The Ligeti Stratos joined/box wing aircraft seems worthy of more attention than it gets. Can we discuss this design?
It is said to have a L/D of ~20:1. Its joined-wing configuration brings to mind some of the box-wing discussion noted in Hoerner's Fluid Dynamic Drag and Fluid Dynamic Lift books, where he cites remarkable reduction in induced drag when biplane wings are joined at their tips by a foil shape.
Given the acute joint angles of the Stratos wing joint (more interference drag than necessary), coupled with the drag of a fixed bicycle landing gear, Stratos may have potential for improvement with even less overall drag. In other words, if the box joint at the wingtips were radiused to elimated the draggy interior angles, and the landing gear were retracted, this plane might have an even better L/D. As reported years ago, the Stratos got 80+ mpg in original (presumably draggier than necessary) configuration.
Reportedly, the plane weighs ~172 lbs. empty, about the same as a Cri Cri. Since planes are effectively priced by the pound, this and the small (garage-able) size would seem an ideal homebuilt project. It also reportedly needs a takeoff roll of ~300 feet, making it handy for very small airfields.
There is an open-source design group.
So, how do other posters view this aircraft, pro or con?
It is said to have a L/D of ~20:1. Its joined-wing configuration brings to mind some of the box-wing discussion noted in Hoerner's Fluid Dynamic Drag and Fluid Dynamic Lift books, where he cites remarkable reduction in induced drag when biplane wings are joined at their tips by a foil shape.
Given the acute joint angles of the Stratos wing joint (more interference drag than necessary), coupled with the drag of a fixed bicycle landing gear, Stratos may have potential for improvement with even less overall drag. In other words, if the box joint at the wingtips were radiused to elimated the draggy interior angles, and the landing gear were retracted, this plane might have an even better L/D. As reported years ago, the Stratos got 80+ mpg in original (presumably draggier than necessary) configuration.
Reportedly, the plane weighs ~172 lbs. empty, about the same as a Cri Cri. Since planes are effectively priced by the pound, this and the small (garage-able) size would seem an ideal homebuilt project. It also reportedly needs a takeoff roll of ~300 feet, making it handy for very small airfields.
There is an open-source design group.
So, how do other posters view this aircraft, pro or con?
