Calculating landing distance for Flight

[praveenpandiyan]

Homework Statement

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

Homework Equations

R=v/g(n-1)
Sa=(h-hf)/tan( teta)
Sf=Rsin(teta)
hf=R(1-cos(teta)
Sg=v2m/(2*F)
R-radius,hf-flare height,Sa-approach dist,Sf-flare distance,Sg-ground roll
S=Sa+Sf+Sg

The Attempt at a Solution

well i have found value for approach and flare distance.but for ground roll I am lacking mass to consider for calculation or do i miss smeting?.. any suggestion wld be helpfull.[/B]

 

[PhanthomJay]

Homework Statement

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

Homework Equations

R=v/g(n-1)
Sa=(h-hf)/tan( teta)
Sf=Rsin(teta)
hf=R(1-cos(teta)
Sg=v2m/(2*F)
R-radius,hf-flare height,Sa-approach dist,Sf-flare distance,Sg-ground roll
S=Sa+Sf+Sg

The Attempt at a Solution

well i have found value for approach and flare distance.but for ground roll I am lacking mass to consider for calculation or do i miss smeting?.. any suggestion wld be helpfull.[/B]

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

 

[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.

 

[praveenpandiyan]

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