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When will a diesel be available for my aircraft? |
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News, facts, and comments on the coming revolution for piston-engine aircraft.News of October 22, 2005Letter from the Bi-Rotor AutoGyro (BRAG) Group...We received this letter from Ben Mullett, Principal: "I am founder and technical director of The Bi-Rotor AutoGyro (B.R.A.G.) Group based near Bedford, UK. We have been running for over three years now, and anticipate using diesel power in some future designs for a number of reasons, all of which I re-discovered in a brief acquaintance with your excellent web site. We are working on the development of this BRAG configuration, which offers good efficiency for a rotorcraft due to the 2x higher aspect ratio of the rotor system - this brings a theoretical reduction in induced drag of 4x - we are seeing this repeatedly borne out in the power loadings at which we can fly our increasingly large models. The same simulations that predict our real model performance also predict a full scale 4-seater rotorcraft with near-VTOL capability that flies well on 135 bhp. The sims say it can cruise near 110 Kts using off-the-shelf components - no special rotor technology. Part of the path to this performance is the application of a small amount of power to the rotors - it allows them to fly with the rotor disk plane aligned to the direction of motion, and de-skills the rotor management. An autogyro tilts the rotor back to allow the air to power the rotor, a helicopter tilts the rotor forward to use it for propulsion, but we run the rotor as near flat as we can arrange, since there is in that area a regime where the rotor thrust vector is perpendicular to the direction of motion, and rotor thrust drag is zero. The BRAG configuration is also unusually stable, and both models and simulations have been successfully flown at the first attempt by pilots with no previous experience. They fly permanently in (assisted) auto-rotation, and can therefore offer severely short low speed landings after an engine-out. Your crystal ball predictions for GA rang several bells here! Our goal is to advance the state of the art to a stage where BRAG designs can be developed commercially in a range of applications. During this phase we are operating as a not-for-profit organisation using volunteers from around the world to further the work." posted at 10:26 AM |
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