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quiz question. do not google.
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By *4bim OP Man
over a year ago
Farnborough Hampshire |
after PW asked why people dont start new threads i will ask a question for you all to guess the answer.
its just for fun so please do not google or youtube as my video on there will reveal the answer. and yes i am a qualified pilot who has done this in a simulator for an emergency procedure.
i also work on development of m/softs flight simulator.
Question.
you are onboard a boeing 747-8 series.
all four engines have been lost and the plane is in a glide.
Attitude is at 43,000.
you are over the ocean.
how long do you have before you ditch into the sea?
how many miles will you glide.
closest person wins and if your into gaming and have steam i will contact you.
good luck |
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By *4bim OP Man
over a year ago
Farnborough Hampshire |
"You won't actually glide as a 747 with all for engines out will go into a dive and the friction will tear the wings off at that altitude and speed"
all fixed wing passenger aircraft have to be able to glide with complete engine failure or they are not allowed to go into service |
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Hmm.
I have no concept of what speed a glide would be at. Nor how much outside effects would alter the results. And honestly I've never really thought about the maths of aviation.
So, stab in the dark at 3 minutes and 7 miles. |
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By (user no longer on site)
over a year ago
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Without knowing windspeed, wind direction, weight and (crucially) current aircraft speed, its hard to answer...
But assuming absence of a massive head or tailwind, and assuming a regular cruise speed (c. 550mph), I'd guesstimate about 140 miles
(As an avgeek and physicist, this is my kinda quiz question!!) |
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"after PW asked why people dont start new threads i will ask a question for you all to guess the answer.
its just for fun so please do not google or youtube as my video on there will reveal the answer. and yes i am a qualified pilot who has done this in a simulator for an emergency procedure.
i also work on development of m/softs flight simulator.
Question.
you are onboard a boeing 747-8 series.
all four engines have been lost and the plane is in a glide.
Attitude is at 43,000.
you are over the ocean.
how long do you have before you ditch into the sea?
how many miles will you glide.
closest person wins and if your into gaming and have steam i will contact you.
good luck"
I expect the exact figure would be influenced by environmental factors. But at an initial cruising speed of 500mph let’s assume you lose 1,000 feet per minute for the first 23,000; 1,500 feet per minute for the next 10,000; 2,000 feet per minute for the final 10,000.
I’ll say 34 minutes gliding time.
Distance covered - you’ll lose speed at a faster rate the slower you go and the lower you are, so I’m going to guess at 100 miles. |
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By (user no longer on site)
over a year ago
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I guess the descend rate would kind of depend on how heavy the 747 is? With passengers or without??
With passengers it's going to descend quicker??
I'm guessing there is calculation of some description; 43000 ÷ however many knots to get the travel distance
I could be and probably way off though.
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By (user no longer on site)
over a year ago
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"
The galangung gliding club 
Also the Gimli Glider and Airtransat into the Azores, all frequently used. But still don't know lol"
If its a rapid dismantling of the plane it's a much shorter distance and a much quicker decent
I know that from experience |
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Overall system Force balance.
F = Fgravity - F(lift)
Lift is a function of velocity and aerodynamic properties of the plane. Assuming the pilot can hold the plane preventing a dive. Couldn't tell you how possible that is, not a pilot. And assuming fluctuations in velocity do not significantly effect lift. (This is an estimation afterall). I imagine in reality the skill of the pilot here is to maintain a glide speed by altering pitch etc reflexively? That's too complex a variable to model effectively as it is a human interaction.
That force balance will give a resultant downward acceleration and starting height. Convert altitude into SI units you can work out how long it will take to contact with the sea. Equations of motion.
Then you can use equations of motion to determine distance travelled as you know how long the glide is and the glide speed.
Not doing the math. Just off the top of my head haven't done Physics in years. I reckon it will give a decent estimate?
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By *abioMan
over a year ago
Newcastle and Gateshead |
"after PW asked why people dont start new threads i will ask a question for you all to guess the answer.
its just for fun so please do not google or youtube as my video on there will reveal the answer. and yes i am a qualified pilot who has done this in a simulator for an emergency procedure.
i also work on development of m/softs flight simulator.
Question.
you are onboard a boeing 747-8 series.
all four engines have been lost and the plane is in a glide.
Attitude is at 43,000.
you are over the ocean.
how long do you have before you ditch into the sea?
how many miles will you glide.
closest person wins and if your into gaming and have steam i will contact you.
good luck"
This is going to annoy me because I’m a nerd and I am trying to remember what it’s etops certification without googling! 
I “think” it’s etops certification would have to be a big number because it would do transatlantic and transpacific flights… so possibly etops 240?
For the un nerds etops is the amount of minutes a plane is allowed to be from an airport where it would be possible to land if it were down to one engine….
So the answer is… a while!! |
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As I recall, a BA 747 flew through a volcanic ash cloud some years ago resulting in the temporary loss of all four engines. It then became the largest glider on the planet until the driver managed to get the engines working again. I don't remember how long this took though I imagine that to all involved it felt a lot, lot longer than it actually took. I reckon the pilot earned his pay, and then some, that day. |
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By *4bim OP Man
over a year ago
Farnborough Hampshire |
"As I recall, a BA 747 flew through a volcanic ash cloud some years ago resulting in the temporary loss of all four engines. It then became the largest glider on the planet until the driver managed to get the engines working again. I don't remember how long this took though I imagine that to all involved it felt a lot, lot longer than it actually took. I reckon the pilot earned his pay, and then some, that day. "
you are correct. |
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I cannot accurately determine the exact time and distance of a glide without additional information, such as the wind speed and direction, the weight and balance of the aircraft, and the angle of descent. However, I can provide some general information.
In a glide, the Boeing 747-8 has a glide ratio of approximately 15:1. This means that for every 15 units of forward distance traveled, the aircraft loses one unit of altitude. Therefore, if the aircraft is at an altitude of 43,000 feet, it could glide approximately 645,000 feet or 121.5 miles (assuming no headwind or tailwind, and no obstructions in the way).
The time it takes for the aircraft to reach the surface of the ocean depends on the vertical speed of descent, which in turn is affected by the glide angle and airspeed. A typical glide angle for a commercial airliner is around 3 degrees, which means the aircraft would lose about 1,000 feet of altitude for every 3 nautical miles (5.5 kilometers) of forward distance traveled. The airspeed also plays a role in the descent rate; a higher airspeed would result in a steeper glide angle and faster descent.
Without more specific information, it is difficult to provide an accurate estimate of the time and distance of the glide. |
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I promise absolutely no googling.
Just going by gut instinct.
I'm assuming a gliding descent rate of 5,000 ft a minute. I'm assuming a gliding airspeed of 20 mph. I'm assuming all other electrical systems / flaps can be operated as normal.
8 mins, 30 secs before touchdown.
Hopefully land within glide range of 2.805 miles ! |
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I’d assume the following.
The aircraft was at normal cruising speed when suddenly all 4 engines are lost… so maybe 500mph?
I’m going to guess at a deceleration of 50mph every 30 seconds while maintaining a glide that drops 5000 (you don’t specify the units so assuming feet) a minute.
So rough maths means you’d stall before reaching the sea at that glide rate… so you’d need a steeper dive to maintain airspeed long enough… hmmm… I’m going to guess..
3 minutes so that you’re ditching while still travelling with enough airspeed to keep the nose up… say 100mph on ditching…
Ok 3 minutes… average speed over decent of 300mph, so you’d have gone 15 miles in that 3 minutes |
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By *4bim OP Man
over a year ago
Farnborough Hampshire |
the answer.
here is a quick video from one of the simulator streams.
https://www.youtube.com/watch?v=1mgsDUuhXyk&list=LL&index=2
the answer is: 30 minutes approx gliding.
distance 184 miles
_wantyourwife was closest with 30 minutes and 200 miles.
well done. if you would like to mail me and you have steam on you pc let me know what game you like and i'll send a activation code to you.
thanks everyone for getting involved.
i will do another question next month. |
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By (user no longer on site)
over a year ago
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"after PW asked why people dont start new threads i will ask a question for you all to guess the answer.
its just for fun so please do not google or youtube as my video on there will reveal the answer. and yes i am a qualified pilot who has done this in a simulator for an emergency procedure.
i also work on development of m/softs flight simulator.
Question.
you are onboard a boeing 747-8 series.
all four engines have been lost and the plane is in a glide.
Attitude is at 43,000.
you are over the ocean.
how long do you have before you ditch into the sea?
how many miles will you glide.
closest person wins and if your into gaming and have steam i will contact you.
good luck"
Big difference between attitude and altitude. Trick question. |
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