Looks like the aircraft entered what is known as a deep stall; this occurs when the wings blank out the empennage, making the plane almost impossible to control.
This occurs with T -tail aircraft and the result is usually a flat spin.
The obvious question is why the aircraft went into a deep...
The company I worked for did maintenance of military aircraft.
Something went wrong during the night and it was quite a sight next morning to see a row of jet fighters covered in foam with only the vertical stabilisers protruding.
Andries
The British Bristol 188 supersonic research aircraft of the late 1950s had a stainless steel airframe to deal with aerodynamic heating.
Titanium was still in the future for aircraft.
Andries
Hi aldomoul,
As FEA way alluded to you must have a thorough grasp of basic mechanics of materials. Also read up on basic elasticity theory.
You must be able to do rough "sanity" checks on your results using hand calculations on a simplified representation of the part in question.
Another...
Thanks SAITAETGrad,
I fortunately have Cook's book and copies of Taig's notes; they really get down to the nitty-gritty of FE modeling.
(As far as FE text books go Cook et al is one of the best.)
On further reflection and the replies above I can now understand the use of a single CQUAD4 as a...
Good Day Colleagues,
I noticed that in two different aircraft company finite element manuals the light frames typically used in airliner fuselages
are represented by Nastran CRODS for the flanges of the stringer and a single QUAD4 element representing the web.
Surely a single QUAD4 will be too...
Hi All,
This thread is very interesting to me, a 77 year old museum piece. Yes, this surely the way to go. I suppose that you all have systems in place for archiving your calculations and keeping them up to date by configuration control (I'm from the aero industry where this is crucial)...
The idea of hundreds or even thousands of such aircraft (flying autos?)in the air, how on earth is this going to controlled? Road safety is bad enough, but this?
Andries
Good Day.
The Comet I fuselage skin was mainly from D.T.D.546B Aluminum alloy with thickness along the sides 0,036" and top and bottom 0,028".
Frame spacing was 21" and stringer spacing 5,5"(average).
Source: Aeronautical Research Council R & M No 3248: Behaviour of Skin Fatigue Cracks at the...
Gus, the fact that you are still employed while the company is going through a rough time means that they are satisfied with your contributions. I agree with TigerGuy that you should have a discussion with your boss, but keep things as positive as possible since he also has issues. All the best...
Hi Gibran,
It all depends: In what area are you intending to work, e.g. airframes or aerodynamics?
For airframe stress and structural analysis almost the industry standard finite element software is MSC Nastran, with Patran for model generation.
Then there are packages for non-linear analyses...
ESKOM was once a well-managed organization run by highly qualified engineers. Most appointments nowadays are political and many, if not most, of the qualified personnel were retrenched in the past two decades.
Andries
