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UnknownTarget
07-07-2007, 12:59 PM
This is my secret shame here...I got my PPL a few months ago, but money restraints haven't let me fly since then, and my computer's been down so I haven't been able to sim to keep myself in practice for a similar length of time...coupled with a completely dizzying amount of summer boredom and TV watching (yes, kids, it really does make you forget things)...I've forgotten this...


In stalling, if your angle of attack increases, your stall speed also decreases, correct? (I.e. if you're flying at 10 degrees AoA you'll stall at 120 knts, while if you're flying at 40 AoA you'll stall at 20 knts?)

Thank you...that is all.

*Hides in his corner of shame*

KrasniyYastreb
07-07-2007, 01:24 PM
Uhhhhh NO. Your stall speed, IN LEVEL FLIGHT, is your stall speed and is not affected by the AoA. You stall speed will increase in a bank.

As you go slower, you need to fly at a higher AoA for the wing to generate enough lift to keep you airborne. Eventually, at a certain AoA (typically around 15-25 degrees, depending on a/c), the airflow around the ring starts to break down (detach) and the wing can't generate more lift, while the drag increases sharply. This is when you stall. So in level flight there will be one stall speed, corresponding to one AoA, at which you'll always stall.

But please, please, read up on this for yourself, and possibly put in some time with an instructor, before you go flying again. Considering some of the people on here, I would not trust my life to something I read on the forums.



Originally posted by UnknownTarget:
This is my secret shame here...I got my PPL a few months ago, but money restraints haven't let me fly since then, and my computer's been down so I haven't been able to sim to keep myself in practice for a similar length of time...coupled with a completely dizzying amount of summer boredom and TV watching (yes, kids, it really does make you forget things)...I've forgotten this...


In stalling, if your angle of attack increases, your stall speed also decreases, correct? (I.e. if you're flying at 10 degrees AoA you'll stall at 120 knts, while if you're flying at 40 AoA you'll stall at 20 knts?)

Thank you...that is all.

*Hides in his corner of shame*

UnknownTarget
07-07-2007, 01:34 PM
I didn't mean in level flight, but thanks for your reply http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif I do intend to go with an instructor again, once I reach college (flights there are $75/hour, as opposed to $130/hour here).

Kettenhunde
07-07-2007, 01:49 PM
Uhhhhh NO. Your stall speed, IN LEVEL FLIGHT, is your stall speed and is not affected by the AoA.

You are correct the indicated velocity does not change in level flight but remember that AoA is directly linked to CL. Stall occurs at a specific AoA.

In a turn our stall speed increases due to the load factor increase. As apparent weight goes up, we reach our critical AoA at a higher velocity.

All the best,

Crumpp

stalkervision
07-07-2007, 02:24 PM
trying out stalling in a real life plane makes one really apperciate why stalls are bad! In combat sims they are..."ah so what,big deal" not in real life! http://forums.ubi.com/groupee_common/emoticons/icon_eek.gif

UnknownTarget
07-07-2007, 02:28 PM
Hehe, yea. I trained in a DA-20 though, so stalls weren't that bad - the aircraft would pitch down a bit but you could recover almost instantly, as long as it wasn't too bad.

stalkervision
07-07-2007, 02:35 PM
Originally posted by UnknownTarget:
Hehe, yea. I trained in a DA-20 though, so stalls weren't that bad - the aircraft would pitch down a bit but you could recover almost instantly, as long as it wasn't too bad.

I was in a private plane as a passenger and it left my stomach 500 ft above me. Sort of like the feeling of a free falling elevator! http://forums.ubi.com/groupee_common/emoticons/icon_eek.gif http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

The-Pizza-Man
07-07-2007, 04:45 PM
It's a bit worrying that people can get PPL without knowing the basics of flight, that's not an attack on you UnknownTarget, just an observation of the system. Perhaps an aerobatic component should be included in the PPL syllabus.

UnknownTarget
07-07-2007, 09:47 PM
Oh, I knew it, and I knew it until a couple weeks ago. I just haven't flown in a long time so I've started to forget things (yes, even basic things - it's random what you forget sometimes). As an example - I've been using my spare keys for the past several days because I forgot where my real set is http://forums.ubi.com/groupee_common/emoticons/icon_razz.gif

Anyway, I actually kind of knew it in the first place, I just got myself confused.

It's required to know basics like that before you can get your PPL. Again, I just forgot. And yes, I do feel embarrassed/stupid about it - but that's why I asked instead of assuming I knew.

M_Gunz
07-07-2007, 10:32 PM
You can keep nosing up and adding power and go slower and slower but stay level.
Once you are at full power then you are trapped until you lose alt one way or another.
And you will be in control-reversal and on the edge of full stall....
So don't forget that when you think about -just- increasing AOA, it is possible just like it is
to be avoided, flying the back side of the level power curve. There's good GA sites that cover
it as delays in landing timing have gotten pilots into that more power and nose up pattern that's
led to many crashes.

UnknownTarget
07-07-2007, 10:37 PM
I do actually remember how to fly, heh...like I said, I just forgot this specific thing http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif I was a real whiz at low speed flying when I was getting my license, after my check ride my examiner said that I flew like a 250 hour pilot.

But thanks for your tips. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif As for one of my own; to any other new pilots that might be reading this, take the advice of someone who's been there - practice often, or at the very least go and fly a flight sim once in awhile, or you'll start forgetting things, and that can lead to embarrassing moments like these.

For practice, a good website that I used to get my PPL is www.exams4pilots.org (http://www.exams4pilots.org). Very informative, lots of questions, all of the graphics that are on the test, and it has all of the answers as well.

K_Freddie
07-08-2007, 05:48 AM
Many moons ago when I managed to go on my PPL (before buckazoids ran out), my instructor got nervous flying with me, as I wanted to practice my stall recovery toooooo much. It was a fairly safe plane to fly, so I had to force it into a stall, and recovery was simple enough within about 2000 ft. He'd get excited when I asked to go up again and do it all over, and over... what a prude. He didn't like my runway approach either, nose to the ground and flare at about 10ft and drop. Man! he freaked me out.

Anyway you'll find that stall speed is a function of aircraft (vector) direction speed and AoA. The higher your speed the higher the AoA can be. Your entry into a high-speed stall is faster, but recovery is a lot quicker, but you have more chance of over-correcting and spin out in the opposite direction, so be aware of this.

Didn't you get that big PPL book to study, before your first flight ??
http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif