IAS, Drag , Density, TAS
Hello all..
I have a question regarding the relationship between IAS , Drag and Air Density (and also TAS I suppose) after reading the following statement in the JAR Oxford Performance manual...
"For given Indicated Airspeeds , the total Drag does not change with density (pressure or temperature) at a given mass"
> If an airplane (lets say a fixed pitch piston prop) at say 2300rpm gets an IAS of 90 kts. at 2000 feet , will it get the same IAS at 8000 feet. Or in order to maintain the 90 kt (IAS) at 8000 feet will a higher setting be required due to the reduced density ?
> And if the same setting is maintained at a higher altitude , wont the drag decrease due to the decreased air density ? Or does the statement mean to say that IAS will reduce at a higher altitude (drag would also reduce), and in order to get back the IAS you would increase power (& thrust) hence also increasing drag and getting it back to its original value.
>Does the statement apply to props and jets ?
..I know they may be silly questions, but ive been thinking about the statement and cant quite entirely work it out.. thanks in advance..