Hi,
Beyond a straight and level stall, what other types of stalls exist? Ive been overwhelmed with different names and types of stalls, accelerated, spins, etc and im slightly confused as to under what circumstances and control inputs each one requires to occur.
Thanks

Let me start the beginnings of a list ...

(a) the wings level certification stall is that required to show compliance with the design standards by the OEM.

For light aircraft, refer FAR 23 and, in particular, FAA AC 23-8C (www.faa.gov/documentLibrary/media/Adviso...cular/AC%2023-8C.pdf - which provides a lot of guidance on how the FAA thinks flight test work should be done for light aircraft - very well worth while having a read through this AC). Main consideration is a slow approach to the stall (currently not faster than 1 kt/sec speed reduction in the relevant configuration) and idle power (although there is an alternative power setting permitted which doesn't change things significantly for most lighties) resulting in the approach to the stall's involving a descent.

While the specifics for the recovery have varied over the years with changes to the rule book, the basic idea is recover at the first sign of stall (usually an uncontrollable nose drop), get the angle of attack below stall and then, once definitely unstalled, increase power and complete the recovery. For lighties typical angle of attack for stall is in the mid-teens.

(b) the typical flight standards/training stall. This sort of approximates a certification stall but, in general, not terribly well.

Traditionally, the emphasis was on minimum loss of height during the stall and recovery. As a result the nature of the exercise was a bit different to what the OEM did and, on occasion, one gets surprising results. As a result of a number of accidents where the non-emphasis on reducing angle of attack as the immediate action was pivotal in the accident sequence, the emphasis has changed to align somewhat more with what the certification folks do.

(c) a variety of turning and accelerated (ie load factor somewhat above 1.0) stalls where things can get a bit more interesting, especially if one lets some sideslip get into the action ... good way to visit that wonderful activity called spinning .. Hence the emphasis on stopping the development of yawing motions during stall evolutions.

Lots of different terminology floating about the place but, basically, either turning or wings level with g applied intentionally by the pilot.

(d) a variant of the accelerated stall (often referred to as a dynamic stall to distinguish it from the usual quasi-static stall and probably not known by the majority of folks) occurs with very high pitch rates. If the pitch rate is high enough, as I recall up around 70 deg/sec or more, a spanwise vortex can develop along the forward section of the wing. This causes reattachment of the normal stall separating airflow and the wing then can increase angle of attack quite significantly before the vortex lets go and it finally stalls. Not something you will see In your typical lightie but a possible consideration with helicopters and, perhaps, very high performance fixed wing aircraft.

(e) a bit like (d), delta wings derive lift from a spanwise vortex located up near the leading edge and this is responsible for the very much higher angle of attack seen with delta wing aircraft manoeuvring. For these aircraft, the problem is not so much stalling (at a quite high angle of attack) but, rather, the massive increase in drag at the higher angles.

(f) contaminated wings. If the leading edge region either is damaged or contaminated (icing is the typical villain), pressure gradients can be affected adversely and a premature flow separation can occur, usually with very undesirable handling consequences. Especially for aircraft with leading edge slats only the merest of contamination is needed to provide undesirable flow consequences. Hence the admonition not to go flying with ice on the aircraft ....

(g) shock stall. This is another one you won't need to worry about for basic training but it is very relevant for higher performance aircraft. As the speed approaches the transonic regime, shocks develop In the airflow around the aircraft and, due to the sudden flow property changes across a shock, the flow can separate in a manner similar to a conventional stall. Unless design features are adopted to keep this animal under control, very undesirable handling results can follow. This was one of the problems faced by the early high speed flight researchers and TPs and resulted in the loss of many aircraft and crews before engineering understanding caught up with the speeds of which the then current high performance aircraft were capable.

(h) tail stall. This is a relative newcomer to the pilot knowledge base and, often, is associated with tailplane icing. As wing trailing edge flaps are extended, the changing downwash can get a bit too much for the ice-modified tailplane profile resulting in flow separation. Usually, the tailplane provides a moderate down force so the handling consequence typically is a fairly savage nosedown pitching motion. A number of accidents were related to this phenomenon until the boffins sorted out what was going on ....

I'll leave it for others to add some airs and variations to the theme ...

Wow, thanks for that! Ill have to sit down and have a solid research session.

Another question, I know its simple and may seem stupid but my mind seems to get really caught up on some basic principles. Say turning the ailerons into the bank. I understand that once we establish the angle of bank desired we can let go of the control column (in terms of roll motion) and solely use the elevator to not loose altitude. But im confused with the input. Does the amount of roll in the yoke we apply just define how quickly the aircraft will roll? Or do I continually have to apply more left/right aileron inputs to produce the required lift on the respective wing to produce the bank angle I want? So say if put x amount of aileron input in, it will only get me to y bank angle at which it will stay there because the aileron isnt providing enough lift to increase the bank angle any more. Its just something that hasnt really been explained to me from my studying and I havent made the connection intuitively when flying. Sorry if it seems like a stupid question.

once we establish the angle of bank desired we can let go of the control column (in terms of roll motion and solely use the elevator to not loose altitude.

For a conventional aeroplane, this might be just a tad simplistic, I think. An aeroplane is doing a whole bunch of things as it moves through the air and, indeed, the air generally is not steady so it further complicates the situation. If the pilot makes a single input, something usually results .. but then other things will happen depending on what the aeroplane is doing. Think further effect of controls as a for instance ..

When you crank in some aileron, you generate a roll input and the aeroplane starts to roll. There will be a short period of roll acceleration and then some resistance due to the rolling action .. for a specific input, after a short while you will then see something along the lines of a constant roll rate if you keep the aileron input constant. However, unless you are doing the other bits with the elevator and rudder (as might be necessary and appropriate) the aeroplane will be subject to yawing, extraneous rolling, and, perhaps, pitching motions. Hence you need to play with all the controls as might be required to achieve whatever motions you desire.

Some further reading (but suggest you boil the billy first before you sit down to reading away .. )

www.grc.nasa.gov/WWW/k-12/airplane/roll.html
www.flightlab.net/Flightlab.net/Download..._RollingDynamics.pdf

Plenty of net references around which saves your digging into the techo books at the library ...

A bit different, for example, with an A320 and similar .. where the aircraft electronic wizardry will hold the bank for you (as I understand - being a Boeing rather than an Airbus chap) if you let go of the stick.

Does the amount of roll in the yoke we apply just define how quickly the aircraft will roll?

Better to think of either aileron deflection (or, better, control input force - which is what you are sensing/assessing). The applied aileron deflection angle certainly will be the principal driver for roll rate.

Or do I continually have to apply more left/right aileron inputs to produce the required lift on the respective wing to produce the bank angle I want?

Generally, no, but keep in mind the earlier comments about the exercise not being able to be separated into individual bits and pieces .. not matter how you try to arrange it, the aeroplane will be doing lots of things and you have to influence these in a manner appropriate to achieving whatever it is you are seeking to do.

So say if put x amount of aileron input in, it will only get me to y bank angle at which it will stay there because the aileron isnt providing enough lift to increase the bank angle any more.

No .. doesn't quite work that way .. next time you are out flying, establish trimmed straight and level flight .. then crank in some aileron and hold it constant. Initially you will roll .. then the nose yaws, and a descent ensues ... into a spiral dive unless you do other necessary things to prevent that happening. However, you should be seeing a continuing rolling motion on top of the other bits and pieces.

Its just something that hasnt really been explained to me from my studying and I havent made the connection intuitively when flying.

Then give it a go by trying to make a single input and then holding it constant until you decide things have gone further than you might like ...

Sorry if it seems like a stupid question.

No such thing as a stupid question .. but it's certainly a bit silly not to ask the question if you aren't 100% sure what is going on. More to the point, sometimes, a bunch of other folks want to ask a similar question but hesitate for whatever reasons ... so your question might just help them out as well.