The Electra had paddle-blade propellers and made the typical noise associated with those, exacerbated by high turbine power. All I might need to say is 'powerful enough to induce whirl-mode wing failure'...
Most of the noise inside the cabin was for seats forward of the wing. If I recall correctly the noise was relatively rich in discordant low frequencies.
I never asked anyone who might have flown Electras in passenger service whether they were noisy from the cockpit, but have read plenty of accounts that said they were (relative to other contemporary aircraft in the same general expected performance range).
schlimm Paul Milenkovic I asked an airline pilot who was in a position to know something about the L-188 you have pictured, known as the Lockheed Electra. "I have ridden on a twin-engine turboprop Convair, and that was loud -- is the Electra loud (in the cabin from prop noise)." "Is the Electra loud?" was the answer posed as a stupid question, "you have a twin-engine Convair . . . on each wing!" If he was an Eastern pilot, he must be pretty old now, or else a very young pilot when he flew Electras. Eastern last flew one in 1977. Perhaps he flew for some freight line later? My memory of flying twice on American to DC in the mid-60s was that it was very quiet compared to piston-engined planes.
Paul Milenkovic I asked an airline pilot who was in a position to know something about the L-188 you have pictured, known as the Lockheed Electra. "I have ridden on a twin-engine turboprop Convair, and that was loud -- is the Electra loud (in the cabin from prop noise)." "Is the Electra loud?" was the answer posed as a stupid question, "you have a twin-engine Convair . . . on each wing!"
If he was an Eastern pilot, he must be pretty old now, or else a very young pilot when he flew Electras. Eastern last flew one in 1977. Perhaps he flew for some freight line later? My memory of flying twice on American to DC in the mid-60s was that it was very quiet compared to piston-engined planes.
This was in 1986 -- I am older than many think.
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
flew on all these plains. Softest to loudest: Convair, Electra, DC-7, DC-6, Constilation. All except Convair noisier than a jet inside, but not outside.
Jets, noisiest to loudest: 747, DC-9, DC-8, 727, 707. 707 and Convair about equal. Earliest 707s a bit noisie.
RME Most of the noise inside the cabin was for seats forward of the wing. If I recall correctly the noise was relatively rich in discordant low frequencies.
The Airbus A320 treats the first-class cabin and flight deck to "propeller noise" from the turbofans that project forward from the wing. In a turbofan engine at takeoff or climb power, it is called "buzzsaw noise" because that is what it sounds like. We coach-class discount-fare Boarding Zone 3 peons in the back of the plane get a quieter ride.
Part of why I asked that question was that there was acoustics research interest in the prop-fan (Pratt and Whitney-Hamilton Standard) and unducted fan (General Electric) proposals for jet-engine speeds with propeller fuel economy. The question was whether such planes could be made quiet enough for acceptance by airline passengers accustomed to jets. In the research papers presented at the Acoustical Society of America, there was reference to the Viscount, a British turboprop, which was supposed to be remarkably quiet for a propeller aircraft on account of a serious effort to take acoustics into account in its design.
I also had occasion in the very late 1970s to visit an acoustic test chamber facility in connection with work that I was doing, and I asked the operators about sheet posted on their bulletin board describing the prop-fan -- this facility may have done some tests in support of that program. I was told, "A jet is Mach .86 but the airlines are slowing down to Mach .75 for fuel economy reasons, the prop-fan in Mach .7. Heck, a Lockheed Electra is Mach .6, instead of the prop-fan, why not just fly a bit slower and then you can use a Lockheed Electra."
Maybe a Lockheed Electra is just awfully noisy and unacceptable to many passengers? My recollection of the Convair 330 conversions to twin turboprops is the noise and vibration was so strong you think would lose dental fillings, and that one pilot told me an Electra was "a Convair on each wing." Is that why over 30 years later the prop-fan idea hasn't gone anywhere?
RMEThe Electra had paddle-blade propellers and made the typical noise associated with those, exacerbated by high turbine power. All I might need to say is 'powerful enough to induce whirl-mode wing failure'... Most of the noise inside the cabin was for seats forward of the wing. If I recall correctly the noise was relatively rich in discordant low frequencies.
Fortunately Lockheed learned from the early Electra disasters and later models along with the P-3 were quite rugged. Interesting that the latter didn't get the scimitar propeller as its C-130 cousin did. But I digress.
I flew in a Convair turboprop several times and did not find it that noisy, perhaps because the trips were short. In the jet age flying in a turboprop can be a novelty.
To tie this topic back to something railroad related, I can only speculate about the noise impact of running many turbojet powered trains if it became economically feasible. Those early jet engines were Loud; the loudest one I've heard by far was on a ROKAF C-123K - ear bleed noisy!
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Externally the loudest jets were the Viscount ( turbo prop & and Caravelle straight jet ) Know flight engineer who would go inside of concourse at ORD whenever UAL operated one into concourse "D". He could stand Electras because they had two speed engines running on low speed when taxiing. ~10,000 and 13200 RPMs
The noise along the prop plane of an Electra usually happend when scynorizing system did not operate properly. Same for Convair CV-580s ( reengined Convair CV-440 )
For reasons unknown when starting cold 3 bladed reciprocating engines such as connie the standard was to count about 15 blades before applying fuel. A real art to starting them as a 2 handed job to control mixture, starer safety switch, ignition booster, throttle, and primer so not to backfire engines. Always knew who the newbies were. By the way some long distance recips carried copious amounts of engine oil. ie CV-440s ( short haul ) carried 30 Gallons don't know what others carried.
MikeF90To tie this topic back to something railroad related, I can only speculate about the noise impact of running many turboshaft powered trains if it became economically feasible. Those early jet engines were Loud; the loudest one I've heard by far was on a ROKAF C-123K - ear bleed noisy!
Fixed that for you (not that you didn't know already!)
The engines in the UA Turbotrain were PT-6s. Those made a recognizable 'jet noise' but not at particularly high decibels, or with the kind of widespread diffusion of noise that an airborne engine driving a large propeller would produce. If there had been a problem with noise in service, I'd expect better exhaust silencing in the frequency bands of concern would have been used.
I can't speak to the French engines (Turbomeca?) although they couldn't have been as bad as the little dental drills used in turbojet aircraft like the Magister. That nasty shriek, even at low volume, would cure anyone from wanting increased passenger service.
The UP gas-turbine engines are NOT representative of what passenger turboshaft-powered trains would produce!
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