1. Aerial inventions in motorless flight
Kevin Kochersberger, Ph.D.
Virginia Tech,
Mechanical Engineering
Blacksburg, VA

2. The first significant scientific research into
manned flight started with Sir George Cayley
Sir George Cayley (1773 - 1857)
Successful engineer
Designed several airplanes, flew
a successful glider model,
measured lift using a whirling arm
device
Had limited success with full
scale aircraft
1804
1852

3. Cayley’s coachman became the first aircraft
passenger in 1853
Derek Piggott flying the Governable Parachute in 1973

4. Jean-Marie LeBris was inspired by
observations of the Albatross
Jean-Marie LeBris (1817 – 1872)
Built a 50’ span glider, the Albatross, and (maybe) managed a
short gliding hop in 1856 – some flight reports were greatly
exaggerated which puts into question his credibility
Improved on the design in 1868 (below), but only flight may
have been unmanned and out of control

5. Francis Wenham built the first wind tunnel in
1871
Francis Wenham (1824 - 1908)
His wind tunnel verified the advantages of long, slender
wings (observed in soaring birds)
Wenham was the first to suggest superposing planes to
increase lift and structural efficiency – published paper
“On Aerial Locomotion…” (1866)
Wenham’s superposed wing concept

6. Insightful observations and a machine
Louis Mouillard (1834 – 1897)
Published “The Empire of the Air” in
1881on the observations of bird flight,
which Chanute took interest in
Proposed fixed wing gliders
Designed and built a simple winged
apparatus and achieved a 138 ft glide
Mouillard’s work inspired Chanute to
fund him to build a two-axis control
machine, but no success came from this

7. The experiments of Prof. John Montgomery
John Montgomery (1858 – 1911)
Montgomery was the first person in
the U.S. to successfully fly a glider
Although the documentation is
sketchy, he is likely to have flown a
glider with pitch control in 1883 in
Otay Mesa, CA
This flight was short – 100 feet despite
reports of longer flights
Later, David Maloney flew a
successful tandem wing glider for
exhibition (1905) from balloon launch
Clip from Gallant Journey 1946, starring Glenn Ford
as John Montgomery, directed by William Wellman

8. Horatio Phillip’s wind tunnel used steam
injection to develop a clean airflow
Horatio Phillips (1845 – 1912)
Tested cambered airfoil shapes
He was the first to recognize
that low pressure created on
the upper surface of the wing
contributed to lift
Designed a steam powered,
venetian-blind type test vehicle
to evaluate lift of superposed
wings

9. Percy Pilcher conducted towed glider flights
in the hopes of building a powered machine
Percy Pilcher (1866 – 1899)
Pilcher was focused on flight at
a young age, and experimented
in aeronautics at the University
of Glasgow
The most 1892 – 1893, built the Bat and
famous yaw flew 30 – 40 ft from a shallow
string! hill
He designed the Hawk and flew
many towed flights 1897 – 1899
Pilcher was fatally injured in
the Hawk on Sep 30, 1899

10. Lilienthal was both a credible scientist and
aerial experimentalist
Otto Lilienthal (1848 – 1896)
Measured lift and drag on
cambered airfoils with a
whirling arm device and a
balance in natural wind
Men do laundry!
Noted the effect of camber lift
on clothes in the wind

11. Lilienthal produced (for the first time)
accurate lift and drag polars
The Wright brothers would refer to these published tables and
graphs for their wing designs
Parabolic shape, 1/12 camber ratio
From “Birdflight As The
Basis Of Aviation”

12. Lilienthal’s 1st successful glider design –
Flown near Derwitz/Krielow in Brandenburg
Note flying apparel
1891 – 80 foot flight achieved

13. Lilienthal’s glider designs
They showed a classic hang glider configuration
Effective control was proven for thousands of glides and five hours
of flight time, 800 ft glide achieved in 1893
1893 1895
1894 – the “Normal glider” 1896 – crashed normal glider

14. Octave Chanute – Railroad engineer turned
aerial experimentalist
Octave Chanute (1832 – 1910)
Chanute left the Erie Railroad as a
successful railroad bridge designer
and executive in 1883, but continued
to work in a variety of engineering
interests
In 1886, Chanute chaired the AAAS
Mechanical Science Section meeting in
Buffalo, NY where he introduced flight
as a topic
In 1894, published Progress in Flying
Machines

15. Chanute flew multi-wing glider designs with
the help of Augustus Herring
Looking for collaboration, Chanute
found Augustus Herring, a builder of
some moderately successful gliders
in 1894
In 1896, several experiments were
conducted on the south shore of Lake
Michigan with the Katydid

16. The Katydid flights were short but safe
“My assistants made some 150 –
300 jumps during the two weeks
we were at camp, say from 30 to
100 feet in length and not the
slightest accident occurred.”
The Katydid patent
incorporated automatic
stabilization by hinging the rear
portion of the wings, or a tail
surface

17. Returning the Chicago, another glider was
quickly designed and built
The 1896 Chanute-Herring triplane/biplane glider was
designed and flown later in the summer
Utilizing the Pratt truss design, this glider resembled a
railroad bridge from the front view
1896

18. And then, the Wright brothers...
Wilbur (1867 - 1912) Orville (1871 - 1948)

19. Early Experiments
Flight experiments begun in 1899
with a 5’ wingspan kite
Proved the wing warping concept
The Wrights realized that control
was still an unsolved problem
(unlike the majority of aerial
experimentalists)
Weight shift and flexible surfaces
were commonly used

20. The 1900 glider – first to fly at Kitty Hawk
“For some years, I have been afflicted with the
belief that flight is possible to man…”
Wilbur Wright to Octave Chanute, May 13, 1900
1900
The 1900 glider was sized around
Lilienthal’s calculations
The front “rudder” position was settled
on after trying a rear mounted
configuration
It was believed that the center of
pressure was kept more constant with
angle of attack and prevented a nose
dive attitude
1900 Glider Specifications
Wingspan: 17.5’ (2’ less than planned due to wood availability)
Chord: 5’
Wing area: 165 ft 2

21. The 1900 glider flight test results
Kiting the glider served to
measure lift and drift (drag)
2001 Because of the smaller-than-
planned size and low aspect ratio,
angles of attack were large,
resulting in more drag
“…hours of practice we had
hoped to obtain finally
dwindled down to about two
minutes…”
Distances of 300’ – 400’ achieved
with a 6:1 glide angle descending
down hill

22. The 1901 glider was designed to correct the
deficiencies of the 1900 glider
1901
More kiting experiments proved the
lifting capacity was still less than
predicted
Without pilot, the glider lifted 98 lbs.
with 15 lbs. of drag.
Effective L/D = 6
But lifting capacity 1/3 of predicted for
given wind speed and AOA
Lilienthal’s lift coefficients were correct,
but:
The Smeaton coefficient was incorrect
The AR was low
1901 Glider Specifications There was a huge gap in the lower wing
Wingspan: 22’
Chord: 7’
Wing area: 290 ft 2

23. Some success, but not enough...
Pitch instability corrected by
“trussing down” the wings
Longest flight: 389 ft.
Actual lift was much less than
predicted
And a turn to the right...
View looking
Forward
...Became a turn to the left!
???

24. Engineering a solution
The Wrights’ kiting experiments
confirmed lift theory was incorrect
They needed to quantify airfoils, so a
wind tunnel was built to determine
accurate lift and drag for over 200
tested shapes
Effects of camber, thickness and
aspect ratio were documented as a
function of angle of attack

25. 1902 Glider

26. 1902 glider: A modern airplane
A high aspect ratio wing
Anhedral added
Improved camber (curvature)
L/D increased from 5 to 7
Three axis control: with the
addition of a moving tail, turns
were now predictable
250 flights made in a 5-day
period in October
Longest flight: 622 ft.
Time aloft: 26 seconds

27. Adverse Yaw Corrected
0.008
1901 Glider
0.006
1902 Glider
0.004
Cn
0.002
0
0 5 10 15 20
-0.002
-0.004
Angle of attack, degrees

28. And more warp power
0.03
0.025 1901 Roll Control Power
1902 Roll Control Power
Roll Coeff, Cl
0.02
0.015
0.01
0.005
0
0 5 10 15 20
Angle, degrees

29. But still have a variable stability aircraft
0.07 Unstable!
0.05 1901 Glider
1902 Glider
0.03
Cm
0.01
-5 -0.01 0 5 10 15 20 25
-0.03
-0.05
Angle of Attack, degrees

30. Flight testing of the 1902 glider

31. The 1902 glider was used in 1903 for
recurrent training prior to the powered flights
On October 21, 1903, Orville and
Wilbur made several glides in the
1902 glider, setting new endurance “The early part of the glides
records. was practically soaring, our
speed over ground being
Greatest endurance: 1 minute, ½ sec from one to two feet per
second, often for distances
of 25 to 75 feet…Many of
these flights were at
heights from 40 to 60 feet,
by far the highest gliding
we have ever done.”
Orville Wright

32. What is it like to fly the Flyer?
Non-ergonomic design
Canard lever and hip cradle
controls awkward
Back must be arched for forward
visibility
No throttle, fuel cut-off operated
by right hand shuts down engine
On rail, the pilot concentrates on
keeping wings level to avoid
wingtip strike
No instrumentation!

33. What is it like to fly the Flyer?
Laterally, the aircraft
responds well to warp
input
Crosswind conditions
should be ignored…keep
wings level!
The airplane does fine
in a sideslip

34. The 1903 Flyer was successful because of
the Wrights’ extensive experience in gliders

35. The Wright 1909 Glider
Responding to European
demand for aircraft, the
Wrights suggested that pilot
training begin in a glider
Messrs. T. W. K. Clarke and
Co. constructed a glider for
Alec Ogilvie and Ted
Searight, who had ordered a
1909 Wright Model A
The glider looked very much like the
1908 machine flown in Europe by
Wilbur, with a 32.5’ wingspan

36. The Wright 1909 Glider
Several successful flights of the
1909 glider were documented, with
Orville recording a 250 yd flight
The controls were awkward – the
standard for Wright aircraft!

37. The Wright 1911 Glider (Glider #5)
October 7, 1911: Orville, Lorin and
Alec Ogilvie leave Dayton for Kitty
Hawk with Glider #5
A design based on the Wright EX
Note Wright Flyer – A.K.A. the Vin Fiz
controls
The trip’s reported purpose
was to test an automatic
stabilization system,
however only manually
controlled flights were made
1911 Glider #5 Specifications
Wingspan: 32’
Chord: 5’
Gap: 3’ 9”
Wing area 300 ft 2
Weight 170 lbs

38. The Wright 1911 Glider controls
The same awkward control we see
on the 1908 – 1911 powered
machines
Rudder is interconnected to the
wing warp control, biased with
wrist motion
Wright Model B controls in Grover
Berghdoll’s Machine at the Franklin
Institute, Philadelphia, PA

39. The Wright 1911 Glider (Glider #5)
October 16 – Orville notes
shortcomings of the design:
“Shot up at landing and dropped
about 6’…Horizontal rudder too
small…Vertical rudder too small”
- Tail surfaces are enlarged
and a front vane added from
1905 rudder
“After one glide in which I
pitched out of machine, put in
larger rudder using center of
1905 rudder”
O. Wright

40. The Wright 1911 Glider (Glider #5)
October 18: Wind and rain
“Made several glides. In last one
machine turned around in spite of
all I could do and run into hill
turning over. Broke both left wings
and rear horizontal surface.”
O. Wright
“…Wright climbed to an upright
position of safety…This
experience suggests that it is a
mistake to strap the aviator to
his seat as is done in many of
the monoplanes, and that
frequent accidental injury might
be avoided by a good use of
similar cool-headedness in time
of danger”
Hayward, Practical Aeronautics, 1912

41. A soaring endurance record is set
October 19, 20: Repairs
made and tail extended 4.5’
October 24: “Wind 20 –
25 on ground. Wind at
KD Hill 40 miles at 6 ft, as
high as 50 miles 12 ft.”
O. Wright
20 flights made, three
longest were:
9 min, 45 sec
7 min, 15 sec
5 min, 29 sec

42. Epilogue
Orville stated in a 1919 letter to
Lawrence Driggs that “Our
early experiments at Kitty
Hawk were conducted…to
learn something about soaring
flight.”
Paul Schweizer concluded that
Orville’s flights were mainly “for
fun.” They were the first
recreational soaring flights.

43. The 9 min, 45 sec soaring endurance record
stood for 10 years, until Aug 20, 1921
Wolfgang Klemperer and fellow students from Aachen University designed
and built the Schwarze Teufel in 1920. Improvements to the design in 1921
resulted in the Blaue Maus, and a 13 minute flight that took the endurance
record from Orville

44. Conclusions
Many aerial experimentalists contributed to the science of
aviation, but no one was “putting it all together”
Control was the Wrights’ big contribution to aviation
Flight research prior to their work was focused on lifting surfaces,
which limited the functionality of aircraft
The 1911 Flights were undoubtedly the most whimsical of
any that were conducted by the Wrights, and for this reason,
the sport of recreational soaring was born

45. Acknowledgements
Simine and Jim Short
Neal Pfeiffer
Ken Hyde and the Wright Experience team
Rick Young

46. Gliding History Symposium
Symposium Coordinator: Dr. Tom Crouch, Senior Curator
Smithsonian National Air & Space Museum
SOARING VISIONARIES
Jockey’s Ridge State Park Auditorium
Tom Crouch: Birth of Gliding, Cayley to Lilienthal
Peter Jakab: Wright Gliders 1900-1902
John Anderson: The Wright Brothers as Engineers
Russell Lee: The Impact of Soaring on Aviation
Bernd Lukasch: Otto Lilienthal and Sailing Flight
Simine Short: Octave Chanute and Company
Rick Young: Orville Wright and the 1911 Glider Trials
Paul Dees: Engineering Wright Gliders

47. Hang Gliding Legends
A once in a lifetime panel on the development of hang gliding and the visionary contributions of
Francis Rogallo

48. Acknowledgements
Neal Pfeiffer
Simine Short
Jim Short
Paul Dees
Rick Young
Ken Hyde
The Wright Experience
Discovery of Flight Foundation
Rochester Institute of Technology