Props High or Low?

[wt219200]

If you lost an engine in a complex single like the Piper Arrow or even just training sim-engine out would you pull props to low RPM or keep them high? Situation: 3000 AGL. I would go high but a nameless fellow CFI I will call B L argues keep em high. Debate on

I also meant to state the engine restart was unsuccessful lets say fuel starvation. In this case the CFI still argues props high

 

[USMCmech]

High RPM gives you the best chance for a restart.

Low RPM gives you the best glide distance.


Use the aproprite setting for your situation.


For training purposes, you are going to do a go-around sometime soon, so I have my students leave them high.

 

[heph224]

If your engine fails, put the blade at a high RPM and try to restart. Then, if the restart was unsuccesful, set the lever to a low rpm pitch setting to decrease drag and get a better glide distance.

 

[minitour]

I agree with going high pitch/low RPM to get your best glide after you were at low pitch/high RPM to attempt a re-start.

HOWEVER...the complex singles I've flown all use oil pressure to drive the prop into a high pitch/low RPM condition...so if you lose the engine, you MAY not be able to get the prop into that low RPM/high pitch condition.

..just something to think about.

-mini

 

[Sam Snead]

Complex single; I teach; once you've decided not to continue trying to restart;

Leave it high RPM unless you can't make your field. Then pull the prop all the way back.

In a poorly planned or unlucky situation, the "boost" you get from the quasi-feather might just get you up and over the last row of trees.

If you've got the field made, leave the prop where it was.

But, (as minitour pointed out) if you have nil oil pressure, you may not be able to go to low RPM. So hope you have an engine failure without massive oil starvation.

 

[aucfi]

For traning purposes, I would not touch the prop control; just leave it full forward. I do show my studends how much drag the prop creates when in the high rpm setting by pulling it back to the low rpm setting one time.

If it actually occured, Id follow the POH's instructions. The checklist does not call for a change in prop setting following a failed attempt to restore power but the amplified procedures suggest moving it to the full decrease rpm to prolong gliding distance.

"At best gliding angle, with the engine windmilling, and the propeller control in the full 'DECREASE rpm," the aircraft will travel approximately 1.6 miles for each thousand feet of altitude."

Thats from an Arrow 3 POH

 

[troy]

It depends on the terrain below you, here in South Dakota, landing spots are plenty, but in the mountains, pull it back.

 

[Iceman21]

Mini is right, if you have lost oil pressure then the prop (in most piston singles) will revert to HIGH rpm and you are stuck with it there.


Now if you ran out of gas, on the base leg, now were talking.

 

[Dr Pokenhiemer]

Pull the props back and increase your glide. So you think you can make the field? What happens if you run into stronger winds as you get lower and all of sudden you realize you can't make it? You'll wish you would've pulled it back from the getgo.

For training purposes? Train like the real thing. Don't be afraid to show your students how the plane will perform. That's your job!! Train them to handle emergencies!! You are there so they WON'T get out of control. You are there to make sure the prop goes full forward before the go around. Do a simulated engine out on downwind. Teach them to deadstick the landing--they'll have to do it on the checkride.

 

[aucfi]

Pull the props back and increase your glide. So you think you can make the field? What happens if you run into stronger winds as you get lower and all of sudden you realize you can't make it? You'll wish you would've pulled it back from the getgo.

For training purposes? Train like the real thing. Don't be afraid to show your students how the plane will perform. That's your job!! Train them to handle emergencies!! You are there so they WON'T get out of control. You are there to make sure the prop goes full forward before the go around. Do a simulated engine out on downwind. Teach them to deadstick the landing--they'll have to do it on the checkride.

So do all instructors tell their students to pull their prop back during every simulated engine out? I was never taught to do this but was made aware that I could if needed. Would that cause excess wear on the speeder spring? Just curious...

If you train without pulling it back and consistently make the field/runway without any problem, it shouldnt matter whether you pull it back or not if you had an actual failure. Common sense and good judgement (through training) should tell you whether you should have to pull it back if you really needed the extra distance.

Going back to my previous post; the actual checklist does not say pull it back if a restart cannot be made. The amplified procedures simply points out how far you can glide with the prop in the full decrease position. Seems to me Piper left it up to the PIC to make that decision.

 

[check6]

I would go high but a nameless fellow CFI I will call B L argues keep em high.

I fail to see the disagreement here.

 

[NoPax]

Prop handle position doesn't affect the engine when attempting a restart...

Pull the handle back, and get as much glide out of it as possible. The engine failed for a reason - no fuel, oil starvation/seizure.

In the Aero Commander 500, you have to put the prop handle just out of feather ie in low rpm setting to restart the engine (2000RPM). If you put it to high rpm it causes too much stress on the engine, and warms it up too quickly.

 

[taloft]

Of all the things to worry about during engine failure in a light single...

I was always happy if a student just trimmed for best glide and successfully setup for landing.

I can see it now...

(as airplane descends toward the ground)
CFI: "Did you set high RPM pitch?"
Student: "Is that prop in or out"
CFI: "In"
Student: "Ok it's in, but my other instructor said not to do that until doing a go around"
CFI: "Really?"
Student: "Well yeah, he said something about always training me to push prop in first, then throttle. But that was at Riddle."
CFI: "Oh I suppose that makes sense. Well just do it this way for now."
Student: "Ok"
CFI: "Hey, did you do engine restart procedure yet?"
Student: "Oh I forgot. Sorry you distracted me. Um, where should the prop be for restart."
CFI: "In"
Student: "Ok, so that's high RPM, right?"
CFI: "yeah like I just showed you"
Student: "Oh, I see why you wanted high RPM earlier. Hey, wouldn't we get better glide with low RPM?"
CFI: "yeah, there'd be less drag. Hey, you never set best glide speed. Why didn't you do that?"
Student: "I'm still adjusting this prop control knob."
CFI: "I see.. where are we going to land?"
Student: "Land? I thought we were going to do a restart?"
CFI: "Well you better get best glide."
Student: "Ok I'm finally at best glide. whew. Should I pull out the prop knob now."
CFI: "Sure, go ahead. No, wait, leave it in."
Student: "What?"
CFI: "We're going to have to go around now. See those trees? Go around!"
Student: "Ok.. So was that prop in or out now?"

 

[wt219200]

props low

I fail to see the disagreement here.

meant to say I would go props low RPM I think everyone has figured this out by now

 

[wt219200]

Funny

Of all the things to worry about during engine failure in a light single...

I was always happy if a student just trimmed for best glide and successfully setup for landing.

I can see it now...

(as airplane descends toward the ground)
CFI: "Did you set high RPM pitch?"
Student: "Is that prop in or out"
CFI: "In"
Student: "Ok it's in, but my other instructor said not to do that until doing a go around"
CFI: "Really?"
Student: "Well yeah, he said something about always training me to push prop in first, then throttle. But that was at Riddle."
CFI: "Oh I suppose that makes sense. Well just do it this way for now."
Student: "Ok"
CFI: "Hey, did you do engine restart procedure yet?"
Student: "Oh I forgot. Sorry you distracted me. Um, where should the prop be for restart."
CFI: "In"
Student: "Ok, so that's high RPM, right?"
CFI: "yeah like I just showed you"
Student: "Oh, I see why you wanted high RPM earlier. Hey, wouldn't we get better glide with low RPM?"
CFI: "yeah, there'd be less drag. Hey, you never set best glide speed. Why didn't you do that?"
Student: "I'm still adjusting this prop control knob."
CFI: "I see.. where are we going to land?"
Student: "Land? I thought we were going to do a restart?"
CFI: "Well you better get best glide."
Student: "Ok I'm finally at best glide. whew. Should I pull out the prop knob now."
CFI: "Sure, go ahead. No, wait, leave it in."
Student: "What?"
CFI: "We're going to have to go around now. See those trees? Go around!"
Student: "Ok.. So was that prop in or out now?"

Funny situation I see your point but couldn't it be explained just a little simpler
throttle out props out
props in throttle in

 

[nosehair]

Of all the things to worry about during engine failure in a light single...

I was always happy if a student just trimmed for best glide and successfully setup for landing.

I can see it now...

(as airplane descends toward the ground)
CFI: "Did you set high RPM pitch?"
Student: "Is that prop in or out"
CFI: "In"
Student: "Ok it's in, but my other instructor said not to do that until doing a go around"
CFI: "Really?"
Student: "Well yeah, he said something about always training me to push prop in first, then throttle. But that was at Riddle."
CFI: "Oh I suppose that makes sense. Well just do it this way for now."
Student: "Ok"
CFI: "Hey, did you do engine restart procedure yet?"
Student: "Oh I forgot. Sorry you distracted me. Um, where should the prop be for restart."
CFI: "In"
Student: "Ok, so that's high RPM, right?"
CFI: "yeah like I just showed you"
Student: "Oh, I see why you wanted high RPM earlier. Hey, wouldn't we get better glide with low RPM?"
CFI: "yeah, there'd be less drag. Hey, you never set best glide speed. Why didn't you do that?"
Student: "I'm still adjusting this prop control knob."
CFI: "I see.. where are we going to land?"
Student: "Land? I thought we were going to do a restart?"
CFI: "Well you better get best glide."
Student: "Ok I'm finally at best glide. whew. Should I pull out the prop knob now."
CFI: "Sure, go ahead. No, wait, leave it in."
Student: "What?"
CFI: "We're going to have to go around now. See those trees? Go around!"
Student: "Ok.. So was that prop in or out now?"

........!CLASSIC!!....Excellent justification for NOT teaching the best, most efficient, taking-all-things-into-consideration, way of handling/controlling the airplane.
"Just keep it simple." "You'll confuse the student." "Why make a mountain out of a molehill."...and on and on, yada,yada,yada.
Yes! All those things apply to the BEGINNING STUDENT PILOT. The scene you describe in your scenario would be happening if you try to cram the whole thing down his throat at first, but once he has basic glide control and making the field judgement, then you add the other stuff, as he is able to do it. In the end, no student pilot should ever get certified to carry pax without full and complete control of all of the equipment that he has at his command.

....but that isn't what's happening, is it? it has become the standard to just "get by", pass the test. they don't make you "pull the prop back" on the test, do they?...so why bother....

 

[Gorilla]

When practicing engine-out work in light singles, nothing prepared me better than having significant glider time - setting up the glide, total energy, path control, overall glide ratio, and field selection - all come naturally to glider types. I know it's not always an option due to cost, but if I was a new PP, I'd chase a glider rating before a multi or instrument rating. It'll make you a better pilot.

I understand the issues here, and I think some excellent advice has been made, but my thought, and I'm not a CFI but was a CFIG, would be to set EVERYTHING up for a flameout landing, including prop, before screwing with restart. That may be nothing more than setting up the glide, identifying landable terrain, pointing towards it, breathing that mental "I've got it made" sigh of relief, and then pursuing a restart.

 

[Dr Pokenhiemer]

Let me ask a question. Do you always practice power out in the pattern? They always make the field? Engines don't always fail in the pattern. Take your student to 4500msl. Have them start a steep turn and pull the trottle. Inform them they've just lost the engine. Have them go through the emergency start sequence. Now the engine is running again--but now it's on fire!! Engine fire checklist. Now find a place to land. As you get lower, give a little throttle to clear the carb. so it doesn't sputter on you when you do the go around. If you have constant speed prop--it should be pulled back asap to give more gliding distance. I used to do this to my students and it really boosted their confidence and made me feel very good about them being able to handle emergencies. I even do this to pilots during flight reviews. They thank me for reminding them about the things they don't go out and practice on their own.

 

[aucfi]

Do you always practice power out in the pattern?

Of course not. My previous posts were not intended to be "just in the pattern" scenarios.

I appreciate the input Dr. but you know how primacy is. Is it right or wrong to leave the prop high rpm? Whos to say? Afterall that was the intent of the topic starter, to find out opinions.