Performance Take Off's

[Slick Goodlin]

Notably there is no O model (or I model)

You mean I’ll never get to fly a Cessna Seventeen Twenty or Twenty One? Damn.

[Colonel]

there is no O model (or I model)

That kinda makes sense to me. Getting rid of confusion is always a good thing.

The difference between 0 and O is not obvious to everyone.

[Slick Goodlin]

I was wondering if someone had a simple chart that illustrated the settings, speeds, and basic procedure for short field take off with and without obstacle and soft field takeoff with and without obstacle.

In my work flying it’s often said that there is SOP and there is Technique. SOP (Standard Operating Procedure) is a sort of technical bare minimum that will do its best to ensure you’re not trying to start and engine with a fuel valve off, or begin an instrument approach without knowing what the minimums are, or landing with the gear up. Technique is a little more free-form approach where you understand the situation and apply what’s needed for it on a case by case situation. I would group performance takeoffs into the latter.

Most performance takeoff training is dumb, IMO. I understand how it got to where it is; generations of instructors pushing students through imaginary scenarios focused on some theoretical maximum and risk be damned, then in many cases the student becomes an instructor and continues the cycle. What you end up with is this weird focus on making these takeoffs as dramatic as possible. I’d rather you know what factors need to be overcome and then apply what the specific airplane needs to do to accomplish it. Sometimes I refer to this approach as learning to fly an airplane instead of just learning to fly your airplane.

Short field: in training these typically have a hard surfaced runway and an obstacle. Essentially you want to get from a dead stop to as high as you can in the shortest distance. You know once you’re flying that the most altitude gained for distance is at Vx so now you just need to get to Vx ASAP. That’s best achieved by lining up on the runway as close to the threshold as you reasonably can, doing a static run up before brake release, and if your plane has a rotate speed try and be fairly precise on it. Once airborne accelerate to Vx.

Places where I think it’s silly to get too extreme include taxiing so far back to the threshold that you drag a wheel through the grass, forcing the nose down on the takeoff roll (in a trike), and a worm-burning acceleration to Vx a half inch above the runway surface before horsing the nose way up. All unnecessary risks IMO. I’d rather just not be wasteful of runway when lining up and once airborne accelerate to Vx in a shallow climb that has you on speed at about half a wingspan high.

If flying a trainer to the extreme is the only option holding that line between life and death just wait until it’s cooler, or there’s a ten knot wind blowing down the runway, or shed a bunch of weight before going.

Soft field/Rough field: here your obstacle is the rolling resistance on soft ground and/or the fact that these surfaces are probably not kind to the nose wheel or tailwheel of your airplane. Stopping is often a poor life choice in case you start to sink in so it may require a rolling start as soon as you go onto the runway. Wait until pointed down the runway before you really give her the beans and give elevator control as required to unload the little wheel. You’ll feel when the nose wheel or tailwheel stops bouncing along the surface and from there you just pitch a hair more so it doesn’t clip a big bump, and wait until the whole airplane flies off on its own. I suppose there’s a chance a nose dragger could reach rotation speed before that happens in which case you rotate. If you’re below Vx as you rise of the ground (you probably will be) then accelerate to at least Vx before getting serious about climbing. If there are no obstacles to climb over then Vy probably makes more sense.

The silly exaggeration here is holding a nose wheel waaayyyyy too high up and risking banging the tail off the ground. This is a matter of finding what’s enough and going with that. Risks in the acceleration before climb are the same as with the obstacle takeoff.

Any direction found in your POH beyond the above of course supersedes what I’ve written. Also don’t just take my word for it, talk to a bunch of pilots, take in what they have to say, and start putting together what sounds most reasonable to you.

[Colonel]

Most performance takeoff training is dumb, IMO

If all you ever fly off is long paved runways at certified airports in flat land at low density altitude, yes.

I would agree with you that 90% of Canadian aviation resembles that.

But where I live, if you fly a few miles east, you’re in the Rockies in often warm temps and very high density altitude.

It’s nice to know Vx sometimes.

Note that a corporate jet crashed at Truckee not too long ago, when he attempted to maneuver before landing instead of a four bars straight in.

Try flying a buck fifty at Leadville on a warm summer day.

Most private pilots don’t even know to lean the mixture. One of them was whining last week that he had a plug fouled in takeoff.

Duh. Self-inflicted wound, and you want sympathy?

[David MacRay]

I’m reasonably certain he meant the techniques being taught too often are bad, not learning to do a proper performance take off is dumb.

Thank you for typing that out Slick. I don’t want to be a bad influence on TwinOtterFan, who has to play along with instructors for a while to finish his licenses but I have also lost the ability to pretend a person that is supposed to be teaching me, is just right every time by virtue of being an “instructor”.

My favourite is when I used to particularly enjoy doing a nice forward slip to lose altitude. Many instructors held on as if their seatbelt was about to fail and they were at risk of falling out the windshield.

“Oops, sorry pal. First time slipping a small aircraft? This was pretty normal flying back when I got a PPL.”

Fair enough they may of been suspicious about me.

I had developed the bad habit, of coming in too high and a bit hot followed by slowing down and trying for the numbers, from flying into large busy airports with mile long runways too much.

I’m annoyed so few of them could recognize I could get a 172 transitioned to 65 knots and nice and low over the threshold.

It took me too long to realize 65 is still a bit too fast. Again maybe a good instructor of which though they seem the minority, I have had several (and I feel like it’s important to mention the last one was excellent,) would have mentioned that.

[TwinOtterFan]

Thanks to all again,

I started out on the P model which the POH stated flaps 10 for any performance take off, I just switched to the M model and it was a bit different, using flaps 10 for soft field with or without obstacles, and short field with obstacle.

My FTU had a student tailstrike yesterday while practicing soft field takeoffs.

[David MacRay]

My FTU had a student tailstrike yesterday while practicing soft field takeoffs.

I’m trying to imagine how that even happens. Someone yanking the yoke like they were trying to pull a regional three bar off their sister?

[Slick Goodlin]

I’m reasonably certain he meant the techniques being taught too often are bad, not learning to do a proper performance take off is dumb.

Nailed it.

Being capable of using your airplane is important. Not being pointlessly dramatic is also important. I might suggest that the extreme minimum short field with an obstacle at a high density altitude and a plane at max gross is maybe not in a student pilot’s wheelhouse. Maybe it shouldn’t be in anyone’s.

The Colonel often talks about how he’s still alive through leaving margins and not doing dumb things; this is that except at a little different stage of flying.

[David MacRay]

Hey being frightened of my flying is great fun, just don’t expect to be impressed or join in the act.

[TwinOtterFan]

Just wanted to add that I am prepping for my flight test and I find like most government exams and test what they want to see on the test is not always the way people do things "in real life" it was the same in military.... there is a way to pass the test and then an actual way to perform. Also something I never understood. In the Army I assume it was because the people designing the test were bean counters in Ottawa.