Another crash :(

[Jim Logajan]

Wow. Did not think my post could possibly provoke such a response.

Sorry. The reason I responded at all was your claim, like many others have, that loss of power on climb will cause a stall. This is a myth. The only way to bust a myth is to make people actually try it.

I only know that pilots surprised by an engine failure, for whatever reason and with whatever manipulation of controls, can and do see a rapid degradation in airspeed unless an aggressive "push" is involved. If that "push" is more like a massive decrease in back pressure, so be it - pitch has to be aggressively decreased no matter how you say it. Trim state comes into play as well.

Actually the cause of such stalls is the instinct to pull back on the elevator when the nose starts to drop.

I'm not alone. "A big push" is mentioned in this video:

Shucks no - you are not alone at all - you and many others have already made the claim. Note that the fellow who made that video had to resort to displaying a simulated airspeed indicator rather than a real one. We'll have decent flying weather here later in the week - I'll try to make the video that shows what really happens since no one else seems inclined to even dare try it, nevermind make a video recording.

Not interested in bets or getting into a back-and-forth to prove who's right. My visualization and explanation of what to do if the engine fails after takeoff has held me and my students in good stead for many years. If you prefer a different way to express it, that's fine as well.

Actual engine out demonstrations seem to be done only at cruise speeds in level flight (and sometimes descent), and then only to train for a requirement in the PTS. In such a scenario students are taught to slow the airplane - which involves a PULL since best glide speed is less than cruise. You (and others) are telling them to do the exact opposite if it happens in a climb, but how often do instructors physically demonstrate what happens on engine power loss during climb with, and without, touching elevator control? Looks to me like near zero.

As to the bet and "who is right": All I want to do is stop a myth that points people in the wrong direction as to solutions. I don't know how else to do that. What would you do if somebody posted "If you lose engine power in cruise flight, your airplane will stall unless you PUSH forward on the yoke."? And then you saw a whole bunch of alleged pilots and instructors post agreement?

 

[Jim Logajan]

I'm not sure I understand your bet. In the Cub, I climb out at about 60 with full power. I fly base and final at about 60 at idle. It seems like you're saying no trim adjustment should be needed. But that's not accurate. Eight or nine turns of trim are needed between takeoff and final. Langewiesche asserts that in an ideal airplane, the same stick position will give the same speed regardless of power setting. But the same trim doesn't give the same stick position regardless of power.

Not sure I understand (never flown a Cub.) Are you saying the trim setting for 60 on climb is different from the trim setting for 60 on final? Is it a J3 or Super Cub? That is, are flaps being used on final but not on climb?

 

[Dana]

Sorry. The reason I responded at all was your claim, like many others have, that loss of power on climb will cause a stall. This is a myth.

You can't make a blanket statement like that; all aircraft are different. For many conventional airplanes, yes. But fly a homebuilt with a high thrust line like a Kolb (or even a certificated aircraft like a Lake amphibian) and you better push forward right now if the engine quits, or even if you reduce the throttle. Very light or high drag aircraft (ultralights or near ultralights, and many biplanes) will slow down below stall speed before the aircraft's stability brings the nose down, and high thrustline aircraft need significant trim adjustments with power changes.

Other reasons to get the nose down fast are to maintain speed for maneuvering and/or flaring if at very low altitude, and to see better over the nose.

 

[yetti]

Sorry. The reason I responded at all was your claim, like many others have, that loss of power on climb will cause a stall. This is a myth. The only way to bust a myth is to make people actually try it.

What is your data set of planes flown that you think won't stall on loss of power?

The problem with stall training is that it teaches the wrong verbal reinforcement and muscle memory. When you hear the stall horn for real you want to pull back and put it further in a real stall like your instructor taught you....
Push is what you want to do when you hear the stall warning.

 

[gismo]

I disagree. "Feeling lighter in your seat" doesn't mean squat. Wing "loading" doesn't mean squat. Hell you could be accellerating fast to the ground (which is what makes you feel lighter) and be nowhere near recovering from the stall. The only thing that matters is DECREASING ANGLE OF ATTACK. And the only way you're going to get that is to move the controls forward. Framkly, I'd go to the stops. Yes, too many (including Colgan pilots) it is counter intuitive to PUSH when you're heading to the ground, but this is EXACTLY what you need to do and if you are close to the ground you better do it quickly and get recovered if you have a prayer of pulling out afterwards.

We may have to agree to disagree. To reduce the AoA you must "unload" (i.e. reduce the amount of lift). That could be accomplished by dumping weight but changing the pitch attitude is more practical. And airplane's don't accelerate fast to the ground in a stall, If you can manage to keep the wings level your average speed towards the ground will be fairly constant,

 

[iflyvfr]

Sorry, I did not see that LoganJan had responded to my controversial post. But I'm not afraid to take a bet and give it a try, not at all. When I get the opportunity, I will most certainly take your bet for the good of the order and my own edification.

However, it is my opinion that if I can avoid stupid pilot "watch this" tricks, the next mostly likely thing to kill me is an engine failure on takeoff. I've read enough NTSB reports to know that many times otherwise excellent pilots are killed because their recovery from a system failure didn't hold up. So yeah, I'm in the avoid a stall at low altitude camp and if "PUSH" is what gets me there, well I'm ok with that. Altitude & airspeed is life and my goal is to try to reduce/eliminate that "oh Sh~t" pause when seconds may be critical.

For years I told my wife, if the engine ever quits, the only thing I want you to say while I'm working the problem is "don't stall, don't stall". I've stalled my airplane (recently) and I've spun it a few times too. But I'm convinced a lot of pilots meet their demise as a result of a low altitude stall/spin and when the fan quits, it seems to me a push is a far better option than a pull.

 

[Lindberg]

Not sure I understand (never flown a Cub.) Are you saying the trim setting for 60 on climb is different from the trim setting for 60 on final?

Yes, very different.

Is it a J3 or Super Cub? That is, are flaps being used on final but not on climb?

J3, no flaps.

 

[denverpilot]

I think Jim's assertion is correct for a lot of airplanes that most recreational pilots fly.

The problem with it is a couple of things:

- People don't trim away forces well during takeoff. The "takeoff" trim setting is relatively neutral and requires a steady pull.

- Some large percentage of people freeze when presented with something bad. e.g. An engine failure at low altitude in a takeoff.

Yes, if they relax and RELEASE the yoke or stick, the airplane will probably have the nose fall down naturally and it'll maintain some sort of reasonable airspeed and AoA.

Problem is, besides freezing, the next instinct to overcome is the fear of all that dirt suddenly showing up rapidly at the bottom of the windshield and coming up a significant way up it. There's trap number two... and the pilot wants to pull to stop that.

So we've got two real human behaviors to teach pilots to avoid on departure if the engine quits. Both are "pulling".

I bet if you could ask a pilot who had to counteract this, we hit the next problem. A perception problem. They're going to tell you they "had to push" to maintain airspeed and lower AoA. Whether they actually pushed or not, they stopped pulling and their brain may very likely remember it as a push.

So... until they've got the experience, and getting low level engine power loss experience is not all that easy to get, and simulations don't truly cover it -- that adrenaline dump is going to be big, number four item working against you -- if instructors are saying PUSH, I can see why.

It has much more to do with human dynamics than it does aerodynamics. A poorly trimmed airplane with a pilot who just had a massive jolt of adrenaline, who's already pulling, and wants to pull some more as the sight picture changes, isn't going to have a lot of brain bandwidth left to remember much. If all they remember is PUSH for airspeed, they can accomplish that. They're probably just RELEASING back pressure completely or even pushing a little and then realizing that was "too much" and then correcting it.

And that PUSH? It's not going to be too much if they're 1000 AGL and need a tight turn, RIGHT NOW to turn to the runway environment, since it's going to bleed off energy significantly... a push past Vy descent speed won't seem like enough of a push once the turn of at least 45 degrees of bank starts.

So, Jim's "right" but I don't see anything "wrong" with teaching humans who are obviously wired to PULL to PUSH instead, if it'll keep them well above stall speed where they can regain their rational thoughts and land "straight" ahead or make a pre-practiced turn maneuver if they have the altitude to do it. They're going to THINK they PUSHED anyway.

 

[FastEddieB]

denverpilot's last post just about perfectly summarizes a post I was mentally composing since last night.

I have to be honest - I think he put it better than I might have.

So, in short, "Ditto"!

And a great post.

 

[Hank S]

Yes, very different. J3, no flaps.

Put it down to aircraft differences. I trim for hands off climb, and for hands off descent in the pattern. Often when I land, the trim position is very near the Takeoff position.

But climb is clean, landing has some (variable as needed) amount of flaps, starting before I begin descending from TPA. Eliminate the flaps and the trim position will be very different . . .

Accelerated stalls, as on departure, require LOTS of push, even when not done at full throttle. When the engine conks out at cruise, there is an immediate and significant pitch down.

Don't recall doing a departure-style engine out, but I would also expect a pitch down would follow, assuming trim is used for the climb. Don't have a camera to mount in my plane, or I'd go for $50.

 

[Lindberg]

Put it down to aircraft differences. I trim for hands off climb, and for hands off descent in the pattern. Often when I land, the trim position is very near the Takeoff position.

But climb is clean, landing has some (variable as needed) amount of flaps, starting before I begin descending from TPA. Eliminate the flaps and the trim position will be very different . . .

Accelerated stalls, as on departure, require LOTS of push, even when not done at full throttle. When the engine conks out at cruise, there is an immediate and significant pitch down.

Don't recall doing a departure-style engine out, but I would also expect a pitch down would follow, assuming trim is used for the climb. Don't have a camera to mount in my plane, or I'd go for $50.

The claim was as to all planes.

I bet you $50 that if you take an airplane up to the altitude where you practice stalls and put it into a Vx or a Vy climb and the airplane's balance is within its Cg limits and you cut the engine and keep your hands off the elevator control and you video the airspeed indicator, it will barely budge (a few knots at most) from the trimmed climb speed

And it sounds like your plane is the same. To maintain the same speed engine out, without changing trim, it sounds like you have to change the configuration.

Leave the stick alone, and the plane will eventually stabilize at a slower airspeed all by itself. If you do that shortly after takeoff, you might be dead before it happens. The point of the push is to get your airspeed back now.

 

[BigBadLou]

I'm not alone. "A big push" is mentioned in this video:

Be careful, do not put your life in the hands of random people on the Ynterwebs.
As a smart pilot, you should be able to collect information, analyze it and learn from it. Memorizing BS from the Ynterwebs and treating is as gospel could get someone easily killed.
If you watch this video carefully, it turns out to be a lie. At 0:30, as the pilot transitions from a powered climb to a power-off descent, his backpressure on the yoke does not change so he is not pushing. So the author of the video nicely contradicts himself.
Again, analyze and create your own educated conclusions. Don't believe just any BS posted on them Ynterwebs.

As pilots, we were taught to continually monitor, analyze and evaluate best course of action.
Be smart and be safe!

 

[jsstevens]

Be careful, do not put your life in the hands of random people on the Ynterwebs.
As a smart pilot, you should be able to collect information, analyze it and learn from it. Memorizing BS from the Ynterwebs and treating is as gospel could get someone easily killed.
If you watch this video carefully, it turns out to be a lie. At 0:30, as the pilot transitions from a powered climb to a power-off descent, his backpressure on the yoke does not change so he is not pushing. So the author of the video nicely contradicts himself.
Again, analyze and create your own educated conclusions. Don't believe just any BS posted on them Ynterwebs.

As pilots, we were taught to continually monitor, analyze and evaluate best course of action.
Be smart and be safe!

Better yet, try it in the plane you fly!

The late chief instructor for the club I used to belong to took me out for two trips (different times) where we hung around the pattern and he pulled the throttle on me at various places to see where and how I could get the plane back (or choose where to put it). I was surprised that it wasn't a push (C-172C). But I wasn't frozen by surprise of course. Other than if the flaps change, trimmed for air speed in the C-172 is trimmed for airspeed. And I could turn much faster than I would have thought. I am forever grateful for the experience and I have a great deal more confidence in handling such emergencies. And I'm going to try it again in the Piper Archer (At altitude) because I'm sure its different than the 172s.

But go to a safe altitude, and try it instead of arguing about it here. It's well worth practicing and you will learn something even it's only that you were right in the first place.

John

 

[Jim Logajan]

You can't make a blanket statement like that; all aircraft are different. For many conventional airplanes, yes. But fly a homebuilt with a high thrust line like a Kolb (or even a certificated aircraft like a Lake amphibian) and you better push forward right now if the engine quits, or even if you reduce the throttle. Very light or high drag aircraft (ultralights or near ultralights, and many biplanes) will slow down below stall speed before the aircraft's stability brings the nose down, and high thrustline aircraft need significant trim adjustments with power changes.

Other reasons to get the nose down fast are to maintain speed for maneuvering and/or flaring if at very low altitude, and to see better over the nose.

I don't dispute anything you wrote - you are correct. Also, I did not intend to make a blanket statement applicable to all airplanes. Earlier in the thread I wrote the following with the intent to narrow my assertion:

In fact, no airplane designed to Part 23 standards for trim and longitudinal stability will exhibit the behavior that you claim.

 

[Jim Logajan]

What is your data set of planes flown that you think won't stall on loss of power?

I've only experimented with a C-152 and C-172. That's all that is available for rent at my FBO.

 

[Jim Logajan]

Sorry, I did not see that LoganJan had responded to my controversial post. But I'm not afraid to take a bet and give it a try, not at all. When I get the opportunity, I will most certainly take your bet for the good of the order and my own edification.

Great! If it doesn't slow to a stall, make a $50 donation to Angel Flight West. If it does, let me know where I should send my $50. I've reserved some time for Friday afternoon in the local C-152 to see if I can get some videos of the attitude indicator, airspeed, and throttle. (Last time I did the experiment I found that the engine did not like throttle being cut fast.)

 

[Jim Logajan]

Yes, very different. J3, no flaps.

I had time to ponder your experience during work today - all I can think that is different between climb and landing is that the engine is at full throttle on climb and much reduced throttle on landing, so the different trim settings might be due to different amounts of propwash over the tail in each scenario. The J3 Cub was designed quite a while back, so the longitudinal requirements back then (to the extent they existed at all) differed from current Part 23 standards.

 

[Kevin16587]

I live in Lexington, KY for several years so fly into Rough River, and even Hopkinsville on occasion. Had my maintenance done at KOWB also. That is sad. For some reasons, these hit closer to home when they happen in areas we know, or have lived.

Agreed. I'm originally from Hopkinsville.


Sent from my iPhone using Tapatalk

 

[James331]

Uhh, maybe just do whatever you have to do to get best glide.

Maybe that means pitch up, maybe stay level for a second or two, maybe push the nose down, whatever. Just do whatever you need to get best glide.

As for trim, F' that, that's the last thing on my mind, I'll get best glide, head towards my landing, and if I have time trim the force off. All this nonsense about do this and that and the plane will automatically go to best glide, yeah trust that and play that game when chit gets real, good luck.

Just get best glide, point and fly to where you're landing, and don't stop flying till the ride comes to a complete stop.

 

[BigBadLou]

Also, for FWIW, piston engines usually die gradually instead of abruptly, making this silly push initiative moot since the airplane nose will follow the slow power reduction (to 0) with a downward trend.

 

[yetti]

I've only experimented with a C-152 and C-172. That's all that is available for rent at my FBO.

Yes those planes will just mush their way down. Other planes like a mooney would flip you over in a spin to the ground. You might want to expand your data set of planes before you make sweeping generalizations.