Thursday, September 17, 2009

Basic properties of the flapping wing and features of the flapping flight

The principles of the flapping flight of all flying creatures realized either by birds or by insects are just the same. THE FLAPPING WING HAS AN ELASTICITY BOTH ALONG THE SPAN AND THE CHORD. The elasticity along the span conduces to the smoothness and high effectiveness of the flapping flight. The adaptive elasticity of the wing along the chord make it possible to achieve a maximum traction in a wide range of frequencies and amplitudes of the flaps. THE TRACTION IS CREATED BY THE OUTER PART OF THE WING WHILE THE INNER ONE GENERATES THE MAIN PART OF THE LIFT. When the inner part of the wing is moving upward the outer part lags and bends downward in relation to the inner part because of the air drag and inertial forces. In this way the drag of the wing as a whole diminishes. When the inner part is nearing the up position the elastic forces raising the outer part upward and latter continues to create traction while the reaction aids the inner part and the wing as a whole to pass across the up position and to begin moving downward.THE WING ELASTICITY ALONG THE CHORD IS SUCH THAT THE WING PRACTICALY DO NOT BEND IN GLIDING-EQUILIBRIUM POSITION.
The direction of the wing flapping motions is not perpendicular to the flight direction but with declination backwards which decrease by increasing of the flight velocity. The wing behavior and the aerodynamic forces action during a flapping motion are shown on fig.1.(The lines of the paths at the scheme are projections of the solid lines.)


FLAPPING WING AERODYNAMIC FORCES
V - flight velocity
U - flapping motion velocity
W - total wing velocity
X - drag
P - TRACTION ( U > V ), LIFT ( U < V )
R - total aerodynamic force

It is evident from fig.1 that during both the downward and upward motion the outer part of the wing is creating the traction, while the inner part does the lift.In the course of the flapping motions the wing behavior automatically results from the inherent elasticity of the wing.The inner part of the wing produce lift during the upstroke too, because the flapping motion velocity U is little in comparison with the flight velocity V and the inner part is twisted downwards in equilibrum position.
THE FORCES ARE DIFFERENT(SIZE AND DIRECTION)IN EACH SECTION OF WING AND IN EVRY MOMENT OF CYCLE OF THE FLAPPING FLIGHT.

THE AIR STREAM OF THE FLAPPING WING IS FAN-SHAPED AND IS IN DEPENDANCE FROM CORRELATION FLIGHT VELOCITY/FLAPPING MOTION VELOCITY FOR THE DIFFERENT SECTIONS.
The above statement clarifies the flapping flight mechanism. It is important to point out that the mass distribution and the mass/elasticity ratio are of great significance for a maximum flapping wing efficiency. THE MASS / ELASTICITY RATIO IS DISTRIBUTED OVER THE WING IN A WAY ALLOWING THE WING - WHEN BENDED AND THAN RELEASET - TO COME BACK TO THE EQILIBRIUM POSITION WITHOUT VIBRATION
As result the wing bend along the chord only under air resistance but not under inertial forces. This property determinate the way of bending of the wing at the flapping movements, that decide the problems of the mechanics and aerodynamics of the flapping flight, pitching and hering.
These conclusions illustrated by the wing behavior at level flight but the described properties and relationships give the opportunity to explain the other types of modes of the flapping flight. 

                                                              May 1994


                           






































September 2011


Wednesday, September 16, 2009

ORNITHOPTER



















Manned ornithopter with 8m. span




















RC model of ornithopter with 2m. span













                             ORNITHOPTER - 1978

















Variant of invention "Wing of ornithopter", realized by RC model




 








Variant of invention "Wing of ornithopter"




                                Ornithopter with passive articulated adaptive wing



                                                                   The future...






MANNED ENGINE-POWERED ORNITHOPTER.
span - 10 m
chord - 1.5 m
weight - 85 kg
(At the images it is withowt elastic rips and fabric of the wings.)
The ORNITHOPTER have articulated wings and control of the elasticity of the wings.
The up-down control is through change of the angle of incidence of the wings. The left-right control is through rear-lower ruder, connected with the control of the fore-wheel. The tail is fixed.
At take-off the pilot move the control levers forward. The angle of incidence increase, the flapping frequence (gas) and initial tension of the springs (behind the roller on the control lever) connected with outer parts of the wings increase too.
At the left control lever is the handle of the clutch, at the right control lever is the handle of the stopper of the control levers.



































                                                                                                                                                           HUMAN POWERED ORNITHOPTER

Tuesday, September 15, 2009

Monday, September 14, 2009

ORNITHOID
















The ORNITHOID is combination of my project of ornithopter and 
the project of ornithopter (ornithoid) of The University Of Toronto.












Rubberpowered model of ORNITHOID

span - 85cm
weight - 120g
chord - 12cm
amplitude - 10cm
The wing have upper feathers - its form and size determine the elasticity of the wing along the chord. The resistance of the wing upwards is less than downwards.
















Variant of mechanics of rubberpowered model of ORNITHOID.




Electric - powered model of ORNITHOID.
Span - 2m.
Weight - 1,5kg. 



HUMAN POWERED ORNITHOID



























Span - 9 m
Weight - 22 kg
Chord - 1.6 m
The wing is at midle position. It have two additional supports at rest.

















ADAPTIVE ORNITHOID WING



















ADAPTIVE ORNITHOID WING. THE X - DETAIL SUPPORT THE WING AT REST







































HP ORNITHOID WITH ASSISTANT SPRING









Sunday, September 13, 2009

ENTOID























The wings flapp (rotate) 360 degrees in vertical and in horizontal mode.
In horizontal mode the flapping (rotating) wings create trust and lift.



















Rubber powered model of ENTOID

 

Electric - powered model of ENTOID

 

The wing consist of flexible lamelles and elastic bands.
This wing is adaptive and suitable for horizontal mode of flight of ENTOID. 



ADAPTIVE ENTOID WING





















  
 ROTATING ELASTIC WING













V - flight velocity
U - rotating motion velocity
W - total wing velocity
X - drag
P - traction (U>V), lift (U<V)
R - total aerodynamic force

Saturday, September 12, 2009

Links

The ornithopter zone - http://www.ornithopter.org/
Univrsity of Toronto - Manned ornithopter - www.ornithopter.net
The site of Horst Räbiger - http://www.ornithopter.de/english/index_en.htm
Website of Patricia Jones-Bowman www.ornithopter-pilot.com
Dr R.Korobelnic's Flapping flight Site - http://ovirc.free.fr

The old site of Velko Velkov- http://reocities.com/Eureka/boardroom/9483/velko.htm