Cherokee to 172 transition?

Bonchie

Bonchie

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Bonchie
Looking at a 1/15th share in a 172M flying club (160hp w/ power flow).

How long does such a transition usually take? Hour or so?
 
An hour at best,just have to get the landing speeds down.
 
Bonchie said:
How long does such a transition usually take? Hour or so?
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Depends on the pilot's prior experience. One hour might get you to where you can take it around the pattern safely, but budget 2-4 hours total ground and flight time for a true aircraft transition training program IAW FAA recommendations. Might need a bit more for IFR if you're unfamiliar with the avionics, too.
 
Ron Levy said:
What makes you think that? I can't think of any reason a 172 would be either more or less likely than a Cherokee to drop a wing in a stall.
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Reading to much stuff on the internet probably.

The Cherokee is ridiculously stable and docile in a stall. I've always heard a 152 and 172 will drop a wing more easily.
 
Bonchie said:
Reading to much stuff on the internet probably.

The Cherokee is ridiculously stable and docile in a stall. I've always heard a 152 and 172 will drop a wing more easily.
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The 172 is about as stable as the Cherokee in a stall; however, the stall break is a lot sharper and more pronounced.
 
The engine start procedure is different. Remember to use the fuel for takeoff, landings, and switching tanks. Remember to switch tanks as there is only left, right, and off. The stalls are a lot gentler and you might not even recognize it. Read the POH for the differences in systems. I'd say a few on the ground for systems and procedures and about an hour in the air and you should be fine.
 
jordane93 said:
The engine start procedure is different. Remember to use the fuel for takeoff, landings, and switching tanks. Remember to switch tanks as there is only left, right, and off. The stalls are a lot gentler and you might not even recognize it. Read the POH for the differences in systems. I'd say a few on the ground for systems and procedures and about an hour in the air and you should be fine.
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You are describing the Cherokee. I'd be going from a Cherokee to a 172.
 
Bonchie said:
You are describing the Cherokee. I'd be going from a Cherokee to a 172.
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Oops. Man its a slow Sunday for me. Good thing is you don't need to switch tanks anymore. There is a lot less control over the flaps. I prefer the Johnson bar. Stalls are a lot more fun
 
jordane93 said:
Oops. Man its a slow Sunday for me. Good thing is you don't need to switch tanks anymore. There is a lot less control over the flaps. I prefer the Johnson bar. Stalls are a lot more fun
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Yeah. I think I'm gonna miss the trim being between the seats as well.

This 172M is a fine machine though. They've done the 160 conversion with power flow. 120 knots at cruise (faster then the Cherokee I've been flying, which I plan 112kt for and almost never actually get to). Bigger useful load. Garmin 530, club XM subscription, and autopilot as well.
 
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Bonchie said:
They've done the 160 conversion with power flow. 120 knots at cruise
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I'd believe 120 knots TAS cruise in a 180HP 172, but not a 160. I'm not seeing how that's possible unless you're cruising well over 75% power. If you think you're getting 120 knots TAS at 75% power in a 160 HP 172M, check the tach -- I'll bet it's reading 150 RPM low.
Bigger useful load. Garmin 530, club XM subscription, and autopilot as well.
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Nice stuff to have.
 
Ron Levy said:
I'd believe 120 knots TAS cruise in a 180HP 172, but not a 160. I'm not seeing how that's possible unless you're cruising well over 75% power. If you think you're getting 120 knots TAS at 75% power in a 160 HP 172M, check the tach -- I'll bet it's reading 150 RPM low.
Nice stuff to have.
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It's a 160HP engine + a powerflow exhaust. I've seen a 172K setup the same way push 124 KIAS, so 120KTAS cruise is reasonable.
 
Ron Levy said:
I'd believe 120 knots TAS cruise in a 180HP 172, but not a 160. I'm not seeing how that's possible unless you're cruising well over 75% power. If you think you're getting 120 knots TAS at 75% power in a 160 HP 172M, check the tach -- I'll bet it's reading 150 RPM low.
Nice stuff to have.
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The club plans for 120kts at 75% and flightaware on the plane shows consistent with that. I think the powerflow adds to it.

But even if it's really 118, 115, or whatever, it's still faster then the Cherokee 140 (also a 160 conversion) I'm flying that barely does 110 in calm conditions. Plus the backseat is actually usable.
 
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warthog1984 said:
It's a 160HP engine + a powerflow exhaust. I've seen a 172K setup the same way push 124 KIAS, so 120KTAS cruise is reasonable.
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I can believe 124 knots full throttle at SL, but not in a 75% power cruise, and the PowerFlow exhaust will not increase speed at the same power setting (i.e., RPM at a particular DA). You might not need as much throttle to get that 75% power RPM with the PF exhaust, but to get more speed at the same 75% power, you have to reduce drag, and the PF exhaust doesn't do that. Increasing power from 75% of 150 to 75& of 160 is only going to increase airspeed by about 2%. Since a stock 172M is about a 110 knot plane at 75% power, that means maybe 112 KTAS with the 160HP STC at 75% power with the 160HP STC. So, if you think you're getting 120 KTAS at 75% power with that 160HP STC, check your tach -- you're probably running a lot more power than you think.

What you will get in abundance with that STC and PF exhaust is a significant increase in climb rate, since every 1 HP extra gives you about 14 ft/min more climb rate in a 172 at the same climb speed.
 
It's a 1976 model, which is faster then the earlier Ms.

The M is a 115kt plane on paper without the conversion. The 76 model is 3 knots faster then that on paper, no conversion.

One of many sources: http://www.premi-air.co.nz/singlespecs.asp?Model=Cessna+172M

So with the 160hp conversion, them planning for and achieving 120kts makes sense.
 
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Ron Levy said:
What makes you think that? I can't think of any reason a 172 would be either more or less likely than a Cherokee to drop a wing in a stall.
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Former Cessna Manager of Aerodynamics and Flight Test William Thompson (Cessna - Wings for The World, p. 41) described a couple of reasons:
"Another 1971 change [for the 172] was moving the landing light from the left wing leading-edge to the engine cowl. [...] [T]he advantages were removing a possible source of airflow separation on the left wing (and occasional wing-dropping tendencies at the stall) and,of course, improved light intensity with the absence of a Plexiglass cover."
[emphasis added]

​
Yes, I remember occasional wing drop in early (1970 or earlier) C-150s and C-172s with the left-wing-mounted landing lights. Certainly nothing hair-raising about it, though.

Interesting to note that Cessna moved the landing lights back to the left wing in 1982, likely because of poor bulb life from vibration and heat in the cowl. But the wing cutouts were now smaller and somewhat further inboard than they were in the pre-'71s. Maybe flight testing found a way to mitigate the airflow separation issue.

Thompson went on to mention wing-drop in '73 and later models (p. 42):
"The popular drooped (cambered) leading-edge was introduced by customer demand in the 1973 C-172M. [...] Contrary to one's expectations, in some cases the stall characteristics (wing dropping) were compromised by the drooped leading-edge because of reduced aileron effectiveness afrer a sudden and more complete airflow separation over the wing surface ahead of the ailerons at the stall."
[emphasis added]
​
 
Bonchie said:
It's a 1976 model, which is faster then the earlier Ms.

The M is a 115kt plane on paper without the conversion. The 76 model is 3 knots faster then that on paper, no conversion.
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On paper, yeah. But after 45 years of flying legacy 172's, I know full well they don't make book cruise performance.
One of many sources: http://www.premi-air.co.nz/singlespecs.asp?Model=Cessna+172M

So with the 160hp conversion, them planning for 120kt makes sense.
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Not to me, and I suggest you don't plan on it either, unless and until you confirm this plane actually flies this fast on 75% power, with the power confirmed by calibrated tach and fuel burn.
 
Pilawt said:
Former Cessna Manager of Aerodynamics and Flight Test William Thompson (Cessna - Wings for The World, p. 41) described a couple of reasons:
"Another 1971 change [for the 172] was moving the landing light from the left wing leading-edge to the engine cowl. [...] [T]he advantages were removing a possible source of airflow separation on the left wing (and occasional wing-dropping tendencies at the stall) and,of course, improved light intensity with the absence of a Plexiglass cover."
[emphasis added]

​
Yes, I remember occasional wing drop in early (1970 or earlier) C-150s and C-172s with the left-wing-mounted landing lights. Certainly nothing hair-raising about it, though.

Interesting to note that Cessna moved the landing lights back to the left wing in 1982, likely because of poor bulb life from vibration and heat in the cowl. But the wing cutouts were now smaller and somewhat further inboard than they were in the pre-'71s. Maybe flight testing found a way to mitigate the airflow separation issue.

Thompson went on to mention wing-drop in '73 and later models (p. 42):
"The popular drooped (cambered) leading-edge was introduced by customer demand in the 1973 C-172M. [...] Contrary to one's expectations, in some cases the stall characteristics (wing dropping) were compromised by the drooped leading-edge because of reduced aileron effectiveness afrer a sudden and more complete airflow separation over the wing surface ahead of the ailerons at the stall."
[emphasis added]
​
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Thanks for that information. However, my experience is that with most pilots, their feet are more important than the design in avoiding wing-drop at the stall. :wink2:
 
Since no one else has mentioned it, probably the biggest difference will be the larger flaps. If you were flying a Hersey bar Cherokee they can come down at similar angles but it is a bit different sight picture. The tendency to trim stall on a go around with full flaps is something you need to be prepared for, essentially if you are trimmed for approach with full flaps and add power the 172 will have a strong tendance to nose up which can cause the plane to stall if you do not forceable hold the nose down until the flaps are retracted some or forward trim is added.

Brian
 
Ron Levy said:
I can believe 124 knots full throttle at SL, but not in a 75% power cruise, and the PowerFlow exhaust will not increase speed at the same power setting (i.e., RPM at a particular DA). You might not need as much throttle to get that 75% power RPM with the PF exhaust, but to get more speed at the same 75% power, you have to reduce drag, and the PF exhaust doesn't do that. Increasing power from 75% of 150 to 75& of 160 is only going to increase airspeed by about 2%. Since a stock 172M is about a 110 knot plane at 75% power, that means maybe 112 KTAS with the 160HP STC at 75% power with the 160HP STC. So, if you think you're getting 120 KTAS at 75% power with that 160HP STC, check your tach -- you're probably running a lot more power than you think.

What you will get in abundance with that STC and PF exhaust is a significant increase in climb rate, since every 1 HP extra gives you about 14 ft/min more climb rate in a 172 at the same climb speed.
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I'd like to see the takeoff and climb performance out of a 160hp 172 that does 124knots, my guess is it sucks.

(I can't run full throttle , level at altitude due to RPM limitations.)
 
Similar to brcase's post:

The flaps on a 172M are much more effective- while flaps 25 is the short-field technique for a Piper, in a Cessna flaps >10 will just kill your lift.

And since it still has the full flap travel: Do NOT use Flaps 40 on approach unless the intent is to go straight down and you don't care about going around.
 
You also need to prepare yourself to lose the runway on every turn in the pattern. Learn how long the turns take, because you can't see anything to the side in a bank.

When practicing or taking a Flight Review, clearing turns are important. Those are things that don't bother us low wing types much.

BUT you will be able to put your folding chair under the wing for airshows and fly-ins, and be a little more comfortable in the shade. Haven't figured out how to do that in my Mooney yet. :wink2:
 
I trained on DA20's, then transitioned to PA28-161's then to a 172SP.

I found the 172SP supremely docile compared to the DA20 (obviously) and more comfortable to fly than the PA28-161, primarily because of front visibility and ease of entry/exit.

In terms of how to fly it, it didn't sink as fast when power was retarded as the PA28, and a good round out was critical to a good landing. Round out at 60 or so kts and let it settle while flaring. Pretty easy.

I'm now in a DA40 and it's nice to be in the feisty Diamond again.
 
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