Stalls and slow flight poll/discussion.

[cnoe]

I'm following up on 201ers recent posts that provoked some mildly provocative discussions.

Much was said about the stalling characteristics of the M20 which made me realize it had been 6 months or so since I'd practiced a slow-flight/stall regimen. In fact some of the talk focused on how abrupt and dangerous M20 stalls can be. I got to thinking so I went out yesterday and completed some stalls and slow flight in various configurations. Here are a few random thoughts on the subject. Comments and others' experiences are welcomed.

First of all I was light at around 2,250# (2,740# gross). About 70# of my load was in the baggage compartment but the 3 seats were empty. The IAS at which I stalled was pretty much spot-on based on my weight and configuration so I feel good about the ASI calibration. It amazes me that I can fly at 50 kts in landing configuration as the plane gently settles (though it's right on the brink of a more abrupt stall). With the gear down and both full flaps/half flaps my J wanted to consistently drop the left wing when at a low power setting (as if landing). If recovery is initiated quickly (ailerons level, yoke briskly forward, opposite rudder) it would straighten up quickly with little altitude loss. But as I explored the recovery characteristics I can attest that a secondary stall can occur if the yoke is pulled back too soon (even when airspeed appears to be sufficient). I did not allow the secondary stall to develop as I understand these can be quite violent.

When re-creating a full-power (departure) stall the break seems to occur a bit more quickly but was still quite manageable. With 15 degrees of flaps deployed it still wanted to break left upon stalling on the two occasions I practiced that configuration. But...

On another full-power stall with NO flaps it surprised me and actually broke "right"! Though I was doing a fair job of keeping the ball centered it dropped the right wing in two consecutive instances while in this configuration. This leads me to believe that one shouldn't necessarily count on a particular direction of stall break (this is even more true when the stall is unintentional and you may not be watching the ball).

Lastly, I'd like to add that it also amazes me what an incredibly acute climb angle is needed to stall in the clean/power-on configuration. I failed to note the number of degrees nose-up on my attitude indicator but I can tell you it felt/looked like I was going straight up. It was literally hanging on the prop, and still flying. I can hardly imagine putting my plane in this attitude unintentionally outside of IMC conditions. Still I'll remain vigilant.

YMMV

I'm attaching a screenshot from my CloudAhoy app showing just one moment in time during all this. It's pretty accurate and a great tool for analyzing this stuff.

 

[MB65E]

I did a series like that about 8 mo ago. I played with decent rates. Power off 360s with aggressive bank angles. With the prop back I was shocked I could do a 360° turn at 85kts in about 400 feet. Very good idea to practice. However, if your not comfortable, find some one who is. It will be worth your time. 

Flysafe,

-Matt

[AndyFromCB]

Never. What's the point? It was a traveling machine, not a trainer. 

[Ron McBride]

I have always shied away from stalling my Mooney.  To many horror stories.  I would always do approach to stalls, let it shake and them push the nose down and recover, never fully stalled.  Last bi-annual, my instructor had me do many stalls.  Do them coordinated and no problem.  I will be doing some more soon.

Ron 

[gsengle]

You need to train in the airplane you fly whether it is a traveling machine or not. That is if you want to be safe.

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[Danb]

In an attempt to not change the topic, the cloud ahoy app looks very useful, how hard is it to use i.e.. download etc to acquire the info as depicted in CNOE's post?

Any info would be useful

 

danb

[carusoam]

Did some slow flight, maintaining altitude, stall horn on, everything behaving normally.

Got a predictably really nice landing following that exercise...

Power-on stalls come with pretty noticeable nose high attitudes.  The brain must be very loaded up to not notice, or find acceptable..?

Thanks for sharing the CloudAhoy data.

Best regards,

-a-

 

[carusoam]

Dan,

As part of my relearning, I used the CloudAhoy app.  It is incredibly easy to use, runs in the background on the iPad, and gives a tremendous amount of info when connected to the Internet later.

for typical PP maneuvers it identifies, measures and helps you grade your skills... One of the first maneuvers I captured was a 360° turn, sans AP...  

for best results for T/O and landing distances, combine with a WAAS receiver, like sky radar...

Best regards,

-a-

[DXB]

Cautious, coordinated slow flight at 80 mph in landing config for practice - yes - I actually think the feel improves my landings.  Full stalls - never ever on my own. Only with a very experienced and trusted Mooney instructor on board - so almost never basically.  I will do some in December to complete the wings credits for my flight review.  Even then, not too excited about doing power on stalls.  

[cnoe]

In an attempt to not change the topic, the cloud ahoy app looks very useful, how hard is it to use i.e.. download etc to acquire the info as depicted in CNOE's post?

Any info would be useful

 

danb

CloudAhoy has added much functionality over the past couple of years and can provide lots of data and great feedback if you subscribe to the paid version. And the free version is still good for tracking flights.

As an added benefit just last week I utilized it to get myself out of the doghouse following a period of spending excessive time at the airport/flying. It's all about flight planning you know!

Sent from my iPad using Tapatalk

[bradp]

I typically do slow flight with approach to stall / stall indication instead of getting into a fully developed stall in the Mooney.   

 There is valuable information here regarding which wing drops first and avoidance of secondary stalls, but what I really like to focus on is the characteristics of the airframe (besides the horn) that tell you you are about to stall.  Recognition.  I don't really need to drop a wing to help me learn pattern altitude survival skills.  

Thats just my take, however.

Give me a Hershey bar wing and I'll happily mush it into a falling leaf.  Not so much with the laminar wing.  

 

@DXB interesting I just did my wings and the curriculum that it suggested for me had no slow flight/ stalls / air work to be done but did have me complete an IPC. It also included power of 180s from the commercial PTS.  It was fun but I was surprised that I got my flight review substitute without a slow flight or stall demonstration.  

Most interesting prior flight review I had was conducted at night.   That was good learning.  

Best part about this most recent one was that @GeorgePerry signed my online certificate. 

[201er]

1) I see no value in practicing stalls. Instructors and examiners are so hung up on making you stall completely and seeing the break. Beyond some initial training so you know what it is like, there is no benefit to stalling that far. Being able to recover early is better and it is shameful that instructors are more hung up on teaching you how to stall rather than how not to.

2) There is value in practicing stall recovery. As the stall begins, recover.

3) Better yet learn how to fly so you would never stall unintentionally. Be aware of angle of attack in all phases of slow flight. No, dentist, that does not mean the only way is to buy some stupid gadget. Even without an angle of attack indicator, it is possible to be more aware and think in terms of angle of attack rather than airspeed.

4) That brings me to point #4, forget about airspeed. Airspeed is not a direct measurement of angle of attack. Given many variables, that value needs to be adjusted. Even if you always fly the same way (2 guys, fuel at tabs), don't get too attached to a single airspeed number. Realize that this number is free to change on a case by case basis.

5) Don't spin a mooney!

6) Be really high when you do intentional practice stalls.

7) The kinds of stalls most instructors will have you practice are not the kinds of stalls you'd inadvertently get yourself into. Straight ahead, at light weight, etc you'd have a hard time stalling the airplane. In a power on stall, you'll be laying on your back having a hard time getting it to stall and the instructor will be yelling at you that you're not trying hard enough. This is retarded. There is absolutely no value in this. More likely, the real inadvertent stall, will be at a much lower pitch attitude (but still as high of an angle of attack). Why? Because there will be more weight, more bank, and more load factor. As you add those in, the pitch angle for achieving such a high angle of attack isn't all that high at all! This is why learning to fly by angle of attack is so much more useful than learning how to stall an airplane straight ahead.

8) If you can fly slow, control your angle of attack, stay coordinated, and fly at high angle of attack continuously without stalling, why practice stalls?

9) Fly the right angle of attack with some margin in all phases of slow flight and stalls should be irrelevant. Just don't let them happen. Fly safe.

[cnoe]

43 minutes ago, carusoam said:

Got a predictably really nice landing following that exercise...

Best regards,

-a-

 

You sure got that right!

Strangely enough the landing was one of my best ever; so much so that I went home and bragged to my wife about it.

She wasn't impressed.

[bradp]

At least they were practicing stalls over a lake.  Skip ahead to 2:56.  It looks like he may have stalled it, lowered the angle of attack and then increased it again.   The wing drop looks like it turned into a half turn of a spin (I couldn't tell if it was fully developed).   This is why I don't practice fully developed stalls in the Mooney  

 

[201er]

50 minutes ago, carusoam said:

Power-on stalls come with pretty noticeable nose high attitudes.  The brain must be very loaded up to not notice, or find acceptable..?

Nope. This is because real power-on stalls don't happen that way. I've had some close calls to power on stalls on departure when heavy at high DA. There are a couple of things working against you and the pitch attitude never looks like that crazy laying on your back with your instructor power on stall. Firstly, when you go practice stalls, you are usually pretty light (you + instructor or just solo). The plane has way more power available so the vertical component of thrust is significant. Maybe try it at reduced throttle. Next, on that day that you get yourself in a bind with a power on stall, you probably have all of your fat friends and luggage on board. CG will be further Aft! Most likely this won't be in winter either. Hot Day, higher DA, or actually the one time you go to a higher elevation field. Next, a little bit of uncoordinated flight (perhaps not enough or too much right rudder in the climb). Perhaps a bit of a turn?

The biggest issue is going to be the speed lag on takeoff and breaking ground effect. The angle of attack ends up higher than you expect at a lower pitch attitude. You'd be way behind the power curve and barely or not climbing at all. It will look like a pretty much normal pitch attitude. Definitely not the laying on your back pointless power on stall the instructor made you do.

The solution? Fly by angle of attack and not by airspeed. Preferably an AOA indicator, but even just forgetting about airspeed values and thinking about the angle of attack of the airplane in each configuration. If you reference Vx and Vy as angles of attack and not as airspeeds, you are more likely to get better performance (which makes you less likely to inadvertently pull back) while also having greater stall margin.

Vx/Vy are typically referenced in the POH for gross weight at sea level at standard temp. Guess what? Accidents tend not to happen under ideal conditions. I'd bet you many of them are at higher than standard temp/altitude (if not over gross). So the POH published numbers will be least helpful when you need them most! Fly by AOA. That's the only thing that actually affects the wing.

[PTK]

1 hour ago, 201er said:

I see no value in practicing stalls...

...forget about airspeed.

I strongly disagree on both.

The reason we teach stalls is not to fully stall the airplane and spin it. We teach stalls to help the student develop a feel and recognition for the airplane's slow flight and stall charactetistics. These are skills necessary to properly slow down and land the airplane. 

A stall can happen at any airpeed and from any attitude and it is a function of angle of attack. There are way too many stall/spin accidents in the traffic pattern every year. Most are a result of pilot's failure to maintain airspeed. I don't know of any airplanes that stalled and spun when sitting still on the ramp. No matter the slope of the ramp. Similarly not too many stall and spin in cruise. The overwhelming majority of these fatalities happen while maneuvering in slow flight in the pattern. 

[Andy95W]

Here we go again.

*this image shamelessly stolen from Peter (PTK)

[Danb]

1 hour ago, 201er said:

 

8) If you can fly slow, control your angle of attack, stay coordinated, and fly at high angle of attack continuously without stalling, why practice stalls?Fly safe.

Arguably the most valuable flight practice excercise known.

[peevee]

yikes, spun it and then tried another stall.

[cnoe]

34 minutes ago, 201er said:

Nope. This is because real power-on stalls don't happen that way. I've had some close calls to power on stalls on departure when heavy at high DA. There are a couple of things working against you and the pitch attitude never looks like that crazy laying on your back with your instructor power on stall. Firstly, when you go practice stalls, you are usually pretty light (you + instructor or just solo). The plane has way more power available so the vertical component of thrust is significant. Maybe try it at reduced throttle. Next, on that day that you get yourself in a bind with a power on stall, you probably have all of your fat friends and luggage on board. CG will be further Aft! Most likely this won't be in winter either. Hot Day, higher DA, or actually the one time you go to a higher elevation field. Next, a little bit of uncoordinated flight (perhaps not enough or too much right rudder in the climb). Perhaps a bit of a turn?

The biggest issue is going to be the speed lag on takeoff and breaking ground effect. The angle of attack ends up higher than you expect at a lower pitch attitude. You'd be way behind the power curve and barely or not climbing at all. It will look like a pretty much normal pitch attitude. Definitely not the laying on your back pointless power on stall the instructor made you do.

The solution? Fly by angle of attack and not by airspeed. Preferably an AOA indicator, but even just forgetting about airspeed values and thinking about the angle of attack of the airplane in each configuration. If you reference Vx and Vy as angles of attack and not as airspeeds, you are more likely to get better performance (which makes you less likely to inadvertently pull back) while also having greater stall margin.

Vx/Vy are typically referenced in the POH for gross weight at sea level at standard temp. Guess what? Accidents tend not to happen under ideal conditions. I'd bet you many of them are at higher than standard temp/altitude (if not over gross). So the POH published numbers will be least helpful when you need them most! Fly by AOA. That's the only thing that actually affects the wing.

I appreciate your input and believe that you have some valid points, but I also believe your thinking may be a bit dogmatic.

Departure and approach stalls do happen, flying straight ahead. But I'll acknowledge that the base-to-final turn is likely a more common scenario.

The primary reason I practice stalls is to improve my instinctual reaction to the break. Slow flight can be valuable in teaching one how the plane handles approaching a stall as well but for me the big benefit is (automatically):

1) keeping ailerons NEUTRAL rather than trying to roll out of a stall

2) applying the CORRECT (brisk) rudder input rather than spending time deciding how to react

3) and of course pushing the yoke forward briskly

When the stall is immediately recognized and the appropriate control inputs utilized your descent can easily be arrested in less than 200 feet if you are anticipating the stall. If you are SURPRISED by it then the recovery will be obviously extended, but by practicing these things it is my opinion that your chance of survival is greatly enhanced.

I should probably practice high AOA "turns" (at a healthy altitude) as well, but this seems more risky to me as the resulting stalls might be more aggressive. I'll have to work up to those (possibly with somebody like Jetdriven riding shotgun). I have no interest in doing cross-controlled stalls in my Mooney.

By practicing straight stalls at least I'm more prepared for the scenario I'm most likely to encounter (a distraction such as the dog barfing on my head during approach or departure).

I get the whole AOA indicator thing; I flew with one for 2 years in another plane but I don't miss it terribly in my J. I'll likely add one to it sometime in the future but the AOA indicator in my head and butt serves me pretty well already. Airspeed isn't "useless" if well understood, and I believe most people here do understand its limitations.

Lastly, I have no objection to using whatever tools you have at hand in flying be it speed-brakes, forward-slip, or a 45-degree banked turn as long as they're used appropriately. I'd suggest that a stabilized approach is best for most situations but some situations require other tools. Not everybody agrees but that doesn't mean they're not safe pilots.

[PTK]

2 hours ago, 201er said:

...Vx/Vy are typically referenced in the POH for gross weight at sea level at standard temp. Guess what? Accidents tend not to happen under ideal conditions. I'd bet you many of them are at higher than standard temp/altitude (if not over gross). So the POH published numbers will be least helpful when you need them most! Fly by AOA. That's the only thing that actually affects the wing.

Come on man! Enough already! I have asked you before but you have no answer. I ask you again: How does your Vso compare to that in your POH? I routinely turn off the runway in ~1300 feet. How about you?

[cnoe]

Isn't Vso based simply on IAS? That shouldn't have anything to do with DA or OAT should it?

Even at 7,000' DA and 18 C. I still stall at the POH values.

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[FloridaMan]

I'm uncomfortable when it comes to doing stalls because of the stories I've heard about Mooneys and I haven't done them without someone more experienced with me. 

With that said, I've never had the Mooney do anything unexpected on a stall. I don't use the ball. I look outside and focus on something to keep the nose pointed towards. 

Watch videos of spins and stalls where wings drop. You'll notice that as the plane starts to stall, the pilot is unaware of the increase in yaw at the high angles of attack moments before the stall. 

[N201MKTurbo]

Two days after I bought my current Mooney I needed a BFR. We went out at night to do the BFR. (How many of you have done a BFR at night?) We did slow flight without incident, then I did a departure stall OMG the plane snap rolled almost inverted. I told my instructor we weren't doing any more stalls. He agreed. 

The plane was horribly out of rig. The yokes were at about a 20 deg angle while flying straight and level. After I fixed the rigging I went out and stalled it and it stalled very nicely and straight ahead.

The bottom line is if someone says their Mooney is scary when they stall, they are probably right. If someone says their Mooney stalls benignly they are right too. If your Mooney is scary when you stall it, it can be fixed. (and your plane will probably go faster)

[ArtVandelay]

How does Cloudahoy know your IAS?