I know This has been asked before, but PLEASE fix the torque

[Alec246]

I'm also a pilot, and I'm sure I feel every millimeter I move the flight control. There's a slack in the center position, so it moves maybe a couple of degrees without doing anything, but as soon as you start actually moving the aileron, you can feel the aerodynamic forces acting on the surfaces. Very precise flight is possible this way.

There are some days where the air is so smooth I take my hands off the control, keep the ball centered with the rudder, and it stays for as long as I want flying perfectly still. And there's always a little fuel imbalance, even with the Cessna using Both tanks, it never uses the same quantity on both, but I never felt the aircraft roll because of that. What I think you really can't mantain is pitch, since any small movement of one person inside the plane moves the CG, and changes the momentum, but roll is so stable.

I put the C152 on a turn, removed the hands from the yoke, and I thought I was flying a Fly by Wire aircraft, it just stayed at the same bank, perfectly flying the turn. I wish my simulators were this stable, flying is so much nicer this way.

Edit: I said stable, but actually this is neutral stability. Stable would want to return to zero bank. My bad

[Alec246]

I just can't use this plane for my IFR training in FS. It's impossible to hand fly a busy IFR approach, everytime I go set the heading bug, or change radios, anything like that, I loose control of the aircraft and almost end up with an anormal attitude! Is it really just me? Are you guys using AP on all the time? That's the only thing that would make sense to me. Try going full IFR in this Cessna, Hand Flying a busy NDB Approach.

The Seneca III from Elite Simulation is twitchy, but this Cessna is unbelievable. I can't mantain altitude, I look away for 2 seconds and I'm in a 15 degree bank. I felt the worst pilot in the world after trying this approach :/

[Hook]

One thing to check is your aileron and rudder trim. No, the C172 doesn't have these, but they may be set in the file that gets loaded as a default.

If you are using a default flight:
Look in your fsx.cfg file for a line that says SITUATION= and open the file that's listed there in a text editor.

If you are loading a saved flight:
Go to the same folder as above and load the specific .FLT file that you load from

Make sure the following values are set

RudderTrimPct=0
AileronTrimPct=0

You may be able to adjust these to get rid of any residual rolling tendency. Experiment. But try the following first.

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Make sure your fuel load is balanced, same amout in right and left tanks. If you're using fuel only from the right tank, you'll eventually end up rolling to the left. If you don't cut the fuel off when parked with the tank selector switch, some fuel can drain from one side to another without you noticing. Happened to me once.

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It won't hurt to have a passenger the same weight as the pilot. If the pilot is a 300 pounder and there's no passenger, expect a bit of left roll.

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Make sure your controls are properly calibrated.

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I have very little rolling tendency, and I usually balance it out by using fuel from the left tank until it's balanced.

Hook

[CAPFlyer]

I just can't use this plane for my IFR training in FS. It's impossible to hand fly a busy IFR approach, everytime I go set the heading bug, or change radios, anything like that, I loose control of the aircraft and almost end up with an anormal attitude! Is it really just me? Are you guys using AP on all the time? That's the only thing that would make sense to me. Try going full IFR in this Cessna, Hand Flying a busy NDB Approach.

The Seneca III from Elite Simulation is twitchy, but this Cessna is unbelievable. I can't mantain altitude, I look away for 2 seconds and I'm in a 15 degree bank. I felt the worst pilot in the world after trying this approach :/

If you're loosing control then the problem isn't the plane- it's your controls. You either have them set way to sensitively or you don't have a proper null-zone programmed. The C-172 isn't twitchy unless there are settings that are improperly set to cause it.

BTW - back to the start - if you are applying any rudder input when testing P-Factor and Torque then you have nullified the test. Since P-Factor is a yawing moment, the moment you touch the rudder you've nullified the P-Factor and thus any roll. Torque only becomes a factor on the Cessna at low airspeeds and high angles of attack. That's why the airplane has such benign stall characteristics as long as you keep it in coordinated flight through the stall. By applying the right amount of rudder, when you push up the power, you counteract the P-Factor and thus don't drop a wing or swing wildly.

[Hook]

I agree with CAPFlyer on the null zones.

Once you've checked out trim, balance and controls, we can look at how the aircraft reacts to power.

An aircraft at climb power (full throttle in the C172) will want to swing the nose left and roll left. This is counteracted with right rudder during takeoff and climb. At descent power, the opposite is true: the nose will swing right and want to roll right. Counteract with a bit of left rudder. At cruise power, the aircraft should be perfectly stable, requiring no additional inputs. You should be able to test both these conditions yourself. If you never fly at anything but full throttle, expect some left roll.

If after everything you've done, the aircraft still wants to roll left, give it a bit of right rudder when you have to take your eyes off the horizon. Just enough to keep the plane from rolling left.

Let us know how it works out, and if you do the power test, let us know at what RPM the aircraft starts rolling in either direction.

Hook

[Scott - A2A]

Hook, just to be clear, none of the 172's we flew were ever perfectly stable. There was almost always a left or right turning tendency based on power or fuel levels, even in cruise (however much less than with big power changes) Pilots make subconscious corrections with slight pressures and therefore think the plane is stable, but in our testing it was clear you could never take hands off completely or the plane would continue to wander. In real aircraft without autopilots, I end up steering with the rudder pedals to stay on course.

[Hook]

Hi Scott, and thanks.

I mentioned power levels and asymmetrical loading. The scenario I gave wasn't real life, but mathematics, and unless A2A is moving a weight randomly around the center of gravity this should eventually result in a balanced stable plane. In real life, of course, your single overweight passenger in the rear seat keeps moving from side to side and you'll never be perfect, "Flying on rails." You don't want that, either.

I think the key word is "subconscious." If you're in minor turbulence (I used to have a minimum turbulence of 1% set in AS2012 for the Cub), you won't notice small changes, but even then you'll notice larger ones. If he's actually getting 7 degrees per second, where does this fall? I expect my airplane to be stable enough not to notice, unless I've got a really unbalanced load or under unusual power conditions, and if it's not I'll be having a conversation with my mechanic.

If you take your car to a mechanic, and where formerly it was driving perfectly straight, and after he fixes something unrelated it's pulling to the left enough to notice and be annoying, and you take it back and complain and he tells you, "It's supposed to be like that," it's considered appropriate in most circles to work him over with a tire chain or length of rebar. You aren't an auto mechanic, and you haven't flat out lied to us, so you're quite safe.

In the real aircraft there's an aluminum trim tab, bendable by hand on the ground, at the bottom of the rudder. Having something like this in the hangar for people who have a lot of problems with rolling tendency, would at least give you something to point to as a solution. No, it won't be perfect, as loading and power settings will still cause instabilities, but you could set it where you wanted it and most problems should go away. Yes, I know about the bucket. I'm sure people would still complain about the slip indicator being half a ball off, if such was the case. If so, and the real aircraft does that, post a pic for them.

I've got to say that you guys have done the most incredible work. I don't have a problem with rolling myself, although I do notice it at times, but it would be nice to put the entire subject to rest.

Hook

[Hook]

Ok, after a flight test.

Balanced load, 170 pound pilot and copilot, full fuel both tanks, cruise power 2100 RPM, leaned slightly at 3000 feet, real world weather.

There was no rolling tendency at cruise power. Under full power the plane wanted to gently nudge to the left, and under descent power the plane wanted to gently nudge to the right. There was no runaway rolling tendency anywhere.

If you're getting 7 degrees roll per second with a balanced load, that's outrageous. Check your rudder calibration. Flatten the response a bit, increase the null zone if you have to. Unplug your rudder to test if you have to.

I'll eventually test some wildly out of balance loads to see what effect it has. Don't wait up. With balanced fuel and a 170 pound pilot, no passengers, there's a very slight left rolling tendency which I usually counteract by burning a bit of fuel from the left tank. It's just enough to be noticeable, not quite enough to be annoying.

As far as I'm concerned, there's nothing wrong with the aircraft itself. The only surprise here was how little rudder was needed to counteract high or low power, compared to a real life C152. My stick time in a 172 didn't include these power profiles.

Note: first flight with ASN around home in north Texas. I hit some nasty up and down drafts. Not as bad as the last time I was in a real 172 though; pilot said "500 feet per minute climb rate" and I looked over at the gauge and it said 1500. We were, how to put it, fairly heavily loaded. It was hot that day, lots of cumulus, and I think we could have shut off the engine and soared for a while.

Hook

[Alec246]

I will do some more testing using all my hardware, and maybe even shot a video, if I get these strange results again!

[Scott - A2A]

The scenario I gave wasn't real life, but mathematics, and unless A2A is moving a weight randomly around the center of gravity this should eventually result in a balanced stable plane.

In both scenerios, Accu-Sim or real life, the plane is almost always banking one way or the other. With a perfectly rigged and trimmed airplane, just the very slightest power change, you can go from a slight left bank to a slight bank to the right. Like I said above, pilots are unconsciously making these little corrections (me being one of them). I used to think planes were stable in cruise until we started doing these in-depth, controlled Accu-Sim test flights, and pretty much discovered if you go hands off for long enough, the plane will completely veer off course. This is why autopilots are so nice on long cross county flights, you really notice the difference in fatigue.

And btw it's rare to find a plane that doesn't favor one side or the other sometimes quite harshly, but we try to make our plane as neutrally balanced as possible, which means with one pilot, it will have a slight left hand tendency. In other words, our airplanes would be considered in the real world to be very nicely rigged.

Scott.

[Hook]

Agreed, Scott.

Hook

[Hook]

Next test, let's get crazy.

I had a 300 pound pilot, no passengers, full fuel, cruise at 2100 RPM. The rolling tendency was very light, no more than I remember with a 170 pounder, maybe even less. I hadn't been flying since the last update.

Ok, the crazy part: drain all the fuel from the right tank. This time the rolling tendency was quite pronounced. If I let go of the controls, I'd get 15 degrees in 7 seconds. This was with a loadout that you'd never use on purpose. Nothing like 15 degrees in 2 seconds. I thought about adding another 300 pound passenger behind the pilot, but I wanted this to be *somewhat* realistic!

If your estimate is correct, either you were holding left rudder or your rudder or aileron controls weren't calibrated properly.

One thing I did notice that seems new: that airplane loves to float on landing. Well, I'll get used to it. Also, going back to full tanks and a 300 pound pilot, descending required some left rudder. This is as expected

Hook

[Hook]

And yet another test.

280 pound pilot (why no, this isn't autobiographical, why do you ask?), no passengers, full fuel, standard cruise rate. Real world weather courtesy of ASN. Some gusty winds, just enough to keep from flying on rails.

I couldn't discern any roll, but I knew it was there because my aircraft nose kept drifting to the left after a couple of minutes if I wasn't paying attention. I'd call the corrections "subconscious" in this case. Remember, the aircraft was bouncing around gently due to wind gusts, so I was doing constant minor corrections in any case.

So here's the good part: remember that manual rudder trim tab that you can set on the ground? Well, in FSX you can set it in flight. The default keys are control-numpad zero for left trim, control-numpad period to center the trim, control-numpad enter for right trim. I pressed the keys for right trim and discovered that 5 clicks was just about enough for my "default load". Upon examining the .FLT file, the rudder trim was now set to 0.05. Considering that's measured in whole degrees, that's not a lot of trim. Don't try to use this to fix major rolling tendencies (I tested it earlier, it doesn't work well), but after you've got your aircraft otherwise balanced, it can compensate for a hefty pilot if you wish. I was pleasantly surprised to see that this worked just fine on the A2A C-172. On most aircraft, adding even one click of rudder trim is way too much and requires config file edits to be useful.

Hope this helps, and thanks again to A2A for a wonderful airplane.

Hook

[Alfredson007]

Can i add a question of my own that is a bit offtopic ...

While i am pleased with the C172s torque effects, but not so with Spitfire and RealAir Legacy (Yes, i know, not an A2A product but bear with me...) Both of these planes pull pretty heavily on the left at take off and in initial climb, but soon after the takeoff, both of these planes basicly climb straight forward. Gather little speed and the turning tendency is gone. Now, is this an FSX limitation? Because i find it VERY hard to believe that these kind of very high performance aircrafts would be so stabile at climb, especially when the C172 is not. Spitfire has got a rudder trim that is completely pointless, the Legacy has got aileron trim aswell, i doubt these tabs would be there if the planes would be so stabile to climb. And yes, all the forces are maxed out in FSX's settings.

It's almost funny how i need pretty much my rudder pedals with the A2A C172, compared to the Spit and Legacy, that require very little apart from takeoff run or very steep climbs at full power.

A2A has replaced the P-factor code from FSX with its own, will these changes eventually be on Spitfire etc? I am personally ready to pay something for such an update.

[Hook]

The side forces are greater at higher angles of attack. Try some slow flight. You should notice that aircraft often need some right rudder during the final approach because of this (and it's one reason pilots have to practice slow flight).

The reason higher powered aircraft have reduced side forces once they build up some speed is because the angle of attack is lower.

Hook