Tip Stall
#27
ORIGINAL: Bozarth
Oh, but it does. A tad shy of 2 g's at 60 degrees of bank and you will descend. A tad too much pull (more than 2 g's) at 60 degrees and you will climb. Trigonometry at it's finest.
Kurt
ORIGINAL: essyou35
?? G force doesn't make you maintain level flight. As for the rest of your post no idea what you are saying.
?? G force doesn't make you maintain level flight. As for the rest of your post no idea what you are saying.
Oh, but it does. A tad shy of 2 g's at 60 degrees of bank and you will descend. A tad too much pull (more than 2 g's) at 60 degrees and you will climb. Trigonometry at it's finest.
Kurt
It's all about the forces on the aircraft - ALL OF THEM.
#29
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From: WA, NEW ZEALAND
Hi Gerryndennis,
I wasn't replying to you so much as just adding what I know (or think I know) to the thread. It's a very interesting topic. Thanks for your reply, it goes to show how little I know.
Cheers.
I wasn't replying to you so much as just adding what I know (or think I know) to the thread. It's a very interesting topic. Thanks for your reply, it goes to show how little I know.
Cheers.
#31

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From: Christchurch, NEW ZEALAND
ORIGINAL: FLYMAD
Could someone tell me how to tell the difference between an asymmetric stall and a tip stall. What are the visible differences.
Could someone tell me how to tell the difference between an asymmetric stall and a tip stall. What are the visible differences.
In an asymmetric stall (stall developing from the tip) the wing will drop and a spin may develop if no correction is made... much more violently and quickly.
In an asymmetric stall (stall developing from the root) aileron (gentle) will at least reduce the roll and may be sufficient to prevent the wing drop.
In an asymmetric stall (stall developing from the tip) aileron will make the wing drop worse.... much worse.
Flymad you're post said 'in reply to... me' in the bottom right hand corner, which is why I wondered.
Dave H
#32

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From: Christchurch, NEW ZEALAND
ORIGINAL: Rob2160
The wisest words written in this thread, . Yes this was the most fundamental concept we would teach aerobatic students.. Your elevator is an angle of attack control device.. the wing always stalls at the same critical angle and therefore the elevator joystick (RC or fullsize) will be in the same position each time you stall.. if stall is encountered, you only need a few mm forward stick to unstall..
Very refreshing to see someone else say this.. Ahh.. New Zealander... Ex RNZAF?
ORIGINAL: gerryndennis
My advice to all modellers is stall your model lots,<span style=''color: rgb(255, 0, 0);''>get used to where the elevator stick is when it stalls. Every time you put the stick in that position your model will stall</span>. If you find yourself turning final low and slow or making a tight turn and you notice that the Angle of Attack (elevator) stick is near the stall position then be aware that you are near the stall. Speed or angles (bank or climb or descent) are irrelevant.
Not quite 100% true in theory but close enough in practice.
Dave H
My advice to all modellers is stall your model lots,<span style=''color: rgb(255, 0, 0);''>get used to where the elevator stick is when it stalls. Every time you put the stick in that position your model will stall</span>. If you find yourself turning final low and slow or making a tight turn and you notice that the Angle of Attack (elevator) stick is near the stall position then be aware that you are near the stall. Speed or angles (bank or climb or descent) are irrelevant.
Not quite 100% true in theory but close enough in practice.
Dave H
Very refreshing to see someone else say this.. Ahh.. New Zealander... Ex RNZAF?
I agree totally with your 'elevator is a (the?) angle of attack control device' concept but I wasn't allowed to call it the 'joy stick'. Sort of a 'this is my rifle, this is my gun, this is for shooting, this is for fun' argument for using correct terminology (military's funny like that).
My first flight with a civilian instructor included 30 minutes of basic stall instruction as part of the type rating (light twin) and then a demo of the recovery. When it was my turn I checked forward, increased power, and climbed away. 'What the hell was that' he yelled 'you'll re stall if you recover like that, you need to go for speed'.
I pointed out that if speed was the important thing then what was the point of the last 20 minutes (that I was paying for) demonstrating all the (angle of attack related) stall symptoms. And how would his recovery work at 300' turning finals from a circling approach, you guessed it his speed based recovery took 300', mine 30' (yeah I know but it was my first touch of the stick, sorry sir, control wheel).
To give him his due he did accept that he had been teaching it all wrong, especially after I showed him some accelerated stall recoveries (2G /60 bank, 90 bank and about 30 kts in a wing over). Doubt that he's been able to convince CAA to change the syllabus though.
Where do you teach aero's?
Dave H
#33
ORIGINAL: essyou35
?? G force doesn't make you maintain level flight. As for the rest of your post no idea what you are saying.
?? G force doesn't make you maintain level flight. As for the rest of your post no idea what you are saying.
To produce lift in subsonic convergence airflow, one has to provide the airflow with needed pressure variations to attain the needed forces. Given a wing in a 60° bank relative to earth, at I G loading will be 1 G short of the required aerodynamic force required to maintain level flight.
Should you not understand these basic lift/drag/etc. aerodynamic truths, I certainly agree that you would have absolutely NO IDEA of what I was/am saying.
#34
ORIGINAL: Rob2160
The aircraft will NEVER stall by itself..... A stall will never just Happen to you.. It is a result of what you are doing wtih the elevator. any aircraft will stall if you apply too much elevator..
Depending on a number of factors (control throw, CofG, wing shape, elevator size etc) the elevator position for the stall may be 30% deflection or it may be 90% deflection, but for a given aircraft, and without changing the CofG, the elevator position will always be the same .
The tapered wings will usually stall at the tips first,
When I hear people say.. "The plane just stalled on me, the true answer is.. NO.. you stalled the airplane by using too much elevator... you just may not have realised you were doing it"
The aircraft will NEVER stall by itself..... A stall will never just Happen to you.. It is a result of what you are doing wtih the elevator. any aircraft will stall if you apply too much elevator..
Depending on a number of factors (control throw, CofG, wing shape, elevator size etc) the elevator position for the stall may be 30% deflection or it may be 90% deflection, but for a given aircraft, and without changing the CofG, the elevator position will always be the same .
The tapered wings will usually stall at the tips first,
When I hear people say.. "The plane just stalled on me, the true answer is.. NO.. you stalled the airplane by using too much elevator... you just may not have realised you were doing it"
#35
ORIGINAL: Hossfly
Nothing ''makes'' one maintain level flight. OTOH, should one (pilot) decide to maintain level flight then that someone has to follow the laws of nature such as lift equal to weight.
To produce lift in subsonic convergence airflow, one has to provide the airflow with needed pressure variations to attain the needed forces. Given a wing in a 60° bank relative to earth, at I G loading will be 1 G short of the required aerodynamic force required to maintain level flight.
Should you not understand these basic lift/drag/etc. aerodynamic truths, I certainly agree that you would have absolutely NO IDEA of what I was/am saying.
ORIGINAL: essyou35
?? G force doesn't make you maintain level flight. As for the rest of your post no idea what you are saying.
?? G force doesn't make you maintain level flight. As for the rest of your post no idea what you are saying.
To produce lift in subsonic convergence airflow, one has to provide the airflow with needed pressure variations to attain the needed forces. Given a wing in a 60° bank relative to earth, at I G loading will be 1 G short of the required aerodynamic force required to maintain level flight.
Should you not understand these basic lift/drag/etc. aerodynamic truths, I certainly agree that you would have absolutely NO IDEA of what I was/am saying.
Bob
#36
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From: BILOXI Mississippi
After fooling about with aviation for some time now. Full scale and flying models. I have never encountered a beginner wanting to know all the ins and outs of aero dynamics. Most new folks, also known as beginners know if the tip of the wing hits the big ball, also know as the earth, it is a bad thing. Now I do think the beginners that come to this section of RCU do enjoy all this going ons about what make one of these things fly. What I have found out is some pilots are better flyer because of the planes they fly. I also discovered who is the best pilots depends on who is doing the telling. Like one of the new dudes told me yesterday on the flight line. "Mr Jerry, some of these people are real serious about all this"





