60 tons at what RPM ?
MolaKule said:In terms of forces, for example, the RR RB211-535E4 fan had a 74" dia., a fan tip speed of 1500 ft/sec. Each 15-lb. blade was subjected to a centrifugal force of 60 tons!
Use Vbladetip = Omega*Radius, or 1500 ft./sec. = Omega*Radius, where Omega is the angular velocity in radians. Then use appropriate dimensions to solve for RPM.
Fan tip speeds and Turbine blade tip speeds are what we use in aerodynamic studies.
In the 1970s when Rolls-Royce developed the RB211 to compete against P&W for a Boeing contract as well as being sole-source power for the Lockheed TriStar it was developed with what was the world’s first carbon fiber fan blades. Those failed a required test for FAA/EAA certification. Rolls had to declare bankruptcy and the British government controlled them while they worked on a Ti replacement blade.I've been following this story for a while. How's this for a really oddball suggestion? I'm hearing one guy claiming that the only correct way for P&W to address this is to use composite fan blades similar to what's used in GE90 engines and that the titanium alloy blades are no longer acceptable in the application for safety reasons.
In the 1970s when Rolls-Royce developed the RB211 to compete against P&W for a Boeing contract as well as being sole-source power for the Lockheed TriStar it was developed with what was the world’s first carbon fiber fan blades. Those failed a required test for FAA/EAA certification. Rolls had to declare bankruptcy and the British government controlled them while they worked on a Ti replacement blade.
as for today, GE and Safran have the edge with carbon fan blades - Rolls is rumored to introduce them on a future development of the Trent series.
I believe that’s normal. This explains it as an “abradable shroud”. It’s supposed to have a tight fit.At time 13:30 it looks like the end of the blades are rubbing on the intake cowling. Is that normal ?
Use Vbladetip = Omega*Radius, or 1500 ft./sec. = Omega*Radius, where Omega is the angular velocity in radians. Then use appropriate dimensions to solve for RPM.
Fan tip speeds and Turbine blade tip speeds are what we use in aerodynamic studies.