What would early 1900s aeroplanes sound like if they were powered by electric engines ?

[Petike]

"Well, they'd probably be more quiet, Petike." some of you might say.

More seriously, I've been wondering about this question for an aeronautic-themed story I've been writing.

Its setting is a largelly realistic alternate world with pre-WWI and early WWI style aviation.

For the sake of argument, let's pretend we're in the early days of aviation in an OTL early 1900s sort of context. Electric engines and the electric batteries powering them are lightweight enough and powerful enough to lift an early monoplane, biplane or triplane. The batteries in particular are lightweight and can last a fair few hours after charging. (I imagine these as comparable to batteries used by early electric cars like the Baker or the Detroit, just more powerful for the needs of a plane.)

This is somewhat of a tricky topic, and given some of the necessary tech, it might border on ASB with the technology we had in OTL 1900s. So, aside from the "magic" batteries, powerful and lightweight enough, let's say the electric engines are otherwise very similar to those we had in our world between 1895 and 1920.

You own a Blériot XI, or a Demoiselle, or any other simple, common one-seater or two-seater plane, comparable to those of our world's pre-WWI era. You take the original liquid fuel-powered engine and fuel tanks out of the engine compartment, and you then install an electric engine and balanced battery racks instead. How will the setup roughly look like ?

Finally, the main question of this thread: You get your aeroplane flying, you take off, fly (maybe the acceleration or top speed is weaker, who knows) and you hear the sound of your engine. (I am interested in this question for narrative reasons, and potentially sound effect reasons as well.)

What would the electric engine of such an aeroplane sound like ?

Would it be a quieter engine, or not by much compared to a petrol engine of the era ?

And does electric propulsion make rotary engines unnecessary ?

 

[AJE]

Assuming they invent a battery light enough to do this (no battery even today is anywhere near light enough to be practical for this), it would depend on the motor type. If it's just a a simple motor taking current straight from the battery and directly powering a propeller, noise from the bearings and the cooling fan (which will be needed) would be the only source of engine noise, and that wouldn't be much. This would mean the main noise would come from airflow and in particular the propeller- there have been some quiet turboprops and piston engines, and the main source of noise is the propeller blades. Otherwise though, it would probably sound a lot like a glider. With our modern solid-state alternators and quietened motors, modern electric aircraft probably sound a lot like this too, so you could look up videos of electric aircraft prototypes to see how they sound (most of the noise probably comes from the propellers or airflow).

It may be that the electric motor is large and heavy enough (they certainly were back then) that using a simple motor taking current straight from the battery and directly powering a propeller is too heavy. To make it smaller, the motor might be an induction motor using alternating current with an inverter converting the battery direct current to alternating current (unlikely though, as the inverter would probably have to be rotary back then and be just as heavy as a simple motor by itself). This might make a humming noise as most heavy AC equipment does because of the oscillations.

The other option would be to make the motor run faster, and be connected to the propeller by a gear. This would make the motor much smaller, but at very high speeds, like the Alexanderson alternator (ran at jet engine speeds- 20,000 RPM), the noise is noticeable on large machinery:

This probably would be noticeable on very large aircraft, if they and batteries to power them existed.

 

[Tessitore]

Weirdly this reminds me of an aviation AU idea of my own that I was contemplating that had a couple of PODs, one of them being the invention of either a superior battery or an early fuel cell by a British educated Anglo-Indian genius who didn't exist in OTL. I never figured out the technical specifics though.

 

[marathag]

This is somewhat of a tricky topic, and given some of the necessary tech, it might border on ASB with the technology we had in OTL 1900s. So, aside from the "magic" batteries, powerful and lightweight enough, let's say the electric engines are otherwise very similar to those we had in our world between 1895 and 1920.

General Aviation can run into the prop tips running supersonic, and that drowns out the engine noise
https://aopalive.aopa.org/detail/vi...ic-propeller-tips---the-sound-of-inefficiency

 

[Aghasverov]

A hybrid aircraft could be interesting... using an IC engine for takeoff and climb, or when a burst of speed is required, but switching to the electric drive for cruising... could have implications for high-altitude flight, as an electric motor wouldn't have the same problems with carburetion due to low air density...

 

[Aghasverov]

General Aviation can run into the prop tips running supersonic, and that drowns out the engine noise
https://aopalive.aopa.org/detail/vi...ic-propeller-tips---the-sound-of-inefficiency

I've read that some of the big Kutznetsov turboprops are insanely loud because of this....

 

[Petike]

Assuming they invent a battery light enough to do this (no battery even today is anywhere near light enough to be practical for this), it would depend on the motor type. If it's just a a simple motor taking current straight from the battery and directly powering a propeller, noise from the bearings and the cooling fan (which will be needed) would be the only source of engine noise, and that wouldn't be much. This would mean the main noise would come from airflow and in particular the propeller- there have been some quiet turboprops and piston engines, and the main source of noise is the propeller blades. Otherwise though, it would probably sound a lot like a glider. With our modern solid-state alternators and quietened motors, modern electric aircraft probably sound a lot like this too, so you could look up videos of electric aircraft prototypes to see how they sound (most of the noise probably comes from the propellers or airflow).

It may be that the electric motor is large and heavy enough (they certainly were back then) that using a simple motor taking current straight from the battery and directly powering a propeller is too heavy. To make it smaller, the motor might be an induction motor using alternating current with an inverter converting the battery direct current to alternating current (unlikely though, as the inverter would probably have to be rotary back then and be just as heavy as a simple motor by itself). This might make a humming noise as most heavy AC equipment does because of the oscillations.

The other option would be to make the motor run faster, and be connected to the propeller by a gear. This would make the motor much smaller, but at very high speeds, like the Alexanderson alternator (ran at jet engine speeds- 20,000 RPM), the noise is noticeable on large machinery:

This probably would be noticeable on very large aircraft, if they and batteries to power them existed.

This is a really fantastic post !

Even after all these years here on AH.com, I've rarely received a first reply in one of my threads that would be this straightforwardly and exhaustively informative. Pat yourself on the back, your post has been very informative and it's cleared up a lot of uncertain aspects for me.

Weirdly this reminds me of an aviation AU idea of my own that I was contemplating that had a couple of PODs, one of them being the invention of either a superior battery or an early fuel cell by a British educated Anglo-Indian genius who didn't exist in OTL. I never figured out the technical specifics though.

Two of the biggest issues with using OTL early 1900s electric engines for aviation are weight (batteries in particular were quite hefty) and performance. In the latter case, some experiments with electric engines even before 1920 yielded some promising results, but the engines had a tendency to get severely worn down in use, and be essentially inoperable after a few test flights. Late Austro-Hungarian engineers experimenting with an electric spotter-helicopter found this out fairly soon.

The late 1800s saw the first electric airship among several airship pioneers in France, something that sounds straight out of a Jules Verne novel (and was probably even read about by him, given that he was still around, in his older years).

I really like that you wanted to develop such an AU idea. My own setting and narrative aren't really conventional AH, though it has AH trappings and was inspired by early science fiction (especially the faith of many early 1900s people in electrically powered vehicles) and early aviation fiction. The technology of the setting is, while occassionally a tiny bit more fanciful, heavily grounded in reality. I wanted it to be a sort of dieselpunk-but-with-electric-engines Edwardian era type world.

A hybrid aircraft could be interesting... using an IC engine for takeoff and climb, or when a burst of speed is required, but switching to the electric drive for cruising... could have implications for high-altitude flight, as an electric motor wouldn't have the same problems with carburetion due to low air density...

Interesting idea. Though with a clear disadvantage, even when compared with a hybrid passenger car.

You'd need to carry two engines aboard your hybrid aircraft, and while in cruising flight, the IC engine would be more or less dead weight.

General Aviation can run into the prop tips running supersonic, and that drowns out the engine noise
https://aopalive.aopa.org/detail/vi...ic-propeller-tips---the-sound-of-inefficiency

I've read that some of the big Kutznetsov turboprops are insanely loud because of this....

Yes, indeed.

 

[AJE]

This is a really fantastic post !

Even after all these years here on AH.com, I've rarely received a first reply in one of my threads that would be this straightforwardly and exhaustively informative. Pat yourself on the back, your post has been very informative and it's cleared up a lot of uncertain aspects for me.

I'm flattered you like the post, but that wasn't really up to my usual standards for detailed posts. That was just to get my thoughts out quickly with the time I had, and I'll have to put the rest in this post.

The overall appearance of the setup depends partly on the motor size and shape, but fortunately by the early 1900s electric motors had settled into a mature and consistent form:
Professor Eric Laithwaite: Shaping Things to Come- 1972

It seems that Charles Proteus Steinmetz was one of the last major contributors to this, his developments allowing motors to be more systematically analyzed and optimized into their modern forms. Once that form was attained, they were probably lighter than equivalent piston engines (older ones were much heavier as the video shows, but the same goes for older piston engines). They are heavier than equivalent jet engines but that's not a factor in this timeframe. Their shape appears to be close to a radial engine and more compact, so the motors would probably be mounted like rotary or radial engines. The motors might be small enough that propellers and motors are placed in nacelles like ship azimuth thrusters.

For the batteries, it depends on whether the batteries are dry or wet cell (wet cell probably isn't as rigid), and whether they can be used as structure. Given aircraft of the time are mainly wood and canvas, they probably couldn't easily be used as structure so they would be contained in the fuselage. There will need to be some electronics to transfer power from the batteries to the motor. These may as well be placed near the batteries or the motors, whichever one requires bulkier lines. (For example, if the electronics-motor connection weighs more per meter than the battery-electronics connection, then as much of the connection as possible should be battery-electronics. Then the electronics would be placed next to the motor.)

General Aviation can run into the prop tips running supersonic, and that drowns out the engine noise
https://aopalive.aopa.org/detail/vi...ic-propeller-tips---the-sound-of-inefficiency

The propeller speed depends on what time period it is. In the early days- at least after the Wright Brothers invented the modern propeller- wooden propellers ran at low speeds for efficiency. In 1921 Dr. Sylvanus Albertus Reed showed that the disappearance of thrust at high tip speeds could be overcome and invented a new aluminium propeller which could run at the higher speeds of new engines:

In 1915, while engaged in research on high-frequency acoustics, Dr. Reed was employing an apparatus with a shaft revolving at 36,000 rpm. It occurred to him that it would be interesting to conduct similar experiments with high-speed propellers. He was fully cognizant of the problems that were believed to arise when any object moving through air approached the speed of sound, a belief based on the experience from tests conducted with artillery shells. It was known that at or near the speed of sound there is a critical point on the curve of the relation to air resistance, but Reed professed a truly scientific attitude of mind by not believing anything before it had been proven- all the more as he had been told that the subject of very high propeller tip speeds was a field that had not been explored.

Reed thought that the difficulties encountered when the speed of sound was reached might well be dependent upon the shape of the moving object. He then proceeded to conduct a long series of experiments, first with propellers 20 inches long which he revolved at 14,000 rpm- ascertaining, perhaps a bit rashly, that the supposed physical limit at the speed of sound did not exist and that the thrust of his propellers did not undergo any appreciable variation when exceeding that limit.

This was truly a revolutionary theory at that time, considering that as late as 1919 the British Advisory Committee for Aeronautics had issued an official report of its own experiments in which it was affirmed that thrust practically disappeared at high tip speeds, a conclusion corroborated by American tests conducted at McCook Field. Nevertheless, Reed was able to interest officials of the Curtiss Company in his research, especially William Gilmore, chief airplane engineer in charge of airframe design, who placed full facilities for further testing at Reed's disposal.

The final result of Reed's experiments was the Z-1 propeller of 1921, which had very thin tips and razor-sharp edges. In fact, Reed had anticipated what the aeronautical engineers would discover 25 years later when the speed of sound would be approached by full-size aerofoils. To be able to obtain the necessary thin section, the Reed propeller was made of aluminum in one forging. It gave excellent results, being capable of very high efficiency at hitherto unheard-of speeds of rotation. It became the perfect associate for the direct-drive D-12 engine, which seemed eager to turn at speeds higher than the 2,000 rpm to which it had been restricted by the older types of airscrew.

Source (Page 60), other versions of file are found here

In the mid-late 1920's reduction gears were finally made reliable (most likely due to research described on pages 20-21 of this article, the full article is found here). This made propeller tip speeds go down again, as propellers are more efficient at slower speeds and now engine speed (and power) could be increased without making the propeller tips run faster. Instead thrust was increased by adding more blades:

The ultimate development of this are probably the propfan prototypes developed in the 1980's, though they and most modern airliner-speed propellers have high noise levels due to the high speed required.

 

[Petike]

I'm flattered you like the post, but that wasn't really up to my usual standards for detailed posts. That was just to get my thoughts out quickly with the time I had, and I'll have to put the rest in this post.

Hello, sorry I didn't reply sooner. So here's my reply.

Regardless of whether it was a quick sketch or not, it was one of the most useful and informative reply posts I've ever received in any of my threads, in all my years on AH.com. Thanks again, for the previous post and this one !

The overall appearance of the setup depends partly on the motor size and shape, but fortunately by the early 1900s electric motors had settled into a mature and consistent form:
Professor Eric Laithwaite: Shaping Things to Come- 1972

Laithwaite had some excellent lectures ! They don't even feel dated, despite the half a century gap !

It's funny to think maglev trains were seen as the hot new and unexplored technology back in the day...

I liked the explanation on the trial-and-error process of developing electric engines. Seems it was very much similar to planes and other technology: Highly exotic and almost bizarre design-wise (from our contemporary perspective), until it settled into something of a proven design that you only need to iterate and update for the sake of improvements, but not entirely revise.

It seems that Charles Proteus Steinmetz was one of the last major contributors to this, his developments allowing motors to be more systematically analyzed and optimized into their modern forms. Once that form was attained, they were probably lighter than equivalent piston engines (older ones were much heavier as the video shows, but the same goes for older piston engines). They are heavier than equivalent jet engines but that's not a factor in this timeframe. Their shape appears to be close to a radial engine and more compact, so the motors would probably be mounted like rotary or radial engines. The motors might be small enough that propellers and motors are placed in nacelles like ship azimuth thrusters.

This is one of the most fascinating aspects of the whole thing !

In all honesty, I feel that nacelle-engines in the vein of azimuth thrusters would be less suitable to conventional heavier-than-air aeroplanes, and perhaps even more useful in electrically-powered airships. I have just thought of the engine nacelles of such an airship being able to swivel horizontally when needed, in the vein of azimuth thrusters (though built in a way where they'd be in a traditional fixed position unless set otherwise by the crew/steersmen through some onboard control system).

For the batteries, it depends on whether the batteries are dry or wet cell (wet cell probably isn't as rigid), and whether they can be used as structure. Given aircraft of the time are mainly wood and canvas, they probably couldn't easily be used as structure so they would be contained in the fuselage. There will need to be some electronics to transfer power from the batteries to the motor. These may as well be placed near the batteries or the motors, whichever one requires bulkier lines. (For example, if the electronics-motor connection weighs more per meter than the battery-electronics connection, then as much of the connection as possible should be battery-electronics. Then the electronics would be placed next to the motor.)

This seems easy enough to get right. The vast majority of the planes I'm talking about are single-propeller machines, so there's no need for several engines, and the engine compartments are as small as on any petrol engine early 1900s (pre-WWI style) aircraft.

The propeller speed depends on what time period it is. In the early days- at least after the Wright Brothers invented the modern propeller- wooden propellers ran at low speeds for efficiency. In 1921 Dr. Sylvanus Albertus Reed showed that the disappearance of thrust at high tip speeds could be overcome and invented a new aluminium propeller which could run at the higher speeds of new engines:

Source (Page 60), other versions of file are found here

Yeah, I know about the propeller tips speed issues, concerning thrust. A bit of a similar issue as planes before the 1950s hitting their acceleration limits due to wing shape and wings angled backward needing to be implemented with the rise of the jet age.

In the mid-late 1920's reduction gears were finally made reliable (most likely due to research described on pages 20-21 of this article, the full article is found here). This made propeller tip speeds go down again, as propellers are more efficient at slower speeds and now engine speed (and power) could be increased without making the propeller tips run faster. Instead thrust was increased by adding more blades:

That's great, but also a bit moot, as my question is focused on pre-1920s aeroplanes. Unless the research or materials science greatly catch on much earlier (in OTL or my fictional early 1900s setting), I can't see these advances occuring in the canvass-and-wood era of planes (which was already firmly on its way out by the 1920s, especially by the late 1920s).

I think my setting is not yet capable of propeller advances like this. The vast majority of propellers are still manufactured from wood, and there might be an issue with how thin and even you can make such a wooden propeller. Three-bladed to four-bladed propellers might be the answer when it comes to improving thrust, but I worry that there might be weight issues, given the material used. Most of my setting's planes are still too archaic and too slow overall to bother with focusing too much on thrust issues, as useful as it would be once such concerns start becoming more necessary and prevalent, with the ongoing development of aviation in that setting.

The ultimate development of this are probably the propfan prototypes developed in the 1980's, though they and most modern airliner-speed propellers have high noise levels due to the high speed required.

Yeah, I know. The setting I am researching this topic for more in-depth doesn't even have 1920s+ developments, nevermind developments that came many decades later in OTL. So propfan prototypes of recent decades are out of the question. Like with the aforementioned stuff, I fear that the materials science of the setting just isn't there yet to manufacture innovations like these. At least not in any economical manner.

 

[e of pi]

The answer I suspect is "still pretty noisy":

Harbour Air to resume electric-powered Beaver flights as certification work begins

Canadian commuter airline Harbour Air expects to conduct additional flight tests of its electric-powered de Havilland Canada DHC-2 Beaver as soon as next week as it builds off a successful first flight last month.

www.flightglobal.com

Lower power electric aircraft basically sound like a power drill , especially the really small props.

 

[Petike]

The answer I suspect is "still pretty noisy":

Harbour Air to resume electric-powered Beaver flights as certification work begins

Canadian commuter airline Harbour Air expects to conduct additional flight tests of its electric-powered de Havilland Canada DHC-2 Beaver as soon as next week as it builds off a successful first flight last month.

www.flightglobal.com

Lower power electric aircraft basically sound like a power drill , especially the really small props.

Teehee.

Well, I suspected that there would be some whirring while they'd be in flight. I think you could dampen the overall noise a bit with a shroud around the engine. After all, you don't want weather conditions to play havoc with the engine and batteries, so some sort of cover at the top and sides would be useful. Put some light but thick padding on the inside of the shroud, and the sounds should go down considerably.

If you're flying open to the elements, without a canopy for the pilot, then you'll be hearing the whooshing of the air and wind around you anyway, and the noise of the engine will hardly be as loud as one would expect.

 

[e of pi]

Teehee.

Well, I suspected that there would be some whirring while they'd be in flight. I think you could dampen the overall noise a bit with a shroud around the engine. After all, you don't want weather conditions to play havoc with the engine and batteries, so some sort of cover at the top and sides would be useful. Put some light but thick padding on the inside of the shroud, and the sounds should go down considerably.

Definitely a ducted fan could be made quieter than an open propeller, with the addition of a lot of acoustic deadening. I doubt, however, that the extra weight would be worth it--the motor itself would be at the center of the shaft (and behind the reduction gearbox) and the batteries even deeper within the fuselage. Moving a lot of air is just pretty noisy, even if the power source for it isn't. If you look up electric RC ducted fans, they're also pretty noisy.

With a much lower power motor and a relatively large prop, it might be quieter, like this, but you'll note it's still not exactly silent.

 

[Driftless]

With the first generation H-t-A pioneers, wouldn't there also be a fair bit of humming from the yards of structural wires and struts?

 

[marathag]

The answer I suspect is "still pretty noisy":

Harbour Air to resume electric-powered Beaver flights as certification work begins

Canadian commuter airline Harbour Air expects to conduct additional flight tests of its electric-powered de Havilland Canada DHC-2 Beaver as soon as next week as it builds off a successful first flight last month.

www.flightglobal.com

Lower power electric aircraft basically sound like a power drill , especially the really small props.

That's with modern glass or kevlar fiber reinforced polymer gears.
Metal gears, pre WWI would be straight cut, and noisy

jump to 6 minutes in or so.
note gear noise exceeds exhaust note.
Noise =wasted power
later cars had helical/hypoid cut on the teeth, better mesh and power transfer capability than straight cut

 

[AJE]

The answer I suspect is "still pretty noisy":

Harbour Air to resume electric-powered Beaver flights as certification work begins

Canadian commuter airline Harbour Air expects to conduct additional flight tests of its electric-powered de Havilland Canada DHC-2 Beaver as soon as next week as it builds off a successful first flight last month.

www.flightglobal.com

Lower power electric aircraft basically sound like a power drill , especially the really small props.

But the noise does not require headphones so a conversation can be held normally, and the main source of noise is only the airflow and not the engine. Depending on the design electric aircraft tend to be anywhere from 1/2 to 1/10 as noisy as gas-powered ones:

Kitty Hawk's new electric aircraft is quieter than a dishwasher​

Electric planes: a quiet revolution in the Swiss skies​

Electric planes: the revolution has some snags​

Impact of electric propulsion on aircraft noise – all-electric light aircrafts case study​

That's with modern glass or kevlar fiber reinforced polymer gears.
Metal gears, pre WWI would be straight cut, and noisy

jump to 6 minutes in or so.
note gear noise exceeds exhaust note.
Noise =wasted power
later cars had helical/hypoid cut on the teeth, better mesh and power transfer capability than straight cut

The gears were over 98% efficient even in 1897 (Source- page 112), and most aircraft piston engines settled on straight cut reduction gears after the failures of herringbone reduction gears (the Curtiss K-12 being probably the last of them).

 

[NHBL]

A hybrid aircraft could be interesting... using an IC engine for takeoff and climb, or when a burst of speed is required, but switching to the electric drive for cruising... could have implications for high-altitude flight, as an electric motor wouldn't have the same problems with carburetion due to low air density...

nteresting idea. Though with a clear disadvantage, even when compared with a hybrid passenger car.

You'd need to carry two engines aboard your hybrid aircraft, and while in cruising flight, the IC engine would be more or less dead weight.

One solution to the extra weight needed for take off would be RATO units. (Rocket Assisted Take Off.) Nice solid rocket boosters shove the plane aloft, then are dropped--hopefully not on someone's head. (One of the timelines I'm working on has got me looking at EARLY rockets...)

 

[Petike]

Ladies and gentlemen, here are three early aeroplanes I want to use as examples...

Do you think we can get these airborne with pre-1920s tech ? Even if the chemicals in the batteries will have to be somewhat ASB in terms of life and propulsion performance, as I've mentioned earlier in this discussion ? (For the sake of argument, let's accept the batteries issue has been cracked and they're up to snuff, even if it is a tiny bit ASB.)

 

[Petike]

Definitely a ducted fan could be made quieter than an open propeller, with the addition of a lot of acoustic deadening. I doubt, however, that the extra weight would be worth it--the motor itself would be at the center of the shaft (and behind the reduction gearbox) and the batteries even deeper within the fuselage. Moving a lot of air is just pretty noisy, even if the power source for it isn't. If you look up electric RC ducted fans, they're also pretty noisy.

I think you misunderstand what I'm getting at.

Even though you could make a ducted fan design with Edwardian era technology, it's entirely unnecessary. It would be just a lot of extra weight for little gain, as you yourself have said. I was talking purely about the engine compartment having some sort of a simple cover that would reduce engine noise. Though, already, the noise would be noticeably lower than that of a petrol-powered Edwardian era or WWI era petrol-powered aeroplane.

With a much lower power motor and a relatively large prop, it might be quieter, like this, but you'll note it's still not exactly silent.

Well, the goal was never to create a near-silent plane, the question was more about whether it would be more silent, or equally loud as a petrol-powered plane. How loud would it be, how different it would probably sound, compared to a petrol-powered aeroplane of the same era...

With the first generation H-t-A pioneers, wouldn't there also be a fair bit of humming from the yards of structural wires and struts?

Depends on whether there was, and in the case of replicas is, humming on petrol-powered canvass aeroplanes.

To have humming, you need vibrations. Would an electrically powered aeroplane vibrate on its surface as much as a petrol-powered plane ?

That's with modern glass or kevlar fiber reinforced polymer gears.
Metal gears, pre WWI would be straight cut, and noisy
jump to 6 minutes in or so.
note gear noise exceeds exhaust note.
Noise =wasted power
later cars had helical/hypoid cut on the teeth, better mesh and power transfer capability than straight cut

No offence, but this completely ignores the fact that we're not talking about petrol-powered cars and petrol-powered planes, but electrically powered cars and planes. I think you should compare the level of noise to that of a Baker Electric or Detroit Electric. Those 1900s-1910s electric cars, while not exactly fast and tough, were fairly quiet, while still being audible. They had a very simple electric engine, and even if their moving parts were louder, it was hardly ear-splitting.

An electric plane of the era will be louder, but compared to the noise of something like a Fokker F.VIII, an electrically powered aeroplane is going to be humming and whirring audibly and clearly, but nowhere near that same volume of decibels. Not even close.

Just listen to this one. It's like someone crossed an East Block cheap motorbike with a rabid lawnmover, heh.

Petrol engines need more moving parts, both in cars and in planes, and in all other motorised vehicles. That's a simple fact. If you're going to use a liquid fuel combustion engine, you need more moving parts in an engine, more gears, more mechanical complexity, in order for the engine to work at all. Internal combustion, with its very carefully managed mini-explosions serving as motive power, require that, whether we like it or not.

It's telling that both historical and contemporary electrical cars have, as far as I know, never needed transmission. Or only token versions of it, similar to a watered-down automatic transmission or transmissions on an ordinary mountain bike. Whereas in a petrol car in particular, you have to shift gears at certain speeds, and you have no choice in the matter, in an electric one, you don't bother with gear shifting at all.

But the noise does not require headphones so a conversation can be held normally, and the main source of noise is only the airflow and not the engine. Depending on the design electric aircraft tend to be anywhere from 1/2 to 1/10 as noisy as gas-powered ones:

I concur. Very well summed up.

The question isn't whether they can be noiseless (they're planes, I doubt that), but how loud they would be if entirely electrically powered.

Thank you for the links.

The gears were over 98% efficient even in 1897 (Source- page 112), and most aircraft piston engines settled on straight cut reduction gears after the failures of herringbone reduction gears (the Curtiss K-12 being probably the last of them).

Yes, the early 20th century wasn't the 1800s anymore, they figured out that crudely manufactured parts are not conductive to performance.

If these parts were so catastrophically inefficient for decades, I think a lot of vehicle manufacturers would have long gone out of business.

One solution to the extra weight needed for take off would be RATO units. (Rocket Assisted Take Off.) Nice solid rocket boosters shove the plane aloft, then are dropped--hopefully not on someone's head. (One of the timelines I'm working on has got me looking at EARLY rockets...)

I'm sorry, but this has already been discussed, and it's also a topic that isn't the focus of this thread. I didn't ask "Would electric planes only be viable if you haphazardly strapped rocket boosters to them on takeoff ?". That's a whole other topic I'm afraid, even if it is an interesting topic.

The more complicated solutions you add to an early plane, the worse the potential solving of tech problem gets. Why complicate things even further by trying to figure out rocket-powered aircraft - an area of research where knowledge was lacking until the 1920s and 1930s - if your primary concern was figuring out whether you can get a plane flying with an electric engine ?

 

[marathag]

but electrically powered cars and planes. I think you should compare the level of noise to that of a Baker Electric or Detroit Electric.

Early ICE aero engines ran without reduction gears, as they were low RPM, and had enough useful torque to spin the prop.
Electric motors tend run at higher RPMs, and high RPMs get you into that supersonic tip speed.
Bakers used chain drive for their reduction, and only 3.5HP, with 6 HP overload for around 10 minutes at 150 amps
You won't be getting off the ground with that low of HP, unless you have zero weight batteries

 

[James Ricker]

A soft buzzing from the electric engine but propellers were not that efficient in the 1900s so there would be the characteristic chop chop sound of the propeller inefficiently moving through the air