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Do you get the stall warner on takeoff?

MedEwok wrote:

I feel vindicated in climbing rather fast and shallow than slow and steep. The only reason for the latter would be terrain in front of you during the climb, right?

My preference will be to fly a faster climb whenever topography and obstacles permit. Airspeed is your friend, particularly in the case of an engine failure. Those silly pilots who needlessly hang their airplanes from the prop on mismanaged “STOL” takeoffs are just setting themselves up for a really bad day if the engine quits, and they are setting up other pilots who might copy their foolishness. Yes, I will happily get the plane off the surface with the stall warning peeping, particularly from a soft runway, or off rough water. Then, I will lower the nose, and accelerate to a safe climb away speed – the faster the better.

My sense of importance for this comes, in large part from flight testing I flew in a Cessna Grand Caravan years back, where it was necessary to test a slower than POH climb away speed. The POH specified 87 KIAS, and it was necessary for me to test at 80 KIAS. It seemed fine, until I was required to demonstrate a land back from 50 feet following an engine failure. That testing was the most demanding and stressful flying I did on that program (including a dozen spins on that plane). Ultimately, I validated Cessna’s numbers, as I could not succeed in demonstrating the power off land back in the modified Caravan, and darned near wrecked it testing. Since then, I’m a true believer in maintaining suitable flying speed for a forced landing at the earliest point in the climbout when you can achieve it. This does not preclude a short takeoff/soft field takeoff/stall warning during lift off, just not increasing your altitude needlessly at a slow speed.

Home runway, in central Ontario, Canada

Pilot_DAR wrote:

My preference will be to fly a faster climb whenever topography and obstacles permit. Airspeed is your friend, particularly in the case of an engine failure

I would say this depends on the length of the runway and the obstacles at the end of the runway. I also prefer climbing at higher speeds but if you have a 2000 m runway with a forest at the end, you want to stay over it as long as possible and climb as high as possible before you get to the forest. You just need to be ready to push the nose down fast without hesitation in case of an engine failure, as a recent video from FlightChops has shown.

^ESM[ES]$, Sweden

Dimme wrote:

climb as high as possible before you get to the forest.

I don’t agree with this, in the context of obstacle clearance on climbout following takeoff. You need to clear any obstacles with a comfortable margin, of course. Thereafter, being needlessly high, and slower than a comfortable glide entry speed means that in the case of an engine failure, you’ll have to surrender some of that altitude to achieve a suitable glide speed, before you begin your glide to a forced landing. Too much configuration change for my liking. The less configuration change is required when something goes bang, the better. When it goes bang, you’re already busy enough, to have to thereafter reconfigure, and risk a stall and loss of control, when the alternative would have been to simply lower the nose, and maintain the speed and control you already have. Whether you can glide to a suitable forced landing area is always an open question, but when you’re committed to do it, the outcome will be better if you changed fewer things to achieve that.

I would like to get to the forest so as to clear it comfortably, and thereafter be at or a little faster than Vy if possible. I do not want to be 250 feet over the forest at Vx. Pushing the nose down fast means dramatic configuration change, and room for sloppiness in the rush, over control, risk of stall, and having to recover the drastic pitch change you just induced. I enjoy maneuvering, and aerobatics – at altitude, and in planned circumstances, not close to the ground in a panic.

I admit that I have not watched many flight chops videos. I have not pursued watching more, as the couple I watched some time ago had me thinking that the chop should have been at the beginning of the video, rather than the end. The ability to create a video is not an automatic endorsement of the content. Approach with caution, they may be more entertainment than compliant training material.

Home runway, in central Ontario, Canada

My idea was to have remaining runway to land on, not the forest. I don’t disagree with what you say, just different situations different actions.

^ESM[ES]$, Sweden

Even with everything equal as same obstacle clerance, I expect more chances of a bang on the engine by flying steep and slow

ESSEX, United Kingdom

Pilot_DAR wrote:

Thereafter, being needlessly high, and slower than a comfortable glide entry speed means that in the case of an engine failure, you’ll have to surrender some of that altitude to achieve a suitable glide speed, before you begin your glide to a forced landing

I wouldn’t say I disagree. But, Vx is comparable/similar to the speed of least descend rate and Vy is comparable/similar to the best L/D. Vx is therefore already a good speed for a forced landing (in the woods) because it is slower than Vy in both x and y direction, less energy.

Vx is therefore already a good speed for a forced landing

Because excess propeller thrust is maximised at a LOW density altitude close to Vs, it is correct that it is close to minimum sink speed. Vx will move towards Vy, and therefore down the lift dependant drag curve, as thrust reduces with density altitude.

However the power on deck angle/pitch angle is very different to the Vmd pitch angle power off, in some STOL aircraft dramatically so (around 30 degrees in the case of a Suer Cub).

Also on a typical GA wing design that is aimed to stall from the wing roots outwards (either because of slab wing design, washout or stall strips on tapered wings), the sudden loss of thrust in a Vx pitch climb is likely to result in a sudden wing drop. The wing roots are close to stall, but propeller slipstream is creating induced airflow that reduces effective angle of attack at the roots. This is the reason why aircraft with very benign stall characteristics, suffer wing drop in power on stalls, even while in balance. The same effect comes from use of flaps – increased camber reduces critical angle while increasing coefficient of lift, in effect leading to wing tips stalling first power on.

In short received wisdom is to accelerate to Vy in ground effect and then pitch up. The Super Cub full flaps Vx at 45 MPH IAS, is purely for YouTube.

Don’t be a lawn dart :)

Enstone (EGTN), Oxford (EGTK)

LeSving wrote:

Vx is therefore already a good speed for a forced landing (in the woods) because it is slower than Vy in both x and y direction, less energy.

Yes, at the point of touchdown. Prior to touchdown, faster than Vx leaves you more margin for maneuvering, and an effective flare, with a little wiggle room for imperfect execution. Yes, it is possible to descend power off at Vx, or slower to as slow as Vs. But, when you do that, you have left yourself no stored energy with which to arrest your descent. You’ll just continue into the ground when you pull to flare. Robertson STOL Cessnas are famous for this, they will happily fly so slowly that you pull to flare, and there’s nothing left. And… If you approach too slowly power off, you have reduced your variability in touchdown point. If you misjudged, and land short, you’re going to hit whatever “short” is, at flying speed. If you carry that extra speed in the glide, and even can’t slip it off at the end, you still have your entire intended roll out area to slow the plane, before you hit whatever defines the far end of your selected spot. At least if you crash at the far end, you’re going a lot slower that you were ate the near end!

RobertL18C wrote:

In short received wisdom is to accelerate to Vy in ground effect and then pitch up. The Super Cub full flaps Vx at 45 MPH IAS, is purely for YouTube.

Yes, and every one of those videos should have a “don’t try this” warning!

Home runway, in central Ontario, Canada
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