Nice answer Chicken6, but I still have a question about it
<font face="Verdana, Arial, Helvetica" size="2">"Ah, but if we go faster by lowering the nose a bit we reduce the induced drag don't we, this compensates for the increased parasite drag. Well spotted though."</font>
During a max range glide, the AoA remains constant so as to maintain the best L/D ratio, correct? If so, the induced drag
cannot decrease, or at least that is my understanding of it. (Incidentally, the
nose attitude is
identical for a best range glide at a heavy acft weight as at a light acft weight, only the EAS changes.)
Also, we don't actually go faster
because we lower the nose (this would imply we are no longer maintaining the best L/D ratio), we go faster because a greater Thrust Component of Weight (TCW) is acting along our flightpath.
So, my question still stands (unless I am missing some logic here, which is possible
):
<font face="Verdana, Arial, Helvetica" size="2">
If the aircraft is heavy, it will need to go faster, and if it is lighter it will go slower, but either way it will follow the same glide path to the same spot.
</font>
"if we are going faster, then we are producing more parasite drag, so why does our angle remain constant?".
And your point about the Weight vector is a valid, thankyou for pointing it out to me !
Cheers,
Grade 3
(edited to fix a formatting error)
[This message has been edited by grade_3 (edited 24 February 2001).]