"gaits" for 172RG

[[email protected]]

Hi guys. I just got checked out in my club's Cutlass for the purpose of
getting started on my commercial rating. In that vein, I haven't done
any instrument work in the AC yet -- working on the commercial rating
is an interesting opportunity toget out of the mental world of
instrument flying and revisit those not-so-polished basic stick skills!

But this is an instrument question...

I'm going to go up today to do some approaches for instrument currency
and figured I'd do it in the Cutlass to get a feel for that plane.

Does anyone have a crib sheet for the various "gaits" of the 172RG. By
gaits I mean the various MP/RPM/configuration settings (and their
associated airspeeds) that you use in different regimes of flight;
cruise, cruise climb/descent, holding, approach outside the OM, inside
the OM, etc.

I have a rought sense for what these numbers are, but I have to admit
that I don't quite fly by the numbers the same way VFR as I prefer to
IFR.

Soon I'll ask my instructor for some instrument practice in this AC,
but it'll be nice if I have some framework of power settings before I
do so.

thanks,

-- dave j
-- jacobowitz73 --at-- yahoo --dot-- com

[Bob Gardner]

"The numbers" will stick with you better if you do the testing yourself, in
the airplane you will be using. Make a grid with manifold pressure, RPM,
pitch (in bar widths), airspeed, and VSI across the top with climb, cruise,
cruise descent, approach, approach descent, and non-precision approach
descent along the side. The key metric is airspeed, of course, followed by
VSI for climbs/descents...the other numbers are the tools you use to derive
those metrics.

Shouldn't take more than 15 minutes.

Bob Gardner

> wrote in message
oups.com...
>
> Hi guys. I just got checked out in my club's Cutlass for the purpose of
> getting started on my commercial rating. In that vein, I haven't done
> any instrument work in the AC yet -- working on the commercial rating
> is an interesting opportunity toget out of the mental world of
> instrument flying and revisit those not-so-polished basic stick skills!
>
> But this is an instrument question...
>
> I'm going to go up today to do some approaches for instrument currency
> and figured I'd do it in the Cutlass to get a feel for that plane.
>
> Does anyone have a crib sheet for the various "gaits" of the 172RG. By
> gaits I mean the various MP/RPM/configuration settings (and their
> associated airspeeds) that you use in different regimes of flight;
> cruise, cruise climb/descent, holding, approach outside the OM, inside
> the OM, etc.
>
> I have a rought sense for what these numbers are, but I have to admit
> that I don't quite fly by the numbers the same way VFR as I prefer to
> IFR.
>
> Soon I'll ask my instructor for some instrument practice in this AC,
> but it'll be nice if I have some framework of power settings before I
> do so.
>
> thanks,
>
> -- dave j
> -- jacobowitz73 --at-- yahoo --dot-- com
>

[[email protected]]

Yeah, this is what I have done in the past; generate the list myself as
an exercise. Maybe it's not a bad exercise to do in any aircraft.

-- dave j

[Dan Luke]

> wrote:
>
> Does anyone have a crib sheet for the various "gaits" of the 172RG. By
> gaits I mean the various MP/RPM/configuration settings (and their
> associated airspeeds) that you use in different regimes of flight;
> cruise, cruise climb/descent, holding, approach outside the OM, inside
> the OM, etc.

o Climb: Cowl flaps open. Full throttle throughout climb, reduce RPM to 2500
at 1,000' AGL.

o Cruise: 25" MAP or full throttle, 2500 RPM, mixture lean of peak if
possible. Keep cowl flaps open in any but very cold weather; top of Cessna
CHT green is way too hot.

o Cruise descent: 18" or 20" MAP (depending on how smooth the air is), pitch
for 500 FPM. Cowl flaps closed.

o Holding: 18" MAP, gear & flaps up.

o Initial instr. approach segments: 20" MAP, 2500 RPM.

o Final instr. approach segment (slow): Mixture rich, 17" MAP (no wind), prop
in fine pitch, gear down, 1/3 flaps.

o Final instr. approach segment (fast) Mixture rich, 19" MAP (no wind),
prop in fine pitch, no gear or flaps until 1/4 mile final, then extend gear
(don't forget!) and 1/3 flaps simultaneously, then rest of flaps below IAS
white arc.

o Landing:
-Mixture rich, 17" MAP, prop in fine pitch, 1/3 flaps & gear down at
midfield downwind.
-15" MAP abeam touchdown.
-2/3 flaps, 80 KIAS on base leg.
-Full flaps, 70 KIAS on final.
-Throttle idle, 65 KIAS over the numbers.

--
Dan
C-172RG at BFM

[[email protected]]

Thanks, this helps! I'll try these out and then fine tune as
appropriate for my club's plane.

Interesting notes about temps and cowl flaps. As it turns out, I didn't
get to do my approaches yesterday in the Cutlass because it's in the
shop. Everyone has been noting how the oil temp has been at the very
high end of the green most of the time, and the pane pretty much needs
to be flown with the cowl flaps open, and they finally decided to do
something about it. Of course, I don't know what "something" is if this
airplane is just known to run hot.

So far they've changed the oil cooler and now have decided to change
the oil temp sensor, but no change.

The CHT, by the way, seems to stay quite comfortably in the green.

thanks,
dave j


Dan Luke wrote:
> > wrote:
> >
> > Does anyone have a crib sheet for the various "gaits" of the 172RG. By
> > gaits I mean the various MP/RPM/configuration settings (and their
> > associated airspeeds) that you use in different regimes of flight;
> > cruise, cruise climb/descent, holding, approach outside the OM, inside
> > the OM, etc.
>
> o Climb: Cowl flaps open. Full throttle throughout climb, reduce RPM to 2500
> at 1,000' AGL.
>
> o Cruise: 25" MAP or full throttle, 2500 RPM, mixture lean of peak if
> possible. Keep cowl flaps open in any but very cold weather; top of Cessna
> CHT green is way too hot.
>
> o Cruise descent: 18" or 20" MAP (depending on how smooth the air is), pitch
> for 500 FPM. Cowl flaps closed.
>
> o Holding: 18" MAP, gear & flaps up.
>
> o Initial instr. approach segments: 20" MAP, 2500 RPM.
>
> o Final instr. approach segment (slow): Mixture rich, 17" MAP (no wind), prop
> in fine pitch, gear down, 1/3 flaps.
>
> o Final instr. approach segment (fast) Mixture rich, 19" MAP (no wind),
> prop in fine pitch, no gear or flaps until 1/4 mile final, then extend gear
> (don't forget!) and 1/3 flaps simultaneously, then rest of flaps below IAS
> white arc.
>
> o Landing:
> -Mixture rich, 17" MAP, prop in fine pitch, 1/3 flaps & gear down at
> midfield downwind.
> -15" MAP abeam touchdown.
> -2/3 flaps, 80 KIAS on base leg.
> -Full flaps, 70 KIAS on final.
> -Throttle idle, 65 KIAS over the numbers.
>
> --
> Dan
> C-172RG at BFM

[Jose]

> Interesting notes about temps and cowl flaps. As it turns out, I didn't
> get to do my approaches yesterday in the Cutlass because it's in the
> shop. Everyone has been noting how the oil temp has been at the very
> high end of the green most of the time, and the pane pretty much needs
> to be flown with the cowl flaps open, and they finally decided to do
> something about it. Of course, I don't know what "something" is if this
> airplane is just known to run hot.

I fly a cutlass in California with a similar problem. The top of the
green is 50 degrees cooler than actual redline temperature (it was sent
out for calibration). However, since the =only= marking on the gauge is
the green arc, knowing this doesn't help. So, I keep the cowl flaps
trailing open to stay in the green, which is the only way to know you're ok.

Jose
--
Quantum Mechanics is like this: God =does= play dice with the universe,
except there's no God, and there's no dice. And maybe there's no universe.
for Email, make the obvious change in the address.

[Part 91]

> wrote:

> Interesting notes about temps and cowl flaps. As it turns out, I didn't
> get to do my approaches yesterday in the Cutlass because it's in the
> shop. Everyone has been noting how the oil temp has been at the very
> high end of the green most of the time, and the pane pretty much needs
> to be flown with the cowl flaps open, and they finally decided to do
> something about it. Of course, I don't know what "something" is if this
> airplane is just known to run hot.
>
> So far they've changed the oil cooler and now have decided to change
> the oil temp sensor, but no change.

They need to be concentrating on the baffles and baffle seals. Even a small
leak can make a big difference in cooling eficiency.

I've spent considerable effort making sure the baffle seals are perfect,
trying to get the CHT's to stay below 380 in cruise (I have a JPI engine
monitor) with the cowl flaps closed. That helped, but I still can't close
the cowl flaps all the way unless the OAT is well below standard.

> The CHT, by the way, seems to stay quite comfortably in the green.

Yes, but the trouble is Cessna's idea of what's an ok CHT is considerably
higher than Lycoming's.

--
Dan
C-172RG at BFM

[[email protected]]

This is all very interesting, but slightly disturbing. Everyone's
flying around with their cowl flaps wide open? I guess that only costs
a couple of knots, but, it's just kind of disappointing that you can't
use them the way they're supposed to work. Well, I guess you can close
them you reduce power to descend but still keep the engine warm.

Anyhow, I have read that making sure the baffling is healthy is really
important, as the baffling was designed to direct airflow around the
engine in very specific ways, and "more open" is not necessarily
better.

I'll suggest they look at the baffles, but it's a club airplane and a
somewhat single-minded mechanic, so I may just be told to butt out.

-- dave j

Part 91 wrote:
> > wrote:
>
> > Interesting notes about temps and cowl flaps. As it turns out, I didn't
> > get to do my approaches yesterday in the Cutlass because it's in the
> > shop. Everyone has been noting how the oil temp has been at the very
> > high end of the green most of the time, and the pane pretty much needs
> > to be flown with the cowl flaps open, and they finally decided to do
> > something about it. Of course, I don't know what "something" is if this
> > airplane is just known to run hot.
> >
> > So far they've changed the oil cooler and now have decided to change
> > the oil temp sensor, but no change.
>
> They need to be concentrating on the baffles and baffle seals. Even a small
> leak can make a big difference in cooling eficiency.
>
> I've spent considerable effort making sure the baffle seals are perfect,
> trying to get the CHT's to stay below 380 in cruise (I have a JPI engine
> monitor) with the cowl flaps closed. That helped, but I still can't close
> the cowl flaps all the way unless the OAT is well below standard.
>
> > The CHT, by the way, seems to stay quite comfortably in the green.
>
> Yes, but the trouble is Cessna's idea of what's an ok CHT is considerably
> higher than Lycoming's.
>
> --
> Dan
> C-172RG at BFM

[Hilton]

Dave,

> Hi guys. I just got checked out in my club's Cutlass for the purpose of
> getting started on my commercial rating. In that vein, I haven't done
> any instrument work in the AC yet -- working on the commercial rating
> is an interesting opportunity toget out of the mental world of
> instrument flying and revisit those not-so-polished basic stick skills!
>
> But this is an instrument question...
>
> I'm going to go up today to do some approaches for instrument currency
> and figured I'd do it in the Cutlass to get a feel for that plane.
>
> Does anyone have a crib sheet for the various "gaits" of the 172RG.

As a CFI, if I were to checkout someone who holds an IR in an airplane, I
would ensure we get in some approaches and other IFR work.

Hilton

[[email protected]]

That basically makes sense, and I don't think I'd fly into IMC in this
AC without having done some instrument work with an instructor.

However, adding work that starts to feel IPCish to a checkout seems a
tad unfair. As it was, my RG checkout (also my first complex checkout)
took 7 hours with the chief pilot of my club, a very experienced and,
apparently, particular pilot. I was starting to think this was
excessive was getting ready to ask him just how much longer he thought
this would take when he signed me off. Maybe that time is normal, I
don't know. (I already had been flying the 182, so the only new system
was the gear.)

I do know that we did a lot of basic piloting stuff; a lot of takeoffs
and landings. He likes a good stall landing with the nose well in the
air; something I hadn't been doing.

As I mentioned, I'm working on my comm with this guy, so I think we'll
get around to doing some IFR stuff sooner or later, but his priority
was to get me in the air on my own so I could practice the commercial
maneuvers on my own between lessons.

-- dave j

> As a CFI, if I were to checkout someone who holds an IR in an airplane, I
> would ensure we get in some approaches and other IFR work.
>
> Hilton