View Full Version : RR HBPR Engines
avialuver33
24th Jul 2002, 00:52
Living as close to an airport (Buffalo/Niagara Int'l) as I do, and being an incurable airliner buff, I spend my fair share of time watching take-offs & approaches. The driving range I frequent lies directly under the final approach. I've gotten to the point where I am pretty accurate at identifying airliners by sound, before I can see them. JT8-powered airliners (727's & DC-9's) are a snap---they're the loudest ones around. I have to listen a bit harder to distinguish a Super 80 from a 737---the 80's are a tad louder. Two airliners that sound just about identical to me are the A319, and Fokker F-100. The RR engines have a sound all their own---a VERY distinctive, subdued whine. Are the RR engines on the F-100 & A319 both 3-shaft layouts? Is this what gives the Rolls engines such a mellow purr?
Mark 1
24th Jul 2002, 12:19
The RR Tay and all the RB211 family are 3 shaft engines (but not the IAE V2500). They will usually have a lower fan RPM than a 2-shaft engine as the fan speed is not compromised by having a smaller diameter LP compressor on the same shaft.
This usually means that the fan has a subsonic tip speed at approach power settings - typically 55-65%N1 - and will not be producing the 'buzz-saw' noise of a supersonic fan tip.
Maybe this is the difference that your hearing.
avialuver33
24th Jul 2002, 23:43
Mark I
Thanks for the reply. Is the V2500 one of the engines produced by the PW/RR collaboration? Is this the engine on the 717? I see lots of AirTran 717's coming & going---VERY quiet compared to the DC-9's they used to fly.
twistedenginestarter
25th Jul 2002, 09:48
The 717 uses the two shaft RR BR 715. I would guess you are just comparing older engines with newer ones.
canberra
27th Jul 2002, 14:25
ever heard a rolls royce car? thats why the aero engines are also so quiet, understated- just like the english!
Sorry Canberra,
Rolls Royce cars are now owned by BMW; building a new factory down near Chichester. The factory at Crewe is now owned by VAG (VW Audi) and soon to stop building RR's and concentrating of Bentley's.
spekesoftly
27th Jul 2002, 22:21
Let's hope that BMW's ownership of Rolls Royce doesn't end like the Rover debacle!!
Have flown with RR engines for over twenty five years...the best in the business, IMHO.:)