Dynamic and Regenerative Soaring – Perpetual Energy in Flight

Dean Sigler Electric Powerplants, Sustainable Aviation 3 Comments

Phil Barnes has an impressive set of credentials, and an even more impressive body of work.  Having seen three of his presentations at the Experimental Soaring Association’s Western Workshops, this writer can attest to the breadth and depth of his knowledge.

According to his biography, “Phil Barnes has a Master’s Degree in Aerospace Engineering from Cal Poly Pomona and a Bachelor’s Degree in Mechanical Engineering from the University of Arizona. He has 25-years of experience in the performance analysis and computer modeling of aerospace vehicles and subsystems at Northrop Grumman. Phil has authored technical papers on aerodynamics, gears, and flight mechanics.”

He now has his own web site, How Flies the Albatross, where readers can interact with the flight of the albatross in simulated dynamic soaring conditions, with mathematical explanations of a very high order.  Barnes took all the photographs of albatrosses in flight, and are another impressive facet of his abilities.

Another segment provides an “Aerodynamic and Artistic Study” of German jet fighters from World War II (still in draft form but pretty awe inspiring nonetheless), and a PowerPoint presentation on regenerative soaring, “Flight Without Fuel: Regenerative Soaring Theory.”  

Imagine a sailplane that self-launches using the battery power to its electric motor, but leaves its large propeller out in the breeze to regenerate energy and recharge itself.  At first glance this could be seen as another perpetual motion scheme, but Barnes provides a detailed mathematical proof that the sailplane could enjoy a net gain in energy during its flights, allowing unlimited time in the air.  He adds a solar option that would further increase the utility of the craft.

Barnes draws on Hermann Glauert’s seminal 1926 paper and Paul MacCready’s 1998 presentation, which introduced the idea “with caution.”  Literally throwing caution to the winds, Barnes investigates the possibilities that Glauert called a “windmill on an aeroplane,” and MacCready outlined as “regenerative soaring, where in concept, an aircraft would incorporate energy storage, a propeller, and a wind turbine, or dual-role machine thereof, to propel the aircraft and regenerate stored energy in updrafts.”  Examining the dynamic soaring of the albatross, we can see the similarities to what Barnes has in mind, and the cross-currents of his thinking.

Phil Barnes' regenerative soaring concept

 The idea of regeneration implies a motor/controller system that like an electric car’s regenerative braking, puts energy back into the batteries when the motor is not providing power for the airplane.  It would also require a highly efficient regenerative mode. 

He notes that solar panels collecting 150 Watts per square meter would allow extended flight, but only on a augmentation basis and not as a primary power source.

Knowledgeable readers can help him make this possible.  Explaining that he hopes to create a model-airplane sized demonstrator, he details his “wish list”:

 The system I’m searching for does this:

1) Advance the throttle for prop operation

2) Pull back the throttle for regeneration in updrafts and in final descent

     – same rotation direction for windprop, but with 30% lower RPM during regeneration

3) “Pinwheeling” (torque-free) mode with throttle in “neutral” position

4) Windprop with (preferably 8) high-pitch blades and symmetrical sections

      – as in my attached package 

5) Nice to have: Record altitude, airspeed, GPS coordinates, and battery current (+/-) as “flight-test data”

 His contact information is on the web site, exposure to which will inspire many grand ideas, some of which may provide feedback for Barnes’ grand project.

Comments 3

  1. I am the first to support anyone who wishes to push the envelope…
    but perpetual motion is closer to the truth…

    let’s do a thought experiment…

    The reason a glider stays in the air, or even climbs higher than its release point from the tow aircraft is that the pilot looks for, and TRIES hard to stay in, a “thermal” where the solarly heated rising air has more energy than what gravity and drag take away from the airplane… The idea of “unlimited” flight times is a word play on definitions.

    Sure, mathematically provable,… IF energy is being added to the wings/propellers via environmental inputs, then his using the prop to catch that energy is cool… BUT… and here’s the “perpetual” part of this motion deal… the plane has to STAY where the thermals are… (perpetually, so to speak). And, really, who needs to charge the batteries on “final desent”? When you get down at hopefully some glider friendly airport, you can pull out the giant extension cord and suck up electrical energy from some coal-fired/nuke/windmill/solar driven power grid.

    So, if you want to travel from point A to point B… and on that day/hour the atmospheric gods are working against you, then collecting energy that’s turning the regenerative prop, will only slow down the craft, with a probable drop in altitude and then require that the sun is shining brightly on the solar array and/or the lithium batteries are WAY beyond today’s energy densities, provided all of the juice in the batteries was not already sucked dry just climbing to altitude.

    Even MacCready would have keep his Solar Challenger “perpetually” in the sky if the area of his giant wing could generate enough power (they can’t) to BOTH climb to 100,000ft AND to charge a set of batteries sufficient to HOLD altitude until the sun HOPEFULLY comes up again, half a day later, and be at full strength for the whole day (most of the time, the sun is NOT directly over head, which would be the vector perpendicular to the plane of a flying wing)… Both the solar panels AND the bats are not there yet to give “unlimited” flight times. AND, here’s the kicker, if they were, we would not need “regenerative breaking”…

    Our dear friend, young Mr. Piccard, has to deal with these simple quantum mathematics if he wants to fly around the world non-stop, solar-electrically. As Bert Rutan said at this year’s EAA, if you are going to land every few days, why even try (he didn’t really say that, but that was his point during his speech).

    There are much better ways to push the limits of the future of aviation…
    and I hope Barnes focuses on them. I am with you bro, but you are working on the wrong end of the problem.

    The future of aviation is electric flight.. and that changes EVERYTHING.

  2. What if we used magnetic energy?
    According to the following video, the input is 80% less than the output.


    Then if we “use” 20% of the output to “recharge” the magnetic generator, wouldn’t that make it a perpetual energy generator?

    Simple math: 20kw input -> 100kw output : 20kw input (recharging) -> 80kw of energy to be used to “propel” the motor.

    I’m not sure cause I don’t know how this magnetic generator works, but seems to me that if what they claim in the video to be true, then… problem solved!

  3. Post

    (Editor’s Note: Be extremely wary when someone promises 80-percent more energy out than is put in. The best electric motors we know of are 97-98 percent efficient, and that’s at those motors’ best speeds and at just the right amperage and voltage. It’s still a slight loss. If products such as those shown here were even remotely plausible, there would be no need to find investors. The thing would be in terrific demand and we’d all be driving self-powered cars and living off the grid in grand style.)

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