quarter inch armour plate will stop. The main design feature you typically see to mitigate burst risk is the placement of cable runs and hydraulic runs, where there are redundant runs, spaced apart in the ...


25

The most (kinetic) energy is in the fan and turbine blades and disc. The engine is enclosed in a containment chamber whose purpose it is to protect the rest of the airplane from shrapnel in case of a fan disc or fan blade failure. Here's a video of a test where a fan blade failure is simulated: As you can see, the fan blade ...


1

Centrifugal compressors are limited by the size and sharp angle of the diffuser duct that has to straighten out the outward flowing air flow from the impeller compressor and reroute it back to the combustion chambers. This restricts the amount of air that can flow through this engine. Axial flow engines are straight through design and don't have this ...


51

No, the helicopters are standard production versions. The Eurocopter AS350 is a common model used for these operations. In 2005, Didier Delsalle landed a Eurocopter AS350 B3 on the summit of Mt. Everest at 29,029 feet (8848m) (twice). The only changes he made to the standard version were removing a few things like extra seats to reduce the weight, and of ...


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