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  #11  
Old 04-07-2010, 06:00 AM
pierre smith's Avatar
pierre smith pierre smith is offline
 
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Default Thanks, Gary...but.....

....don't you think that a wider gliding pattern makes it more difficult to judge your descent path and touchdown point?

In the event of a real engine failure, I'd use whatever bank angle is necessary to get the job done....standard rate turn or no,

Best,
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  #12  
Old 04-07-2010, 10:13 AM
gereed75 gereed75 is offline
 
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Pierre, Yes and no. The idea is that it is a standard pattern, flown the same way each time, so that once you intercept the pattern (hopefully by adjusting your glide into Hi key) you now have known parameters to fly to get you down at your intended point of landing.

Those parameters would never change in a perfect, no wind situation. In real life, you will have to adjust - because you hit Hi key a bit high, or low, or the wind is blowing hard, or whatever. But the beauty is those adjustments are made in a logical way against known aircraft performance.

Let's say you hit high key 300' high - you can slip a bit during the turn to hit low key right on. If you slipped too much and hit low key 150' low, you will increase you AOB a bit to tighten the pattern, or if necessary hold flap extension until 50' AGL. Again, all measured adjustments to hit standard checkpoints around the pattern. Once you intersect the pattern, it is back to a known standard flight path, that if flown in the standard way, will get you into the field.

Certainly, when it comes right down to it, your final statement is correct, your gonna do what you have to do to make the field.
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  #13  
Old 04-14-2010, 07:32 AM
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olyolson olyolson is online now
 
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Default Idle Mixture?

[quote=AlexPetersonI pull the throttle to idle and pull the mixture all the way back (I do keep my hand on it the whole time until short final, so that I don't forget it is out in case I need power!). [/QUOTE]

Why pull the mixture to idle? Seems like it's a setup for an uncomfortable situation if there's any distractions. You are asking for trouble if you don't get the mixture back to rich on a go around. I know it's good to discuss different ideas on the ground but what's the rational for the idle mixture? I'm not the most experienced RV driver so perhaps I'm missing something here.
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  #14  
Old 04-14-2010, 06:42 PM
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AlexPeterson AlexPeterson is offline
 
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Quote:
Originally Posted by olyolson View Post
Why pull the mixture to idle? Seems like it's a setup for an uncomfortable situation if there's any distractions. You are asking for trouble if you don't get the mixture back to rich on a go around. I know it's good to discuss different ideas on the ground but what's the rational for the idle mixture? I'm not the most experienced RV driver so perhaps I'm missing something here.
Emergency landing practice in itself creates a higher risk situation for that flight than not doing it at all. However, it will greatly reduce risk if an actual engine failure occurs. If you aren't comfortable pulling the mixture, don't do it. It affects glide, but not by a whole lot.

I pull the mixture back for two reasons - one, it removes all power, and two, it prevents a bunch of after firing in the exhaust pipes (FI engines tend to do this). My hand stays on the mixture until short final, then mixture full rich, hand back on throttle. No big deal.
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  #15  
Old 04-14-2010, 07:04 PM
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Kevin Horton Kevin Horton is offline
 
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Quote:
Originally Posted by olyolson View Post
Why pull the mixture to idle? Seems like it's a setup for an uncomfortable situation if there's any distractions. You are asking for trouble if you don't get the mixture back to rich on a go around. I know it's good to discuss different ideas on the ground but what's the rational for the idle mixture? I'm not the most experienced RV driver so perhaps I'm missing something here.
There may be a significant difference in glide performance between engine at idle, and engine not running but prop windmilling. Doing practice with the engine idling will have you well prepared for the day when the throttle cable breaks and the engine is still running, but stuck at idle. But that is not the failure case that most people are worried about. If you are more worried about being ready to handle engine failure, then someday you should find out how the aircraft glides with the mixture at OFF. You obviously should pick the right time and place to do this testing with mixture OFF, but you really ought to be mentally prepared to handle an engine failure on every flight.
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  #16  
Old 04-14-2010, 09:39 PM
David-aviator David-aviator is offline
 
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Quote:
Originally Posted by Kevin Horton View Post
There may be a significant difference in glide performance between engine at idle, and engine not running but prop windmilling. Doing practice with the engine idling will have you well prepared for the day when the throttle cable breaks and the engine is still running, but stuck at idle. But that is not the failure case that most people are worried about. If you are more worried about being ready to handle engine failure, then someday you should find out how the aircraft glides with the mixture at OFF. You obviously should pick the right time and place to do this testing with mixture OFF, but you really ought to be mentally prepared to handle an engine failure on every flight.
Being mentally prepared to handle an engine failure on every flight is a given, Kevin, as you well know in your business. As power is pushed up for take off, if it isn't on your mind you should not be doing it.

The thing that gets pilots in trouble more than anything else is not expecting an engine failure or if it does happen, not doing the right thing. Sometimes the totally unexpected happens like Olie's Viggen pitching up when the engine failed. He instinctively rolled the machine into a modified split S and pulled out just before it hit some trees. How do you practice something like that? Olie is alive because his brain was plugged in that day.

So how do we keep our brain plugged in? The problem I have with practicing scenarios is that when things go wrong for real, they seldom fit what has been practiced. Does that mean you won't be prepared when it happens? Not necessarily.

Good preparation is wrapped up in a mental exercise as you are flying along. Is that field attainable? What is the surface wind right now? Wow, look at all those power lines. That golf course would work. Man, this is a dumb route, nothing but houses, etc, etc, hope the engine keeps purring until they are gone. This type of thinking is an absolute must in a single engine airplane. In the multi engine world, its all about dealing with the failed engine and pressing on. Here it is where do I crash. We fly over areas every day that provide no good place to land, that's the calculated risk of what we do. Many airports are surrounded with homes or businesses and some guys here live in the mountains.

Ok, so is it good idea to practice gliding without power? Statistically, it is not. The feds decided long ago pulling an engine on a check ride, whether it be a single or twin causes more grief than it is worth. Practicing it can be just as questionable. But if it feels good, I guess it is ok. I know for a fact having landed twice without power, you instinctively fly the airplane whether the engine is running or not. Your adrenaline will get you there and you really won't notice anything different except there is less noise. In one case it was about 45 seconds to ground contact and all that mattered was don't stall the airplane. In the other it was from 10,000 feet, no thought if high key or low key, just knew it was too high so did another 360 in tight figuring to put it down some where near the selected spot and it all worked out. As it turned out, it was on the numbers at the airport in Auburn, Alabama.

I practiced a high key approach in the RV last week with a 20 knot breeze. I would have crashed short of the runway due to extending the flaps too soon going into the headwind. That approach was in the bag but the wind queered it. I learned something - like don't extend flaps until the field is really made.
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  #17  
Old 04-15-2010, 01:17 AM
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rvmills rvmills is offline
 
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Quote:
Originally Posted by pierre smith View Post
....don't you think that a wider gliding pattern makes it more difficult to judge your descent path and touchdown point?

In the event of a real engine failure, I'd use whatever bank angle is necessary to get the job done....standard rate turn or no,

Best,
Pierre,

At first blush, a 1000' hi key seems a bit low...but not having been there, I sure can't say it is. What angle of bank did it take to make it work? I'm pretty sure that in my clipped-wing machine it'd be tough to make that work without really wrapping it up, but your 10 likely glides much better. I'm going to go play some and see what feels good, and will report back.

I think Gary said it well...as you practice it, I'd work to establish hi key/low key altitudes that allow a fairly comfortable angle of bank and a consistent pattern size and track as the baseline. Done well, it won't take up a lot of real estate, nor will it be a radical maneuver at all, but quite smooth and predictable...actually kinda fun (to practice...the real deal would take the fun out of it for sure...but even then, if practiced, it'd be familiar territory).

By comfortable angle of bank, I don't mean one that takes you well away from the field (I understand your concern there) but rather one that allows some margin for shallowing or steepening the turn to correct the flight path for wind, without having to really wrap it up to make the field. If your hi key is so low that it takes 45 degrees AOB to make it work, then you don't have much to work with if you have a howling x-wind that blows you away from the field in the turn, or a really big headwind on final. I agree with you that, in a real-deal, you do what it takes to make the field, and I also know you are very comfortable with steep banks low to the ground.

A good baseline may be standard rate, or 25 deg or 30 deg. That's something we can each determine for our aircraft, as well as the altitudes that work best for hi and low key. But if you start a bit higher and find the AOB and flight path that make it to your spot consistently, you have a great pattern that will work anywhere, like on a X-C, when you may not know the real winds until you are in the pattern...it just gives you a little margin for error.

With that as a baseline, you can then try lower hi keys to see what you can do if you can't hit high key at your normal altitude. At some lower point you would likely just make the call to make the straight in, and slip it as necessary. You can also simulate coming into hi key at various angles off, or coming into low key from 180 out (on downwind), or hitting the 90 from a base entry, or straight in. The gist of that is that you can make a judgement call as to whether, with the altitude you have, you can hit a point in the pattern from any angle and make the field...and if not, you can make the early call to find a differnt landing site, and not try to stretch the glide and get in trouble.

Just some thougts...nice work testing it out, and good discussion!

Cheers,
Bob
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  #18  
Old 04-15-2010, 11:54 AM
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olyolson olyolson is online now
 
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Default Practice engine-outs

Practice engine failures are a great idea and one we should practice for sure. BUT you guys that are pulling the mixture to OFF and letting the engine quit are asking for trouble. What if the engine doesn't restart and you mess up the pattern (ie: bad wind correction/energy state etc) and plunk it in a field and do some damage (or worse)? Is it worth it to have to fix/replace your airplane? And how gonna explain that to the FAA: "Yes officer, I intentionaly shut off the engine in flight at low altitude because I'm a supremely gifted aviator and knew I could make the runway". I don't think this is a good idea to be spreading around, especially since a lot of inexperienced pilots read this forum and may have to start doing "some of that pilot shi...." because they read that it was OK to do it that way on the Forum. If you want to do it with your airplane that's your right and if you feel you need to shut off the engine for more realistic training that's your call. I've done a lot of SFOs (simulated flameouts) in the F-16 but in the RVs we don't have the option in most cases to do a "nylon approach" if we screw up the pattern (unless of course you always wear a chute). But then again, we never actually shut off the engine either.
Not trying to be a party pooper here but with 14,000+ hours I have some things in my bag of tricks to stay safe and this manuever ain't one of 'em. As Dave Domeier says (and he's a pretty smart guy) "IMHO the training experience is not worth the potential for the engine to not restart".
Food for thought........
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Last edited by olyolson : 04-15-2010 at 05:00 PM.
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  #19  
Old 04-15-2010, 02:22 PM
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pierre smith pierre smith is offline
 
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Default Agreed, Oly....

...throttle back and idling is close enough for me. What can be done is to pull the PROP control all the way out for coarse pitch and a greater glide. It'll go coarse even with a windmilling prop if there's oil pressure,

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  #20  
Old 04-15-2010, 03:07 PM
TSwezey TSwezey is offline
 
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If you must practice a true engine out then do it on a 10,000 ft runway. If you can't land on a 10,000 ft runway with a dead engine I would suggest some training or another sport.
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