Would it not be easier to teach new pilots to use the needed control imputs to align the airplane in the direction and attitude that is desired to fly the intended path?

Rather than all this mental mastrubation on how to describe the manouver how about this.

Here is a hint.

Picture this:

Our dedicated instructor is demonstrating a X/Wind landing.

The wing is lowered sufficient for the strong 90 degree X/Wind, however the longitudinal axis of the airplane is 30 degrees off the runway heading.

As the airplane firmly contacts the runway and wipes the gear off the student asks, was that a side slip? :D :D

Tha instructor answers, I am not sure, I will post on Pprune and ask. :D :D

Cat Driver:

No difference aerodynamically. The problem comes when trying to relate the manoeuvre to some ground reference.

Forward slip: Crossed controls are used in such a way that the flight path remains unchanged from the previously balanced flight path.

Example: (Nil wind for convenience) A slip is flown to maintain final. Previously the a/c was maintaining its flight path parallel to its longitudinal axis. A/c is yawed 'away' & rolled 'towards' the previous flight direction. The a/c maintains its original flight path but now with a new & different heading.

Sideslip: Crossed controls are used in such a way that the flight path deviates by some angle from the previously balanced flight path.

Example: (Nil wind to maintian commonality with the forward slip example) A slip is flown to impart a lateral component to the flight path eg to correct a displacement from final. The a/c is rolled 'away' & yawed 'towards' the original flight direction. The a/c maintians its previous heading. This results in a new & different flight path but with its original heading.

Mental masturbation is the perfect word for it:

I enjoy tossing around ideas and thoughts purely for my own pleasure and interest. PPrune is a good place for this because you can either choose to discuss these things with me or skip to a different forum.

Of course, as an instructor, I would like to approach these things from a "how to" perspective. "lower the wing into the wind and hold the plane straight with rudder" is about all the private pilot needs to know about slipping into the crosswind. "dip the left wing and stop the turn with rudder" is great for losing altitude.

"create an angle between the relative wind and the longitudinal axis of the aircraft by using aileron into the wind and opposite rudder, so that the path along the ground maintains a straight track in line with the centreline of the runway, bearing in mind there may be an increased rate of descent" would be the wrong thing to say while drifting off course on short final and into the control tower.

I just want to make sure I have ALL of the detail straight in my head so I don't teach anything wrong. i've overheard too many instructors teaching theory wrong (sideslips being a prime example), and i hope I never become one of those.

Thanks for the chuckle, anyway chuck.

btw. I'm not a flight instructor, just doing the rating now, and trying to develop a system that is good. If I sound like I'm talking out of my as s sometimes, it's because I am. everything i know now is from books and conversations. This is why I'm here: to get feedback from experienced instructors. Many instructors where i work don't seem to be as interested in discussing instructional techniques... more interested in talking about the airbus they hope to fly next year. Feel free to tell me what's what if i sound full of s***.

Is that really a published definition? Because don't those words also fit staying on the localiser in a cross wind where the mislaignment is merely your drift angle?

Cheers

airframe stress?
 

I quite a enjoy a good bit of side-slip; one of the best moments in my limited flying experience was a 'game-over' type botched PFL that ended up with me hurtling over a field in a full slip towards high trees with an astonished farmer looking round at my side-ways flying aircraft. Have also used side-slipping occassionally to expedite descent when necessary, having early on in my flying training been shown how to drop through a cloud layer using in a full slip, achieving more than 2500ft/min!

But, on a PA-28-151 checkout recently, in the US, the instructor intervened when I started side-slipping during the PFL, claiming it would put too much stress on the airframe (that particular one was 30 years old, with a few cracks right enough). Could there be some truth in that, or just a myth?

I also sometimes have this nightmare that when flying something with stiff heavy controls like a Warrier, I'll suddenly feel a 'snap' and the controls will be feel full and free like never before.

farley: No, not a published definition, just my understanding of a forward slip; and no, what you're describing is not a slip at all. in Canada, we call it a crab, when the relative wind is still in line with the plane, your track is in line with the runway, but your longitudinal axis is shifted into wind.

I think the Flight training manual basically emphasizes the difference is in the PURPOSE of the slip.
Lose altitude: forward slip
Change your track (or maintain a straight track in x-wind) without changing heading: side slip

Ok, so I used to side-slip in a 152 when I was training. Now flying a 150, so would assume that slipping with full flap (40 degree) is a no no. Any thoughts?

The "forward slip" thing is a US term.

There was a lengthy discussion on it in this thread some time ago.

If you go to the FAA website and have a look at some of the documents there (I gave some references in the above thread) all will be revealed ... but I still can't see what the difference is between the "forward slip" and the good old garden variety sideslip ... other than the picture outside the cockpit. Does that mean I am a dinosaur tried and true ?

To some,all very confusing this 'forward' and 'side' business from over the pond!

As I see it you'd be hard pressed not to be going sideways when slipping through the air - try it with the windows open, chaps, it gets windy on one side or the other! So the term 'forward' slip is bound to be a little inaccurate as you can't actually do without the sideways bit and still be slipping.

Presumably, the term 'forward' is trying to describe a slip where the flight path and ground track coincide with the extended centreline of your runway or airstrip (since all slips that aren't turning,by definition, have a constant direction over the ground ie track - wherever that may take you.. ).

Slipping turns are simply slips that have insufficient rudder applied to prevent the machine from changing heading.

Read your Biggles:D

PS shocking that anybody could confuse crabbing with slipping...

bcpilot

Sorry old son that was not me describing a crab it was you.

I just quoted exactly what you said.

What you needed to include in your words to make them a description of a forward slip was a little bit about "with the wind down the runway"