DMyer

My Feedback: (2)

Here is one for you design gurus. On the new fuse I am building the thickest section (2 7/8") is right at the trailing edge of the wing. I understand this is supposed to create a bit of a wing fillit effect without the fillit. My question is.... in doing so... it makes the rear of the fuse much fatter and creates additional wet area. My first impression is that it would be good to pinch the rear of the fuse to reduce the wet area as well as to enhance the rearward thick section effect. Any opinions or additional thoughts?

PylonWorld

Take a look at the full scale airplanes that have been certified in the last few years, like the Cirrus SR-20/22 and Lancair Columbia (or Lancair 360, III, IV, or IV-P kit planes). Or the Diamond Katana Series. You will see that the widest point is at or near the trailing edge and that they have what is often referred to as "the Coke bottle" shape, or the "wasp-waisted" shape.

You have to be careful about how much and how quickly you pull the post trailing edge width down ... otherwise you will wind up with increased drag.

Another issue is straight surfaces. A decent wing design does not have any straight surfaces. Nor should a fuselage, although it is much less critical than a wing. This point can definitely be argued because some of the current top designs use straight surfaces. The question is complicated because of the small radius that must be used for the box fuselage. Although you may have a fuselage with theoretically laminar flow, the turbulence at the junction of the top and sides, or bottom and sides may cause enough of a disturbance that laminar flow goes out the window.

pwood

Hi Guys

In my opinion, the fuselage makes little difference.....

The prop wash messes up everything, the u/c, wheels and skid really get in the way.

I believe the wings have the most drag while producing lift, ie induced drag. I know form drag is increasing and induced drag is decreasing with increased speed. But in the corners at high g's the induced drag is high and a lot of speed is lost.

I always build the wings first and in this way "build them the best" and when i get onto the fus. i am always lazy/in a hurry/sloppy or whatever and never do as good a job. But the wings are good.

My logic about drag might be way off....any comments.