>Here's a quick question for you: When is ground effect a>godsend?Dead stick on short final?

I would be very interested if you would name a few.Thanks,Jim

Just to be sure there was no misunderstanding, I don't think there is developer criticism here...certainly not in my posts in this thread where I stated that I believed the limitations where in the FS9 engine.Certainly, there is no criticism of RealAir since you people have produced some of the very best add-ons in the hobby including the Spitfire and the Marchetti.<>Right but as you know far better than I, there are two forces that combine to produce ground effect...chord dominated and span dominated forces. Anyone interested in the aerodynamics of ground effect can go here http://www.se-technology.com/wig/html/main...pen=aero&code=0I have yet to see a machine that exaggerates ground effect, let alone grossly.Try landing a 172 at, say, 80 kts. It just WILL NOT LAND. Oh, you can force the gear onto the runway but that is not a "landing" and it certainly will not be your ONLY "landing" resulting from that particular approach. My primary instructor used to rate EACH of my "landings" after a too fast approach!So, as the art and science of aircraft modeling continues to evolve, I would just put on my wish list...to the extent that it is possible with the FS software...to model the "flare/landing" regime such that at any speed much...if at all...above 1.3 x VSO...when the aircraft reaches the distance of half the wingspan...a swoop up of AT LEAST 10 feet would be the result and would CONTINUE to be the result when that same distance off the runway is again reached while airspeed remains in excess of 1.3 x VSO. The skilled pilot who encounters float in spite of proper approach speeds...due to gust components...will anticipate the float and NOT continue to pitch up to touchdown attitude until the seat of his pants tells him that ground effect is dissipating.Regards,Jim

1. The Wright Bros..who would never have flown the Flyer without it.2. The seaplane Dornier DO-X could only cross the Atlantic when it was flying with its hull just above the wavecrests. 3.In the second World War pilots knew that when they went "bingo fuel" on the way back from the enemy that they could reach home by flying just a few feet above the sea, thus needing less power and saving fuel.4. Howard Hughes when he "flew" the Sruce Goose.

3.In the second World War pilots knew that when they went "bingo fuel" on the way back from the enemy that they could reach home by flying just a few feet above the sea, thus needing less power and saving fuel.

I wonder how much of a savings this was compared to flying at altitude where you burned less fuel for the same TAS ?At what altitude was the fuel savings greater than the savings by Ground Effect ?:)

Yes the ground effect is modelled.If the .air file is done properly.400=*dCl/dAoA vs Relative Height - Ground Effect,tbldb400h=Varies Slope of TBL 404 due to Ground Effect|x=Altitude(AGL)/Wingspan, y=Cl Factor|Increase Y-1.0 by 20% to get sig. effectIan

<Massively better to fly in ground effect that at altitude. First, you would burn tons of fuel just climbing to the most effecient altitude so the benefits would be negligble and probably negative.Regards,Jim

Ian, would you kindly recommend which aircraft you fly that you consider well modeled for ground effect?THANKS!Jim

Guys there are even airplanes that only fly with ground effect!You probably haven't seen it the russians have done alot of testing with such vehicles. The wanted to use them as ultra highspeed trouptransporters.Here's a little video from one very impressive model!http://www.n.ethz.ch/student/clgraf/videos/km01.avicheers,Claudio

Sorry for my bad english! Here a corrected version:Guys there are even airplanes that only fly with ground effect!You probably haven't seen it, but the russians have done alot of testing with such vehicles. They intended to use them as ultra highspeed troop transporters for the black sea region.cheers,Claudio

Hi All, Interesting discussion - the use of ground effect was most useful to the WWII pilots and crews when returning shot up or with mechanical problems. (But no doubt when short of fuel also)When an aircraft was unable to maintain height and slowly sank towards that deep dark North sea, whilst trying to make the English coast, some, to their surprise no doubt, found that their slow descent was arrested as they closed the waves of the sea. Thus managing to just scrape home. The ground effect being just enough to compliment their failing engines/lifting surfaces. Many, many more were not so lucky unfortunately, but a "godsend" if you were one of the lucky ones!I know nothing of computer modeling (except to enjoy the wonderful creations of those that do:-0 ) however I suspect that the constantly varying "lift" and "sink" effects felt in the real world would be jolly difficult to replicate. (Their cause being many and varied - differing temperatures of varying surfaces, wind/slope/sun/shade etc.etc. etc.) These effects have a great deal to do with the constant adjustments pilots make during an approach and landing and can even catch out very experienced pilots. Regards, Blue.

As pointed out by av84fun above, the original Wright Flyer is an example of one that requires the ground effect. To see this, try to gain some altitude in it after takeoff.

Jim,one comment .. Microsoft could exlikely model the Real World landing process and allow the true fans to use one level of realisim while those who do not desire this can tone down the realism ... that would stem any complaints ...Vernon

>Try landing a 172 at, say, 80 kts. It just WILL NOT LAND. Oh,>you can force the gear onto the runway but that is not a>"landing" and it certainly will not be your ONLY "landing">resulting from that particular approach. My primary instructor>used to rate EACH of my "landings" after a too fast approach!>Actually, the default 172 won't land at 80 kias either. Unless of course you force it down with elevator, or use trim to force down elevator.Farther up the list you said: >"In fact, the modeling of the entire landing event is unrealistic in >most cases in that you can just "drive it on" with virtually no >flare and get a "chirp and stick" landing (i.e. no bounce)."For me, landing is one of the greatest pleasures I get from FS9. Some models are without doubt better than others, but the sensation of rounding out, flaring, and holding it slightly off the runway as airspeed bleeds off, and the yoke or stick is pulled nearly all the way back is excellent. IMO, a good VC and rudder pedals for this "exercise" is a must.L.Adamson

Donny AKA Shalomar Fly 2 ROCKS!!!Ground effect was DEFINITELY a godsend when I was about 22 taking real world flight lessons. I went up with a different instructor than my usual who shall remain useless. (I meant to type "nameless" but I'll leave it that way.) The first thing he aked me to do after takeoff and cruise to the training area using 15 degree bank turns was a 45 degree bank turn which I had never done before. We were at 800 feet which made me nervous about a steep turn. I asked if I could do a 30 degree bank turn or two as a warmup. He refused. My first few turns were sloppy. He told me I was concentrating too much on the instruments. He covered them up and said to keep the third rivet on the nose to the horizon. My turns improved so he uncovered the instruments. We took turns doing 45 degree turns. We were in VFR conditions but about 1/3 of the horizon was obscurred. As fate would have it on the last turn I made we were headed toward that portion of the sky. I lined up the nose on a descending ridgeline. I heard my instructor say "45 degrees". I glanced too quickly at the artificial horizon and saw it was right on a mark. Based on what I saw out the windsheild I assumed I was only at 30 dgrees so I STEEPENED the bank past 60 degrees. My first indication of trouble was an increase in engine noise. I glanced at the panel. About 45 minutes of thought passed thru my mind in the next few seconds. I saw the gyro at 80 degrees and VSI at two thousand. Based on the rate of change I am sure we went knifeedge and pegged the VSI, it didn't slow down a bit when going past 1500 so our rate of descent was increasing exponentially. We were far past the point where a good CFI intervenes. At this point I nuetralised the controls expecting my companion to become a good CFI. I looked away from the panel towards the ground and remembering our initial altitude started doing mental math based on what I had seen on the VSI. I looked at my companian noticing a vacant look and no movement of hands to the controls. Suddenly I realised that if I didn't do something very soon not even a CFI could complete a recovery from where we would be. At that point a barn was rapidly increasing in size. At that point my hands convulsed on the controls and I uttered the classic phrase, "ShxT!!! We're going in!!!" My hand had inadvertantly trigered the mike button on the yoke. I wasn't wearing a headset but the mike hanging from the panel picked it up. "POSITION???" was the urgent response. My companion grabbed the mike, not the controls. "Lake Noxamixon." said he. "CESSNA 409" we shouted together. "I'll send equipment." Two thoughts passed thru my mind. "I just sent a false mayday" and "what good will an ambulance/fire truck do me after I scatter this plane over half an acre?" I yelled "NOT YET, STAND BY." I hadn't really ever expected to die, I just knew I had to do something when I saw my companion wasn't. I remembered a letter to the editor I had read in Flying mag about proper recovery from a spiral dive. Unfortunately I forgot the first step of "reduce power" and went right to levelling the wings. The controls were HEAVY. when they lightened I sensed we must be near level bank and commenced pulling back. I knew the acedemics of accelerated stall and how much control throw a C 150 yoke had so I pulled back about 3 inches and held it there. To my surprise the pressure required to hold the yoke there increased and increased and increased. It got to the point where I did not have enough strength to hold it so I scrunched down and let the increased weight of my arms help me out. I could no longer keep my head from ny chest and soon after everything went black for what seemed like an eternity. Eventually the G's lessened and I looked up to see we were at five degrees bank and the nose was five degrees above the horizon. To my horror I realised our rate of descent was still phenomenal and I dared not pull the nose up any more. I then remembered something I read in Yeager's biography about trying and failing to fly the Aircobra into the ground at high speed due to ground effect. I knew the best ground effect was zero pitch and bank. I saw two options. The first was to continue at our bank a little while longer and ride it to a depression in the ground. But the end of the depression was steep. The second option was to go to zero bank almost right away which would result in a vector over a level highway. I remembered hearing ground effect occured 1/3 the span of the wing at near stall speed. I guessed we would be in ground effect at least half a span high. Span on type was 28 feet= aproximately 13. I saw no trucks or buses so I knew we would be safe if Yeager was right. The thought of killing people on the ground never occured to me, I agree with Yeager about stories of pilots stearing doomed aircraft away from schoolyards is TOTAL B.S.. I leveled the wings and went to zero pitch. Pushing the yoke forward took all the willpower I had as we PLUMMETED toward the highway. I noticed that traffic was stopped behind a state cruiser. I saw my impact point at about the fifth row of cars but held firm to my plan. As I got closer suddenly I recognised the trooper as a personal friend. Our eyes met. I didn't need two hands to keep controls nuetral so I waved at him. NO LIE. At this point thre was NOTHING I COULD do and an erie peace had settled on me. My friend hunkered down behind his car door but not before I saw I wrecked his hairdo. The fact I could see the effect of our bow wave gave me hope. Shortly thereafter all forces on the yoke ceased. My first thought was the tail had snapped off but then I realised my plan had worked, we were skimming the highway in ground effect. It seemed like a giant hand had just positioned itself under us. I saw the windsheild wipers rise on a LOT of cars. I was still afraid of accelerated stall and felt safe at our new descent rate of zero so I hesitated to climb. The wings rocked gently reacting to the shapes of cars as the DRAG of the fixed prop slowed us down. We were still at cruise setting. I passed over a very cute blonde with blue eyes in a white Mustang convertible with blue suede interior. I pushed the yoke forward to keep her in view longer. (Actually I was looking for a ring.) When I saw her expression change to horror I regretted lingering over the highway. I pulled the yoke back three inches. I didn't feel any G's. I looked up at only blue skies. A sense of relief flooded over me. Then I wondered about a conventional stall. I wanted to push the yoke forward but my muscles would not obey. I tried to check airspeed but could not move my head or my eyes. I was a zombie. My companian metamorphosed back to a CFI and pushed the nose down. "You don't want to crack the ARSA." I was able to look at the altimeter and radio "SAFE AND SOUND AT 400 AGL." Actually we were at 1400. The girl at the FBO desk broke in, "You had me worried." I said something then she said something I can't remember. I said "If I had thought that ten seconds ago I'd be dead." She said, "Ten SECONDS? It seemed like ten MINUTES." My reply? "I love you too." I loved everybody in the world right then. My instructor told me privately, "I never intervene above 400 AGL." Then he said "Shxt", grabbed the mike and announced, "I just committed the CARDINAL sin. I froze and a student had to bail me out. Cessna 409 EMERGENCY MAJOR STRUCTURAL DAMAGE." After we landed the plane was declared by Cessma engineers to be the most severely damaged and land safely. My instructor changed his story and said it was my fault, I had attemted a loop. The trooper was forced to reveal the identity of the pilot and it came down to a recorded deposition. My version of the story matched radio tapes slightly better than his. It was a major bullet to duck, the FAA can fine you or take your license which I didn't have but the state WILL put you in jail. Sorry for the long post, maybe some will find it interesting. BTW our altimeter had been set to read zero just before takeoff. Queen City airport elevation is about three hundred feet. Had the altimeter been set to read elevation this story would probably have a different ending.