In the experimental Savannah aircraft Yahoo discussion group, a fellow was advocating landing with significant amounts of power so that a a very low landing speed could be achieved. While I can see how operating behind the knee of the power curve will lower landing speed, it seems to me that this would leave you with no option but a very hard landing if the engine failed. It sort of reminds me of the "dead man" h-v curve for helicopters, where there is not enough height or airspeed to establish autorotation with an engine failure.

In a helicopter I guess you pretty much have to take that risk on take off for a few seconds while you build airspeed or altitude, but in an airplane you can avoid this altogether.

So my question to you experienced pilots out there: do you use this technique? Ever? Just for really short strips? Short landing contests?

tom

Savannah-Tom wrote:a fellow was advocating landing with significant amounts of power so that a a very low landing speed could be achieved. While I can see how operating behind the knee of the power curve will lower landing speed, So my question to you experienced pilots out there: do you use this technique? Ever? Just for really short strips? Short landing contests?

If you want to play where it's really short or really rough, or for whatever reason want wheels touching with minimum forward and/or vertical speed, then operating in ground effect with throttle acting as your elevator is a skill that must be mastered.

F. E. Potts' Guide to Bush Flying, www.fepco.com, is probably the best written description of the hows and whys of the techniques I've seen.

For me, it seems my whole flying life was heavy airplanes into shit strips, and flaring with power and easing the poor landing gear onto the ground. It's the norm for me, and a very comfortable place to be.

I'm talking about 50% or more power. Is that what you have been doing?

IF so, what contingencies do you have?

thanks,
tom

Savannah-Tom wrote:I'm talking about 50% or more power. Is that what you have been doing?

I guess the simple answer is, "It depends."

The three most important things to lock in on any landing, especially when operating on the back side of the power curve, are airspeed, airspeed, and airspeed.

Depending on temps, winds, load, type of airplane, sometimes all it takes is a finger or two of throttle once you feel ground effect and pull back on the elevator to slow the airspeed/groundspeed down to where you want it and you can fly all day. Other days it takes full throttle and getting out to push to keep from ending up a smoldering pile of aluminum when the bottom unexpectedly falls out from underneath you.

But, that gets back to stable airspeeds and experience.

Gump

Operating behind the power curve. I have probably done it but I am not sure what a good explanation for that term is. Kind of like hot roders talking about torque but have no idea of its definition.

Tim

qmdv wrote:Operating behind the power curve. I have probably done it but I am not sure what a good explanation for that term is. Kind of like hot roders talking about torque but have no idea of its definition.

Tim

"Behind the Power Curve" is the portion of the airspeed/power graph where the aircraft is on the slow side of the minimum drag point. From this point downward, drag is increasing and therefore more and more power is required to maintain level flight.

This area of flight is characterized by needing less power to go faster, hence the name. It is also airspeed unstable. That is, if something disturbs a steady state to slow the aircraft down a bit, the need for more power is increased and the plane slows even more. As you can see, the pilot work load is increased to just maintain airspeed.

tom

GumpAir wrote:
Other days it takes full throttle and getting out to push to keep from ending up a smoldering pile of aluminum when the bottom unexpectedly falls out from underneath you.

But, that gets back to stable airspeeds and experience.

Gump

And here in Nevada that falls out more often than not.

Go out at a safe altitude slow down pull the nose up where you don't feel comfortable.

Add enough power to keep flying. Once you get that mastered you will be on your way.

It seems like normal to me, I like stabilizing myself with power.

Many instructors criticize the method and want every landing to be power off.

I would rather do hundreds of landings power on an stabilized, than flop around waiting for the day the engine quits.

And like Gump says some days it takes full throttle, I have wished the throttle went past full, a couple times

Correct me if I'm wrong, but in extreme cases, and high pitch and/or angle of attack with a fair amount of power, the thrust vector is providing some of the lift, decreasing wing load factor and lowering the stall speed, enabling a slower approach.

mr scout wrote:Many instructors criticize the method and want every landing to be power off.

That's why baby CFI's and I don't get along real well. Completely different ball game flogging around in a lightly loaded C150 on a nice day and on a long paved runway, than it is working your way into short and muddy at/over gross, with shit visibility and a howling wind. You don't do power-off, glide it in from the downwind out in the real world. If I thought my engine was gonna quit at any moment, I'd take the damn thing to my mechanic and have him fix the thing.

Gump

zane wrote:Correct me if I'm wrong, but in extreme cases, and high pitch and/or angle of attack with a fair amount of power, the thrust vector is providing some of the lift, decreasing wing load factor and lowering the stall speed, enabling a slower approach.

Remember... We're talking about operations in ground effect here. Whole different look and feel than slow flight at altitude more than a wing-span or so above the ground.

Gump

GumpAir wrote:

zane wrote:Correct me if I'm wrong, but in extreme cases, and high pitch and/or angle of attack with a fair amount of power, the thrust vector is providing some of the lift, decreasing wing load factor and lowering the stall speed, enabling a slower approach.

Remember... We're talking about operations in ground effect here. Whole different look and feel than slow flight at altitude more than a wing-span or so above the ground.

So induced drag is decreased...requires even less power, and any excess airspeed above stall speed is going to burn up runway.

Are we talking about operating in ground effect here? From the OP I was thinking a steep, short approach, which depending on the limiting terrain or trees that make the short approach necessary, might be well above ground effect .

I see the need to keep the airspeed to a minimum though, so that when you do enter ground effect and chop the power, there absolutely zero excess airspeed to bleed off, and you are the on the ground and done flying.

Great thread.

There was a recent thread on supercub.org about steep takeoff climbs with flaps, and how in the event of an engine failure, there is simply not enough airspeed to continue flying power-off, no matter how hard you push....obviously catastrophic.

Sometimes behind the power curve is meant to be the point to where you are comitted. I.E. you don't have enough power to go around, your landing one way or the other.
Savannah,
What you are talking about is sometimes refered to as "dragging it in". I used to do it a lot, not so much anymore. It's very possible to get so slow that you don't have enough power to arrest the sink rate and you are going to "drop" test your gear. To me that's being behind the power curve.

zane wrote:There was a recent thread on supercub.org about steep takeoff climbs with flaps, and how in the event of an engine failure, there is simply not enough airspeed to continue flying power-off....obviously catastrophic.

Then you're back to the old Cub maxim... "Just barely fast enough to kill you!"

100 years ago when I was learning to fly ( at BCW with Harry Doyle ) he told me to practice dragging my SC tailwheel down the runway using the throttle and thats what the power curve is all about. Not a good idea in a low powered a/c

GumpAir wrote:

zane wrote:There was a recent thread on supercub.org about steep takeoff climbs with flaps, and how in the event of an engine failure, there is simply not enough airspeed to continue flying power-off....obviously catastrophic.

Then you're back to the old Cub maxim... "Just barely fast enough to kill you!"

Or as Maxwell Smart used to say, Missed it by That Much

I have used this style of landing with my Cessna 182 in the past. If you look on Youtube.com under skybobb videos and check out the landing at the Owyhee. It is listed under Landing at Owyhee Res. (28U). This strip is 1840 ( which is not to short) but it shows me getting down on the end of the strip and under a slow speed. If the engine quits we get to check out our swimming techneque. enjoy. Bob

I don't think were all on the same page here.

I am not talking about dragging it in.

There isn't always room or winds to do so. I am talking about a stabilized approach then, getting that nose up, coming down, and arresting it in the last 30-40 feet.

You can do what you want its the last 30' that counts and it is definitely by feel.

You better know how that first feel of the bottom going away feels, or you may be to late.

mr scout wrote:I don't think were all on the same page here.

I am not talking about dragging it in.
You better know how that first feel of the bottom going away feels, or you may be to late.

Me neither. I'm talking about using ground effect to slow the airplane below indicated Vso and still be flying. Slowest possible speed thru the air/across the ground prior to wheels touching to land.

Might be combined with "dragging it in" but the two are apples and oranges different critters.

Gump

mr scout wrote:I don't think were all on the same page here.

I am not talking about dragging it in.

There isn't always room or winds to do so. I am talking about a stabilized approach then, getting that nose up, coming down, and arresting it in the last 30-40 feet.

You can do what you want its the last 30' that counts and it is definitely by feel.

You better know how that first feel of the bottom going away feels, or you may be to late.

I may be mis-using the term, but to me, that's dragging it in. If done correctly touchdown is at the highest power setting of the approach.
Believe it or not, it's similar to an approach in a helicopter, except as long as HOGE (hover out of ground effect) power is available, a go around is easy. But if your heavy and high DA, then about the time you lose effective translational lift you have better be close to ground effect.
Same with the airplane, about the time you get below stall speed, you better be in ground effect, and quick with your feet, because you will need a lot of right rudder.
Believe it or not, but ground effect starts at approximately whatever your wingspan is.

I guess its in our perception

To me, Dragging it it is a flat nose high power on approach at a slow speed.

You don't need this type of approach to get down get into ground effect and use whatever power is needed to hang below VSO while in ground effect.