hotrod180 wrote:

contactflying wrote:.....Full flap trim is the same as cruise trim in most smaller Cessnas......

I disagree. In my ragwing C170, my C150/150TD, and now my C180, I have to trim to extreme nose up to achieve anywhere near hands-off approach speed.

I'm with you. The 172 I borrow sometimes with a Horton kit requires full nose up trim for approach and will actually still be quite a bit too fast without any further backpressure on the elevator. My 150 is similar but it seems like full trim gets you pretty close to the 50 or so MPH I usually use for approach.

Come to think of it, I'm not sure I've flown anything that could use anything close to cruise trim for approach. I think maybe our signals are crossed somewhere.

Hotrod 180,

You are right for a good slow power/pitch approach. Cruise trim is for 1.3 Vso at full flaps. Using the apparent brisk walk rate of closure approach, we don't get to the good slow power/pitch approach stage until short final. For the short ride from short final to the numbers, we just add elevator to maintain the apparent brisk walk and add power to control the extra sink from the reduced pressure airspeed on the wing. You have probably noticed that things tend to speed up a bit from short final on down unless we raise the nose a bit to slow more. Now we need to add a bit more power. Thus we are eliminating the need to round out and hold off. We still need to flair.

The slow, steep, stabilized power pitch approach leads to a Navy type plop it down or a modified round out and hold off. The drag it in approach doesn't, because the gravity thrust is already eliminated. However, tricky throttle closing is necessary to hit the spot. This too, can lead to a plop down.

Thanks for the clarification. Cstol and I were thinking in terms of the apparent rate of closure approach that stabilizes apparent rate rather than airspeed. On short final there is some change, more or less depending on gusts, in rudder, elevator, and throttle movement. Cruise trim, full flaps, and whatever airspeed generally work fine until short final. You will notice that the apparent rate of closure with the numbers changes little, at any speed, from pattern altitude down to about four hundred feet and a quarter mile. You and Patrick are right about good steep, slow approaches though. If not pretty slow by here, it gets hard to lose both gravity thrust and engine thrust in time. All slow or slowing approaches are good.

Contact

Agh! We're drifting. This was about pitching up too much on takeoff. Hotrod 180 start on on steep, slow, power/pitch approaches. How does yours differ from Patrick's?

Just curious, some of you mentioned seat sliding back. My 172 has the emergency stop mechanism, it works kinda like the seatbelt in a car. Once you move too fast it locks up.

I was wondering has anyone had the seat unlock and get caught by the emergency mechanism? I am curious how well they work.

IF that's what happened here (maybe not), the emergency seat stop may have made a BIG difference.

ShadowAviator wrote:Just curious, some of you mentioned seat sliding back. My 172 has the emergency stop mechanism, it works kinda like the seatbelt in a car. Once you move too fast it locks up.

I was wondering has anyone had the seat unlock and get caught by the emergency mechanism? I am curious how well they work.

IF that's what happened here (maybe not), the emergency seat stop may have made a BIG difference.

If it's adjusted properly, the auxiliary seat stop doesn't unlock until after the main lock has been pulled free from the track, when you lift up on the lever. If you peek under the seat at how the two locks work, you can see that the peg could come out of the track without affecting the auxiliary seat stop at all--the lever unlocks both of them, but other than the lever, they're not connected together. The retracting reel is made by AmSafe, the same folks that make the inertial seat belt reels for cars, BAS harnesses, and others, but instead of being unlocked and then locking because of inertia, the reel is locked all the time until it is unlocked by pulling the lever.

Cary

contactflying wrote:....Hotrod 180 start on on steep, slow, power/pitch approaches. How does yours differ from Patrick's?

Not sure what your question is.
Which Patrick are you talking about, and what is his approach?
My approaches all start about the same, slowing down as I enter & proceed in the traffic pattern, whether it's a glide-in type approach (carrying a little power), or a nose-high moderate-sink-with-power final, or some combination of the two.
I have to admit that I've never understood a lot of your terminology: "apparent brsk walk rate of closure", "energy pressure of airspeed", etc.
But I will stick by my statement that my last three Cessnas have required a lot of nose-up trim to hold anywhere near an appropriate speed in the pattern (and esp on final) without holding a lot of back pressure.

Hotrod 180,

Patrick Romero teaches a wing flat with horizon slow power/pitch approach in his STOL Tips articles. It is much like what Wolfgang (Stick and Rudder ) calls the stall down approach.

Stabilized apparent brisk walk rate of closure approache is when we use elevator to keep what appears to be a slow rate of closure with the numbers. From about 500 feet up and about one quarter mile out, keeping this apparent rate from speeding up will cause a continuous slowing until we lose vision of the numbers.

If you are constantly slowing (having to increase trim up,) we are on the same page. All pilots perceive this apparent rate of closure and some respond to it by slowing to keep it slow. We all do this when we stop our car at an intersection. It works the same with the airplane. We just don't come to a stop because we lose visual of the stop sign /numbers and do a rolling stop.

Apparent rate of closure approaches have been taught Army helicopter pilots over fifty years. I agree it is not common terminology in the airplane world, but it should be. More airplane pilots use it than think they do. If you are getting down on or near the numbers without a bounce, your mind is probably seeing and your control technique is probably responding to the apparent brisk walk rate of closure with the numbers.

*Patrick Romano, author of our STOL Tips series