stall warning and when to panic

[cockney steve]

I was fortunate to accompany a friend in an Aeronca Chief, on several occasions. On one of our "doss-abouts" he stood it on it's ear and did a 360, culminating in a jiggle as we flew through our own wake....it wasn't a fluke, he could do it at will (as I remember, it was a "still-air" day. My attempt....crank it over, pull back and a bit of opposite rudder....nowhere near...but there was no mush, buffet or other untoward feedback. Happy days, Armstrong starting and an Icom handheld...when he got a portable intercom.....LOOXURY!

[Shaggy Sheep Driver]

if you were at the top of a loop, wouldn't your vortices actually go up?

Vortices only occur when the wing is loaded. At the top of a loop the wing is very lightly loaded, maybe even zero loading if the loop is ballistic. So vortices would be negligible or absent. But I guess if there are any, they'd go down relative to the wing, so 'up' relative to the ground!

[barit1]

Hangar flying

When I took my instructor's check ride, the FAA guy asked for the typical Lazy Eight and chandelle demos. Lazy Eight met his approval, but he didn't like my chandelle. "Stall warner was sounding for 5-10 seconds solid" - well, yes, that was how we did them. So I asked what he wanted. "Just an occasional beep" was his goal.

I said "Can I do it again?" - and he was satisfied this time.

The difference, of course, was that I had been practicing recovery with a bit of burble - itself a reliable stall warning in a C150 (or in all the other light singles I had been flying). Attitude and feel = old school. The examiner was of the "by the numbers" school and expected his candidate instructors to follow suit.

But I think he respected the fact I could adapt, and demo both styles.

[phiggsbroadband]

Hi Barit1, the Lazy8 is not taught over this side of the pond, either in PPL or Basic Aerobatics... Which is a bit of a shame.
We also don't seem to do 'Turns about a Pole' which is another of your favourites, (especially in a crosswind).

[barit1]

The lazy eight is valuable because you are continually moving in all three axes; nothing is static! You learn the flow of the maneuver - up, roll, yaw, reverse roll, back to S&L...

[Desert185]

Barit1

I'm one of those guys who never understood the need for a Lazy 8 in training, nor any benefit it might provide in my future as a professional pilot in any airplane under any circumstances. After almost 47 years, my opinion has not changed, and the fact that it is not required in some areas of the world with resulting capable pilots seems to confirm my suspicions.

Pylon 8's? Yes. Good value to becoming proficient in those.

[Piper.Classique]

The base would be a tangent to a circle with centre at threshold, the turn to base being started abeam the threshold.
So the base is actually a much more constant distance to the runway than your normal circuit.

If you think about aiming points and such, this is much easier to judge and adjust. Just a slight modification of a spiral where your aiming point would be completely constant, hence, constant aspect approach.

Ah. Yes, now I understand what you are saying, once you say start the turn abeam the threshold. We call that a PTU here, prise de terrain en U. But there is no need to work out the angles, it is simply a U turn, half a circle with bank angle varying to adjust for the wind. Not an unusual technique when teaching proper stick and rudder flying and, dare I mention it, judgement.

[mad_jock]

What's plyon 8's?

I agree on the lazy 8's did them once they are just a coordination exercise with nothing really gained for the real world.

I have never felt I have missed out by not doing them properly. The time could be better spent flying the aircraft without any instruments through a series of trimming in different configuration exercises just setting everything up by ear and attitude.

[phiggsbroadband]

Whilst model flying, I used to be able to do half a dozen lazy8s, continuously one after the other. The trick was to use 80% of 'cruise power' so that there was no height lost or gained.


Also the same 80% power was useful for holding a continuous Dutch Roll on the model plane... I have not tried a Dutch Roll in a full size Cessna, I can only imagine it would spin out on the first excursion.

[Shaggy Sheep Driver]

Dutch roll? That's not a manouvre, is it? I understood it to be an undesireable flight characteristic of an aeroplane with insufficient yaw stability, cured by fitting a yaw damper?

I found PA38s do it in rough air.

[Genghis the Engineer]

Dutch Roll is a coupling of lateral with directional stability driven by sideslip. Pretty much any aeroplane will do it, most can be induced to do it deliberately by a sinusoidal yaw input called a "rudder doublet" and many will do it in turbulence. Many birds deliberately induce then damp it as a means of making rapid heading changes, although we don't use it deliberately in aeroplanes.

A yaw damper is the most common fix in more complex aeroplanes to eliminate unwanted DR. It's not the fix you'd normally use in a small aeroplane, where you'd more likely change the shape or size of the fin.

G

[mad_jock]

If you don't want to fit a yaw dampener you can just design a really stupid looking aircraft instead.

[phiggsbroadband]

To fly the Dutch Roll (in model flying) I used to get the plane flying away from myself at 80% power, with almost fully back on the stick, to give a high nose attitude slow flight. Then a quick dab of rudder would make the plane bank 40-60deg to the left, followed by the same to the right, then to the left... etc etc. The only Input I had was to hold the stick almost right back to hold the altitude. Release the back pressure before the model went out of sight... and then RTB.
It is true that the flight path is stable, the plane keeps flying in a straight line.. Just wobbling R+L+R+L....


btw Jock.. What is a Yaw Dampener? Is it an Electronic Gizmo Box of tricks, or something mechanical.

[barit1]

Yaw dampeners used to be simple fluid dynamic "computers" (either pneumatic or hydraulic*) tuned to counter the airplane's natural period. Today on big jets they're probably just a chip or two on the FBW system.

* Analogous to the hydromechanical engine fuel control of past decades...

[fireflybob]

On the aircraft I have flown with such devices it's called a Yaw Damper rather than "dampener"!

[mad_jock]

Depends which country the manual is written what its called.

[Desert185]

mad_jock:

Eights on pylons - Wikipedia, the free encyclopedia

[mad_jock]

I have survived with out doing them either.

[Desert185]

...and I can survive without Scotch, but I choose not to.

[mad_jock]

Dear god Scotch that's another dirty habit.

Try single malt whisky instead.