#separator:tab #html:false Units and Conversion to metres from Nm, Feet and Kilometres.1Nm = 1852 Metres 3.28 Feet = 1Metres 1Km = 1000 Metres SpeedSpeed = the rate of change of distance Velocity = the rate of change of distance in a specific direction Horizontal Speed = Measured in Knots (kt) 1kt = 1 Nautical Mile Vertical speed = Measured in feet per minute (fpm) Converting speed into metres from knotsx 1852 and then divided by 3600 - As an approximate guide half knots = the metres per second - m/s = 0.5144 x knots Converting speed from metres to knotsdivide by 1852 x by 3600 - m x 1.944 - double the metres to find knots ( Approximate) Rates of climb and decentTo convert between Metres and feet to feet per minute they both need time to be in seconds and metres to feet 1m/s = 60 (sec) x 3.28fpm (1 metre in feet) =196.8metres (Q) What is 600fpm rate of decent expressed in metres? (A) 600fpm / 196.8 = 3.05m/s AccelerationAcceleration = The rate of change in Velocity An aircraft is accelerating if: - a speed is changing along a straight flight path - speed is constant but the direction changes - or both simultaneously A force is needed to accelerate, the higher the force the greater the acceleration. MassMass = the quantity of matter a body possesses 1kg = 2.205lb 1lb = 0.454kg Momentum- Product of an objects mass and velocity ForceAn object in motion will stay in motion unless acted upon by a force WeightWeight = the force a mass exerts in a gravitational field W= m x g Gravitational Acceleration = 9.81 or 10m/s Energy- Measured in Joules - 2 examples are kinetic energy and Pressure energy ke = 1/2 mass x V squared Pressure energy = the energy contained in millions of molecules that make up the volume of air they are constantly moving and colliding and transferring momentum from one another. the result is experienced as static pressure. - Energy is conserved: If kinetic energy increased pressure energy must decrease. Frames of referenceEither - The aircraft has speed relative to air or - The air has speed relative to the aircraft Depending on the reference it's either the mass of the craft or the mass of the air flowing past it that posseses the kinetic energy. a) for an aircraft in flight it is useful to consider the air mass to be moving and possesses kinetic energy b) for an aircraft landing it is useful to consider the aircraft having relative speed WorkWork = When energy is converted from one form to another Work = force x distance (Q) Find the work done by the engines with a total of 50000N in thrust travelling at 300kt (150m/s) in 1 minute/ (A) Start by finding how much the aircraft travels in a minute/ 1 minute = 60 seconds 150m/s x 60 = 9000m 50,000 N x 9000m = 450 million joules PowerPower = the rate of doing work Newtons first LawA body will remain at rest or in motion unless acted upon by a force. Newtons second LawThe acceleration of a body in a straight line is proportional to the force applied and inversely proportional to the mass of the body. Newtons Third LawEvery action has an equal and opposite reaction.