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(The Forum seems almost comatose – this is an attempt to prompt life)

 

Nostalgia - a sentimental longing or wistful affection for a period in the past or in this case an obsolete technology.

 

Have always been an admirer of the concept of doing more with less (hence my admiration of Robin Austin achievements VH -SGS & SRS)

 

Many years ago, while waxing lyrical about the performance of a Fiat 124 Sport Coupe (for those who don’t know - 1.8 L naturally aspirated, twin overhead cam, 5 speed 2 door sports sedan) – the first car I ever took to over 100 mph, cornered “on rails” and looked the part (plus “built in corrosion”). A listener butted into my verbosity with the statement - “Revs Equal Rebores” and a look of extreme contempt on his face. As you may have guessed he was a supporter of the big bore V8 (we clearly occupy different parts of the solar system).

 

The above is by way of illustration of my position – why do we persist with the big bore, slow revving, air cooled, unmuffled (very noisy), thirsty/polluting, aircraft donks that have served us so well but are now an anachronism???

 

I live under a training area for Camden, Bankstown & The Oaks. It’s also on the arrival flight path for many of the aircraft going into Sydney. I get to hear a lot of different aircraft engines – the rumble of big “jets”, the buzz of commuters, angry twins practising engine outs, the roar of aerobatic Pitts/ex “war birds”, Cessna/Pipers stalling, the occasional high-performance roar of RV /Lancair type aircraft, down to Jabs & the occasional 2/. What I rarely hear are the Rotax 912 powered aircraft – Foxebats, powered gliders and others that, are also to be seen, but little heard, overhead.

 

All too frequently I see articles in this Forum about airfield closures/operational restrictions – often arising, at least in part, from noise complaints – as a community we need to take note of what has happened in Europe, where aircraft must meet stringent noise standards.

 

You may love the sound of straight through short stack exhaust systems and wistfully compare it to the other high-profile noise polluters - Harley Davidsons and old style American derived trucks (sans working mufflers) but the rest of the world just hears noise pollution.

 

Is it not about time that we embraced the proven concepts of higher revving, turbo charging, gear reduction and mufflers to achieve the required thrust to motivate our airframes, while meeting community expectations for lower fuel/emissions and noise pollution?

I hope this has stirred the blood and there will be many passionate responses.

 

Go for it!!!

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Obtain the stroke of your favorite bores, and the rpm at cruise.

From that work out the piston speed, and the distance the piston covers in 1000 hours.

That should remove any lingering doubts.

 

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2 hours ago, turboplanner said:

Obtain the stroke of your favorite bores, and the rpm at cruise.

From that work out the piston speed, and the distance the piston covers in 1000 hours.

That should remove any lingering doubts.

 

Cause I'm thick as a short plank, I would invite you to expand - preferably with some emotive fighting words, to support whatever it is you might be trying to say.

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Well I'm not going to spend the time doing the calculation, but in simple terms a smaller engine has lower torque, but since torque x rpm - horsepower you can obtain the same horspower by revving the engine faster than the bigger engine (let's say V8 to make it simple) with the higher torque.

 

Lets give both engines the same piston/cylinder wear factor and stroke, and make the small engine spin at twice the rpm of the bug V8, and let' just look at one cylinder.

 

Twice the speed in the smaller engine = twice the stroke of the piston compared to the big V8 = twice the piston ring/bore wear.

 

At 100 km/hr I cruise my Chev 350 at 1400 rpm.

 

 

 

 

 

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I reckon the reason for airfield closures is not the noise, but the money people will pay for a housing block.

If noise is a problem, let it be tackled directly, with decibel limits. Personally, I prefer the noise of a proper engine to the whine of  rotax.  Maybe some frequencies are more annoying than others , and this could be built into the db limits.

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Love it! - more!

 

Oh! & bye the way your perfectly reasonable logic regarding wear (rev-rebores) isn't born out in the real world.

 

A well maintained 4 cylinder can easily do well above 500,000 ks - I have one that is in the 700's and never been opened. Oil consumption only slightly higher than when new and does not require toping up between changes - in most cases body/chassis/spares availability is the life limiting factor ,not the engine.

 

As for Rotax - me thinks the 2000 hr TBO, easily achieved & exceeded for most, is at least equal to the big bore air cooled jobs (many of whom will require life extending surgery well befor their TBO)

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You may speculate about the real motive for selling off airfields (& I dont disagree) but the reason so often given is the impact (noise) on quality of life of the late arriving suburbanites - why give them any ammunition?.

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2 hours ago, skippydiesel said:

Oh! & bye the way your perfectly reasonable logic regarding wear (rev-rebores) isn't born out in the real world.

 

A well maintained 4 cylinder can easily do well above 500,000 ks - I have one that is in the 700's and never been opened. Oil consumption only slightly higher than when new and does not require toping up between changes - in most cases body/chassis/spares availability is the life limiting factor ,not the engine.

 

You asked: why do we persist with the big bore, slow revving, air cooled, unmuffled (very noisy), thirsty/polluting, aircraft donks.

I gave you an answer to the big bore, slow revving part of that question.

 

Armed with that you ten switched to 4 cylinder car engines, so:

 

(a) the number of cylinders doesn't equate to piston travel

(b) it's quite normal for todays 4 cylinder car engines to make one million km, but that dosn't alter the principle I gave you.

 

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9 hours ago, skippydiesel said:

(The Forum seems almost comatose – this is an attempt to prompt life)...

 

...All too frequently I see articles in this Forum about airfield closures/operational restrictions – often arising, at least in part, from noise complaints – as a community we need to take note of what has happened in Europe, where aircraft must meet stringent noise standards.

There was a recent thread on noise but two people complained we were getting off the subject, even though we were talking about the subject. Neither of them had posted, neither have bothered to post since, so were never involved in the discussion anyway, but it killed the thread.

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For some aircraft it is not about nostalgia,  there are not any viable alternatives in the higher hp class. This 720 lyc will soon be making music with its 4 in 1 headers on each side. The prop makes the most noise. The rotax 912,914,915 are absolutely fabulous engines in their class. 

Resized_20201105_160134_403.jpg

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The thing about aircraft engines and noise is not so much the noise itself, but the stupidity of the whingers.

 

For long periods of a normal flight, the engine noise is at a constant level. The changes one hears on the ground are due to the Doppler Effect (remember approaching trains?), but I won't go into that Effect. I agree that the aerobatic types are the ones who make the most noise variation whilst dancing in the sky, but not every plane is doing aerobatics. 

 

Sensible newcomers to the vicinity of an established airport would be expected to do some investigation into the drawbacks of the location and noise is one factor. For example, if someone came to looking to buy my house in the middle of the day during the week, you'd think it was a nice quiet street. But come the peak hours, or weekends and some nights of the week, the vehicle noise can be horrendous due to cars with loud exhausts revving hard. Not to mention to clowns doing burnouts. The same goes for aircraft noise or train noise. 

 

The people who complain about noise are most often those who haven't had the sense to make these enquiries so they whinge when they realise that they haven't got the piece of paradise they thought they paid a motza for.

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There is no fly-by noise limit for aircraft in Australia; if that's what people want, microphones could be set up at the 500' climb out point on a quiet airfield and measured against an Australian Design Rule, just as it is done for cars.

Climb out is the key point for noise.

I couldn't see too many owners wanting to introduce that, but it would eliminate subjective complaints just as it does with cars.

 

There is a current issue at Parafield due to people working at home during the C-19 pandemic. In theory, when the pandemic is over and the people go back to work, the noise issue will be over.

 

However, at Parafield a local operator allows students to take off and fly in convoys of about 8, and that will also be attracting attention. They fly over other towns, also in line astern convoy, so those towns may be affected also.  

 

In cases  like this the "Amenity" of residents is reduced, and flyers need to correct the situation before it gets out of hand. This can involve modifying procedures or adding curfews, or introducing a Fly Neighbourly policy in conjunction with meetings with the local residents. If the airfield doesn't take action or if talks break down the residents can take the matter to a State Tribunal for Review, in this case The South Australian Covil and ADministrative Tribunal (SACAT). That's not a place you want to be in because Amenity is a Planning matter and what the Member decides goes.

 

 

 

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The Air Navigation (Aircraft Noise) Regulations 2018 only apply to:

subsonic jet aircraft means an aircraft that:

                     (a)  is propelled by one or more engines of the following kinds:

                              (i)  turbofan engines;

                             (ii)  turbojet engines;

                            (iii)  unducted fan engines;

                            (iv)  rocket engines; and

                     (b)  is not capable of sustained level flight at a speed equal to or greater than the speed of sound.

supersonic aircraft means an aircraft that is capable of sustained level flight at a speed equal to, or greater than, the speed of sound.

 

There does not seem to be anything else in those regulations applying to aircraft with an MTOW less than 5700 kg.

 

The Airports (Environment Protection) Regulations 1997 do not apply to:

                     (a)  pollution generated by an aircraft; or

                     (b)  noise generated by an aircraft in flight or when landing, taking off or taxiing at an airport.

 

So basically, there are now laws governing how much noise an aircraft with a MTOW of less than 5700 kg can make.

 

No Law - No Offence.

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7 hours ago, turboplanner said:

You asked: why do we persist with the big bore, slow revving, air cooled, unmuffled (very noisy), thirsty/polluting, aircraft donks.

I gave you an answer to the big bore, slow revving part of that question.

 

Armed with that you ten switched to 4 cylinder car engines, so:

 

(a) the number of cylinders doesn't equate to piston travel

(b) it's quite normal for todays 4 cylinder car engines to make one million km, but that dosn't alter the principle I gave you.

 

The origination quote (Revs = Rebores) was about car engines, as an illustration, I merely continued in that vain but then went on to show that small capacity high revving aircraft engines can also meet (& exceed) the generally accepted/applied market standard of 2000 TBO.

 

I would not dispute your logic, only how it applies to the real world ie so your slow revving big bore could (in theory) out last a small capacity high revving engine but in reality other factors seem to come into play, impacting on the potential that the theory alludes too.

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13 minutes ago, old man emu said:

So basically, there are now laws governing how much noise an aircraft with a MTOW of less than 5700 kg can make.

No Law - No Offence.

There are no specification limits on an aircraft, but there is Amenity, which is a part of Planning Law to protect the community, which I just pointed out in the thread above.

 

An airfield which has been operating the same way with the same types of aircraft for a certain amount of time gains Existing Use Rights. If people move into the area to live, and then start trying to re-engineer the zone, Civil Administrative Tribunals are not going to be sympathetic to them.

 

Where someone starts doing something different in an established area and reduces the Amenity of the residents, CATs are not going to be sympathetic to the airfield.

 

Because Amenity cases are usually fought out between two parties the results can be all over the place.

 

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7 minutes ago, skippydiesel said:

The origination quote (Revs = Rebores) was about car engines, as an illustration, I merely continued in that vain but then went on to show that small capacity high revving aircraft engines can also meet (& exceed) the generally accepted/applied market standard of 2000 TBO.

 

I would not dispute your logic, only how it applies to the real world ie so your slow revving big bore could (in theory) out last a small capacity high revving engine but in reality other factors seem to come into play, impacting on the potential that the theory alludes too.

The basic principle applies to the real world, but is just the base of the design.

If you want a B Double to haul 68 tonnes for 250,000 km/year with an in-frame rebuild of 1.5 million km, you'll be settling for a big capacity, slow revving high torque engine.

If you want to build a Formula 1 engine, all it has to do is fall over the line at the end of the race, but it must be light, so it can be a small capacity very low torque engine with very high revs (Torque x rpm =hp).

Within those two extremes you can also do hundreds of other things to get the perfect engine for your application.

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3 hours ago, Thruster88 said:

For some aircraft it is not about nostalgia,  there are not any viable alternatives in the higher hp class. This 720 lyc will soon be making music with its 4 in 1 headers on each side. The prop makes the most noise. The rotax 912,914,915 are absolutely fabulous engines in their class. 

Resized_20201105_160134_403.jpg

Great looking engine - certainly "presses my buttons" .

 

The thing is, liquid cooled, high revving (geared) high horsepower,  aircraft engines have been around for ever (I am fairly sure Continental had at least one).

 

Nev will know for sure but the now accepted horizontally apposed air cooled donk has only been around since WW2. Unlike the automotive world little pressure & relativly small market have combined (with liability concerns) to make innovation in this area glacial.

 

Rotax did not invent this wheel, however their popularity (despite high acquisition cost) proven ability to make an acceptable TBO, lower fuel consumption/reduce pollution, quite running continue to demonstrate what could be, in the rest of the market.

 

In my simple mind it is the overwhelming influence of the USA market that is holding up development in this area. Your average "Septic Tank" seems to be besotted with the big bore (made in the USA) engine to the exclusion of all else.

 

The Europeans on the other hand have, at least since WW2, been focused on fuel efficiency (in their land and air vehicles) and this seems to have driven their development efforts. In more recent times noise & air pollution have also been high on the agenda.

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2 hours ago, turboplanner said:

There are no specification limits on an aircraft, but there is Amenity, which is a part of Planning Law to protect the community, which I just pointed out in the thread above.

I agree with that. The reason I posted the law stuff was simply to point out there are no rules at present for limits on aircraft noise. So if Joe Citizen wants to complain about the passage of aircraft over his house, he would have to look elsewhere for a legal precedent. 

 

It amazes me how many homes back onto railway tracks or freeways and the only thing that those locations do is lower the price of houses and land compared to similar houses and land located in the same suburb, but away for the transport infrastructure. People will still trade off noise for reduced price. Besides I've seen places right beside railway lines that have solved the problem with double glazing. 

https://www.lifestyle.com.au/property/selling-houses-australia-series-5-railway-cottage.aspx

 

Double glazing doesn't seem to be common in residential housing in Australia.

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1 minute ago, skippydiesel said:

Come on guys - help me out I am just trying to get a bit of lively/life signs - someone defend those obsolete air cooled monstrosities

I will, just need the $5 billion first though before i lift a finger anywhere near a drawing board.

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2 hours ago, skippydiesel said:

Come on guys - help me out I am just trying to get a bit of lively/life signs - someone defend those obsolete air cooled monstrosities

I have two lycoming powered aircraft, they don't need defending.  

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31 minutes ago, Thruster88 said:

I have two lycoming powered aircraft, they don't need defending.  

Two! Obviosly a need for redundancy

 

Go on  - give it a go. Whats are they (model, hp) & why are they so great??

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One of these guys travels in a bullet proof train, as he can't find spare parts for his elderly aircraft. His buddy is in denial, and has a loose wheel connecting his hairpiece to his neck. I sometimes miss my Cadillac Eldorado, but a Lycoming 720 would be even awesomer if properly attached to a fast airframe.

Screenshot_20201116-201750.png

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Shortfielder - I am also deeply effected by nostalgia - I used to have a "thing" for Mercedes W123 (1977-85) 300D & 240D's - had 7 of them at one time - something had to "give" at retirements & it was the Merc's. I could go on about the old diesel Merc's for pages but will control myself and just say - many achieved over 1 million K's, accelerated like "watching paint dry " but could maintain 160 ks all day (if so required), cornered "on rails" and just soaked up the corrugations/bumps. My best one achieved any easy 7L/100K  (this is for a near 2 tonne car). Technology way ahead of the "herd" super easy to work on/maintain and parts cheap & plentiful 

 

BUT

 

Not a patch on my Ford Ranger, great car, which wont last as long, but does things (like pull heavy trailers) that the Mercs should never be asked to do. .

 

My point is, when do you say we have stuck with the lovely old engines long enough and need to move forward, not for the sake of change but to incorporate/take on a load of improved technologies/concepts??

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