Having some fun with this overly floating C172

[Igor]

You can fly the plane by the realistic numbers and she'll do pretty well, when flying we are told not to focus too much on them but for a basic circuit. Short field as per the POH for the 172R/S (our R's have the S prop so basically the S).(STOL mixed with checks from the local flight school) Flaps 10 degrees, apply brake, set max power when RPM static and if it's high enough release brake check t's&p's, check airspeed alive. Rotate at 51 knots set climb for 55 knots then 60 knots when clear of 50ft obstacle @ 60 retract flaps then continue for best rate of climb 75kt full throttle if no other obstacles (After T/O check flaps up, gear up, power set, t's & p's green, switches off (landing light), check behind for centreline). Downwind (brakes check, undercarriage down, mixture full rich, fuel on both and sufficient, instruments set, switches on (landing lights), harnesses check) downwind call, fly 2100RPM flaps 10 degrees when parallel to aimpoint on runway, reduce to 1500RPM & down to 75knots during base turn (shouldn't lose alt until flying base so power varies we use it in order to get slow enough to deploy flaps 20) maintain 75kt and flaps 20 on base. Final turn, flaps 30 degrees approach 60kt, (pitch full fine if applicable, undercarriage down, flaps as desired, cowl flaps open if applic, carb heat off if applic, clearance received) aimpoint is the start of the runway (not the numbers) adjust speed, pitch to maintain correct attitude and 60kt. Set idle power, look to the end of the runway fly level and develop lift nose up to the end of the runway. When on the ground apply hard brakes (don't skid), flaps up, apply backpressure on the stick.

The 172 does have a tendency to float, with experience you can reduce it a little bit, but it also depends on the weather conditions, if you have gusting winds and heavy turbulence you might have to fly a 65 knot approach speed which will give you allot of float with 30 flaps. It also depends how much time you give yourself to develop, if you didn't pull that power back at the right time and try to put her down too fast without developing enough you'll risk giving the oleo more of a workout then it's willing to take. Frightening both for you and the people onboard (you can ask my instructor ) I violated this rule more times then I would like to count when I first started landings in the 172. I cant stop but marvel at what a masterpeice A2A made with their 172. I was coming up for my first solo checkride feeling completely devastated at my lack of knowledge holding off properly, and it's very rare that I can say this but flying this plane in the sim helped me fly it better in real life, I practiced and practiced holding off until I heard that stall horn while being low enough for a softer landing. You will find no greater joy then in learning to fly the aircraft accurately in the sim, and seeing how similar it is to its handling in real life either as a passenger viewing on, or the pilot.

Sorry for the essay guys, I know theres allot of people here probably more knowledgeable than me but I hope some of my experience might be able to help out some of the newer guys wondering about the proper methods of ops . The POH for the 172 is very helpful for allot of these things but if anyone has any questions feel free to PM me and i'll get back to you .

Edit: We were told to reset our trim every time we change speed, so going from the 60kt climb you would be trimmed for 60, to increase to 80 we would lower the nose, let airspeed climb upto 80 then set the trim, some pilots set the trim slowly as the airspeed changes. It is allot more notable in real life though, the force required to push back on the stick while executing a glide approach go around is quite tough to push against and the effect of slipstream plays a large factor in that example as well, I normally start trimming straight away. The only trim setting we ever actually set is T/O trim in the pre start/pre takeoff/after landing check.

[Great Ozzie]

Can't say anything about the actual trim position in real C172R/S on approach, but I understand that Scott has confirmed it's on the same mileage as in real aircraft they tested.

I agree Esa.

In the ten years I was actively flying / instructing... I have never heard so much talk about trim position as I have here. In fact, I cannot recall one instance where someone discussed the actual position of trim wheel. This includes all the discussions of flying with other pilots and instructors & all the reading I have done regarding Aviation (books, magazines, web articles etc.).

The ONLY time I have ever concerned myself with the position of the trim wheel was prior to take-off. Very important because one does not want to be fighting the airplane for control during departure.

But I find flying with certain trim settings somewhat counter-intuitive. In gliders, I keep my free hand on the trim almost constantly. When I did some flying in C150, I was also intuitively trimming whenever I changed pitch or power. The instructor was not displeased at all about that. I would disagree if an instructor told me to set a certain trim setting and leave it there (in the air of course!).

Yeah, I would say it would be nutty to shoot for a certain trim position. The trim is there to relieve the control (elevator) force one has to apply based on pitch / power. For example, departing the runway (no obstacles) after accelerating to near Vy, pitch the nose to where I know it will give me Vy. Then trim as necessary so that I am not having to apply any force on the stick (yoke).

Same goes with the power, I was told to fly it to the runway in a right glide angle and speed. Not to care about which RPM or trim setting stabilizes it there.

These are the keys... ON Glidepath... ON Airspeed. The glidepath part becomes a judgement thingy (experience) but you use 'the Goldilocks Method'... not too high... not too low... but just right. Just right means you aren't diving for the runway (blowing thru your approach airspeed) or getting so low that if the engine did fail, you cannot make the runway. It is hard to do this in the sim.

Btw, regarding airspeed control... one needs to work at getting airspeed within plus / minus a couple knots of the intended speed. Trimming appropriately goes a long way here to make that happen.

The one thing I will say about rpm; I want to use 'the Ron Popeil Rotisserie method' i.e. "Set it and Forget it!". That is, I do want a basic rpm I can set and for the most part leave it alone (depending on wind, etc.). My primary instructor would say, "No one likes a throttle jockey". And 'normally, one does not need to be a throttle jockey in the pattern.

aimpoint is the start of the runway (not the numbers)

Hi Igor,

I have never heard of aiming for the runway threshhold... would you explain why this is used?

When on the ground apply hard brakes (don't skid), flaps up, apply backpressure on the stick.

This is part of a short-field technique. Normally, I let the plane roll out unless I know I need to vacate the runway in short order.

you didn't pull that power back at the right time and try to put her down too fast without developing enough you'll risk giving the oleo more of a workout then it's willing to take. Frightening both for you and the people onboard (you can ask my instructor )

More of a workout or worse. Yes, it is attention getting.

I was coming up for my first solo checkride feeling completely devastated at my lack of knowledge holding off properly, and it's very rare that I can say this but flying this plane in the sim helped me fly it better in real life, I practiced and practiced holding off until I heard that stall horn while being low enough for a softer landing.

Good man! Good for you! Very cool to hear a story such as this. Way to stick with it.

Edit: We were told to reset our trim every time we change speed,

Yes... generally speaking, if I am having to apply a control pressure, then that pressure gets trimmed off.

The only trim setting we ever actually set is T/O trim in the pre start/pre takeoff/after landing check.

Precisely... set for takeoff (actually I never messed with the after landing).

The only other comment Igor, is in reference to flying the pattern (which goes more toward flaminghotsauce).

My preference:
I like a 90kias downwind.
Abeam the Numbers: *Set Power* - 10°flaps - pitch to 80kias, then start descent.
45° off the Numbers: Turn Base - 20°flaps - pitch to 70kias
Final: 30°flaps - pitch to 60kias
Notes:
Trim as necessary to relieve control pressure.
*Set Power -> I find 1400rpm works well.
Departure: I do not make my turn to crosswind until 400' agl (unless it is a very long runway, then wait until clear of the departure end)

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Here's an article from Flight Training magazine The Quest For The Perfect Landing that I think will be useful.

http://flighttraining.aopa.org/students ... rfect.html

As Bob Hoover says in the article, the secret is to, "Work real hard at it."

-Rob O.

[Scott - A2A]

Several. From a 1964 6 banger to a 1976. I'm not sure all the model letters. The '76 was the latest model year I flew. There were 72's and a '67 I think.

This is what I suspected. You were flying a much lighter 172 (the ones that were made prior to Cessna ceasing production then resuming again). Also, you likely had a Lycoming 320 engine with a 2,700RPM redline (the C172R has a Lyc 360 with a 2,400RPM redline), so all of those numbers you are flying by are too high for the C172R. Also, you may have had 40 degrees of flaps, rather than the lower 30 degrees on the later model 172's like ours.

In other words, the entire time you have been in the pattern using those numbers, you have had both too much power and too little drag, which accounts for the fast, floating approaches.

Scott.

[flaminghotsauce]

My preference:
I like a 90kias downwind.
Abeam the Numbers: *Set Power* - 10°flaps - pitch to 80kias, then start descent.
45° off the Numbers: Turn Base - 20°flaps - pitch to 70kias
Final: 30°flaps - pitch to 60kias
Notes:
Trim as necessary to relieve control pressure.
*Set Power -> I find 1400rpm works well.

Rob, sounds like your approach is just like mine, except for how mine is handling. I took my hands off the yoke with full flaps, and massive trim down, rpm down to 1000, and floated UP to stall. I"ve tried 1400 RPM, it's way too much. I'm considering reinstallation of the 172, because as I read through your procedures, that looks like what I'm doing. Huge pitch up with each notch of flaps.

Scott, the '64 6 cylinder was very nose heavy compared to the rest, but yes, they were all indeed 2,700 rpm to the red. It doesn't explain what's happening though. I slow to 80, put in a notch of flaps, just like Rob does, but I put in a lot of nose down trim. 2nd notch on base, lots more nose down trim, turn final, LOTS more down trim with full flaps, and I"m still shoving the yoke in, fighting it all the way. I rarely ever used 40 degrees of flaps, most of the time only going two notches unless the wind was light to non-existent I'd go to 30.

AS far as the trim discussion, no I don't ever look at the trim setting until I'm getting ready to launch. That includes touch and goes. Every time I do a circuit, and the airplane is properly trimmed, the trim is perfect for takeoff. EXCEPT in the A2A, it's halfway between the takeoff setting and the top, so I have to roll it WAY back before I do another circuit. It acts like it's WAY WAY too light.

Does this sound like a re-install would correct this? Any settings I might check? I don't think it's behaving the way everyone describes.

[Scott - A2A]

Flaminghotsauce,

I would forget any experience on older Cessna's to the C172R regarding trim, as the 172R is about 250lbs heavier.

Here's a pict from us during a flight test in a Cessna 172R right after touching down:


Here's a screenshot I took in the sim, equally loaded, right after touching down:


Scott.

[Igor]

aimpoint is the start of the runway (not the numbers)

Hi Igor,

I have never heard of aiming for the runway threshhold... would you explain why this is used?

When on the ground apply hard brakes (don't skid), flaps up, apply backpressure on the stick.

This is part of a short-field technique. Normally, I let the plane roll out unless I know I need to vacate the runway in short order.

Yeah we only set aimpoint at the runway threshold when we are performing a shortfield landing, otherwise it is on the numbers . Yeah I put a short field circuit as we were taught to do it thought it might help with some floating issues . Thanks for the advice and i'll definitely take a look at that article im about to go for my GFPT so every little bit helps, I fly out of YPJT it's nice to meet a fellow Aussie.

[Great Ozzie]

Yeah I put a short field circuit as we were taught to do it thought it might help with some floating issues .

Thanks for that explanation Igor.

Your enthusiasm is contagious, and the posts I have seen of yours makes me wonder if you will one day get your CFI.

Thanks for the advice and i'll definitely take a look at that article im about to go for my GFPT so every little bit helps,

Yes... I have found that it is good to incorporate multiple sources into one's flying technique... you take what you think is the best that works for you.

I fly out of YPJT it's nice to meet a fellow Aussie.

Ah... the 'Great Ozzie' nick is something I usurped from a friend of mine (it was his nick on chess forums). In this case 'Great Ozzie' is a green monster from some game he played.

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Btw regarding this "float"... I do not carry power into the flare (dvm mentioned this in another post regarding a friend of his) as being slightly high i.e. runway made, you can maintain 60kias "over the fence".

Now, with the upcoming Cherokee with the old Hershey Bar wing... I am sure that will be a different story. But as far as this plane is concerned w/ just the 30° of flap, you certainly can expect a little float.

@ flaminghotsauce... yeah something does not sound right with your "performance". 1000rpm would not be nearly enough for a 1000'agl "normal" pattern for me; I don't have to fight the stick... just bleep in (button on the stick) a bit of trim when slowing to 80kias and just a bit more with the addition of flaps / airspeed changes.

Fwiw, looking at Scott's pic... my trim on landing was very close to that (mine was abeam the "K").

-Rob

[flaminghotsauce]

Yeah, no. My trim wheel is nearly to the top letter. I did some more circuits today, and tried 1400 RPM initially and let it bleed down to 1300. I was rolling in the nose down trim nonstop while the flaps were coming in. I was able to fight off the big float. I have been putting the trim in "takeoff" setting about where your pic shows, Scott. However, after two more landings with the trim wheel all the way up to the "T", I left it there for the next takeoff roll. As one might expect, I had to pour on massive trim adjustment to get it back close to where it needed to be.

Your picture shows what I'm expecting to see. Both pics are showing it where I think it should be.

Settings? I don't know. Perhaps I should look at something in particular?

[motoadve]

Excellent thread.
Real pilot here, more than 1,000 hrs mostly in a 182,about 30 in a 172.
172,s do float if you are a bit fast, also the approach speed for full gross weight should be different than if you come a bit light, the POH speeds are for full gross, so we need to take that into consideration, or else it will float.

Trim is true, not as important in a 172. But very important in a 182 because its too nose heavy.
Here a couple of short field landings in my 182


http://m.youtube.com/watch?v=jAO39NLkogw



http://m.youtube.com/watch?v=v-AnhvZColU

[catmar1944]

Excellent thread.
Real pilot here, more than 1,000 hrs mostly in a 182,about 30 in a 172.
172,s do float if you are a bit fast, also the approach speed for full gross weight should be different than if you come a bit light, the POH speeds are for full gross, so we need to take that into consideration, or else it will float.

Trim is true, not as important in a 172. But very important in a 182 because its too nose heavy.
Here a couple of short field landings in my 182


http://m.youtube.com/watch?v=jAO39NLkogw



http://m.youtube.com/watch?v=v-AnhvZColU

Thanks for the uploads great video's and great flying, not a lot of wing room on that last landing strip.

[domini99]

My landings are usually worse, i always put her down left or right from the centerline

[mer8771]

In the 172 and 180 I use 55% mix until I'm lined up for take off then full mix for the take off. 55% at 3500 is close to max gas temp but that's the only thing that seam to not be accurate in the sim. I say that cus after a few flight I did to try to understand your question it was always different for a few reasons. Weather, wind speed, and direction changed all but the mix. Had all the winds been head winds instead of cross winds this might not have come out this way for me. My dad tough me to fly by feel more than the numbers but in a sim that's kinda hard I know. winds 5-12 knots rain on one landing maybe a 5 knot component at most for all landings.