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[REPORTED] Error in Ground Effect?


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Hi I would like to report an issue with the Hornet and its interaction with the ground. I suspect a issue with ground effect. The aircraft does not demonstrate proper ground effect when flying at 20Ft AGL and the lower you get the aircraft gets sucked into the ground. The aircraft tends to get sucked into the ground rapidly regardless of control input and it gets stronger as speed increases and altitude decreases. I suspect this issue has also been the reason my take off performance seems to be fairly extended. The best way to explain this is to experience it. Grab a hornet and attempt to fly 20Ft AGL and eventually you'll get pulled into the ground. The aircraft will be sucked into the ground. I'm afraid this kills the takeoff performance as well and might be the reason for the weird habit during bolters on the carrier making it the reason it's so hard to disconnect from the ground.

 

Originally I thought this was related to the issue with the flaps bug, but now the flaps are fixed and work amazing so that tells me it's an issue all on it's own. If you can not replicate this issue please get back with me and I will submit multiple tracks demonstrating the issue. I will also have a video posted today June 19, 2018. Video link will be added later to this thread. Thanks!

 

Here is the Video Link demonstrating the issue.

reversege.trk


Edited by TheFlyingGear

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Hi I would like to report an issue with the Hornet and its interaction with the ground. I suspect a issue with ground effect. The aircraft does not demonstrate proper ground effect when flying at 20Ft AGL and the lower you get the aircraft gets sucked into the ground. The aircraft tends to get sucked into the ground rapidly regardless of control input and it gets stronger as speed increases and altitude decreases. I suspect this issue has also been the reason my take off performance seems to be fairly extended. The best way to explain this is to experience it. Grab a hornet and attempt to fly 20Ft AGL and eventually you'll get pulled into the ground. The aircraft will be sucked into the ground. I'm afraid this kills the takeoff performance as well and might be the reason for the weird habit during bolters on the carrier making it the reason it's so hard to disconnect from the ground.

 

Originally I thought this was related to the issue with the flaps bug, but now the flaps are fixed and work amazing so that tells me it's an issue all on it's own. If you can not replicate this issue please get back with me and I will submit multiple tracks demonstrating the issue. I will also have a video posted today June 19, 2018. Video link will be added later to this thread. Thanks!

 

 

Great post. I was wondering if I was imagining it.

 

 

 

I've noticed that I'll configure the aircraft for a straight-in approach from around 5 miles out and 2,000 ft, Everything's lovely and stable all the way down, until I'm just over the runway, when RoD suddenly increases. As you say, one would, if anything, expect the opposite from ground effect.

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Good thread, I thought there was something off but couldn't put my finger on it.

one would, if anything, expect the opposite from ground effect.

^

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I can corroborate this also happens to me.

 

May I remind ED that low level flight is not a stunt, from aborted landings to terrain masking, it is very important for combat as well as normal and abnormal operations.

 

Remember the DCS Hornet had (mostly still have) the flaps issue, where the drag/lift logic was somehow exaggerated and some would say inverted, so this could be fixed too.

"The natural function of the wing is to soar upwards and carry that which is heavy up to the place where dwells the race of gods.

More than any other thing that pertains to the body it partakes of the nature of the divine." — Plato, Phaedrus.

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Tried at 650 knots over the Stennis and thankfully the ship deck was behind me by the time the nose came down a bit.

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Video demonstration of ground effect Bug

 

Here is the video for the ground effect bug I made a thread about.

 

"Do not give up when you fail, but only once you succeed"

 

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Here is the video for the ground effect bug I made a thread about.

 

 

Wow, very strange. When landing on terra firma there is (or has been) the correct cushioning from GE, though I think it's a little exaggerated for the Hornets wing area. Your video certainly tells a story though, and it ain't subtle!

 

EDIT: After some testing I came to realize that there doesn’t seem to be a ground effect on normal airfield landing. Low to the ground I was adding a little power to soften descent, a ‘power flare’ I guess you could call it. Either way, the reverse ground effect is definitely there when flying lower than ~30 ft. I got sucked into the ground multiple times while testing.


Edited by SonofEil

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Great post. I was wondering if I was imagining it.

I've noticed that I'll configure the aircraft for a straight-in approach from around 5 miles out and 2,000 ft, Everything's lovely and stable all the way down, until I'm just over the runway, when RoD suddenly increases. As you say, one would, if anything, expect the opposite from ground effect.

 

I'm sorry but I have to retract this. Either something has changed in the latest update or (much more likely) it was me not controlling my throttle well enough. However, I'd add the following

 

I set up around 5 miles away from the runway at 2,000 ft to follow a 3deg glideslope. Wind is 10 knots straight down the runway. By this point, I am flaps full, gear down, on AoA and I have the fpm on the runway threshold.

 

I will get to a point where I think the fpm is settled on the threshold but it's very hard to keep it there. Minor throttle adjustments cause the fpm to keep rising or falling, sometimes it will stabilise, but it will not stay that way for long.

 

Around 450 ft agl (when the radalt goes off), the fpm starts "bouncing up and down inside the bracket".

 

 

Over the runway, I would say I don't actually notice any ground effect whatsoever.

 

I not suggesting anything's wrong or that there are bugs, but is anyone able to set up and go hands off all the way down (no turbulence)?

 

Does anyone know what the technique is for flaring the aircraft? Can you lift the nose up much higher before a tail strike?


Edited by Hippo

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  • 2 weeks later...
The aircraft does not demonstrate proper ground effect when flying at 20Ft AGL and the lower you get the aircraft gets sucked into the ground. The aircraft tends to get sucked into the ground rapidly regardless of control input and it gets stronger as speed increases and altitude decreases. I suspect this issue has also been the reason my take off performance seems to be fairly extended. The best way to explain this is to experience it. Grab a hornet and attempt to fly 20Ft AGL and eventually you'll get pulled into the ground. The aircraft will be sucked into the ground. I'm afraid this kills the takeoff performance as well and might be the reason for the weird habit during bolters on the carrier making it the reason it's so hard to disconnect from the ground.

 

Here is the Video Link demonstrating the issue.

 

Bump again. I've been trying many airfield landings lately and can confirm this behaviour. I hope we can know what ED thinks about this; whether it's what they intended or is it labeled as bug on their side?

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I noticed this just yesterday on the Blue Flag server.

I was flying very low over the sea, at around 40 ft, the airplane started to get sucked down, I had to pull very hard to keep it from hitting the water. The same thing happened every time I got below ~40 ft. Very strange.

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Wow, the test pilot spirit has awaken in me... again. I don't know how the heck I missed it so far, can't wait to do some testing tonight. I've done lots of flying in the weeds or over water at 20~40 feet and it seemed real solid... perhaps too solid. Well, I was going like a bat out of hell though. In the "FlyingGear" video the downward burble past the deck does seem scary!

 

Someone here mentioned that the take-off roll is extended. That part I could understand. When taking off from the runway the Hornet's nose has to come up early enough to lift off in optimal distance. That's why even vertical stabs are toed in when trimmed for take-off. In spite of that the stick had to be nudged back slightly before hitting 90 knots(?) If you let the nose stay down too long... there will be a pitch down moment. It has to do with the shape of Hornet's wing. (The outboard part is "twisted" down) This applies to legacy Hornets not the Rhino.

 

I'm not sure about the ground effect. There shouldn't be any perceived ground effect when touching down in the Hornet (from what I've heard or read) but no pull down! There must be some weird script... can't wait to test this myself.

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It's just not finished. Hence the 'early acces' label.

 

Yea I know, still... Thanks to some observant folks here the devs have a chance to get some feedback with newly discovered bugs that "regular" beta testers might have missed.

 

I did have a chance to test this for myself:

In dirty config. or PA mode I did not notice any pull down. I approached Batumi settled in 600 f/min descent and slowly transitioned to 100 f/min at 40 feet and was holding it of to almost 0, then I heard the wheels touching down... I set it down "on eggs".

 

Now, when cleaned up I approached Batumi again from the water at 360 kts at 40 feet, noticed the field elevation coming up so I pulled up a little just to clear the ground then as soon as I crossed the runway threshold my VV dipped. I almost augured in.

 

Again, kudos to those who notice stuff like this!:thumbup:

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This is not happening when landing, but when you fly fast and low, like 30ft AGL. Hence why I'm saying that it's not a bug, but probably more of a thing that the devs didn't get to yet.

You can try it yourself, it's very easy to reproduce. Just take your -18 and go MIL over the water or somewhere else flat enough to get really low, and see what happens when you get low enough. :)

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...You can try it yourself, it's very easy to reproduce. Just take your -18 and go MIL over the water or somewhere else flat enough to get really low, and see what happens when you get low enough. :)

 

Absolutely nothing happened:D

I was happily surfing at 30 ~ 40 feet at 500 kts and only the "betty" was unhappy and yelling at me. Only over the landing surface. (in my case at least)

 

All right I think by now everyone "knows".:smilewink:

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In dirty config. or PA mode I did not notice any pull down. [..]

I've noticed the opposite. When landing in an airfield, just below 30/20 ft, a second or so before touchdown, there is a sharp pull down that I try to resist with almost full back stick which seems to be completely ineffective. Feels like there's a magnet that pulls the nose down to the runway.

 

[..]then as soon as I crossed the runway threshold my VV dipped. I almost augured in.

For me, it's not the VV that dips as much as the nose itself that pitches down.

 

This is not happening when landing, but when you fly fast and low, like 30ft AGL. Hence why I'm saying that it's not a bug, but probably more of a thing that the devs didn't get to yet.

I have an almost 100% success rate of reproducing this while landing at airfields (where it's more noticeable than carriers). Maybe it's subtle to some folks, but try it again and pay attention to when you hear the 'thump' of the wheels touching the tarmac compared to when you began your pitch down.

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