A wing is described for aircraft of cropped, arrow-type planform with thin leading and side edges. The wing has a pivotable tip to alter the crop angle of the wing during flight. Increasing the crop angle causes the wing side edge to become a trailing edge which reduces the strength of the side edge vortex flow. Decreasing the crop angle causes opposite results, in particular the side edge is now a leading edge and can generate a leading edge vortex flow. The wing constitutes a roll control device for aircraft of the stated design particularly effective at higher angles of attack

Lamar, J. E.

English

NASA Technical Reports Server

United States Patent 1191 
Lamar 
[54] VORTEX-= ROLL-CONTROL DEVICE 
[75] Inventor: John E. Lpmpr, Newport News, Va. 
[73] Assignee: The United States of America as 
represented by the Administn tor of 
the National Aeronautics aud Space 
Administrrr tion, Washington, D.C. 
[21] Appl. NO.: 779,42!3 
[22] Filed: Mar.21,1977 
Related US. Appliation Data 
[63] Continuation of Ser. No. 651,002, Jan. 21, 1976, 
abandoned. 
[51] Int. (3.2 ........................... B64C 3/W, B64C 5/08 
[52] US. c1. .................................. 244/90 R; 244/218; 
24/46 
[SS] Field of Search ................... 244/218, 46, 49, 199, 
24/90 R 
r56I Relereneee Cited 
U.S. PATENT DOCUMENTS 
1,982,242 11/1934 Bellanca ............................... 244/218 
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[I11 4,132,375 
[451 Jan. 2,1979 
2,222,997 11/1940 Ballanca et al. ..................... 24/218 
3,273,828 9/1966 James ................................... 24/218 
3,493,197 2/1970 Spearman ............................. 244/218 
3,497,163 2/1970 Wakefield ............................ 244/218 
3,599,904 8/1971 Condit .................................... 24/49 
Primary Examiner-Galen L. Barefoot 
Attorney, Agent, or Firm-Howard J. Osborn; John R. 
Manning; Wallace J. Nelson 
[57l ABSTRACT 
A wing, for aircraft of cropped, arrow-type planform 
with thin leading and side edges, having a pivotable tip 
to alter the crop angle of the wing during flight. In- 
creasing the crop angle causes the wing side edge to 
become a trailing edge which reduces the strength of 
the side edge vortex flow. Decreasing the crop angle 
causes opposite results, in particular the side edge is 
now a leading edge and can generate a leading edge 
vortex flow. The wing constitutes a roll control device 
for aircraft of the stated design particularly effective at 
higher angles of attack. 
6 cllms, 2 Drawing Eysares 
https://ntrs.nasa.gov/search.jsp?R=19790005937 2020-03-20T17:54:56+00:00Z
U.S. Patent ~ m .  2,1979 Sheet 1 of 2 4,132,375 
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FIG. 1 
U.S. Patent ~ m .  2,1979 
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4,132,375 
VORTEX-LIFT ROLCCONTROL DEVICE 
ORIGIN OF THE INVENTION 
The invention described herein was made by an em- 5 
ployee of the United States Government and may be 
manufactured and used by or for the Government for 
governmental purposes without the payment of any 
royalties thereon or therefor. 
filed Jan. 21, 1976, now abandoned. 
This is a continuation, of application Ser. No. 651,002 10 
BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a roll control device having 15 
particular application to aircraft possessing a cropped, 
arrow-type planform with thin leading and side edges, 
control being achieved by altering the wing surface area 
which a shed vortex system provides lift against. 
craft, with solutions being varied and numerous. Gener- 
ally, tip- and trailing- edge ailerons, partial span flaps, 
horizontal tails or spoilers are used to provide rolling 
moments for maneuverability and control in aircraft 
having transonic and suupersonic capability. There are, 25 
however, disadvantages to these solutions. Specfically 
rolling moment effectiveness falls off as the angle of 
attack is increased. The devices are also susceptible to 
reversal where deflection of the control surface induces 
elastic distortions so as to create an aerodynamic mo- 30 
ment of the opposite sense to the control surface deflec- 
tion and of such magnitude that no resultant control 
moment is produced. Furthermore, the devices produce 
an unfavorable yawing moment when deployed. The tip 
aileron poses a separate problem since it is an added-on 35 
aerodynamic surface which, under the expected local 
flow conditions, would produce increases in the local 
loadings. Hence, a structural problem could result. 
It is therefore an object of the present invention to 
disclose a roll control device having increased rolling- 40 
moment effectiveness at the higher angles of attack. 
A further object of the invention is to provide a de- 
vice producing increased roll-rates over a wide angle of 
attack range. 
The problem of roll control is evident with all air- 20 
An additional obiect of the invention is to Drovide a 45 
roll control device iot  as susceptible to revers& as prior 
devices. 
Another object of the invention is to provide a roll 
control device which produces no or favorable yawing 
moments in flight. 
A further additional object of the invention is to 
provide a device which utilizes leading- and side-edge 
shed vortex systems to impart rolling moments to an 
aircraft for maneuverability and control. 
2. SUMMARY OF THE INVENTION 
Vortex flows, such as those associated with edge 
separation, and their accompanying flow re-attachment, 
are encountered at many points within the flight and 
maneuver envelopes of high-speed aircraft. While per- 
forming wind tunnel tests to determine if a mathemati- 
cal aualogy correlated with empirical data, it was dis- 
covered that vortex flow around the side edges of an 
aircraft having a cropped arrow planform produced lift. 
Hence, it was hypothesized that if there was a method 
of weakening the vortex flow on one wing panel, a 
significant amount of r o h g  moment could be pro- 
duced, especially at the higher angles of attack where 
ailerons are generally ineffective. It was discovered that 
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alteration of the crop angle, that is, a change in position 
of the wing tip side edge from parallel with the longitu- 
dinal plane of symmetry of the aircraft to another posi- 
tion, of one or both wing panels to create an asymmetri- 
cal aircraft planform produced such a rolling moment. 
In the present invention a powered aircraft having a 
conventional fuselage, is provided with a segmented 
wing projecting from each side of the fuselage. Each 
wing includes a main wing panel having a swept leading 
edge and an outboard tip control panel pivotally con- 
nected to the main wing panel near the outboard edge 
thereof for rotation in the wing areal plane. The tip 
control panel possesses a substantially straight tip edge 
which, when positioned parallel with the longitudinal 
plane of symmetry of the aircraft, is subject to the vor- 
tex flow present there and hence contributes to wing 
lift. 
By varying the position of a tip edge so that it no 
longer parallels the longitudinal plane of symmetry but 
rather extends rearwardly and inwardly, the wing sur- 
face area behind the leading edge tip subject to vortex 
flow is reduced resulting in a similar reduction in wing 
lift. By positioning the other tip control panel in asym- 
metrical relation to the first, a rolling moment will be 
imparted to the aircraft in the direction of the wing 
possessing the smaller lift component. 
Since vortex lift increases with angle of attack, roll- 
ing moment effectiveness does not fall off as the angle of 
attack is increased. Furthermore, yawing moment is 
absent or favorable. Additionally, the devise is not as 
susceptible to reversal since roll control is accomplished 
without deflection of a surface into the air stream. 
A more complete appreciation of the invention and 
many of the attendant advantages thereof will be 
readily apparent as the same becomes better understood 
by reference to the following detailed description when 
considered in connection with the accompanying draw- 
ings wherein: 
FIG. 1 is a plan view of the segmented wing aircraft 
of the present invention with the wings thereof disposed 
such that tip vortex lift is a component of total wing lift 
on both wings; and 
FIG. 2 is a plan view of the segmented wing aircraft 
of the present invention with the right wing thereof 
disposed such that tip vortex lift on the left panel is 
effectively removed while on the right panel additional 
vortex lift in the tip control area is generated thus im- 
parting a rolling moment to the aircraft. 
DETAILED DESCRIPTION 
Referring now the drawings wherein like reference 
numerals designate identical parts throughout the sev- 
eral views, and more particularly to FIG. 1, there is 
shown an aircraft of variable crop angle generally des- 
ignated by the reference numeral 11. Aircraft 11 is pro- 
vided with a conventional fuselage 12 having a length 
to equivalent diameter or fmeness ratio, suitable for 
transonic and/or supersonic fight. A suitable control 
compartment or pilots cabin, is also included in fuselage 
12 adjacent the forward end thereof, in a conventional 
manner. A conventional empennage assembly including 
a vertical stabilizer member 14 projecting upwardly 
from the upper surface of fuselage 12 and swept hori- 
zontal stabilizer members 15 projecting outwardly from 
the aft end of fuselage 12 are also provided. The airfoil 
sections of these stabilizer members 14 and 15 are pref- 
erably taken from the supersonic family of symmetrical 
thin airfoils. 
4,132.375 
Aircraft 11 is provided with a wing projecting out- 
wardly from each side of fuselage 12 and generally 
designated by the reference numeral 17. Each wing 17 
includes a main wing panel 18 having a then straight 
leading edge 19 and a straight trailing edge 21 which 
converge outwardly toward a tip section 22, angles 
inwardly. Each wing 17 also includes an outboard tip 
control panel 31. Each tip control panel includes a sub- 
stantially straight thin side edge 32 and a root section 
having an arcuate forward portion 33 which flares into 
a substantially straight after portion leading to an angu- 
lar intersection with the curved trailing edge 34. 
The root of tip control panel 31 extends into main 
wing panel 18 through a suitable slot formed in the tip 
section 22 thereof, not illustrated, and occupies a suit- 
able recess within the main wing panel 18. Tip control 
panel 31 is suitably connected to main wing panel 18 for 
rotation in the wing areal, or planform, plane about a 
pivot point 23 located within main wing panel 18 near 
the forward portion of tip section 22 thereof and which 
is located in the forward portion of tip control panel 31. 
Pivot panel, or connection 23, for tip control panel 31 
may be suitable steel pin and bearing arrangement or the 
like and extends perpendicular to the plane of main 
wing panel 18 for rigid connection with tip control 
panel 31. Conventional actuators 40 and linkage 41 are 
provided to afford selective relative pivotal movement 
of the outboard tip control panels 31 and would be 
controlled by the pilot of the aircraft as conventionally 
with the other controls. The linkages 41 are fixed to the 
aft end of the root sections 35 of tip control panels 31. 
The linkages are also connected to actuators 40 occupy- 
ing a suitable recess within the main wing panel 18. The 
actuators 40 may be pneumatic, hydraulic or some other 
mechanism capable of imparting a translational move- 
ment to the linkages 41. 
OPERATION 
Thus, during takeoff, climb and cruise, a swept 
4 
Should a larger rolling moment be desired, tip control 
panel 31" may be swept out into the position shown in 
FIG. 2, to provide a slight increase in wing surface area 
exposed to the vortex flow 50 present in that region. 
5 Such asymmetrical tip position would further unbal- 
ance the lift components between the wings thereby 
increasing the aircraft roll rate. 
It is to be understood that aircraft 11 may be provided 
with any conventional propulsion engines, pitch and 
10 yaw control surfaces landing gear and the like equip- 
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cropped planf0;rm such as shown in FIG. 1 is desirabie, 40 
as discussed hereinbefore. By positioning tip control 
panels 31 with side edges 32 parallel with the longitudi- 
nal plane of symmetry of the aircraft vortex flows 50 
acting along the wing side edges 32 produce a compo- 
nent of wing lift. However, during certain aircraft ma- 45 
neuvers such as a bank or roll, it is necessary to unbal- 
ance the lift components on the wings to impart a roll- 
ing moment to the aircraft. Turning now to FIG. 2, it 
may be seen that the present invention provides a vari- 
able crop angle aircraft which possesses such capabili- 50 
ties. During the maneuvers hereinbefore referred to, 
outboard tip control panels 31 may be pivoted through 
the instrumentality of the means aforementioned to the 
positions shown in FIG. 2, wherein left tip control panel 
31' is pivoted into main wing section 18' while right tip 55 
control panel 31" is pivoted out from main wing section 
18. 
In sweeping left control panel 31' into the main wing 
section 18, side edge 32' is removed from the vortex 
flow which thereby reduces the lift on the left wing 17' 60 
by an amount approaching 31' vortex lift component. If 
right wing 17" and its tip control panel 31" remained in 
the position shown in FIG. 1, a rolling moment would 
be imparted to aircraft 11 since lift attributable to the 
vortex 50, present along the tips, would remain a com- 65 
ponent of total wing lift on right wing 17" while the lift 
on left wing 17' would be diminished by the amount 
previously attributable from vortex 50. 
ment normally found in such-&craft without depa&g 
from the scope of this invention. Such equipment is not 
shown, since it forms no part of the present invention. 
Obviously, many modifications and variations of the 
present invention are possible in the light of the above 
teachings. It is therefore understood that within the 
scope of the appended claims the invention may be 
practiced otherwise than as specifically described. 
What is claimed as new and desired to be secured by 
Letters Patent of the United States is: 
1. A roll control for an aircraft having a swept 
cropped planform capable of subsonic, transonic and 
supersonic flight comprising: 
a fuselage; 
a wing having a highly swept cropped planform con- 
nected to each side of said fuselage; 
each said wing including a main wing panel having a 
leading edge, a trailing edge and a tip section ex- 
tending from the tip of the leading edge inwardly 
and rearwardly with respect to the longitudinal 
plane of symmetry of said aircraft; 
each said wing further including a tip control panel 
pivotably connected to said tip section and having 
a tip edge which defines the outboard edge of said 
means for independently moving each said tip control 
panel from a first position where said tip edge is 
substantially parallel to said longitudinal plane of 
symmetry to a retracted ,position extending in- 
wardly and rearwardly toward said plane whereby 
said tip edge thereof contiols the intensity of the 
leading edge and side edge vortex lift generated by 
the shed vortex system resulting from separated 
flow and subsequent flow reattachment in the re- 
gion of said tip edge. 
2. The roll control of claim 1 wherein each said tip 
control panel is pivotable in a substantially horizontal 
plane. 
3. The roll control of claim 2 wherein each said tip 
edge is substantially straight and is subject along its 
entire length to said edge vortex lift when positioned 
parallel to the longitudinal plane of symmetry of said 
aircraft. 
4. In the roll control of claim 1, wherein each said tip 
control panel is moveable such that said tip edge ex- 
tends rearwardly and outwardly with respect to the 
longitudinal plane of symmetry of said aircraft thus 
increasing the intensity of side edge vortex lift acting 
along said leading edge and tip edge and the area of said 
wing thereby increasing lift on said wing. 
5. The roll control of claim 4 wherein said indepen- 
dent means can move said tip edges such that one said 
tip edge extends rearwardly and outwardly. 
6. A roll control as in claim 1 wherein: 
each of said main wing panel is fixed to said fuselage; 
each of said pivotable outboard tip control panels 
including a leading edge, and a trailing edge and is 
connected to each of said inboard wing panels in 
wing; 
4,132,375 
5 6 
substantially coplanar relation therewith for rota- 
tion within predetermined l i t s  in a substantially 
horizontal plane about a pivot point; 
each of said pivot points being located on a chord line 
of an outboard tip control panel near the leading 5 
edge thereofi 
proximate the tip section of said inboard wing 
panel whereby said tip control panels are indepen- 
dently movable such that said tip edges thereof 
control the intensity of side vortex lift generated by 
the shed vortex system resulting from separated 
flow and subsequent flow reattachment in the re- 
gion of said tip edge. each of said pivot points further being located with 
respect to the inboard main wing panel closely * * * * +  
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Vortex-lift roll-control device

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