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For some of the V-speeds I'm not sure are they IAS or TAS. Here they are:

V-A - it depends on the weight of the aircraft and how much lift can it produce at a given weight so I GUESS it's IAS?

V-MC - IAS? Why? Because it's the minimum speed at which the rudder can be used to mantain directional control when an engine shuts down? At lower IAS than this there's not enough air over the rudder control surface in order to mantain directional control, right?

V-NE - IAS? Because above that speed the drag is to high for the aircraft and also the lift may increase too much and the wings and the aircraft may brake apart?

V-NO - Maximum structural cruising speed. Now this is what I don't understand. What does it mean maximum structural speed? Does it mean that the aircraft can't take drag above this speed? But what about V-NE then?It's higher than V-NO. And it's IAS, right?

Vx and Vy - Now this, it doesn't make sense to me if it is IAS. Vertical speeds (climbing speeds) depend on ground speed and thus TAS. When I climb at Vx or Vy as I get higher my IAS decreases and I have to lower the nose to mantain that IAS speed. So is it IAS or TAS? If it's IAS, why?

Short answer, all speeds are IAS.  The aircraft only knows IAS, TAS is just a mathematical number.

v a is maneuvrering full abrupt control can be given with out structural failuer...and yes i.a.s.. vmc minimum control speed  and is the speed where any increseing angle of attack or load will result in a stall..vne the red line exceeding vne is said to be the speed that u can expect structaual failure and again ias..vno is the is the speed you can fly BUT  not apply full abrupt control. ias again..all v speeds are I A S..the plane dont care how fast your ground speeds are ..it only cares how much load your putting on it..and airspeed is a direct result of that//now vx is the best angle of climb..its used on airports to clear obsticals trees hills etc..once cleared a pilot would for the most part resume a vy climb out..true airspeed is the ias corrected for temp. and alt.and pressure ..as u climb pressure and air dencity decreases ,,the prop is also becomming less  efficent..thats why you nose drops.. ground speed is not a factor when flyng vx or vy vx gives you the most alt for a given distance..vy..give you the most alt per unit of time..ground speed is no factor,,,a good example is if i  take off in a 15 knot head wind  the plane i fly..(im talking a full scale plane here)..i rotate at 80 knots into the wind ground speed is 55 but the plane thinks it going 80 dut to that headwind. ..if i do that in a tail wind and at a ias speed of 80 knots the ground speed is 95 ..but the plane thinks its only going 80..the wing only cares about whats going over it..hope all this helped.. regards 727 driver          quote author=Panther91 link=1219443769/0#0 date=1219443769]For some of the V-speeds I'm not sure are they IAS or TAS. Here they are:

V-A - it depends on the weight of the aircraft and how much lift can it produce at a given weight so I GUESS it's IAS?

V-MC - IAS? Why? Because it's the minimum speed at which the rudder can be used to mantain directional control when an engine shuts down? At lower IAS than this there's not enough air over the rudder control surface in order to mantain directional control, right?

V-NE - IAS? Because above that speed the drag is to high for the aircraft and also the lift may increase too much and the wings and the aircraft may brake apart?

V-NO - Maximum structural cruising speed. Now this is what I don't understand. What does it mean maximum structural speed? Does it mean that the aircraft can't take drag above this speed? But what about V-NE then?It's higher than V-NO. And it's IAS, right?

Vx and Vy - Now this, it doesn't make sense to me if it is IAS. Vertical speeds (climbing speeds) depend on ground speed and thus TAS. When I climb at Vx or Vy as I get higher my IAS decreases and I have to lower the nose to mantain that IAS speed. So is it IAS or TAS? If it's IAS, why?[/quote]