Why do planes spin?

[Mobius]

Indeed. That's why I always thought stalling & spinning should be part of the PPL syllabus - before a student is allowed solo - as it was in my day.

It was for me as well, we had to do it before starting to learn to land, I even think it was one of my first couple of lessons.  Not spinning though, my instructor tried a couple of times to put a Cessna 172 into a spin, but they don't spin very easily, so he actually couldn't do it.

[Hagar]

It isn't?

They call it "spin awareness" or "spin avoidance" nowadays. I'm not sure what this involves or at which point during training it's covered but I'm told the practical spins & recovery that were once compulsory are now discouraged if not forbidden. I believe it's very difficult to spin some modern trainers so it wouldn't be possible anyway. If this is the case I can only think that there must be a considerable number of qualified pilots out there today that have never experienced a spin & have very little idea of how to recover from one.

[Brett_Henderson]

During my initial training (many moons ago), spin recovery was "required", by my instructor. My first spin was in a 140hp Archer.

A couple years ago, when I started flying again, I requested spin recovery practice. Spun both a Tomahawk and a Skipper. And of course for the CFI certificate, you must complete spin recovery training.  No spinning in C172s for me (that I'll admit to). For one.. it's tough to get them to spin..And two, with me @ 220lbs, with an instructor.. the CG is too far forward for utility loading (and too heavy for utility loading with someone in back).

Nowadays, it's like Hagar says.. Spin awareness.. As in: add a little rudder during a stall and feel the plane yaw and roll.

I've mixed emotions about mandating spin recovery. People wiser than I have made those decisions. But I think a pilot should take upon himself to seek spin training.

[Brett_Henderson]

Too bad they never made a 4-seat version... how would you say the Beech Skipper compares, in terms of utility?

I love the Skipper too, but if I remember correctly, its useful load is evn less than a Tomahawk, by 15 lbs or so. I think they're both delightful planes.

I've seen where some people have installed 110hp engines in Tomahawks,, which really just makes them a tad faster and safer. That doesn't raise their certified, useful load though (that I've seen, anyway).

I think.. with modern engines (more HP / same weight) and little reinforcement of the landing gear and wings.. A Tomahawk could easily carry another 150lbs.. Which would make it a great, two-seat touring plane..

[beefhole]

I actually just now realised I haven't had any spin training at all-spin 'awareness' or full spins or whatever (after making it sound as if I had-d'oh ).  Will have to go up with an instructor some time.

[C]

I actually just now realised I haven't had any spin training at all-spin 'awareness' or full spins or whatever (after making it sound as if I had-d'oh ).  Will have to go up with an instructor some time.

Well worth doing. Try reading the spin recovery placard in the cockpit whilst you do a spin...

[chornedsnorkack]

Again, this will depend on the aircraft, or more specifically the type of wing. A typical trainer with a flat-bottomed lifting wing section & large dihedral angle on the mainplane might well turn when bank is applied. Being inherently stable it will return to straight & level flight when the controls are centralised. On the other hand, a high-performance type with a semi or fully-elliptical aerofoil section & little or no wing dihedral will have no tendency to turn when rolled. It will stay where it's put in the roll axis when the ailerons are centralised. When banked the lift will decrease & the nose will drop without opposite or "top rudder".

Let

[Hagar]

[quote]Let

[chornedsnorkack]

One comment. Not sure I understand what you're getting at here. Which direction is it accelerating sidewards?

If a plane is banked, then the lift still operates at a right angle to the wing - but no longer vertically upwards. Thus, as the lift is tilted from the vertically up direction towards the lower wing, the plane would accelerate towards the lower wing.

If the downward acceleration has any effect on AoA it would surely decrease it.

Surely it would increase?

If the pitch, the angle between wing and horizon, stays unchanged, but the plane accelerates down, the relative airflow is no longer coming horizontally - it is coming from an increasing angle below the horizon. Thus the AoA between airflow and wing should increase.

[Brett_Henderson]

Let's consider, say, an airplane banked by 6 or so degrees with no compensating changes to pitch or thrust.

Just guessing, but by ratio, I'd guess that those fractional accelerations are the displaced lift of 1G from level flight... And the "sideways" vector is relative to the earth.

[Brett_Henderson]

Surely it would increase?

If the pitch, the angle between wing and horizon, stays unchanged, but the plane accelerates down, the relative airflow is no longer coming horizontally - it is coming from an increasing angle below the horizon. Thus the AoA between airflow and wing should increase.

You're splitting hairs here, and over-simplifying things. If the plane is "falling".. and that rate-of-decent, as compared to forward airspeed, is enough to change the AoA.. Then the turn would start becoming more of a control surface thing (with the banked wings accelerating downward being the control surface).. so THAT acceleration would counter it all (relative airflow) and again make the AoA be a decreasing thing.

[FLYING_TRUCKER]

Interesting read and so many correct answers.  ;)

In my humble opinion taking spin training out of the Private Pilot curriculum is or would be a very big mistake.

It should also be mandatory for Flying Instructors.

I would also like to see some limited aerobatic instruction taught in the Private Pilot Course however I do realize this does add to the cost of the program.

I would suggest though once you have obtained a flying licence like the "Recreational Permit or the Private Pilots Licence that you take it upon yourself to seek out an Aerobatic Instructor and obtain five (5) hours of theory and actual flying from him.

I think you will be amazed at what you just might learn.  :)

You will also find yourself with a tiny bit more confidence and flying ability if the tower controller advises you of the possibility of wind shear or wake turbulence.

Cheers...Happy Landings...Doug

[chornedsnorkack]

[quote]

Right you are... although given enough altitude, some aircraft, will go through these oscillations several times while losing energy, and if they have a healthy dihedral and the air is calm, dropping a wing is unlikely. The Cub is a pretty good example of that, and many trainer-types like the 150 and 172 will also "schwoop" a few times rather sedately when left to their own devices after a mild stall

[C]

I would also like to see some limited aerobatic instruction taught in the Private Pilot Course however I do realize this does add to the cost of the program.

A little more expensive it may be, but all to often now we hear of people who have not been taught aerobatics, or even know how to go about performing them sensibly, killing themselves. Even worse would be doing them untaught without any spin training, or experience of incipient spin recovery, most likely to happen if mishandling aeros.

A lot less costly than dying anyway.

[beaky]

I actually just now realised I haven't had any spin training at all-spin 'awareness' or full spins or whatever (after making it sound as if I had-d'oh ).  Will have to go up with an instructor some time.

Take at least an hour of aerobatics dual sometime in an approved airplane... lots of fun, and it's a good confidence-builder, as well as being educational.
The rental rates on C152 "Aerobats" are usually about the same as a stock 152; that'd be a good first-time choice.

Reminds me I haven't actually done full spins yet (my one aerobatic lesson didn't include vertical-line maneuvers because the vis. was poor that day, bad horizon); I should remedy that.

Did about 1/2 turn once in a Skyhwak during my PP training after practcally begging my CFI; kinda disappointing but I did learn that in a Skyhwak at least, you really have to screw up to get it to spin inadvertently.

Or get into a nasty shear or wake-upset situation... which is why I think fully-developed spins should still be demonstrated, instead of just "R and R".
 Less training accidents nowadays since they stopped doing that, but oddly enough, licensed pilots are still spinning in from the pattern, or after loss of control in IMC... maybe for some, there's just no hope.