Are 'Single 180 Turn From Downwind to Final' and 'Stall-spin on Turnfrom Base to Final' mutually exclusive?

my $.02:

First, the beauty of the 360 "Overhead" pattern is that it makes it really easy to fly exactly the same pattern at ANY airfield. As long as you come up initial at the same speed, and pitch out at the same bank angle, you will end up at the same place on downwind (adjusted for x-wind, of course). The, you just configure, motor to the perch, and roll into your easy 180 turn to line up on final. Done well, it's one of the most satisfying maneuvers in aviation.

And it has the advantage of being a really quick way to enter the pattern, slow down, and land - useful for towplanes.

BUT - it's meant for relatively fast movers with bigger turn radius's; works fine in a Pawnee at 120 mph, no so good in a J-3 at 65 mph, and not at all in most gliders (yes I've tried).

So, for gliders, all that is really useable is the second half - the continuous 180 degree turn to final. As others mention, that is not what is normally taught, and has some limitations that need to be taken into consideration; the main one is that it has to be done from a low downwind, and it happens fast.

And that is why I think it is actually a useful skill to practice: If you end up low and tight, you should be able to fly a safe 180 (or 270, or 90) pattern and land out of it - because you don't have the option of going around!

Just realize that most other traffic will not be expecting it and fly accordingly.

In regards to you question about the military's track record - I don't have numbers but would bet an expensive bottle of whiskey that it's a LOT better than that of GA - after all a military pilot is better trained, flies more often, gets lots of check rides, etc. That being said, modern military jets are more susceptible to high-sink rate problems in the pattern that stall/spins; look up almost any T-38 accident and getting low and slow on final will pop up often. For a supersonic jet, it is really a dog when slow!

Kirk
66

On 7/29/2016 1:10 PM, kirk.stant wrote:

Snip...
So, for gliders, all that is really useable is the second half - the
continuous 180 degree turn to final. As others mention, that is not what is
normally taught, and has some limitations that need to be taken into
consideration; the main one is that it has to be done from a low downwind,
and it happens fast.

I don't comprehend why a circle-from-downwind-to-final landing pattern in a
glider "...has to be done from a low downwind, and it happens fast." I
understand it CAN be done that way, but not why it MUST be done that way.

If Joe Glider Pilot is aiming to produce a threshold landing directly from the
180-degree turn, I suppose an overall lower flight path compared to the case
where he seeks to achieve the same "no straight final leg" threshold landing
directly from the base-to final turn would be the case, simply because the
latter/"tangencies-to-the-circle" flight path pattern would be longer due to
the "uncut corners," and hence the "rectangular path" pattern has greater
distance over which spoilers can be modulated. (The preceding scenario assumes
a "normal downwind offset distance;" the closer in the final, the less
additional distance flown, of course.) But if the goal is "simply" to hit a
pre-selected landing spot on a runway, he can also do "the circling thing" to
final, rolling out short-of and "normally above" the runway onto his final
approach path...which is what all of my "circling patterns" sought to achieve.
IOW, my circling-to-final in the HP allowed me to be able to use less bank
angle-per-unit-time (aka lower roll rate/stick forces) to a high, straight,
final approach path; I wasn't trying to emulate Joe Carrier Pilot in any way
beyond borrowing his 180-degree downwind-to-final turn. Likewise, the
microburst-influenced "fully circling pattern" described in another post, in
actuality, by design, resulted in a (very) short straight final.

Tangentially and as noted elsewhere, for whatever reason, I found no
difference in difficulty judging "howzitgoing" with respect to my glider's
status "in the descent cone" whether circling from downwind to final or using
separate, distinct, 90-degree turns to get there...if anything, the circle
seemed "more natural" to me..but then I preferred playing outfield to infield
as a kid! Either way, every pattern's goal: to arrive on a straight final
"somewhere on the high side" of my ship's theoretical descent cone.

Back to my original puzzlement...am I correct in believing "military approved"
circling approaches essentially do NOT include "a straight final" portion,
a-la the "immediately before touchdown" curving flight path understandably
employed by (e.g.) Pitts biplane pilots as a means of retaining over-the-nose
vision for as long as possible until the runway edges appear on either side of
the nose?

And that is why I think it is actually a useful skill to practice: If you
end up low and tight, you should be able to fly a safe 180 (or 270, or 90)
pattern and land out of it - because you don't have the option of going
around!

"Roger that!" on the go-around-impossible bit. (No mulligans in sailplane
landing patterns!) When I blundered into the sport, the concept of being
unable to "re-do a poor pattern" by going around was a
new/completely-foreign/ignorantly-scary concept to my "power-polluted" (in the
reading sense of things) brain. Upon becoming "stick-time/usefully familiar"
with the flight physics of sport sailplanes, the no-go-around reality quickly
mentally-morphed into "entirely normal and not a big deal"...so long as
reasonable and continuing assessment of "minding the approach store" was part
of the piloting package. It was immediately clear to me "an easily repeatable"
landing pattern was the primary tool in minding the store.

And "Roger that!" on being able to safely do (or more accurately, salvage, if
previous inattention/screwups have contributed, sardonic chuckle) low
patterns. Following "licensure," safely expanding one's flight envelope surely
is the name of the aviation game! So - where do I go to practice departures
from controlled flight *in* my landing pattern?

Bob W.

On 7/29/2016 4:19 PM, BobW wrote:
Back to my original puzzlement...am I correct in believing "military
approved" circling approaches essentially do NOT include "a straight
final" portion, a-la the "immediately before touchdown" curving flight
path understandably employed by (e.g.) Pitts biplane pilots as a means
of retaining over-the-nose vision for as long as possible until the
runway edges appear on either side of the nose?

It's been quite a long time, but as I recall, the roll out on final was
around 1/2 - 3/4 mile from touchdown and that goes pretty quickly in a
jet. The way I currently fly the glider, it's closer to 1/4 mile from
completion of the turn to the touchdown point. I try to make my final
approach about the same flight time (vs. distance). Years of practice
have made this pretty routine.
--
Dan, 5J

On Friday, July 29, 2016 at 5:19:53 PM UTC-5, BobW wrote:

I don't comprehend why a circle-from-downwind-to-final landing pattern in a
glider "...has to be done from a low downwind, and it happens fast." I
understand it CAN be done that way, but not why it MUST be done that way.

Because you are taking out the base leg - and the altitude and time spend exiting the first 90 degree turn, flying the base leg, then entering the second 90 degree turn to final. All this takes time and altitude so either you fly a tight, low downwind and 180 to final, or you fly higher and wider and use 2 90s (or 2 45s and a 90). That's assuming you want to use reasonable angles of bank, not a real shallow 180 turn.

Back to my original puzzlement...am I correct in believing "military approved"
circling approaches essentially do NOT include "a straight final" portion,
a-la the "immediately before touchdown" curving flight path understandably
employed by (e.g.) Pitts biplane pilots as a means of retaining over-the-nose
vision for as long as possible until the runway edges appear on either side of
the nose?

No, it is based on rolling out on final at a comfortable distance from the threshold to allow for the final lineup and xwind correction. In jets it was about 1 mile out, in a glider it can be closer but you still want a comfortable final. The old "continuous turn to touchdown" was used by WW2 fighters (and Pitts', BTDT!) where you couldn't see the runway over the nose on a straight final. But it works nicely in a glider if your front seat passenger has big hair! ;^)

In our sport you take whatever pattern entry you can and should be able to safely land. Yesterday I was working a weak thermal just off the end of our club's runway - I had notified ground ops where I was and could see that there was no conflicting traffic, and used the opportunity to work on low save/landout procedures - which didn't work so I just rolled out at 500' or so and landed straight ahead, rolling up to the clubhouse. No standard pattern, but good training, I think. Some may disagree, and that's fine. I've had to do the same in real landouts and I like practicing non-standard approaches in a safe environment (I was watching the pattern and could break out and land at any time if conflicting traffic appeared). Perhaps that is from military training where you often practice emergency procedures in the air - watch F-16s doing SFO (simulated flame out) approaches sometime - there is an exciting way to land!

Kirk
66