How does stall speed vary with c of g

Plus a little more back pressure on the yoke to hold altitude due to the loss of vertical component of the lift from the banked wings. Your email address will not be published. Notify me of follow-up comments by email. Notify me of new posts by email. Keep those questions coming! Share this: Facebook. The most common danger from ice in New Zealand is its formation on the wings and tailplane of aeroplanes parked overnight, and sometimes it is so thin and clear that it is hard to detect.

No attempt should ever be made to take off with ice or frost on the wings or tailplane, because of its effects on the smooth airflow and the resulting increase in stall speed — which cannot be quantified and may be well above the normal rotate speed. Explaining this effect is one reason why advanced stalling is often left until after solo circuits and steep turns; before first solo the explanation is kept as simple as possible.

For an aeroplane, this is often referred to as apparent weight, or G, and this increase in apparent weight increases the requirement for lift, and increases the stall speed.

If the aeroplane could climb vertically there would be no requirement for lift at all. So when thrust is inclined upwards, it decreases the requirement for lift and reduces the stalling speed. In addition, the slipstream generated by having power on increases the speed of the airflow and modifies the angle of attack generally decreasing it over the inboard sections of the wing.

The increased airspeed increases the lift and reduces the aeroplane's stall speed, and the modified angle of attack increases the nose-high attitude see Figure 1. Figure 1 When thrust is inclined upwards, it decreases the requirement for lift and reduces the stalling speed. Flap increases lift and therefore the stalling speed is reduced.

However, flap also changes the shape of the wing, and this results in a lower nose attitude at the stall. The point at which drag rapidly increases varies with aeroplane and flap type, but this is usually at the flap setting recommended for a soft-field take-off.

Slats and slots allow the aircraft to operate at a higher C L lift coefficient max, re-energising the boundary layer and therefore stall speed is reduced. If, at the stall, the aeroplane starts a slight roll, using aileron to stop the roll a natural tendency will increase the angle of attack on the down-going wing.

This decreases the lift even further and increases the drag, continuing the roll — not stopping it. This is the reason for maintaining ailerons neutral in the initial stall recovery and using rudder to keep the aeroplane straight on the reference point.

Situational awareness considers not only the position of the aeroplane three dimensionally within the training area but also the warning symptoms of the approaching stall, and awareness of the flight phase — power reduced but attempting to maintain level flight. Carry out a minimum of one degree, or two degree, clearing turns, to ensure other traffic will not result in conflict.

Temperatures and pressures normal, mixture rich, fuel sufficient and on fullest tank, fuel pump on. The regular turns and steeper than normal nose attitudes could lead to some disorientation. Make sure the student has time between stalls to orientate themselves. This exercise may produce some discomfort in the student, especially if your aeroplane type has a tendency to wing drop.

Reassure the student that this is not a dangerous exercise when conducted above feet — as you will be doing. Tell the student that if they feel uncomfortable at any point, they should say so. The aeroplane can then be flown level until they feel comfortable to continue. HASELL checks are completed and a prominent outside reference point on which to keep straight is nominated.

Start by carrying out a basic stall entry and recovery as a reference to compare the effect power and flap has on the stall. In particular, the student should identify the attitude, speed and recovery references.

As the nose will want to yaw and pitch down, keep straight with rudder and hold the altitude with increasing backpressure. Lift must be increased to balance the increased downwards force. CG movement due to the direction in which the undercarriage extends will have an insignificant influence on stall speed. By far the greater influence is the increased profile drag of the gear when it is extended.

When establishing V CLMAX the engines must be at zero thrust and it is assumed that the weight of the aircraft is entirely supported by lift. If thrust is applied close to the stall, the nose high. Aircraft with propellers will have an additional effect caused by the propeller slipstream. The most important factors affecting this relationship are engine type propeller or jet , thrust to weight ratio and inclination of the thrust vector at C LMAX.

Figure 7. The slipstream velocity behind the propeller is greater than the free stream flow, depending on the thrust developed. Thus, when the propeller aeroplane is at low airspeeds and high power, the dynamic pressure within the propeller slipstream is much greater than that outside and this generates much more lift than at zero thrust. The lift of the aeroplane at a given angle of attack and airspeed will be greatly affected.

This will increase the apparent weight. As apparent weight is increased stall speed will increase. All other parameters are fixed, in this situation. This is a loaded question as it can possibly deal with aircraft stability, maneuverability and controllability. Take a look at the picture above. For the forces to balance, there has to be one force in the opposite direction in between two other forces.

CG center of gravity and T tail-down force are used to oppose CL center of lift. The distance between CG and CL and CL and T are important as they provide the characteristics of stability, maneuverability and controllability.

A stall occurs when the wings reaches its critical angle of attack. At greater weights, the wings will have to produce greater lift. The T force is a weight that has to be countered by CL. Now, as pilots, we don't talk about CL moving but changing CG. As a result, an aft CG reduces stall speeds. If CL is forward of CG for an airplane like what is pictured above, the aircraft will be unstable. There are two opposing forces on one side helping the other force cause a rotation.

Try it. Take a pencil between your two hands.