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  #11  
Old 11-17-2019, 08:32 PM
Papa Papa is offline
 
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Quote:
Originally Posted by skylor View Post
Please don't try to make this a "turnback" discussion. That's not what this thread is about.

Skylor
Skylor my friend...my post was tongue-in-cheek, thatís why I put a smiley face in it. I certainly donít advocate using a split-s to return to the runway! But on a more serious note, if youíre trying to work out high and low key numbers as targets for an engine out approach, I would advise bumping them up a bit and giving yourself a long enough final so that you can kill any extra altitude with a slip or gentle s turns. You can fix being a little high (within reason), but if you error on the low side, there isnít a lot you can do to fix it!

Papa
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  #12  
Old 11-17-2019, 09:22 PM
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Pilot135pd Pilot135pd is offline
 
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Quote:
Originally Posted by rocketman1988 View Post
Hypothetically, imagine the NTSB report from an accident resulting from intentionally stopping an engine in flight even if it is over an airport...any guesses what it would say?
I know what it'll say, he'll never admit he did it on purpose, he'll just say the engine quit on its own.
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  #13  
Old 11-17-2019, 09:41 PM
rocketman1988 rocketman1988 is offline
 
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Default Exactly

Yep, it just quit...
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  #14  
Old 11-17-2019, 11:17 PM
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RV8JD RV8JD is offline
 
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Skylor, thanks for the data. Appreciate it.

As for the negative replies, remember - no good deed goes unpunished. Certain people just like to hear themselves type!
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  #15  
Old 11-18-2019, 12:32 AM
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skylor skylor is offline
 
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Default Safety Margin

Quote:
Originally Posted by Papa View Post
Skylor my friend...my post was tongue-in-cheek, thatís why I put a smiley face in it. I certainly donít advocate using a split-s to return to the runway! But on a more serious note, if youíre trying to work out high and low key numbers as targets for an engine out approach, I would advise bumping them up a bit and giving yourself a long enough final so that you can kill any extra altitude with a slip or gentle s turns. You can fix being a little high (within reason), but if you error on the low side, there isnít a lot you can do to fix it!

Papa
Yes, Iím aware of the need to add a bit of margin to these numbers. I actually rounded the altitude losses up slightly from the raw values and one needs a bit of margin to allow for wind effects and pilot performance variation. Thank you.

Skylor
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  #16  
Old 11-18-2019, 09:01 AM
rocketman1988 rocketman1988 is offline
 
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Default ...and

"...As for the negative replies, remember - no good deed goes unpunished. Certain people just like to hear themselves type!..."

Well you ought to be able to hear the typing when that engine doesn't start...
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  #17  
Old 11-18-2019, 10:06 AM
Vac Vac is offline
 
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Default SFO Practice

Skylor,

Excellent data and great idea for a thread.

I regularly practice SFO (simulated flame-out patterns). One of the things you noted was that you lost less altitude in a 45-degree banked turn than a 30 degree banked turn, which is a bit counter-intuitive; but physics isn't always intuitive! The most important thing is to have parameters for your airplane (altitude lost in a 180 and 360-degree descending turn, power off and airspeed and/or AOA references for L/Dmax and ONSPEED). One of the biggest factors is the type of propeller fitted. A light-weight, composite fixed pitch propeller may quickly stop in an actual engine failure as you slow to L/Dmax, which reduces drag. A metal prop will usually continue to windmill (unless power loss was the result of an oil system failure) unless the pilot wishes to intentionally stop it. A good ROT is to not bother with attempting to stop the prop at altitudes below 3-4K AGL unless you are very familiar with the technique to do so in your airplane. If the propeller is controllable, the pitch selected has a big impact on glide performance. And residual thrust factors in, practicing in IDLE is not the same as a true power condition; but it is certainly worthwhile practice nonetheless.

Another thing that may seem counter-intuitive is that it may be easier to consistently maneuver an airplane with a lower glide ratio--going down and slowing down simultaneously isn't as difficult and there is less time aloft reducing exposure to wind effects over time. The light weight, motor glider that I fly (160 HP fixed pitch RV-4) just doesn't want to quit flying, which means I have to apply malice of forethought any time I want to go down or, god forbid, go down AND slow down--wind is always a factor, even when it's light.

I find it's actually more challenging from an energy management perspective to fly an "A" pattern, because of the shallow bank angles involved and the need to compensate for winds aloft during descent:

https://youtu.be/vTJotyoBQWM

Although steeper bank angles and some G's are involved, I find the "B" pattern easier to fly consistently well since it reliably drops me off at a standard low key for my airplane. This pattern is just a 1080 steep spiral to 180 power off approach:

https://youtu.be/u4qKhgi32C8

I'm a fan of accurate AOA references, since the key performance AOA's I care about aren't affected by bank angle/G, weight or density altitude. It simplifies energy management. All I have to do is maintain desired AOA and make the sight picture look right--which is about as much cockpit math as my unfrozen fighter pilot brain can handle. You don't need specific bank angle parameters, just "more, less" or "whatever it takes." I'm also a fan of flying every approach (traffic permitting) as an idle 180 so I've got lot's of practice in a power off turn to 10-12" stable final, on parameters.

This, of course, is all technique, not procedure. The only requirements are to maintain sufficient energy and not lose control of the airplane--best to practice regularly using whatever technique suits you to develop consistent hoops to fly thru and sight pictures.

Great discussion.

v/r,

Vac
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  #18  
Old 11-22-2019, 11:05 AM
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Eddie P Eddie P is offline
 
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Good specific subject matter Skylor, thanks for sharing.

Love the videos VAC, very useful and your time in making them is apprecuated. I like your pattern B depiction. I'm also a glider pilot. I didn't train on gliders until I was already flying 747's, and it was a great antidote for over exposure to excessive resources in aviation. Learning these types of techniques and thinking proper energy management down low while targeting tight landing fields is thankfully something that comes easy to any "ready to learn" pilot with enough thoughtful (safe) introduction, exposure and practice. In an RV, SFO practice is great for fun and getting better at techniques involved. It's also highly beneficial to keep commonly used procedures anchored to real world needs. We may have to deal with a "SFO" weather we like it or not, when we are least ready to do so and with the least amount of excess mental capacity to come up with something not recently worked on. Having a few good anchor numbers to work with is an outstanding start to executing a real SFO when needed. I also use an old pilotage visual reference SA rule of thumb where my wingtip crossing an object on the ground dictates a safe "fly direct to" no wind glide distance, subject to energy bleed off when turning toward and using speed to make the turn, pulling to glide AOA, etc. Obviously a real SFO overhead arrival procedure can't be to a "direct to" chosen field but in any situation, there is a spectrum of useful techniques one is proficient in that get partially or fully employed along the way to arrive at a successful solution.
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