AVIATION'S NEW ERA
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Chapter 5. Improving the Flat Plate Airfoil
Overcoming Pitch Instability – A widely-applicable application of a flat plate airfoil is to convert the upper surface of an aircraft to a lift generating surfaces, such as illustrated by Figure 5. Doing this on upper and lower surfaces may potentially double the lift on an aircraft with minimal increase in drag. While this may create new challenges for maintaining cabin pressure at high altitudes, there are many applications for drone aircraft and air taxis where pressure is not a factor.
An issue presented by the Figure 5 design configuration is the sudden change of lift from positive to negative as air’s angle of attack goes from 1° to -1°. At -1°, the negative lift and weight combine to cause a rapid nosedive, creating high instability to steady flight. The flat top of the aircraft is the cause of the instability, and essentially any traditional control surface would be too small to maintain stability.
A series of patents by G. Suppes provide solutions to this instability. The “Towed Platform” configuration is a lead delta wing aircraft pulling a platform, a hinge joint provides stability through adding flexibility to the design. Figure 6 illustrates such an aircraft. For the towed platform, a negative lift from a dip in the delta wing front results in a pivot action about the hinge joint and a return to positive air angles of attack; it is inherently stable, unlike the rigid structure. Figure 7 illustrates how lift torque and load torque passively actuate to equal and opposite values for passive stability.
Also, a contiguous and streamlined connection of a Towed Platform to a lead aircraft does not introduce form drag from a new front edge. This allows for incremental expansion of the capabilities of the lead aircraft, one of which is the addition of a large surface area for solar energy collection where the Towed Platform provides considerably more power than is needed to tow the platform.
Ultra-Light Weight Configurations – As a flat plate airfoil, the structure of the airfoil may be a single-layer thin canvas or board between support structures. This approach allows for ultra-light weight construction; construction that has less weight per area than can be achieved with a traditional airfoil.
When upper and lower surfaces of a fuselage may be configured to operate as flat plate surfaces, lateral extensions from the fuselage sides can be made with minimal weight penalty.
Overcoming Low Structural Strength – To overcome structural requirements of wings, the flat plate airfoil of Figure 5 has a very low aspect ratio (low width relative to length). Low aspect ratios also minimize the impact of the leading edge on L/D. This synergy combined with excellent compatibility of the surfaces for mounting solar panels results in a chain reaction of benefits.
Figure 6 illustrates towed platforms without fuselage components. In these configurations, solar panels and thin battery components can be distributed along the surface in a manner where, on a local basis, weight balances lift. These platforms can be made at large scales where edge effects are negligible. They may be deployed and recovered in flight to overcome the stresses caused by gravity in the absence of lift during take-off and landing. When equipped with solar panels, these towed platforms would provide considerably more energy than needed for their 24/7 flight; that energy could be the energy source for essentially any lead aircraft. The solar panels would be above the clouds and at higher radiation levels than on Earth’s surface; this translates to low-cost energy.
Thus two approaches overcome lateral structural issues: 1) low aspect ratio wings and 2) distributed weight on the wings equal to the lift. Longitudinal robustness is achieved through flexibility.
These two approaches provide practical methods to double the L/D of aircraft and to provide essentially boundless energy for aircraft in 24/7 flight. Aircraft in 24/7 flight could provide energy to other aircraft in flight; which extends the ability to use low-cost solar power to essentially any aircraft. The technologies enable a new era in aviation where the aircraft have both low-cost energy and high speeds. Ultimately, these aircraft are capable of being more cost effective than train, ship, bus, and truck transit for all routes past a local threshold distance.
Overcoming Pitch Instability – A widely-applicable application of a flat plate airfoil is to convert the upper surface of an aircraft to a lift generating surfaces, such as illustrated by Figure 5. Doing this on upper and lower surfaces may potentially double the lift on an aircraft with minimal increase in drag. While this may create new challenges for maintaining cabin pressure at high altitudes, there are many applications for drone aircraft and air taxis where pressure is not a factor.
An issue presented by the Figure 5 design configuration is the sudden change of lift from positive to negative as air’s angle of attack goes from 1° to -1°. At -1°, the negative lift and weight combine to cause a rapid nosedive, creating high instability to steady flight. The flat top of the aircraft is the cause of the instability, and essentially any traditional control surface would be too small to maintain stability.
A series of patents by G. Suppes provide solutions to this instability. The “Towed Platform” configuration is a lead delta wing aircraft pulling a platform, a hinge joint provides stability through adding flexibility to the design. Figure 6 illustrates such an aircraft. For the towed platform, a negative lift from a dip in the delta wing front results in a pivot action about the hinge joint and a return to positive air angles of attack; it is inherently stable, unlike the rigid structure. Figure 7 illustrates how lift torque and load torque passively actuate to equal and opposite values for passive stability.
Also, a contiguous and streamlined connection of a Towed Platform to a lead aircraft does not introduce form drag from a new front edge. This allows for incremental expansion of the capabilities of the lead aircraft, one of which is the addition of a large surface area for solar energy collection where the Towed Platform provides considerably more power than is needed to tow the platform.
Ultra-Light Weight Configurations – As a flat plate airfoil, the structure of the airfoil may be a single-layer thin canvas or board between support structures. This approach allows for ultra-light weight construction; construction that has less weight per area than can be achieved with a traditional airfoil.
When upper and lower surfaces of a fuselage may be configured to operate as flat plate surfaces, lateral extensions from the fuselage sides can be made with minimal weight penalty.
Overcoming Low Structural Strength – To overcome structural requirements of wings, the flat plate airfoil of Figure 5 has a very low aspect ratio (low width relative to length). Low aspect ratios also minimize the impact of the leading edge on L/D. This synergy combined with excellent compatibility of the surfaces for mounting solar panels results in a chain reaction of benefits.
Figure 6 illustrates towed platforms without fuselage components. In these configurations, solar panels and thin battery components can be distributed along the surface in a manner where, on a local basis, weight balances lift. These platforms can be made at large scales where edge effects are negligible. They may be deployed and recovered in flight to overcome the stresses caused by gravity in the absence of lift during take-off and landing. When equipped with solar panels, these towed platforms would provide considerably more energy than needed for their 24/7 flight; that energy could be the energy source for essentially any lead aircraft. The solar panels would be above the clouds and at higher radiation levels than on Earth’s surface; this translates to low-cost energy.
Thus two approaches overcome lateral structural issues: 1) low aspect ratio wings and 2) distributed weight on the wings equal to the lift. Longitudinal robustness is achieved through flexibility.
These two approaches provide practical methods to double the L/D of aircraft and to provide essentially boundless energy for aircraft in 24/7 flight. Aircraft in 24/7 flight could provide energy to other aircraft in flight; which extends the ability to use low-cost solar power to essentially any aircraft. The technologies enable a new era in aviation where the aircraft have both low-cost energy and high speeds. Ultimately, these aircraft are capable of being more cost effective than train, ship, bus, and truck transit for all routes past a local threshold distance.