Another 182 Question

[BrianR]

On climbout, the CFI was on me rather adamantly to get the power back to 23 in. MP and the prop back to 2400 rpm no later than 400-500 ft agl.

But in my simple mind, I know that statistically, an engine failure on takeoff is most likely to occur at the first power reduction. Therefore, wouldn't it make more sense to leave the power alone until reaching an altitude of, say, 700-1000 ft, where, in the event of engine failure, the "impossible turn" would more than likely be possible?

What's the rush to reduce the power? Risk of overheating? Overspeed? The POH is rather vague on the topic, just mentioning power/prop reduction in cruise climb. And the Airplane Flying Handbook doesn't address this issue either.

This is my first experience with a constant speed prop (as well as an engine with more than 180 hp). In the flying I've done behind smaller engines and fixed pitch props, I was always taught to just leave it at full power until reaching cruise altitude.

 

[gismo]

On climbout, the CFI was on me rather adamantly to get the power back to 23 in. MP and the prop back to 2400 rpm no later than 400-500 ft agl.

But in my simple mind, I know that statistically, an engine failure on takeoff is most likely to occur at the first power reduction. Therefore, wouldn't it make more sense to leave the power alone until reaching an altitude of, say, 700-1000 ft, where, in the event of engine failure, the "impossible turn" would more than likely be possible?

What's the rush to reduce the power? Risk of overheating? Overspeed? The POH is rather vague on the topic, just mentioning power/prop reduction in cruise climb. And the Airplane Flying Handbook doesn't address this issue either.

This is my first experience with a constant speed prop (as well as an engine with more than 180 hp). In the flying I've done behind smaller engines and fixed pitch props, I was always taught to just leave it at full power until reaching cruise altitude.

First of all that statistic about power failures and first reduction is pure OWT with absolutely no data to back it up and there's no logical reason for such a correlation. Second, unless your engine has a METO limit (e.g. Full RPM & MP limited to 5 minutes) the only reason to reduce anything is noise reduction and decreasing RPM 100 or so will normally take care of that (leave the throttle wide open so you don't lean the mixture by closing the power enrichment mechanism if there is one).

So check your POH for a METO setting and/or full power time limit and if there isn't on (it will be in the LIMITATIONS section) ask the CFI what his basis is for reducing power which is contrary to safety (full power gets you to a safe altitude sooner).

 

[denverpilot]

You're flying a Q model so you might have an O470U, the higher compression version of the O470 and the only oddball of the older fleet. Check the POH. If you have an O470S...

That's the same engine as my bird. No limitation on Wide Open Throttle (WOT you'll see around here often and on other online forums) at 2600 RPM. It's even called for in the Maximum Performance Climb checklist.

So the instructor is a bit jumpy if he's demanding an immediate reduction to the green arc. Nothing wrong with doing it right away as part of the climb checklist, but it's not required.

You pointed out one reason to do so below 7000'. Cooling. Watch the CHT gauge and be nice to it. Slow long climbs will kill cylinders in the 182. Especially if the engine baffles are neglected.

That and the inappropriately high deck angle, even at Vy at low altitudes. You can't see traffic over the nose when you're going up at 2000'/min, lightly loaded so put the nose down and speed up for both. At Vx it's worse.

No need to go bombing around the pattern at over 100 knots so...

It's prudent to pull it back as soon as you're comfortable when doing pattern work. In XC flights, just leave it up, climb fast to keep it cool, and MP will drop on its own as you gain altitude. Lean as appropriate on the way up, too but don't get wild. Keep it rich enough to help with cooling.

Now cruise. That's a different story. The limitation in cruise called out in the POH is 75% power continuous or less. So you can climb it as fast as temperatures will allow but if you're not leveling above 7000' you'll see the MP is still above 23" (and you're above 75% power) and you need to pull it back. Above 7000' you won't make 23".

(Keep in mind that's 7000' Density Altitude not MSL. If its cold out you'll have to go higher or pull some power off at cruise. Read the tables in the POH for power settings.)

Another thought. You're off the fuel flow charts above 75% power and full rich at lower altitudes, and she'll suck down gas like there's no tomorrow. 230 HP continuously eats a lot of fuel.

Be kind to it. Get used to getting the power and RPM pulled back after takeoff unless you need the performance. Up here on a hot day, fully loaded, I do need it. At lower altitudes just ease her back a bit. It happens quick because lightly loaded you're at or above pattern altitude in less than 60 seconds if the VSI says 1000 FPM or greater.

Check your specific engine and POH limitations. The U has some different RPM limits if I remember correctly, and may have other limits.

 

[Skylane81E]

WOT and full RPM all the way up

 

[Skylane81E]

Check your specific engine and POH limitations. The U has some different RPM limits if I remember correctly, and may have other limits.

The U has a 2400 RPM redline so fair to guess that isn't what the OP is flying behind.

I always want the performance because in airplanes speed is life and altitude is life insurance. I want that altitude in the bank.

 

[BrianR]

Well...had another 2.0 hours today in the 182Q, and I pushed the CFI about the power reduction thing. He acknowledged it was strictly a PIC decision and not an overheating issue. He thinks it's better for the engine to get it back sooner, but did note that there's no real reason it has to be done at 500 feet.

And I must say, after doing about 5000 landings today, in every conceivable configuration, (1) I had absolutely no issues with flaps 40 as long as I maintained adequate speed, and (2) there's a tremendous difference between 60 and 65 kts on short final. At 60, it just drops like a rock, while at 65-70, it was a nice landing every time. And (3) the thing has such a high deck angle on takeoff, an engine failure shortly after becoming airborne leaves you about 0.5 seconds to get the nose down before you stall it and kill yourself.

 

[nosehair]

the thing has such a high deck angle on takeoff, an engine failure shortly after becoming airborne leaves you about 0.5 seconds to get the nose down before you stall it and kill yourself.

That's empty, right? Just you and the instructor. Wait til you're fully loaded.:wink2:

Anyway, I wouldn't put the nose up that high, except for practicing an obstacle clearance take-off. Otherwise, use a deck-angle that is comfortable, and safe, and allow a higher cruise-climb airspeed.
Don't put your nose up in a position that will kill you if the engine quits.

 

[BrianR]

That's empty, right? Just you and the instructor. Wait til you're fully loaded.:wink2:

Anyway, I wouldn't put the nose up that high, except for practicing an obstacle clearance take-off. Otherwise, use a deck-angle that is comfortable, and safe, and allow a higher cruise-climb airspeed.
Don't put your nose up in a position that will kill you if the engine quits.

Yeah, that's what we were doing: short field over an obstacle, with simulated engine failure.

Still, with just two of us aboard, partial fuel, and a cold day, it climbs like a rocket.

 

[denverpilot]

Fun ain't it?

 

[skidoo]

Anyway, I wouldn't put the nose up that high, except for practicing an obstacle clearance take-off. Otherwise, use a deck-angle that is comfortable, and safe, and allow a higher cruise-climb airspeed.
Don't put your nose up in a position that will kill you if the engine quits.

Right, me neither.. I like to trim a bit nose down. And, with just me in it, being a bit forward cg, I still have to push.

It is really cool to be pushing nose forward with the nose attitude looking almost level and after just a few kts increase and continuing to increase in that attitude, it just goes up like an elevator! If the engine quit, it is already in a good attitude and with good airspeed.

If it doesn't quit, and after gaining sufficient airspeed, if I then relax the pressure, it will really climb well.

 

[Pilawt]

Does the CFI know that bringing the throttle back from full open leans the mixture ... ?

http://www.avweb.com/news/pelican/182045-1.html

 

[TMetzinger]

And this matters, how, in a spin recovery?

 

[N747JB]

Brian, a 182Q has a 2400 RPM redline, is the one you're flying going above 2400 on takeoff? Otherwise no reason to reduce RPM. I agree with the others, full throttle, 2400 RPM until reaching cruise altitude. :wink2: great airplane.

 

[denverpilot]

Brian, a 182Q has a 2400 RPM redline, is the one you're flying going above 2400 on takeoff? Otherwise no reason to reduce RPM. I agree with the others, full throttle, 2400 RPM until reaching cruise altitude. :wink2: great airplane.

Some of the Q's had the O470S, prior to the switch-over to the O470U, didn't they? That was a mid-model-year change of the engine, I believe.

Similar to the O470R to O470S changes mid-year in my P-model. We have an S, earlier serial numbers had the R.

 

[BrianR]

Some of the Q's had the O470S, prior to the switch-over to the O470U, didn't they? That was a mid-model-year change of the engine, I believe.

Similar to the O470R to O470S changes mid-year in my P-model. We have an S, earlier serial numbers had the R.

Yeah, not sure whether it has the S or U engine, until I am near the plane again.

 

[denverpilot]

Yeah, not sure whether it has the S or U engine, until I am near the plane again.

As someone else pointed out, easy to tell... S has the 2600 RPM redline, U has 2400 RPM. Should be able to tell just by peeking at the tach.

 

[BrianR]

As someone else pointed out, easy to tell... S has the 2600 RPM redline, U has 2400 RPM. Should be able to tell just by peeking at the tach.

Right...but the airplane is 60 miles away and, well, my memory isn't what it once was...

 

[denverpilot]

Heh. I meant when you next go pet the airplane.

 

[Pilawt]

Some of the Q's had the O470S, prior to the switch-over to the O470U, didn't they? That was a mid-model-year change of the engine, I believe.

Similar to the O470R to O470S changes mid-year in my P-model. We have an S, earlier serial numbers had the R.

C-182 had the O-470-R (230 hp @ 2600 rpm) from 1962* (182E) through 1974* (182P), up to s/n 18263475.

The engine was switched to the O-470-S (also 230 hp @ 2600 rpm) for the 182P for model years 1975* and 1976* only (s/n 18263476-18265175).

The 1977* 182Q (from s/n 18265176) switched to the O-470-U (230 hp @ 2400 rpm). Noise level was reduced and the higher-compression cylinders were more compatible with the now-universal 100LL fuel.

(*Model years do not correspond with calendar years)

 

[Jeff Oslick]

We have a 1977Q, built in late '76, so one of the first "Q"s (#154 if the above post is correct on the S/Ns). It is the U engine, 2400 RPM max. There are no Q models from the factory with the S engine. You might find someone with an STC or field approval that managed a switch. We now have a PPonk engine (470 bottom end, 520 cylinders), 275 HP, 2700 RPM redline for 5 minutes, but I flew with the stock engine for 5 years.

I've flown a few P and N models too. The reason for pulling back the prop to 2400 RPM at 500' AGL is strictly for noise control. There is NO reason to pull the MP back at the same time. This is the old "oversquare" nonsense OWT at work. If you are maintaining the climb, your MP is going to drop off fast enough that you're not overstressing anything. The pulling the prop back has a small effect on climb rate. Pulling the MP back has a large effect on climb rate. At 500' AGL you should still be climbing at Vy and trying mightily to get away from the ground asap. I have no clue why an instructor would be teaching this method. I would be tempted to find another instructor. I pull our PPonk back from 2700 to 2600 RPM at about 100-200' AGL, but that is only because I've heard it from the ground, and we're in a noise sensitive area. At 2700 RPM it'll seriously wake folks up.

Jeff

 

[Morne]

My 182 is a lot older than yours (E variant, 1962 model year, but a late December 1961 certificate). Still, she's a widebody just like you fly and a few things said already bear repeating.

1 - If you are just doing pattern work then reducing throttle at 400' AGL makes sense. A 182 will make quick work of a traffic pattern and there's no need to abuse the engine by going straight from WOT to idle. Stage your power reductions with an initial around 400', another when turning croswind and then set to your pattern speed when turning downwind.

2 - TRIM! A little nose-down trim for your take-off roll is advisable. If you get a little nose shimmy this way just pull the nose off early like you are doing a soft-field take-off.

3 - Cruise as high as you can. Leaving WOT and climbing to 9500' or 10,500' MSL is the best! Let the lower air pressure bring your power back for you.

Enjoy that bird, she's a great performer!

 

[N747JB]

Some of the Q's had the O470S, prior to the switch-over to the O470U, didn't they? That was a mid-model-year change of the engine, I believe.

Similar to the O470R to O470S changes mid-year in my P-model. We have an S, earlier serial numbers had the R.

Mine's a 77 model, and I think all Q's have the 2400 RPM redline, we had P, and I do remember it had a higher RPM for takeoff, 2600-2650? I recall pulling the prop back after takeoff, but that was 20 years ago.

 

[Pilawt]

I wondered why the switch from the 'R' to 'S' variant of the O-470 for the 1975-76 model years. Aviation Consumer said this:

"The S (1975-76) has been the most troublesome because of its revised piston ring configuration, intended to cope with the introduction of low-lead fuel."
​

 

[denverpilot]

I believe the S also introduced a couple more oil galleries that squirt oil in new and uninteresting places inside the engine, but I'll have to go pull a book or two out to see if I can find that.

I'd be curious what changed with the piston rings. Sounds like Aviation Consumer was non-impressed but there's a ton of S's operating today just fine on 100LL which have for a decade or more, and notably not many complaints as they age, from what I've seen posted at various places.

Ours ate cylinders and didn't make TBO the first time 'round with owner #1, but the logs also show the original owner didn't fly it enough, and he was in California where corrosion eats engines that aren't flown.

He appears to have put it on leaseback to a club at VNY for two years and then owner #2 found bad compressions and zero-timed the engine and later the prop.

I think a lot of the early "problems" with O470 engines eventually worked their way back to the modern mantra of "aggressive ground leaning" which often just wasn't done back then.

Flooding an engine at idle which was built for 80, with buckets of 100LL on the ground at idle, is bound to be problematic. They didn't realize that back then, though.

Jeff, it's nice to see a PPonk on this board. We're eyeballing that for what we'll probably do when this engine finally tells us it's done. Looks worth doing considering the modest performance increase for not a lot more money. What prop did you use?

TBO at our current flying rate is somewhere between 3-5 years away and we tend to think it'll go beyond, but who knows? Most do. We'll keep watching the oil analysis and inspecting filters. That seems to be the most common "help, I've fallen and I can't get up!" signs that an O470 gives before it gives up the ghost, unless you burn a valve.

 

[Jeff Oslick]

Jeff, it's nice to see a PPonk on this board. We're eyeballing that for what we'll probably do when this engine finally tells us it's done. Looks worth doing considering the modest performance increase for not a lot more money. What prop did you use?

The only modest performance increase is in cruise speed. It will run a few knots faster (149 vs. 145 KTAS at about 7,500'), but for the 2-3% increase in speed you'll blow 8-10% more in avgas. Except in early testing, we never run it that way.

The real giddyup is in climb, and we only went with the 2-blade McCauley (we did need a new prop anyway, and ours wasn't on the STC list for the PPonk in any case). We can see 1,500 FPM+ on a sea level climb with full fuel and pilot only, or two up front and 1/2 tanks. At high density altitudes it isn't a turbo, but it's the next best thing. We regularly operate out of Big Bear and Mammoth Lakes, so 8000'-9000' density altitudes aren't unusual. With me, full tanks and a couple hundred pounds of gear, I've seen 700 fpm climb out of Mammoth, and I regularly cruise around 13,500-14,500 in the Owens Valley, leaned to peak EGT at 9.5 gph and 137 KTAS.

Jeff

 

[denverpilot]

Sounds about right from what we had heard. Which Hartzell? Not the one with all the mandatory recurring ADs, I hope?

 

[John Collins]

There is no need to retard the throttle in the climb. It reduces the climb rate, leans the engine, and makes the engine run hotter (CHT and EGT). In my opinion, it is harder on the engine, not easier. A reduction in the RPM from red line can be made to reduce noise, if that is a factor. A reduction in power of X % degrades climb performance approximately twice the % amount. Overall fuel used, time to climb, trip time and distance down the road are adversely affected by reduced power climbs. I climb with full throttle, red line RPM to altitude, sort of the same way I climb with a C150, throttle forward. I lean the engine to maintain the same EGT at takeoff. I am in no hurry to reduce the RPM and have been known to climb to altitude with out any RPM adjustment until level off.

 

[SCCutler]

The only modest performance increase is in cruise speed. It will run a few knots faster (149 vs. 145 KTAS at about 7,500'), but for the 2-3% increase in speed you'll blow 8-10% more in avgas. Except in early testing, we never run it that way.

The real giddyup is in climb, and we only went with the 2-blade McCauley (we did need a new prop anyway, and ours wasn't on the STC list for the PPonk in any case). We can see 1,500 FPM+ on a sea level climb with full fuel and pilot only, or two up front and 1/2 tanks. At high density altitudes it isn't a turbo, but it's the next best thing. We regularly operate out of Big Bear and Mammoth Lakes, so 8000'-9000' density altitudes aren't unusual. With me, full tanks and a couple hundred pounds of gear, I've seen 700 fpm climb out of Mammoth, and I regularly cruise around 13,500-14,500 in the Owens Valley, leaned to peak EGT at 9.5 gph and 137 KTAS.

Jeff

Always reminded: the 182 is the Universal Airplane - does everything pretty well. Certainly a great plane for where you fly, Jeff.

There is no need to retard the throttle in the climb. It reduces the climb rate, leans the engine, and makes the engine run hotter (CHT and EGT). In my opinion, it is harder on the engine, not easier. A reduction in the RPM from red line can be made to reduce noise, if that is a factor. A reduction in power of X % degrades climb performance approximately twice the % amount. Overall fuel used, time to climb, trip time and distance down the road are adversely affected by reduced power climbs. I climb with full throttle, red line RPM to altitude, sort of the same way I climb with a C150, throttle forward. I lean the engine to maintain the same EGT at takeoff. I am in no hurry to reduce the RPM and have been known to climb to altitude with out any RPM adjustment until level off.

That's how I fly my Bo. Seems to work well for me.

 

[denverpilot]

From a discussion with an old mechanic I was referred to with a different question, but we got to talking about the airplane a little bit on the phone and this tidbit popped out...

"That O-470 engine just seems to love being run hard. Everyone I've ever seen baby it, ends up paying for it. As long as CHT is kept reasonable and you don't climb it slow with no airflow, that thing is a tank. They're not bulletproof, but they seem to enjoy wide open throttle settings."

The referral to him came with this admonition from an old friend, "I don't know, but call X at XXX-XXX-XXXX and then do whatever he says."

I, of course, shared that with his old mechanic friend who got a good laugh out of it along with hopefully a sense of pride that his reputation precedes him.

I love genuine aviation nuts. Such good people...

 

[texpilot]

I'm in the full power to cruise camp unless the POH specifically prohibits it. I have had to smack the hand of a couple of CFI's during BFR's & IPC's. I remind them to get current in engine management...until then leave it to me.

Bob