C-177 takeoff speed and ground effect

[stinkdog]

First, I love this airplane. Having said that, it seems as though there is no such thing as ground effect at work on the plane. If it stalls at 50-some with no flaps, then it seems it should at least lift off at the same speed with the flaps down at takeoff position

I once had a Cardinal (A, not B) and it would pop off the ground at just above the bottom of the white arc and fly in ground effect. That was how I was tought to handle soft field takeoffs. I can't make this bird do that. I go screaming down the runway with the yoke full back and it won't even rotate. My real Cardinal would pull its' nose gear off almost at once due to prop blast but this one refuses to lift the nose until almost at takeoff speed - and it refuses to take off until way over 60. This strikes me as someone's bug or a configuration problem. Is there a data entry I can change to get it right? I would point out that I don't really want or need more elevator authority in flight, if anything, it could be toned down a bit. I just wonder why it won't rotate until so late and won't fly at the same speed in ground effect that it could out of it.

Jim

[jcmissionary]

I could be mistaken, but I don't believe that FS2004 models ground effect.

http://www.dreamfleet2000.com/gfx/im...RUM_HOWELL.jpg
PPL-ASEL
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[petermcleland]

Try setting a little more nose up trim before you start the roll.

[nojwod]

nose up trim remembering that the trim in FS2004 is not realistic in that it moves the authority of the elevator up or down to simulate the pressure on the yoke. This means that with the trim set to the middle of the arc the fs model won't give you full elevator effect up.

[ladamson]

With the Cardinal in FS2002 ( havn't updated for FS2004 yet), I can break ground at 56 kias with full back elevator. As far as I know, FS2002/FS2004 also doesn't model ground effect. And elevator control while still rolling on the ground isn't as good as in some prior versions. Apparently MS no longer seperates the ground & flight dynamics. Older versions (FS98 & maybe FS2K) would lift the nose rather quickly & then wallow side to side, to a stall, if you didn't watch it.

Since I heard X-Plane might model ground effect, I just tried the Cessna in that sim. The nose will lift off sooner in X-Plane, but it really doesn't model any additional forces to push the yoke against, as you'd get when building speed while flying low in ground effect.

Ladamson

[stinkdog]

Hmm... I'm really sorry to get that answer. I set the trim to the proper position for takeoff in a real airplane. If I set it so it's cranked way up, then the plane will over-rotate and be too sensitive on climb out. I have a problem with intentionally misconfiguring an airplane in a simulation or not.

OK, if ground effect is left out of the equation, the plane should still lift off at just above the stall speed for its' configuration. If ground effect were part of the lift, it should be possible to force it to fly at BELOW its' stall speed as long as it was below about 15 feet or so off the ground. Without any ground effect, if it were already in flight at just above stall speed, it would climb as it accelerated from that speed. Instead, it won't do squat until nearly 60, yet it will fly (although very poorly) at something like 46. I believe that this is more than just lack of ground effect.

Basically, I believe something is wrong beyond the known shortcomings of FS. My Cardinal actually had an AD performed on it to reduce its' elevator authority, and it still had far more than this model. Porpoising on landing if you were too fast was a well known gotcha of the bird, due to it being so powerful in pitch, as well as its' tail low stance on the ground.

Cranking the trim to get adequate authority shouldn't be necessary on an accurate model of this aircraft. I believe that the model should be adjusted to simulate the full power of the elevator without having to misconfigure the aircraft.

FWIW, it won't "really" stall either, probably for some of the same reasons, yet the real bird is a get your attention bottom-drops-out type staller. It'll shake and squeak at you and then bang, it's departed from flight and the nose drops like a stone. The model just kind of mushes down gently. I don't think I should have to look at the bottom of the screen to see if it's stalled. The real bird bites when it's mistreated. I realize they made a few aerodynamic changes from the A to the B model, but discussions with other owners led me to believe that it still was a good deal more lively in this area than most other Cessnas. Mine handled like a fighter (a really badly underpowered one).

[stinkdog]

>With the Cardinal in FS2002 ( havn't updated for FS2004
>yet), I can break ground at 56 kias with full back elevator.
>As far as I know, FS2002/FS2004 also doesn't model ground
>effect. And elevator control while still rolling on the
>ground isn't as good as in some prior versions. Apparently
>MS no longer seperates the ground & flight dynamics.

It seems that there's something more at work here. The fact that you're on the ground should be a non-issue, if they don't model ground effect. My C-177 would lift off at way below 46. I never dared to look at the airspeed just then, for some reason. Mine read in MPH, not knots, BTW.

> Older
>versions (FS98 & maybe FS2K) would lift the nose rather
>quickly & then wallow side to side, to a stall, if you
>didn't watch it.

Like the real plane. You pull the yoke back, full throttle, the nose comes up and you hold that until it just breaks ground and then VERY quickly neutralize the yoke and fly level until you build up enough speed to climb out. That's what I'm looking for.

>Since I heard X-Plane might model ground effect, I just
>tried the Cessna in that sim. The nose will lift off sooner
>in X-Plane, but it really doesn't model any additional
>forces to push the yoke against, as you'd get when building
>speed while flying low in ground effect.

Bummer.

[KenG01]

I wish there was a simulator that accurately modeled real flight characteristics -- all of them. However, none exist (including X-plane). The air files that help determine how a particular plane flies are pretty much a black box in some areas. That is, MS have not given much (if any) guidance on what those parameters do and how they affect the aircraft.

That being said, the DF aircraft (the Cardinal included) are some of the best available regarding fidelity to flight characteristics within the confines of the restrictions imposed by this simulator. Nevertheless, it falls short and that's too bad but IMO not a reflection on Dreamfleet. Instead, it points to where improvements can be made in aircraft models, clarification of air file parameters, and the core of the simulator.

In short, I feel you are expecting more from Dreamfleet's product than it was designed for. I feel you pain, as likely do all the pilots here (including Lou).

[stinkdog]

No argument about the quality from me. My remaining hair stood up when I heard the gyros spin up the first time. Same identical sound as my bird. Other than the non-stall and the refusal to lift off, it's a super simulation.

I just think that if the plane will climb under given circumstances at 1000' AGL, then it should do it at 0' AGL, and it won't. There's something odd going on while the plane is on the ground. It's almost as though ground effect WAS modeled, but MS subtracted lift rather than added it! I would NOT be shocked to find that out.

Also, it seems as though ground effect may well be present on landing. I've floated the entire length of 10L at KPDX (and clean off the end) just for being 15 knots over the correct speed in the 777. Next time around I was (identically configured) 15 knots slower and the thing plopped down and stopped in less than 1/2 the runway. As real as it gets.

[ladamson]

>Like the real plane. You pull the yoke back, full throttle,
>the nose comes up and you hold that until it just breaks
>ground and then VERY quickly neutralize the yoke and fly
>level until you build up enough speed to climb out. That's
>what I'm looking for.
>

I've been trying soft & short field takeoffs in all flight simulator brands/versions since the beginning. The visual effects would vary from burying the tail in the runway, to the tail not even going down when pulling yoke all the way back. But no real sense of ground effect in any PC sim....

But wait, I might have to go back to IL-2 Sturmovik & see if any existed there! :)

Ladamson ---- never looked at airspeed either. I guess it didn't matter!! :) Piper Archer & Cessna 207