Special Emphasis Stalls/Spin Awareness
- Thread starter Tailwind
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jrh
Well-Known Member
pfitmx15
Well-Known Member
I would teach the aerodynamics of both stalls and spins. Then I would teach him about common situations where the student can get into stalls and spins. Finally I would teach them the steps to stall and spin recovery. Also you might want to start the lesson off by talking about slow flight and how that will demonstrate to the student the control effectiveness and the charastics of the aircraft as it approaches a stall. this is how I taught it to the examiner a few weeks ago on my CFI initial and it went well.
Also to demonstrate to a student that a wing stalls at a given angle of attack and not airspeed, I drew a coefficient of lift graph versus angle of attack. On that graph you can add the drag curve and also draw where each wing will be in a spin to show that one wing is stalled more than the other. I also used the example of pulling to quickly out of a dive, and how the angle of attack is exceeded due to the flight path still going down but the aircraft trying to pull up to hard.
Matt
Also to demonstrate to a student that a wing stalls at a given angle of attack and not airspeed, I drew a coefficient of lift graph versus angle of attack. On that graph you can add the drag curve and also draw where each wing will be in a spin to show that one wing is stalled more than the other. I also used the example of pulling to quickly out of a dive, and how the angle of attack is exceeded due to the flight path still going down but the aircraft trying to pull up to hard.
Matt
Goldmember
Well-Known Member
Remember, always start with the BASICS as simple as you can and work your way up. If you start with the coeficient of lift and boundary layers and lift vectors you're going to get yourself all tangled up. After you've laid the groundwork, bring in the technical pieces one by one. Try going to asf.org and doing the essential aerodynamics course. It gives good examples and analogies.
nosehair
Well-Known Member
The first action of any "on-the-spot" teaching lesson is to find out the level of knowledge of the student. Start by asking what he knows about a stall or spin. If he says "nothing", ask how he came by the words. FIND OUT what he knows, and/or has misconceptions about, and start a base with simple basic blocks of information that come straight from the Airplane Flying Handbook. Not memorized canned blocks of information, but a knowledge, and interest, deep enough to find the unique words and phrases that make his light turn on.
That's all he wants.
:yeahthat: Except for the AFH *cringe*...For the FAA, by all means. After the FAA get yourself a real book on aerodynamics and learn it. :Aerodynamics for Naval Aviators" is one you will hear about here all the time.
I actually find this interesting, just in the reference alone. It is always referred to as stall/spin awareness. Yet if you don't stall you don't need to worry about a spin. If you are focused on awareness, I would spend most of the time on scenarios like you said.
Definitions:
Stall: Increasing the wings AOA beyond critical, most likely to occur from slow speed flight. The wing can no longer produce enough lift to keep the aircraft aloft. The correction is to pitch down, lowering the wings AOA.
Spin: Occurs when a wing is stalled but one wing is further stalled than the other.
Scenarios:
Fixation: Discuss various forms of fixation in the pattern that could lead to a pilot forgetting to fly the airplane and possibly getting into stalled flight.
Pitching for Altitude: Discuss the natural tendency for us to pull back to try and keep ourselves in the air, one common scenario is trying to stretch our glide path.
Base to Final: Cross controlled, this is important, skidding, not slipping, stall. Here is a scenario from one of my optional lessons, still under construction but you should be able to get the idea: (Note: They were, at one point or another, taught all of this in earlier lessons.)
Cross Controlled Stalls
Detailed Scenario: Here is a list of questions you should think about as your homework for this lesson. You will go through each of these questions during your brief today. This will help you understand what is actually happening in a stall and the causes for entering dangerous cross-controlled stalls.
Recall: The diagram from earlier lessons on an aircraft in a 60-degree bank turn and the resulting g-forces and increased stall speed.
General Questions: Assume a 60-degree bank.
General Questions: Assume a 60-degree bank.
Are there any G forces acting? If so how much?
Does this effect aircraft weight? (Note: The weight will remain unchanged, but does this change how heavy the aircraft “thinks” it is, think of what G forces do to you.)
Does this change our stall speed? If so, how much?
Does this increase our angle of attack?
Does this turn increase or decrease total drag? Why? (Include what type of drag you think increases or decreases.)
Does this effect aircraft weight? (Note: The weight will remain unchanged, but does this change how heavy the aircraft “thinks” it is, think of what G forces do to you.)
Does this change our stall speed? If so, how much?
Does this increase our angle of attack?
Does this turn increase or decrease total drag? Why? (Include what type of drag you think increases or decreases.)
Compare Wings: Assume a 60-degree bank.
Which wing is moving faster/slower or are they moving the same speed?
Which wing has more lift or are they equal?
Which wing has more drag or are they equal? Which kind(s) of drag is this?
Which wing has more lift or are they equal?
Which wing has more drag or are they equal? Which kind(s) of drag is this?
Compare Wings: Assume we are a little uncoordinated, using too much rudder, and are skidding in this turn. What will this change do with each of these:
Which wing is moving faster/slower or are they moving the same speed?
Which wing has more lift or are they equal?
Which wing has more drag or are they equal? Which kind(s) of drag is this?
Will this rudder input cause an increased overbanking tendency?
Which wing has more lift or are they equal?
Which wing has more drag or are they equal? Which kind(s) of drag is this?
Will this rudder input cause an increased overbanking tendency?
How will you correct for this overbanking tendency?
What effects will your correction have on:
Left wing vs. right wing AOA?
Will this have any negative effect on the rudder coordination? If yes, why.
Will this have any negative effect on the rudder coordination? If yes, why.
External Effect: If you recall from earlier lessons, when we encounter a gust or turbulence, the AOA is increased slightly and will ultimately result in the start of an unexpected wing drop in the direction opposite which you are already turning those ailerons:
What do you think your natural reaction (instinct) will be?
What would this reaction cause the aircraft to do? Explain what happens and why as best you can. (Hint: Go through sections iii, iv, and v again.)
Final Thoughts: Now that you have seen how this all piles up, what do you think the correct action is for a cross-controlled stall recovery and why?
Slipping: Slips are inherently a stable maneuver. Therefore, if you ever have to be in any form of cross control, you should ensure it is a slip. As you will see, it is nearly impossible to even get a violent stall.
Skidding: An unstable maneuver that was the focus of the scenario above and the homework for your lesson today. This type of cross-controlled stall should be avoided at all costs, as you will come to realize from the violence of the stall in flight today.
Performing: Start by entering either a slipping or skidding steep turn (>45), depending on which you are trying to demonstrate. Keep the aircraft from turning by using the ailerons in the opposite direction from the direction of the rudder. Finally, start bringing the nose up, continuing to increase the AOA until the aircraft stalls. In trainer aircraft, it may be necessary to pull back more abruptly to ensure the aircraft actually becomes stalled.
Slipping: Slips are inherently a stable maneuver. Therefore, if you ever have to be in any form of cross control, you should ensure it is a slip. As you will see, it is nearly impossible to even get a violent stall.
Skidding: An unstable maneuver that was the focus of the scenario above and the homework for your lesson today. This type of cross-controlled stall should be avoided at all costs, as you will come to realize from the violence of the stall in flight today.
Performing: Start by entering either a slipping or skidding steep turn (>45), depending on which you are trying to demonstrate. Keep the aircraft from turning by using the ailerons in the opposite direction from the direction of the rudder. Finally, start bringing the nose up, continuing to increase the AOA until the aircraft stalls. In trainer aircraft, it may be necessary to pull back more abruptly to ensure the aircraft actually becomes stalled.
Edit: Be sure you do this with a model airplane while answering the questions. The goal is to understand that the low wing is moving much slower and, due to aileron input, is at a higher AOA. So if the wing stalls the low wing would be further stalled then the high wing, the definition of a spin. It is made worse because the rudder is applied in the direction of the low wing, the direction the aircraft would begin to spin.