Ps76 From , joined Dec 1969, posts, RR: Posted (4 years 2 days 11 hours ago) and read 8633 times:
Hi,
Just thought I'd try to ask the following question as I have a flight in about an hour and am quite a nervous flyer. Was just wondering what the stall speed roughly of an airliner in cruise was. Near the ground with flaps out it's about 100kt? which the airplane is comfortably faster than having an approach speed of roughly 135kt?. Was just wondering how it was for the rest of the flight (I like going faster because I feel safer but sometimes worry probably unjustifably that we might be near "coffin corner" with a high stall speed in cruise). In cruise would the stall speed be more like 2 hundred and something knots indicated or .4M so the aircraft has a comfortable speed margin that it's faster by or is it something different?
Tb727 From United States of America, joined Jun 2005, 1375 posts, RR: 4 Reply 1, posted (4 years 2 days 10 hours ago) and read 8615 times:
In an airliner you aren't even close to having a coffin corner because you don't get high enough. I can't give you specific numbers because it's been awhile since I've been slow up high but we watch the stall indicators when we start getting high and slow and adjust pitch and altitude accordingly.
Lowrider From United States of America, joined Jun 2004, 3220 posts, RR: 11 Reply 2, posted (4 years 2 days 9 hours ago) and read 8600 times:
Quoting Ps76 (Thread starter): Was just wondering what the stall speed roughly of an airliner in cruise was.
Varies widely depending upon weight, altitude, CG, load factor, and temp. Stall is a matter of angle of attack, not speed. The speed you reach that angle of attack at will vary, but the angle never will.
Quoting Ps76 (Thread starter): we might be near "coffin corner" with a high stall speed in cruise
Fortunately, aeronautical engineers are fiendishly clever. The wing is designed so that the aircraft will never reach the coffin corner. You need only worry about it if you are going for a ride in a U2, or something similar.
David L From United Kingdom, joined May 1999, 9213 posts, RR: 42 Reply 3, posted (4 years 2 days 8 hours ago) and read 8544 times:
Quoting Ps76 (Thread starter): I feel safer but sometimes worry probably unjustifably that we might be near "coffin corner" with a high stall speed in cruise
Relax. The flight crew are well aware of what coffin corner means and won't go anywhere near it. They have their own lives to consider, you know.
RedFlyer From United States of America, joined Feb 2005, 4175 posts, RR: 30 Reply 4, posted (4 years 2 days 7 hours ago) and read 8532 times:
Relax. An airplane can stall at any speed. So it doesn't matter how fast you're going or how high up you are. Grip that armrest tightly my friend!
And fasten your seatbelt tightly on the way to the airport. You're far more likely to die in a car crash trying to catch your flight then you will from your pilot stalling the plane at altitude.
RoseFlyer From United States of America, joined Feb 2004, 8739 posts, RR: 52 Reply 5, posted (4 years 2 days 7 hours ago) and read 8530 times:
The only high altitude stall I have heard of is when the Pinnacle CRJ-200 operating for Northwest on a repositioning flight a few years ago crashed in Missiouri. The pilots were deviating from standard procedures and took the airplane to an unsafe condition by flying up to its max service ceiling incorrectly and ended up at an unsustainable speed so that the engines did not have enough thrust and eventually flamed out during the stall.
150 knots Mach .57 at 7.5 degrees nose up is where the stick shaker activated and the plane pitched as high as 20 degrees before stalling.
Tdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80 Reply 7, posted (4 years 1 day 19 hours ago) and read 8307 times:
Quoting Ps76 (Thread starter): Was just wondering how it was for the rest of the flight (I like going faster because I feel safer but sometimes worry probably unjustifably that we might be near "coffin corner" with a high stall speed in cruise).
The normal operating envelope of most airliners doesn't even get close to coffin corner...in order to reach it, you'd have to go considerably outside the allowable flight envelope. On current FBW airplanes, the plane will fight quite hard to prevent you from doing that.
Quoting Lowrider (Reply 2): Stall is a matter of angle of attack, not speed. The speed you reach that angle of attack at will vary, but the angle never will.
The angle can change with and without slats...hence autoslats on some aircraft.
Borism From Estonia, joined Oct 2006, 431 posts, RR: 0 Reply 9, posted (4 years 1 day 14 hours ago) and read 8238 times:
isn't KIAS stall speed the same at any altitude for the same configuration? it's the thrust and controllability that matters.
besides, unless it is unrecoverable stall, and unless you fly over Himalayas, there's plenty of altitude at cruise to recover from any stall, unlike during approach.
Lowrider From United States of America, joined Jun 2004, 3220 posts, RR: 11 Reply 10, posted (4 years 1 day 11 hours ago) and read 8182 times:
Quoting Tdscanuck (Reply 7): The angle can change with and without slats...hence autoslats on some aircraft
You might as well say, "well if I change the shape of the wing the AOA at which it stalls will change". You have now altered the characteristics of the wing. But given a fixed wing geometry, it will always stall at the same angle of attack.
Faro From Egypt, joined Aug 2007, 1443 posts, RR: 0 Reply 12, posted (4 years 1 day 10 hours ago) and read 8148 times:
Quoting RedFlyer (Reply 4): Relax. An airplane can stall at any speed. So it doesn't matter how fast you're going or how high up you are. Grip that armrest tightly my friend!
True until you have a thrust-to-weight greater than unity; not that you will ever find that on airliners, the highest ratio I have seen are for the venerable YAK-40 and its sibling the YAK-42 at over 0.4 IIRC. Technically you are then limited by the thrust which diminishes with altitude and therefore air density.
Vikkyvik From United States of America, joined Jul 2003, 8209 posts, RR: 28 Reply 13, posted (4 years 1 day 8 hours ago) and read 8103 times:
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Quoting Faro (Reply 12): True until you have a thrust-to-weight greater than unity; not that you will ever find that on airliners, the highest ratio I have seen are for the venerable YAK-40 and its sibling the YAK-42 at over 0.4 IIRC. Technically you are then limited by the thrust which diminishes with altitude and therefore air density.
The airplane wing still stalls, if you exceed the stall AOA, irrespective of your thrust-to-weight ratio.
Of course, it may not matter as much
"Two and a Half Men" was filmed in front of a live ostrich.
Borism From Estonia, joined Oct 2006, 431 posts, RR: 0 Reply 14, posted (4 years 1 day 8 hours ago) and read 8103 times:
Quoting Mir (Reply 11): No. Configuration has an effect, sure, but all other things being equal, a heavier airplane will stall at a faster speed than a lighter airplane.
Well, I meant the same aircraft and the same wing and the same weight, obviously. Why would I compare apples to oranges?
But of course aircraft becomes lighter while climbing to cruise alt., not heavier, thus flight envelope widens slightly.
Faro From Egypt, joined Aug 2007, 1443 posts, RR: 0 Reply 15, posted (4 years 1 day 7 hours ago) and read 8087 times:
Quoting Vikkyvik (Reply 13): Quoting Faro (Reply 12):
True until you have a thrust-to-weight greater than unity; not that you will ever find that on airliners, the highest ratio I have seen are for the venerable YAK-40 and its sibling the YAK-42 at over 0.4 IIRC. Technically you are then limited by the thrust which diminishes with altitude and therefore air density.
The airplane wing still stalls, if you exceed the stall AOA, irrespective of your thrust-to-weight ratio.
Of course, it may not matter as much
Spot on!
What I should have posted is that with a thrust-to-weight ratio greater than one, you have the option of *not* stalling at any nose-up attitude you may wish up to full vertical. Of course you can still stall by not making use of all that thrust and happily exceeding stall AOA in the process.
474218 From United States of America, joined Oct 2005, 6340 posts, RR: 10 Reply 16, posted (4 years 1 day 6 hours ago) and read 8055 times:
Quoting Ps76 (Thread starter): Just thought I'd try to ask the following question as I have a flight in about an hour and am quite a nervous flyer.
Quoting Ps76 (Reply 6): I survived my flight(!) and hopefully I'm getting a little better with regard to my nerves flying(!)
I found your curiosity about stalls very interesting: Many years ago I was teaching an after hours class at the L-1011 production facility in California. One class about five students that all worked together were absent. At the next session a asked where they all were. It seems they completed their work on an airplane on time, under budget and with no squawks and their reward was a ride on an L-1011 production test flight. However, flight they were on was attempting to induce compressor stalls in the No. 2 engine, which consisted of reducing the speed and increasing the angle of attack until either the aircraft of the engine stalled. They even landed once to tweak the fuel controller, but would not let anyone off (they were on the manifest and had to complete the flight). They all said they were scared to death and would never do it again.
David L From United Kingdom, joined May 1999, 9213 posts, RR: 42 Reply 17, posted (4 years 1 day 6 hours ago) and read 8055 times:
Quoting Faro (Reply 15): Of course you can still stall by not making use of all that thrust and happily exceeding stall AOA in the process.
... which brings up yet another safety buffer. Airline pilots will not only be concerned that they don't kill themselves but will also be concerned that they don't lose their jobs. The threshold for being fired is generally much lower than the threshold for putting their lives at risk... in most cases.
Lowrider From United States of America, joined Jun 2004, 3220 posts, RR: 11 Reply 18, posted (4 years 1 day 6 hours ago) and read 8053 times:
Quoting David L (Reply 17): Airline pilots will not only be concerned that they don't kill themselves but will also be concerned that they don't lose their jobs. The threshold for being fired is generally much lower than the threshold for putting their lives at risk... in most cases
Of course, after killing yourself, the loss of job usually becomes secondary consideration.
Mir From United States of America, joined Jan 2004, 19700 posts, RR: 56 Reply 20, posted (4 years 1 day 5 hours ago) and read 8021 times:
Quoting Borism (Reply 14): Well, I meant the same aircraft and the same wing and the same weight, obviously. Why would I compare apples to oranges?
I misunderstood the question - I read it as asking about whether stall speed was the same for a certain wing configuration at any specific altitude, in which the weight is the only variable. My apologies.
-Mir
7 billion, one nation, imagination...it's a beautiful day
OldAeroGuy From United States of America, joined Dec 2004, 3206 posts, RR: 66 Reply 24, posted (4 years 1 day 1 hour ago) and read 7954 times:
Quoting 474218 (Reply 23): Quoting OldAeroGuy (Reply 22):
It is unusual to have nonessential personnel on a high risk flight like this though
Aircraft was fully certified and flow by Lockheed personnel nothing unusual and hardly high risk.
Stall testing (airframe or engine) is defined as high risk testing by many airframers (and their insurance companies). Being certified has little to do with the risk level.
Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis
25 Tdscanuck: Well, no, because normal changes to the shape of the wing don't affect the stall AoA much. Most airfoils stall right around 21 degrees. Slats cause a
26 Lowrider: Now if only I could continue to collect a paycheck
27 Faro: Reminds me of the A310 landing incident in Orly in 1994; they went to over 60 degrees nose-up before stalling but made it safely down to the runway j
28 Aaron747: The only thing you really need to be nervous about as a passenger is terrorism of some kind - namely bombs. It's in the backs of some airline drivers
29 Borism: Perhaps you can elaborate? How many people were killed by terrorists on airplane and how many have been killed due to stall? I'm too lazy to look it
30 Avt007: I know of an F28 that stalled several times at 30,000 feet due to a stab trim runaway. It was a classic low airspeed stall, but quite violent, accordi
31 Aaron747: Just with the Air India and Pan Am incidents in the 80s, the 9/11 hijackings and the Air Zimbabwe 767 a few years back...easily over 1,000 people.
32 Ps76: Hi, Just to say many thanks for the replies etc.. I guess what might help calm me a little more would be to know the turbulence penetration speed. Whe
33 FlyASAGuy2005: In the case in 3701, they seemed to be more focused on loosing their job over surviving. It's widely debated but the fact that they tried to re-light
34 Lowrider: It all stated with poor situational awareness. The CRJ has a min climb speed for a reason. Allowing the speed to get so low, and the pitch angle so h
35 FlyASAGuy2005: Hate to get OT but from the get go, they seemed to be on a joy-ride. They were barely 400+feet AGL when they started making aggressive control movemen
36 David L: Obviously a situation where there are no passengers to complain about the flight is different to the situations we were discussing., i.e. whether or
37 Pilotpip: I disagree. The actions they took should have never happened. Both likely used the same poor judgment with passengers on board. The only difference i
38 David L: OK, back to what I was originally going to say but thought was redundant: I should have said "in the VAST majority of cases...". You might be right b
39 Pilotpip: You would be surprised how many say "sure we can go to FL380" without taking a quick glance at a performance manual to make sure they have a good buff
40 David L: So you'd say to the OP that he's right to be worried about his aircraft being taken to coffin corner? Let's just say I'm somewhat surprised by that.
41 Pilotpip: As much as I'd be concerned that the PIC paid no attention to the enroute weather and was ok with the minimum fuel going into ATL on a summer day... W
42 Aaron747: It really isn't different - as far as a pilot is concerned, you either take what you're doing (and hopefully your life as well) seriously, or you don
43 FlyASAGuy2005: Come on now. I would suggest you sift through the FDR transcript. It's an interesting read. Passengers on board or not, their actions on initial clim
44 Rwessel: In cruise your indicated airspeed is already pretty low, which is what would relate to turbulence. The *true* airspeed is high, but because of the th
45 FlyASAGuy2005: Ultimately, yes. The guys are up front know what they're doing and you shouldn't worry. Also keep in mind that dispatch is monitoring your flight. Un
46 David L: Well I'd have to reply with "come on now", too. Do you really believe they would have done that with passengers on board? Well, duh! I never said any
47 FlyASAGuy2005: You seem to be bent on that fact that it was a ferry flight thus, it was ok. With passengers, no go. I don't get that logic but I'm sure THEY do, may
48 Pilotpip: How about the actions of that ferry flight affecting a later flight with passeners? What if they had not crashed, but in their zoom climbs they exceed
49 FlyASAGuy2005: But I guess that isn't valid because it was only a ferry flight.
50 David L: Evidence, please. How many times do I need to repeat the question I was answering? Is there an equivalent to Goodwin's Law, for example, that deals w
51 FlyASAGuy2005: I'm going to say that my initial comment was geared towards below and your post about losing one's job and losing their life. I initially meant to co
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