US-12623778-B2 - Secondary airfoil apparatus, system, and method for improving lift and aerodynamic performance of a floatplane

US12623778B2US 12623778 B2US12623778 B2US 12623778B2US-12623778-B2

Abstract

The present disclosure relates to a secondary airfoil apparatus, system and method for improving lift, takeoff, landing and aerodynamic performance of a floatplane. The secondary airfoil is itself of sufficient structural rigidity to withstand any and all forces added by the airfoil during floatplane operation, and is fixedly attached between the floats of the floatplane. The secondary airfoil can be arranged at an optimal angle of incidence and vertical lift position relative to the primary airfoil, or wing of the aircraft, and relative to the floats center of gravity and drag for optimal maneuverability of the floatplane.

Inventors

Ronald A. Lueck
Michael Ryan

Assignees

Ronald A. Lueck
Michael Ryan

Dates

Publication Date: 20260512
Application Date: 20230822

Claims (15)

1 . A secondary airfoil apparatus for use on a floatplane, the floatplane including one or more primary airfoils and a pair of floats, the secondary airfoil apparatus comprising: an airfoil including a front end, a trailing end, and opposed exterior side surfaces, each exterior side surface adjacent to a float and having a length; and a plurality of pairs of attachment arms, each pair of attachment arms extending from the opposed exterior side surfaces and terminating at a respective pair of attachment points on the adjacent float, the plurality of pairs of attachment arms spaced along the lengths of the side surfaces.
2 . The secondary airfoil apparatus of claim 1 , wherein the opposed side surfaces are substantially planar and parallel to each other.
3 . The secondary airfoil apparatus of claim 1 , wherein each of the attachment points comprises an opening through which a bolt or rivet is placed to secure the secondary airfoil apparatus to a pair of floats.
4 . The secondary airfoil apparatus of claim 1 , further comprising a substantially watertight airfoil skin surrounding a plurality of ribs spaced from each other and extending substantially parallel to the opposed exterior side surfaces.
5 . The secondary airfoil apparatus of claim 4 , further comprising a cavity containing a collapsible fuel bladder.
6 . The secondary airfoil apparatus of claim 1 , further comprising an adjustable flap arranged on a trailing edge of the secondary airfoil apparatus.
7 . A system for improving lift and aerodynamic performance of a floatplane, the system comprising: a pair of spaced floats, each having an upper surface; a secondary airfoil; and a plurality of attachment arms, each attachment arm extending from an exterior side surface of the secondary airfoil and toward the adjacent float of the spaced floats for fixedly connecting the secondary airfoil to upper surfaces of the respective pair of spaced floats, the plurality of attachment arms being spaced along a length of the exterior side surfaces.
8 . The system of claim 7 , wherein the pair of mounting members each comprise a mounting member opening aligned with an attachment member opening arranged at the distal end within each of a pair of attachment arms.
9 . The system of claim 8 , further comprises a bolt or rivet extending through the mounting member opening and the attachment member opening.
10 . The system of claim 7 , wherein the secondary airfoil is configured vertically below a primary airfoil of the floatplane and horizontally between the pair of spaced floats.
11 . The system of claim 7 , wherein the secondary airfoil is configured within a center of lift secondary airfoil axis that is substantially orthogonal to an upper and lower outer surfaces of the secondary airfoil, and wherein the center of lift secondary airfoil axis is co-linear with a center of lift of a primary airfoil axis of a primary airfoil wing of the floatplane.
12 . The system of claim 7 , further comprises: a collapsible fuel bladder arranged within the secondary airfoil; and a fuel delivery system configured to deliver fuel from the fuel bladder to the floatplane.
13 . A method for improving lift and aerodynamic performance of a floatplane, the floatplane including a primary airfoil, a first float, and a second float, the method comprising: providing a secondary airfoil apparatus including: an airfoil including a front end, a trailing end, and opposed exterior side surfaces; and at least one attachment arms extending from the airfoil; and securing the at least one attachment arm of the secondary airfoil apparatus to upper surfaces of the first float and the second float, the securing comprising: connecting a mounting member to the upper surface of the float; connecting the at least one attachment arm to a sidewall surface of the secondary airfoil; and connecting the mounting member on the float to the attachment arm.
14 . The method of claim 13 , wherein the securing comprises: connecting a first set of mounting members to the upper surface of the first float; connecting a second set of mounting members to the upper surface of the second float; connecting a first set of attachment arms to a first sidewall surface of the secondary airfoil; connecting a second set of attachment arms to a second sidewall surface of the secondary airfoil; connecting the first set of mounting members to respective first set of attachment arms; and connecting the second set of mounting members to respective second set of attachment arms.
15 . The method of claim 13 , further comprising: inserting a collapsible fuel bladder within the secondary airfoil; and delivering fuel from the fuel bladder to the floatplane.

Description

PRIORITY CLAIM This application is a continuation of U.S. application Ser. No. 17/674,542 filed Feb. 17, 2022, which claims the benefit of priority of U.S. Provisional Application No. 63/150,422 filed on Feb. 17, 2021, the entireties of which are incorporated by reference. BACKGROUND This disclosure is generally directed to a secondary airfoil retrofitted to or integrated with an airplane having a pair of floats to improve lift and aerodynamic performance of the floatplane. More particularly, the disclosure is directed to an apparatus, system and method for more securely attaching the secondary airfoil to the pair of floats and utilizing the strength of the secondary airfoil itself to withstand forces that occur during takeoff, landing and maneuvering of the floatplane. Floatplanes, which include seaplanes and amphibious aircraft, generally include a pair of floats designed for takeoff and landing on water. The addition of a pair of floats beneath the floatplane can increase the weight of the aircraft. Aircraft are constrained by limits on their maximal loads, and the additional weight of floats limit payload and fuel capacity and can lengthen the takeoff distance. WO2017149196 discloses a floatplane including a fuselage, a primary wing, and a float arrangement including a number of floats, with an option of a third float directly under the fuselage. The two lateral floats are attached to the fuselage by secondary wing structures at an angle dependent on a height above the water needed for the propeller to clear the water. The secondary airfoils are not co-linear with the primary airfoil. The design does not provide a mechanism to add a secondary airfoil to current dual float seaplane designs. The airfoils are placed at an angle dependent on the height needed for a propeller to clear the water; this can be 45 to 60 degrees. This reduces the effective lift, which is orthogonal to the plane of the airfoil. This lift calculation is independent of ground effect, which serves to increase lift even further: vertical lift is 50% of the total lift generated at 45 degrees orientation, and 34% of total lift generated at 60 degrees orientation. By placing the airfoils at an angle, the height above water is increased, and therefore lift is decreased as compared to the present invention. US20060081732A1 discloses an airfoil that attaches to the spreader bars of a conventional two-float seaplane. The primary goal of the airfoil is to function as a faring over the spreader bars and thus reduce drag. A secondary effect of the airfoil is to generate lift. The airfoil is prevented from rotating as it generates lift. This design can be added on to any float configuration with spreader bars, although the airfoil is not attached to the floats. The height is set by the spreader bars and cannot be adjusted up or down to optimize ground effect or minimize water drag. In addition, the spreader bars are not designed to carry a radial load introduced by airfoil lift. The airfoil has very limited ability if at all to adjust angle of incidence since the airfoil is suspended by spreader bars in a fixed plane and this results in limitations on the lift of the airfoil especially at low airspeeds. The airfoil is not attached to the floats, which are designed to carry the entire load of the aircraft when landing and taking off, but are connected to the spreader bars, which are not designed to carry the load created by the secondary airfoil. When taking off, the full load is transferred from the wheels to the primary and secondary airfoils, and the secondary airfoil in the air only transmits a fraction of the load carried by the floats on the ground. Since the airfoil's attachment is determined by the location of the spreader bars, the position of the secondary airfoil is not adjustable along the longitudinal axis of the fuselage to allow the combined pitching moment of the primary and secondary airfoils to be balanced by the horizontal stabilizer and allow for stable aerodynamics. The position of the secondary airfoil cannot replace the function of the spreader bars to maintain the floats equidistant and thus allow elimination of a spreader bar and its drag. U.S. Pat. No. 1,512,912A discloses the use of an additional airfoil with a single or double float seaplane to allow retraction of the landing gear into an aerodynamic structure. With the airfoil inches away from the water above the waterline, it is not a practical solution in rough water. The position of the airfoil is determined by the location of the landing gear, not the center of lift of the primary airfoils. The lifting moment does not appear to be co-linear with the primary airfoils, indicating that there is lift but there is no ability to adjust the position to match primary airfoil center of lift. U.S. Pat. No. 1,816,130A discloses the addition of a fuel tank to the primary airfoil. The biplane configuration for a flying boat with small wing pontoons is used to stabilize the pla