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  #121  
Old 05-19-2012, 07:51 PM
Captain Avgas Captain Avgas is offline
 
Join Date: Oct 2005
Location: Melbourne, Australia
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Quote:
Originally Posted by gereed75 View Post
Draw your own conclusions. I know mine - below 600 feet AGL, lower the nose and look for somewhere to land in front of the wings!
Gary, you're already ahead of the game now by knowing your "no-go" turnback altitude.

In the turnback maneouvre, procrastination is a killer. It results in the loss of critical altitude and an increase in the distance back to the airfield.

You, on the other hand, do not need to procrastinate about whether to turn back or not. You only need to glance at the altimeter and that instrument will make the decision for you instantly. If it reads 600 ft or above, you're going back to enjoy a beer at the hangar. Less than 600 ft and you're making the best of what lies ahead or to the side.

The ability to make an instant decision (by having a known "no-go" altitude) and having confidence in the outcome (by being proficient at the manoeuvre) are the keys to the successful turnback.
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Last edited by Captain Avgas : 05-19-2012 at 09:27 PM.
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  #122  
Old 05-20-2012, 07:36 AM
simpkinsona simpkinsona is offline
 
Join Date: Dec 2010
Location: Vacaville, CA
Posts: 167
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While 600 feet is probably safe in most situations, it is not safe in some. I took off at Big Bear california with a full load on a hot day, and there was no way I would be able to turn back to the runway at 600 feet. I think in situations like that you need to be thinking straight ahead as you climb and then look at your situation as you get higher, making a mental shift from straight ahead to turn around when you know you can make it. On that take-off I would have never made that shift, so would have landed straight ahead.

-Andy
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  #123  
Old 05-20-2012, 08:38 AM
johnny stick johnny stick is offline
 
Join Date: Dec 2008
Location: Los Angeles, CA
Posts: 301
Default So what do we do about it?

Ok so we know that the turn back is risky at best and very dangerous. Knowing this, there are two things I will now do on every flight:
1) either do a downwind departure, or at least a crosswind departure, so that I am stay near the airport while low and slow.
2) or have a place to go straight out

I fly from an airport buried in the city, so any off airport landing is dangerous for me or someone on the ground. After seeing the videos, reading the discussions, and having a friend have his last flight trying to turn back a Bonanza, no more straight out climbs for me, unless I am willing to put it down out there. The most important video for me was the 172 departure from a 4500' hard deck; landed short every time trying to make it back from 1000'.

Thanks for the discussion.
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  #124  
Old 05-20-2012, 01:38 PM
the_other_dougreeves the_other_dougreeves is offline
 
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Location: Dallas, TX (ADS)
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Quote:
Originally Posted by MauiLvrs View Post
Most of the time it is a mistake. (NTSB)

If it is a mistake, most of the time you won't make it. (NTSB)

Most of the time you won't make it!

Note that an argument can be valid, even if one of the premises is false
Flying is dangerous. (NTSB) Maybe its best to stay home on the couch?

Folks, the 180 return-to-runway or abbreviated pattern is like any other skill - you need to practice it if you have any hope of executing it correctly. Stalls, spins, VFR into IMC... you should practice these things, or your chances of making it is low.

Having said that, if you practice, and you make a decision about your alternatives if the fan quits before advancing the throttle, its not an exceptionally risky maneuver. We have plenty of pilots who kill themselves in stall/spin accidents on otherwise normal patterns, but I don't hear anyone calling for the abolition of the standard pattern (oops, "straight in to uncontrolled field" debate, anyone?).

Think about your decision heights in advance, keep the speed above your minimum approach speed and stay coordinated. Those three and practice will go a long way to keeping you flying another day.

I've only done 5 180s in the last year - two practice in the CT @ 500ft (my "standard" DH in the CT) and three in the glider (one unannounced as part of "first flight" reviews, one unannounced during a BFR and one practice; most of these at 250ft). Even so, I still feel a little anxiety when I hear the release pull, but training quickly takes over: Nose down, roll into the turn, yaw string / ball straight, check speed again, look for the runway, stay coordinated, speed, touchdown point, roll out, spoilers as needed, speed, touchdown point, speed, touchdown point.... you get the idea.

In my mind, the 180 is a basic airmanship skill that needs to be taught along with stalls and spins. If you show students what they can and can't do from an early "age", they won't fear the emergency and will instead react properly to it. We treat the "rope break" this way in our soaring club and I think we demystify the 180 this way.

Disclaimer: If you haven't practiced the 180 and don't know the limits of you and your airplane, don't try it.

TODR
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  #125  
Old 05-20-2012, 04:25 PM
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newt newt is offline
 
Join Date: Jan 2011
Location: Sydney, Australia
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Quote:
Originally Posted by RV7Ron View Post
Quote:
Bank Angle Stall Speed Increase (%)
0 deg. 49 knots 0%
35 deg. 53 knots 8%
45 deg. 59 knots 20%
60 deg. 71 knots 43%
75 deg. 97 knots 97%
It aggravates me that this kind of information is always used without the caveat...."this is only applicable if you are maintaining altitude...i.e., loading G's...and increasing AOA in the process"....although they do sneak in "because of loading." Ok, what does that mean?
I hate the term "stall speed." Speed at what weight? What load-factor? Are you balanced so that the stall speed is the same on both sides?

This table is better:


Bank angle Stall AoA AoA increase(%)
0 deg. 15 deg. 0
35 deg. 15 deg. 0
45 deg. 15 deg. 0
60 deg. 15 deg. 0
75 deg. 15 deg. 0

:-)

- mark
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  #126  
Old 05-20-2012, 04:38 PM
Ron Lee's Avatar
Ron Lee Ron Lee is offline
 
Join Date: Jun 2005
Posts: 3,275
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Quote:
Originally Posted by newt View Post
This table is better:


Bank angle Stall AoA AoA increase(%)
0 deg. 15 deg. 0
35 deg. 15 deg. 0
45 deg. 15 deg. 0
60 deg. 15 deg. 0
75 deg. 15 deg. 0
That tells me nada. I have no AoA indicator.
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  #127  
Old 05-20-2012, 04:52 PM
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scard scard is offline
 
Join Date: Jun 2005
Location: Cedar Park, TX
Posts: 3,156
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Quote:
Originally Posted by the_other_dougreeves View Post
Flying is dangerous. (NTSB) Maybe its best to stay home on the couch?

Folks, the 180 return-to-runway or abbreviated pattern is like any other skill - you need to practice it if you have any hope of executing it correctly. Stalls, spins, VFR into IMC... you should practice these things, or your chances of making it is low.

TODR
Ahhhh,, Thanks TODR. We've been doing the 180 "impossible turn" each and every weekend for many weeks now in the glider world at 200'. Come to find out, it is totally doable with lots of training. I've done a few days worth of practice of the maneuver in the RV in the past, but am looking forward to going back and seeing my progress after lots of good solid training and practice. Declaring the altitude and knowing for absolutely certain that that specific altitude with today's conditions is, and has proven to be, perfectly successful is almost liberating. If we could all just stop talking and go out and improve core piloting skills... I'm not ace at all, but we spend our weekends doing these things (today was over two hrs worth of approaches on an IFR flight plan) instead of looking at cows.
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  #128  
Old 05-20-2012, 05:36 PM
DanBaier's Avatar
DanBaier DanBaier is offline
 
Join Date: Mar 2009
Location: Rochester NY
Posts: 669
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Quote:
Originally Posted by newt View Post
This table is better:

Bank angle Stall AoA AoA increase(%)
0 deg. 15 deg. 0
35 deg. 15 deg. 0
45 deg. 15 deg. 0
60 deg. 15 deg. 0
75 deg. 15 deg. 0
Maybe...

When the rate of descent is constant, the angle of attack increases with bank. When the angle of attack is constant, the rate of descent is going to increase with bank. Can you add a column that shows the corresponding rate of descent with the increase in bank angle?

Dan
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  #129  
Old 05-20-2012, 05:38 PM
n5lp's Avatar
n5lp n5lp is offline
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Join Date: Apr 2006
Location: Carlsbad, NM
Posts: 1,912
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I have probably two or three dozen failures in gliders at low altitude (broken wire on winch launches). These have occurred anywhere from 15 feet to 1,500 feet or so, and normally they occur at an airspeed around 5 or 10 knots above stall. Often they have occurred at deck angles of around 45 degrees nose up. Other than the absolute need to react quickly; probably within two seconds, they are no big deal. Similarly, a rope break at 200 feet with an air tow, is no big deal and a turn around to land on the take-off runway is normally easy.

Gliders and RVs are both fixed wing aircraft but there are many differences, notably glide angle. RVs also differ greatly from other fixed wing aircraft like DA-20s and other glider like powered craft. Someone compared RV glide angles to factory airplanes like Cessnas. If I had the choice to do a low altitude turn around in my RV-6 or a Cessna 172, i would sure take the Cessna.

The fact that low altitude turn arounds can be done routinely in low stall-speed, high aspect-ratio aircraft, and that I have done them many times, will not influence me at all to try that stunt in my RV, which has a poor glide ratio, particularly at low speed, and a sink rate that increases greatly with constant airspeed bank angle.
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Last edited by n5lp : 05-20-2012 at 05:40 PM.
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  #130  
Old 05-20-2012, 07:20 PM
L.Adamson's Avatar
L.Adamson L.Adamson is offline
 
Join Date: Apr 2005
Location: KSLC
Posts: 4,021
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Quote:
Originally Posted by n5lp View Post
The fact that low altitude turn arounds can be done routinely in low stall-speed, high aspect-ratio aircraft, and that I have done them many times, will not influence me at all to try that stunt in my RV, which has a poor glide ratio, particularly at low speed, and a sink rate that increases greatly with constant airspeed bank angle.
I'm glad you brought that up...........because there is too many comparisons to gliders or lightly loaded wings being compared. Once again, I've seen a lot of spin ins with quarter scale R/C. Lightly loaded wings can make nice easy turns with a lot less altitude loss. With the heavy models, it either a high sink rate, or just figure that it will spin in, if you keep forcing it around........as it usually does. BTW --- I live next to an airport. There has been three unsuccesful 180 turn backs since I've lived here.

L.Adamson
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