Relationship between speeds?

[99jolegg]

Hi,

Does anybody have a rule of thumb or know of a place that puts simply the relationship between EAS / RAS / CAS / TAS / Mach Number...specifically when climbing / descending through an inversion or through an isothermal layer?

Thanks

[nick14]

Have you heard of the Chicken Tikka Masala graph?

I cannot find one on the web but Im sure there is one about. In the meantime look here:

https://www.pprune.org/archive/index.php/t-9761.html

Essentially from what I can remember its to do with the change in temp and pressure. As you climb temp and pressure reduce, so overall the density reduces from that you can deduce that climbing at a constant CAS will give you increasing TAS and Mach number. Constant TAS will give you reducing CAS and increasing Mach number and constant mach number will give you reducing CAS and TAS.

In an isothermal layer (above Tropopause) then the temp is constant hence the name. As Mach number is wholly based on TAS and Temp then mach number is constant with constant TAS and Vice Versa.

Nick

[99jolegg]

Thanks, when everything is constant it's simple. It's when you involve isothermals / inversions that I'm spending too long trying to figure out which way it goes.

Never heard of a Chicken Tikka Masala graph either!