Originally Posted by
lzakplt
Why can't a conventionally configured airplane have a lifting tail, because your Jeppeson private pilot manual said so?
Geeze, if I did not know any better, that sounds a bit disrespectful.
I don't know you, you don't know me, or my education and experience. So instead of an off the cuff remark like that, how about explaining how what I posted is wrong?
"This is generally true but you have to distinguish between the center of lift as being that of the forward main wing, or taken as a combination of the main wing plus the aft-mounted tail. If the center of lift of the
sum of the lifting surfaces is behind the center of gravity, then stability is maintained despite the possibility CG is behind the center of lift of the fore-mounted main wing.
As far as Caravan is concerned, what the tail does and when is beyond the scope of information currently available. A quick look at the approved CG range suggests it may have an uploaded tail at certain times. But one cannot know without access to tests and specific data. As far as I know the stability data for Caravan is not publicly accessible. Yesterday 08:38 PM"
The center of lift is always just that, the center of lift. I am not sure how you can include the stabilizer in the picture - the center of lift will show up somewhere about the MAC of the wing. I would LOVE to know how you can look at cg range and come up with the remark that at some point the *stabilizer* is responsible for some of the total lift force required.
Let me ask, do we agree that most (I say all) of the time, the stab is producing a down force? If yes, and you think at some point it produces a load supporting up lift, what happens right at the point where it transitions? Explain what you think stability will be like at that point? Or, what stability will be like if at any point in the flight will be like if the stab is actually lifting in the same direction of the wing? That would be one tough airplane to fly. I would think it would need a computer.
Your concepts of stability and control are far different than mine, and I am just asking for your explanation.
And no, thanks, I did not pick that up in a Jep Private pilot course, I got it by other means.