The use of ground effect.

[SToL]

But maybe we’re just being pedantic.

Probably.

Generally, I think of things that cause or contribute to an accident as more or less 'bad' things, or at least 'not ideal' things. Such as, high altitudes, HDA, high temps, humidity, weight, tailwinds, people with low time, less experience, cranialanal impactions, etc.. those are not good things for aviation.

Ground effect is good for aviation. You're turning ground effect into a bad thing because the pilot made *several* mistakes.

Was it the ground effect itself that contributed, or the pilot’s inability to recognize the consequences of ground effect. A distinction without a difference?

I believe there is a distinction. The pilots decision to depart ground effect prematurely is what contributed. That's why we learn and study performance charts, v speeds etc... If you're going to go flying, it's your responsibility to understand how all of these things effect the ac you're flying. Otherwise you're just a test pilot and anything goes.

But as you said... it's just our opinions. There's truth to both views.

PJ

 

[SToL]

Have you considered how hover-craft aerodynamics relate to fixed-wing aerodynamics?

I think a better observation would be something similar to this...

Russian Top Secret Aircraft - YouTube

 

[luvflyin]

I think I disagree.

In a world without ground effect, the plane never would have gotten airborne in the first place, allowing the pilot the option of stopping on the runway. It was ground effect that set the stage. Hence it “contributed”.

But maybe we’re just being pedantic. Was it the ground effect itself that contributed, or the pilot’s inability to recognize the consequences of ground effect. A distinction without a difference?

I can't think of too many, if any, NTSB accident reports where something like this was put in the Preliminary Narrative, it's the last paragraph. "The Federal Aviation Administration (FAA) Airplane Flying Handbook (FAA-H-8083-3A) noted that ground effect is a condition of improved performance encountered when the airplane is operating very close to the ground. Due to the reduced drag in ground effect, the airplane may seem to be able to take off below the recommended airspeed. However, as the airplane rises out of ground effect with an insufficient airspeed, initial climb performance may prove to be marginal because of the increased drag. Under conditions of high-density altitude, high temperature, and/or maximum gross weight, the airplane may be able to become airborne at an insufficient airspeed, but unable to climb out of ground effect. Consequently, the airplane may not be able to clear obstructions, or may settle back on the runway." The NTSB felt it significant enough to talk about in the Preliminary and get it out there. The final Probable cause was "The pilot’s inadequate preflight planning, which resulted in his attempt to takeoff in conditions under which the airplane was unable to attain a positive rate of climb and resulted in its failure to clear trees." They didn't name 'ground effect' as a cause, that was pilot error. And like so many, the error occurred before the plane took off. If I was in charge, ground effect would have it's certificate suspended and undergo remedial training.

 

[SToL]

If I was in charge, ground effect would have it's certificate suspended and undergo remedial training.

I just spit some of my coffee out. Thanks for that.

 

[SToL]

I'd submit that this "Russian Top Secret Aircraft" represents a very high-powered, high wing-loaded fling boat that is unable to sustain flight below a certain airspeed

Or above a certain altitude I presume. Anyway, I posted that to the wrong person, It was not intended for you, for I know nothing of hover craft aerodynamics. I'm not even sure they're real.

PJ

 

[Juliet Hotel]

Oy vey I've gone and touched off a sh*t storm. I don't think that was my intention but I take full responsibility none the less. This thread has been informative for me (hopefully a few others too) and it has really made me rethink my position on this.

And upon reflection and consideration of what has been presented in this thread I'm happy to report my core position has not changed.

Ah only kidding. It has changed a bit. Not a lot, but a bit.

I think most who read what I wrote would take it to mean I believed ground effect did not exist. But this thread has made me realize that is incorrect, it clearly does exist and clearly can be demonstrated.

I'm still not buying that ground effect is what screws up so many landings for so many student pilots as CFI's so often tend to claim. I think the 'oh you forgot about ground effect...' excuse is mostly used as a tool for CFI's to keep students from getting so frustrated with their lack of ability that they give up and stop taking lessons. It ain't ground effect that's screwing up their students landings, its their students that's screwing up their student's landings.

I also don't buy the 'hey look at all this free performance from ground effect claims in video clips of a 200+hp plane nosed over above a runway at full throttle. Yeah its ground effect that's doing that for you and all that horsepower and all that fuel burn had nothing to do with it

So color me corrected, ground effect does indeed exist. But also color me skeptical, ground effect does not contribute nearly as much to performance as many people claim it does.

Apologies for the sh*t storm. Many thanks for the thoughtful responses.

 

[motoadve]

Contrary to what I would have expected, the Cessna being high wing, when in ground effect and when gaining speed its harder to keep low to the ground , and wants to lift on its own and I need to push harder on the yoke than in the CJ6 which is a low wing.

 

[luvflyin]

Oy vey I've gone and touched off a sh*t storm. I don't think that was my intention but I take full responsibility none the less. This thread has been informative for me (hopefully a few others too) and it has really made me rethink my position on this.

And upon reflection and consideration of what has been presented in this thread I'm happy to report my core position has not changed.

Ah only kidding. It has changed a bit. Not a lot, but a bit.

I think most who read what I wrote would take it to mean I believed ground effect did not exist. But this thread has made me realize that is incorrect, it clearly does exist and clearly can be demonstrated.

I'm still not buying that ground effect is what screws up so many landings for so many student pilots as CFI's so often tend to claim. I think the 'oh you forgot about ground effect...' excuse is mostly used as a tool for CFI's to keep students from getting so frustrated with their lack of ability that they give up and stop taking lessons. It ain't ground effect that's screwing up their students landings, its their students that's screwing up their student's landings.

I also don't buy the 'hey look at all this free performance from ground effect claims in video clips of a 200+hp plane nosed over above a runway at full throttle. Yeah its ground effect that's doing that for you and all that horsepower and all that fuel burn had nothing to do with it

So color me corrected, ground effect does indeed exist. But also color me skeptical, ground effect does not contribute nearly as much to performance as many people claim it does.

Apologies for the sh*t storm. Many thanks for the thoughtful responses.

sh*t storms keep this place alive. Thanks for checkin back in

 

[Dan Thomas]

Contrary to what I would have expected, the Cessna being high wing, when in ground effect and when gaining speed its harder to keep low to the ground , and wants to lift on its own and I need to push harder on the yoke than in the CJ6 which is a low wing.

That's a trim issue. With flaps extended the Cessna has a strong pitch- up tendency. Setting the trim in the usual spot won't work.