Boxwing Designs: Synergy Copies?

Operators Rating
Lockheed boxwing jet

The Lockheed Boxwing as featured in the May 2012 issue of Popular Science.

Several followers have written to ask about the Lockheed Boxwing: an older design which, like a lot of other non-planar configurations, has seen new attention since the debut of Synergy. (For instance, in an article in the May 2012 Popular Science.)

Some have actually wondered whether they are ‘trying to copy Synergy’ now, or what the implications are for designs that would appear to be similar. So while I babysit the vacuum pump, I thought I’d finish up an overview on the subject as requested.

First of all, we are dealing with a topic having immense commercial value when you get it right. According to CEAS/DragNet 2000, a 1% reduction in drag on an Airbus 340 in long range mode will save 106,000 gallons of fuel per year, per aircraft. In the PopSci article, Lockheed projects a 40 percent savings in fuel cost.

A box wing aircraft can dramatically reduce the kind of drag caused by being heavier than air and having a finite wingspan. This kind of drag is called induced drag. When we reduce our ‘weight per wingspan’, or fight the result (wake vortices) using 3-D geometries, such as winglets etc., we obtain major cumulative benefits in climb and cruise that pay off in less fuel (meaning less weight) and better performance at altitude (more speed, meaning less fuel yet again due to shorter flight duration).

Boxwings, joined wings, diamond wings, and so on have been around for ages, but they all have major shortcomings that limit their further progress. One of these is that they tend to be (a lot) less stable. A consequence of that instability, and its physical causes, is that these designs may even add to total drag, rather than reduce it, after all the electronic and/or aerodynamic bandaids are placed on the stability problem. Due to certain kinds of analytical blindness afflicting the corporate design process, this obvious yet hidden cost sometimes isn’t grasped by puzzled reviewers until far too late.

A bigger problem is that most boxwings don’t behave themselves when forced outside of the usual flight envelope. Extreme stall departures and unrecoverable spins have been closely associated with such designs.

And finally, box wings look strong, but the same powerful forces that can flex wings up and down in turbulence are actually merely ‘concentrated into the corners of the box’. Consider the simple geometry of a parallelogram, with one side shifted powerfully upward, to reveal how boxwings actually increase stress concentrations (!) as both wings try to fold their two highly stressed corner joints in the same direction under aerodynamic loading.

This fundamental boxwing design limitation keeps the wings from actually bracing one another much- but it does create a major liability. (Joined wings and diamond wings, on the other hand, which connect at the tips in a more ‘structurally-appropriate’ triangle, offer no induced drag reduction…yet a ton of interference drag at the connection. So why bother?)

In contrast, Synergy’s patented boxtail technologies (USP No. 8,657,226) provide stability, control, and interference drag reduction in an aerodynamically and structurally beneficial way. This is a profoundly useful new development and a vast improvement over all the prior art. The span efficiency of designs in this category can reach parity with a box wing design in terms of induced drag reduction, but without the instabilities caused by a tandem, two-lifting-wings condition.

Configuration studies have shown that the least total drag for an aircraft occurs when a tail is somewhere behind the wings, pushing downward to provide longitudinal stability. Synergy is a tail-behind-wing configuration, in which the tails are specifically above and behind the wingtips, so that their stabilization function can further serve by acting against the intensity of the wake vortex.

Since Synergy became public, people around the world have been trying out various features of the design, and many have now seen how, if you do the opposite of what everyone has taught to this point, in accord with my invention, a new class of unusually capable aircraft can result. The above is a big part of why the US Patent and Trademark Office, in careful consideration of every prior boxwing technology worldwide, recognized the major distinctions between my boxtail (TM) configurations and all the designs that have come before… by granting the first of my pending patent applications on Feb. 25, 2014.

Prior to that point, companies haven’t had access to detailed specification of this teaching, and to their credit, they have been very careful and respectful about not showing off their derivative aircraft designs that might try to apply this breakthrough, at least not in public. (Others have offered a peek at potential DBT versions, sans tails…. message received!)

patented double boxtail aircraft design

A patented double boxtail aircraft design.

Even now that the patented technology is available for license, licensees will often prefer to develop their boxtail aircraft privately. That is what Synergy Aircraft did, for example, by securing as much development opportunity as any startup could possibly exploit in this industry, with room for yet more. Established companies with established markets are in a much better position, however, to bring other embodiments to fruition.

Like a lot of companies, Lockheed began investigating non-planar wing designs (joined wings and boxwings, specifically) decades ago. The Boxwing airliner featured recently is actually very old news that fizzled- probably for the reasons above.

It is possible, though (in fact, implied in certain foreign press articles) that its latest return derives from a simple what-if analysis: What if our old Boxwing was done up like Synergy, as a Box Tail?

As an aircraft designer who did that comparison several times, I KNOW what happens next. Excitement! Sleep becomes a very foreign idea for a while! Of course, we thought of the things a boxwing design might try to do or to claim in an attempt to evolve toward the specific teaching of my published and pending patent applications, and that door hasn’t been left open.

Some companies will naturally try to position themselves apart from the protected IP, by claiming this or that, but it really won’t work out. There is too much at stake and too much to be gained by protecting the granted patents, which is a process that doesn’t require me to be the bad guy. Treble damages pay for the effort rather well.

You see, not even a model airplane company should gamble their resources developing aircraft that profit from this detailed, fundamental teaching without looking into licensing of the patent, which obviously has to offer a highly desirable value, and low upfront costs, if it is to proliferate.

patented boxtail aircraft

A patented boxtail aircraft design.

We want that to happen for the good of society, so right now it’s available on the friendliest of terms. Yes, it might pay off someday, but aircraft take so much time and money to reach profitability, patents tend to be a bit irrelevant in the end unless you really work for it. As I’ve said many times, regardless of my development of the Synergy embodiment, the objective is to bring this technology to every application that can benefit from it, not to ‘sit around and wait for a chance to sue somebody,’ like most major patent holders do, or sell it without regard for the outcome, like those who are only in it for themselves and the money.

But you can see why it makes financial sense for greedy patent trolls to go after deep pockets corporations: under US Patent law, an infringing company can be held liable for three times as much money as they made from the sale of an infringing product! Waiting to ‘pop out from under the bridge and sue an infringer’ is a lucrative way to make serious money, especially in aviation, and it’s far easier than what I’m doing, I can assure you.

It costs a king’s ransom to develop an airplane- any airplane- and that is why the value of an aircraft patent to its inventor will be competing with development costs until after a company has spent the time and capital to create good products first.

So no: Neither Lockheed, nor Boeing, nor anyone else is going to run the risk of committing major funds to a development program without the necessary green lights from legal.

By far: the cheapest, simplest, and fastest solution for a company to reap the enormous benefits of this invention is to obtain a license to the technology and go for it while none of their competitors have any say in things. As things develop over time, the IP and legal landscape can change dramatically. For example, when and if other pending patent applications are granted, licensed, or sold.

Update, October 2016: I received official Notice of Allowance that a second, related patent has been granted: Aircraft Stability and Efficient Control Through Induced Drag Reduction. -John McGinnis

Categories: Q&A


  • Steve Marvin
    December 7, 2014 at 7:24 pm Reply

    I have been following Synergy for about a year and a half, and am interested in finding out if it will be made a homebuilt kit? If not why not? I’m just asking. Thanks.

    • Synergy Aircraft
      December 11, 2014 at 3:10 am Reply

      Yes, Synergy is intended to become an unusually easy-to-build kit aircraft in its earliest forms, and to grow through that process to eventually serve the certified market. Kit airplanes represent about half of the new aircraft completed each year (!) and they can be (and often are) a flying showcase of the most advanced technologies and safety features available. However, the process of reaching the market with any kind of aircraft will take far longer than most eager buyers are comfortable with. Kit planes have the advantage of an earlier, lower cost availability than a future commercially finished aircraft might have.

      Although newbie airplane companies sometimes rush off headlong into spending hundreds of millions of dollars in a race to certify processes and parts that aren’t even finalized, and shouldn’t be, it’s clear that the kit market provides the very best path to lower costs, lower risks, and a thoroughly refined product offering. By harvesting the collective brilliance of the industry’s most passionate craftsmen, engineers, businessmen, and aviators while operating profitably, our Synergy kit products will advance only the most proven concepts, methods and processes.

      Documenting everything necessary to speed the resulting FAA-friendly aircraft through to commercial certification still requires time and a stable process, which is why the positive cashflow and low risk exposure of the kit market supports higher growth toward mass production. During this time, relying on quick-return investors and customer deposits to fund such uncertain endeavors has a very clear business history in aviation: it’s always a mistake.

      An aircraft built from a kit can’t be used to make money or fly passengers for hire, but its owners can basically use it with the same and greater freedoms otherwise. However, due to Synergy’s economy, capabilities, and configurational potential, there is so much money to be made in its commercial applications that even the most aggressive routes to certification receive strong investor advocacy (despite the testimony of aviation’s difficult history.)

      Our tested plan navigates this business minefield not just from the start, but from long before there was the enabling breakthrough. Ultra-quality fast-build kit planes are the way to get started, and when the market wants so many of them that low cost and certification can be an industry-invested result with a reasonable timeline, everybody wins.

  • May 26, 2015 at 4:18 pm Reply

    Have you considered an ultralight (Part 103) version of the synergy aircraft? Does the Synergy Aircraft use flaps and if so what type?

    • John McGinnis
      June 12, 2015 at 7:12 am Reply

      Any sort of aircraft can be designed using the patented technologies Synergy Aircraft is exploring. Licensing opportunities are available from the patent owner. A Part 103 ultralight is on the wish list and in the works.

      Synergy Prime has what is called a split flap. It runs from boom tube to boom tube, across the wing center section. In a split flap design, only the lower wing surface hinges downward. The upper surface stays where it was. This type of flap adds more lift and more drag than a plain flap, and it offers other advantages for this aircraft as well.

  • Rodney Adams
    September 20, 2015 at 4:31 pm Reply

    Is there a full sized prototype of your aircraft flying yet?

    • John McGinnis
      October 7, 2015 at 6:05 am Reply

      There have been many prototypes flown, each one larger than the last. The one we are building now has room for one to six big people in it, and it will be the first man-rated prototype to fly and the first to explore the “high Reynolds numbers” and high speeds, where the more dramatic but more proven drag reduction methods apply.

      Ironically, it’s much harder to make a smaller aircraft fly well than a larger one, and we are pleased that all the novel configurational aspects and safety factors proved so outstanding in the smaller prototypes. To show the real reason we did all this, though, you have to go really really fast!

      • Jill McMullen-Falk
        December 14, 2015 at 4:49 am Reply

        Could you be more specific? What speed do you refer to as ” really, really fast”?

        • John McGinnis
          December 14, 2015 at 6:52 am Reply

          Sorry, it’s not advisable to say right now. The information can be inferred accurately by someone highly qualified, as there is enough information on our website to work it out, and certainly more than enough in the literature regarding the true opportunity space. However, the results of active drag reduction instantly start an argument among the average aero “experts”, who are comfortable and familiar with older, ‘closed systems’ of calculation, but ill-equipped to wade into open thermodynamics, where power changes the drag, not just the thrust. We don’t need to waste time defending specifications among naysayers. Some are so ‘out of their element’ that they think we’re talking about engine heat.

          We expect that pilots will be more than satisfied with its performance at a given horsepower: Synergy is fast enough to be a mystery if one has not done their homework.

  • Joseph Bolton
    September 12, 2016 at 3:17 am Reply

    Have any of the larger and well known aviation companies bought a license of this patented design? Just curious if anyone has even shown interest. I seldom see the laminar fuselage shapes let alone the whole enchilada of low drag designs Synergy is using all together. I’m beginning to suspect that the larger companies have too much tooling invested in tubular fuselages and too many sales people forcing the engineering departments to even get close to being innovative.

    • John McGinnis
      September 12, 2016 at 6:50 am Reply

      Patent licensing information is typically held in confidence by the parties to the transaction and probably won’t see much public discussion until a design is released. Synergy Prime is a design owned by Synergy Aircraft, but plenty of other DBT aircraft (and/or aircraft in need of other proprietary technologies) are possible without high speed laminar flow as a priority. Widespread interest exists in the configuration, especially for airframes having a direct path to market, such as UAVs, cropdusters, and bizjets. Generally a preliminary and/or academic inquiry is made once a commercial opportunity has been validated for conservative categories of aircraft. As mentioned in the overview above, developmental priorities come first. We can help potential licensees refine concepts away from common blunders, ahead of directing them to a license negotiation. As to your observation, the impact of elegant physics on the economics of flight are far too commercially valuable to ignore. Large companies approach the problem, not as a change requirement to the status quo, but as a new initiative entirely, with its own 20-year timelines.

  • Patrick Casey
    April 19, 2017 at 8:28 am Reply

    Do you have a DeltaHawk engine yet? I get no response from them about shipping engines. Might you use the Continental 220HP diesel?

    • John McGinnis
      April 29, 2017 at 11:33 pm Reply

      Patrick, yes, as a developmental partner with DeltaHawk we have an engine. We, like you, look forward to their certification and to receiving our production engine. Synergy is designed to fully exploit the unique advantages and wonderful performance of the valveless, liquid cooled DeltaHawk engine, but is also capable of using almost ANY engine thanks to its unique attributes for available size, weight, and location of engines. Each implementation requires unique cooling and integration requirements. We strongly recommend users discover why DeltaHawk is the one worth waiting for.

Leave a Comment