Tipped off by Eric and his friends in Slovenia, I decided to make the short trip to Friedrichshafen, Germany, a mere 2 hours by train, boat and bus from Zurich.
On the boat from Romanshorn, Switzerland, to Friedrichshafen, Germany. About 7:30 am.
I started out and stayed in the B-side of the Exhibition, whose focus was on light aircraft and components for light aircraft, and the electric flight forum. I very much enjoyed the exhibits at the stands of Stemme sailplanes, Pipistrel Aircraft, and Woopy Aircraft.
The Woopy Prototype stands in front of a delta hang glider of the same color scheme.
Pipistrel Aircraft’s stand was impressive, and transported to Friedrichshafen on only 3 trucks!.
“Sweet, this airplane includes two girls in the part’s list!”
The A-side of the exhibition was less technical and more consumer oriented, although the aircraft canopy manufacturers had their stands there. I went directly outside to see the Zeppelin. Inside the Zeppelin hangar I was greeted by a half-inflated blimp whose fins were all dismantled. Looked quite dilapidated but also informative to see the ballonets and support cablery. (nice word, eh)
The imposing hangar of the Zeppelin NT.
The not-so imposing resident of the hangar of the Zeppelin NT, a dying blimp.
The amputated stump where a horizontal stabilizer should have been.
Zeppelin NT did have an exhibit of their own within the hangar, next to that blimp. They had some hands-on exhibits, like an example of their helium valve, as well as a plaque declaring the unique aspects of their operation:
Zeppelin is the onliest to own a commercial passenger carrying certification.
I then walked out of the hangar and was able to witness the Zeppelin land or at least approach for a landing. I was disappointed at the amount of noise emitted by this lighter-than-air aircraft. The whole reason for flying with an airship is, in my opinion, to approximate the Peter Pan Flight in terms of silence, maneuvrability and legerity. Zeppelin’s approach reminded me of that of a 90m helicopter. See and listen for yourself.
It’s been a calm period here at Vintage Hang Gliders, but things will pick up soon. Easter was spent at the Headquarters of Solar-Flight in Slovenia. Solar-Flight is the brainchild of Eric Raymond, who has built and flown the first truly practicable solar aircraft. We travelled to the town of Radovljica in the night-train from Zurich.
The owner of the company, Eric Raymond, is a Hang-Glider Pilot and Aeronautical Engineer. I’d already had the chance to talk with Eric about his airship plans. This purpose of this trip was to visit an entrepreneurial Aero Engineer in his workshop, to talk about lightweight aircraft and also to see the progress he’s made in producing the two-seater version of his Sunseeker aircraft.
Interior of Sunseeker III, a Solar Stemme.
Engine and Fairing Mockup of Sunseeker III, the propeller and dorsal fin assembled by me according to Eric’s Concept.
It was my first chance to see the Sunseeker II up-close.
The powerplant-wing of the Sunseeker II, which contains (in-flight) both the solar-cells and the batteries needed to propel the aircraft and power it’s avionics.
The compact cockpit of the Sunseeker II, including pilot parachute and “Experimental” stamp to fend off the authorities.
I really got the sense of the lightness of the Sunseeker II. The original parent design is the Musculair, a German human-powered aircraft weighing only 25kg. In order to reduce drag, the control surfaces are controlled using a system built inside of the wing:
On the day of my visit Eric was holding a gathering to present his Sunseeker III, and among the guests at this gathering was Andrej Pecjak, who builds electric automobiles (among other activities). Andrej recently converted a Mazda RX8 to completely electric drive and I had the chance to drive it! It was incredible. Internal combustion’s days are truly numbered! The performance of the electrified car matches that of the petrol burning original, and it is really easier to drive than a gear-shifting, stallable petrol burner (although Andrej informs that it is possible to stall the electric motor).
At the wheel of an electric car.
Looking ragtag from my previous night in the overnight train (<4h sleep)
It was really impressive the amount of lightweight aviation enthusiasts were on hand (in Slovenia) and the interest in renewables and electric locomotion. I had been unaware about this scene existing in Slovenia, but it was a pleasant surprise. And our stay in northern Slovenia was very inspiring and rejuvenating in general.
At the end of the day, Eric brought out his weight-shifting trainer, whose name escapes me:
Eric rolls in his wheel with kids counterbalancing.
I’ve recently had the opportunity to chat with David Freund, a RC and Hang Glider Guru based in Los Angeles. I asked about lightening our glider by replacing hardware-store-grade turnbuckles and steel cable with lighter equivalents.
Spectra or vectran rope into thimbles with multi hole tangs
Check out the Sparrow Hawk control system for light control cables.
So, we got together to finish this glider as much as possible before I leave till the end of 09.
There is a noticeable warp in the wings. I now know how to correct that using the turnbuckles. A warped wing-cell, when viewed from the wing-tip inwards, resembles a trapezoid. Tightening the turnbuckles in the long diagonal of this trapezoid will remove warpage and irregularities which might cause flight instability.
Another essential improvement will be to replace that god-forsaken paper with ripstop nylon or silk. That paper is simply too fragile for reasonable handling conditions.
Thirdly, we see that the tail surfaces are way too small for the size of the wing box. These must be enhanced with actionable rudder, elevator and aileron surfaces.
Fourthly, we see that the tail-surfaces warp under the tension of the stabilizing cables. What does this say to this “seasoned vintage hang glider engineer” (hahahahahaha) ? That we must install counteracting wires to the warp in the tail surfaces to render them flat.
The flight day was started too late, the sun was setting, the wind was waning, but also, now that i notice it in the videos, the tail was supported a bit high. Supporting the tail lower might have increased the incidence angle which the wings “saw”, hence increasing their lift (and potentially putting the craft into stall at lift-off). How could we have seen this while trying in the dark?.