Work On Composite Fan Blades For Rolls UltraFan Demonstrator Begins
SINGAPORE—Production of the composite blade set for Rolls-Royce’s UltraFan future large civil engine family demonstrator is getting underway at the company’s Bristol facility, representing the official start of parts manufacturing for the first test engine.
When complete, the fan blade set will measure 140-in. in diameter, making the UltraFan the largest aircraft engine yet made in terms of physical dimensions. The largest engine currently, both in terms of dimensions and demonstrated thrust, is General Electric’s 134-in. diameter GE9X turbofan developed for the Boeing 777X.
The UltraFan demonstrator is due to begin ground tests in 2021 and will later be flown under the wing of a former Qantas Boeing 747-400. The aircraft is currently being converted into a flying testbed for Rolls by Washington-based AeroTEC and will be used to evaluate the high bypass engine in association with Airbus under a co-funded European Union Clean Sky 2 aerospace research program announced in 2018.
Although currently without a specific application, the geared UltraFan is designed to be scaleable for thrust sizes ranging from narrowbody engines in the 25,000 lb. thrust bracket up to the 100,000 lb. thrust size of current large twinjets. Early applications include potential re-engined A350 and 787 projects thought to be under study by Airbus and Boeing respectively, as well as all-new single and twin-aisle designs from the two major aircraft manufacturers. Rolls says the UltraFan will be available by the end of the decade, though it has previously mentioned 2027 as a possible target year for entry-into-service.
Assembly of the first blades comes around one year after Rolls began ground tests of a modified Trent 1000 with both the fan blades and fan case made from composites. The tests, conducted at the company’s Derby, UK facility, formed the finale of the Advanced Low-Pressure System (ALPS) technology demonstration program which paved the way for the UltraFan blade design.
The ALPS program, which also included flight tests of a blade set on a modified Trent 1000 on Rolls’ current 747 testbed, is a partnership between Rolls, Clean Sky, Innovate UK, the UK government’s Department for Business, Energy & Industrial Strategy, the UK Aerospace Technology Institute, ITP Aero and GKN.
The UltraFan/ALPS blades are also the first large scale carbon fiber-reinforced plastic units developed by Rolls since an experimental composite design tested for the RB.211 in the late 1960s. However, these first-generation blades were abandoned after they failed impact damage tests, forcing Rolls to fall back on a solid titanium blade design. It subsequently developed technology for a successful hollow-fan design which it has continued to perfect ever since and still uses to the present day.