Constant Speed Prop use in traffic pattern

David Anthony

David Anthony

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David A
When it comes to flying with a constant speed propellor in a traffic pattern, do you look at rpm or manifold pressure when making power changes. Do you use both when flying in the pattern?
 
Depends on the plane. For example, the DA40 POH says to reduce from 2700RPM down to 2400RPM while still in a climb "above a safe height". The 172RG POH says 25"/2500RPM for an enroute climb. Neighbors live near the crosswind turn so I do so for their sake.
 
Rpm is an unreliable indicator with a constant speed prop, IMO. Always MAP.

I'm assuming the question wasn’t what do you change, the question was what do use use as an indicator of power setting.
 
I usually reduce to 2300 rpm on the descent. I’ll go full prop once the MP is low enough that it can’t maintain the 2300 rpm. That way it’s “off the governor” and should be making a racket for those on the ground.
 
Think about it from an oh sh** perspective; not everything is peachy one.

As your wheels touch and someone pulls onto the runway and you have to aboet and climb away. Or on base and some idiot is coming straight in on the wrong frequency... (Both of these happened to me on my current trip)

You have your hand on one lever. When you are surprised human reaction is to tense muscles not relax and spread them.
So, considering human factors; what is the best way to make the most power and not ruin the engine?

When you answer that, you know what you should be doing, where the levers should be and what gauge matters.

Tim


Sent from my HD1907 using Tapatalk
 
GUMPS starts abeam the numbers at the end of the runway.
 
David Anthony said:
When it comes to flying with a constant speed propellor in a traffic pattern, do you look at rpm or manifold pressure when making power changes. Do you use both when flying in the pattern?
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Depends on where your governor range is. Once the power drops below the governor range, the pitch goes to fine and then you fly it like a fixed pitch prop. On the 182, I use MP on downwind and RPM after the power reduction abeam the touchdown point.
 
tspear said:
Think about it from an oh sh** perspective; not everything is peachy one.

As your wheels touch and someone pulls onto the runway and you have to aboet and climb away. Or on base and some idiot is coming straight in on the wrong frequency... (Both of these happened to me on my current trip)

You have your hand on one lever. When you are surprised human reaction is to tense muscles not relax and spread them.
So, considering human factors; what is the best way to make the most power and not ruin the engine?

When you answer that, you know what you should be doing, where the levers should be and what gauge matters.

Tim


Sent from my HD1907 using Tapatalk
Click to expand...
Or if you read the manual for your engine you realize that your engine can't produce enough power to ruin it based on your rpm setting. But who reads the engine manual...
 
EdFred said:
Or if you read the manual for your engine you realize that your engine can't produce enough power to ruin it based on your rpm setting. But who reads the engine manual...
Click to expand...

Yes you can, mine strictly says not to exceed 23” below 2100 RPM
 
If you select high rpm, the airport neighbors won’t appreciate the addition noise and there is no reason to go with prop high selection until final or upon power reduction abeam the approach end of the runway. At some MP, the governor will no long hold a lower RPM and that’s a good place to go prop control forward.

You always know a rookie when you here the prop screaming on downwind.
 
There may be a clash of terminology for me, but “in the pattern” for me indicates a normal VFR landing as opposed to the steps involved in an approach. In this situation I have already done GUMPS so the prop is already firewalled. I am not watching my power instruments at this point. I’m watching airspeed, altimeter and not much else. I will be regulating power with the throttle and bringing it to the ground without watching much of anything else on the panel. My eyes are outside for the most part. Once in the pattern just watch for and communicate and fly the airplane.

Don’t get fixated on instruments in the pattern VFR. My primary instructor many years ago had trouble with me watching the instruments all the time instead of watching and flying. One day, probably 8 or 10 hours in, he put a dish towel over the panel and taught me to fly with no instruments at all.

In a jet I expect there are lots of complexities to deal with, but in GA piston plane just fly.
 
Jamie Kirk said:
GUMPS starts abeam the numbers at the end of the runway.
Click to expand...
Not in any aircraft of performance. GUMPS is the final check prior to landing, but most of those steps are likely taken before you're doing the last power reduction abeam the numbers.
 
Jamie Kirk said:
Yes you can, mine strictly says not to exceed 23” below 2100 RPM
Click to expand...
Yep, each one is different. At 2300 rpm, I can't produce enough MP to damage the engine, between 1800 (max 23") and 2300 I have to interpolate. But the plane never seems to like to go below 2200 if it isnt on the stops, so damage is never an issue.
 
MBDiagMan said:
In a jet I expect there are lots of complexities to deal with, but in GA piston plane just fly.
Click to expand...

Actually there are LESS complexities in a jet, which only has one lever, not four. Your “novel” method of flying by feel works just fine! And comes highly recommended by me at least.

Tools
 
In the bonanner, I will pull about one turn of RPM out on the climbout just to cut down on the noise for the neighbors. If I am staying in the pattern I will pull the RPM's back to 2300 once I level at pattern altitude, and leave it alone till I am on short final.
 
Clip4 said:
If you select high rpm, the airport neighbors won’t appreciate the addition noise and there is no reason to go with prop high selection until final or upon power reduction abeam the approach end of the runway. At some MP, the governor will no long hold a lower RPM and that’s a good place to go prop control forward.

You always know a rookie when you here the prop screaming on downwind.
Click to expand...
Making changes on final is not considered a stable approach. It also adds one more task in a critical phase.
Takes your eyes inside the plane, also makes you move your hand to find another lever....
None of these are conducive to avoiding mistakes, reaction time in emergency, or eyes out the window.

Tim

Sent from my HD1907 using Tapatalk
 
David Anthony said:
When it comes to flying with a constant speed propellor in a traffic pattern, do you look at rpm or manifold pressure when making power changes. Do you use both when flying in the pattern?
Click to expand...

Pretty much RPM. I’ll be at some combination of RPM and MP when entering the pattern. Initial power reduction will be done with throttle. But once power has been reduced enough that the prop ‘gets out of the governor’ then just the RPM. But not really paying that much attention to it by then. By then it’s airspeed and aiming point I’m looking at.
 
Last edited:
EdFred said:
the plane never seems to like to go below 2200
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Yea, that's about where my engine idles too. I don't have a constant speed prop, but I will usually pull back to about 5000 RPM in the pattern to keep the noise down.
 
steingar said:
The “P” in GUMPS is for prop. In the pattern it’s supposed to be all the way forward.
Click to expand...

So you can **** off airport neighbors? Awesome. Way to be an Ambassador!
 
MP until the prop governor's limit is reached then RPM.

MBDiagMan said:
In a jet I expect there are lots of complexities to deal with, but in GA piston plane just fly.
Click to expand...
Not really. The main "complexity" is speed and the management of speed. Slowing down to the max flap speeds can be a challenge is you are too high and/or fast. Requires planning well before reaching the pattern. Faster speeds make it much more difficult to see and follow slower traffic at non-towered fields.

The aircraft systems are simpler to operate than those in the Mooney in your Avatar. The engines are simple. Push to go faster, pull to go slower, spool by 1000'. On some jets you turn on the ignitors for landing, some you don't. Flaps, put them down on schedule. Gear, down is good. Spoilers, arm. In most jets, you have another pilot who does most of that for you.
 
flyingron said:
Not in any aircraft of performance. GUMPS is the final check prior to landing, but most of those steps are likely taken before you're doing the last power reduction abeam the numbers.
Click to expand...

You start GUMPS on final, must suck to have to fly so rushed. On final I’m 100% configured ready to land and stabilized.
 
Jamie Kirk said:
You start GUMPS on final, must suck to have to fly so rushed. On final I’m 100% configured ready to land and stabilized.
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I'm not understanding you. I'm not rushed and I won't be stabilized if I make major configuration changes on final. The gear is down way before abeam the numbers (when in a VFR pattern and IFR it usually comes down at the FAF) and in my plane I tend to leave the gear up longer than in most retracts (since the Vle is fairly low).
 
Larry in TN said:
MP until the prop governor's limit is reached then RPM.


Not really. The main "complexity" is speed and the management of speed. Slowing down to the max flap speeds can be a challenge is you are too high and/or fast. Requires planning well before reaching the pattern. Faster speeds make it much more difficult to see and follow slower traffic at non-towered fields.

The aircraft systems are simpler to operate than those in the Mooney in your Avatar. The engines are simple. Push to go faster, pull to go slower, spool by 1000'. On some jets you turn on the ignitors for landing, some you don't. Flaps, put them down on schedule. Gear, down is good. Spoilers, arm. In most jets, you have another pilot who does most of that for you.
Click to expand...

So it’s true. You can teach a monkey to fly a jet. :rofl: keep scrolling down to get the text in the left column.
https://www.express.co.uk/travel/articles/1067252/flights-pilot-cabin-crew-flight-attendant-prank
 
Jamie Kirk said:
You start GUMPS on final, must suck to have to fly so rushed. On final I’m 100% configured ready to land and stabilized.
Click to expand...

Never flown a 15+ mile final or did you drag it alllllll the way in? ;)
 
tspear said:
Making changes on final is not considered a stable approach. It also adds one more task in a critical phase.
Takes your eyes inside the plane, also makes you move your hand to find another lever....
None of these are conducive to avoiding mistakes, reaction time in emergency, or eyes out the window.

Tim

Sent from my HD1907 using Tapatalk
Click to expand...

Let me see if I understand this, changing a flap setting on final is stabilized, but pushing in a knob isn’t?
 
Flying a C-185 with the prop full forward will not make you any friends on the ground. If you are doing pattern work, there is no need for max rated takeoff power and reducing prop RPM for METO of much less is good practice.

GUMPS is done on downwind, base and final and repeated as often as necessary to arrive at the runway, ready to go around.

The OP was asking about prop use in the pattern and the answer is to manage power by adjusting MP and RPM to transition from climb, level and descent as needed.
 
Clip4 said:
Let me see if I understand this, changing a flap setting on final is stabilized, but pushing in a knob isn’t?
Click to expand...
Never said that.

Tim

Sent from my HD1907 using Tapatalk
 
I guess I’m still a 16 year old and immature at heart. I like loud things. I put prop full forward when I feel like it’s called for in my plane and style of flying and it’s usually at pattern entry or before during VFR flight, and much earlier in the approach IFR. Maybe that’s inconsiderate and bad for the sport. I probably should care, but I don’t.
 
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