RC India

General Topics => RC Maneuvers and Skills => Topic started by: vishalrao on February 28, 2013, 10:42:34 AM



Title: Recovering from Stalls
Post by: vishalrao on February 28, 2013, 10:42:34 AM
Just came across this interesting video where the author describes about what causes stalls and how to recover from them. Strangely, the only thing that the author suggests to recover from a stall is to release the elevator sticks! Although I have never recovered from a stall yet, I'm finding this advice difficult to digest and experiment on my plane. Any expert inputs are welcome.

http://www.rcpowers.com/community/threads/beginners-flight-school-stalls.4056/


Title: Re: Recovering from Stalls
Post by: asinghatiya on February 28, 2013, 11:09:23 AM
to recover from a stall is to release the elevator sticks!
http://www.rcpowers.com/community/threads/beginners-flight-school-stalls.4056/


Absolutely its the only way to recover Stall! I tried manytimes on models too! Elevator is the only reson when applied at lower speeds push the aircraft to enter a stall!! Releasing it will provide the threshold speed to recover and keep the model floating!! Try it in Filght Simulator with a Boeing.


Title: Re: Recovering from Stalls
Post by: vishalrao on February 28, 2013, 11:14:31 AM
Thank you asinghatiya sir! I had forgotten about my simulator :)

What if there isn't sufficient altitude and the plane goes in a spin? I guess it'll be too late for the plane to recover by itself.


Title: Re: Recovering from Stalls
Post by: asinghatiya on February 28, 2013, 11:17:11 AM
What if there isn't sufficient altitude and the plane goes in a spin?

Thanks!!

 >:D Remember the GOD you beleive and pray that your eject seat is working properly!!


Title: Re: Recovering from Stalls
Post by: vishalrao on February 28, 2013, 11:20:44 AM
 :giggle: I'm lot relieved now as there's nothing much I can do for stalls at low altitudes except to actually prevent the stall from coming  ;D


Title: Re: Recovering from Stalls
Post by: shobhit17 on November 11, 2013, 10:26:16 PM
well... the aerodynamics of stall are not so simple.... Stall is a state of flight when the wing is unable to develop enough lifting force to suport the weight of the plane and the plane simply falls from the sky.  A well balanced plane will always have its CG slightly ahead of the actual required CG position.  This has two advantages....
1.  The plane remains controlable as a heavier nose makes the plane more stable and helps controlability.  An aft CG makes the plane unstable and thus at times uncontrolable.  Hoever there are limits of how heavy the nose should be.
2.  Now whenever you have an engine failure or experience a stall..... the heavier nose plane will have a natural tendency to go nose down and in a dive.  Thus often recovering from the stall all by itself.

NOW...
To recover from a stall... put the plane in a slight dive to build up speed over the basic stalling speed (Basic Stalling Speed is the speed at which a wing is unable to produce sufficient lifting force to sustain the plane in a straight and level flight and the plane thus starts to loose height rapidly.  This speed can be reached in straight and level flight in case the throttle is reduced very low and the plane continues to fly straight and level, thus to maintain the required amount of lift its Angle of Attack will need to be increased and at a particular point it will cross the stalling angle.  This speed at which is state occurs is called as the basic stalling speed).  As the speed builds up in the dive increase throttle and use the elevator to recover from the dive.

OK.... A stall can take place even at higher speeds.... i.e. during turns and High G manouvers.  as a thumb rule in a 60% turn increases the Basic Stalling Speed by 100 %.  i.e. a plane stalls at twice the speed if you are doing a turn with 60% bank in a level flight.  In high G manouvers the plane can be stalled almost anytime.... recovery actions are to get wings level, relax the up elevator to reduce the G loading.... if required put the plane in a shallow dive.  The plane will itself recover from the stalled state.

NOW.... increase power and take control of the plane again.

In case flying gas / turbine engines.... you got to be very carefull during stalls as the engine too might be forced to stall (something called as an engine surge in jet engines).  In thus condition the engine temperature increases rapidly due to unsteady airflow through the engine and may cause melting of engine parts..... causing permenant damage to the engines.

 So never do anything funny close to ground.... MUST always have sufficient sky between the plane and the ground.. for it to recover and continue flying....

Aerodynamics helps...... Happy Flying