The unorthodox five-place Synergy aircraft concept gained critical attention with its public introduction about one year ago and, as AVweb learned Thursday, itmay soon be taking another enterprising turn. Aircraft are generally designed to do one thing very well (high speed cruise, for example), often at the expense of other things (like fuel burn, slow flight, or landing speed and distances). Aerodynamically, that is where John McGinnis’ Synergy hopes to be different. It seeks to integrate into one highly efficient package multiple aerodynamic principles that McGinnis says aren’t often used together, or to their full effect. The designer has reason to be confident his aircraft succeeds in the task while bending to fewer compromises across the flight envelope. McGinnis told AVweb Thursday that his project’s progress, like most others, is funding-dependent and he has plans to take a new approach there, too, with an effort that could roll out next week.
McGinnis says he’ll be launching a Kickstarter.com campaign (until then, McGinnis is directing people to a facebook page for updates). Kickstarter is website that provides a forum to match entrepreneurs with funding. Essentially, it allows ideas to transform into funded projects with money from individual donors. For his next stage of funding, McGinnis has a clearly defined goal. McGinnis prefers not to spew specifications garnered from computer simulations or smaller scale flight tests to promote the Synergy. But the results he expects to prove in full-scale flight tests are significant. According to McGinnis, “A lot of times when you’re shooting for high performance or high efficiency, you wind up with an uncomfortable airplane that’s not very practical. Everything about this design keeps the priority on things that we need to address before more of the general public shares our enthusiasm for general aviation. Having said that, we’re light and fast, so the performance is definitely there.”
The Double Box Tail Configuration:
Catalyst for Efficiency
Half futuristic sailplane, half fighter jet, the roomy five-seat Synergy aircraft is the first example of an exciting new technology for fast, roomy, fuel efficient airplanes. Harmonizing six proven technologies for drag reduction at low cost, including Laminar Flow, Wake Propulsion, Open Thermodynamics, and Subsonic Area Ruling, Synergy achieves both high speed and low induced drag in a structurally robust, lightweight form.
Stability and control through induced drag reduction
The energy of wake vortex is created by heavier-than air flight, not by anything we design or put on an airplane, and it is 100% lost to us unless we can make use of it for something. In the 1970s Burt Rutan did so marvelously with the first-ever application of Whitcomb’s non-planar winglet technology. Being vertical stabilizers located behind the CG, Rutan winglets create yaw stability while reducing the energy of wake vortex.
After decades of study, I have discovered that the ideal place for a tail is connected to a wingtip by a tall, shared vertical winglet. In this location a deliberately strong negative lift from the tail can achieve its stabilizing action by reducing the strength of wake vortex, while constructively interacting with the other flight surfaces from the proper safe distance. Its downward force reduces wing bending moment, and in a swept wing design, counters wing twist.