ORIGINAL: Ben-M
Fifteen years ago, a stall in the downwind turn destroyed my first RC plane - a glider - because I had no idea what I was doing. Recently I've had two incidents on the downwind turn on gusty days where airspeed has dropped low enough that a gust has stalled and then flipped the plane inverted.
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I note that a lot of the guys at the club don't seem to have the issue I do - I tend to fly circuits at half throttle and close to stall speed (or even glide them for fun), whereas these guys who fly WOT all the time never come across this issue because they're always well above the stall speed as they make that turn.
Maybe you should ask those members that don't have your problem. [sm=confused.gif]
Now except for use of a term that rather sets a level playing ground in discussions, there jus' ain't no critter such as "stall speed".
Like so many that speak of bank angle increases stall speed. Just so much ignorance which somehow became standard back before someone figured out how to recover from a spin. In subsonic convergent airflow the term "stall speed" has no foundation because the entire situation is a function of loading - critical angle-of-attack - where the airflow departs company with the low pressure side of a lifting surface caused by that surface being loaded into such angle from another source such as a horizontal stabilizer and elevator or such.
When you make a turn from an into-wind heading to a heading downwind, maintaining a constant airspeed, LEVEL altitude, then when you bank, the lift vector tilts to perpendicular to the machine's lateral axis. Without any change on your part, the total lift vector will be the same yet the vertical vector becomes less than that needed to sustain the established level flight. Therefore you add some up-elevator which increases the Angle of Attack (AOA) and if you were as you say, close to minimum speed and near max load factor, you could have increased beyond critical AOA and thus your machine would not be responding to your commands because there is no converging airflow over the wing.
One really needs some basic understanding of the basic Lift/Drag functions to really be in control of an airplane that is flying on the wing. I say the wing because so many now simply try to make airplanes into small bladed helicopters in disguise of an airplane.
Some model pilots don't understand the High-Speed stall. You can stall an airplane at any speed if you can pull the "Gs" needed to separate the airflow. Many a pilot has found that out for the one and only time allowed.
In a near max AOA pull, turbulent/convective air masses can kick your behind, causing a snap roll or such. There are a number of factors that will shove all the still-air theory believers into some strange positions. So if you just like to cruise low and slow, well it was once said, "Be careful out there, stay slow, stay low, and in the turns use lots of top rudder." Bad advice! [X(]