185 Winter kits

[Hornblower]

So does any one use a winter kit for a 185, ... air inlet restrictions or oil cooler restrictor plates? All the 185 I have ever flown on or worked on have had the so-called non-congealing oil coolers, but since I have never really flown one in winter, I have never seen any kind of a winter kit for them. Doesn't seen to be anything in the IPC or the operating manuals either.

Pictures would be good.

[floatingbeaver]

We had em on our 165 when it was on wheel skis. left em on till around -7c they were just your typical metal restrictor plates on the front. Ours was a 1969 model not that that should make a difference hope that helps FB.

[Hornblower]

Factory, or fab? I've seen a few 180s and 185s with rivnuts installed around the cowl air inlets, but have never seen the kit/baffle, so don't know whose it was.

[floatingbeaver]

Ours were factory cessna

[floatingbeaver]

I meant to type 185 not 165 I fly better than I type

[Commonwealth]

I'm pretty sure the ones we have for our machine are factory Cessna. We don't use them for two reasons; Even in the most extreme conditions the CHT's run close to red line and they restrict the air intake for the cabin heat. Any amount of time in flight and you are excruciatingly cold (your passengers too) and very worried about your engine.

Also if opperating on ski's, the CHT's will rise very high if you have to taxi for any length of time.

I found the engine ran just fine without them. Leave them in the hangar.

CW

[north son]

Used them on our 185's when the temp was "constantly" below -30. Worked great and
had no problems with high cht's or cabin heat. When inversions were present we
would take them off. They were factory cessna winter cowl fronts.

[Hornblower]

Commonwealth; I think you may be right, I know that in slush, especially with fixed penetration skis, you can smoke an engine if you're not careful. I was searching the internet (not always a good source of info however), and came across one guy who had tested winter kit operation by applying multiple temp probes to various cylinders, and he said the results were amazinly bad with the kits installed, uneven cooling, localized hot spots that were not there with the kits off, and multiple areas of the engine that would at times exceed the limits without it showing on the airframe installed CHT guage.

I guess I won't try to find a kit and just limit the flying for now to -25 or so.

Have you ever restricted the oil cooler air?

[Hedley]

Main thing with cold temp ops is to run the
right oil, with a very low "pour point" like
Aeroshell 15w50 (which is -42C IIRC) to
avoid congealing in the oil cooler. This
is really important.

Next problem with cold temp ops is if
oil temps never get above 150F, which
is the magic number for burning the
water out of the oil. Yes, I know 150F
isn't the boiling temp of water, but
apparently if the oil temp is 150F then
there are parts of the engine which are
hot enough to burn the water off.

Another problem with very cold ops
is excessive EGT's. This problem
arises because the air is so cold
and so dense, it leans out which is
not always the best at WOT. You
want to richen the mixture, which
incidentally will result in the engine
producing more than rated power
at sea level. Tell the pilots to leave
the throttle all the way in after
takeoff - pulling it back the first
inch will usually result in a significant
decrease in fuel flow in most all
fuel-injected engines. If the pilots
must play with something after
takeoff, tell them to reduce the
rpm to 2500, which is more for
the neighbors than the engine.

CHT's are, well, CHT's. I like them
below 400F. 350F is better. If
you can get down to 300F, well,
better for you.

[Hornblower]

Yah I know about the oil stuff, but cyl head temps I like in the green, and I suppose that cooler is better, and that I shouldn't worry about too cold cylinders (bottom of the green).

As for the burning water, ... does your wife do that too?

By the way, leaving the throttle in on a screaming IO-520 at 2850 RPM is , in my opinion, a bad Idea, and really noisy to boot.

I'll watch for high EGTs at really cold temps and power set to 25 square.

[Hedley]

By the way, leaving the throttle in on a screaming IO-520 at 2850 RPM is , in my opinion, a bad Idea

Why? The geared GTSIO-520 engines run
much, much faster than that.

really noisy to boot

I will grant you that. However, if you don't like the RPM,
back the prop off, and leave the throttle wide open.

I'll watch for high EGTs at really cold temps

you will be amazed at what you see!

power set to 25 square

This is not good. As I said before, you DO NOT
want to pull the throttle back after takeoff when
it is cold, because it will significantly decrease the
fuel flow on a fuel injected engine, which is not
what you want during the winter when you have
all that dense air creating a very lean mixture.

Leave the throttle wide open, and if you get
noise complaints, back the RPM off a couple
hundred RPM. But you do NOT want to decrease
the fuel flow when the engine is already lean,
and experiencing high EGTs at high power output.

You don't have to believe me. See for yourself.
Take off, and leave the prop all the way in (max
RPM) and pull the throttle back an inch. You will
see little or no difference in manifold pressure,
but you will observe a marked decrease in fuel
flow, and an increase in EGT.

[Hornblower]

Well they’re already really way too rich at just about any power setting with the mixture full rich so there is likely a good cushion of excess fuel, but I will watch the EGTs.

As for leaving her wide open, can’t do it, I’m not built that way, … AME background and all, … can’t bring myself to beat the piss out of an engine like you throttle jockeys. No offence, I ain’t saying you’re wrong, just not doin’ it is all.

There’s a 5 minute max on the I0-520 too, so it’s coming back to 85% or so right after floats off/safe speed. (skis in this case)

[Blakey]

This is not good. As I said before, you DO NOT
want to pull the throttle back after takeoff when
it is cold, because it will significantly decrease the
fuel flow on a fuel injected engine, which is not
what you want during the winter when you have
all that dense air creating a very lean mixture.

Leave the throttle wide open, and if you get
noise complaints, back the RPM off a couple
hundred RPM. But you do NOT want to decrease
the fuel flow when the engine is already lean,
and experiencing high EGTs at high power output.

You don't have to believe me. See for yourself.
Take off, and leave the prop all the way in (max
RPM) and pull the throttle back an inch. You will
see little or no difference in manifold pressure,
but you will observe a marked decrease in fuel
flow, and an increase in EGT.

Your engineering sounds right but you've left me climbing out with all the knobs right up against the dash! Given the scenario above, how would you reduce to a decent cruise setting?

[Hedley]

you've left me climbing out with all the knobs right up against the dash!

Yeah, I love it! Conventional wisdom says to "baby" an engine.
We fly Pitts S-2B's with AEIO-540D4A5 engines, and when I do
a solo routine, all the knobs go to the dash, and they stay there
until I'm about to turn base for landing. We have the highest
compressions on the field. It does not hurt an engine to produce
power. What hurts an engine is corrosion (from disuse), cold
starts (metal to metal and tight clearances) and high operating
temps. Keep the oil temp and CHT's and EGT's down, and the
engine will last. When an engine is producing max power, I really
believe in pumping the gas in there to keep it cool with a rich
mixture, ESPECIALLY in the winter when the air is so dense, the
mixture isn't so rich any more.

how would you reduce to a decent cruise setting?

Ok, we've got a fuel-injected engine. All the knobs go into the
dash and stay there until all obstacles are cleared. It bugs me
when pilots frantically start pulling the throttle and the prop back,
and they haven't even cleared the trees yet. I get nervous when
the hands start to blur at low altitude. Once well clear of all obstacles
(eg 500 feet) prop goes back from redline to (eg) 2500 rpm.

Throttle stays all the way in, for maximum fuel flow. This
is especially important in the winter.

The thing is, MP drops anyways with altitude. Leave the
throttle all the way in during the climb, and let the thinner air
drop the MP for you. Mixture is what you want to start paying
attention to, if you're climbing to any significant altitude, but that's
a whole 'nother story.

It's all about the oil temp, the CHT's, and the EGT's. If you
keep the metal cool, it will last longer. If you run it hot, it
will shorten it's life.

More reading:

http://www.avweb.com/news/pelican/182085-1.html

Power reductions after takeoff have many considerations and variations, so it's a little hard to generalize. In all cases, use full takeoff power until the "flight situation" has "stabilized." This is a very subjective point, since some pilots won't be fully stabilized until the airplane is in the hangar and they've had a transfusion of some type of spirits. In general, though, the gear should probably be up, the airspeed stabilized, some altitude beneath the wings, and the workload of takeoff should have abated somewhat. (On a low-IFR departure, perhaps you've turned to your initial departure heading and broken out on top of the low stratus deck.) That's the time to set whatever lesser power the limitations section of the POH calls for. Some of the larger engines have a "METO" (Maximum Except TakeOff) power, which must be set within one, two, or even five minutes of takeoff. Some go further, with an even lower setting for "Climb."

Many of our flat engines have no such limits, and are rated for full takeoff power "essentially forever." Some have RPM limits, and those should be observed. With normally-aspirated flat engines, the increasing altitude we normally see automatically reduces the power within a couple of minutes, so it is almost silly to retard the throttle, then keep adding it back within minutes.

There is a fast-growing major problem, however, and that is noise. A primary reason airports are closing by the dozen is noise at takeoff power, or more correctly, noise at takeoff RPM. It is irritating, sometimes even to people who love airplanes! In Seattle, where I live, there is a constant procession of floatplanes overhead at 1,500' to 3,000', and many of these pilots and operators don't have this picture, because they're boring holes in the sky on sightseeing and training flights at 2,500 RPM or more, engines just screaming. I can only imagine the effect on people who don't like airplanes at all, or those who feel endangered by them.

For this reason, I suggest pulling off a couple hundred RPM as soon as possible after liftoff, no matter what the book says. The difference in noise from my IO-550 and its three-bladed McCauley prop is dramatic, at the cost of just 15 HP. The Germans are so anti-noise they made Beech/TCM deliver a "special" engine on Bonanzas to be operated there, and the only change is a limit of 2,500 RPM (instead of 2,700) on the same engine. Since Beech had to do certification testing for this, we know what the HP is. The IO-550 is also quite happy at 2,500 RPM for a lot of reasons, so it's a good trade-off, I think. I usually do that as soon as the gear is up.

At the risk of being accused of beating that poor dead horse again, please, please do NOT reduce the MP to 25" after takeoff or for climb, as has so long been the accepted practice on the flat engines! EGT and CHT will go up, not down. You are not doing your engine any favors, and you may be hurting it.

Unless there is some limitation in the POH, climb at WOT (Wide Open Throttle), 100 or 200 RPM below the max (for noise), full-rich mixture and cowl flaps open (cooling), or cowl flaps as called for in the manual. You can't go wrong doing this. Monitor your CHTs, preferably on a modern all-cylinder monitor, and if any CHT goes above 380F to 400F, do something about it. There are several things you can do. The most effective one is to lower the nose and increase airspeed. Open the cowl flaps if they're not already open. Enrich the mixture, if you're ROP (or lean it more if LOP). If you're already full rich, this might be a good time to turn on the boost pump to "LOW" (if available) or "HIGH" to increase the fuel flow. With the boost running, you may get too much fuel, and the cure for this is to lean a little. All of these will reduce climb performance, but unless you're about to hit something, it always makes sense to take the "hit" on climb rate in order to keep the engine nice and cool.

No matter what your POH says, limitation or otherwise, I suggest you consider 400F an absolute redline CHT on any cylinder with a bayonet probe feeding an all-cylinder monitor (spark plug thermocouple types may show higher). There is mounting evidence that factory limits on CHT are much too high. In any event, try to keep the time above such temperatures at a minimum.

[Cat Driver]

Hedley, I can see why TC detests you.

They are afraid that you may educate the pilot group.

Keep these engine handling tips coming because very few pilots really understand how to handle engines.

Like most things in flying old wifes tales far to often trump facts.

C. E.

[SuperDave]

I'm always up for learning a thing or two about engines. A few years back I got a copy of the "Lycoming Flyer" or something to that extent. Good read, no doubt.

When I used to fly the 185 on floats I basically did as Hedley describes and never ever had a problem.
Upon floats-off and safely airbourne, without looking at the RPM gauge I would pull the prop back, just off the redline by sound only. Two or three short twists would do it. This allowed me to keep my eyes outside. After a safe airspeed was attained the flaps came up to 10 degrees as soon as safely able, while the hole time I left the throttle fire-walled. It's true, the extra fuel provided by this does cool the engine while there was no degradation of performance (as far as I could tell) by backing the prop off of the redline. Then when the dust settled and all is well, I'd set normal climb power. But initially keeping the power up and backing the prop off just a c.nt-hair seemed to work really well in the 185.

I'm by no means an expert and still have a lot to learn, but this technique worked for me. That's all I'm saying. I talked to a few of the engineers about that method, and they said it was fine too.
Remember that t/o power (and therefore your 5 minute limit) is only achieved at MAX RPM...so I don't see how one could damage the engine by keeping some extra fuel in there when the prop is aft of the redline.

[Cat Driver]

just a c.nt-hair

Black or blond?

[Hornblower]

Hedley, I... Keep these engine handling tips coming because very few pilots really understand how to handle engines.
C. E.

You must be kidding Chas, you think that a flight instructor, aerobatic, otherwise-private pile-it is the source for giving advice on things technical????

You're kidding right? I would agree that he a has a pretty good understanding of aircraft tech compared to most instructors, but really ...

[cloudrunner]

It does not hurt an engine to produce
power. What hurts an engine is corrosion (from disuse), cold
starts (metal to metal and tight clearances) and high operating
temps. Keep the oil temp and CHT's and EGT's down, and the
engine will last. When an engine is producing max power, I really
believe in pumping the gas in there to keep it cool with a rich
mixture, ESPECIALLY in the winter when the air is so dense, the
mixture isn't so rich any more.

Makes sense to me Hedley. Keep it coming

[Hornblower]

Well Hedley you’re wrong on the IO-520 D anyways. At really cold temps (-20 or so) it runs about 1420 deg with TO power, with little or no change at max continuous (maybe 5 deg. less) then drops to around 1380 at 25 square, and 1320 at cruise around 23 square + or -. So let us know what happens on your 520 powered twin. I understand that someone told you this, or you may have read it somewhere, however I think it’s incorrect. Heat makes power, power makes heat. Maybe your fuel controls and turbos need to be set up properly.

… and cloudy, … tsk, tsk, tsk.

[Hedley]

Hornblower: Hey, no problem - I'm glad you're making
a data-driven decision for your application!

What's important is that you're keeping the metal cool.

P.S. Hornblower, I realize that you may not like pilots
(or me) very much but for what it's worth I am a graduate
engineer, Queen's University at Kingston. Over 30 years
of flying and spinning wrenches on airplanes, cars, boats
and motorcycles. Please keep in mind that anything I say
here is worth precisely what you paid me for it

FWIW I have personally observed the fuel flow drop
and EGT rise with the initial reduction in throttle from WOT
on all of our Pitts (Lyc AEIO-540D4A5) and Maule (TCM IO-360).

[Hornblower]

Well, I am a pilot so it’s not that I don’t like them, I just think they aren’t the source for tech info, and probably don’t give much credence (for the most part) to an AME for whatever reason, probably cause they are the historically more revered sector of workers in aviation. And engineers (real P.engs), I have a lot of admiration for, if not respect, I just don’t think they’re always grounded in the practical world.

And there’s quite a difference between a real AME/mechanic, and a hobby guy. … different world altogether.

And I haven’t tried a Lycoming powered sled since we started this thread, but I’ll let you know what I find if I get around to it.

I thought you said once that your dad bought a 421 or something, and don’t your Pitts have EGTs?

[SeptRepair]

Hedley is bang on to his approach to educating the pilots on decreasing rpm just after take off. We have a guy ( doctor on his way to work in Vancouver) at our local lake taking off at 6:00-6:30 am in a two bladed 185 and the dumb shit doesnt even attempt to noise abate. Firewalls the f*ckin thing till he is a speck off in the distance. Completely ignorant to the people still trying to sleep. Fortunately our lake is for the most part weathered in for the winter so its mostly a spring summer time problem. Rumor has it he moved/retired, so this spring we will find out if there is peace once again on the lake in the early morning.

[Rowdy]

Hedley... you're right on.

Engines do not mind making max power.. Hell my turbocharged 2.5L will spin happily under boost (28psi) and 5000rpm forever! So long as you keep the mixture spot on and the engine temps (oil, CHT, EGT) in the green.

Detonation and pre-ignition are what hurt engines.. That and loss of lubrication....

[Hedley]

I will see if I can take a video in our TCM IO-360 Maule,
showing the fuel flow decrease and EGT rise with virtually
no MP change, when the throttle is first reduce from WOT.

FWIW: I fly (and maintain) four Pitts S-2B's with the Lyc
AEIO-540D4A5, and one Maule with the TCM IO-360 (my
15 yr old kid mostly flies it), and yes our #4 has a C421B
which I coached him into purchasing and taught him to
fly (it has TCM GTSIO-520) and I also help maintain a
Citabria and oh yeah, then there's the R985 Stearman.

Then, there's the 46 foot skater, with the twin Italian
turbocharged diesels that I hate. Only thing less reliable
than an Italian engine is an Italian turbocharged diesel
engine.

Then there's the motorcycles. You don't want to know
how many motorcycles. And the cars.

I actually spend at least 5 hours wrenching for every
hour I fly. Our chief mechanic is bugging me to finally
finish my M1, after all these decades. But again, anything
I say here is worth what you paid me for it.