Mountain Doctor wrote:Most important determinate of turn radius is speed. The slower the tighter at any given angle of bank. This is true if you make a level, 2D turn. If the terrain allows you to accept a descent in the turn, you can tilt the plane of the turn radius into 3D space, and shorten the horizontal aspect.

Stall speed is related to angle of bank. Only in a level altitude turn, and only because to maintain airspeed and altitude at angles of bank, we have to increase the load (g) on the wing. At +1g, the wing doesn't care if its level, in a bank, or upside down - it'll stall at the same airspeed, and always the same AoA.

So, slowest safe speed (I use 60 MPH) , partial flaps if called for (I use 24*) , reasonable but not extreme bank angle (I use 45*) , and allow altitude loss if terrain permits. This lowers AOA and further increases stall speed.I think this is an accidental typo, but lowering AoA doesn't change the stall speed. The wing will still stall at the same AoA, but by allowing the descent you've reduced the load (g) on the wing and reduced your stall speed at your given angle of bank.

You've said some things here that are correct if given a little more context, and incorrect if given another context. I cleaned it up for you!

So, perhaps a little humour for this thread...

Anybody that has closely followed my posts (anybody?) knows that I'm a very new pilot. I live and fly in very mountainous terrain. I'm pretty much committed to surviving the first year so I'm flying cautiously and spending as much time on dual instruction as I did before I got my ticket.

A week ago we decide to take our second solo (just the two of us in our own plane) flight from Squamish up to Princess Louisa Inlet and Chatterbox Falls. I'm not smart enough to post a picture, but it is worth a google. Gorgeous terrain, about 40 miles from home by air but incredibly remote by all other standards.

We cleared the intervening pass at about 5000' and began our descent toward the inlet, planning to fly up the channel at 1000' and do an orbit over the falls. All of a sudden, all of the reading I've done on box canyons started replaying in my head. The area is definitely confined, with granite walls giving way to 8000' peaks in short order. I could see the "New pilot augers in on second solo flight" headlines so I aborted the mission and did a flyover so high it was hard to tell if we were looking at Chatterbox Falls or a column of snow. My wife flies a Citation Sovereign for a living and hasn't flown a single engine piston for 15 years, so she is even more terrain adverse than I am.

We got back home and I called my favourite instructor to tell him what happened. As luck had it, he was wrapping up for the day so he suggested we fly back and check it out from a lower level.

Long story short, we went into the inlet at about 1500' and 110mph. He demonstrated that a 30 degree level turn with no flaps, starting from a comfortable distance from terrain would take up a little more than half the room available.

I've been back there three times since. My spatial awareness is improving and I now see that I have a ton of room (at a reasonable speed) but I still have to remind myself that I've done it before and concentrate on not pulling back like a maniac in the turn. I went out last night and spent an hour trying ever-tightening turns up against terrain. I'm re-reading Contact's book (third time now) and stuff that I couldn't grasp before is starting to make sense. I'm going to share the book with my instructor and see if he can teach the energy management turns.

albravo you are doing great, is good to have fear,good to ask lots of questions, good to ask your instructor to take you up ,and good to go practice and practice.

Once step at a time, do not hurry, lots of practice and as an old pilot friend told me when I started to fly, be afraid of everything!

albravo wrote:So, perhaps a little humour for this thread...

Anybody that has closely followed my posts (anybody?) knows that I'm a very new pilot. I live and fly in very mountainous terrain. I'm pretty much committed to surviving the first year so I'm flying cautiously and spending as much time on dual instruction as I did before I got my ticket.

A week ago we decide to take our second solo (just the two of us in our own plane) flight from Squamish up to Princess Louisa Inlet and Chatterbox Falls. I'm not smart enough to post a picture, but it is worth a google. Gorgeous terrain, about 40 miles from home by air but incredibly remote by all other standards.

We cleared the intervening pass at about 5000' and began our descent toward the inlet, planning to fly up the channel at 1000' and do an orbit over the falls. All of a sudden, all of the reading I've done on box canyons started replaying in my head. The area is definitely confined, with granite walls giving way to 8000' peaks in short order. I could see the "New pilot augers in on second solo flight" headlines so I aborted the mission and did a flyover so high it was hard to tell if we were looking at Chatterbox Falls or a column of snow. My wife flies a Citation Sovereign for a living and hasn't flown a single engine piston for 15 years, so she is even more terrain adverse than I am.

We got back home and I called my favourite instructor to tell him what happened. As luck had it, he was wrapping up for the day so he suggested we fly back and check it out from a lower level.

Long story short, we went into the inlet at about 1500' and 110mph. He demonstrated that a 30 degree level turn with no flaps, starting from a comfortable distance from terrain would take up a little more than half the room available.

I've been back there three times since. My spatial awareness is improving and I now see that I have a ton of room (at a reasonable speed) but I still have to remind myself that I've done it before and concentrate on not pulling back like a maniac in the turn. I went out last night and spent an hour trying ever-tightening turns up against terrain. I'm re-reading Contact's book (third time now) and stuff that I couldn't grasp before is starting to make sense. I'm going to share the book with my instructor and see if he can teach the energy management turns.

Princess Louisa--truly the most beautiful place on Earth. Erle Stanley Gardner (of Perry Mason fame) probably said it as well as anyone: "There is no scenery in the world that can beat it. Not that I’ve seen the rest of the world. I don’t need to, I’ve seen Princess Louisa."

The first time I saw her was in the evening, in a slight drizzle, and I was so awe-struck that I couldn't speak--and for me, that's really something! It's a place that you really should stay longer than just going in and coming back out, because every hour brings a difference--sort of like seeing a beautiful woman who has changed her clothes and make-up hourly. I was so impressed that I became a life member of the Princess Louisa Society. I promised I would come back, and I have.

She's only accessible by boat or airplane, and the Inlet is large enough to safely land a seaplane, in addition to being wide enough to easily turn around. I'd be more concerned about PL's weather than the amount of room, because I've seen it change from really good VMC to very low clouds in minutes.

I have two pictures that I took that first time, that I've had enlarged and framed, hanging on the front room's walls, of PL and Chatterbox Falls. They're a constant reminder that I've been privileged to be there.

Cary

Good story, allbravo. Next time you're out, if you've never done this, slow down and throw out second notch of flaps and do a 360 at about 65-70mph, 25 deg bank or so. The turn radius is impressively tight. I like to observe stuff on the ground in that config if I'm interested in reconnoitering something.

Maybe we're so deep into this thread that it's already been mentioned, but the canyon turns discussed (at least by Yoda) seem to assume plentiful altitude and/or straight and level flight while encountering the need to reverse course. But not all scenarios are like that.

Years ago I had an instructor put me in a scenario where I was landing an airstrip like Wilson Bar, Idaho. The premise was that I turned a blind corner to line up on short final and a huge tree had fallen across the middle of the one-way strip, unavoidable to hit if I was to land, but no way to go around.

From 55 mph, full flaps, he had me go full throttle, pitch for climb at 70, and execute a climbing 180. The force to overcome the trim required some serious pushing, but the turn radius was impressively tight. I suppose one would have to make the decision based upon the width of the canyon as to whether that maneuver was prudent vs just hitting the tree and damaging the gear/flipping. Could hurt less than stall/spin.

Now in the real world, that scenario is stupid. You always can recon the strip for such hazards.

Unlike stall proficiency, energy management turn proficiency is useful at any AGL altitude.

If on the deck, as in crop dusting or near the ridge in the mountains, the zoom up from cruise to near stall provides some vertical space. The valley, in the mountains, generally provides lots of vertical space.

This vertical space allows us to safely allow the nose to go down normally in the turn.

Again, it is a hard truth but normal is the nose going down in the contact turn. The airplane, for safety consideration, is designed that way. The 1g turn is safer than any load factor turn except the standard rate turn in instrument flying.

I keep harping on this truth, not to win an argument (it won't) but to save lives (it has, it will.)

51C170, I had an Acer Notebook when you posted your great spray run videos and couldn't run them. I now have this 750 SHP smartphone. I was going back through this thread and viewed them.

Thanks for the excellent representation of how energy management turns can safely be used to reverse course quickly and safely from five feet AGL with a significant load. How many gallons were you carrying?

CamTom12 wrote:

Mountain Doctor wrote:Most important determinate of turn radius is speed. The slower the tighter at any given angle of bank. This is true if you make a level, 2D turn. If the terrain allows you to accept a descent in the turn, you can tilt the plane of the turn radius into 3D space, and shorten the horizontal aspect.

Stall speed is related to angle of bank. Only in a level altitude turn, and only because to maintain airspeed and altitude at angles of bank, we have to increase the load (g) on the wing. At +1g, the wing doesn't care if its level, in a bank, or upside down - it'll stall at the same airspeed, and always the same AoA.

So, slowest safe speed (I use 60 MPH) , partial flaps if called for (I use 24*) , reasonable but not extreme bank angle (I use 45*) , and allow altitude loss if terrain permits. This lowers AOA and further increases stall speed.I think this is an accidental typo, but lowering AoA doesn't change the stall speed. The wing will still stall at the same AoA, but by allowing the descent you've reduced the load (g) on the wing and reduced your stall speed at your given angle of bank.

You've said some things here that are correct if given a little more context, and incorrect if given another context. I cleaned it up for you!

Thank you. Your elaborations are helpful and appropiate.

So, I've been playing with all the information in this thread. I took an instructor out for some practise. His version of the energy management turn was somewhat different from Contact's, so I concentrated the lesson on the traditional level steep turns and turns where I let the nose drop.

I think I understand correctly that unloading the wing by letting the nose drop allows for steeper bank angles but the benefit of a steeper angle of bank seems to be offset by the fairly rapid rise in airspeed and corresponding greater turn radius.

As soon as I let the nose drop I feel like I'm getting too fast and my turn radius is increasing. Close against terrain I feel particularly unnerved because a turn radius sufficient to continue avoiding terrain is impacted by the increasing speed.

Is the answer to start the turn slow enough that the increase in speed and radius are within reasonable bounds?

Mountain Doctor wrote:

CamTom12 wrote:

Mountain Doctor wrote:Most important determinate of turn radius is speed. The slower the tighter at any given angle of bank. This is true if you make a level, 2D turn. If the terrain allows you to accept a descent in the turn, you can tilt the plane of the turn radius into 3D space, and shorten the horizontal aspect.

Stall speed is related to angle of bank. Only in a level altitude turn, and only because to maintain airspeed and altitude at angles of bank, we have to increase the load (g) on the wing. At +1g, the wing doesn't care if its level, in a bank, or upside down - it'll stall at the same airspeed, and always the same AoA.

So, slowest safe speed (I use 60 MPH) , partial flaps if called for (I use 24*) , reasonable but not extreme bank angle (I use 45*) , and allow altitude loss if terrain permits. This lowers AOA and further increases stall speed.I think this is an accidental typo, but lowering AoA doesn't change the stall speed. The wing will still stall at the same AoA, but by allowing the descent you've reduced the load (g) on the wing and reduced your stall speed at your given angle of bank.

You've said some things here that are correct if given a little more context, and incorrect if given another context. I cleaned it up for you!

Thank you. Your elaborations are helpful and appropiate.

Glad I could help, Doc!

Albravo,

Think energy management. What can be done with too much airspeed and not create load factor? Airspeed is altitude. Trade cruise kinetic energy for altitude by pitching up wings level. Now start the turn by banking enough to insure getting the nose around before impacting the ground, now further down there. Hold no back pressure except in a true wingover (generally not necessary but plenty nose down if needed.) Use lots of rudder to get the nose around. Unless you practice 45 degree Dutch rolls you are probably not using enough rudder in the direction of the turn to get the nose around quickly. Altitude is airspeed. When the nose comes on target (points well down at the bottom of the canyon way down there), level the wing first and then pull up. Pull up not just to level but to zoom climb back to near entry altitude. Airspeed is altitude.

In the pull up to start the energy management turn, we get only as slow as we are comfortable with. With practice and for turns to near targets, that will be near stall. The more we bank, the further down the nose will go naturally and the faster speed will be regained.

The high speed dive you encountered was due to no pull up to slow down and gain altitude. When at high DA with low powered airplanes (near ceiling), we are already pretty slow just to maintain altitude. Just bank as much as needed to nail the bottom of the canyon and let the elevator go limp. You have started slow enough to prevent the high speed dive.

Keep at it. With time the energy management turn can become our conventional turn. When that happens, no extreme fear of flying up the wrong canyon.

Refer to recent Contactflying with contact flying posts. If your instructor will put up with a loud little man in the back seat, I'll come up and fly with you and him up front.

Contact

Summary:

I agree with most instructors here that it is best to learn a new technique dual with an instructor proficient in the technique.

That said, Motoadve has successfully worked through the energy management turn. He has progressed from the classic level turn with the stall warning on most way around through (first video,) to starting the turn level but allowing the nose to go down enough to turn the stall warning off (second video,) and finished with a classic energy management turn in the last video. He didn't pitch up as much as CC to make a tighter turn safe, but he didn't need to. He did allow the nose to go down as designed making the bottom of the canyon the target and leveled the wing before zooming back up a bit.

Pretty good, and safe, for just reading about it.