power off stall

i am in phase 1. I can very gently pull the stick all the way back with the power at idle and it will buffet and airspeed is about 50kts. the nose does not drop. i can get it to drop if i pull back quick. is this normal? my cg is in specs but at the forward edge. i am at about 1400lbs.

Yes, the buffet is pre-stall. It will just buffet on down to the ground if you keep the stick in the sweet spot. The stall happens when you go past (move the stick back farther) the sweet spot and then the nose will drop.

Just wait till you try power-ON stalls. That's where it gets interesting ...

In order to calibrate my Dynon AOA indicator, I had to do a series of stalls in various configurations. I had already done power off stalls both clean and dirty prior to my first landings.

Without flaps and full power, I kept pulling back ... pulling back ... airspeed drops below 45 knots ... 42 knots ... 40 knots ...

Finally, at about 39 knots I felt the stick shudder and I bailed. I didn't have the stones to let a full stall develop.

Then came the power-on stall with flaps. Same thing ... kept pulling back ... back ... back ... airspeed falling through 40 knots ... 38 ... 36 ... 34 ...

I felt like Sean Tucker, hanging on the prop when, at 33 knots, the plane gave an almost imperceptible shudder. Lowered the nose, raised the flaps and checked my shorts. Whew!

I know that I'm gonna have to go through that exercise again someday. I doubt that I calibrated it properly.

What about "pattern" stalls?

Formal testing is good, of course. The one kind of stall I actually worry about, though, is the turn from base to final with a short or soft field. Would anyone like to describe what that stall is like?

hevansrv7a said:

Formal testing is good, of course. The one kind of stall I actually worry about, though, is the turn from base to final with a short or soft field. Would anyone like to describe what that stall is like?

Click to expand...

It is breathtaking and instant. I did some with a CFI while getting transition training. It happens right NOW, very little if any warning, and you will find yourself practically upside down before you know it.

It was a very eye-opening experience, one that is burned into my memory every time I turn base to final.

A final note. I was pleased to see how quick I was able to "right the ship" and fly out of the stall. That in no way, however, negates the need to treat the "coffin corner" with respect.

Go out and practice accelerated stalls at altitude. You should not fear the unknown. You should eliminate it. (IMHO)

hevansrv7a said:

Formal testing is good, of course. The one kind of stall I actually worry about, though, is the turn from base to final with a short or soft field. Would anyone like to describe what that stall is like?

Click to expand...

i've done around 30 of these ... at 8000' AGL

first my best recovery is 1900 feet
my worst recovery is 2100 feet

either way if you are in the pattern, you are dead.

dan said:

Go out and practice accelerated stalls at altitude. You should not fear the unknown. You should eliminate it. (IMHO)

Click to expand...

Thanks Dan, I've been biting my tongue all afternoon. And not just once during phase I. Refresh your memory periodically. This applies throughout a large swath of flight operations and failure modes.

n468ac said:

i've done around 30 of these ... at 8000' AGL

first my best recovery is 1900 feet
my worst recovery is 2100 feet

Click to expand...

You must be talking spins, not accelerated stalls. Or did you split-S out of something to have lost that much altitude?

You ought to be able to recover from an accelerated stall darn near immediately by simply unloading.

stalls in pattern

What is the logic for flying the pattern and risks of stalls vs straight in landing using vasi lights or visual reference on windshield? Do low time pilots have difficulty in gauging the approach?
Is it just the way it has always been, or proven lower accident rate?

burgundyja said:

i am in phase 1. I can very gently pull the stick all the way back with the power at idle and it will buffet and airspeed is about 50kts. the nose does not drop. i can get it to drop if i pull back quick. is this normal? my cg is in specs but at the forward edge. i am at about 1400lbs.

Click to expand...

Stall characteristics are are very much effected by C.G. position.
This is even more pronounced in a tandem seating aircraft because their is a much bigger shift in C.G. just from seating someone in the other seat. so to compensate the design is such that when flying solo the C.G. typically is quite a bit fwd..

Continue to learn the airplane. Phase 1 is for your experience as much as it is for testing the airplane. Use the test phase as it was meant to be used... slowly start adding ballast to increase weight and vary the C.G. towards the aft end of the limit.

It is far to common that RV owners experience their first aft C.G. flight when they make the first trip with a passenger full fuel and baggage which translates to an aft C.G. after burning off a large portion of the fuel (except an RV-12). A conscientious rv pilot will be very familiar with the airplanes handling in this condition before they have a passenger on board.

Keep testing (and learning). It sounds like you are on the right track to a methodical test program.

skidoc said:

What is the logic for flying the pattern and risks of stalls vs straight in landing using vasi lights or visual reference on windshield? Do low time pilots have difficulty in gauging the approach?
Is it just the way it has always been, or proven lower accident rate?

Click to expand...

If your question is why do we fly a downwind, base, and final, one answer is so we can stay close to the airport in case the engine fails. Another answer is at "uncontrolled" airports (sans tower), it is a good way to find other traffic and sequence yourself into the pattern. Also, if doing touch and goes for practice, there has to be a way to get from the upwind to final.

A straight-in approach seems less safe to me, as I am low to the ground too far from the airport. Also difficult for others in the pattern to see me.

Why do you perceive a greater risk for stalls when flying a pattern?

Power on stalls take a huge amount of right rudder..

...in order to stall straight ahead. From what I've observed, few guys hold enough right rudder as the airspeed slows and I watch the nose yawing left. To the airplane, it equates to pushing left pedal and the airplane often snaps over the top to a near inverted position.

The technique to solve this problem is to look left/right, left/right and keep the same amount of horizon above each wingtip. Since you can't see over the nose, it does no good to stare, like a deer in the headlights, into the blue sky ahead. At the same time, if your left wing appears to be "backing up", then you need to stop that by adding more right rudder....both wings should appear stationary but tilted up as you get nearer the stall.

Regards,

what i am wondering is if it is normal that with full aft stick you cant stall the aircraft?

burgundyja said:

what i am wondering is if it is normal that with full aft stick you cant stall the aircraft?

Click to expand...

You most definetely stall an aircraft with the stick full aft.

In fact, that is how the aircraft is usually stalled during power on and power off stall practice. And not to sound scary, but in most cases where there is an accident involving a stalled condition and the investigators inspect the condition of the crashed plane, the stick is found in the fully aft position.

So, the short answer is that an aircraft can be stalled in any stick position.

Not being able to stall

Mike

Without flying in the aircraft with you, it would be difficult for me to say weather the aircraft was stalled or not. I have flown a couple of airplanes where there was not enough tail authority to stall the wings. Basically, with full aft stick the tail stalls before the wings do On other aircraft, I've had full aft stick and the wings were indeed fully stalled however, the aircraft was balanced so well that instead of one wing dropping off, it would stay upright with a high rate of descent. I would check your elevator travel distances and make sure you are able to get full rated throw. You should be able to program enough angle of attack to stall the wings. Are you doing this with flaps, power on/off ??

rvbuilder2002 said:

Stall characteristics are are very much effected by C.G. position.

Click to expand...

Yes, and in particular, spin characteristics are affected by CG. In order to get our ASK21 gliders to spin reliably for students, we bolt weights on to the tail to get the CG aft. Looks freaky, but it works darn well. The ship flies wonderfully with the CG aft.



Photo is from another ship (thanks be to wikipedia), but we do the same thing, except it normally only takes two of us.

TODR

dan said:

You must be talking spins, not accelerated stalls. Or did you split-S out of something to have lost that much altitude?

You ought to be able to recover from an accelerated stall darn near immediately by simply unloading.

Click to expand...

Unless he's referring to the skidded turn stall?? Around here we regularly do both the approach turn stall (ATS), which done correctly results in only 50' or so alt loss. The other is the skidded turn stall (STS) which you definitely depart controlled flight and lose around 1000'. About the only difference between the two is with the ATS we have the ball centered and with the STS we purposely have the ball completely displaced. Both cases we start with 30 AOB, 12-15 degrees nose up, power at idle. In the pattern the ATS should definitely be recoverable while the STS in the pattern would definitely be 100% fatal.

N8RV said:

Just wait till you try power-ON stalls. That's where it gets interesting ...

In order to calibrate my Dynon AOA indicator, I had to do a series of stalls in various configurations. I had already done power off stalls both clean and dirty prior to my first landings.

Without flaps and full power, I kept pulling back ... pulling back ... airspeed drops below 45 knots ... 42 knots ... 40 knots ...

Finally, at about 39 knots I felt the stick shudder and I bailed. I didn't have the stones to let a full stall develop.

Then came the power-on stall with flaps. Same thing ... kept pulling back ... back ... back ... airspeed falling through 40 knots ... 38 ... 36 ... 34 ...

I felt like Sean Tucker, hanging on the prop when, at 33 knots, the plane gave an almost imperceptible shudder. Lowered the nose, raised the flaps and checked my shorts. Whew!

I know that I'm gonna have to go through that exercise again someday. I doubt that I calibrated it properly.

Click to expand...

Don,

I've been flying the LRI indicator for several years. Several months ago I connected the Dynon AOA port to the LRI probe and have had good success in running both the LRI and Dynon AOA indicators off the same probe. I like having the Dynon audio alarm.

When my plane was in Phase 1 ten years ago I flew a power-on stall, and the maneuver was so aggressive I decided there was no need to repeat that exercise. Consequently, I knew the departure stall would not be a part of calibrating the Dynon AOA indicator. I flew just the flaps-up part of the Dynon routine and it resulted in the Dynon indicator matching the LRI which I knew was accurate after many years of use.

So, you will most likely have a good Dynon AOA even if you don't do the power-on stall sequence. Since I don't have aerobatic training the power-on stall is just too sporty for me since I don't want to spin the RV-6.

burgundyja said:

what i am wondering is if it is normal that with full aft stick you cant stall the aircraft?

Click to expand...

Which prop do you have?

When I switched from my two-blade Hartzell to the three-blade MT, I noted that the additional discing drag from the MT seemed to reduce the nose up pitch authority with idle power. At forward CG, I've got marginal up-elevator to stall the wing with full flap and idle power. Sometimes I'll get a clean nose drop, other times just a lot of buffet. Very slow decelerations to the stall will have lower peak AOA, and there is a lower probability I'll get a clean nose drop. More brisk decelerations have a higher peak AOA, and I'll get a nose drop every time.

The low pitch stop on my MT is set a bit finer than it really needs to be. I'm going to look into what is required to move it a bit more coarse. This would reduce the discing drag, and would probably yield a bit more nose up pitch authority at idle power.

skidoc said:

What is the logic for flying the pattern and risks of stalls vs straight in landing using vasi lights or visual reference on windshield? Do low time pilots have difficulty in gauging the approach?
Is it just the way it has always been, or proven lower accident rate?

Click to expand...

Steven,

The compelling logic of a traffic pattern around any airport is to avoid mid air collisions (and sometimes a need to lessen noise). That's not to say every approach has to be by the book with regard to pattern entry, downwind, base and final; it frequently is not at a controlled airport. But basically it provides for some order with regard to the flow of traffic absent a controller running the show. A call 8 miles out announcing the intent to make a straight in approach is perfectly legitimate - traffic permitting - but a reason to do so can not be to avoid a stall in the pattern. To announce or even think, "I am making a straight in approach because I am not up to flying a traffic pattern without the risk of stalling the airplane" is totally unacceptable. There is NO risk of a stall anywhere in flight for a properly trained and disciplined pilot and especially while flying a normal traffic pattern.

There is a risk for those who are simply unqualified or who fly with little discipline. By that I mean, every airplane has an operating margin of safety and the pilot must know what that margin is, be aware of it always, and not become complacent with regard to it.

The only reason we do a stall series in Phase One is to become aware of when flight ends, uncontrolled flight begins, what the symptoms are leading up to that event, and finally how to recover from it - should it occur due to ignorance or complacency. A properly trained pilot with a sense of discipline will never experience such an event inadvertently.

OK. For guys just starting their flying experience, how do you avoid stalling in the traffic pattern?

1. Know when your airplane will quit flying. That covers a lot of territory but basically knowing the one G environment is a start. It doesn't matter if the airplane is straight and level or in a 60 degree bank descending turn, the one G stall speed is the same. It's when the stick is hauled back to correct for over shooting final, or to maintain altitude, that the G load goes up and so does the stall speed. Every pilot must understand this phenomenon and if it did not sink in during primary training, go back to the basics with an instructor until it is up front in your brain and clearly understood. If you do not understand it now, ground yourself until you do.

2. Fly the traffic pattern at no less than stall speed plus 30% until on short final with the runway made. It is perfectly safe to reduce that speed to 15-20% the last 100' of descent with a short field approach and landing. Do not ever get into a situation where the airplane has to be "yanked and banked" any where in the traffic pattern. Keep it smooth, on speed, and you will never get into trouble. If the guy in front of you is too close and slow, break it out and start over.

This post, I know, sounds preachy but the basics of it will keep you alive. Safe flight demands that you be aware of what airspeed is required at the moment. If that is not a primary habit pattern on each and every flight, think about making it just that.

Good post David!

I am a low time pilot and although none of that information was new to me, I still like to read stuff like that from guys who are more experienced.

Crossbow said:

You most definetely stall an aircraft with the stick full aft.

In fact, that is how the aircraft is usually stalled during power on and power off stall practice. And not to sound scary, but in most cases where there is an accident involving a stalled condition and the investigators inspect the condition of the crashed plane, the stick is found in the fully aft position.

So, the short answer is that an aircraft can be stalled in any stick position.

Click to expand...

I do not believe your assertion about stick position is correct. I don't think an aircraft will exceed stall angle-of-attack (AoA) with the stick in the middle.

Try this test: Start at straight and level cruise, trimmed. Then use two hands, and hold the stick in that position, and close the throttle. I believe that the plane will only begin a descent, and will never stall.

Many pilots confuse stick force with stick position. In fact, the plane will always stall with the same stick position. I routinely demonstrate this during Flight Reviews (formerly BFR's).

A one-G level stall usually occurs with the stick a bit forward of fully aft, unless there is a severe forward CG. The stick force is very light. In an accelerated stall, the stall occurs with the same stick position, but it requires more force on the stick.

Stick position is directly related to angle of attack. (I'm sure someone will correct me if I'm wrong. Any test pilots out there.........?)

Stalls and stick position

burgundyja said:

what i am wondering is if it is normal that with full aft stick you cant stall the aircraft?

Click to expand...

It is normal, especially when you approach the stall slowly. You see, a wing stalls when you exceed the critical angle of attack. With a forward CG, all your elevator authority is needed to overcome that condition. It's harder to get to the critical angle of attack (you just don't have enough elevator authority). The forward limit of CG is that condition that allows you just enough pitch authority to flare. The aft limit establishes the longitudinal (or pitch) stability of the aircraft (both static and dynamic).

Add some weight in the rear and you will see your condition change. Generally speaking, the more aft the CG the earlier the onset (with respect to stick force and position) and the more dramatic the stall.

Your original question sparked comments on turns to final and straight in approaches... so I pontificate here:

Unfortunately, most pilots get there training in a C152 or C172 (no pax in the bax). The Cessna 152 can be brought slowly into a stall, held full yoke aft and flown slowly to (towards) the ground like that using rudder to keep the wings level. A C172 is similarly benign, but changes when you start adding weight in the back. It can get more difficult to recover from a stall, but not overly difficult.

I encourage all my students to explore the limits of the envelope of their airplane. This is something I sometimes do at flight review time. Many are timid, and that's okay, but it's better to experience the unusual at safe altitude then when close to the ground.

I recall that power off stalls (approach to landing stalls) and power on stalls (takeoff and departure stalls) didn't make much sense to me as a student pilot, other than to demonstrate you could do them. Now, when I teach, I use real world scenarios: (1) You are taking off from a "short field at a high density altitude airport. Power is limited. There is a tree at the end. You keep raising the nose to get over it. Doesn't look to be enough....now you start a slow turn to miss it... but you get the nose too high and forget about right rudder (coordinated flight)". You can guess what comes next.

The same thing on approach to landing. (2) You get too slow (nose too high), rush that turn to final, kick a little left rudder to swing the nose around and... voila, you are a test pilot in uncoordinated flight entering a stall at low altitude.

I recommend you seek and experience all these scenarios at altitude with a competent instructor. If you understand what happens and why, what the limits are of your airplane and how it talks to you before it bites you, you'll be a better pilot.

Don

this is almost true

Center of gravity does affect the stick position for stall. As you move c.g. back, the stick position for stall will move forward.

The very first question on the thread - the answer is yes, it is common for the airplane to not be able to stall with the stick all the way back if you are at fwd c.g. limit.

It is possible to get the airplane to stall with the stick in the middle. What you do is put the c.g. at the airplane aerodynamic center ( true neutral point). This point is WAY behind the aft c.g. limit, probably about 92". ( aft c.g. limit is 86.8")
At that point, the airplane pitch moment is independent of angle of attack. So it will trim at any angle of attack with the same stick position, and that position will be very close to the middle.

PCHunt said:

I do not believe your assertion about stick position is correct. I don't think an aircraft will exceed stall angle-of-attack (AoA) with the stick in the middle.

Try this test: Start at straight and level cruise, trimmed. Then use two hands, and hold the stick in that position, and close the throttle. I believe that the plane will only begin a descent, and will never stall.

Many pilots confuse stick force with stick position. In fact, the plane will always stall with the same stick position. I routinely demonstrate this during Flight Reviews (formerly BFR's).

A one-G level stall usually occurs with the stick a bit forward of fully aft, unless there is a severe forward CG. The stick force is very light. In an accelerated stall, the stall occurs with the same stick position, but it requires more force on the stick.

Stick position is directly related to angle of attack. (I'm sure someone will correct me if I'm wrong. Any test pilots out there.........?)

Click to expand...

Refining the statement

So if I say: "For a given CG, the plane will always stall at the same stick position, would that be correct? (Ignoring the extreme aft CG example.)

CG position definitely affects stick position for the stall.

Stick Position

PCHunt said:

So if I say: "For a given CG, the plane will always stall at the same stick position, would that be correct? (Ignoring the extreme aft CG example.)

CG position definitely affects stick position for the stall.

Click to expand...

I think it would be more accurate to say "The aircraft will stall at the same (critical) Angle of Attack." How you get to that critical angle of attack is a function of weight, cg location, power application, etc.

Angle of attack

definitely. You can stall the airplane (accelerated) with it pointed straight down at the ground. You just have to pull hard enough for the airspeed . In my plane, with a 4G pull the plane will stall at 120 mph indicated whether level, banked or pointed straight down.

stalls too be avoided?

Sam,
I'm very interested in this topic.
when out with an instructor in my new-to-me -9a, he did a full power-on stall and I'm guessing, when the elevator stalled, the aircraft pitched forward violently beyond vertical, which resulted in about 1000' loss of altitude.
Is this what you are referring to?
I do not plan to 'practice' this manuever without a safety pilot, but this condition sounds like the typical departure stall, where one is trying to outclimb terrain in a heavily loaded, hot, high,condition......so it bears study!
If the elevator did NOT stall, you'd have the wing break...or mush, which to me would be desirable to this near-Lomcevak thing!
I'm considering VG's under the elevator for this reason.

I did not do any 'Phase 1' or 2 or... so evidently new owners should, if only to address some of these 'characteristics'. ( dare not call them anythign else here!)

...comments?

flyboy1963 said:

Sam,
I'm very interested in this topic.
when out with an instructor in my new-to-me -9a, he did a full power-on stall and I'm guessing, when the elevator stalled, the aircraft pitched forward violently beyond vertical, which resulted in about 1000' loss of altitude.
Is this what you are referring to?
I do not plan to 'practice' this manuever without a safety pilot, but this condition sounds like the typical departure stall, where one is trying to outclimb terrain in a heavily loaded, hot, high,condition......so it bears study!
If the elevator did NOT stall, you'd have the wing break...or mush, which to me would be desirable to this near-Lomcevak thing!
I'm considering VG's under the elevator for this reason.

I did not do any 'Phase 1' or 2 or... so evidently new owners should, if only to address some of these 'characteristics'. ( dare not call them anythign else here!)

...comments?

Click to expand...

I am not encouraging anyone to "avoid" complete testing of their RV. My post was just a recollection of my experience with full power departure stalls in my RV-6. Other aircraft may behave differently from mine due to being a different model (RV-9A vs RV6, etc), different CG, different engine/prop, and vastly different pilot experience.

I would not describe a full power departure stall in my airplane as "typical" anything! I can't imagine a pilot boneheaded enough to unintentionally fly the plane into the extreme nose-up attitude of a power-on stall.......unless he was hopelessly boneheaded........

I don't think VG's are necessary on any RV (the RV-8 wing root strakes might be an exception) since the plane as designed has huge safety margins. Learn to fly your RV-9A within its designed envelope, stay proficient, and the plane will treat you well.

I am in phase 1 with my -8. Approaching a stall with my normal forward solo cg is comical...the ship shakes and bucks. She gives you every chance to save yourself. Loaded with ballast towards aft cg, she is not so benign...
On another note, I am enjoying my AOA system.

flyboy1963 said:

Sam,
I'm very interested in this topic.
when out with an instructor in my new-to-me -9a, he did a full power-on stall and I'm guessing, when the elevator stalled, the aircraft pitched forward violently beyond vertical, which resulted in about 1000' loss of altitude.
Is this what you are referring to?
SNIP
If the elevator did NOT stall, you'd have the wing break...or mush, which to me would be desirable to this near-Lomcevak thing!

Click to expand...

Perry,

Your elevator did not stall, the wing did. What most often occurs during a power on stall is that due to a little bit (or alot) uncoordinated flight ( ball not centered), one wing will stall before the other. It then drops off precipitously and you have a spin entry condition. It looks like the nose was pointed straight down and may very well have been for a while.

I like to work my students up to such things by beginning with the power very low and gradually increasing the power. If you see my earlier post on scenario based training, you'll see that a low power setting (19-20" manifold or 1900 to 2000 rpm) simulates departing a high density altitude airport.

Not quite so scary that way. I recall my student days, trying to get that little Cessna 152 to do a takeoff and departure stall. It didn't want to cooperate, so I got a bit aggressive. I must have kicked rudder the wrong way because before I knew it, I was upside down. Of course I recovered successfully but I sure wished I had had spin training prior to that. So I would seek out an instructor and do a little spin training in an aircraft certified for that (a C152 or C172 will do fine).

Don

stall

Don,
appreciate your feedback. My only comment is the I'm 99% sure the ball was centred, and the 'break' was dead straight ahead, not a wing drop.
I did a lot of spins in the C152 and Piper Cherokee back in my training, and never experienced anything as violent as this...as you state, hard to get a 'good' spin going in these trainers.

of course I was 25 years younger too!

PCHunt said:

I do not believe your assertion about stick position is correct. I don't think an aircraft will exceed stall angle-of-attack (AoA) with the stick in the middle.

Try this test: Start at straight and level cruise, trimmed. Then use two hands, and hold the stick in that position, and close the throttle. I believe that the plane will only begin a descent, and will never stall.

Many pilots confuse stick force with stick position. In fact, the plane will always stall with the same stick position. I routinely demonstrate this during Flight Reviews (formerly BFR's).

A one-G level stall usually occurs with the stick a bit forward of fully aft, unless there is a severe forward CG. The stick force is very light. In an accelerated stall, the stall occurs with the same stick position, but it requires more force on the stick.

Stick position is directly related to angle of attack. (I'm sure someone will correct me if I'm wrong. Any test pilots out there.........?)

Click to expand...

Yes, you are quite correct. But one should note that your statement is contingent upon the aircraft being in normal, straight and level flight. And in all fairness, that is usually how the plane is flown.

However, if the plane is one of the other states of flight, then the plane can stall with the stick in the neutral position. In spins, for example, both wings are stalled, but one wing is stalled more thoroughly than the other, and in this case, keeping the stick in the neutral position will not break the stall and keeping the stick fully aft, will make the spin go from bad to worse.

Therefore, I think it wise to tell people that airplane can be stalled in any stick position.

As for your question about Angle of Attack and stick position goes, I think that Wolfgang L. said it best in Stick and Rudder, and if may paraphrase:

the Elevators are used to help set the Angle of Attack, but they do not always define the Angle of Attack. And while that may seem to be a bit obtruse, it is accurate when you think about it.

Supposing, that a plane is in normal straight and level flight, and the elevators are adjusted to a ten degree climb, then the Angle of Attack is ten degrees. And a bit more than ten degrees if one takes into account the Angle of Incidence.

But then suppose that the plane is straight and level flight with the stick in the nuetral position, however the power reduced so much that it results in a descening condition, then the Angle of Attack is already a positive value. Therefore, pulling the Elevators to the same ten degrees up will provide an Angle of Attack that is greater than ten degrees (and even more if the Angle of Incidence is accounted for).

I hope this helps!

Since this is Phase I testing, have you verified that you are getting proper elevator deflection limits? Could be as simple as that!

PCHunt said:

Stick position is directly related to angle of attack. (I'm sure someone will correct me if I'm wrong. Any test pilots out there.........?)

Click to expand...

I'm not a test pilot, but this is not true and is a dangerous assertion! For instance, in a true spin with the wing stalled you can hold the stick in neutral position or push forward and still be stalled!

In an approach to landing stall you could easily have the stick neutral or near neutral but exceed the stall angle of attack.

I realize you said straight and level flight but I do not think it is good to get people thinking that stick angle will tell them what the AOA is. Sometimes it is and sometimes it isn't. They need to know it is the angle of relative wind to the mean chord line of the airfoil.

Let me try again......

Bubblehead said:

....... In an approach to landing stall you could easily have the stick neutral or near neutral but exceed the stall angle of attack.....

Click to expand...

I do not believe your statement to be correct. I urge you to go fly and try it out. Do a very gradual 1 G straight and level stall, and note the stick position. Then do an accelerated stall, at say 110 kts. You will have to pull harder, but again note the stick position, in my experience it is the same. Then try an approach to landing stall, and again the stick position will be the same. Again, I have demonstrated this to numerous others during BFR's, and during upset training.

At a given CG, a wing stalls at the same critical angle of attack, no matter the attitude, no matter the amount of G, etc. The elevator position determines the angle of attack of the wing, barring out-of-control flight.

Once in a spin, you are no longer in normal flight, so my discussion doesn't apply, but many airplanes recover from spins by merely letting go of the controls, or placing them neutral.

BTW, flaps will change the stick position needed, so don't compare a clean stall with a full-flaps stall.

Again, go flying and try it, you might be surprised!

Spins in a 6 model

PCHunt said:

Once in a spin, you are no longer in normal flight, so my discussion doesn't apply, but many airplanes recover from spins by merely letting go of the controls, or placing them neutral.

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This is not true with the RV6 models. As Van himself points out, The turn revolution speed is quite an attention getter. The 6 series also needs positive Anti-spin reaction to stop the revolutions, even at incipient spins after 1 first turn, the spin will continue a 3/4 turn when centered elevator and opposite rudder are applied. 6 models are nothing like the mild spin characteristics of a Citabria or 150 Aerobat. It is interesting to note that my experience with 113BM (RV6A with RV8 rudder) is the revolution speed is even more of an attention getter that the 156PK (classic rudder). This is probably due to more rudder authority in the 8 rudder-(I would love to spin the 7 or 8 model some day and experience the difference).

But to get back to the original post, the climb pitch attitude of a full departure stall in a Vans model is just ridiculous. Specifically with a CS prop. A somewhat heavy right foot for a centered ball is needed in this procedure. I used gradual increasing low power settings to gain experience with departure stalls in phase one testing of 156PK. Even at just 15 inches of MP power (185HP) the approach to stall pitch angle is quite interesting. So when I say low power settings, I mean below 12 inches to start this procedure.

## Rant on ## I also can not stress enough, the importance of aerobatic/unusual attitude training for these Vans models. Even if you are not interested in aerobatics, the experience gained puts a pilot in a much more state of readiness and familiarization if an unusual situation should arise. ## Rant off ##

AZtailwind said:

But to get back to the original post, the climb pitch attitude of a full departure stall in a Vans model is just ridiculous.

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I will add that the climb pitch attitude for a max performance takeoff is also ridiculous.

After I installed the LRI indicator and started experimenting with max performance takeoffs using the AOA indicator, I quickly found that the RV-6 (O-320, fixed pitch prop, 1010 lbs empty) climbing at the bottom of the green arc on the LRI is pitched up at such an angle that a power loss below pattern altitude would most likely end very, very badly. In my case, flying solo at ~1000' density altitude, this was about 65 kts. I consider 90 kts (or well into the green LRI arc) a much better choice even though visibility over the nose is still very restricted.

The performance envelope of these planes is larger than prudence would dictate in many instances.

I don't do power on stalls

I gave them up years ago because the conditions that cause them are so unrealistic that I think it is impossible to have one on accident.

I didn't invent this thought. An instructor giving me a checkout in an M20R said we wouldn't bother doing power on stalls for this reason. The logic was compelling.

When I did the phase 1 testing on my new prop I did the required Vy & Vx tests. I tested down to 60 kts which is still 10-15 kts above power-on stall. The deck angle was extreme and it took a huge amount of right rudder. I couldn't see past the instrument panel.

I found that very uncomfortable and find it inconceivable that it could happen on accident.

That said, under low power conditions such as departing a high altitude airport I think it is possible, especially if you're getting anxious about clearing an obstacle. I don't think this applies too much to RVs because they have such good takeoff performance.

IMO, if you're going to do them, it is much more realistic to use a partial power setting to simulate a condition where one has any possibility of occurring on accident.

For what it's worth

Many, many moons ago I was going through the flight instructor program at Western Skyways in Troutdale. It came time for the spin training portion of the program so the instructor took us out to the practice area. He set the C150 up in cruise configuration, took his feet off the rudder pedals, and then started rolling the trim steadily back. The nose came up and up, and finally reached a point where the aircraft popped over into the nicest spin you've ever seen. No shudder or bucking and snorting to to let you know you were about to stall. It just went over slick as could be. So maybe in RVs the deck angle is so steep power on that you can't miss it, but what about being distracted by a traffic call where you are looking to the side or behind the airplane while climbing out? Personally, I'm going to want to know if the RV9 (still building) is going to let me know before it decides to stall power on. Just my 2 cents.