c172 Flight Characteristics on Landing

[joerox135]

Hi all!

I'm a certified private pilot and I have several hours in a real 172R just like you guys have made. I really like the plane and all the modeling and designing and functions of the aircraft are wonderful! I have one question/concern that I would like to ask about. When I fly in real life in a pattern, once abeam of my landing point, I reduce power to 1500 RPM, slow down to 80 kts (so I'm below the white arc) then apply the first notch of flaps (10 degrees) and begin a decent to maintain around 75-80 knots. On base, after the turn, I apply the second notch of flaps (20 Degrees) and pitch to maintain 70 knots. Once on final, I deploy all flaps and maintain around 65 knots and pull the power once I know I have the runway made and float down to touchdown...etc. My two concerns are 1. the angle of decent needed to maintain a certain airspeed on descent. I feel in the a2a version, I'm really having to pitch my nose down to an extreme angle to maintain a certain airspeed as well as maintain my decent patch, especially on final with full flaps. My second concern is that the plane does not flare properly at around 60 knots when I round out and begin my flare. It's almost way too easy to balloon on final and gain altitude. At 40 knots, the a2a begins to flare properly which seems quite unrealistic because I usually touch down around 50 knots or so. So basically, for my approaches, I'm at an extreme nose-down attitude, then my when I round out, I balloon and gain altitude (with power all the way out) and I'm basically floating down the runway till I get to about 40 knots, then the plane finally begins to sink into the runway. If someone could help me out with maybe a fix for it (by the way I'm updated to v2) or tell me how to combat this, that would be wonderful! I really love the plane but I'm not too satisfied with it's flight characteristics on approach. It seems to me that between the a2a and default 172 in FSX, the default does a much more realistic job on approach (from what I'm noticing). Anyway, once again, great aircraft without a doubt! If someone could help me out, that'd be wonderful!

Joe

[Scott - A2A]

Joe,

It sounds like this all comes down to getting used to the different sensitivity of the controller as our flight model simulates the full throw of the yoke, which is unlike many simulated airplanes (which reduce authority to make the plane easier to fly).

Here is a great short video from Rob Osborne (CFI) demonstrating a landing landing and flare using our plane:
[youtubehd1002 606]http://www.youtube.com/watch?v=xVYuKdLcEk4[/youtubehd]

Scott.

[Oracle427]

As a pilot myself, and there are many others here several of which are CFIs, I took issue with this area of the performance of the A2A 172R. I usually fly a 172N and 172S when using a 172.

Setting aside differences in controller setup, sensitivities, etc.

I thought that the A2A 172 floated too much at too low an airspeed, not just during the landing but also demonstrated too low a sink rate at slow airspeeds down to 45KIAS with flaps fully extended at idle power. This was matching my usual payload of single passenger with approximately 30 gallons of fuel and very close to standard conditions at 15C and 29.92 In Hg.

So I finally decided to test it in the real thing and very closely monitored the performance at altitude and later as I did landings at these same very low airspeeds in calm weather. What I discovered was that my memory and perception was incorrect and the A2A 172 modeled the performance very closely to the real aircraft.

The things I noted were that a 172N with 2 passengers totaling 290lbs with about 30 gallons of fuel will stably descend at about 400FPM with 30 degrees of flaps at idle power at a stable 45KIAS. I expected a much higher sink rate because it looks like you are descending faster when in fact you are simply descending on a more vertical profile. You can ride this down and still have enough energy to flare and land, but only just. At this speed, there is very little chance of ballooning as you will very quickly drop below 40KIAS as you pull up to arrest the descent and immediately begin the flare. I felt very comfortable doing this exercise as I started at altitude to get used to the handling in the 172 and also have received instruction in landing at these low airspeeds for maximum performance.

A typical approach at 65KIAS will have you gliding over the runway at closer to 50 KIAS with plenty of energy left to balloon a dozen feet into the air with a very gentle pull of the yoke as can be observed all day at airports with busy training operations.

I think the sim gives us different visual cues and definitely lacks the physical cues that we learn to rely upon in the real aircraft. I find the simulator consistently harder to fly for this reason, but have learned to respect the A2A 172 for its accuracy in the limited areas I have decided to test for myself.

[crimson apple]

I have 14 hours in C172R at my local flight school. In the sim the flaps generate way too much lift and floats at low air speed, even with calm no wind day in the sim with max flaps the aircraft does not want to land even below 45 kts.

[joerox135]

Hey guys,

I really appreciate your replies and thoughts on this topic! After doing a little browsing, I've edited the cruise lift performance in the aircraft cfg from 1.0 to 0.5 which seemed to drastically help. It seems like the aircraft performs like it does realistically with descent rates and such. In regards to the airspeed issue I mentioned, it seemed that it correlated back to the lift and now seems more realistic and easier to maintain approach speeds when I fly.

Thanks!

Joe

[Lewis - A2A]

Remember that editing the cfg can have adverse affects through the entire flight model. The simulation performs very near if not exactly like the real one as confirmed from our flight test programs using direct Video recording as we soon discovered as Oracle mentions that memories even minutes after the event are often very abstract to what actually is happening with the aircraft.

thanks,
Lewis

[Oracle427]

I'm curious what results you have achieved and what was your criteria. Did you do it by "feel"or use hard data. Like I said I thought the same as you guys but was proven totally wrong when I tested it for real.

As Lewis has noted edits to the configuration files may yield odd results as Accusim operates outside FSX.

[Scott - A2A]

Guys, it really doesn't matter. If Joe wants to edit the plane to make it easier to fly on his system, then that's fine. He just needs to be aware that the performance will be compromised.

Scott.

[Rocket_Bird]

I think the sim gives us different visual cues and definitely lacks the physical cues that we learn to rely upon in the real aircraft. I find the simulator consistently harder to fly for this reason, but have learned to respect the A2A 172 for its accuracy in the limited areas I have decided to test for myself.

In a way it kind of does. I'm a fairly short person, and I feel like a tall person in the A2A C172 for some odd reason .

I used to be an instructor on the 172, and I did a lot of my training on it as well. Interestingly, I never flown the R model, though I've dabbled with the M, N, Q, and SP models). Behind the desktop, there are certainly differences in feel, but when it comes down to it, it's really about how it actually compares to the numbers. Before the A2A C172, I used to test the heck out of the Carenado 172N. Particularly for landing, I would do power-off 180 precision glides, the same way they are done in real life, and see how far I float down the runway given a precise aim point, vref, and flap setting. At full flaps, I should be able to touch down about 500-600' from my point of aim assuming winds calm (at my home airport). I actually give Carenado a lot of credit for their model, because it's pretty close to the numbers.

I took the A2A C172 for a spin, and did the same power-off 180 approach, and it wasn't far off. By comparison, the default Cessna 172 I find was a bit unrealistic, as it tends to drop like a brick once you introduce flaps. Now, there are probably a few differences between the R model and what I actually flew, so take my words as a grain of salt. Given the airframe, however, I doubt there would be that much of an appreciable difference, which leads me to believe that the A2A C172 is pretty accurate in that regard.

I do find it quite easy to balloon the 172 in the sim here as well, but I think one important factor that should be considered is the fact that you cannot really feel the weight of the aircraft on some usb joystick or yoke--for obvious reasons. In this regard, flaring the aircraft would indeed feel awfully sensitive, and can easily result in a balloon if not careful.

[n421nj]

I think the issue is the controller sensitivity. It's not the real thing and will not feel like the real thing. a2a needs to expand into the hardware business and produce an official a2a force feedback yoke.