Tas Vs Lss ??

[theaviator2005]

Hi, just have a few questions that im discussing with a few guy's.

Were talking about TAS vs LSS (local speed of sound)

We do know that LSS is dependent on Temperature so with a decrease in temp we get a decrease in LSS. BUT!!!

How do they work agains each other TAS and LSS.

If one increases what happens to the other and vise verse!!!

[hetfield]

Scroll a bit further down in this forum....

[latetonite]

TAS has no direct relationschip to LSS.

[theaviator2005]

Ya thats what i was saying aswell that TAS does not have any direct relationship to LSS, but were discussing a question that was given at a Airline interview where it was asked: What happens to LSS or TAS if one increases or the other decreases?

Didnt make much sense to me as i do not believe that they are directly related.

Anyways
Thanks
;-)

[FLEXPWR]

If it is the relationship to the Mach number you're looking for, then there is a simple way to remember, here we go:

Chicken Tikka Massala :}

C for Calibrated (most aircraft today display CAS as IAS)
T for True airspeed (TAS)
M for Mach

At sea level, in ISA, all 3 should nearly be in the same spot, as well as Ground Speed if there is no wind.

As you gain altitude, C is less than T, and T is less than M.

3 possible scenarios (scenarii for the purists):

Constant CAS = TAS & Mach will increase with altitude
Constant TAS = CAS decreases and Mach increases with altitude
Constant Mach = CAS & TAS decrease with altitude

But I am probably off-topic, unless your question was about the Mach, and not the LSS.

Flex

[Poose]

Have a gander at the Local Speed of Sound thread. There's some good explanations on there. :ok: