Something for the speed-to-fly page later on.

Known variables: ${\displaystyle a,b,c,V_{thermal},S_{g}lide}$ Unknown variable: ${\displaystyle V_{glide}}$

${\displaystyle P(v)=av^{2}+bv+c}$

${\displaystyle t_{total}=t_{glide}+t_{thermal}}$

${\displaystyle t_{glide}={\frac {S_{glide}}{v}}}$

${\displaystyle t_{thermal}={\frac {S_{thermal}}{V_{thermal}}}}$

Vanaf hier moet ik de -P consequent doorvoeren. Je gaat omhoog in de thermiek, dus minus de polaire klim je. ${\displaystyle S_{thermal}=P(v)*t_{glide}=-P(v)*{\frac {S_{glide}}{v}}}$

${\displaystyle t_{thermal}={\frac {-P(v)*{\frac {S_{glide}}{v}}}{V_{thermal}}}}$

${\displaystyle t_{total}={\frac {S_{glide}}{v}}+{\frac {-P(v)*{\frac {S_{glide}}{v}}}{V_{thermal}}}}$

${\displaystyle t_{total}=S_{glide}*({\frac {1}{v}}+{\frac {-P(v)*{\frac {1}{v}}}{V_{thermal}}})}$

We want to find the minimum of this formula. Since ${\displaystyle S_{glide}}$ only acts as a scaling factor, we can eliminate it:

${\displaystyle t_{total}={\frac {1}{v}}+{\frac {-P(v)*{\frac {1}{v}}}{V_{thermal}}}}$

${\displaystyle t_{total}={\frac {1}{v}}+{\frac {-P(v)}{v*V_{thermal}}}}$

${\displaystyle t_{total}={\frac {1}{v}}+{\frac {-(av^{2}+bv+c)}{v*V_{thermal}}}}$

${\displaystyle t_{total}={\frac {V_{thermal}}{v*V_{thermal}}}+{\frac {-(av^{2}+bv+c)}{v*V_{thermal}}}}$

${\displaystyle t_{total}={\frac {-(av^{2}+bv+c)+V_{thermal}}{v*V_{thermal}}}}$

${\displaystyle t_{total}={\frac {-a}{V_{thermal}}}*v+{\frac {-b}{V_{thermal}}}+{\frac {-c+V_{thermal}}{v*V_{thermal}}}}$

${\displaystyle t_{total}={\frac {-a}{V_{thermal}}}*v+{\frac {-b}{V_{thermal}}}+{\frac {-c+V_{thermal}}{V_{thermal}}}*{\frac {1}{v}}}$

${\displaystyle t_{total}'={\frac {-a}{V_{thermal}}}+{\frac {-c+V_{thermal}}{V_{thermal}}}*{\frac {-1}{v^{2}}}}$

${\displaystyle {\frac {-a}{V_{thermal}}}+{\frac {-c+V_{thermal}}{V_{thermal}}}*{\frac {-1}{v^{2}}}=0}$

${\displaystyle {\frac {-c+V_{thermal}}{V_{thermal}}}*{\frac {-1}{v^{2}}}={\frac {a}{V_{thermal}}}}$

${\displaystyle {\frac {-c+V_{thermal}}{V_{thermal}}}*{\frac {-1}{v^{2}}}={\frac {a}{V_{thermal}}}}$

${\displaystyle {\frac {-1}{v^{2}}}={\frac {a}{V_{thermal}}}*{\frac {V_{thermal}}{-c+V_{thermal}}}}$

${\displaystyle {\frac {1}{v^{2}}}={\frac {a}{c-V_{thermal}}}}$

${\displaystyle v^{2}={\frac {c-V_{thermal}}{a}}}$

${\displaystyle v={\sqrt {\frac {c-V_{thermal}}{a}}}}$