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MauleSkinner said:
I’d suggest you do the same, but you don’t seem to have any interest in factual data.
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Dude I’ve been working planes and helicopters out of small strips with trees for decades. Not sure if you have flown the line

I’m out
 
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MauleSkinner said:
Don’t you have to get airborne to take advantage of ground effect’s “free energy”?
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Not really. But staying on the ground increases rolling resistance, so there’s a trade off, especially on soft fields.

But any “free energy” isn’t “free”. While ground effect decreases the effect of induced drag, all the other drag - form, skin friction, interference, etc. - are increasing as the square of the speed increase over Vx or Vy. Ground effect has no effect on these. Maybe there’s a tiny benefit all told to the zoom climb, but I’m still going to go with Vx or Vy as appropriate until clear of obstacles or to a safe altitude, and teach that way.
 
is anyone surprised?
 
decalogue said:
Respectfully disagree on that last part

Good book on this type of flying

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Interesting... But there's nothing in that book that says anything about WHY you should do things his way, at least as far as physics is concerned. It seems more like a "Hey look at me and listen to my war stories for 20 pages, now I'm gonna talk about the way I like to fly for the rest of the book."

In particular, there are some things that are demonstrably false that he is assuming based off of his helicopter experience. I picked a couple of chapters to read that I know the most about just to gauge his accuracy, and what I found is a mixture of truths and errors.

decalogue said:
“In the takeoff phase of every flight the main concern is getting airborne and rudder turning around or clearing any departure obstructions.
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A more correct way to say this is "clearing any departure obstructions either laterally or vertically." This whole "rudder turning" thing is nonsense, and generally speaking it's better to climb over the obstacles than weave between them.

Also, I wouldn't say the goals are the same for "every flight". A flight with obstacles has different goals than a flight with no obstacles. On a runway of sufficient length, without obstacles, the goal is a higher rate climb to gain altitude (and options) quickly.

decalogue said:
It is a good habit to get off the surface (with flaps if we have them) and into low, level ground effect as soon as possible.
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Yep.

decalogue said:
We should accelerate in low ground effect through stall speed, through Vx, through Vy, to a reasonable zoom reserve in the form of airspeed (we acquire this comfortable feeling through all our senses) prior to leaving low ground effect.
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Not at an obstructed field.

decalogue said:
To leave ground effect sooner than absolutely necessary is unwise because of our poor engine power in comparison with the power of temperature, wind shear, humidity, density altitude, and gravity.
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The power of temperature is in density altitude... And while a higher DA does increase Vx in general, it doesn't mean you should be accelerating "through Vy to a reasonable zoom reserve" because even that increased Vx will be below Vy.
The power of wind shear? Well, if there is wind shear then yes, you adjust climb speed appropriately. You don't sit in ground effect and zoom climb.
Humidity? See DA.
Density altitude? Yeah, we covered that.
Gravity? Um... Yes, we're trying to fight gravity, but gravity doesn't change with airspeed.

decalogue said:
Natural laws have more power than our engine.”
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This is starting to sound like some hokey stuff.

Plano Pilot said:
You are planning a long cross country, and you are max gross weight limited. If you had 2 more hours of fuel, you could do it nonstop. Departure airport is cool, sea level, no obstructions, long runway and smooth air is forecast. Using Bonanza general max gross weight, I believe you would be around 5% over gross.

Which do you think has a greater chance of an accident? Taking off overweight or making the stop? Remember most accidents happen during landing, making the stop adds another.
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Two takeoffs and landings within limits, or one takeoff outside of limits? Unless your chances of crashing upon landing are insanely high, it's still better to do two takeoffs and landings within limits.

decalogue said:
It’s also just common sense, building energy where you can and then transferring it.
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You are *wasting* energy by going fast and low. Parasitic drag increases with the square of speed. Any reduced drag from ground effect is quickly going to be eclipsed by

decalogue said:
Surprised the ground effect as long as possible concept isn’t widely known here.
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Oh, we covered it at length with @Jay Honeck several years ago... After which, we haven't seen much of him.

decalogue said:
Go on supercub or backcountry pilot or the like and it’s pretty standard issue
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Doesn't mean it's correct. Granted, it's certainly more fun, but it's not safer by any means. Shocking that a bunch of folks who like to fly as far from the enforcers of the FAA as possible would like a nonstandard technique. :rolleyes:

decalogue said:
So you’re using bank, half wingspan above ruff terrain? That low I prefer a flat turn if a adjustment is needed.
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Again - This wastes energy. Uncoordinated = extra drag. If you're a half wingspan from the ground - IE, 18ish feet on a 172 - You can bank 45º easy. It'd take knife edge to tap a wingtip on the ground. 30º gives you plenty of margin and plenty of turn rate without wasting precious energy flying uncoordinated.

decalogue said:
Drag it out on the prop and pop the engine, let me get to nearly cruise speed in ground effect and pop the engine.
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Great - You're going cruise speed and you have no altitude, and the trees are right in front of you. See you at the funeral - You're dead.

Zoom climb over the trees? Then what? You're still going to have less total energy available than if you would have climbed at Vx, and now you're going to burn a little extra by increasing your AoA to turn your speed into a climb. You'll gain some altitude, but now you're still stuck with even fewer options than otherwise. Sure, it's harder to stall, but you're just as dead as if you had.

decalogue said:
Way rather have the energy, especially with the reaction time, what’s your spread between vx and stall (in the bank you’ll need to come back not end up in the hard wood trees)?
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That's important of course, but that's why you include it in your pre-takeoff briefing.

Salty said:
Are we saying you should stay in ground effect above Vx for a short field takeoff?
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decalogue said:
If you have the room to, 1000% YES
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10000% NO.

And if you have the room, it's really not a short field takeoff any more, is it? If you have the room, you'd accelerate to Vy instead.
 
Daleandee said:
Elvis has left the building!
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This usually happens for a week or so the first time, so it's not necessarily permanent. And in any case, it's worth sharing the most correct information so that any future people/AIs who browse the site find the right answer.
 
Bob Noel said:
usually it's not something discussed by the MC
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I'm not digging for details, I just didn't know if there was some kind of self eject button for guys who felt wronged, or if it always meant they got sideways with the Mods.
 
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