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Excessive ground effect on landing

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Anyone else having issues with the jet floating FAR too much on landing, especially in a stiff headwind?


Bob Scott | AVSIM Forums Administrator | AVSIM Board of Directors
ATP Gulfstream II-III-IV-V

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Which version are you running? It was either hf3 or 4 that adjusted it a bit to provide a more realistic flare attitude.


Kenneth Weir

My Saitek yoke mod

 

i7 2600k @ 4.7

8GB Gskill CAS7

2x GTX580 SLI Surround + GT520 Accessory

Win7x64

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Hotfix 4 (2987). I looked in the .air file and table 400 has ground effect providing as much as 25% lift augmentation...I think r/w figures are something more like 8-10%, and probably a bit less still in an acft with winglets.


Bob Scott | AVSIM Forums Administrator | AVSIM Board of Directors
ATP Gulfstream II-III-IV-V

System: i9-10900K @ 5.2GHz on custom water loop, ASUS Maximus XII Hero, 32GB GSkill 3600MHz CAS15, EVGA RTX3090 XC3 Ultra
Samsung 55" JS8500 4K TV@30Hz,
3x NVME 2x SATA Samsung SSD, EVGA 1KW PSU, 1Gbps internet
SoundBlaster XFi Titanium, TOSLINK to Yamaha RX-V467 HT Rcvr, Polk/Klipsch 6" bookshelf spkrs, Polk 12" subwoofer, 12.9" iPad Pro
PFC yoke/throttle quad/pedals with custom Hall sensors, Coolermaster HAF932 case, Stream Deck XL button box

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Hotfix 4 (2987). I looked in the .air file and table 400 has ground effect providing as much as 25% lift augmentation...I think r/w figures are something more like 8-10%, and probably a bit less still in an acft with winglets.
Based on what information?

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Based on what information?
Roskam and Lan, Airplane Aerodynamics and Performance, Ch 10.2.1

Bob Scott | AVSIM Forums Administrator | AVSIM Board of Directors
ATP Gulfstream II-III-IV-V

System: i9-10900K @ 5.2GHz on custom water loop, ASUS Maximus XII Hero, 32GB GSkill 3600MHz CAS15, EVGA RTX3090 XC3 Ultra
Samsung 55" JS8500 4K TV@30Hz,
3x NVME 2x SATA Samsung SSD, EVGA 1KW PSU, 1Gbps internet
SoundBlaster XFi Titanium, TOSLINK to Yamaha RX-V467 HT Rcvr, Polk/Klipsch 6" bookshelf spkrs, Polk 12" subwoofer, 12.9" iPad Pro
PFC yoke/throttle quad/pedals with custom Hall sensors, Coolermaster HAF932 case, Stream Deck XL button box

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Hi Bob. how are you?. I had all your airfiles from the PSS Airbus. Great info you provided and enjoyed that old days....The HF 4 seemed to have solved the ground effect, but the developers said that they were looking at it, because discovered in the simulator (real) that the speed on finals, was not correct or that´s what i understood from Captain Randazzo.We´ll have to wait for SP1.Best regards.Miquel Egea.

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I have not noticed any problems since the relase of Hot Fix 4. I can flare at 4 to 5 degrees easily without floating. Maybe your coming in a little too hot?VREF +5 +Half the Wind +All the Gust. (If you have the Short Field Package option enabled then forget the +5 part)


Paul Deemer

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Hi Bob. how are you?. I had all your airfiles from the PSS Airbus. Great info you provided and enjoyed that old days....The HF 4 seemed to have solved the ground effect, but the developers said that they were looking at it, because discovered in the simulator (real) that the speed on finals, was not correct or that´s what i understood from Captain Randazzo.We´ll have to wait for SP1.Best regards.Miquel Egea.
Hi Miquel; Hmmmm...I'm still floating horribly with the 2987 hotfix installed...I found it very bad yesterday landing in strong headwinds. I had not seen that PMDG was already working it...thanks for the info. @Paul--it floats with threshold crossing at Vref and no additives...can't imagine what adding another 15-20 KIAS would look like!!

Bob Scott | AVSIM Forums Administrator | AVSIM Board of Directors
ATP Gulfstream II-III-IV-V

System: i9-10900K @ 5.2GHz on custom water loop, ASUS Maximus XII Hero, 32GB GSkill 3600MHz CAS15, EVGA RTX3090 XC3 Ultra
Samsung 55" JS8500 4K TV@30Hz,
3x NVME 2x SATA Samsung SSD, EVGA 1KW PSU, 1Gbps internet
SoundBlaster XFi Titanium, TOSLINK to Yamaha RX-V467 HT Rcvr, Polk/Klipsch 6" bookshelf spkrs, Polk 12" subwoofer, 12.9" iPad Pro
PFC yoke/throttle quad/pedals with custom Hall sensors, Coolermaster HAF932 case, Stream Deck XL button box

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@Paul--it floats with threshold crossing at Vref and no additives...can't imagine what adding another 15-20 KIAS would look like!!
Does any of the below help you? Although they made some tweaks in Hotfix 4 for the Flare, I still think the bird is 10 knots too fast. Look at some of the examples below. I never seen the NGX go lower than 138 on vref and they are talking about vref in the 120s. So i just treat it like its 10 knots too fast and compensate as needed.Try this and see how it works for you. Next time you are landing do everything normally with VREF +5 +Half the Wind + All the gust, but pull the throtttles back to idle sooner than you normally do so that you touch down at 10 knots slower than VREF +5. Works just fine for me and some of my flares look just like the real world videos I have seen on youtube of 737-800 landings.
*When using autothrottle to touchdown set the command speed bug to Vref +5.*When planning to disconnect the autothrottle at any stage prior to touchdown, set the command speed bug as per the following.1. Add 1/2 the steady headwind component + all of the gust to Vref (maximum Vref +20) set that speed.2. The minimum speed to be set on the command speed bug is Vref +53. The maximum speed to be set on the command speed bug is Vref +204. The steady headwind additive should be bleed off just prior to touchdown. 5.The gust additive should be maintained to touchdown Examples - 1. Vref 120kts, Runway 18, wind 180/10. Bug set at 125, touchdown at 125 2. Vref 120kts, Rwy 18, wind 180/20G30. Bug set at 140 (steady headwind = 20, 1/2 of 20 = 10. Gust = 10, so 10 + 10 = additive 20), touchdown at 130 (bleed off the steady headwind additive of 10kts & just carry the gust additive of 10kts to touchdown).There are examples given in the table above the section of the FCTM that you quoted. In a lot of situations you will be touching down below the bugged speed. This is normal. However, you shouldn't be touching down below Vref +5. You also shouldn't be flying an approach above the bugged speed or touching down above Vref + the gust additive.

Paul Deemer

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Ground effect is over the top imo. Before I get bashed, I'm not a real pilot, all I am basing it on is many video's ive watched online and experince with other aircraft. I done a test where you "pretend" to land at 1000ft mark, the difference in how the aircraft behaves when you pitch back slightly at 1020ft and cut the throttles compared to 20ft and cut throttles is amazing, i can cut throttles at 1020ft, pitch back to 5 degrees and the aircarft still descends, if you pitch back to 2 degrees at 20ft, the airaft climbs back up before descending again. It just seems fat to exagerated, a bit like flying a vstol. Even with the latest patch, I need to fly at vref -5 and cut the throttles at 100ft to get some sort of feeling to land, if I fly "on the numbers" I can simply cut the throttles and the ground effect over flares the aircraft for me without any yoke input!


-Iain Watson-

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Guys, not to trivialise your opinions (they're valid, the NGX is a floaty beast) but as we all know PMDG put a lot of work into every aspect of this sim, flight model included. Is it not possible that our technique is what's at fault here?It took me quite a while to get the hang of landing the 737 but in fairness I (and indeed all of us) have been flying heavies for years and the characteristics of those aircraft are quite different in the flare. I took the MD11 for a flight the other day, the first time since NGX beta started, and I fair SMASHED it into the ground because I delayed the flare until 20 feet!Just like the real world, every aircraft type behaves differently, it's down to you as PIC to refine your technique for the aircraft.


Mark Adeane - NZWN
Boeing777_Banner_BetaTeam.jpg

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Hi Mark. Yesterday I had a landing with a 25-kt headwind, crossed the threshold at 50 ft and Vref with the power at idle, and it floated over 4000 feet down the runway before I forced it down and planted it. I can't explain that away as technique...


Bob Scott | AVSIM Forums Administrator | AVSIM Board of Directors
ATP Gulfstream II-III-IV-V

System: i9-10900K @ 5.2GHz on custom water loop, ASUS Maximus XII Hero, 32GB GSkill 3600MHz CAS15, EVGA RTX3090 XC3 Ultra
Samsung 55" JS8500 4K TV@30Hz,
3x NVME 2x SATA Samsung SSD, EVGA 1KW PSU, 1Gbps internet
SoundBlaster XFi Titanium, TOSLINK to Yamaha RX-V467 HT Rcvr, Polk/Klipsch 6" bookshelf spkrs, Polk 12" subwoofer, 12.9" iPad Pro
PFC yoke/throttle quad/pedals with custom Hall sensors, Coolermaster HAF932 case, Stream Deck XL button box

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G'day Bob, to be fair it might be that PMDG are adjusting this parameter for the SP, I'm not sure. I'm certainly not about to tell someone with your RW experience that they are at fault!The point I'm trying to make (more for the benefit of the exclusively virtual aviators on here) is that if you try and flare the NGX exactly as you would an MD11 or 747 then you'll run into trouble.


Mark Adeane - NZWN
Boeing777_Banner_BetaTeam.jpg

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Same as Bob here, tried to land this morning with a 20 kt headwind, crossed threshold at 50ft, Vref+5, idle, floated over 3/4 of runway 11 in Oslo. Decided to go around...Haven't noticed this if no headwind is present though.Guillaume


Guillaume Estegassy

KSEA

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