A California man has set a world speed record for RC aircraft by using an aerodynamic oddity to push his glider to 548 MPH. Spencer Lisenby used a technique called dynamic soaring to whip his heavily reinforced composite glider to almost Mach levels over a mountaintop near Los Angeles on Jan. 19. The Santa Anna winds were blowing at 65 MPH up the slope of Parker Mountain, setting up the correct conditions for dynamic soaring. By performing loops that exploit the boundary layers of the moving air, the pilot can use the energy of the wind to accelerate the aircraft to speeds much higher than the wind itself. With every loop, the action adds far more energy and speed to the aircraft than it loses in climbing back up the hill and the result is a head-snapping series of climbs and descents.

As Lisenby and other devotees of the extreme sport get into the transonic speed ranges, there are greater demands on the aircraft and technologies supporting them. The planes normally operate at 60 to 80 Gs and peak at 120 Gs. It’s also not for the faint of heart. “Every time you go out there and fly faster than you have before, you get this feeling like you’re in over your head, and your brain can’t stay ahead of what’s happening,” Lisenby told newatlas.com. “It’s a very difficult thing to keep up with. That’s the human factor of dynamic soaring. The faster we go, the faster we have to think.” 

Russ Niles
Russ Niles is Editor-in-Chief of AVweb. He has been a pilot for 30 years and joined AVweb 22 years ago. He and his wife Marni live in southern British Columbia where they also operate a small winery.

15 COMMENTS

  1. Is this too obvious or could the camera have simply been mounted on a tripod with the lens aimed at the center of the loops and zoom backed out a smidge to capture the whole thing without inducing vertigo in we viewers? Maybe it was a helmet cam ON the operator (who was neither the launcher nor the “man in black”) and thus conveys HIS experience !

    • Agree. Tripod mount with fixed FOV aimed at the top half of the loops would have been better. (Had to wait for nystagmus to subside before posting this…)

  2. Highly impressive that a model glider can sustain 80 – 120G. What materials were used? What were the development and build costs?

    • What folks are missing is that if the vehicle weighs mere ounces, the high G forces are easily accommodated by normal materials and building techniques.

  3. The camera work did exactly what the photographer set out to do. It graphically portrayed and demonstrated speed which along with lift vector, aerodynamics, materials, structure and skill is precisely what this story is about.

  4. They should make full scale aircraft out of that stuff. Then every landing will be great. Problem is the occupant can’t withstand 120 g’s.

  5. I searched everywhere within FAR 91.117 to find the sub-part which exempted RC gliders from the 250kt speed limit below 10K’ . I musta missed it ? While we’re at it, maybe they need a FAR for maximum G’s ?

    That video is like a Bárány chair with your eyes open. Either that or it’s still another subtle eye test?

    • Don’t see any need for max G’s.

      But I agree with your comment re: exemptions. It seems these days as if as long as you have a video to post on YouTube, anything is legal.

      But hey, rules are only for suckers, right?

    • I believe that it falls under an exemption for air racing and exhibitions.
      As far as Gs, every structure already has limits that the operator must be aware of.

    • You didn’t look hard enough. Google Docket No. FAA-2014-0396. Traditional model aircraft (not drones) have been exempted from the FARs as long as they fall within certain parameters (below 400 ft AGL, < 55 lbs, non-commercial use, etc.).

  6. Hard to believe without seeing the “no photoshop” video evidence.
    Was easily viewable on my 21″ desktop monitor.

  7. I’m sure several RC Aircraft have achieved that speed and have photographic evidence. Ground scars mostly.

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