When the windmill stops.

[Mike Gearon]

Aviate. Navigate. Communicate.

Aviate.

1. Best glide.

2. Attempt to rectify the problem. Fuel. Electrics. (I figure this is part of aviate to keep the aviate part in the air if possible)
3. Wind direction.

Navigate.

1. Awareness of the country you’ve flown over with regard to emergency landing.

2. Country ahead with regard to emergency landing.

3. Wind direction and how it would influence a decision in any direction. Say over mountains with flat ground in glide range ahead and behind you. Check airspeed to ground speed and commit to a direction. So many variables. I’d not be overthinking it.

 

Communicate.

 

1. If possible communicate with Center. 
 

I guess if you had a 50 or 60kn head wind you could sit there in the one spot to really get a handle on the whole aviate, navigate and communicate. However, it’s stuff I don’t think you want in your head. You’re sticking to your training. It keeps you calm. You’re in a process of elimination of possible courses of action. Narrowing focus to the ones you will commit to. 

[APenNameAndThatA]

This is an aviation forum, so people are obliged to callout incorrect ideas. I never managed to convince you that the mass of one litre of water was not 100 grams so here I was not going to go beyond merely pointing out to you that you are wrong. 

 

Okay, I’ll give the mass thing one more shot. The F in the formula F=ma is measured in newtons, not kg. That is how come, when it comes to gravity, it is 10 times bigger than mass. IIRC, you posted a picture of a spring scale. On one side the scale showed the force in newtons and on the other side the scale showed the force in kg. 

 

Some things do indeed never change, like you posing questions to teach people things and then getting upset when people don’t answer the way you want. Sometimes I wonder if your posts are an elaborate joke, but then I remember that you have gotten me booted off the forum for disagreeing with you. 

Edited June 26, 2022 by APenNameAndThatA

[old man emu]

9 hours ago, APenNameAndThatA said:

You didn’t ask the question to improve your own knowlege…

No, I didn't. I asked the question to stimulate thinking. Is it my idea to increase my own knowledge? Partially. Is it my idea to have student pilots think about some aspect of flight - yes. Did my twisted mind come up with this method? NO!!!!

 

Way back in the centuries BC (that's Before Computers) the Greek philosophers and teachers came up with the Socratic Method. The Socratic method is a teaching tactic in which questions are asked continually until either the student gives a wrong answer or reasoning or the teacher is satisfied with the student’s responses. Teachers usually employ this tactic to develop critical-thinking skills in students, to improve their intellectual thinking about the subject.

 

If this method is anathema to people, then I can only form the opinion that it there is no longer time in this Life to sit under a tree and ponder the Why of our activities to gain a better understanding of the How. 

[Bruce Tuncks]

I watched a power failure ( take-off from 23 Gawler) where there was a total power loss at 300 ft and nothing ahead. The pilot rurned 90 degrees and made a good landing in a safe paddock.

That stuff about "no more than 15 degrees turn" could have got him killed.

In a glider, you can do a 180 CLIMBING turn slowing from 60 to 45 knots. A jabiru loses 200 ft at most doing a similar thing. Try it at a safe height.

But I also saw a very heavy landing where a brand-new Sonex tried to do a 270 turn to land back on a runway from a similar position so the advice is not complete crap.

 

[facthunter]

There are some "concepts" that can't be left unchallenged on an aviation forum. It's a matter of safety. I saw a student crash a plane an hour after I'd heard an instructor explain something in a way I thought was contentious, when I overheard it. Nev

[RossK]

1 hour ago, old man emu said:

No, I didn't. I asked the question to stimulate thinking. Is it my idea to increase my own knowledge? Partially. Is it my idea to have student pilots think about some aspect of flight - yes. Did my twisted mind come up with this method? NO!!!!

 

Way back in the centuries BC (that's Before Computers) the Greek philosophers and teachers came up with the Socratic Method. The Socratic method is a teaching tactic in which questions are asked continually until either the student gives a wrong answer or reasoning or the teacher is satisfied with the student’s responses. Teachers usually employ this tactic to develop critical-thinking skills in students, to improve their intellectual thinking about the subject.

 

If this method is anathema to people, then I can only form the opinion that it there is no longer time in this Life to sit under a tree and ponder the Why of our activities to gain a better understanding of the How. 

You've asked a basic question and then convoluted it to try to cause confusion.

This is basic stuff straight out of the BAK, which i do think you understand, but you seem to enjoy convoluting basic concepts to cause arguments.

How is that helpful to anyone?

There is a word for people that do this on forums.

 

[Bruce Tuncks]

I reckon there are some things which may well be correct on heavy planes but do not apply so exactly to the light stuff we fly. But the second pilot ( the one who tried the 270 degree turn from 300 ft in the Sonex) was a recently retired 747 check captain...

[facthunter]

The same laws of physics apply to all planes unless they fly supersonic.. The energy levels are much higher. Mass and velocity equals a lot of kinetic energy.. When you are accelerating and decelerating.. A VH or U/L instructor would do more landings in a day than a B 747 driver in a month and on maybe 3 different planes on that day.

  When you fly the line you don't change the type of plane.  You may fly several versions of it. You also have to stop applying characteristics from the plane you flew onto the one you are  converting onto.. A complex plane takes about 6 weeks to convert onto pretty much full  time followed with about a month on the  line with a training captain.  There also may be specific route endorsements required to be current on. Nev

[robinsm]

I would have thought that the best effort would be put into finding a convenient landing spot and concentrating on that, not recalling master of physics lessons andsecond guessing the initial decision which was to land safe.   Laws of physics and convoluted theories are great in the classroom but when the excrement hits the revolving thing get practical.   Always fly assuming you will need a safe landing spot at any time.

 

[facthunter]

Let's not exaggerate. BASIC physics is a necessary part of operating a powered aerodynamic vehicle to it's limits. Maintain control is a prerequisite to  success.. Don't fly over what you can't land on applies to some types. OFF field landings on big stuff is "what if" stuff.  AND often the chosen field is not up to expectations when you get near it so how well you handle it determines your fate.  Fly the plane as far into the crash as you can. Nev

[aro]

21 hours ago, old man emu said:

Are you able to show mathematically that an aircraft of 500 kg at 2000' agl  with a wind of 10 kts will hit the deck at the same time headwind or tailwind?

Of course you can. It's part of BAK.

 

Rate of descent = power required / mass.

 

Power required = drag * TAS.

 

Drag = parasite drag + induced drag.

 

Parasite drag is proportional to airspeed squared.

 

Induced drag is more complicated, but it is inversely proportional to the square of the airspeed.

 

Airspeed, airspeed, airspeed. It's always airspeed. Headwind or tailwind, the airspeed doesn't change, so the power required doesn't change and the rate of descent doesn't change.

[RFguy]

nicely put. Suggest transpose the order - 

 

as otherwise you have parameters used before they are known/explained. easier for folks to understand that way.

 

IE transpose to :

 

Parasite drag is proportional to airspeed squared.

Induced drag is more complicated, but it is inversely proportional to the square of the airspeed.

 

Drag = parasite drag + induced drag.

Power required = drag * TAS.

Rate of descent = power required / mass.

 

 

Edited June 27, 2022 by RFguy

[old man emu]

10 hours ago, RossK said:

There is a word for people that do this on forums.

Gone.

[aro]

22 hours ago, old man emu said:

If you ask a question for the sake of better knowledge, you immediately get attacked for being a fool.

 

12 hours ago, old man emu said:

The Socratic method is a teaching tactic in which questions are asked continually until either the student gives a wrong answer or reasoning or the teacher is satisfied with the student’s responses.

No-one is objecting to the questions. It's the answers people have issues with.

 

You are casting yourself as a teacher, but frequently the answers you come up with are very wrong. People on the forum point it out and provide corrected answers, but you get offended because you don't get the respect you think you deserve as a teacher. There are enough experts on this forum that we can pretty quickly work out who posts reliable answers and make our own decisions. But it is an internet forum - if you post stuff, people will critique and argue with it if they disagree.

[APenNameAndThatA]

13 hours ago, old man emu said:

No, I didn't. I asked the question to stimulate thinking. Is it my idea to increase my own knowledge? Partially. Is it my idea to have student pilots think about some aspect of flight - yes. Did my twisted mind come up with this method? NO!!!!

 

Way back in the centuries BC (that's Before Computers) the Greek philosophers and teachers came up with the Socratic Method. The Socratic method is a teaching tactic in which questions are asked continually until either the student gives a wrong answer or reasoning or the teacher is satisfied with the student’s responses. Teachers usually employ this tactic to develop critical-thinking skills in students, to improve their intellectual thinking about the subject.

 

If this method is anathema to people, then I can only form the opinion that it there is no longer time in this Life to sit under a tree and ponder the Why of our activities to gain a better understanding of the How. 

OME, you are not in a position to teach other people in the forum because the people who you try and teach understand your questions better than you do. 

 

OME, you are not using Socratic questioning. You asked one question a the start, and then were mostly making wrong statements. Socratic questioning involves leading students, step by step, question by question until they learn something they already knew, as it were. 

 

I can just imagine Socrates asking his students questions where he's not as smart as them, and becoming more and more frustrated when they don't answer the questions the way he wants them to, and telling them how upset they make him. 

 

I just saw OME write "gone" on the forum. Maybe he's going to disappear for another 12 months. While he's away, maybe he'll work out that the mass of one litre of water is not 100 g.  

 

So, then Socrates would storm off out of the forum. 

 

[APenNameAndThatA]

3 hours ago, aro said:

Of course you can. It's part of BAK.

 

Rate of descent = power required / mass.

 

Power required = drag * TAS.

 

Drag = parasite drag + induced drag.

 

Parasite drag is proportional to airspeed squared.

 

Induced drag is more complicated, but it is inversely proportional to the square of the airspeed.

 

Airspeed, airspeed, airspeed. It's always airspeed. Headwind or tailwind, the airspeed doesn't change, so the power required doesn't change and the rate of descent doesn't change.

I notice that OME did not acknowledge this answer. The first time I remember OME posting a question on the forum, he was trying to say that if an aircraft was trimmed in cruise and lost some power, it would slow down. I pointed out that if a trimmed aircraft loses some power, it will descend rather than slow down. Crickets. To be fair, he did acknowledge someone was right when he said that the lift equation was based on true airspeed rather than IAS and he was corrected.

 

I didn't even think of those equations. I just thought that the issue fell outside the equations because the aircraft moved with the air mass.  

[Thruster88]

On 26/06/2022 at 9:11 PM, onetrack said:

Glide performance - https://skybrary.aero/articles/glide-performance

 

IMO, OME's wording in the first post is not correct. You wouldn't "swing around to the reciprocal direction of the forecast wind, and use it to maintain airspeed to maintain flying for longer".

 

You'd only want to swing 180° to reduce GS at the landing site - and you'd need to know if the wind speed at ground level at your chosen landing site, was strong enough to warrant a reversal of direction, that would make a major difference to GS in a deadstick landing. Of course, the terrain also has to come into the decision-making for a forced landing site.

A tailwind forced landing on an uphill slope would work out O.K., but a tailwind forced landing on a downhill slope, I would imagine is pretty much a nightmare scenario.

 

As I previously said, I'd be trying to avoid aircraft energy loss and altitude loss, caused by carrying out a 180° turn.

We should not be afraid to maneuver our aircraft with the prop stopped. Airspeed is controlled with the stick and at best glide speed, typically about 1.4 times stall speed the aircraft  WILL NOT STALL in a 30° banked turn. The load factor and increase in stall speed in a 30° banked turn is minimal, the rate of increase in decent is minimal. 

 

A 30° banked turn at 70knot gives a turn Radius of just 230 metres, pretty tight so no need to push any harder.  As we saw in the recent forced landing in SE QLD the pilots choice of field changed as he got lower, turn onto final at 100 feet, no problem.  

[old man emu]

Here is the original question:

On 22/06/2022 at 5:25 PM, old man emu said:

Suppose that you were going on trip. You obtain the forecast winds and create your flight plan, and you find that the winds will be anything other than headwinds not more than about 10 degrees either side of your desired track. Things are going well, and you find that the wind forecast is pretty spot on. Then the propeller jerks to a stop.

 

Do you continue on track, looking for a place to land, or do you swing around the the reciprocal direction of the forecast wind, and use it to maintain airspeed to maintain flying for longer while you search for a place to put down? 

The first modifier was that your Desired Track had did not involve a full-on headwind, or maybe there was a tailwind component.

The first error I made in posing the question was to write " looking for a place to land". If you delete those words, I believe it clarifies the point of the question and directs discussion towards the point being enquired about - does the direction of unpowered flight with reference to wind direction affect the TIME it takes for an aircraft to lose altitude?

 

The discussion then turned to "ranging", which, if I'm correct, is related to Ground Speed, not Airspeed. 

 

The question of altitude loss in turns was also brought up. Perhaps the words "swing around" were a poor choice, implying something like a split-arsed turn. As Thruster88 has shown above, one can make a gentle turn without significant increase in load factor that would require increased air speed to overcome. From his graph, an angle of bank of about 20 degrees make a relatively insignificant increase in load factor.

 

Finally, the words "while you search for a place to put down?" could have caught another red herring. The initial need when this unexpected event occurs would be time to think and decide on which course of action to take. Wouldn't the first step be to try to determine why the windmill stopped? Maybe getting it spinning again could be as simple as changing tanks.

 

Robinsm said, I would have thought that the best effort would be put into finding a convenient landing spot and concentrating on that, not recalling master of physics lessons  Identifying situations and developing procedures to minimise them are the basic steps in Risk Management. Better to learn the procedures well before they might need to be used, than trying to reinvent the wheel in the middle of a situation. Isn't that what ground schooling is all about?

 

Finally, I posed the question for the simple reason that I didn't know the answer. Isn't what this particular section of the Forum is all about? I was not trying to be didactic. If I posed further questions it was because the replies while correct of themselves, were not dealing with the point of my enquiry.

 

I'm sorry if that sometimes I ask for calculations to be shown. Everyone learns in their own way. The meaning of some words can be subjective, while hard, cold numbers can only be objective. I happen to be a person who needs the objective.

[aro]

44 minutes ago, old man emu said:

does the direction of unpowered flight with reference to wind direction affect the TIME it takes for an aircraft to lose altitude?

No it does not - because you are flying in and moving with the air. Without reference to the ground, you can't even tell which way the wind is blowing. The aircraft performance does not change whichever direction you fly.

[RFguy]

It's not a boat on the water,  nor a kite tethered to a fixed point.  we are flying in a parcel of air.

 

Edited June 27, 2022 by RFguy

[Mike Gearon]

1 hour ago, aro said:

No it does not - because you are flying in and moving with the air. Without reference to the ground, you can't even tell which way the wind is blowing. The aircraft performance does not change whichever direction you fly.

I learned this flying paraglides. It feels so strange to turn into the wind. Except you aren’t. You’re turning within the parcel of air. It’s only ground speed and track knows it.

[RFguy]

I think people's misconceptions come from sailing yachts. turn into the wind etc and the boat stops.

 

different to say being underwater in a current- you are 'flying' in a parcel of fluid.

in this case it's water ! as a scuba diver you know all about drift currents ----and the only way you know you are drifting is your position relative to the bottom.

If the bottom is silted or deep so you cannot resolve it, you have absolutely no idea you are drifting at all ! and you can drift a long way from your boat without realising it.

Edited June 28, 2022 by RFguy

[APenNameAndThatA]

3 hours ago, old man emu said:

Here is the original question:

The first modifier was that your Desired Track had did not involve a full-on headwind, or maybe there was a tailwind component.

The first error I made in posing the question was to write " looking for a place to land". If you delete those words, I believe it clarifies the point of the question and directs discussion towards the point being enquired about - does the direction of unpowered flight with reference to wind direction affect the TIME it takes for an aircraft to lose altitude?

 

The discussion then turned to "ranging", which, if I'm correct, is related to Ground Speed, not Airspeed. 

 

The question of altitude loss in turns was also brought up. Perhaps the words "swing around" were a poor choice, implying something like a split-arsed turn. As Thruster88 has shown above, one can make a gentle turn without significant increase in load factor that would require increased air speed to overcome. From his graph, an angle of bank of about 20 degrees make a relatively insignificant increase in load factor.

 

Finally, the words "while you search for a place to put down?" could have caught another red herring. The initial need when this unexpected event occurs would be time to think and decide on which course of action to take. Wouldn't the first step be to try to determine why the windmill stopped? Maybe getting it spinning again could be as simple as changing tanks.

 

Robinsm said, I would have thought that the best effort would be put into finding a convenient landing spot and concentrating on that, not recalling master of physics lessons  Identifying situations and developing procedures to minimise them are the basic steps in Risk Management. Better to learn the procedures well before they might need to be used, than trying to reinvent the wheel in the middle of a situation. Isn't that what ground schooling is all about?

 

Finally, I posed the question for the simple reason that I didn't know the answer. Isn't what this particular section of the Forum is all about? I was not trying to be didactic. If I posed further questions it was because the replies while correct of themselves, were not dealing with the point of my enquiry.

 

I'm sorry if that sometimes I ask for calculations to be shown. Everyone learns in their own way. The meaning of some words can be subjective, while hard, cold numbers can only be objective. I happen to be a person who needs the objective.

You posted the question because you did not know the answer? Really? Is that how come you argued with the replies? 😆

[sfGnome]

This is an interesting thread. I’ve learned a number of things that I otherwise wouldn’t have, but at times have thought of ignoring it because it was getting rather heated. I’m glad I didn’t, but I do hope that now the rancour can be left behind because the substance was well worth the effort, even if the delivery left something to be desired on occasions. 🙂 Let’s keep talking, but gently. 

[facthunter]

It all shows why teaching low level flying is essential for all pilots. The ILLUSIONS you get near the ground have to be dealt with. Nev