What's the loudest GA aeroplane out there?
On the ground I suspect the Turbo commander and/or most turbo props with Garrett’s. However they are pretty quiet once they get going.
The QueenAir or the Aero Commander with the GTSIO640’s (I think that’s correct) would have to be right up there. Mind you I haven’t seen one of them flying for a few years now.
The QueenAir or the Aero Commander with the GTSIO640’s (I think that’s correct) would have to be right up there. Mind you I haven’t seen one of them flying for a few years now.
I remember living south of Essendon airport in the late eighties and being woken up by the southbound freighters. Often the Ipec DC9 and the Grand Commander from HBA would launch several minutes apart. The 9 would make an awful noise for about 20 seconds as it sped past but the Grand would be overhead for what seemed like hours, climbing out at 80 knots into a stiff southerly!!! Almost as noisy as the 9 but it lasted for ever.
Moderator
@e2_c
Argument over - the Britten Norman BN2-XL with acoustic lift has been proven the World's loudest GA aircraft. I am fortunate to have a copy of the demonstration flight, written by a prominent aviation reporter (RIP Paul):
Britten-Norman BN2-XL
By a well-known ‘Flight’ magazine Editor.
Undaunted by technical realities, the design team at Pilatus Britten - Norman has announced plans for the BN2-XL, promising more noise, reduced payload, a lower cruise speed, and increased pilot workload.
We spoke to Mr. Fred Gribble, former British Rail boilermaker, and now Chief Project Engineer. Fred was responsible for developing many original and creative design flaws in the service of his former employer, and will be incorporating these in the new BN2-XL technology under a licensing agreement. Fred reassured BN-2 pilots, however, that all fundamental design flaws of the original model had been retained. Further good news is that the XL version is available as a retrofit.
Among the new measures is that of locking the ailerons in the central position, following airborne and simulator tests which showed that whilst pilots of average strength were able to achieve up to 30 degrees of control wheel deflection, this produced no appreciable variation in the net flight of the aircraft. Thus the removal of costly and unnecessary linkages has been possible, and the rudder has been nominated as the primary directional control. In keeping with this new philosophy, but to retain commonality for crews’ transitioning to the XL, additional resistance to foot pressure has been built in to the rudder pedals to prevent over-controlling in gusty conditions (defined as those in which wind velocity exceeds 3 knots).
An outstanding feature of Islander technology has always been the adaptation of the O-540 engine which, when mounted in any other aircraft in the free world (except the Trislander) is known for its low vibration levels. The Islander adaptations cause it to shake and batter the airframe, gradually crystallise the main spar, desynchronise the accompanying engine, and simulate the sound of fifty skeletons fornicating in an aluminium dustbin. PBN will not disclose the technology they applied in preserving this effect in the XL but Mr. Gribble assures us it will be perpetrated in later models and sees it as a strong selling point. "After all, the Concorde makes a lot of noise" he said, "and look how fast that goes."
However design documents clandestinely recovered from the PBN shredder have solved a question that has puzzled aerodynamicists and pilots for many years, disclosing that it is actually noise which causes the BN2 to fly. The vibration set up by the engines, and amplified by the airframe, in turn causes the air molecules above the wing to oscillate at atomic frequency, reducing their density and creating lift. This can be demonstrated by sudden closure of the throttles, which causes the aircraft to fall from the sky. As a result, lift is proportional to noise, rather than speed, explaining amongst other things the aircraft's remarkable takeoff performance.
In the driver's cab (as Gribble describes it) ergonomic measures will ensure that long-term PBN pilots' deafness does not cause in-flight dozing. Orthopaedic surgeons have designed a cockpit layout and seat to maximise backache, en-route insomnia, chronic irritability, and terminal (post-flight) lethargy. Redesigned "bullworker" elastic aileron cables, now disconnected from the control surfaces, increase pilot workload and fitness. Special noise retention cabin lining is an innovation on the XL, and it is hoped in later models to develop cabin noise to a level which will enable pilots to relate ear-pain directly to engine power, eliminating the need for engine instruments altogether.
We were offered an opportunity to fly the XL at Britten-Norman's development facility, adjacent to the British Rail tearooms at Little Chortling. (The flight was originally to have been conducted at the Pilatus plant but aircraft of BN design are now prohibited from operating in Swiss airspace during avalanche season). For our mission profile, the XL was loaded with coal for a standard 100 N.M. trip with British Rail reserves, carrying one pilot and nine passengers to maximise discomfort. Passenger loading is unchanged, the normal under-wing protrusions inflicting serious lacerations on 71% of boarding passengers, and there was the usual confusion in selecting a door appropriate to the allocated seat. The facility for the clothing of embarking passengers to remove oil slicks from engine cowls during loading has been thoughtfully retained.
Start-up is standard, and taxiing, as in the BN2 is accomplished by brute force. Takeoff calculations called for a 250-decibel power setting, and the rotation force for the (neutral) C of G was calculated at 180 ft/lbs. of backpressure.
Initial warning of an engine failure during takeoff is provided by a reduction in vibration of the flight instrument panel. Complete seizure of one engine is indicated by the momentary illusion that the engines have suddenly and inexplicably become synchronised. Otherwise, identification of the failed engine is achieved by comparing the vibration levels of the windows on either side of the cabin. (Relative passenger pallor has been found to be an unreliable guide on many BN2 routes because of ethnic consideration).
Shortly after takeoff the XL's chief test pilot, Capt. Mike "Muscles" Mulligan demonstrated the extent to which modern aeronautical design has left the BN2 untouched; he simulated pilot incapacitation by slumping forward onto the control column, simultaneously applying full right rudder and bleeding from the ears. The XL, like its predecessor, demonstrated total control rigidity and continued undisturbed. Power was then reduced to 249 decibels for cruise, and we carried out some comparisons of actual flight performance with graph predictions. At 5000 ft and ISA, we achieved a vibration amplitude of 500 CPS and 240 decibels, for a fuel flow of 210 lb/hr, making the BN2-XL the most efficient converter of fuel to noise after the Titan rocket.
Exploring the Constant noise/Variable noise concepts, we found that in a VNE dive, vibration reached its design maximum at 1000 CPS, at which point the limiting factor is the emulsification of human tissue. The catatonic condition of long-term BN2 pilots is attributed to this syndrome, which commences in the cerebral cortex and spreads outwards. We asked Capt. Mulligan what he considered the outstanding features of the XL. He cupped his hand behind his ear and shouted "Whazzat?"
We returned to Britten-Norman convinced that the XL model retains the marque's most memorable features, whilst showing some significant and worthwhile regressions.
PBN are not, however, resting on their laurels. Plans are already advanced for the Trislander XL and noise tunnel testing has commenced. The basis of preliminary design and performance specifications is that lift increases as the square of the noise, and as the principle of acoustic lift is further developed, a later five-engined vertical take-off model is also a possibility."
All in all, a wonderful aeroplane.
Argument over - the Britten Norman BN2-XL with acoustic lift has been proven the World's loudest GA aircraft. I am fortunate to have a copy of the demonstration flight, written by a prominent aviation reporter (RIP Paul):
Britten-Norman BN2-XL
By a well-known ‘Flight’ magazine Editor.
Undaunted by technical realities, the design team at Pilatus Britten - Norman has announced plans for the BN2-XL, promising more noise, reduced payload, a lower cruise speed, and increased pilot workload.
We spoke to Mr. Fred Gribble, former British Rail boilermaker, and now Chief Project Engineer. Fred was responsible for developing many original and creative design flaws in the service of his former employer, and will be incorporating these in the new BN2-XL technology under a licensing agreement. Fred reassured BN-2 pilots, however, that all fundamental design flaws of the original model had been retained. Further good news is that the XL version is available as a retrofit.
Among the new measures is that of locking the ailerons in the central position, following airborne and simulator tests which showed that whilst pilots of average strength were able to achieve up to 30 degrees of control wheel deflection, this produced no appreciable variation in the net flight of the aircraft. Thus the removal of costly and unnecessary linkages has been possible, and the rudder has been nominated as the primary directional control. In keeping with this new philosophy, but to retain commonality for crews’ transitioning to the XL, additional resistance to foot pressure has been built in to the rudder pedals to prevent over-controlling in gusty conditions (defined as those in which wind velocity exceeds 3 knots).
An outstanding feature of Islander technology has always been the adaptation of the O-540 engine which, when mounted in any other aircraft in the free world (except the Trislander) is known for its low vibration levels. The Islander adaptations cause it to shake and batter the airframe, gradually crystallise the main spar, desynchronise the accompanying engine, and simulate the sound of fifty skeletons fornicating in an aluminium dustbin. PBN will not disclose the technology they applied in preserving this effect in the XL but Mr. Gribble assures us it will be perpetrated in later models and sees it as a strong selling point. "After all, the Concorde makes a lot of noise" he said, "and look how fast that goes."
However design documents clandestinely recovered from the PBN shredder have solved a question that has puzzled aerodynamicists and pilots for many years, disclosing that it is actually noise which causes the BN2 to fly. The vibration set up by the engines, and amplified by the airframe, in turn causes the air molecules above the wing to oscillate at atomic frequency, reducing their density and creating lift. This can be demonstrated by sudden closure of the throttles, which causes the aircraft to fall from the sky. As a result, lift is proportional to noise, rather than speed, explaining amongst other things the aircraft's remarkable takeoff performance.
In the driver's cab (as Gribble describes it) ergonomic measures will ensure that long-term PBN pilots' deafness does not cause in-flight dozing. Orthopaedic surgeons have designed a cockpit layout and seat to maximise backache, en-route insomnia, chronic irritability, and terminal (post-flight) lethargy. Redesigned "bullworker" elastic aileron cables, now disconnected from the control surfaces, increase pilot workload and fitness. Special noise retention cabin lining is an innovation on the XL, and it is hoped in later models to develop cabin noise to a level which will enable pilots to relate ear-pain directly to engine power, eliminating the need for engine instruments altogether.
We were offered an opportunity to fly the XL at Britten-Norman's development facility, adjacent to the British Rail tearooms at Little Chortling. (The flight was originally to have been conducted at the Pilatus plant but aircraft of BN design are now prohibited from operating in Swiss airspace during avalanche season). For our mission profile, the XL was loaded with coal for a standard 100 N.M. trip with British Rail reserves, carrying one pilot and nine passengers to maximise discomfort. Passenger loading is unchanged, the normal under-wing protrusions inflicting serious lacerations on 71% of boarding passengers, and there was the usual confusion in selecting a door appropriate to the allocated seat. The facility for the clothing of embarking passengers to remove oil slicks from engine cowls during loading has been thoughtfully retained.
Start-up is standard, and taxiing, as in the BN2 is accomplished by brute force. Takeoff calculations called for a 250-decibel power setting, and the rotation force for the (neutral) C of G was calculated at 180 ft/lbs. of backpressure.
Initial warning of an engine failure during takeoff is provided by a reduction in vibration of the flight instrument panel. Complete seizure of one engine is indicated by the momentary illusion that the engines have suddenly and inexplicably become synchronised. Otherwise, identification of the failed engine is achieved by comparing the vibration levels of the windows on either side of the cabin. (Relative passenger pallor has been found to be an unreliable guide on many BN2 routes because of ethnic consideration).
Shortly after takeoff the XL's chief test pilot, Capt. Mike "Muscles" Mulligan demonstrated the extent to which modern aeronautical design has left the BN2 untouched; he simulated pilot incapacitation by slumping forward onto the control column, simultaneously applying full right rudder and bleeding from the ears. The XL, like its predecessor, demonstrated total control rigidity and continued undisturbed. Power was then reduced to 249 decibels for cruise, and we carried out some comparisons of actual flight performance with graph predictions. At 5000 ft and ISA, we achieved a vibration amplitude of 500 CPS and 240 decibels, for a fuel flow of 210 lb/hr, making the BN2-XL the most efficient converter of fuel to noise after the Titan rocket.
Exploring the Constant noise/Variable noise concepts, we found that in a VNE dive, vibration reached its design maximum at 1000 CPS, at which point the limiting factor is the emulsification of human tissue. The catatonic condition of long-term BN2 pilots is attributed to this syndrome, which commences in the cerebral cortex and spreads outwards. We asked Capt. Mulligan what he considered the outstanding features of the XL. He cupped his hand behind his ear and shouted "Whazzat?"
We returned to Britten-Norman convinced that the XL model retains the marque's most memorable features, whilst showing some significant and worthwhile regressions.
PBN are not, however, resting on their laurels. Plans are already advanced for the Trislander XL and noise tunnel testing has commenced. The basis of preliminary design and performance specifications is that lift increases as the square of the noise, and as the principle of acoustic lift is further developed, a later five-engined vertical take-off model is also a possibility."
All in all, a wonderful aeroplane.
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@e2_c
Argument over - the Britten Norman BN2-XL with acoustic lift has been proven the World's loudest GA aircraft. I am fortunate to have a copy of the demonstration flight, written by a prominent aviation reporter (RIP Paul):
Argument over - the Britten Norman BN2-XL with acoustic lift has been proven the World's loudest GA aircraft. I am fortunate to have a copy of the demonstration flight, written by a prominent aviation reporter (RIP Paul):
I recall reading many years ago in a U.S. aviation magazine that the fly-over noise of a Queen Air at 5,000 ft. exceeded that of a B707! When the N.S.W. Govt. used Queen Airs as the Air Ambulance there used to be many complaints from the general public regarding the noise, especially outside of Mascot's normal curfew hours, I remember one caller on talk-back radio complaining about the noisy "military aircraft" being allowed to operate!
Last edited by zlin77; 17th Mar 2023 at 20:18.
The Queen Air didn't make noise - it made music!
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Still remember a Queenair taking off from YPLC at 0 Dark Hundred on many occasions and the Flight path taking it just past my Unit at North Shields. T'was music indeed!!
Those were the days, SMS777, yes?
Those were the days, SMS777, yes?
Moderator
The Queen Air didn't make noise - it made music!
If radials make music the Pratt & Whitney R-4360 Corn Con engine is an entire symphony orchestra:
It's an old article, but herewith dedicated with affection for having a common love to tail wheel.
We gotta get rid of turbines, they are ruining aviation.
We need to go back to big round engines.
Anybody can start a turbine, you just need to move a switch from "OFF" to "START," and then remember to move it back to "ON" after a while. My PC is harder to start.
Cranking a round engine requires skill, finesse and style. On some planes, the pilots are not even allowed to do it.
Turbines start by whining for a while, and then give a small lady-like poot and start whining louder.
Round engines give a satisfying rattle-rattle, click-click BANG, more rattles, another BANG, a big macho fart or two, more clicks, a lot of smoke and finally a serious low pitched roar.
We like that. It's a guy thing. When you start a round engine, your mind is engaged and you can concentrate on the flight ahead. Starting a turbine is like flicking on a ceiling fan: Useful, but hardly exciting.
Turbines don't break often enough, leading to aircrew boredom, complacency and inattention. A round engine at speed looks and sounds like it's going to blow at any minute.
This helps concentrate the mind.
Turbines don't have enough control levers to keep a pilot's attention.
There's nothing to fiddle with during the flight.
Turbines smell like a Boy Scout camp full of Coleman lanterns. Round engines smell like God intended flying machines to smell.
I think I hear the nurse coming down the hall. I gotta go.
We gotta get rid of turbines, they are ruining aviation.
We need to go back to big round engines.
Anybody can start a turbine, you just need to move a switch from "OFF" to "START," and then remember to move it back to "ON" after a while. My PC is harder to start.
Cranking a round engine requires skill, finesse and style. On some planes, the pilots are not even allowed to do it.
Turbines start by whining for a while, and then give a small lady-like poot and start whining louder.
Round engines give a satisfying rattle-rattle, click-click BANG, more rattles, another BANG, a big macho fart or two, more clicks, a lot of smoke and finally a serious low pitched roar.
We like that. It's a guy thing. When you start a round engine, your mind is engaged and you can concentrate on the flight ahead. Starting a turbine is like flicking on a ceiling fan: Useful, but hardly exciting.
Turbines don't break often enough, leading to aircrew boredom, complacency and inattention. A round engine at speed looks and sounds like it's going to blow at any minute.
This helps concentrate the mind.
Turbines don't have enough control levers to keep a pilot's attention.
There's nothing to fiddle with during the flight.
Turbines smell like a Boy Scout camp full of Coleman lanterns. Round engines smell like God intended flying machines to smell.
I think I hear the nurse coming down the hall. I gotta go.
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Moderator
What a magnificent 28 cylinder symphony of a thousand parts.
Modern aircraft rust away in a few short years; Round engine aircraft use recycled engine oil to continuously inhibit the aircraft against rust and thus last forever.
The engineer that built and maintained round engines was indeed, a master artisan that could work magic!! And with 56 spark plugs, an artisan of infinite patience.
Modern aircraft rust away in a few short years; Round engine aircraft use recycled engine oil to continuously inhibit the aircraft against rust and thus last forever.
The engineer that built and maintained round engines was indeed, a master artisan that could work magic!! And with 56 spark plugs, an artisan of infinite patience.
During my early days in aviation I flew Bristol Freighters with Air Express based in Essendon Melbourne. If my memory serves me correctly we counted the blades passing the cockpit window, primed on the fifth blade, ignition on nine blades and off she went in a cloud of white smoke, crackling and farting away. Nothing quite like it. 1980 bhp, 56 inches on take-off. Amazing engineering to time the sleeves. 30 odd gears, it looked like a giant watch in parts. 20 gallon oil tanks and each engine used around 3 gallons an hour.
Funny thing, we thundered over peoples houses rattling windows and leaking oil and nobody complained. Different times I guess.
Funny thing, we thundered over peoples houses rattling windows and leaking oil and nobody complained. Different times I guess.
During my early days in aviation I flew Bristol Freighters with Air Express based in Essendon Melbourne. If my memory serves me correctly we counted the blades passing the cockpit window, primed on the fifth blade, ignition on nine blades and off she went in a cloud of white smoke, crackling and farting away. Nothing quite like it. 1980 bhp, 56 inches on take-off. Amazing engineering to time the sleeves. 30 odd gears, it looked like a giant watch in parts. 20 gallon oil tanks and each engine used around 3 gallons an hour.
Funny thing, we thundered over peoples houses rattling windows and leaking oil and nobody complained. Different times I guess.
Funny thing, we thundered over peoples houses rattling windows and leaking oil and nobody complained. Different times I guess.
SB
Music comes from big round piston engines, not flat piston engines!
I believe this ‘engine’ is a P&W mock-up. It has 8 rows of cylinders for a total of 56!
Biggest aero engine ever built in the free world was the Lycoming XR-7755.
https://oldmachinepress.com/2018/05/...rcraft-engine/
Biggest aero engine ever built in the free world was the Lycoming XR-7755.
https://oldmachinepress.com/2018/05/...rcraft-engine/
https://oldmachinepress.com/2018/05/...rcraft-engine/
Methinks the concept of monitoring oil usage (in gal/hr) as well as fuel usage, knowing that running out of either will send you earthwards, would probably be well beyond the capabilities of most student pilots (and their EFBs) these days.
I doubt anyone would let a fledgling pilot loose on their round-engined machine without first ensuring they knew a fair bit about it, and the concept of regularly checking the oil tank(s) is hardly difficult so I'd have thought most would be capable of that.
Perhaps more challenging would be the need to understand the effect of superchargers (in some cases), and to be on your game for whenever one or more of the pots decide to let go (in some other cases), particularly as many of these machines are getting fairly long in the tooth nowadays.
And to get back to the title of the thread; most people seem to be concentrating on the external noise, internally the loudest machine I ever flew was round-engined. Magnificent though it was, it certainly made communication difficult, even with reasonable headsets - it would have been hell back in the day. Today's industrial deafness issues would have paled in comparison to these!
FP.
Moderator
Capt Fathom
Indeed it is a mock up, a prize for you for observation!
OK, I'll com clean, this is a real 4360 Wasp Major "Corn Cob" engine - 4 rows of seven cylinders = 28 cylinders:
4,362.5 cu in (71.5 L), 4,300 hp (3,200 kW) the most powerful and largest radial engine development by Pratt & Whitney.
I believe this ‘engine’ is a P&W mock-up. It has 8 rows of cylinders for a total of 56!
OK, I'll com clean, this is a real 4360 Wasp Major "Corn Cob" engine - 4 rows of seven cylinders = 28 cylinders:
4,362.5 cu in (71.5 L), 4,300 hp (3,200 kW) the most powerful and largest radial engine development by Pratt & Whitney.
The Convair B-36 had six of 'em plus four jets! No wonder they had 2 flight engineers.
Last edited by Captain Dart; 21st Mar 2023 at 04:49.