Canyon Turns

Robert Moore wrote:

Yep! We fought this battle for about two weeks last year.
There were two groups, one was the slow down and use flaps
with a shallow angle of bank and the other group (me) quoting
the aerodynamic textbook solution of flying at maneuver speed
and using about 75 degrees angle-of-bank.

Well, I'm almost certainly going to be at max angle of climb by the time I decide
I need to turn around, so maneuvering speed is out of the question. I'll be starting
my turn with 24 degrees of flaps at 70 mph.

George Patterson
Battle, n; A method of untying with the teeth a political knot that would
not yield to the tongue.

That "mathematically correct" minimum radius turn, at the load factor limit
(3.8 g, 74.7 deg bank) at Va, is not realizeable in practice. For the Cessna
172 I once calculated you'd have (I forget the altitude and gross weight),
under those circumstances, a rate of descent of about 3400 fpm. Unless the
canyon's narrowing AND the floor's rising (relative to your flight path),
you might be allowed some descent in the few seconds of the turn, but not
THAT much!

John.

--
John T Lowry, PhD
Flight Physics
5217 Old Spicewood Springs Rd, #312
Austin, Texas 78731
(512) 231-9391

"G.R. Patterson III" wrote in message
...


Robert Moore wrote:

Yep! We fought this battle for about two weeks last year.
There were two groups, one was the slow down and use flaps
with a shallow angle of bank and the other group (me) quoting
the aerodynamic textbook solution of flying at maneuver speed
and using about 75 degrees angle-of-bank.

Well, I'm almost certainly going to be at max angle of climb by the time I
decide
I need to turn around, so maneuvering speed is out of the question. I'll
be starting
my turn with 24 degrees of flaps at 70 mph.

George Patterson
Battle, n; A method of untying with the teeth a political knot that
would
not yield to the tongue.

This is based on my experience flying a small, single engine, GA plane
around Colorado and Idaho.

From my experience, you usually wont be at manuevering speed for a
canyon turnaround, because you are trying to climb. You can't climb
fast enough to outclimb the terrain. You are trying climb out
somewhere around Vx to Vy.

I suppose it all depends on what you are doing. The times when I have
NEEDED a small radius turn I was in a narrow canyon, flying a pattern
to an unimproved strip. In another case, I went up a canyon that ended
at a mountain, not at the airport. (I went up a dead end canyon,
mistakingly thinking there was an airport there.) It was hot, bumpy, I
was heavy, and I was slow.

I suppose if you are flying high speed manuevers in canyons and want
to turn around, then turning at Va might be an option. But that is not
how most of us fly in the mountains. Most of us are either climbing
out of an airport, and can't outclimb the terrain, or are headed up a
canyon, it's not working out due to steep terrain and downdrafts, so
we have to turn around. We are flying at speeds closer to Vy and Vx,
not at Va. If I could get Va, I'd pull up until at Vx and might not
need to turn around.

Most small planes will barely climb at Va. My Husky has a Va of 94. At
gross weight on a hot day, I would not be climbing much at that speed,
maybe 50-100 fpm. And a Husky climbs well (but not at Va it doesn't).
The Cessnas I have flown are similar (though most don't climb as well
as my Husky).

If you are talking about flying fighter jets in the mountains, zooming
around the canyons, you have LOTS of power, then I would suspect it is
different. Get enough power, your climb problems are over, just go
straight up!

Robert Moore wrote in message .7...
"Marc Lattoni" wrote

Today we did canyon turns, not at 30, not at 45 but more than 45
degrees. Sort of standing the airplane on its wingtip as we turn.

Yep! We fought this battle for about two weeks last year.
There were two groups, one was the slow down and use flaps
with a shallow angle of bank and the other group (me) quoting
the aerodynamic textbook solution of flying at maneuver speed
and using about 75 degrees angle-of-bank.

Quoting from "Aerodynamics For Naval Aviators":

"The aerodynamic limit of turn radius requires that increased
velocity be utilized to produce increasing load factors and
greater angles of bank"

"The maneuver speed is the minimum speed necessary to develop
aerodynamically the limit load factor and it produces the
minimum turn radius within aerodynamic and structural limits."

Bob Moore

The 55 degree steep turn is a required commercial maneuver. As you have
noted, it is harder than the 45 degree turn required of private pilots. It
must be maintained within five degrees of bank throughout the turn.

This is a *visual* maneuver. A lot of pilots try to look at the instruments
too much, especially the VSI. Nearly every student that I have seen who had
trouble with the 55 degree steep turn was looking at the VSI, but they don't
all realize that they are doing this. You would be amazed at how much better
they all do when I cover the instrument.

The best way to do this turn is to never look at the instruments at all.
Roll smoothly into a 55 degree bank and do not let the nose drop. You should
be able to see the slightest vertical movement of the nose against the
horizon. Let the horizon cut like a knife across the cowling -- don't let it
rise or fall in the least. Use whatever arm strength you have to hold it
there. When you roll out, the airplane will want to pitch up sharply. If you
have used trim to help you in the turn, be prepared for an even greater
pitch up moment. Anticipate this by gradually applying forward pressure on
the nose as you roll out. Again, watch the horizon on the cowling. Don't let
it rise or fall in the slightest.

The only instrument you want to even glance at is the attitude indicator. It
also will tell you whether the pitch is up or down, and confirm that you are
at the proper bank angle. Once you have confirmed that, don't look at it
again. It is not nearly as sensitive as watching the nose on horizon.

The only instrument you want to even glance at is the attitude indicator
[during steep turns]

IF the goal is to maintain altitude +/- 100 feet, how do you know you did that
unless you glance at the altimiter?

jOSE

--
(for Email, make the obvious changes in my address)

"Teacherjh" wrote in message
...
The only instrument you want to even glance at is the attitude
indicator
[during steep turns]

IF the goal is to maintain altitude +/- 100 feet, how do you know you did
that
unless you glance at the altimiter?


If your nose does not pitch up or down then you will maintain your altitude.
You can glance at the altimeter to after you have completed the maneuver to
see how you did.

C J Campbell wrote:
The 55 degree steep turn is a required commercial maneuver. As you have
noted, it is harder than the 45 degree turn required of private pilots. It

A "canyon" turn has nothing to do with a "required commercial maneuver"!
It is a last ditch manuver to get out a bad situation.

Altitude loss may be acceptable, if you have some excess to begin with.

If the canyon is narrow, start the turn as close to one wall as you dare,
about two wingspans. You should have been near the "updraft" wall before
you figured out that you need to turn around.

If you have some excess speed, first pull up into a zoom which gains
altitude, and bleeds off the speed. Canyons are usually wider higher up.

As speed decays to 1.2Vs, deploy ~15 deg of flaps, roll away from
the canyon wall to a 45-60 deg bank, use lots of rudder, dont
pull elevator until the nose drops to about 20 below horizontal.

Since you started the turn with the nose up (in the zoom), you will
be most of the way around by the time the nose has dropped.

Roll out parallel to your original course. You will feel a small
g force as you pull out of the slight dive; you can modulate the
pull out by controlling elevator back pressure.

Done this way, you will finish the turn over the center of the
canyon, where presumably the floor of the canyon is "deeper",
so you have more ground clearance.

Starting from an airspeed of ~100mph, I can turn my 182 around
in a horizontal space of about 10 wingspans, while gaining
100 to 200 ft of altitude. btw- I have practised this dozens of
times. My airplane is hangared about 10 miles from some very deep,
very long, very narrow glacier-cut canyons. Have you ever skiied
at Alta, UT? Ever flown Lake Clark Pass in AK?

MikeM
Skylane '1MM

Why the flaps? Seems to add a bit of complexity to an otherwise simple
wingover.

Shawn
"MikeM" wrote in message
...
C J Campbell wrote:
The 55 degree steep turn is a required commercial maneuver. As you have
noted, it is harder than the 45 degree turn required of private pilots.
It

A "canyon" turn has nothing to do with a "required commercial maneuver"!
It is a last ditch manuver to get out a bad situation.

Altitude loss may be acceptable, if you have some excess to begin with.

If the canyon is narrow, start the turn as close to one wall as you dare,
about two wingspans. You should have been near the "updraft" wall before
you figured out that you need to turn around.

If you have some excess speed, first pull up into a zoom which gains
altitude, and bleeds off the speed. Canyons are usually wider higher up.

As speed decays to 1.2Vs, deploy ~15 deg of flaps, roll away from
the canyon wall to a 45-60 deg bank, use lots of rudder, dont
pull elevator until the nose drops to about 20 below horizontal.

Since you started the turn with the nose up (in the zoom), you will
be most of the way around by the time the nose has dropped.

Roll out parallel to your original course. You will feel a small
g force as you pull out of the slight dive; you can modulate the
pull out by controlling elevator back pressure.

Done this way, you will finish the turn over the center of the
canyon, where presumably the floor of the canyon is "deeper",
so you have more ground clearance.

Starting from an airspeed of ~100mph, I can turn my 182 around
in a horizontal space of about 10 wingspans, while gaining
100 to 200 ft of altitude. btw- I have practised this dozens of
times. My airplane is hangared about 10 miles from some very deep,
very long, very narrow glacier-cut canyons. Have you ever skiied
at Alta, UT? Ever flown Lake Clark Pass in AK?

MikeM
Skylane '1MM

"ShawnD2112" wrote in message news:O634c.279$pA3.40@newsfe1-win...
Why the flaps? Seems to add a bit of complexity to an otherwise simple
wingover.

Shawn

Flaps lower the stall speed, which rises markedly in a steep
turn. You need all the margin you can get.
In a 172 the first 20 degrees of flap lower the stall the most, and
the last 20 is mostly drag. We do minimum-radius turns at 70 kts, 20
flap, 60 degrees of bank.

Dan

"MikeM" wrote in message
...

Ever flown Lake Clark Pass in AK?

I wouldn't classify that as a tight canyon. You could turn a C130 around in
there.

PJ