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Posted: 10/18/2022 7:04:57 PM EST
[#1]
Quote HistoryQuoted: No matter what the FAA print (or requires aircraft manufacturers to print), the airplane remains an all-attitude vehicle. And, as such, there's no such thing as "stall speed". Failing to understand that you can exceed the critical AOA of the wing at any speed, or that you can still have plenty of lift and control of aircraft well below the straight-and-level-at-a-particular-weight-and-temperature "stall speed", is a very dangerous thing. You know that there is a whole segment of the professional aviation world that doesn't use "V speeds", right? Next time I get into an accelerated stall, I'll be sure to remind myself that "this isn't happening, I'm above the stall speed!" Again, lol. Since you’re a pilot, I’m sure you’re well aware that this topic is very well covered immediately when you begin flight instruction. Angle of attack is like the very first thing you learn about. It’s all over the books and tests, CFI’s drill it into you, and you can count on the DPE making sure you understand it before signing off on your ticket. Pretty much anybody flying airplanes understands this. The idea that you are getting butt-hurt at people who don’t fly airplanes for using a term that is well-accepted in aviation (the FAA uses it, and it’s in most POH’s) is stupid. People who aren’t pilots that are reading and participating in this thread are not going to be killed because they don’t know all nuances of the term “stall speed”. Also, awesome accelerated stall story, bro! |
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Posted: 10/18/2022 7:05:58 PM EST
[#2]
Quote HistoryQuoted: It's a matter of perspective, ackshually. A fundamental understanding of aerodynamic theory is required of a competent pilot. This applies to everyone, irrespective of airframe. The POH for a given platform is largely written for the intended audience, ie; the level of detail in a 152/172 manual is markedly different than that of a NATOPS manual for a Hornet. The term "stall speed" is used as a generic term that is easily understood by the casual user or someone who may not be inclined to maintain peak proficiency. That does not excuse the user from having a clear understanding of how the vehicle works. As stated earlier, many people have lost their lives by having a cursory understanding of terminology and making assumptions that proved fatal. Duke Yawn. See reply above. |
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Posted: 10/18/2022 7:14:57 PM EST
[#3]
Quote HistoryQuoted: You can actually float a 172 backwards in relation to the ground with enough of a headwind. I forget what the stall speed is but it's pretty low, like 40 knots I think. Stall speed of a generic 172 is 54 MPH / 47 knots in landing configuation, 61 MPH clean. A Cessna 150 is 48 MPH / 42 knots. I've gone backwards in a 150 many times. |
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Posted: 10/18/2022 7:17:15 PM EST
[#4]
Quote HistoryQuoted: It probably sounded like it was slowing down as it got further away due to Doppler effect. It was going faster than 50-60 unless it was on final coming in to land. Depends. I’ve done 140 indicated but only 80 across the ground |
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Posted: 10/18/2022 7:22:08 PM EST
[#5]
Quote HistoryQuoted: A C172 will comfortably fly at 40mph or so. Stall is 36, IIRC. I would have to pull my POH. I have landed and pulled off the taxi way in less than 100 feet of ground roll. This. Land at 40 kias. He was probably just doing slow flight just out Looking around. TC |
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Posted: 10/18/2022 7:23:49 PM EST
[#6]
Quote HistoryQuoted: I am an aviation novice (newly certificate private pilot), so please excuse my ignorance. As I understand it: 1) Most if not all airplanes have published stall speeds. There is usually Vs0, which is stall speed in landing configuration (i.e. full flaps) and Vs1, which is stall speed in clean configuration. These assume level flight. IIRC the Vs0 for a 172 is 38 knots indicated. 2) It is possible to stall an aircraft at any speed. The variables are angle of attack (AOA) and angle of bank. You could be flying at a level attitude, but if you bank into a steep enough turn, you would produce an accelerated stall. Similarly, you could be flying wings level, but whatever your speed, if you pitch up enough (at least in normal airplanes) you will eventually exceed the critical angle of attack and stall. Am I mistaken? Sounds good to me. Welcome to the club.  TC |
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Posted: 10/18/2022 7:27:57 PM EST
[#7]
Quote HistoryQuoted: Yep. The only way to recover from slow flight is to drop the nose and get proper airspeed back , not something I would attempt at 400 ft. You can firewall a 172 in slow flight but it won't change anything until you level the aircraft by dropping the nose. You just release back pressure. I don’t even think you’d lose any altitude. It’s not like you’re at max altitude and don’t have the bite on the prop. Go full power and it will accelerate in level flight. You get high altitude and stall and you have no option. Slow flight at three feet above the runway (balked landing), firewall it and you climb out. Little airplanes are forgiving unless you’re an idiot or arrogant. Give it proper respect and you’re good. TC |
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Posted: 10/18/2022 7:30:00 PM EST
[#8]
Quote HistoryQuoted: No matter what the FAA print (or requires aircraft manufacturers to print), the airplane remains an all-attitude vehicle. And, as such, there's no such thing as "stall speed". Failing to understand that you can exceed the critical AOA of the wing at any speed, or that you can still have plenty of lift and control of aircraft well below the straight-and-level-at-a-particular-weight-and-temperature "stall speed", is a very dangerous thing. You know that there is a whole segment of the professional aviation world that doesn't use "V speeds", right? Next time I get into an accelerated stall, I'll be sure to remind myself that "this isn't happening, I'm above the stall speed!" Alpha is a motherfucker.  TC |
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Posted: 10/18/2022 7:55:04 PM EST
[#9]
Quote HistoryQuoted: [/color] I used to live on flight path of WPAFB when they were still flying C-5's there. Those things looked like they were going to fall out of the sky sometimes. They are at bgr frequently doing touch and go's.. And the antonov's. a lot of c17's but they are a little less impressive, amazing plane though. They certainly just don't look like they should be staying in the air. |
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Posted: 10/18/2022 8:27:42 PM EST
[#10]
Quote HistoryQuoted: Stall speed of a generic 172 is 54 MPH / 47 knots in landing configuation, 61 MPH clean. A Cessna 150 is 48 MPH / 42 knots. I've gone backwards in a 150 many times. The only measurement that is constant in terms of where an airplane will stall is the angle of attack... and that can vary based on load factor.  |
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Posted: 10/18/2022 9:02:33 PM EST
[#11]
Quote HistoryQuoted: It's a matter of perspective, ackshually. A fundamental understanding of aerodynamic theory is required of a competent pilot. This applies to everyone, irrespective of airframe. The POH for a given platform is largely written for the intended audience, ie; the level of detail in a 152/172 manual is markedly different than that of a NATOPS manual for a Hornet. The term "stall speed" is used as a generic term that is easily understood by the casual user or someone who may not be inclined to maintain peak proficiency or fly the aircraft to it's maximum potential. That does not excuse the user from having a clear understanding of how the vehicle works. As stated earlier, many people have lost their lives by having a cursory understanding of terminology and making assumptions that proved fatal. Duke None of what you say is wrong but your and the other guy’s posts smack of “I fly fighters and you don’t” elitism. Again, primary training aircraft almost never have AOA indicators and they definitely don’t have air data computers. Accelerated stalls are taught in primary training. Demonstrated perhaps not, but taught. So is the ever present stall-spin danger in the pattern. Every student gets the “airplane can stall at any attitude at any airspeed” but let’s face it, 172s don’t usually get vertical. They aren’t hornets. There’s nothing wrong with using the terminology “stall speed” as long as the understanding exists that a certain IAS may or may not result in a stall depending on load factor/weight/weather etc…. So yeah, while you’re not wrong, you’re still the achktually guy. |
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Posted: 10/18/2022 11:10:52 PM EST
[#12]
Quote HistoryQuoted: None of what you say is wrong but your and the other guy’s posts smack of “I fly fighters and you don’t” elitism. Again, primary training aircraft almost never have AOA indicators and they definitely don’t have air data computers. Accelerated stalls are taught in primary training. Demonstrated perhaps not, but taught. So is the ever present stall-spin danger in the pattern. Every student gets the “airplane can stall at any attitude at any airspeed” but let’s face it, 172s don’t usually get vertical. They aren’t hornets. There’s nothing wrong with using the terminology “stall speed” as long as the understanding exists that a certain IAS may or may not result in a stall depending on load factor/weight/weather etc…. So yeah, while you’re not wrong, you’re still the achktually guy. It's all so tiresome..I don't fly fighters for a living although a good number of my buddies still actively do. This being GD , I should have known better than to chime in. My intent was to simply encourage folks like that new private pilot to dig a little deeper into theory, broaden his knowledge base and gain a better understanding of the machines he intends to operate. But I think you probably knew that. Carry on.... Duke |
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Posted: 10/18/2022 11:16:20 PM EST
[#13]
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Posted: 10/18/2022 11:27:21 PM EST
[#14]
Quote HistoryQuoted: It probably sounded like it was slowing down as it got further away due to Doppler effect. It was going faster than 50-60 unless it was on final coming in to land. |
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Posted: 10/19/2022 6:49:38 AM EST
[#15]
Quote HistoryQuoted: It's all so tiresome..I don't fly fighters for a living although a good number of my buddies still actively do. This being GD , I should have known better than to chime in. My intent was to simply encourage folks like that new private pilot to dig a little deeper into theory, broaden his knowledge base and gain a better understanding of the machines he intends to operate. But I think you probably knew that. Carry on.... Duke Because someone uses “stall speed,” they don’t know the theory? Quite the assumption. You’re a genius and nobody else is, obviously. |
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Posted: 10/19/2022 7:09:37 AM EST
[#16]
Quote HistoryQuoted: You just release back pressure. I don’t even think you’d lose any altitude. It’s not like you’re at max altitude and don’t have the bite on the prop. Go full power and it will accelerate in level flight. You get high altitude and stall and you have no option. Slow flight at three feet above the runway (balked landing), firewall it and you climb out. Little airplanes are forgiving unless you’re an idiot or arrogant. Give it proper respect and you’re good. TC Level is the key, ground effect comes in to play also. |
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Posted: 10/19/2022 7:38:44 AM EST
[#17]
Just look at the stall speed for the aircraft, should be be around 45 or so indicated speed.
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Posted: 10/19/2022 7:49:58 AM EST
[#18]
Quote HistoryQuoted: Just look at the stall speed for the aircraft, should be be around 45 or so indicated speed. tHeReS nO sUcH tHiNg aS sTaLl sPeEd |
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Posted: 10/19/2022 8:28:36 AM EST
[#19]
Tractor beams from UFOs have been known to slow down or stop aircraft in mid flight. Did you notice any strange lights or sounds at the time.
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Posted: 10/19/2022 8:43:35 AM EST
[#20]
All this talk of stall speed and AoA... I was taught that it was based on Reynolds number.
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Posted: 10/19/2022 8:49:44 AM EST
[#21]
Quote HistoryQuoted: All this talk of stall speed and AoA... I was taught that it was based on Reynolds number. We're talking airplanes, not aluminum foil. Try and keep up, would ya? |
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Posted: 10/19/2022 11:20:20 AM EST
[#22]
Quote HistoryQuoted: All this talk of stall speed and AoA... I was taught that it was based on Reynolds number. Now we're talkin'. |
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Posted: 10/19/2022 11:25:39 AM EST
[#23]
Quote HistoryQuoted: your and the other guy’s posts smack of “I fly fighters and you don’t” elitism. Gotta love GD. If you don't like what they're saying, then just make them into 1-dimensional characters so you can discredit it. Nice. |
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Posted: 10/19/2022 11:39:25 AM EST
[#24]
Quote HistoryQuoted: Gotta love GD. If you don't like what they're saying, then just make them into 1-dimensional characters so you can discredit it. Nice. Gotta love people wil can’t read, as there was no attempt to discredit anything. I even stated that your and the other guy’s comments were technically correct. Stall speed DOES exist. It’s how you measure where the stall will occur when there’s no means to indicate that critical AOA has been exceeded. There’s no indicator in a typical bugsmasher. You can’t input weight anywhere either. You’ve got the performance charts in the POH and an ASI…and that’s it. Ok, the seat of your pants too. Can make a poor instrument as your comment about pilots killing the selves demonstrates. |
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Posted: 10/19/2022 11:42:39 AM EST
[#25]
Quote HistoryQuoted: It’s how you measure where the stall will occur when there’s no means to indicate that critical AOA has been exceeded. You know, outside of the loss of lift, the loss of altitude, wing drop/wing rock, possible the dropping of the nose depending on aircraft design. Not to mention all of those other performance indicators leading up to a stall like aiframe buffeting, loss of aileron authority, etc, leading up to the stall. Outside of that, yeah. No means. |
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Posted: 10/19/2022 11:44:28 AM EST
[#26]
Quote HistoryQuoted: You know, outside of the loss of lift, the loss of altitude, possible the dropping of the nose depending on aircraft design. Not to mention all of those other performance indicators leading up to a stall like aiframe buffeting, loss of aileron authority, etc, leading up to the stall. Outside of that, yeah. No means. Things that I also mentioned. I’m not the one who brought up AOA Indicators and ADCs in a discussion about a Cessna. Published speeds are clearly for pilots who aren’t brilliant like you. |
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Posted: 10/19/2022 11:45:26 AM EST
[#27]
normally for a 172M, when you are trimmed for best glide with the engine power at idle, your IAS is Mach 1.25
I am surprised Op didn't hear the sonic boom |
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Posted: 10/19/2022 11:51:53 AM EST
[#28]
Quote HistoryQuoted: Things that I also mentioned. I’m not the one who brought up AOA Indicators and ADCs in a discussion about a Cessna. Quote HistoryQuoted: Things that I also mentioned. I’m not the one who brought up AOA Indicators and ADCs in a discussion about a Cessna. Neither did I. Quoted: Published speeds are clearly for pilots who aren’t brilliant like you. Again, the ad hominem. I'm not putting other posters down, either their skills or experience, nor am I playing some skills or experience card I have. Why do you have the need to do that? |
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Posted: 10/19/2022 12:08:18 PM EST
[#29]
Quote HistoryQuoted: Neither did I. Again, the ad hominem. I'm not putting other posters down, either their skills or experience, nor am I playing some skills or experience card I have. Why do you have the need to do that? Ad hominem? I haven’t insulted you at all. The fact is that your comment “airspeed doesn’t exist” is false, it’s published in every GA POH. Yeah, they don’t apply to your jet. We get it. |
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Posted: 10/19/2022 12:23:07 PM EST
[#30]
Quote HistoryQuoted: Yeah, they don’t apply to your jet. We get it. Which comments, exactly, are the ones about a jet? Not saying it is an "insult". I'm saying all of these passive-aggressive drive-bys are an ad hominem argument. Can't your points stand on their own merit without that? |
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Posted: 10/19/2022 12:28:35 PM EST
[#31]
Quote HistoryQuoted: Which comments, exactly, are the ones about a jet? “There is an entire segment of professional aviation that doesn’t use stall speeds.” |
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Posted: 10/19/2022 12:31:56 PM EST
[#32]
Quote HistoryQuoted: Ad hominem? I haven’t insulted you at all. The fact is that your comment “airspeed doesn’t exist” is false, it’s published in every GA POH. Yeah, they don’t apply to your jet. We get it. As much as I enjoy a good purse swinging argument in GD, this one has delivered in spades, how about we agree on this: In the ABSENCE of an integrated suite of sensors, AOA/ADC/HUD/ real time CGcalcs/ etc., manufacturers' published stall speeds serve a useful purpose. They provide a baseline number that is easily memorized by the operator as in " hey, I'm approaching that speed I remember reading about and I should be paying additiional attention to what the hell is going on here". Beyond that, the student should be taught that there are agravating factors, sudden onset of high alpha/ low radius turns etc. that render those numbers invalid. While the term "stall speed" , without further explananation may make an engineers eye twitch, yes it is a common term that does have some utility when operating a low performance aircraft. Duke |
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Posted: 10/19/2022 12:33:07 PM EST
[#33]
Quote HistoryQuoted: As much as I enjoy a good purse swinging argument in GD, this one has delivered in spades, how about we agree on this: In the ABSENCE of an integrated suite of sensors, AOA/ADC/HUD/ real time CGcalcs/ etc., manufacturers' published stall speeds serve a useful purpose. They provide a baseline number that is easily memorized by the operator as in " hey, I'm approaching that speed I remember reading about and I should be paying additiional attention to what the hell is going on here". Beyond that, the student should be taught that there are agravating factors, sudden onset of high alpha/ low radius turns etc. that render those numbers invalid. While the term "stall speed" , without further explananation may make an engineers eye twitch, yes it is a common term that does have some utility when operating a low performance aircraft. Duke 100% agree. |
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Posted: 10/19/2022 12:35:29 PM EST
[#34]
Quote HistoryQuoted: “There is an entire segment of professional aviation that doesn’t use stall speeds.” Actually, I said "V speeds", which was in response to your posting a link to an article about V speeds, which was supposed to be further proof of something (?). And, yes, there are lots of aircraft that weren't designed under FAA Part 23/25 certification standards or don't fly on FAA airworthiness certificates, and thus don't use V-speeds. That had nothing to do whatsoever with the stall speed as an analog for critical AOA discussion. |
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Posted: 10/19/2022 12:39:49 PM EST
[#35]
Quote HistoryQuoted: Actually, I said "V speeds", which was in response to your posting a link to an article about V speeds, which was supposed to be further proof of something (?). And, yes, there are lots of aircraft that weren't designed under FAA Part 23/25 certification standards or don't fly on FAA airworthiness certificates, and thus don't use V-speeds. That had nothing to do whatsoever with the stall speed as an analog for critical AOA discussion. Yeah I know, paraphrased, sorry. I didn’t post any link. You’re mixing me up with someone else. |
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Posted: 10/19/2022 12:42:13 PM EST
[#36]
Quote HistoryQuoted: All this talk of stall speed and AoA... I was taught that it was based on Reynolds number. Says the guy with an avatar with a stall speed measured in mach. |
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Posted: 10/19/2022 12:45:08 PM EST
[#37]
Fully laden
African or European |
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