# Calculating landing distance for Flight

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1. Nov 22, 2014

### praveenpandiyan

1. The problem statement, all variables and given/known data
An a/c has an approach speed of45 m/s with descent angle of 7.1 deg. if the a/c load factor is 1.2 and constant deceleration at touch down is .25g (g=9.81).its total landing distance approx over a 15m high obstacle is

2. Relevant equations

R=v/g(n-1)
Sa=(h-hf)/tan( teta)
Sf=Rsin(teta)
hf=R(1-cos(teta)
Sg=v2m/(2*F)
S=Sa+Sf+Sg
3. The attempt at a solution
well i have found value for approach and flare distance.but for ground roll im lacking mass to consider for calculation or do i miss smeting?.. any suggestion wld be helpfull.

2. Nov 23, 2014

### PhanthomJay

in your work-energy equation for Sg, m/F per Newton 2 is given! Or use the kinematic equations instead.

3. Nov 23, 2014

### NTW

You have an initial horizontal velocity at touchdown and the deceleration. That's enough. For ground roll, and leaving aside air resistance, mass doesn't matter.

4. Nov 23, 2014

### praveenpandiyan

yeah.i see it now,its a simple force eqn. thanks all