Little and Large Extra Duo - Full Size Aerobatics with a 'Mirror' scale Radio Controlled model.

Описание: A full size Extra EA-300S, flown by Chris Burkett, does aerobatics in a 'mirror' routine with a large radio controlled scale model Extra, flown by Mike Williams. Filmed at Old Warden during the Shuttleworth Family Airtshow 2021.
Extra 300S Full-Size Aircraft
The aircraft Chris is flying is the Extra 300S, which is a lighter, higher performance single seat variant of the more common two seater, the Extra 300L. It was designed by Walter Extra, a German aerobatic pilot and engineer. His designs have rewritten what it is possible to do in an aerobatic plane. The carbon fibre wing spar is incredibly stiff and strong, designed to an ultimate failure load of 24g – at these stress levels the weakest point in the system is more likely to be the pilot!
The high strength and stiffness make it possible to fit enormous control surfaces – rudder and elevator have large maximum deflections, and the ailerons are almost full span. This gives eyeball popping roll rates of around 400 degrees per second - and even faster than this in 'snap' or 'flick' rolls.
Trying to improve upon the highly successful Pitts Special biplanes of the 1970's and early 1980's, Walter Extra soon concluded that the future of aerobatics lay with monoplanes, both because of the intrinsically higher performance available from an aircraft that did not have to carry external struts and bracing wires, and also due to the cleanness of the profile presented to the aerobatic judges during competition. His designs have evolved from the Extra 230 (4 cylinder engine, wooden wing), through the Extra 260 (6 cylinder engine, wooden wing), to the Extra 300 series of aircraft with their 300+hp six cylinder Lycoming engines and carbon fibre wings. The fuselage is of 'conventional' welded steel tube construction (good for 16g) and covered by glass fibre panels, with some fabric covering at the rear. Chris’ aeroplane was built in 2006 and was the last Extra 300S model produced.
The Extra 300S has placed highly in World Aerobatic Championships, and has been flown in the Red Bull air races by pilots such as Nigel Lamb, Paul Bonhomme and Peter Besenyei. Its latest evolution, the Extra 330SC, is flown by the current World Aerobatic Champion, Francois Le Vot.

The Model
Mike’s Extra 330SC is designed after its full-size counterpart by the Czech company Krill Aircraft. The airframe is fully composite, comprised largely of carbon fibre. The design has been tweaked in order to cope with demanding 3D manoeuvres which are now the norm for model freestyle flying. The wing planform copies the full-size, however the model features much larger ailerons both in chord and span. It also uses a significantly different aerofoil section. The leading edge is much sharper than full-size and this gives a much cleaner break into post-stall manoeuvres like the harrier.
One of the reasons Mike can do manoeuvres like the harrier (a deceleration in level flight into ultra-high angle of attack beyond 45 degrees) is because the model flies with much lower wing loading than full scale, which makes the 41% machine incredibly forgiving and allows Mike to get away with things that Chris can’t. It also results in a very impressive thrust to weight ratio of roughly 2.5:1, which in turn allows the model to prop-hang at between 30% and 50% throttle. Full power results in an impressive acceleration out of the prop-hang and vertical lines can be extended indefinitely or until out of sight.
Power is provided by a 175cc flat twin two-stroke MVVS petrol engine, where each cylinder feeds into its own tuned exhaust canister system. This not only controls engine noise but also provides more linear throttling characteristics. In order to perform extreme 3D manoeuvres the control surfaces have around 60 degrees of available movement and are fully utilised when 3D rates are on.
Freestyle flying isn’t just full-on 3D, it also incorporates smooth aerobatics at which the model also excels. There are, however, some manoeuvres which the full-size can perform that the model can’t replicate – mainly any manoeuvre which requires large amounts of gyroscopic force. With a lightweight carbon-fibre prop and lower inertia, the gyroscopic effect on the model is drastically reduced.
Overall the 41% scale Extra is incredibly forgiving – though like any aeroplane there are limits to its flight envelope which must be respected.

More info:- http://www.gforceaerobatics.com/wp-co...

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