This is why you dont turn back

[Guest extralite]

A stall with a boot full of rudder (incipient spin entry) so not surprised as to the outcome, I would imagine most low wing aircraft would be similar? Just went up and tried it in my RV7, about 30 degree angle of bank and skid ball half way to the outside. At the stall it did roll and pitch down fairly quickly, but height loss was 350 feet rather than the 800 mentioned in the video and no roll past 45 degrees, wings actually rolled to quite level. So i am guessing in the video there may have been a lot of rudder inbalance or held in the stall so maybe not that real life. As for turnbacks, taught them in the RAAF days so I am not suggesting trying them without lots of instructio, but there is no way the aircraft should be in a nose high turning attitude as per the video. First thing we did was bury the nose, it cuts down the radius of turn significantly because it becomes more of a roll, as well of course as avoiding a stall. In the RV at height just then was achieving a 180 degree turn from a nose high low airspeed (70 kt climb) entry in around 350 feet. Obviously wouldn't be doing a turnback at that height but good to be aware of.

 

 

[poteroo]

First thing we did was bury the nose, it cuts down the radius of turn significantly because it becomes more of a roll, as well of course as avoiding a stall. In the RV at height just then was achieving a 180 degree turn from a nose high low airspeed (70 kt climb) entry in around 350 feet. Obviously wouldn't be doing a turnback at that height but good to be aware of

A fixed pitch RV spoils a pilot outrageously. They are so clean, and decelerate so slowly that you have several options. With RV's I teach accelerating through 100 KIAS before beginning any climb. This doesn't take long and we are usually about 150-200 ft by then. From that position, you have choices. More - if you are 350 agl as in the vid. More again if you have reached 110 KIAS.

 

You can position yourself for an off airport landing if there are plenty of good options, OR, try to make a 180. I know, I know - this is a bad example for low experience pilots. Bear with me.

 

As a demonstration, I close my eyes, have student pull power to idle as we pass 100 KIAS - count for 3 seconds to simulate 'response' lag - open eyes - decide which way to turn - then roll into a 40-45 aob and hold the nose down to keep speed to no lower than 80-85 KIAS. This gets you around 180 deg very quickly, and it usually results in you being even a bit high to land down wind. Of course you are going to be turning close to obstacles, and terrain, and need to stay focussed. You'll have a lot of earth and but a little sky in the windscreen. Some low level experience helps.

 

Barry Schiff has written on this EFATO manoeuvre in his excellent books and article is US publications. And he's a reputable airman - something of a living legend in fact.

 

There was a vid posted on pprune a few years back showing someone doing this very thing at Caboolture in an RV if memory serves me.

 

happy days,

 

 

[facthunter]

Many things are possible if done exactly correctly. If someone demonstrates it can be done it's not automatic that others will also pull it off. If there's any doubt in flying make it no doubt and don't do it till you know you can, or cannot. This involves training of a specialised nature. Once you lose control of a plane, what happens is pretty much in the lap of the gods. (All very obvious). Nev

 

 

[Icarus]

Greetings.

 

Can some one confirm my theory of what is happening in the previously posted video please?

 

1. The aircraft is decelerated to approximately 25 kn above level stall speed . say 50kn level stall .

 

2. the 45 * turn brings the stall speed up by x 1.41 so approximately 70 knot stall in 45 * level turn.

 

3. the inside wing is now about 3kn above stall speed ,the outside wing about 7kn above stall speed.

 

4. The overuse of left rudder now causes yaw left, reducing left wing speed to below stall speed.

 

5. The right wing is still above stall speed and flying. over we go.

 

Thanks Brendan

 

 

[frank marriott]

2. the 45 * turn brings the stall speed up by x 1.41 so approximately 70 knot stall in 45 * level turn.

Being picky but from memory I think the wing loading of 2 is actually 60° .

 

 

[ron dunn]

If you want to appreciate what balanced flight is about, some glider training (thermalling) will give you a good insight.

 

To maintain a climb in a thermal, balanced flight is a must. Quite apart from the fact that you are usually flying near the stall in a thermal most of the time and departure into a spin is real and can happen quite quickly.

 

 

[Nightmare]

That is what my instructor/CFI taught me, it was called "wing drop training". It scared the you know what out of me, and I asked him, "Do I have to do this?" He said, "It's part of the curriculum" So I did about 3 or 4 of them. You need to know what to do if you get into that situation, so I disagree that it is dangerous or irresponsible, as it is part of the training. As I said, it is actually part of the flight training syllabus for the issue of RPC, so I would say that it is dangerous and irresponsible if an instructor doesn't teach his/her students this.

 

 

[facthunter]

To train that form of stall appreciation is fine and I've constantly advocated it. Using it as a flying technique to tighten the turn radius is deadly. Steep bank with unbalanced rudder will produce some startlingly fast results if a little back stick applied (normal reaction) at the same time.. Try some flick rolls in a suitable plane. Training I'm keen on. Unusual attitude recovery (as distinct from aerobatics) should be mandated for all U/L pilots but particularly for ALL instructors. Nev

 

 

[Nightmare]

Did you see him do the HASELL check before he did it? He stressed several times to never do a skidding turn or a maneuver that will cause this situation to occur, without altitude. They lost about 1000' each time they did it. From memory, I lost about the same each time. What was scary was seeing the speed rocket up near the Vne just before pulling out, that and being upside down when that wing drops. He taught me this on my very last lesson before I was issued with my certificate, so it was in a sense, advanced training, but I stress, part of the requirement to pass the certificate.

 

 

[facthunter]

A spiral dive will stress the airframe if an early recovery is not initiated effectively. Few RAAus planes are suitable for training in this . Spins, Stalling, Spirals are all associated and recognition of the situation you are in quickly, is essential. There is a minimum height for recovery from some of the situations you may get the aircraft into. It differs from one aircraft to another. Could be more than 1500 feet. depending on how far you let it go.Nev

 

 

[Guest extralite]

For Icarus..apologies if this is what you meant but the stall speed is a function of G (wing loading) rather than angle of bank. A balanced level turn at 45 degrees can give 2g, and so stall is speed is square root of 2 (1.41) the normal 1 g stall speed. Balanced level 60 degree turn will give 4 g and so 2 x 1g stall speed (square root of 4).

 

In the video it wasn't a balanced level turn, probably less than 2 g, so stall speed could have been anywhere but probably less than 1.4 Vs. The other thing apparent in this video is that after the stall, the down going wing has a higher angle of attack. Normally this is what keeps an aircraft stable, but after the stall it deepens the stall on the downgoing wing so further increasing the wing drop. Another reason to unload the g as soon as a wing drop is felt.

 

But unloading, rolling wing level and pulling to the horizon (incipient spin recovery) ensures a pretty quick recovery.

 

 

[BoxFat]

Every time I see a topic like this I think it gets mixed up between flying skills of instructors and teaching skills of instructors. In my experience there are skilled pilot instructors and skilled teachers and if you are really lucky as a student you get both together. As a a young student one is often a bit in awe of "God", even if they are not much older than yourself. If they are, all the authority figures one has had come into play and the dynamic that can arise is not very good for learning. Now that I am (considerably) older and more confident in life generally I can separate the "personality" from the lesson and it matters less who it is in the other seat. In fact, it's great fun working through it and pushing back a little from time to time and taking, with humility, control of my own learning.

 

Cheers,

 

BF

 

 

[BoxFat]

Oh - and next time I get into the RV-9A now available for hire (after thorough check out) at Albany aero club I will be asking my instructor to show me at least the beginning of this exercise. I know the theory but have never been great at sensing the out of balance condition through the seat. Probably not helped by flying my Foxbat as it is outrageously tolerant of cross controls and in fact it is a normal, fun and quite often necessary part of the repertoire.

 

My insurance is that I am pretty conditioned to getting the nose down to unload the wing if finding myself in any significant bank at low altitude.

 

 

[diesel]

Bank,balance speed.

 

This is a greatsubtleeo of why you don't try to turn back after engine failure

 

 

Thats nothi

 

 

[flying dog]

This is a great video of why you don't try to turn back after engine failure

 

 

 

rnot much good if not on book face.

[Icarus]

Bank Angle ...... Load Factor ..... Stall Speed

 

....30°.... ...... .. 1,15 G ..... 1,07

 

.....45° ............ 1,41 G ..... 1,19

 

.....60° ...... ... 2 G ...... 1,41

 

......75,5° ......... 4 G ...... 2

 

Thank s Frank and Extralight.

 

I was confusing load factor with stall speed. You can see how this might happen looking at the table I copied above.

 

So the stall speed in my example : 50 kn level stall speed . Stall speed at level turn 45* bank angle =50kn x 1.19 = 59.5kn

 

Thanks for the corrections

 

Brendan

 

 

[Nico13]

rnot much good if not on book face.

Search for Eddie Seve on Youtube or follow this link

 

 

 

[JerzyGeorge]

This is great lesson I have just been through real efato at 500 feet or less, made Mental commitment not to turn back, . Gentle coordinated turns only while selecting outlanding 30 deg. of the nose.

 

I had only a minute or less and instinct ( hammered into my brain by instructor long time ago) kicked in. Practice and refresher exercise at least once a month payed off on the day.

 

 

[facthunter]

That decision at that height is good and confining your areas to 30 degrees or so off runway heading and using the into wind direction of turn if possible, is pretty standard stuff, proven to be the best advice generally . YOU did the right thing.

 

No two situations are the same though . IF you have thought about where you will go prior to opening the taps. You are even better prepared. IF you have a very long runway you may want to lose height quickly and land on the remaining runway available. This may require taking full flap and diving the height of quickly, rather than gliding at best speed and a more positive flare. Regarding those stall speed variations with bank angle.... In a tight situation you are not going to be looking much at the airspeed, so practicing steep gliding turns gives you a knowledge of your planes nose down attitude needed and some awareness of the stick position, should be trained into you.. You don't want to bang into a large tree trunk that is the only one around, because you weren't game to turn it a bit more. Nev

 

 

[JerzyGeorge]

That decision at that height is good and confining your areas to 30 degrees or so off runway heading and using the into wind direction of turn if possible, is pretty standard stuff, proven to be the best advice generally . YOU did the right thing.No two situations are the same though . IF you have thought about where you will go prior to opening the taps. You are even better prepared. IF you have a very long runway you may want to lose height quickly and land on the remaining runway available. This may require taking full flap and diving the height of quickly, rather than gliding at best speed and a more positive flare. Regarding those stall speed variations with bank angle.... In a tight situation you are not going to be looking much at the airspeed, so practicing steep gliding turns gives you a knowledge of your planes nose down attitude needed and some awareness of the stick position, should be trained into you.. You don't want to bang into a large tree trunk that is the only one around, because you weren't game to turn it a bit more. Nev

Thanks Nev for positive comments The runway was behind my tail ( it was after touch and go) and yes I was lining it up into wind for landing , during one of the practice engine failures I did turn with the wind and lost so much altitude and distance that could not come back into runway. Because it was not a real thing I landed under power but it taught me a lesson- turn into wind rather with the wind. It was some time ago , perhaps 4-6 months ago before I really needed. And yes my focus was to find acceptable landing area and nose - horizon ( speed) . George

 

 

[facthunter]

The mainreason the into wind is preferred is because of the reduced landing speed. IF you are going to hit something do it as slow as possible.

 

On a similar tack if in a glider or a pusher and you are going into a wire fence groundloop into wind so you don't cut your head off. It's practically impossible to turn the other way with rudder if there is much crosswind and you have no power. Nev

 

 

[JerzyGeorge]

Thanks a lot Nev . You have a lot of experience I think I can learn a lot from you . It is amazing how much value is in this discussion like this. George

 

 

[cscotthendry]

IF you have a very long runway you may want to lose height quickly and land on the remaining runway available. This may require taking full flap and diving the height of quickly, rather than gliding at best speed and a more positive flare. Nev

Interesting scenario.

If you thought that with a bit of a squeeze you could get it back on the runway, (in the same direction) would you consider using a sideslip to lose height rapidly?

 

 

[facthunter]

As long as that technique suited the plane and you are competent to do it to low level, why not? You are trying to get rid of the aircrafts energy. The steep descent has to be managed safely like all things. Nev

 

 

[johnm]

Good point facthunter. Would a glider nose pod fail at a wire fence ?think if you were in one or a pusher plane a wire fence would be something to avoid - with a tractor plane probably could be a good thing to slow you down ?