Random facts about planes..
Discussion
So what totally random things do you know about planes that maybe the rest of us may find interesting?
I'll start off..
A commercial plane is generally only 3 routine inspections away from a catastrophic fatigue fracture failure.
(This is the time between the element fracture line becoming a visible thing and the time the element will fail due to the fracture growth size)
On many commercial planes there is a triangle symbol above some of the windows (internal).
This is to denote the leading edge of the wing and also the trailing edge of the wing.
I'll start off..
A commercial plane is generally only 3 routine inspections away from a catastrophic fatigue fracture failure.
(This is the time between the element fracture line becoming a visible thing and the time the element will fail due to the fracture growth size)
On many commercial planes there is a triangle symbol above some of the windows (internal).
This is to denote the leading edge of the wing and also the trailing edge of the wing.
Buzz84 said:
I was told that these triangle symbols were to tell the cabin crew which window has the best view of the front and back of the engines, So if there was a problem the crew knew exactly which window to go to if asked to by the captain. This can even be done on the sleigh by the cabin crew passing or stopping to "check" on the passengers there
Yes basically for the same thing.The leading edge of the wing is so that cabin crew can check for wing slat or engine problems.
The trailing edge of the wing for cabin crew to check for flap/aileron issues or engine problems.
But essentially the cabin crew can quickly note the location of the wing in order to quickly assess views of any issues relating to the wing or engines.
The start procedure for a jet engine is not just pressing a button and off you go...
Step 1 - use an external compressed air source to start spinning the blades/internal compression system. (or use plane's own auxiliary power unit if available)
Step 2 - wait until a specific minimum revolution velocity has been reached.
Step 3 - then introduce fuel and wait for ignition
Step 4 - then allow the engine to become self powered
Step 5 - allow the engine to stabalize.
Step 6 - air pressure from engine one can then be channeled to engine two for its own start up procedure.
Step 1 - use an external compressed air source to start spinning the blades/internal compression system. (or use plane's own auxiliary power unit if available)
Step 2 - wait until a specific minimum revolution velocity has been reached.
Step 3 - then introduce fuel and wait for ignition
Step 4 - then allow the engine to become self powered
Step 5 - allow the engine to stabalize.
Step 6 - air pressure from engine one can then be channeled to engine two for its own start up procedure.
CanAm said:
Without any power any aircraft can glide for some distance.
"Some distance" being likely to be a whole lot further for a Lockheed U2 than a Cessna 172.
A typical sparrow bird has a lift to drag ratio of 4:1, whereas an albatross is much more efficient with 20:1."Some distance" being likely to be a whole lot further for a Lockheed U2 than a Cessna 172.
A modern glider which demonstrates the most efficient of wing profiles can have a lift to drag ratio of 60:1.
eccles said:
To be fair, a Tornado could do a pretty similar thing back in the 80's. Once the driver got off the ground you press play on the tape and it would fly via way points a set heights and drop the bombs where programmed and then return to base for the driver to land it.
I remember asking a Tornado pilot what the tape deck was for, when I had a look around the cockpit on one of my first flying lessons with the ATC many years ago. (I wasn't flying the Tornado by the way, I was in a rattly washing machine otherwise known as a Chipmunk).He said it was for simply listening to mission instructions and target information etc. Or if they chose to, to listen to a bit of rock and roll !
I guess I was asking a question that required a classified answer back then
CanAm said:
e have the Cessna at 9:1, the Gimli Glider Boeing 767 at 12:1 and I was very disappointed to find the U2, despite its very high aspect ratio wings, only has a glide ratio of 23:1; the rather stubby winged Messerschmitt Me163 (aspect ratio of less than 5:1) had a glide ratio of about 20:1, though to be fair gliding was an important part of its design brief.
So the U2's glide ratio is only 2.5 times better than the not very aerodynamic Cessna; but when you start your glide at 70,000 feet you have a definite advantage. One managed 300 miles after an engine failure!
Yes it is surprising that the U2 does have a low ratio in comparison to other wings of similar looking, but when you take in to account that the U2 is powered and also will have requirements for a specified performance envelope that is to work at a range of altitudes. temperatures, pressures and angles of attack, then maybe what they produced was more by design intent than lack of aerofoil knowledge for lift performance?So the U2's glide ratio is only 2.5 times better than the not very aerodynamic Cessna; but when you start your glide at 70,000 feet you have a definite advantage. One managed 300 miles after an engine failure!
I'm guessing they could have gone for a more 'lifty' profile but would then have encountered more drag, which then would have meant more fuel, less range etc. etc.
The typical problem (or benefit) you run in to called 'circle of returns' within aerodynamics when one factor is altered, which then has knock on affects to all other factors within the design.
Similarly, if they had opted for more aspect ratio on the wing, it would have resulted in lower roll rate, more drag, more wing flex (if not wing flex then more weight for strengtheners) etc. etc.
Ginetta G15 Girl said:
The major component of Drag on any wing is Induced Drag (also known as Lift Dependant Drag). This arises primarily from the formation of the wing tip vortices - basically the air from the higher pressure region below the wing tries to move into the lower pressure region above the wing by climbing over the wingtip. In so doing it forms a vortex which produces drag (it takes energy to form and maintain the vortex).
There are a number of ways of reducing these vortices (or delaying their onset) such as eliptical wings (eg Spitfire), wingtip tanks (eg Jet Provost), winglets (such as fitted to modern airliners) or, more commonly, the High Aspect Ratio Wing (ie a high length to chord ratio - long and thin) such as on the U2.
Given that the U2 was designed to operate at very high altitude in a region close to 'Coffin Corner' (ie where the Critical Mach Number and Stall Speed are close together), then a means of reducing drag such as a High Aspect Ratio Wing makes a lot of sense.
Thanks Ginetta Girl. There are a number of ways of reducing these vortices (or delaying their onset) such as eliptical wings (eg Spitfire), wingtip tanks (eg Jet Provost), winglets (such as fitted to modern airliners) or, more commonly, the High Aspect Ratio Wing (ie a high length to chord ratio - long and thin) such as on the U2.
Given that the U2 was designed to operate at very high altitude in a region close to 'Coffin Corner' (ie where the Critical Mach Number and Stall Speed are close together), then a means of reducing drag such as a High Aspect Ratio Wing makes a lot of sense.
Edited by Ginetta G15 Girl on Wednesday 19th April 13:06
I remember doing a small piece on wing tip vortex drag on my Degree course many years ago.
I was looking at the effects of vortex drag on the yaw stability and control of the rudder for a glider concept - looking at how much rudder adjustments in size and angle would be needed if the glider were to reach certain dive speeds etc.
thebraketester said:
100% true.
Same as magnets. No one know how they work either.
Magnets work due to special relativity.Same as magnets. No one know how they work either.
https://www.youtube.com/watch?v=1TKSfAkWWN0
Again, nice theory, but then outside of the world of maths, every reason for why something works or not is a "theory".
So if you accept the theory then one does not have to deal with black & white 'fact'
You only have to worry about a superseding theory that matches prediction and measurement more accurately.
Ian Lancs said:
Ayahuasca said:
There are, at any given moment, over 1,000 B737s in the air.
And here they are (if this link works) https://www.flightradar24.com/11.29,-46.04/2Even though flightradar is only providing a partial picture, it doesn't display all aircraft currently flying, there are many regions over land and water that flight radar does not receive data from.
https://www.youtube.com/watch?v=WAud8KpFyvM
Crazy just how many and much need people to move about these days.
HoHoHo said:
Some googling suggests............
7. About 1 in 5 people have some of fear flying, or “aviophobia.”
I am one of those.7. About 1 in 5 people have some of fear flying, or “aviophobia.”
Even though in my younger days I was heading in to the RAF on the initial officer training program looking to become a fast jet pilot, and even though I studied aeronautical engineering at Loughborough uni , I still have a fear on take off and landing in passenger planes when my safety is in the hands of other people.
I remember feeling totally fine when I went up in the shakey washing machine that was a Chipmunk and also fine in the slightly better environment of the Bulldog (when in both, the options available when things go wrong is to open the cockpit, climb on to the wing and jump off hoping that the parachute attached to your derriere will open in time before you meet the ground ! )
Its an irrational fear, as I am well aware of how planes are put together, the factor of safety installed, the back up systems, etc. etc., but with that I have knowledge of how easily things can go wrong and how reliant one is on the system as a whole simply 'working', but as with a lot of things the sense of 'fear' plays more weight than the sense of 'rationale'.
Edited by Atomic12C on Thursday 27th April 16:22
The coefficient of lift for any aerofoil is a dimensionless number - it basically captures a shape within the lift equation.
The Wright brothers famous airplane did not adopt ailerons in order to cause a roll movement on their plane, instead they had an arrangement of wires which were pulled to deform the whole wing shape which would cause more lift on on side of the plane than the other.
Interestingly enough there is an amount of new research in to adopting this old concept to control aircraft roll via the use of new flexible and composite materials and modern avionics, with the end aim to give a reduction in weight and more effective/efficient control over the aircraft.
The Wright brothers famous airplane did not adopt ailerons in order to cause a roll movement on their plane, instead they had an arrangement of wires which were pulled to deform the whole wing shape which would cause more lift on on side of the plane than the other.
Interestingly enough there is an amount of new research in to adopting this old concept to control aircraft roll via the use of new flexible and composite materials and modern avionics, with the end aim to give a reduction in weight and more effective/efficient control over the aircraft.
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