High Performance Flying Technique...safe?

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I'm writing this anonymously since I don't want to embarrass anyone. I own a Cherokee 235 with 2 other partners. One of the partners is in his mid 60's, and only has been a pilot for the last 5 years. He learned how to fly in a Warrior, and is comfortable in that plane. My other partner is also a flight instructor, and we (the flight instructor and myself) thought the 3rd partner was up to speed on the new plane. The flight instructor checked him off as good to go, but now it turns our older partner has reverted to flying the 235 like a Warrior, but in an unusual way. He is leaving the prop and mixture controls all the way forward for the entire flight, and only moves the throttle. Full throttle for take off, and enough throttle for 2200-2300 RPM during cruise. He doesn't really want to change his technique, even after we've explained to him the many benefits of a constant speed prop.

Obviously this isn't a very efficient way to fly, but he is (and always will be) a fair weather flyer. He never plans to make a long trip, and just likes to go up for a few hours on a nice day.

I don't like it, but is this technique harmful to the engine? I wouldn't think so. I don't know what manifold pressure he's running, but I'm guessing it's pretty low since the RPMs are at 2300 max.

What say you?
 
I don't think leaving the prop full forward is harmful unless there's an RPM limitation on it. Leaving the mixture full forward all the time is not really a good idea unless you like fouled plugs and wasting fuel.
 
The issues I see are primarily fouling related. By running at extremely low power (maybe 50% or less if he's not even reaching the governed range on the prop) with full rich mixture, the combustion temperatures may be too low to activate the lead scavenging agents in the fuel as well as very inefficient combustion. The result will be a lot of lead and carbon fouling. If he's going to do this with 100LL, you may need to pull and clean the plugs very often -- maybe every 25 hours or less. The rest of you should be prepared for fouled plugs each time he's flown the plane, and should be ready to do a lead scavenging run per Lycoming SL 185 each time you fly it after him.
 
As has been said, lead fouling will be the biggest problems. Lycomings don't list problems with ring flutter as Continentals do, but I also don't think that operating at a particularly low manifold pressure consistently (if he's doing 2300 RPM and is off the governor, I'm guessing he's <20", just a guess) is particularly good for the engine.

While I don't see him as damaging the airplane per se, I would also advocate that if he's not comfortable flying the airplane with its basic features, that he might want to consider reverting to something that's more in-line with what he is comfortable with.
 
Have him seat right seat for a few flights around the local area. Don't even mention the prop, just let him see you do it and he will probably see the benefit himself and will change on his own...nevermind the longer plug performance and fuel consumption.

I also suspect that the tach hours are running higher too. But not sure on this one.
 
Jaybird180 said:
Have him seat right seat for a few flights around the local area. Don't even mention the prop, just let him see you do it and he will probably see the benefit himself and will change on his own...nevermind the longer plug performance and fuel consumption.
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This would work assuming he's receptive to the advice. If not, it won't help at all.
 
The thing that comes to my mind, is what OTHER shortcuts might he be taking, and what else might he revert to at a later time? It's worrysome that he hasn't bothered to learn some very basic operational procedures of the airplane.
 
He may have reverted to flying it like a Warrior - but even in a Warrior you are taught how to lean. When's his next flight review? Maybe your CFI partner can have some influence on that outcome.
 
Ted DuPuis said:
This would work assuming he's receptive to the advice. If not, it won't help at all.
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Do NOT suggest it as remedial training at all. He will likely be defensive and will not learn anything. Just make it a friendly $100 hamburger run on your dime. May even better cement the friendship.
 
Jaybird180 said:
I also suspect that the tach hours are running higher too. But not sure on this one.
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For the 235, the tach is either driven by rpm (mechanical tach) or by threshold rpm (electronic tach). The tach has no input from other systems (so it doesn't know where the black, blue, or red knobs are set).
 
Is it possible for a long flight at high altitude with the mixture fully rich would cause such fouling as to effectively fail the engine?

I would definitely try to fix this somehow. If leaving the prop full forward does not harm the engine, just let him do it - but you need to get him to start leaning it properly at least. You lean a warrior...

I don't know how he passes a BFR flying around full rich all the time.. or his PPL checkride
 
Sac Arrow said:
The thing that comes to my mind, is what OTHER shortcuts might he be taking, and what else might he revert to at a later time? It's worrysome that he hasn't bothered to learn some very basic operational procedures of the airplane.
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What the Sac Arrow says.
 
I think it is reasonable to expect him to fly in accordance with the limitations and recommendations in the POH. If the POH provides a recommended leaning procedure (and altitude) then he should follow it.

For the prop RPM, I'll bet the POH makes no recommendation on what RPM to use, but does provide a table of power settings. I think full prop is acceptable unless specifically limited in the POH.
 
Sac Arrow said:
The thing that comes to my mind, is what OTHER shortcuts might he be taking, and what else might he revert to at a later time? It's worrysome that he hasn't bothered to learn some very basic operational procedures of the airplane.
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X3. This is my concern also. It is not a complex thing to learn, and to avoid something this basic would worry me about the individuals judgement, and ability to perform other decision making.
 
dell30rb said:
Is it possible for a long flight at high altitude with the mixture fully rich would cause such fouling as to effectively fail the engine?
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In theory, yes, but there would be warning signs long before total power loss.

I don't know how he passes a BFR flying around full rich all the time.. or his PPL checkride
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That's not exactly a pass/fail item.
 
Thanks guys for all the responses. When he rented the Warrior, he was told to never lean below 5000 ft, so that's why he doesn't now. The FBO where he rented it would always blame improper leaning for all engine issues in their fleet, thus the rule. He probably never goes above 3000-4000 ft on his pleasure cruises anyway.

He seems somewhat receptive to learning, but maybe from me more than my CFI partner. I think he's a little intimidated by him, so we will going up together soon. I'm having trouble explaining the constant speed propeller concepts in a way he can understand. He's not a big reader, and doesn't like theory discussions, so maybe the "show and tell" method is the way to go.

I appreciate everyone that responded to this thread. Thanks!
 
Also, I forgot to mention that fuel savings really don't enter into the discussion. He's a wealthy man.
 
Unregistered said:
Also, I forgot to mention that fuel savings really don't enter into the discussion. He's a wealthy man.
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Wealthy men don't usually like to waste money - which is what he's doing. He's also driving up maintenance costs and filling the engine full of lead.
 
Has he ever ridden a geared bicycle? Even only 3 gears? Or driven standard car? You could liken it to "shifting" into overdrive so that it's better for the plane.

I think the show and tell is best for him... From what you've said. He might not care about paying for wasted fuel but if understands that I could cause a loss of power he might care.

Good luck
 
Ron Levy said:
BTW, the answers here apply to any piston engine attached to a c/s prop, not just those over 200HP.
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Curious statement.
You must have some experience that tells you that someone might not think it obvious???
 
Unregistered said:
Also, I forgot to mention that fuel savings really don't enter into the discussion. He's a wealthy man.
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But the maintenance costs affect all of you... just tell him you would like him to do things by the book (POH) because you and your partner feel strongly that is the best way to run the airplane etc..

I would strongly suggest you make a label or something and affix it on the panel somewhere just to make things simple...

Cruise under 5,000 ft, Set Prop to xxxx rpm, xx in MP, lean .... you get the idea
 
Here's a story of how running an engine rich at high altitude for an extended period of time caused it to fail..

http://www.flyingmag.com/technique/i-learned-about-flying/i-learned-about-flying-worst-case-scenario

Long story short a twin cessna is cruising high above the mountains when an engine fails.. the failed engine is feathered and the good engine is set full throttle at full rich prop forward... runs for a while but dies (due to mixture too rich) as they are coming into an airport. It sputtered back to life as they were going to come up short and got them to the airport, then died on the taxiway.

I've heard that many engines have a baro system that leans the mixture some in the full rich position (at altitude) so that you may set the mixture at full rich at any altitude without killing the engine.. is this true?
 
Jaybird180 said:
I also suspect that the tach hours are running higher too. But not sure on this one.
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Clark1961 said:
For the 235, the tach is either driven by rpm (mechanical tach) or by threshold rpm (electronic tach). The tach has no input from other systems (so it doesn't know where the black, blue, or red knobs are set).
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He's not saying the tach is inaccurate.

He's saying that in comparing tach time to hobbs time in historical records, when this guy started flying with the prop full forward, their averages in their records are probably moving closer to being equal.

And since tach time is what's typically used for maintenance intervals...

[Edit added...]

P.S. Does he drive his car around in 1st gear everywhere? If he does, you may have a bigger problem. :) or is that :(
 
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dell30rb said:
Here's a story of how running an engine rich at high altitude for an extended period of time caused it to fail..

http://www.flyingmag.com/technique/i-learned-about-flying/i-learned-about-flying-worst-case-scenario

Long story short a twin cessna is cruising high above the mountains when an engine fails.. the failed engine is feathered and the good engine is set full throttle at full rich prop forward... runs for a while but dies (due to mixture too rich) as they are coming into an airport. It sputtered back to life as they were going to come up short and got them to the airport, then died on the taxiway.

I've heard that many engines have a baro system that leans the mixture some in the full rich position (at altitude) so that you may set the mixture at full rich at any altitude without killing the engine.. is this true?
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I don't know, but going full rich in the pattern at very high density altitudes is a common cause of engine failures. I don't richen the mixture transitioning from cruise to the pattern, especially not at a high DA airport.
 
The question is? Would I pass him on a flight review?

Answer No. They can be sloppy, and usually are. But they can't do things to kill themselves.
 
Unregistered said:
Thanks guys for all the responses. When he rented the Warrior, he was told to never lean below 5000 ft, so that's why he doesn't now. The FBO where he rented it would always blame improper leaning for all engine issues in their fleet, thus the rule. He probably never goes above 3000-4000 ft on his pleasure cruises anyway.
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More people are taught this way than you might think. My current CFII, for example, prides himself on keeping his last engine well past TBO and thinks part of it may be that he teaches all of his students to never lean unless necessary to make the engine run smoothly. He was also Maint VP until recently, and made this the recommended way to operate both of our 172s.

It's pretty much as you say: he blames all engine issues of unknown cause on improper leaning. He also claims that he's never had problems with lead fouling.
 
dell30rb said:
Here's a story of how running an engine rich at high altitude for an extended period of time caused it to fail..

http://www.flyingmag.com/technique/i-learned-about-flying/i-learned-about-flying-worst-case-scenario

Long story short a twin cessna is cruising high above the mountains when an engine fails.. the failed engine is feathered and the good engine is set full throttle at full rich prop forward... runs for a while but dies (due to mixture too rich) as they are coming into an airport. It sputtered back to life as they were going to come up short and got them to the airport, then died on the taxiway.
Click to expand...

In that case actually, I think the engine quit because he had the fuel boost pump on high and then pulled the throttle back while still at a high altitude, flooding it. While it was still running too rich at full power, it was able to burn at least enough of the fuel to keep it running. Still, he shouldn't have had the boost pump on high for that. I'd bet that if he turned off the boost pump and/or pulled back the mixture, he would've gotten it firing up again.

I've heard that many engines have a baro system that leans the mixture some in the full rich position (at altitude) so that you may set the mixture at full rich at any altitude without killing the engine.. is this true?
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Certain Continentals will do that (not the ones in the 310 I fly). As far as I know the Lycomings will not. I know that the Navajo will flood quite nicely up at altitude - last summer in Denver required a little different starting technique than I'm used to.
 
My only question is how did a CFI "check him out" and endorse his logbook for solo without being sure he was able and comfortable using the ALL the systems of the aircraft?

Pardion me for being the wet blanket in this thread but if Mr. Money has to be inticed to learn the airplane systems in a way that dosen't offend his sensibilties then maybe having him as a partner isn't the best thing...
IMPO it ain't the lead fouling, it ain't the hobbs and it ain't the fuel. It's the fact that you have a guy with an 80 knot brain in your 120 knot plane...

Chris
 
Unregistered said:
I'm writing this anonymously since I don't want to embarrass anyone. I own a Cherokee 235 with 2 other partners. One of the partners is in his mid 60's, and only has been a pilot for the last 5 years. He learned how to fly in a Warrior, and is comfortable in that plane. My other partner is also a flight instructor, and we (the flight instructor and myself) thought the 3rd partner was up to speed on the new plane. The flight instructor checked him off as good to go, but now it turns our older partner has reverted to flying the 235 like a Warrior, but in an unusual way. He is leaving the prop and mixture controls all the way forward for the entire flight, and only moves the throttle. Full throttle for take off, and enough throttle for 2200-2300 RPM during cruise. He doesn't really want to change his technique, even after we've explained to him the many benefits of a constant speed prop.

Obviously this isn't a very efficient way to fly, but he is (and always will be) a fair weather flyer. He never plans to make a long trip, and just likes to go up for a few hours on a nice day.

I don't like it, but is this technique harmful to the engine? I wouldn't think so. I don't know what manifold pressure he's running, but I'm guessing it's pretty low since the RPMs are at 2300 max.

What say you?
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It'll cost you mostly in 3 times as much spark plug servicing and an extra set of rings across the life of the engine if always run like that, plus the extra cost of fuel for him. Considering that he is only a 1/3rd user and a 'small third' at that, the damage he'll do is going to be considerably less than his share of the ownership costs, so he is still a financial benefit to the other 2 partners.
 
Hiperbiper said:
Pardon me for being the wet blanket in this thread but if Mr. Money has to be enticed to learn the airplane systems in a way that doesn't offend his sensibilities then maybe having him as a partner isn't the best thing...
IMPO it ain't the lead fouling, it ain't the hobbs and it ain't the fuel. It's the fact that you have a guy with an 80 knot brain in your 120 knot plane...

Chris
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So? Am I supposed to care if he kills himself? That's his choice, as long as I'm in a front seat, I don't much care how far behind the plane the other guy is; if I'm not in the plane, "have fun dude" what do I care? My interest will be insured.
 
azure said:
More people are taught this way than you might think. My current CFII, for example, prides himself on keeping his last engine well past TBO and thinks part of it may be that he teaches all of his students to never lean unless necessary to make the engine run smoothly. He was also Maint VP until recently, and made this the recommended way to operate both of our 172s.

It's pretty much as you say: he blames all engine issues of unknown cause on improper leaning. He also claims that he's never had problems with lead fouling.
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You have a moron for a CFII, now what are you going to do about that? What other fantasy is he teaching you?
 
dell30rb said:
I've heard that many engines have a baro system that leans the mixture some in the full rich position (at altitude) so that you may set the mixture at full rich at any altitude without killing the engine.. is this true?
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No, not 'Many', not on our small engines. The only one I'm aware of that has that available is a Continental 550. The Bings on the Rotax engines has a range of compensation as well that should get you to 10,000' or so.
 
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My Continental O-470 complains if idled full rich up here and even did at below sea level DAs in Lincoln with Jesse.

Lean it until it smooths out and the RPM will also come up a bit too.

A little further it will quit.

Right in-between is perfect.

As lean as it'll go on the ground and it will die if you move the throttle forward without a twist on the mixture knob. That's where I taxi it.

At low DA full-rich for takeoff. Up here, one and a half turns richer than peak RPM on a standard 1700 RPM run up.

Never fouled a plug yet.

Learned that lesson fouling a plug on a 172RG I used to fly. Fouled one, talked to other pilots and the owner, got my act together. Long long ago...
 
Henning said:
So? Am I supposed to care if he kills himself? That's his choice, as long as I'm in a front seat, I don't much care how far behind the plane the other guy is; if I'm not in the plane, "have fun dude" what do I care? My interest will be insured.
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Henning;
I was replying to someone who DID seem to care about the other guy in his flying club and his lack of proficency in type.
Your lack of concern was touching though...


Chris
 
Hiperbiper said:
Henning;
I was replying to someone who DID seem to care about the other guy in his flying club and his lack of proficency in type.
Your lack of concern was touching though...


Chris
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My concern about his safety is superseded by my concern for people to mind their own damn business. It's about his freedom to die, which BTW is an inalienable right just like "Life, Liberty and the Pursuit of Happiness." There is nothing anyone can say or teach or do that will prevent him (or me or anyone else) from dying. If he doesn't want to mess with the prop and mixture when I'm not in the plane, I consider it NONE OF MY BUSINESS to correct outside of presenting the educational info. He can take it or not as he pleases. It's not my place to run his life just like it's nobodies business to run mine.
 
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Henning said:
So? Am I supposed to care if he kills himself? That's his choice, as long as I'm in a front seat, I don't much care how far behind the plane the other guy is; if I'm not in the plane, "have fun dude" what do I care? My interest will be insured.
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So when the plane crashes in my kid's school yard, and takes other people with him, I'll remind you of this. Flying the plane this way is just stupid. It is bad for the aircraft, and displays poor judgment. I don't want to be in the air with this guy either. He is a danger to himself, and others in the air, and on the ground.

Your attiutude displayed in this thread isn't much better.
 
Anthony said:
So when the plane crashes in my kid's school yard, and takes other people with him, I'll remind you of this.
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And what are the odds of that happening? Your kid is probably 50x more likely to get struck by lightning
 
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