Pylon mounted wings superior?

On Tuesday, February 11, 2014 11:56:19 AM UTC-6, Soartech wrote:
Wings with anhedral have been shown to be more efficient (L/D) than straight
wings. I can looks up the study if anyone needs to know more. This may be the
reason paragliders perform as well as they do despite large amounts of drag.

Please do. Might be amusing.

On Tuesday, February 11, 2014 12:15:43 PM UTC-6, wrote:
...Or possible it applies in some cases and not others.

Think you will find paragliders do have large drag, but such low speed as to make the horsepower consumed small. Think Paul MacCready and the Gossamer series of man powered planes. Most previous were cantilever, but he put wires out all over the place. Why? Lighter structure = lower flying speed = lower horsepower required. Horsepower is a cubic function of speed. Cut the flying speed in half, cut the horsepower to 1/8th. So you can afford a little higher drag if you knock the speed way down. Man powered flight is horespower limited. So is paraglider flight. They don't have to make much lift, and at low speed, all the risers don't make too much drag. Not much horsepower available from the low weight, either, so not much speed range.

On Tuesday, February 11, 2014 4:24:53 PM UTC-6, J. Nieuwenhuize wrote:
There are some other details at work; you gain lift, since now the wing is
actually lifting (no dip in the spanwise lift distribution anymore), so you
can actually shrink the wing area with a significant part of the wetted area increase.

Well, there is still a dip in the lift distribution. It is caused by the horizontal tail. If, of course, we are talking complete system, and not just wing. There is still a negative effect from the fuselage, but not NEARLY as big

On Tuesday, February 11, 2014 4:24:53 PM UTC-6, J. Nieuwenhuize wrote:
The pylon could be rather small, for a modern super-elliptic area
distribution (winglets), we now need a root chord of something like 24".
Given the fairly low forces on the pylon (save yaw, groundloop), the pylon
could be a lot smaller in chord and thickness.

The smaller you make the pylon and closer you get the load reacting points together, the higher the loads go. And, if you make the pylon too small, you lost all your volume for control connections. :-) Also, check the root chord on the AS-W27, V2, or even the Diana or Duckhawk. Think they are still 27 to 30 inches.

I also am not ready to buy into the need for anhedral for roll control if you have a pylon mounted wing. Weight of the wings, plus all the water carried in the wings, tends to make the fusleage and pilot a much smaller percentage of the mass of the flying machine. So, the center of mass is not starting as close to on the axis of the fuselage as you might think. What? The world doesn't revolve around the pilot? :-)

Good thoughts. Keep them coming.

Steve