Two Ways to Haul 19 on H2

Dean Sigler Announcements, Electric Powerplants, Fuel Cells, Hydrogen Fuel, Sustainable Aviation Leave a Comment

Pipistel and Delft Technical University have introduced hydrogen (H2) powered, 19-seat airliners for the intermediate-range market.  Both are unique configurations with unique propulsion concepts.  Both attempt to lower drag through the use of their propulsive systems. Pipistrel Miniliner Pipistrel announced their Miniliner concept as a response to a “significant market potential” for a “zero-emission airplane in the 20-seat size class, capable of operating quietly from runways shorter than 1 [kilometer], including grass airstrips at small aerodromes.”  Seen as a disruptive element in providing service to currently unserved areas within a 200 to 1,000 kilometer (124 to 620 mile) range, the Miniliner could also serve as a microfeeder craft between small airports and large hubs. Although Pipistrel is somewhat mum about the internal and powerplant details for the craft, the propeller locations seem to indicate a major effort to reduce drag and eliminate wingtip vortices.  The tail, for instance, is very much what Bruce Carmichael, a proponent of laminar-flow designs, proposed …

UAVs Push Endurance Limits

Dean Sigler Diesel Powerplants, Electric Powerplants, Solar Power, Sustainable Aviation Leave a Comment

Three unpiloted aerial vehicles of wildly different configurations recently set endurance marks, each a “personal best,” with some achieving world records.  The varying designs show what can be achieved by careful aerodynamic design and efficient powerplants. Aerovel Flexrotor Sets VTOL Endurance Mark Not just a fair weather UAV, Aerovel’s unmanned Flexrotor, named for the sea nymph Actaea, “lifted off into a grey and rainy morning with 7.5 kilograms (16.5 pounds) of fuel onboard”.  According to the company, “It transitioned from hover to wing-borne flight, and soldiered on through a showery day, a blustery night, and then another day in the breezy and unsettled air behind a cold front. As dusk fell it transitioned back to hover, and dropped gently down onto a 12-foot square helideck underway at 8 [knots] (9.2 mph). Time from launch had been 32 hours and 8 minutes. More than 3 hours’ worth of gasoline remained in the tank.” The press release doesn’t say where the flight took …

Not a Goldschmied Fuselage, but Still Wonderfully Low Drag

Dean Sigler Electric Aircraft Components, Electric Powerplants, Sustainable Aviation Leave a Comment

Following your editor’s blog entry on the Prandtl wing and erroneously named Goldschmied fuselage, he received this correction from Dr. Brien Seeley, President of the Sustainable Aviation Foundation and one of the creators of the body in question. “However, it is, I think, important to note:  We did not fabricate a Goldschmied body and it is incorrect to refer to ours as one. Ours is original, unique and it does not at all rely upon Goldschmied’s annual suction approach (aft boundary layer treatment). A Goldschmied body studied at Cal Poly is shown along with a link to its 205 page study.  It differs by having a pointed nose and sharp convergence at the rear annular inlet to create the concave internal diffuser. To gain a better idea of what a real Goldschmied body is, your editor reviewed the thesis by a Cal Poly graduate student that details his efforts to test Fabio Goldschmied’s claims for his radical fuselage design.  Dr. …

The Man Who Made This Blog Possible

Dean Sigler Electric Powerplants, Sustainable Aviation 4 Comments

Your editor received this sad announcement yesterday from Andy Kecskes, editor of the Sailplane Builder newsletter, forwarded from Murry Rozansky, President of the Experimental Soaring Association. “Bruce Carmichael passed peacefully with his family by his side on Tues. I am glad that our and the other soaring organizations honored his contributions before this sad event. Bruce was 91+years old, an accomplishment in itself.  There will be a celebration of Bruce’s life on Sat. Aug. 15th at 10:30 am at Palisade’s Methodist Church, 27002 Camino de Estrella, Capistrano Beach, CA.  Reception to follow services.”  Please RSVP to; georgianatives@yahoo.com.” Bruce was a pioneer in low-Reynolds number aerodynamics, and had been influential in the design of many record-breaking and visionary aircraft.  He is listed as part of the team on Solar-Flight’s web page, performed a detailed design analysis and drag breakdown on Mike Arnold’s record-breaking AR-5, and was inspiration for many designers to explore the new realm of microlift, a low-speed, high-lift concept that …