Constant speed prop transition to cruise

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mxalix258

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mxalix258
Quick question for those that fly with a constant speed propeller, is the only time appropriate to use "full power" during take-off and go-around?

Say for example I take off and level off at 2,000 ft momentarily and setup at a cruise setting...if you wanted to continue your climb to say, 8,000 would you use a cruise climb setting or put everything back in for a full power climb? Is either wrong to do?
 
mxalix258 said:
Quick question for those that fly with a constant speed propeller, is the only time appropriate to use "full power" during take-off and go-around?

Say for example I take off and level off at 2,000 ft momentarily and setup at a cruise setting...if you wanted to continue your climb to say, 8,000 would you use a cruise climb setting or put everything back in for a full power climb? Is either wrong to do?
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Prop full forward for takeoff, climb and final. When transitioning to cruise, bring it back to your calculated cruise rpm for your desired performance. If you're doing step climbs, I normally bring it back to an intermediate setting (in my 182, 2500) for brief level offs when climbing out under shelves. I can still cruise climb at 2500 and not have to mess with the prop again until final cruise altitude.
 
mxalix258 said:
Quick question for those that fly with a constant speed propeller, is the only time appropriate to use "full power" during take-off and go-around?

Say for example I take off and level off at 2,000 ft momentarily and setup at a cruise setting...if you wanted to continue your climb to say, 8,000 would you use a cruise climb setting or put everything back in for a full power climb? Is either wrong to do?
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Neither is wrong or harmful unless your plane is placarded with time limits for full power or rpm settings. If those limits exist, please fly in accordance with the engine or airframe manufacturer's directions.

Why would you chose a full power climb versus cruise climb? To get over weather/obstructions. Why would you cruise climb? Lower deck angle is easier on the passengers and provides you with a better view for traffic spotting. Also better engine cooling (higher airflow) particularly in summer conditions.

-Skip
 
mxalix258 said:
Quick question for those that fly with a constant speed propeller, is the only time appropriate to use "full power" during take-off and go-around?

Say for example I take off and level off at 2,000 ft momentarily and setup at a cruise setting...if you wanted to continue your climb to say, 8,000 would you use a cruise climb setting or put everything back in for a full power climb? Is either wrong to do?
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Use full throttle whenever you want. There are no 'rules' for going fast or climbing quicker.
 
mxalix258 said:
Quick question for those that fly with a constant speed propeller, is the only time appropriate to use "full power" during take-off and go-around?
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No, but exactly what power setting to use for climb varies between aircraft, so consult your POH for that. Also, you may find that above 10,000 feet or so, you need "full power" (throttle and prop both full forward) to achieve normal cruise power (or as close as you can get).

Say for example I take off and level off at 2,000 ft momentarily and setup at a cruise setting...if you wanted to continue your climb to say, 8,000 would you use a cruise climb setting or put everything back in for a full power climb? Is either wrong to do?
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That would depend on the power the POH calls for in climb. Read your POH and do what it says unless you have a real good reason to do otherwise.
 
Brad Z said:
Prop full forward for takeoff, climb and final.
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When it comes to climb, that may be, or it may not be. Read your POH.
When transitioning to cruise, bring it back to your calculated cruise rpm for your desired performance.
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Don't do that until you've accelerated to cruise speed and brought the throttle back to cruise MP. You want to be in the habit of pulling the throttle first for power reductions, but pushing the prop first for power increases.
 
CTLSi said:
Use full throttle whenever you want.
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This isn't good advice without qualification. There are quite a few aircraft with important limitations on use of maximum power. Make sure you know your airplane's limitations, and observe them.
 
mxalix258 said:
Quick question for those that fly with a constant speed propeller, is the only time appropriate to use "full power" during take-off and go-around?

Say for example I take off and level off at 2,000 ft momentarily and setup at a cruise setting...if you wanted to continue your climb to say, 8,000 would you use a cruise climb setting or put everything back in for a full power climb? Is either wrong to do?
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Depends on the engine, most that are .5hp/CuIn will be continuous duty, most higher performance engines will have a full "Take Off" power limit around 5 minutes.
 
It all depends.

Some constant speed props you might never even touch. Like in the O-470-U engines in the Cessna 180/182. Their max RPM is 2400, and many stay that way from takeoff to landing.
 
I've that engine in our 182Q, I leave the prop full forward until I get to my final cruise altitude. If I am leveling off, I usually pull the throttle back, but leave the prop forward. :D I tend to cruise at 2300 RPM. ;)
kgruber said:
It all depends.

Some constant speed props you might never even touch. Like in the O-470-U engines in the Cessna 180/182. Their max RPM is 2400, and many stay that way from takeoff to landing.
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Between planning an upcoming flight, the 25/25 thread and the climb rate thread, I've been thinking about this topic lately. As Ron said, check the POH. In my case, the POH referred elsewhere, and the real answers were in the Lycoming operators manual, tech tips, and key reprints.
 
Henning said:
Depends on the engine, most that are .5hp/CuIn will be continuous duty, most higher performance engines will have a full "Take Off" power limit around 5 minutes.
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I agree with "depends on the engine" but disagree with "most higher performance engines... 5 Minutes". IME more often than not a time restriction on max RPM is due to a prop issue although in some cases it's the combination of a prop and a crankshaft plus counterbalances (dampers). And depending on what you mean by "higher performance" these limitations are more the exception than the rule, at least for HO direct drive engines.
 
Theboys said:
I normally set prop and mp to cruise and do a cruise climb. Keeps head temp and turbine temps down. Still climbs fast enough.
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The engines in my Baron are rated for continuous operation at max RPM (2625) and MAP. I generally climb at max RPM but my prop tips are only running about .85-.89 mach at max RPM and climb airspeed. I do climb at a fairly high airspeed which keeps things nice and cool.
 
When in doubt, consult the POH.
The folks who built your plane have your answer.

For your example, I would use a cruise climb in my plane.
However, the POH allows higher power climb settings, all the way to full if needed for clearing terrain, etc.
 
Sac Arrow said:
Please tell me you aren't serious.
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I would note that it seems CTLSi is an ink-wet PP-Airplane whose experience is limited to a Rotax-powerd S-LSA. Please consider that when reading his posts -- I think he just doesn't know any better, and unfortunately doesn't realize that there is more in aviation than is dreamt of in his philosophy, Horatio. Perhaps if he reads the responses to his ill-conceived posts he may learn -- only time will tell.
 
Maybe our friend should preface his advice with "my plane has/does. . . "

For example, I always climb WOT & max RPM. For intermediate level offs, I always set appropriate power for the altitude; i.e., reduce throttle then RPM to a reasonable setting for the altitude and lean, then for the next climb go Full Rich, Max RPM and WOT in that order. Usually, though, I am cleared to the next altitude before reaching the first, or as I am starting to level off. Intermediate leveling is much more common on descent.

It's nice flying a plane without time limits on either power or RPM. :yes:
 
What does the POH say? In the Arrow I'll keep in cruise climb power from about 500ft AGL all the way to my cruising altitude, then level off, let speed build up and pull back the throttle and prop.
 
As a guy, when all else fails, read the instructions! (POH) :D Lots of different engine and airframe combinations out there and a lot of them are operated differently. ;)
 
mxalix258 said:
Quick question for those that fly with a constant speed propeller, is the only time appropriate to use "full power" during take-off and go-around?



Say for example I take off and level off at 2,000 ft momentarily and setup at a cruise setting...if you wanted to continue your climb to say, 8,000 would you use a cruise climb setting or put everything back in for a full power climb? Is either wrong to do?
Click to expand...


Depends on the aircraft. Have to read the POH. My particular POH has everything full forward for a "max performance climb" right in the checklist and there's no time or other restrictions on using it. Other aircraft have different limitations.

My rule of thumb is if I can't get 500 feet per minute, I shove it all forward. Around here, I can't make 100% power anyway.

I can only do that in my turbo diesel pickup truck. And apparently it can't even do it with a blown head gasket on #1. ;)
 
If for no other factor than noise, the answer really is yes, especially with fuel prices being what they are. Using high power to climb makes sense because excess HP transitions in a linear fashion to rate of climb. However once leveled out, excess HP turns into speed at the inverse square. For every doubling of speed you square the power. So it makes good economic sense to power back.

You can power back three ways, MP, RPM, Fuel Flow, or any combination of the three. I start with fuel flow, because excess fuel costs me the most money both at the pump and in maintenance. I also reduce RPM to whatever the engine seems to be smoothest at without taking me below my target airspeed.
 
N747JB said:
I've that engine in our 182Q, I leave the prop full forward until I get to my final cruise altitude. If I am leveling off, I usually pull the throttle back, but leave the prop forward. :D I tend to cruise at 2300 RPM. ;)
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You should just install a fixed pitch prop and save some money.:D
 
Ron Levy said:
You want to be in the habit of pulling the throttle first for power reductions, but pushing the prop first for power increases.
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I still don't get the logic behind this. I may do it by instinct (Don't fly much CS - BradZ can you chime in here - I don't recall us doing many power changes in your Skylane).

But no CFI has ever complained about my operating habits and I haven't broken an engine yet...breaking the C-182N on runup wasn't my fault....really:D
 
Jaybird180 said:
I still don't get the logic behind this. I may do it by instinct (Don't fly much CS - BradZ can you chime in here - I don't recall us doing many power changes in your Skylane).

But no CFI has ever complained about my operating habits and I haven't broken an engine yet...breaking the C-182N on runup wasn't my fault....really:D
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There are operating rules still left over from WWII operating heavily supecharged (stacked in series mechanical with a turbo some of them) where if you pull back on the prop first from a high power situation, you'll run into an overboost. The legends and procedures often outlive the technology.
 
farmerbrake said:
Excuse my inexperience, but is this possible to do? What benefit/ drawback is there?
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The drawback on a utility airplane like a Cessna 180, especially on floats, would be a reduced thrust at low speed. It would make it more difficult to get on the step, which is already the most limiting factor in most floatplane takeoffs.
 
farmerbrake said:
Excuse my inexperience, but is this possible to do? What benefit/ drawback is there?
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Difficult and not worthwhile. The drawback is that the engine will either to make RPM, or you have to reduce throttle to exceed redlining, at the end of the envelope it's not optimized for, or you get less speed and less climb if you've pitched between a 'climb' and 'cruise' prop.
 
Henning said:
There are operating rules still left over from WWII operating heavily supecharged (stacked in series mechanical with a turbo some of them) where if you pull back on the prop first from a high power situation, you'll run into an overboost. The legends and procedures often outlive the technology.
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Long live the King AFH
 
farmerbrake said:
Excuse my inexperience, but is this possible to do? What benefit/ drawback is there?
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I don't know if it's possible regulatory wise. It would likely be experimental, get a one time sign off, or go for an STC. The only advantages would be lower weight and lower cost of ownership. The draw back is lower overall performance.

It was a joke. The guy said he never touched the prop control, so max RPM for the whole flight. So it would seem like, why have a constant speed prop then? However, he did say that he reduces the throttle during cruise, so in fact the prop is moving. As the engine produces less HP, the prop automatically changes pitch to maintain that max 2400 RPM. So he is using the prop, just not the prop control knob.

Again, it was a joke.;)
 
I figured it was a joke, just had to ask incase there was a chance it wasn't. Have to learn somehow right?
Sorry for the minor thread hijack OP!
 
Jaybird180 said:
I still don't get the logic behind this. I may do it by instinct (Don't fly much CS - BradZ can you chime in here - I don't recall us doing many power changes in your Skylane).

But no CFI has ever complained about my operating habits and I haven't broken an engine yet...breaking the C-182N on runup wasn't my fault....really:D
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Regarding Cap'n Ron's point about reducing throttle before prop, that's true, provided there's a need. Generally at anything above 6,000 I'm going to be wide open throttle (WOT) to get the power setting I need. So, once reaching cruise, I generally just need to bring the prop back to somewhere between 2,200 and 2,450 RPM.

Also, bringing the prop back will cause the MP to rise a few tenths, so if you do need to pull the throttle back first, aim for 22.7 inches of your going for 23 inches of MP since slowing the prop will cause a rise of mp.

Jaybird180- last time we flew, we were mostly in the pattern so not much playing with the prop. I just pulled it back and leaned it during the short cruise period. Generally, I'm of the belief the fewer changes the better.

(Btw-we need to get up and fly again...)
 
Dav8or said:
I don't know if it's possible regulatory wise. It would likely be experimental, get a one time sign off, or go for an STC. The only advantages would be lower weight and lower cost of ownership. The draw back is lower overall performance.

It was a joke. The guy said he never touched the prop control, so max RPM for the whole flight. So it would seem like, why have a constant speed prop then? However, he did say that he reduces the throttle during cruise, so in fact the prop is moving. As the engine produces less HP, the prop automatically changes pitch to maintain that max 2400 RPM. So he is using the prop, just not the prop control knob.

Again, it was a joke.;)
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The Pireps at MAPA, the Mooney test pilot says the way Mooneys are meant to be flown is prop full forward takeoff to landing, also throttle full takeoff to descent, leaned during cruise.
 
Brad Z said:
Jaybird180- last time we flew, we were mostly in the pattern so not much playing with the prop. I just pulled it back and leaned it during the short cruise period. Generally, I'm of the belief the fewer changes the better.

(Btw-we need to get up and fly again...)
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Get no argument from me.
 
Jaybird180 said:
The Pireps at MAPA, the Mooney test pilot says the way Mooneys are meant to be flown is prop full forward takeoff to landing, also throttle full takeoff to descent, leaned during cruise.
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Oh, people say lots of stuff and have all kinds of theories. You can fly your Mooney that way if you want and it'll be fine, but in my experience it just makes a lot of noise and uses extra fuel for little to no gain. I suspect that if the plane was "meant" to be flown that way, there might be that suggestion in the POH.;)

I rarely fly over 7500 ft these days, so maybe there is an advantage flying balls to the wall up higher in the O2 world, I don't know. I do know that at the levels I fly that with WOT, a reduction in RPM from 2500 to 2400 not only reduces vibration and fuel flow, but I actually pick up about 1kt. I shoot for WOT, ram air on, 2400 RPM and leaned to 8.5 - 9 gph.
 
Jaybird180 said:
I still don't get the logic behind this. I may do it by instinct (Don't fly much CS - BradZ can you chime in here - I don't recall us doing many power changes in your Skylane).

But no CFI has ever complained about my operating habits and I haven't broken an engine yet...breaking the C-182N on runup wasn't my fault....really:D
Click to expand...

What do you do in your car when you want to slow down? Back off the gas, then downshift. What about when you want to go faster? Kick it in a lower gear, then push on the gas pedal. Prop control = transmission.
 
In the Arrow by the way, I normally do a cruise climb if it's just 1 or 2 thousand feet in the OP's scenario, otherwise I go back to a climbout power configuration, particularly if terrain is involved.
 
I don't do a lot of knob pushing/pulling.

Takeoff: Full forward on both. Reduce in climb as required by POH- prop then throttle.....wait is the other way round....(does it really matter????)
Cruise: Reduce RPM if required, after speed stabilizes, reduce throttle if required (usually not depending upon altitude)
Descent: reduce throttle until at bottom of green arc. RPM begins to go forward
Pattern & Again Short Final, during GUMPS: Full forward on Blue knob
 
Jaybird180 said:
I don't do a lot of knob pushing/pulling.

Takeoff: Full forward on both. Reduce in climb as required by POH- prop then throttle.....wait is the other way round....(does it really matter????)
Cruise: Reduce RPM if required, after speed stabilizes, reduce throttle if required (usually not depending upon altitude)
Descent: reduce throttle until at bottom of green arc. RPM begins to go forward
Pattern & Again Short Final, during GUMPS: Full forward on Blue knob
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Generally reversed (yes it matters). Reduce power, adjust Throttle Prop Mixture in that order, add power, adjust Mixture Throttle Prop in the opposite order. That's why the knobs are arranged in that particular order, so you can go left to right and right to left.
 
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