The Leonard Annebula is an American
high-wing
A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes.
A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...
, single-seat
FAI Standard Class glider
Glider may refer to:
Aircraft and transport Aircraft
* Glider (aircraft), heavier-than-air aircraft primarily intended for unpowered flight
** Glider (sailplane), a rigid-winged glider aircraft with an undercarriage, used in the sport of glidin ...
designed by Bob Leonard of
Wichita, Kansas
Wichita ( ) is the largest city in the U.S. state of Kansas and the county seat of Sedgwick County, Kansas, Sedgwick County. As of the 2020 United States census, 2020 census, the population of the city was 397,532. The Wichita metro area had ...
, based on the
Hall Cherokee II
The Hall Cherokee II is an American high-wing, single seat glider that was designed by Stan Hall and introduced in 1956 as plans for amateur construction.Said, Bob: ''1983 Sailplane Directory, Soaring Magazine'', pages 8-9. Soaring Society of ...
.
[Said, Bob: ''1983 Sailplane Directory, ]Soaring Magazine
''SOARING'' is a magazine published monthly as a membership benefit of the Soaring Society of America. It was first published in 1937. The headquarters is in Hobbs, New Mexico. The magazine's article topics include safety issues and accounts of ind ...
'', page 36. Soaring Society of America, November 1983. USPS 499-920
Design and development
The Annebula design is derived from the Cherokee II, but while retaining the basic Cherokee structure, Leonard incorporated many changes and new features. The aircraft is built from wood and
fiberglass
Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cloth ...
, with
aircraft fabric covering
Aircraft fabric covering is a term used for both the material used and the process of covering aircraft open structures. It is also used for reinforcing closed plywood structures. The de Havilland Mosquito is an example of this technique, as ar ...
.
The Annebula uses a completely new single-
spar wing with Prue-type
trailing edge dive brakes. The
airfoil
An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine.
...
is a
NACA laminar flow
In fluid dynamics, laminar flow is characterized by fluid particles following smooth paths in layers, with each layer moving smoothly past the adjacent layers with little or no mixing. At low velocities, the fluid tends to flow without lateral mi ...
type of varying section over the span, starting at the
wing root as a NACA 64(3)-618, becoming a NACA 64(3)-615 by mid-span and then a NACA 4412 at the tip. The wing is constructed from
plywood
Plywood is a material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. It is an engineered wood from the family of manufactured ...
and fiberglass and is responsible for the Annebula's performance increase from the Cherokee II's 23:1
glide ratio to 31.5:1. The Annebula also has more span, wing loading and a higher
aspect ratio than the Cherokee II.
The
fuselage
The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...
was also extensively redesigned, with a new shaped nose, a new vertical fin with twice the area and a new fuselage shape aft of the wing. Landing gear is a monowheel.
Only one Annebula was built.
Operational history
Completed in 1967, the Annebula is registered as a US
experimental amateur-built.
By 1983 the sole example had flown over 700 hours and had been used to complete
Diamond badge
The International Gliding Commission (IGC) is the international governing body for the sport of gliding. It is governed by meetings of delegates from national gliding associations.
It is one of several Air Sport Commissions (ASC) of the Fédérati ...
distance and altitude flights. It also once held the
Kansas
Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the ...
state records for speed attained in , and triangles, goal distance, altitude and altitude gain. Aside from the designer himself, Leonard's three sons have also flown the aircraft.
Specifications (Annebula)
See also
References
{{reflist
1960s United States sailplanes
Aircraft first flown in 1967