PylonWorld

Barry,

The fuselage design with the wide point at or near the wing trailing edge has been around for a long time. Even the Piper Cherokee series used it. The important part is not an expanding cross-section. The important part is stabilizing flow at the fuselage and wing junction. It is very hard to design fillets that adequately do the job. And of course Quickies don't have fillets at all. Neither do the Piper PA-28 (the Cherokee line including the [link=http://www.newpiper.com/fleet/arrow/index.asp?Model=Arrow]Arrow[/link], etc), the Mooney M20, the [link=http://www.raytheonaircraft.com/beechcraft/bonanza/bonanza_a36.shtml]Beechcraft Bonanza[/link] and most other low wing full scale aircraft.

Numerous (fullscale) Formula 1 aircraft (like the Mace Shark) have used the principal all the way back to the 40's. Many used a hybrid approach to keep the wetted area down also. The problem with the widest point at the rear of the wing is that the wetted area can become large enough to offset part of the drag reduction. That is why the coke bottle shape is important. On a Quickie, you don't want the high point at the rear of the fuselage along with the wide point because the cross-section will be larger than it needs to be.

The fullscale Lancair planes used the expanding width into a Coke bottle shape in the 80's. Check out the [link=http://www.lancair-kits.com/]Lancair Performance Kit Aircraft[/link] page for some fullscale applications of the principal. Lancair is pronounced Lance-Air.

A lot of research was published in the 60's and 70's on the wing/fuselage intersection. Many of the modern business jets use a junction that looks totally wrong from an intuition standpoint. Take a look at the [link=http://www.raytheonaircraft.com/beechcraft/premier/premier.shtml]Beechcraft Premier 1[/link]. The wing / fuselage intersection can cause as much as 1/4 of the total drag of the airframe. On the jets, the increased cross-section is a small price to pay for the drag reduction.