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HORNET - WOODEN ULTRALIGHT MOTORISED SAILPLANE

HORNET is an ultralight sailplane optionally equipped with retractable motorplant for selflaunching.
Glide angle: aprox 1:23
Materials: plywood, spruce, styrofoam, carbon rods
Similar existing types: ALPIN TST-3


SPECIFICATIONS for HORNET UL-SAILPLANE

wing span	11 m
wing area	9,15 m2
aspect ratio	13,22
wing airfoil	FX 66-S196
empty wt.	95 kg
max payload	90 kg
MTOW	185 kg
stall speed	52 km/hr
maneuvering Speed	110 km/h
VNE	150 km/h
max glide	22
min sink	1 m/s
Performance based on preliminary calculations

As you can observe in picture above, the Hornet is made similar to wooden RC model sailplane. The fuselage structure is made by plywood bulkheads from 6 to 12 mm thick. Over those bulkheads runs 4 structural longerons This skeleton is covered by glueing 1 to 1,5 mm thick birch plywood over it. Inside surfaces are protected from humidity by epoxy and outside is painted with polyurethane based paint or similar.

The main wing ribs are made from 6 mm plywood, but between them you can find also ribs from 20 mm thick blue foam that support the skin and preventing the skin buckling. The root assembly does not represent complete design, but only want to show how it will looks...someday...

The wooden sailplane can take more atractive paintwork compared with composite sailplanes (always white) because wood is litle more resistant to sun heat.

The wingspar is made from graphilite (carbon) rods, plywood webs and styrofoam core between both shear webs. The ribs are cut from plywood. In the nose section you can find styrofoam aditional ribs, that prevent buckling of the torsion nose plywood skin.

The airfoil FX 66-S196 is choosen because of relative thick shape and because it is apropriate for slow flying light sailplanes, with no ambitions for high interthermal speeds.

Fuselage has enough room for power unit, that can be retracted as is visible on drawing above.

There could be possible to deatach outer tapered part of wings (left an right of course) and install so called Winggrid. Winggrid increase wing efficiency, so even with such shortened wings the Hornet should fly equally or even better than with tapered outboard part of wing. This is not yet investigated on Hornet, but soon I will made calculations to check... The winggrid produce high lift, so it is stressed a lot and also the outboard of wing. It is question here if this instalation is worth to think about?? And also on bird looks better than on aeroplane... a? There is also a Catch here! The winggrid is patented!!