Spin Training

[Big Pistons Forever]

What an irresponsible git! Having fun in an airplane! Someone will be around shortly to collect your wings buddy-boy.

I guess I am just old fashioned because I think mastering control of the aircraft should be a perquisite to advanced manoevers.

Flying is truly fun when you know you can make the aircraft do Exactly what you want it to do..........

[Beefitarian]

The spiral dive is much worse for the reason you stated last page BPF, plus students under estimate the danger because most just think of it as a funny turn.

Flight school and rental aircraft should have G-meters that send a radio signal every time they exceed a limit.

[mcrit]

I guess I am just old fashioned because I think mastering control of the aircraft should be a perquisite to advanced manoevers.

Flying is truly fun when you know you can make the aircraft do Exactly what you want it to do..........

BPF, chill my friend. My comment wasn't a jab at you.

[Cat Driver]

I can understand the problems some here may have with solo spins.....

But seeing as this is a flight training forum and I asked a simple question why is there no comment?

Quote:
In straight and level flight with cruise power if we roll the airplane to a banked attitude say 30 degrees of bank with the elevator and rudder neutral and check the bank angle with aileron what will the next movement be? Assuming you do not move either elevator or rudder.

The above is a basic attitudes and movements question.

Was I teaching something that was wrong?

[Old Dog Flying]

BPF: Your story is exactly why we should be teaching full spins..so that the student can recognize the difference between a spin and a spiral and be able to know, and use, the recovery technique for both. Years ago at King City a C150 landed with the right side stabilizer bent down about 20* from just what you described..not knowing how to recover from the situation that he had put himself into.

[Old Dog Flying]

.: It all depends on how agressively the roll was carried out and in some cases the aircraft involved but if the roll was agressive then the nose would momentarily swing away from the direction of the roll due to adverse yaw. It would then turn in the direction of the roll..but what the hell I haven't instructed in 10 years

[pdw]

what will the next movement be? Assuming you do not move either elevator or rudder.

Pitches down with increased turning towards the direction of the 30 degrees of bank, when checking it with aileron.

[Cat Driver]

Pitches down with increased turning towards the direction of the 30 degrees of bank, when checking it with aileron.

We are getting close, but not quite there yet.....

......once again in the situation I described what movement will occur?

Maybe instructors do not read this forum?

[PilotDAR]

Flight school and rental aircraft should have G-meters

Haha! One of my client's Cessnas, which works for a living, has twice in the last year been damaged by poor piloting. Each repair far exceeded the annual salary of the pilot. I suggested to my client that he secretly install a G meter, which to pilot cannot see or locate. He did, and the recorded results have been interesting!

Yes, training aircraft should be equipped with a G meter.

[Cat Driver]

Yes, training aircraft should be equipped with a G meter.

What would be even better would be an IQ meter.

[photofly]

Assuming you do not move either elevator or rudder.

Assuming you fix the elevator in the trim position for the (previous) straight and level flight, rudder centred and ailerons in trail:

The aircraft will pitch down and start to descend. It will also start a sideslip towards and a roll away from the low wing because of slip-roll coupling, so the bank angle will start to decrease as the altitude unwinds. The speed will increase and the nose will start to pitch up as part of a phugoid oscillation.

Minimum bank will be reached as the aircraft starts to climb again, at which point the aircraft will roll towards the low wing as the airspeed decreases. The nose will continue to rise and the aircraft will complete its climb at some altitude slightly lower than where it started. Whether the bank angle is greater or lesser than the original 30 degrees depends on whether the slip-roll coupling is stronger than the unstable roll mode, which depends on aircraft design, the original airspeed etc. The cycle then begins again.

Assuming there is enough roll and pitch damping for the aircraft to reach a steady state, it will (eventually) end up in a descending spiral dive.

[pdw]

Check of that bank angle only with aileron produces skidding, a sideslip outwards.

[Cat Driver]

In straight and level flight with cruise power if we roll the airplane to a banked attitude say 30 degrees of bank with the elevator and rudder neutral and check the bank angle with aileron what will the next movement be? Assuming you do not move either elevator or rudder.

The above is a question that relates to how we taught attitudes and movements many decades ago, it is part of the demonstration of effects of control and aircraft movements.

The question is specific.......as you check the angle of bank with ailerons what will the next movement of the airplane be?

The question is not meant to go beyond that ......checking roll will result in another movement taking place in a normally configured light training airplane such as a Cessna.

[photofly]

as you check the angle of bank with ailerons

You don't check an angle - you can check (null) the roll rate - is that what you mean?

If you apply aileron to null the roll rate you might expect some (a little) yaw into the low wing, while the ailerons are deflected.

[Cat Driver]

You don't check an angle - you can check (null) the roll rate - is that what you mean?

Yes. exactly. Stop the roll rate ......checking as in maintaining the last angle of bank.

If you apply aileron to null the roll rate you might expect some (a little) yaw into the low wing, while the ailerons are deflected.

That was the answer I was looking for, the stopping of the roll rate will produce a yawing movement

Here is how we were taught to teach attitudes and movements. The wording went like this.

" From straight and level flight we roll the airplane to the banked attitude with aileron note with left aileron the left wing will go down, now if we stop the increasing bank angle with aileron the nose will move towards the low wing, this movement we see is the yawing movement and was produced as the airplane sideslipped towards the low wing and weathervaned around the vertical axis due to the effect of the tailplane and fuselage. "

As far as I know the above is still what will happen today just like fifty years ago.

[CpnCrunch]

I guess this issue is a bit personal because I once had a student ask me to look at the horizontal stab of the sircraft we were about to take out because it " did not look right " . When I examined the underside you could sees a small diagonal crease. I called the engineer over and we had a look in side with a small mirror.

The plane I have been recently flying had a loose horizontal stab and vertical stab for years with nobody noticing. Eventually a new pilot did a thorough walkaround and asked "why do the tail fin and horizontab stab wobble?" The AME found that the bolts on both were loose. One pilot had been flying it for years like that and thought it was just meant to be like that. Probably the AME should have noticed it sooner at the very least.

Also, whenever I sold my plane we discovered that there was a rib missing in the horizontal stab. It probably wouldn't have been a problem, although I wouldn't have wanted to do aerobatics with it like that. That was actually discovered by the buyer's instructor just poking the airframe with his hand (and missed by a number of previous AMEs, including the very expensive AMO at YBW that likes doing $10k annuals without warning you).

Point is: do you really want to put a high load on a 40 year old plane if you're not absolutely certain how structurally sound it is? Even doing a 60 degree turn puts a lot of strain on the airframe.

[pdw]

So, no skid at all induced by that action, ... just a reduction of slip?

[photofly]

Some yaw occurs when you have a roll acceleration, typically when the ailerons are deflected to change the roll rate. (For a normal turn that gives you adverse yaw as you increase the roll rate into a turn, and proverse yaw as you null the roll rate as you reach the bank angle you want.) There's also yaw into the low wing because of the side-slip. But they're two different effects.

On a high-wing cessna trainer you don't get much yaw on aileron deflection because they're a) differential and b) Frise type. If you do want to demonstrate that effect, do it at low airspeed.

[Cat Driver]

There's also yaw into the low wing because of the side-slip. But they're two different effects.

Correct, and this effect is a normal action that occurs when performing a turn in an airplane.....yaw produced by stopping the roll.

If you really want to see adverse yaw caused by aileron deflection you should fly a PBY.

The ailerons are the size of a cessna 150's wing and the adverse yaw is truly stunning if you aggressively use the ailerons.

[triplese7en]

Also the Fleet Canuck was in my opinion the best basic trainer you could ask for.

I'm lucky to have access to a pristine condition Canuck for regular flights. It is a great plane to learn in. It's fun to fly it without touching the stick (using elevator trim and rudder) - all the way to ~100' AGL. It's lovely to fly!

Recover
with opposite rudder and by relaxing back pressure
on the stick or control column, to reduce the AOA.

I would not do that and I would recommend against using uncoordinated rudder in a stall to any pilot. There are a number of reasons why you shouldn't use rudder to "pick up a wing" in a stall - PilotDAR highlighted the one about putting the aircraft into a yawed condition while it is stalled. When you're stalled and you have yaw, that tends to produce a spin. Emphasis should be on recovering from the stall promptly which can ONLY be done by reducing the AoA. Since the pitch control is the most direct way of changing the AoA it is important to reduce the pitch to recover from the stall. Altitude loss can be minimized by adding full power. As for the dropped wing - forget about it until you're not stalled anymore (i.e., you've completed the first step and reduced the pitch attitude). Once you're not stalled then you should use coordinated use of the controls to roll the airplane to level flight before pulling out of the dive.

Here are a couple quotes from FAA documents on the matter:

“Straight and level flight should be established with full coordinated use of the controls.” - Advisory Circular 61-67C – Stall and Spin Awareness Training

“…straight-and-level flight should be regained with coordinated use of all controls.” - Airplane Flying Handbook, page 4-5 and page 4-6, 2004

These two paragraphs from the FAA Airplane Flying Handbook, under the heading “Use of Aileron/Rudder in Stall Recovery”, summarize it well: “When the airplane is in a stalled condition, the wingtips continue to provide some degree of lift, and the ailerons still have some control effect. During recovery from a stall, the return of lift begins at the tips and progresses toward the roots. Thus, the ailerons can be used to level the wings.”, “Even though excessive aileron pressure may have been applied, a spin will not occur if directional (yaw) control is maintained by timely application of coordinated rudder pressure. Therefore, it is important that the rudder be used properly during both the entry and the recovery from a stall. The primary use of the rudder in stall recoveries is to counteract any tendency of the aircraft to yaw or slip. The correct recovery technique would be to decrease the pitch attitude by applying forward-elevator pressure to break the stall, advancing the throttle to increase airspeed, and simultaneously maintaining directional control with coordinated use of the aileron and rudder.”

Most stalls in the C152 require you to add rudder towards the dropped wing to coordinate the airplane. This is because since the airplane is stalled and banked, it enters a slip. If the left wing drops in the stall, the airplane enters a slight slip to the left which requires a very slight tap of left rudder as you apply right aileron to roll wings level. I usually don't mention this to students as I don't want them focusing at all on the rudder when teaching stall training. They've got in their mind that when they want to roll the airplane they use rudder to coordinate the roll and that's what I want stuck in their mind during initial stall training.

In summary: Do not apply uncoordinated rudder in a stall recovery procedure.

[photofly]

Interesting. Two very different schools on how to recover from a stall/wing-drop.

There are a number of reasons why you shouldn't use rudder to "pick up a wing" in a stall - PilotDAR highlighted the one about putting the aircraft into a yawed condition while it is stalled. When you're stalled and you have yaw, that tends to produce a spin.

I don't buy that one: the uncoordinated use of the rudder prevents a spin. Picking up a wing with the rudder is exactly the same rudder input you use in spin-recovery. There's no prohibition on uncoordinated rudder usage when recovering from a spin, clearly.

What are the other reasons?

[Old Dog Flying]

Just try using aileron to pick up a dropped wing in a Tomahawk and then use the same arguement...if you are still in one piece. At or near the stall and a wing drops..USE RUDDER TO PICK IT UP..not aileron. The use of aileron at the onset of a spin will only accelerate the spin.

That "pristine" Canuck may not be pristine for long with that logic.

Shortly after the PA-38 was introduced in the fall of 1978 there were 5 stall spin accidents, 4 in the US and 1 at YXD. Four of the accidents were fatal, the other, an instructor and student went through the roof of a barn and it was the strength of the aircraft that prevented another fatal when it hung up in the rafters of the very large barn. And in this case the instructor was teaching slow flight at 1200' AgL when a wing went down and he ttried using aileron to pick it up.

...you really should not pi$# these kids off but at our age GO FOR IT!

[Cat Driver]

The rudder will produce, control, and prevent yaw and far to often is the least used and understood airplane flight control.

Rudder effectiness will vary from one airplane design to another and therefore each airplane should be flown based on the design effectivness of the controls.

[triplese7en]

photofly - I do agree with what you said. However, if the student is taught that they should apply rudder right away so that the wing doesn't drop, what happens when the wing very gently goes to the left and the student aggressively applies right rudder? It can easily go into a spin from that point. Why would we get the student to focus on applying rudder to pick up a wing that's dropped during a stall when the main thing we should be focusing on is getting out of the stall?! This is one reason why I don't teach the falling leaf stall and why I think it's dangerous. In the falling leaf stall the aircraft is stalled - clearly. Why are we teaching students post-stall maneuvering when the airplane is clearly not designed for that? Only some fighters have post-stall maneuvering capability. A Cessna does not. So in this stall you're getting them to 'dance' on the rudders so that they keep the airplane upright and this is somehow supposed to get the student better at applying coordinated rudder pressure when not in a stalled condition. How backwards is that? What CS said to do with regard to banking back and forth at a low speed and 20 degrees flap is excellent for that. Falling leaf stall is not, at all! Colgan Air Flight 3407 - airplane is stalled and Captain is 'dancing' on the rudders instead of pitching down to recover from the stall.

Other reasons: At the point of stall the air flowing over the wing is extremely turbulent and, therefore, not producing effective lift. The best way to produce lift is to have smooth airflow that flows perpendicular to the leading edge of the wing. Any spanwise flow is not conducive to lift. The large amount of spanwise flow on swept wing aircraft is part of the reason why they can go so fast, but also a reason why they have poor stall characteristics! If rudder, opposite to the wing drop, is used during the stall recovery it puts the aircraft into a slip, which progresses towards a skid. The slip, being used to decrease the lift and increase the drag on the wing for the purpose of losing altitude, goes against the goal of recovering with minimum altitude loss.

Imagine the aircraft has a wing drop to the left at the point of stall and the recovery procedure is initiated when the angle of bank is at 45 degrees. At this point, the elevator is effectively 50% elevator and 50% rudder. When pitching down you accomplish two things: reducing the angle of attack and reducing the yawing moment. Approximately ¼ - ½ second after initiating a pitch down movement, full aileron control and coordinated rudder can be used to bring the wings to level. Even at the point of stall, many modern general aviation aircraft have sufficient roll control due to the washout of the wing and other design features. If aileron control is applied at the stall in these aircraft, they will most likely roll in the direction applied, the opposite of what is taught will happen. It is true, mostly on high performance aircraft, that it’s possible to induce a spin by using aileron at the point of stall. I'd like to make it crystal clear that I do not teach students to use aileron and I ensure that they do not use aileron in stall recovery.

The other part to that example is what applying rudder does to the stall recovery. At 45 degrees angle of bank the rudder, like the elevator is equally split. It will provide 50% rudder and 50% elevator control. If you applied opposite rudder (right rudder in this case) the aircraft would reduce its yawing tendency and put it into a slip, but it would also increase the pitch of the aircraft, something that is opposite to what we want!

EDIT: That last sentence about rudder increasing the pitch of the aircraft isn't correct. Rudder is always yaw and elevator always pitch. However, I believe it will increase the AoA (or prevent the AoA from decreasing) as you are pointing the nose of the airplane away from the direction in which it is travelling, something that is opposite to what we want!

[triplese7en]

Just try using aileron to pick up a dropped wing in a Tomahawk and then use the same arguement...if you are still in one piece. At or near the stall and a wing drops..USE RUDDER TO PICK IT UP..not aileron. The use of aileron at the onset of a spin will only accelerate the spin.

Old dog - You completely misunderstood me. I never said to use aileron while stalled and I would ensure that a student never did use aileron either. What I'm saying is that when you are stalled, do not use aileron or rudder to 'pick up a wing'.

Rudder effectiness will vary from one airplane design to another and therefore each airplane should be flown based on the design effectivness of the controls.

Cat - Agreed. I don't think that changes what I'm saying with regard to using "coordinated" controls. One airplane might require more rudder than the next to coordinate with aileron application.