Are Three Wings Better Than One?
The old proverb of “may you live in interesting times” has never been more accurate as it is today. We live in a time where various types of propulsion are being experimented with, most notably hydrogen and electric-driven aircraft. The world is seeing a limited but growing use of biofuels in aircraft. Passenger-carrying drones, offering a type of Uber-of-the-skies service, are nearly a reality. Various kinds of lightweight materials are being incorporated into airframes. No one thinks twice about using their cell phones or tablets on most flights anymore, it is simply a given.
So, the subsequent logical development regarding aircraft is finding ways to upgrade the current base of aircraft design. It can be argued that, in general, not much has profoundly changed in ~60+ years regarding a fuselage and one set of wings. A startup company named SE Aeronautics in Birmingham, Alabama is addressing that with a three-wing widebody airliner concept that was recently announced.
SE Aeronautics is working on a new generation widebody airliner concept, a 100% monocoque (an aircraft or vehicle structure in which the chassis is integral to the body) molded widebody airliner shown in Figure 1. According to Tyler Mathews, CEO and Co-Founder, they have begun conducting Computational Fluid Dynamic testing and simulation wind tunnel testing. Their goal is to have an actual prototype in three years (2024).
This aircraft christened the SE200, is being touted as a new super-efficient mid-market airliner that seeks to carry up to 264 passengers with a range of 10,560 miles. It is projected to reduce CO2 production by 80% as measured by per seat kilometer. The company claims that the SE200 will have a top speed of Mach .90 (690.5 mph), which is greater than other similar aircraft.
“Our innovative technology and new aircraft design will lower fuel consumption by 70% and lower CO2 emissions by 80% as measured by per seat kilometer. The innovative design is a more efficient, light-tri wing configuration that greatly improves lift over drag, resulting in short takeoff and landing (STOL) capabilities and extremely long flights. The construction is all-composite, molded in one tough, safer piece. We also incorporated super thin, long wings and complete streamlining from the nose to the tail. We did it all,” says Lloyd Weaver, Chief Engineer, SE Aeronautics, in a recent press release.
The short takeoff and landing potential increases the number of airports that can support this widebody, potentially opening new routes to secondary airports.
Due to the one-piece solid-molded fuselage that SE Aeronautics says will be several times stronger than existing aircraft designs, the lifespan of this aircraft will also be approximately double, up to 50 years. Conversely, this will reduce the block hour cost by half compared to similar existing aircraft, presumably due to the reduced maintenance needs in maintaining such an airframe and being manufactured in less than half of the time.
Figure 2 contains company-provided data on the aircraft.
The engines will be mounted on the rear of the aircraft. According to the company, this type of configuration provides better aircraft safety and efficiency. Aircraft with wing-mounted engines have a more challenging time maintaining control when one fails than rear-mounted engines.
Since the engines are not located on the wings, fuel will be stored on top of the fuselage in a self-sealing bladder.
“This aircraft will be the most practical, profitable, and permanent solution to the grossly underperforming airliner technology of today. Our manufacturing efficiency will allow us to produce our aircraft in significantly less time than the current traditional method. But the jewel in the crown is really our ability to get that fuel consumption rate down by 70%. We are going to revolutionize the industry,” according to a recent statement by Tyler Mathews, CEO, SE Aeronautics.
Another interesting selling point identified by the company is that cabin air is never recirculated due to a new “once-through” air feed ventilation system. In the time of COVID-19, which is being touted as something which may affect the world for years to come as it mutates, this is a novel selling point.
SE Aeronautics claims that this is the greenest aircraft coming to market and will support hydrogen or electric engine systems as well.
Their initial effort will be to offer an aircraft using conventional propulsion systems, using traditional jet fuel, and renewable biofuels. However, the company believes that the overall light manufacturing and high lift potential of the SE200 make the aircraft’s core design features best suited for progressive propulsion systems once they are a viable option. They expect to be able to support 100% electric within 4–5 years. In fact, they have already designed such an aircraft, which will be different structurally from the SE200 (due to battery storage), and this will be announced in the near future. SE Aeronautics does expect that battery technologies will take longer to mature, hence the estimated 4–5-year timeframe.
In a recent interview with Tyler Mathews, he stated that “We still have a few different design elements to work out, but essentially, we need a battery that is around 400–500 Wh/kg that has a few thousand cycles. Once that happens, we should be able to produce a 50-passenger all the way to 150-passenger 100% electric aircraft with a range of around 2,000 miles flying at an airspeed of 510 mph. As it stands, SE Aeronautics can completely revolutionize the aviation industry by bringing its conventionally fueled SE200 aircraft to market. Nothing new from the propulsion side needs to be developed. We just need to continue the detailed design, then build, test, and ultimately receive certification on the SE200. Once this happens, we can dramatically reduce the carbon footprint by a huge margin. That’s what aviation needs right now, and we can make this happen faster than anyone else on the planet. Our promise is that we will continue to innovate and provide the most efficient way to move the masses of people in this world. “SE” Stands for Super Efficient, and we aim to always be manufacturing the most viable Super Efficient aircraft.”
He also shared that discussions with several potential investors had taken place but have not moved forward with closing on any funding yet. SE Aeronautics has also been in talks with a number of suppliers for various systems and components, but due to the early stage of the effort, no decisions had been made on vendor selections. Potential customers have already been approached as well, but no comment could be made at this time.
The company added several engineers to focus on the CFD (Computational Fluid Dynamic) and various design aspects. They also have expectations on potentially partnering with a university for research purposes to supplement internal efforts.
History of Three-Surface Aircraft
In the early days of aviation, several aircraft types experimented with using some form of three wings or surfaces. None of these used three wings as the SE200, but “three-surface aircraft” consisted of a foreplane, a central wing, and a tailplane (source: Wikipedia).
The central wing surface provided the lift, and the other two surfaces provided some combination of lift, stability, or control. Military aircraft used a similar configuration (although only having one ‘true’ wing, along with two smaller surfaces) and have/had better maneuverability.
According to a Wikipedia post about this, “examples of reduced-area three-surface aircraft include the Piaggio P.180 Avanti, and the Scaled Composites Triumph and Catbird. These aircraft were designed to expose a minimum of total surface area to the slipstream, thus reducing surface drag for speed and fuel efficiency. Several reviews compare the Avanti’s top speed and service ceiling to that of lower-end jet aircraft and report significantly better fuel efficiency at cruise speed. Piaggio attributes this performance in part to the layout of the aircraft, claiming a 34% reduction in total wing area compared to a conventional layout.”
But none of the aircraft mentioned had a design with three wings as the SE200. Lighter materials and modern engine design have enabled this new proposed aircraft to build upon the legacy of other aircraft from earlier in aviation history.
One notable aircraft which had unswept wings (a single set) that surpassed Mach 1 was the Bell X-1 which Chuck Yeager flew to break the sound barrier for the first time ever. Of course, this plane was rocket-powered, so it had a wee bit more thrust.
No studies of a three-winged aircraft design (not three-surface) were readily available, so finding good research data to use in better analyzing this approach was not possible. We will need to await further information from SE Aeronautics as they announce their progress.
Finally
We truly live in an exciting era, where those who have the motivation, knowledge, and experience can push the cutting edge of possibilities further out. The early and mid-20th century were a golden era for aviation, but it seems that the early 21st century may challenge that. This is an exciting time for the industry with new types of fuels, engine technology, materials, electronics, communications, and novel aircraft designs.