Author's Gee Bee R2 Profile Design Block 1

The aim of this design was to create an easy to build relaxing flyer with reasonable aerobatic performance.
A flat bottomed Clark Y airfoil was used. The design has a semi scale outline with a detachable wing with no dihedral.
This design flew well in light winds but was not so good in moderate or strong winds. Aerobatic performance was poor. With a 4S battery pack aerobatic performance improved slightly.
Take off roll was short and when landing would float a considerable distance after flaring.
The low aspect ratio wing produced a lot of induced drag and due to sloppy building one wing panel had slightly more incidence than the other resulting in trim being required for level flight.
Also the increased incidence caused the left wing to stall before the right. Due to the large surface area of the fuselage, the stall would result in a semi knife edge flight path. Recovery was only possible by rolling inverted and pulling out or rolling left until the aircraft was upright again. Due to the slow roll rate this was a risky manouevre if this occcured at a low altitude.
This model was  badly damaged after such an incident and was scrapped. The Block 2 version of this design has a number of improvements and will be added to the User Designs page.

Specifications

Wing Span 48 inches
Wing Area 652 sq. inches
Aspect Ratio 3.42
Airfoil Clark Y

Construction material Balsa and Ply
Covering SolarFilm
Battery 3S 2200mah - 4S 2200mah
Propeller 13X8 APC E
ESC 40 Amp
4 Channel Radio

Motor Turnigy G25 Brushless Outrunner 870 KV

Watt Meter Tests
300 w on 3S - 370 w max at start
600 w on 4S - 660 w max at start

Empty Weight excluding battery 1.6kg


Winfoil Design File