light aircraft engines

[lightonthewater]

As a non-pilot, I read so much in these pages about engine failures, accidents and near-accidents in light aircraft due to such things as carburettor icing, lean or rich mixture, plug fouling, poor power output etc. All of these were also common in car engines in the 1960's or 70's but are almost unheard of in modern cars, which are very reliable, and mostly have fuel injection and often turbos as standard, as well as plenty of automatic control over adjustments for temperature and air density. Given the negative consequences of engine failure in the air are far greater than in a car, why is it that so many relatively modern light aircraft apparently have such antiquated power plants, and require so much manual adjustment and control? Obviously, historic aircraft are a different matter, but updated engines with modern automation etc would reduce the pilots workload and improve reliability and safety enormously. (forgive my ignorance)

[Pilot DAR]

The prevailing design requirements for certification are "old", by today's standards, but based upon simple wisdom. A lot of this wisdom has been born of experience, a lot of it from WW2 airplanes. Within these requirements, an engine for a certified aircraft, must itself be certified. That process is very expensive and burdensome. And, referring to the [present] engine certification design requirements, certain simplicities are required. One of those is that the engine must be able to run without an external source of electricity - hence magnetos. Nearly all legacy horizontally opposed piston engines are direct drive, which is simple and reliable, but contrary to modern engine design. Certainly some modern engine installations are being certified with variations on these requirements (by "special conditions"), but it's expensive. So, for a brand new airplane design, with a modern engine, it may be worth the investment. But, for an airplane designed in the 1960's, and built '60's to '80's, it may not be worth a million dollar program to certify a more modern engine, when you can just keep rebuilding the original one.

Present light airplane engines (Continental and Lycoming) are surprisingly simple, and lightweight for the power that they produce. They are comparatively reliable, when I consider the "computer" problems I have experienced with modern car engines! Many of the failures you may read about are a result of improper operation, rather than the engine itself failing mechanically. But yes, they are old and very basic in design. To get modern engines into the general aviation fleet, will require lots of money, and regulatory advancement (= money + time). The general aviation industry is not known for having excess money!

[Jan Olieslagers]

Some of the most common light planes are quite old designs, and use engines of corresponding age. Especially those from the US: C150/152, C172, PA28, Beech Bonanza, ...

From Europe comes the Rotax family, which still uses carburettors but has no need for carb heat nor for mixture control. And they now have an injected version too, though I do not see it achieving great commercial success.

The only engines for light aircraft that are with the times are the diesels, Austro, (ex-)Thielert, and others more.
[ added: plus some adaptations of car engines, like the Viking 110/130 by Mr. Eggenfellner of Subaru fame, but I don't think these are certified ]

[Heston]

Size of the market (tiny cf automotive)
Different requirements, eg power to weight ratioRotax and ULPower are doing some good stuff.
I could argue that you don't hear about engine failures in modern engines exactly because they are more reliable.

[lightonthewater]

Thank you for the information. I realise that old aircraft will have old engines, but given the complications and difficulties in managing them and the drastic consequences of their failure, surely some updating or re-engining would be necessary. If only for the safety of the pilots. It's quite surprising that the authorities haven't mandated this: similar failings with fatal consequences in a road car would have resulted in recalls and compulsory modifications. I assume that economics come into this: cheaper to re-fit a recondition engine of the same type, than a new one. And certifying new engine designs is probably not economic for manufacturers either.

But also, maybe, part of the charm and attraction of flying small planes is perhaps actually mastering the complications and idiosyncracies of each plane, and managing the enhanced risks. Its a world I know very little of, and respect and admire those who can and do those things.

[Heston]

Please don't assume that an engine failure in a light airplane is always going to have drastic and/or fatal consequences (your words). Au contraire, it's an eventuality that pilots are very well trained to deal with and practice frequently. An airplane with a stopped engine can glide down under control to make a perfectly safe landing in many circumstances. There are phases of a flight where dealing with an engine failure is more tricky, like just after take off, but even that is usually survivable.
Let me put it this way. I'd rather have an engine failure in my aircraft at 2000' in the cruise, than a blow out on a front wheel in my car cruising at 70mph in the middle lane of the M6 in the rush hour.

[biscuit74]

'I am interested to see Jan O saying that carburetted Rotaxes don't need carb heat. I have had a couple of instances of rough running which I thought was carb icing, and which application of carb heat - or really carb warm - appeared to cure, in a Eurofox. Why is carb heat not generally required for carburetted Rotaxes please?

[The Ancient Geek]

My 582 has a water heated entrance ring to the carbs. This warming ring is always on, fed by the engine cooling water.
AFAIK this is standard fitting for the 582.

[Fl1ingfrog]

Given that 'cold' and 'warm' are vague terms the Rotax engine runs on a warm air mix and so generally avoids carburettor icing but they are not immune from it. The cylinder heads are liquid cooled maintaining temperatures. Engine failure, of some Rotax engine installations, owing to carburetor icing is not uncommon. Rotax subsequently introduced what is placarded as Carburetor heat although it does not add hot air. The Rotax carb. ht. control shuts off the cold air part of the intake air mixture therefore causing the intake air temperature to rise, hopefully, out of the icing range. The Rotax engine is altitude limited, presumably due to its limitations to cope with the range of temperatures and the needle and float carburettor mixture control limitations for air density.

For power the densest of air possible is required. The colder the air the better and rammed in (even without a turbo) is preferable. Most light engines are not altitude limited other than by performance. Hot air is reserved for when it is required to prevent or dispel icing. The range of temperatures an aircraft regularly experiences is far greater than the automatic systems a car is expected to deal with. Regarding the mixture, an aircraft passes through a vast range of air density and therefore a large range of mixture control is required. There are automatic systems for both of these issues but obviously adding weight, complexity and cost.

[Peter Fanelli]

As a non-pilot,...........

Let me know which auto engine will produce 70-80 % of it's maximum rated power for 2000 hours.
Most auto engines don't even produce rated horsepower until you get up to 5,000 or so RPM, that would require a gearbox or belt
reduction system.

[jonkster]

Paul Bertorelli did a few videos of his opinions about this. I think he has some interesting points and worth looking at.

eg

https://www.avweb.com/multimedia/why-new-aircraft-engine-ideas-rarely-succeed/

also:
https://www.avweb.com/multimedia/why-aircraft-engines-quit/

[B2N2]

It only takes like 40hp to drive a modern car at 60mph while it’s max output is many times that number.
So for the majority of its life a car engine runs at a fraction of what it’s rated for.
In my illustrious career I’ve managed the get the check engine light on twice by spirited driving….in rental cars.

As mentioned before the light airplane market is a mere fraction of the automobile market.
As far as cars keep in mind that a manufacturer often uses an existing engine with some slight modifications or some additional electronic jangles installed.
Point being even in the automobile industry they don’t design a new engine for every new model car and they can recoup R&D cost over literally hundreds of thousands of units if not millions.

There are some “new” aviation engine designs available, even for the retrofit market.
But it’s hard to justify a $70k engine installation on what is a $40k used airplane.
New airplanes even simple ones are eyewateringly expensive even with a prehistoric engine.
Let alone the recertification proces to now install a new engine design.

[Repos]

Just for Info -
https://www.pprune.org/pacific-general-aviation-questions/620904-automotive-v8-engine-conversions-aircraft.html?highlight=Auto+Engines

[Less Hair]

Here is a newly developed V12. Kerosene/Jet-A1 burning and certified.
https://red-aircraft.com/product/

Car engines are tricky to convert as Porsche learned the hard way. However the Thielert, Austro and such are based on a car engine (Mercedes A170) and seem to work finally well.

[lightonthewater]

Thanks to all of you.
Heston: I realise that engine failure doesn't always mean disaster, (far from it) and that aero engines run far harder for much longer than car engines are required to do.
The curiosity I had was more to do with the level of automation (or lack of it). For example, in my old 1960's car I had to start the engine from cold with a manual 'choke' , carefully adjust the mixture as it warmed up, and it would stall immediately if I got it wrong, although the consequences when it did were just inconvenience. And now , thanks to fuel injection, I don't need to bother with this. Fuel injection would remove all risk of problems due to carburettor icing and incorrect mixture, and the potentially more serious inconvenience, as well as alleviating the pilots workload and anxiety levels.
But of course I understand that it's not an option in older aircraft , which seem to form the majority of the private flying fleet, as seen via Prune forums.
However, I guess that safety might be much improved if some way was found to retrofit some level automation.
Thanks again for answering my question.

[Pilot DAR]

Fuel injected engines add a layer of complexity to aircraft systems. Justified sometimes, put undesirable in for other types. One of my first certification projects back in the late 80's was to remove the injection system, and revert to carburettor for the Cessna 185, it was a great simplicity for the plane, and improvement for float operations.

Here is a newly developed V12. Kerosene/Jet-A1 burning and certified.
https://red-aircraft.com/product/

This is one of my present projects, I'll be doing the testing and compliance for this engine into the deHavilland Beaver and STC approval. I'm expecting to be involved in ground run test early in the new year, and hopefully flying it in the spring:

https://www.wingsmagazine.com/sealand-fits-dhc-2-beaver-with-red-a03-engine/

I'm looking forward to this new technology engine (being a VW diesel owner for decades), but it's use in an airplane has presented the need for some complex fuel and electrical system changes, and will require agreement from the authority for special certification conditions.

[Dave Gittins]

My decades of experience is that Lycomings and Continentals, from 1930s agricultural origins,, whether normally aspirated or injected, can often be a pain to get going (requiring techniques my wife would never master if they were needed to start a car) but once started they keep going and (as PF says above) continuously produce their rated power output.

Contrast that with modern fangled motor cars where I have had various problems with engine management systems over the years which require sophisticated (read expensive) diagnostic equipment to investigate. The last car I could properly get to grips with if it failed to start was my 1974 MGB.

[lightonthewater]

The videos suggested by Jonkster answer all my questions and make perfect sense. Basically customer resistance to change, and lack of cash all round.
Very interesting .

Pilot DAR:
Good luck with the project. Will be interesting to see if it changes minds.

David Gittiins:
I have owned cars from those built in the 1950's until the present day (including a Morris Minor, MGB, Landrover, VW and Mercedes). Since then, none built with modern electronics have ever failed to start first time, or given me any trouble at all, although I guess that, if they had failed, it might have been expensive to fix. But maybe I don't drive them hard enough or have just got lucky.

Will get back into my shell: thanks everyone.

[Dave Gittins]

Oh yes :D, I've had minis, 1100's, a Morris1300, an Imp, an MGB and a couple of Mk III Cortinas and fixed 'em no problem until I got an XR3i

Have had engine management box problems on an 02 BMW 320 and an 04 Saab 9-3. The BMW introduced me to "can only be diagnosed by a main dealer" prices of £120/hr in 2008 and a few hundred quid for a new electronic box (couldn't get a spurious one). I'd be heartily upset if I was at 2,000 ft when the engine decided to go into "limp home" mode.

[Pilot DAR]

I had a 1984 Audi Quattro, which I loved. But the engine started to run really rich, to the point it really wouldn't run. It was a very first generation of computer controlled, so I could still mechanically over rule the computer a little, but fixing was needed. The advice I received was: "Remove the glovebox, loosen the computer module behind it to get access to the end of the box. Remove the screw and the end cover, and pour the water out, and let it dry. Reassemble when dry, and run engine." Yup, it worked like a charm! 'Turns out this was a known thing with these cars, which Audi really did not want to admit. The windshield leaked, and dribbled right into the computer. With a shield over the computer box, I drove that car for years, and loved it.

We've been having long discussions about the computer which runs the diesel RED engine being installed in the Beaver. I've directed that the plane will have to have two independent electrical systems, as the RED engine will not run without electricity. There's going to be a lot of analysis and test to demonstrate equivalent safety to simple magnetos!

[Piper.Classique]

That's interesting. I'm flying an Autogyro with a rotax which has been modified to fuel injection. More power, which is nice, but needs electricity. Bigger than standard battery (lithium ion) but even so, losing the alternator means land asap. Which is not a major problem in areas with suitable landing areas, which most places are for a microlight Autogyro, but I'm giving a lot of thought to crossing significant amounts of water or forest. There is still something to be said for magneto ignition.

[PDR1]

The automotive systems that control injector operation/timing, ignition timing, knock-sensing etc include software in what would be (in an aviation application) a safety critical branches of the fault tree. The cost of achieving and demonstrating that the branch is ALARP (let alone the 1 in 10^9 level) is prohibitive as Porsche found out with the Flugmotor. Also, as noted by others, these systems require electrical power to operate. That would necessitate re-engineering the electrical power systems on the aeroplane to the standard required for a safety-critical system because at present the electrical power systems are not designed to a "safety critical" integrity level. That's a big-ticket item in cost terms, and has further knock-ons in increased maintenance costs (as it would introduce maintenance requirements to verify the integrity of these systems is sustained).

The final question is simply one of "why would you want to?". In return for a large capital outlay and increased maintenance costs you would get a small improvement in fuel consumption and a claimed reduction in the risk of in-flight failure. In my ~250 hours of recreational flying the only engine failures I suffered were pilot-induced. None of the recreational flyers I knew had suffered any either. Don't get me wrong - thse failures happen, but non-pilot-induced ones are really rather rare.

PDR

[Fl1ingfrog]

I've directed that the plane will have to have two independent electrical systems, as the RED engine will not run without electricity. There's going to be a lot of analysis and test to demonstrate equivalent safety to simple magnetos!

This mirrors the dual electric ignition systems installed on the Rotax engines. The battery I'm advised is able to supply the engine dual ignition for 3 - 4 hours. Therefore if the alternator failed in flight you then rely wholly on the battery. The battery will have 3 hours plus of life which, in the main, will exceed the remaining fuel endurance.

Remove the screw and the end cover, and pour the water out, and let it dry. Reassemble when dry, and run engine." Yup, it worked like a charm!

A student of mine some years ago owned a garage. A customer came to him one day with a problem with the control board. she had been quoted by a main dealer in excess of £500 to replace it. He had recently bought a large 12" x 12" magnifying glass at a car boot sale for £20. When he flexed the card he quickly found a hairline crack in a solder which he quickly repaired. He charged £250 and she went away very happy.

[Piper.Classique]

The final question is simply one of "why would you want to?". In return for a large capital outlay and increased maintenance costs you would get a small improvement in fuel consumption and a claimed reduction in the risk of in-flight failure.

In my case I didn't actually want it, but I did want that particular mark of Autogyro and the previous owner had fitted the system. I decided that it was worth putting up with the disadvantages rather than revert to carbs

[FullWings]

Could you design and manufacture a light aircraft engine that was lighter, significantly more powerful, and had better economy and reliability than traditional ones? Yes. Would the R&D/certification required make this an expensive undertaking? Undoubtedly. Is there anyone prepared to invest in something like this when ICEs are being replaced by electric systems at an increasing rate? Probably not...

[TheOddOne]

Yes, the future is electric. I've owned an e-Golf for 2 years now, beautiful car, charge it at home from a domestic wall socket in the garage. Only servicing is new tyres.

I'm waiting for the Mk3 electric aircraft, that can do more than just circuits. I need to be able to carry 200kg load over 2 seats and 2.5 hours endurance. Lots of my students are over 100kg...

TOO

[Pilot DAR]

I too am very eager about electric airplanes. I did some initial research on an electric 172 a few years back. It lacked the operational practicality the investors sought. More recently, a more advanced electric airplane program (it has flown) has approached me for certification assistance. I'm eager to support this innovative effort.

[ChrisVJ]

Pilot DAR
Surely the point of using a compression ignition engine is that it runs without external electric power. I understand the need for some external monitoring etc but why would you then design the engine so it needs electric power to continue functioning?

Could not the failure mode be a simple standard functioning?

Years ago I thought the VW aluminum diesel engines would be a suitable base for an aero engine (The 10 cylinder) but any time I suggested it I was shouted down as "That would never work" or "They'd obviously be too heavy." Is the twelve cylinder a custom block or standard from the big saloons?
If that is privileged info I'd understand!

[Fl1ingfrog]

Magnetos are not the most reliable thing in the world so for me the argument to retain them, above all else, is churlish. The developments today are toward an all electric engine.

[lightonthewater]

PDR1:
It is the pilot induced mistakes that I thought might be avoided by fuel injection and modern automatic engine controls. No need for the pilot to worry about mixture control or carburettor icing, for example, and a general easing of the pilot workload in stressful situations. Solutions to the reliability problem can be found, as mentioned elsewhere in this thread: eg duplicate ICU's and batteries that are big enough to supply the electrical needs for them for the whole flight if need be, etc. And, as has also been mentioned before, magnetos are themselves not free of reliability problems either.

But, from what I have read here, its the cost of certification plus the reluctance of customers to try something new that has prevented adoption of automatic engine controls, and, with electric power coming in, its likely to be an academic exercise soon any way.

[Less Hair]

Constantly needing electrical power to keep diesel engines running might look like a bad deal to some people? The beauty of the old engines is their simplicity at the cost of not being as efficient as modern more complex engines.

[Ridger]

Could you design and manufacture a light aircraft engine that was lighter, significantly more powerful, and had better economy and reliability than traditional ones? Yes. Would the R&D/certification required make this an expensive undertaking? Undoubtedly. Is there anyone prepared to invest in something like this when ICEs are being replaced by electric systems at an increasing rate? Probably not...

Nail hit on head I'd say. Porsche's timing with the PFM3200 wasn't ideal and the internet tells me the $75mil programme only produced 80 engines...

I think the advantages of electric propulsion are going to be enormous once it's really sorted.

[Less Hair]

Perfect, this leaves only the batteries to be improved.

[Gargleblaster]

I fly stone-age Pipers, so have to operate carb heat and mixture controls myself.

So, let's say said systems get replaced by automagic systems. For resilience, you´d need two of each systems. You´d need an indication to the PIC of one system malfunctioning. Likewise of both malfunctioning. You´d need checklist procedures for what to do when that occurs. Not worth it. Keep it simple. My lawn-mower has run for 35 years w/o problems.

Hahaha, I'm in the software industry myself, and am responsible for hundreds of thousands of peoples assets and I know what can go wrong.

[NutLoose]

We've been having long discussions about the computer which runs the diesel RED engine being installed in the Beaver. I've directed that the plane will have to have two independent electrical systems, as the RED engine will not run without electricity. There's going to be a lot of analysis and test to demonstrate equivalent safety to simple magnetos!
Pilot DAR is offline Report Post (https://www.pprune.org/report.php?p=11146932)

And here a salutary tale of having an engine or two reliant on wiggly amps.

https://www.aviationconsumer.com/industry-news/fate-1-fadec-0/

[NutLoose]

As for Lycoming or Continental, why change what works, they are pretty much bullet proof, agricultural in a way yes, but solid, I’ve seen the rare aircraft return having shed their cylinder heads, as bad as that seems it was still running and a cylinder change and top up of oil was back in service.

[jonkster]

In traditional piston engined aircraft, the most unreliable component (and most likely cause of engine stoppage) , I would suspect by a considerable margin, is one component widely used in the fuel and engine management systems, the pilot.

I wonder if the same faulty component will be repurposed for use in future electric aircraft? If so I suspect it may also become the weak point in that technology as well.

[MarcK]

In traditional piston engined aircraft, the most unreliable component (and most likely cause of engine stoppage) , I would suspect by a considerable margin, is one component widely used in the fuel and engine management systems, the pilot.

I wonder if the same faulty component will be repurposed for use in future electric aircraft? If so I suspect it may also become the weak point in that technology as well.
Extrapolating from other requirements... just require two of them.

[Pilot DAR]

And here a salutary tale of having an engine or two reliant on wiggly amps.

Yes, this factored in the foremost of my thinking as I plot the systems for the diesel Beaver. I was involved with the testing and certification of the Lycoming powered DA-42, and these systems discussions were peripheral to that. When I flew the Theilert DA-42's this was on my mind, but they behaved fine (save for one failed turbo controller).

But the absolute requirement for electricity introduces a absoluteness of requirement which has had design compliance wiggle room up until now....

I have a computer fuel injected (Bosch) powered Polaris Ranger utility vehicle, and what a pain that system is! I wish I could convert it back to carburetted! It has never run well, and one broken wire ('cause Polaris made the engine harness too short) becomes a huge troubleshooting chore. At least Polaris' own service manual tells you that most engine problems are electric - yeah! If they'd designed their wiring better, they would need so much repairing!!! I really miss my carburetted, no computer Polaris Sportsman ATV - so what if I had to use a choke!

[Matt48]

Compared to a carburettor, fuel injection has many more parts that 'may' fail, a carburettor is a simple thing that works fine most of the time, carb ice can be a problem, that's why the pilot is furnished with a carb heat control and is supposed to be trained in its' function and operation.
The GA industry is not flush with cash, and updating an Aero engine is not the same as Toyota or Mazda bringing out a 'new and improved' model, it is a very time and money intensive operation to 'prove' a new design is reliable and fit for purpose, that's why aero engines look like they come from the 30's and 40's , because it is so hard to change an approved design.

[blind pew]

I was offered a self launching Silent motor glider by a retired KLM captain. I test flew it after a full briefing from the owner from Vinon and into the Alpes de hautes Provence; what the owner omitted to tell me that there was an ignition fault which would occasionally stop the engine accelerating above idle. A simple on off switch which interrupted the alternator field had been installed on the instrument panel.
I got very low at one stage and decided to use the engine which isn’t the easiest operation nor the least stressful. It extended, started but wouldn’t produce power until I played a one armed wallpaper hanger with the throttle and the switch.
The glider went back into the box and he flogged it to some other victim. I never attempted to use a glider motor in the mountains again.
Apparently the fault existed on all of that mark of motor glider.
Thanks Nic.
PS I was asked to become a partner and instructor on a series of microlight aircraft but turned it down; my would be partner crashed with the authorities’ test pilot after the engine failed to start.

[Peter Fanelli]

I realise that old aircraft will have old engines, but given the complications and difficulties in managing them .....

I've spent thousands of hours flying turbocharged light twins. with both Lycoming and Continental engines.
They are not at all complicated or difficult to manage at all.......

Provided the person with that responsibility puts away the camera and concentrates on being a pilot instead of working on his next you tube chapter.

[Heston]

Provided the person with that responsibility puts away the camera and concentrates on being a pilot instead of working on his next you tube chapter.

Hooray! Somebody agrees with me :)
Also true of students you tubing their 'journey' to being a pilot. I just want to say that their journey would be quicker and cheaper, and they'd maybe end up being better pilots. But what do I know?

[Big Pistons Forever]

I think the transition to electric trainer is a done deal, it is only a matter of how long it is going to take to make the switch. Practical electric GA touring aircraft is a different story as the challenge of getting enough range to be useful, is considerable. However car companies are investing tens of Billions on battery technology so progress is inevitable.

I truly believe GA gasoline engines have no future so significant development of them is pointless. An interesting question is what to do with vintage aircraft. Harry and Megan drove off on their honeymoon in an electric Jaguar E type, is there an electric Chipmunk on the boards ?

[Heston]

The future for ground based transport in the long term isn't electric, it's hydrogen.

[Big Pistons Forever]

The future for ground based transport in the long term isn't electric, it's hydrogen.

The market has spoken and it is battery electric technology.

[Uplinker]

@lightonthewater,

Like you I agree it seems crazy that in this day and age we are using the most basic engines in light aircraft, whose only "automation" is mechanical spark timing advance and fuel mixture tracking with mass airflow into the engine, (within the carburettor). Having to adjust the mixture and apply carburettor heat manually is incredibly crude - and not a long way on from early cars, in which this as well as ignition timing also had to be adjusted manually and double de-clutching had to be performed by the driver.

Modern car engines are so automated now that they behave almost like electric motors: push one pedal for go, another for stop. Nothing else need to be thought about by the driver - not even gears in modern autos - leaving the driver to concentrate fully on the road and the driving task.

Modern cars are also incredibly reliable and will start on the first turn of the starter motor in any weather - without us even having to sit in the car during starting ! Who else remembers the "dawn chorus" in the '70's, of people trying to start their cars on cold frosty mornings, and then warming them up? - I have had similar problems trying to start Cessna 152's on similar cold mornings.

But, as others say, electronics would need to be backed-up in an aviation setting, and supplied by a backed-up power source, with the attendant complication of electrical busbars and contactors etc. Atmospheric conditions at even a few thousand feet agl can be much more challenging than those at ground level. So much as I hated the crudeness of having to do the mixture and carb-heat 'donkey work', it is probably here to stay unless one starts paying millions for light aircraft instead of hundreds of thousands.

[Less Hair]

The market has spoken and it is battery electric technology.

The market has spoken to not want electric technology as of today. This is why electric cars get massively subsidised. I agree with Heston that hydrogen is much more promising given the slow progress in battery performance combined with their very high weight. Possibly we might end at some combination of liquid or gaseous fuel that get converted to electric energy used by electrical engines.

Whatever we use to store the energy the energy itself must be generated "green". This is why the battery mantra is leading nowhere.

[ShyTorque]

And here a salutary tale of having an engine or two reliant on wiggly amps.

https://www.aviationconsumer.com/industry-news/fate-1-fadec-0/

Reliance on electrical power is the case on some gas turbine helicopters, too, where there is no reversion to manual fuel control. It’s very important to ensure that the battery is fully charged and in the case of a double generator failure, the aircraft needs to be landed ASAP before the charge runs out.

[Big Pistons Forever]

The market has spoken to not want electric technology as of today. This is why electric cars get massively subsidised. I agree with Heston that hydrogen is much more promising given the slow progress in battery performance combined with their very high weight. Possibly we might end at some combination of liquid or gaseous fuel that get converted to electric energy used by electrical engines.

Whatever we use to store the energy the energy itself must be generated "green". This is why the battery mantra is leading nowhere.

This is a VHS vs BetaNax argument. It dId not matter that BetaMax was superior technology all that mattered was the industry made a decisive shift to developing VHS machines. Similarly Industry and governments are investing heavily in Battery technology and charging infrastructure. Like I said the ship has sailed and we are not going back except in certain niche areas, which aviation may actually be one with respect to the future of airline aircraft propulsion. I just don’t see that for GA

[Less Hair]

Electrical aircraft will need range and need to be lightweight. Until then no way except for niche applications. Like the Pipistrel Velis.
Electrical cars will need to be autonomous driving including driverless to self drive to automated charging stations whenever needed. Then they need to come back fully charged to get to a certain range and usability. We are not there yet. We are just converting inefficient fuel burner SUVs to inefficient battery SUVs.

[flyingorthopod]

I'm not sure what the future is, I.suspect a mix of battery and fuel cell cars to come
However battery electric cars are hugely more thermodynamically efficient than internal combustion unless the electricity comes from coal or gas, which we should have ditched years ago. Battery technology will get there.

[NutLoose]

Yes, this factored in the foremost of my thinking as I plot the systems for the diesel Beaver. I was involved with the testing and certification of the Lycoming powered DA-42, and these systems discussions were peripheral to that. When I flew the Theilert DA-42's this was on my mind, but they behaved fine (save for one failed turbo controller).

But the absolute requirement for electricity introduces a absoluteness of requirement which has had design compliance wiggle room up until now....

I have a computer fuel injected (Bosch) powered Polaris Ranger utility vehicle, and what a pain that system is! I wish I could convert it back to carburetted! It has never run well, and one broken wire ('cause Polaris made the engine harness too short) becomes a huge troubleshooting chore. At least Polaris' own service manual tells you that most engine problems are electric - yeah! If they'd designed their wiring better, they would need so much repairing!!! I really miss my carburetted, no computer Polaris Sportsman ATV - so what if I had to use a choke!

They rectified the problem by adding extra batteries to supply the Fadec in an emergency, see

http://support.diamond-air.at/fileadmin/uploads/files/after_sales_support/DA42_Twin_Star/Service_Bulletins/SB42-050-O-r1-ECU-Backup-Batt-incl-_WI-Rev2-incl-EASA-AD.pdf

[PDR1]

The future for ground based transport in the long term isn't electric, it's hydrogen.
Great. Where are you going to get the hydrogen from? It may be different in your part of the world, but around here hydrogen mines are a little thin on the ground...

PDR

[PDR1]

They rectified the problem by adding extra batteries to supply the Fadec in an emergency, see

http://support.diamond-air.at/fileadmin/uploads/files/after_sales_support/DA42_Twin_Star/Service_Bulletins/SB42-050-O-r1-ECU-Backup-Batt-incl-_WI-Rev2-incl-EASA-AD.pdf
Most battery failure modes are age and environment related, so unless one battery is explicitly required to be half the age of the other there's a high-ish probability that both will be dead on that cold winter morning when the driver wants to fly.

I guess people missed the fact that the cause if the DA42 crash wasn't the battery or the engine failures - it was the driver. The manual said starting both batteries from a ground power unit was verbotten, but the driver knew better. I can see no justification for believing that drivers will pay attention to the battery states and condition monitoring requirements that are an inherent part of this solution. You can always tell a pilot, but you can't tell him much...

PDR

[Less Hair]

Great. Where are you going to get the hydrogen from?
From the same sources you load your batteries from. "Green" hopefully.

[Heston]

Great. Where are you going to get the hydrogen from? It may be different in your part of the world, but around here hydrogen mines are a little thin on the ground...

PDR

https://orsted.co.uk/energy-solutions/renewable-hydrogen
First website I found when Googling.

Batteries have a big problem - strategic access to the raw materials needed to make them.
It's still early enough for the investment in battery technology to be a blind alley. Interestingly, Johnson Matthey, a UK materials company, have just ditched their development of materials for batteries in favour of hydrogen (their big customer is the automotive industry)
https://matthey.com/en/news/2021/battery-materials-announcement

[Uplinker]

"Great. Where are you going to get the hydrogen from?......PDR"

You 'split' sea water into its constituent oxygen and hydrogen gases using electrolysis. We did it in chemistry at school. You just need sea water and electricity connected to two electrodes submerged in the water. A chemical reaction takes place and the hydrogen gas accumulates above the negative electrode, the oxygen above the positive.

Use wind turbines, solar panels or tidal flow turbines to provide the electricity to split the seawater, and you produce hydrogen.

Note: Sea water rather than pure water because the salts in the seawater make it electrically conductive.

[ShyTorque]

This is a VHS vs BetaNax argument. It dId not matter that BetaMax was superior technology all that mattered was the industry made a decisive shift to developing VHS machines. Similarly Industry and governments are investing heavily in Battery technology and charging infrastructure. Like I said the ship has sailed and we are not going back except in certain niche areas, which aviation may actually be one with respect to the future of airline aircraft propulsion. I just don’t see that for GA

A problem for larger ‘lectric aircraft is that unlike liquid fuelled ones they don’t “burn off” weight as fuel is used. This will cause design challenges because as we know, larger aircraft can take off at a higher all up weight than at which they can land. Undercarriages will have to be stronger and heavier, reducing payload.

Also, it won’t be possible to trade off fuel uplift for extra performance demands, such as at high density altitudes or short runways.

As always, design is a compromise.

[Less Hair]

This permanent overweight operation doesn't bode well with the short ranges of battery powered aircraft.

[PDR1]

https://orsted.co.uk/energy-solutions/renewable-hydrogen
First website I found when Googling.


"Great. Where are you going to get the hydrogen from?......PDR"

You 'split' sea water into its constituent oxygen and hydrogen gases using electrolysis. We did it in chemistry at school. You just need sea water and electricity connected to two electrodes submerged in the water. A chemical reaction takes place and the hydrogen gas accumulates above the negative electrode, the oxygen above the positive.

Use wind turbines, solar panels or tidal flow turbines to provide the electricity to split the seawater, and you produce hydrogen.

Note: Sea water rather than pure water because the salts in the seawater make it electrically conductive.

That's my point - hydrogen is not an energy source, merely an energy transfer mechanism. You need energy made by some other means and then you "transform" it into hydrogen in a process that's inefficient and produces waste products (salts). Schoolboys say that burning hydrogen in internal and gas-turbine engines is "clean" because the exhaust is just water. This is (of course) not actually true. when you burn hydrogen in air at the pressures and temperatures you need for effective propulsion you also end up burning the nitrogen in the air and producing significant quantities of the nitrates which are ALSO one of the concerning pollutants. You could use the hydrogen in fuel cells for an electric final drive, but that's completely dependant on rare metal catalysts (a scarce and non-renewable material), making the problem worse rather than better - these materials make the platinum used in catalytic converters (which is already running into supply problems) look positively abundant. So if you're using the same generating plants as the grate unwashed are using for heat, light, cooking and social media then you can expect to join a queue. If they are being told they must have a cold house and can only watch strictly for 2 hours a day to conserve electricity I don't think aviation will be high on their list in that queue, and recreational aviation will be right up there with politicians on their list of hate objects.

Hydrogen can't be liquified at normal temperatures, so it has to be stored in pressurised bottles. The usual parametric is that to store hydrogen at a pressure that gives a third of the energy per litre of petrol needs "tanks" that will weigh twice the weight of the hydrogen being contained. The equivalent number for petrol is about 5% (for three times the amount of "effective fuel"). With all of this factored in the use of hydrogen fuel comes out pretty close to batteries in terms of MTOW limits with considerably fewer safety issues. Yes, the weight reduces with use, but not by anywhere near as much as it does for petrol because the basic fuel is lighter and the tanks themselves are [massively] heavier. Hydrogen does have the advantage of quicker refuelling, but has much more complicated fuelling equipment requirements.

I'm not saying it's not the answer - merely that it's a much more complex and nuanced question than most of these simplistic "we can use hydrogen and everything will be the same - everyone else is just to thick to see it blah blah" rants suggest.

PDR

[DuncanDoenitz]

A problem for larger ‘lectric aircraft is that unlike liquid fuelled ones they don’t “burn off” weight as fuel is used. This will cause design challenges because as we know, larger aircraft can take off at a higher all up weight than at which they can land. Undercarriages will have to be stronger and heavier, reducing payload.

Also, it won’t be possible to trade off fuel uplift for extra performance demands, such as at high density altitudes or short runways.

As always, design is a compromise.

For hydrogen fuelled aircraft, of course, the opposite is true; as fuel burns off, they become heavier.

Probably.

[Jim59]

For hydrogen fuelled aircraft, of course, the opposite is true; as fuel burns off, they become heavier.
Probably.

Probably only after the pressure in the tank falls below about 10 bar. Starting at 700 bar, say, it will become lighter as the fuel is used.

[Heston]

You will note from my earlier post where I introduced the hydrogen topic that I said for ground based transport. This is because the extra weight compared to petrol etc. doesn't matter too much.
Hydrocarbon fuels have a very good specific energy density - ie energy available for weight. Much better than current battery technology and hydrogen (glad to see that PDR1 has done a bit of research now). That's one reason why they are going to be so hard to replace in aircraft.

[Fl1ingfrog]

Whether all-electric engines or hydrogen powered units wins the day is going to be determined by development. The developments of potential will not be done by aviation manufacturers because the costs are too large. The adoration of the squeeze and bang engines supplied by clung click magnetos and using fuel that may destroy the earth is misplaced. We have got to look forward to engines that are earth kind and don't fall to bits over a short time as the current engines in use do. My mentors hammered into me the realism of engine failure and the need for a high level of skill in forced landing; this had been very real for them with the current engines.

The failures of modern electrical systems such as Pilot DAR's vehicle ECU that could fill with water with no means to escape. Once drained the unit was good and reliable enough to be used for a further decade and more. The DA42 with a back up battery that could not be recharged nor replicate the performance of the main battery, even for a short period. Not even a pilot alert warning was included in the design. Both of these is blinkered poor and sloppy design. To blame the pilot for not knowing the manual back to front is unfair and not human. The DA 42 aircraft had an external power socket to permit a start of both engines. Although the manual instructs that the external power should be disconnected after the first is started it does not warn that the second engine should not also be started the same way. It does not warn that you must wait for the flat battery to recharge sufficiently to a minimum level before takeoff in order to be relied upon later.

James Reason developed the 'Swiss Cheese' theory for a very good reason. Modern engineering should not be dissed: cracked engine shells, cylinder heads detaching and failing magnetos are things of the past and sadly of the present. Design isn't just about getting things to work economically, it is also about the operation. The worlds manufacturing Industry is well aware of this while the aviation industry still demands its customers to gain the equivalent of a master degree in the use of its products and also foresee events that they can't be bothered to warn you of.

[PDR1]

Hydrocarbon fuels have a very good specific energy density - ie energy available for weight. Much better than current battery technology and hydrogen (glad to see that PDR1 has done a bit of research now).
On a point of information - PDR1 does not need to be patronised* on this topic, and nor does he need to do any research because PDR1 is actually involved in studies around future aircraft propulsion systems and is thoroughly familiar with the pros and cons of the different options. All that PDR1 is trying to do is get across the point that it's not a matter of "simply switch to hydrogen and the job is done, as any idiot can see" because only idiots see it that way. In shear weight/size/performance terms there is as good a case for revisiting the nuclear propulsion concepts first played with in the 1950s (especially since the intervening 60 years of experience with micro-reactors in naval applications has massively matured the enabling technologies). It's unlikely to happen because of public perceptions about safety (as much as anything else), but then the hydrogen fuel lobby haven't yet given an answer on how the BLEVE risk which would make every hydrogen-fuelled vehicle (car or aeroplane) a potential FAE of almost atomic-bomb proportions.

PDR

* For Heston's benefit - "patronised" means "talked down to"

[Pilot DAR]

Calm please... There is a lot to learn, as we pursue less polluting flying, I'm sure that we can all learn something....

If the non aviation portion of society continues to notice that aircraft are the only means of transport not going green, we will have less and less sympathy (and extension of the availability of gasoline and jet fuel). Uunifying, and doing our best is the most wise path to sustaining our industry.

[Heston]

Great. Where are you going to get the hydrogen from? It may be different in your part of the world, but around here hydrogen mines are a little thin on the ground...

PDR

For PDR's benefit, can I point out that this was the first patronising post?

Batteries and hydrogen are both "only" energy storage and transfer mechanisms. The assumption all along is the original source of the energy will be green, from wind or whatever.
But PDR makes a good point - I agree that it is likely that hydrogen tech won't work in aviation because of the weight issue, whereas we may get sufficient specific energy density from batteries eventually.
The Catch 22 though is that that will only happen if development continues for automotive use. If ground transport goes hydrogen, as I believe it will, then development of battery technology will grind to a halt, leaving aviation without a solution.
The recent demonstration of artificial "green" fuel for aviation use may turn out to be the answer.

I was doing research into alternative battery materials in the 1970s, so I think I know that progress has been slow. Hydrogen is pretty recent by comparison.

[PDR1]

I accept that that there was good patronage on both sides (to quote Agent Orange).

I'm not particularly promoting batteries either, just (as I said) making the point that it is not a clear binary debate. Tracing the value-chain from energy source to power developed in both cases shows that the battery line in more efficient and has lower overall emissions, but that doesn't inherently make it ideal because of its fundamental limitations in terms of range, turn-around time etc.

I think a rational solution would look to tap into the resource which is both carbon neutral and depressingly renewable - so we should consider whether a propulsion system fuelled with rendered climate-change protester oil might not be the best solution. I fear there would be no lack of volunteers to work in the climate-protester rendering plants.

PDR

[Big Pistons Forever]

Step changes in aircraft were always engine driven

1) A piston engine with a high enough power to weight ratio to allow flight: The Wright bothers engine
2) A piston engine with enough power to give meaningful performance: The Gnome rotory
3) A piston engine that can produce enough horsepower to make air transport practical. The P&W and Curtis 9 and 18 cylinder radial engines
4) The first jet engines
5)???

[Heston]

This is true - if steam engines had been lighter the first powered heavier than air flight could have happened long before 1903. We could have had steam punk style aircraft; that would have been cool.
Is an anti-gravity drive needed next?

[PDR1]

3) A piston engine that can produce enough horsepower to make air transport practical. The P&W and Curtis 9 and 18 cylinder radial engines


I think Rolls Royce, Napier, Bristol and DeHavilland, Hispana, BMW, Junkers and quite a few others might be coughing & spluttering a bit at that.

PDR

[Jan Olieslagers]

Instead of discussing which is the best or most likely alternative for fossil fuels, we had better realise that energy, of whatever kind or origin, is rapidly becoming more and more rare and thus more and more expensive. It seems obvious to me that activities that rely on large quantities of energy will become - as they once were - the exclusive playground of the well-to-do. Which includes private flying, motorboating, karting, and several more.

[Big Pistons Forever]

I think Rolls Royce, Napier, Bristol and DeHavilland, Hispana, BMW, Junkers and quite a few others might be coughing & spluttering a bit at that.

PDR

Nice try but the vast majority of piston engined airliners had American radial engines. European protectionism allowed more expensive and less reliable engines to see service but the production numbers tell the tale. Particularly post WW2 the vast majority of airliners in service were powered by American engines including those used by every major European.

In any case it doesn’t matter, the point remains that the reliability and efficiency of the big radials allowed practical passenger air travel for the first time.

[GWYN]

Actually, Heston, see: https://en.wikipedia.org/wiki/John_Stringfellow

In 1848 Stringfellow achieved the first powered flight using an unmanned 10 ft wingspan (https://en.wikipedia.org/wiki/Wingspan) steam-powered monoplane built in a disused lace factory in Chard, Somerset.

[Maoraigh1]

When fossil fuel was first used, the idea that enough CO2 would be produced to affect the Earth's climate would have been unbelievable.
Plants use CO2 to make their food. They excrete O2.
is there any possibility that hydrogen from water could increase the atmospheric O2, before it is converted back to H2O?
This could have an impact on fires and on respiration.

[B2N2]

Although the manual instructs that the external power should be disconnected after the first is started it does not warn that the second engine should not also be started the same way. It does not warn that you must wait for the flat battery to recharge sufficiently to a minimum level before takeoff in order to be relied upon later.

I believe you are incorrect.
I’d have to dig into my pile of old manuals but the DA-42 1.7 did come with a warning not to start both engines with external power.
I believe also the Battery Master switch was never turned on so the electrical system was running off the generators without the benefit of the buffering function of a battery and the ECU’s “blinked” as a result of the brief fluctuation as the electric hydraulic pump kicked in.
The backup batteries installed as a result of that pilot induced incident did not have to be rechargeable as per EASA certification.
The original Thielert 1.7L was and is still my favorite engine for that airplane.

[horizon flyer]

What a subject, pages could be written, yes engines are not as reliable as they could be certainly Lycomings have many uncorrected design flaws, so that many never make TBO, without some work.

To make Hydrogen with electricity needs clean water not sea water and platinum for the electrodes ( have to mine an asteroid for the amount needed)
at the moment it is made from natural gas which produces 9kg of CO2 for every Kilo of it. So not so clean.
Also as it costs about a million pounds to build a Hydrogen filling station, I don't see airfields rushing to install them.

Electric motor/battery combination has to be consider as a package and compared to the weight of ICE and fuel together to be compared.
So the extra weight of the battery can be offset against a lighter electric motor. So when batteries reach about 2.5 Klw/hour/Kilo then liquid fuel is dead.
Note there is a 300hp 15kg electric motor on the market but it does rev at 20,000rpm so the gear box would add extra weight.

A bit off subject Lycoming have a certified electronic Mag on the market and are fitting one on new engines along with a normal mag as backup
this means ships power is required to run but it does produces a higher spark voltage and cheaper automotive spark plugs can be used.
Improves starting and more reliable. The next item to improve things would be dumping the 14 volt lead acid battery for a LiFePo4 Lithium (they don't burn)
but would would require a small redesign of the alternator regulator for the correct charge voltages and must have overvoltage protection.
These changes are relatively low cost but I believe would improve reliability.

[megan]

In my estimation the test of an engine is its fuel efficiency, the fuel burned for each horsepower produced, crunched some numbers and a Lycoming O-720 at 75% best economy comes out at 34.44%, R-3350 at the same setting 35.71%. Pretty good I'd say, without hanging electricity dependent bits off of it. Haven't been able to find car figures to compare, I've read that all the do dad electronics on todays average car has more to do with meeting pollution requirements than improving economy

[Jan Olieslagers]

There is no conflict between fuel economy and pollution, at least not as regards CO2: if you burn 20% more fuel then you'll produce 20% more CO2. Electronics do help to optimise the process though, reducing CO and other things even worse than CO2.

[Heston]

I think Rolls Royce, Napier, Bristol and DeHavilland, Hispana, BMW, Junkers and quite a few others might be coughing & spluttering a bit at that.

PDR
Yes indeed! Or, not coughing and spluttering but running smoothly producing lots of horse power.
The first aircraft to cross the Atlantic was powered by Rolls Royce engines. Not a Wright engine.

[PDR1]

I've read that all the do dad electronics on todays average car has more to do with meeting pollution requirements than improving economy

Not actually true, I'm afraid. Most modern automotive engines use "stratified charge" combustion to get the efficiency - a concept which generates layers of lean and rich mixture inside the combustion chamber to get the lower consumption of the lean-burn with the higher speed of combustion in the rich mixture. It requires very precise metering of injection settings (duration and timing), ignition timing and (in turbocharged engines) cylinder pressures. Parameters like cylinder and intake air temperatures are part of the equation along with throttle demand and demand rate, rpm etc. This is even more true for diesels than for petrol engines (other than the ignition timing, obvs!). Without the "electronic do dads" the fuel consumption would be typically 20-40% higher, especially on short trips. The reduced fuel consumption improves most of the emissions but the more aggressive combustion (higher pressures and temps) does tend to increase the production of nitrates - these are addressed by other means.

PDR

[Heston]

Nice try but the vast majority of piston engined airliners had American radial engines. European protectionism allowed more expensive and less reliable engines to see service but the production numbers tell the tale. Particularly post WW2 the vast majority of airliners in service were powered by American engines including those used by every major European.

In any case it doesn’t matter, the point remains that the reliability and efficiency of the big radials allowed practical passenger air travel for the first time.
I'm not qualified to comment on the relative technical merits of air cooled radials vs water cooled inline engines. But post-war, the dominance of the US engine manufacturers was much more to do with the size of their domestic market than anything else. Continental north America is vast and there were relatively few railways - ideal for air transport.
Sort of the same point that used about VHS and Betamax.
And by then RR at least was focused on jet propulsion.

[Heston]

Actually, Heston, see: https://en.wikipedia.org/wiki/John_Stringfellow

In 1848 Stringfellow achieved the first powered flight using an unmanned 10 ft wingspan (https://en.wikipedia.org/wiki/Wingspan) steam-powered monoplane built in a disused lace factory in Chard, Somerset.
I'd forgotten about Stringfellow (born in Yorkshire, naturally) - thanks for the reminder. Awesome chap.
The museum in Chard is well worth a visit by the way.

[GWYN]

I'm sure you're right about the museum. To my shame even though I actually remember it being established, rather a long time ago, and lived very close for a long time, I have never visited it.

(born in Yorkshire, naturally), yebbbuuutt......it all happened in Chard!

[horizon flyer]

Actually the first aircraft to fly with people aboard 3 crew was steam powered burned avture and had 2 axis gyro controlled auto pilot for yaw and pitch.
Date was 30 of July 1896 in London and flight was longer than the Wright flyer that needed a catapult launch system. It was called the Maximum Flyer
designed by Sir Hiram Maxim designer of the first fully automatic machine gun made by Vickers and silencers for IC engines and guns. There are pictures on the web to back this up. So the Wright flyer was not the first.

[mikehallam]

Shureley must be shome mistake with the date and it's really April 1st.
Actually the first aircraft to fly with people aboard 3 crew was steam powered burned avture and had 2 axis gyro controlled auto pilot for yaw and pitch.
Date was 30 of July 1896 in London and flight was longer than the Wright flyer that needed a catapult launch system. It was called the Maximum Flyer
designed by Sir Hiram Maxim designer of the first fully automatic machine gun made by Vickers and silencers for IC engines and guns. There are pictures on the web to back this up. So the Wright flyer was not the first.

[PDR1]

I assumed this was a tongue-in-cheek post as it's a fairly well established myth. Maxim (and Ader, and many others) built things in the latter years of the 19th century which became airborne (usually just briefly) but were not practicable air craft in that they had not developed effective means of control so they could not sustain flight and could not choose to fly to/from specific places. One can certainly argue that the usually stated date of Dec17th 1903 is a bit dubious because that flight was really just an extended glide, but in the subsequent weeks they achieved flights that climbed above the launch point and flew around for reasonable periods before landing in a specific place chosen by the pilot. The Wright Brothers may not have made the first "flight", but they did fly the world's first practicable air craft and their real contribution was in establishing the basics of CONTROLLED flight.

Maxim's vehicle was huge and uncontrollable - it crashed. Ader's vehicle was only capable of flying in ground effect for a few dozen yards, and it crashed. Most of the others didn't even achieve that. Maxim's aeroplane is claimed to have had two 180bhp steam engines. Even with today's technology we'd struggle to get the boilers, combustion chambers (fireboxes), water tanks etc down to a weight that might have been aviationable - I would regard a claim that this was done on victorian times with some scepticism. As for the "2 axis gyro controlled autopilot" I would find it surprising that (had it existed) such an invention never found its way into ships and airships. But then I'm just a cynic.

PDR

[horizon flyer]

The Maxim flyer was being tested down a 1800 ft rail track with a hold down system over the undercarriage wheels, due to the high lift of the design the right hand wheel axle failed and the machine became airborne but out of control, as the righthand prop had been damaged by debris, it yawed right and crashed. It did have steam powered gyro stabilised yaw by differential throttling of the props and pitch controls. The are pictures of it at the crash site with the then prince of Wales in the photo.

[mickjoebill]

An alternative?
New GT50 turbine shaft engine designed from the ground up as part of a new helicopter design.
35 gallons per hour, 400HP continuous 440HPH takeoff.
Comparatively low maintenance costs.
5000 hours or 20,000 cycles.

https://www.hillhelicopters.com/gt50-engine
mjb

[skridlov]

Yes, the future is electric. I've owned an e-Golf for 2 years now, beautiful car, charge it at home from a domestic wall socket in the garage. Only servicing is new tyres.

I'm waiting for the Mk3 electric aircraft, that can do more than just circuits. I need to be able to carry 200kg load over 2 seats and 2.5 hours endurance. Lots of my students are over 100kg...

TOO
"Only servicing is new tyres."
I didn't realise that electric cars contained no components requiring lubrication. Or non-maintenance brake systems. Remarkable...

[Andrewgr2]

"Only servicing is new tyres."
I didn't realise that electric cars contained no components requiring lubrication. Or non-maintenance brake systems. Remarkable...
Just put two new tyres on my electric car after two years and 29000 miles. There is no lubrication or any servicing specified or required to maintain the warranty. A brake check soon seems like a good idea but since virtually all braking is regenerative I’d be looking for seized pistons rather than worn pads. The legacy manufacturers make a lot of money from servicing and don’t want to lose it.

[Heston]

https://youtu.be/a717YZnhQ-s
Paul Bertorelli's take on electric airplanes (sic).

[Pilot DAR]

I quite agree with Paul Bertorelli's video. Generally, when he speaks, I listen. He touched on the highpoints, which was great, though many of the points deserve a deeper dive, as people embrace the concept.

Electric planes are someone's future. Not us old guys, though probably some of the young pilots who are just getting started. It's going to be very different. But there'll be a lot more trip planning, with shorter trips, as needed to charge the plane to get back home will certainly be a planning factor. I've worked one electric conversion project (C 172) which did not come to be, as the business model is terrible for a training plane which has to charge for many hours between half hours flights. I have involvement in another electric conversion approval project next year, it has more future.

But these aircraft with many propellers are going to require new certification basis thinking. It was 2006, when I attended a presentation on the certification special conditions required to approve a civil tilt rotor aircraft. Though a very viable concept, there are some things that tilt rotor/multi motor aircraft will do very poorly. Top of mind is power off landings. Every presently certified airplane and helicopter is required to demonstrate landing with no power. It's ugly for some, but they can all do it. I think it's a stretch that these new concept aircraft will be able to. Perhaps the public will accept this reduction in the most basic flying capability, but after the first few "falls" (at best under a parachute), there'll be more discussion.

I'm sure that there's an electric car in my future, I'm less sure about the new concept aircraft, but, my mind is open.....

[Fl1ingfrog]

Paul Bertorelli's analysis is interesting but surely history has taught us that predictions into the future is always way off. To use the drawbacks of current battery technology is pointless. I remember visiting a major companies computer room extensively rigged with air conditioning and purification ducts . Rows of 7ft high cabinets with spinning reel to reel tape. The power was boasted as being 64k. Well', we now own mobile phones in gigabytes which we can hold in the palm of one hand. Our first 1950s TV had a tiny black and white screen with a magnifying glass bolted onto the front. We now expect to make video calls to anywhere in the world on our phones. We can store numerous full feature films to watch in our hotel rooms.

I think it fair to say that no one foresaw any of our present nor how we have come to both evolve and use these technologies. We shouldn't think of using the future aircraft battery power as we do with tanks of petrol. The research into battery size, capacity and output is being developed in earnest for all kinds of purposes. Think then of a battery which is the size of the palm of your hand and that will run your aeroplane for days and enable many other things, so far not thought of, than do our aircraft petroleum tanks.

[Pilot DAR]

I agree that there will be battery advancements we can't imagine right now, which will get batteries to petroleum like energy density. And, with that advancement in energy density will come an even greater aversion to that density from a safety perspective. 787 batteries, Teslas which self ignited a few days after an accident in the impound lot, people's phones getting really hot and smoking. With new solutions also come new things to consider fro safety. Before electric aircraft carry people for hire, they'll have to be certified. At present, there is no standard for such certification, so it'll have to be developed and agreed regulator and industry. When I have trouble getting the regulator to allow me to approve the installation of an instrument with an internal battery, because I cannot demonstrate the inherent safety of that battery, we're a way's away from the regulator being comfortable certifying a primary power battery bank. We'll get there for sure, but it's not just around the corner....

[horatio_b]

Fossil-fuel free domestic flights in Denmark and Sweden by 2030 apparently.....
https://www.bbc.co.uk/news/world-europe-59849898

[Fl1ingfrog]

When I have trouble getting the regulator to allow me to approve the installation of an instrument with an internal battery, because I cannot demonstrate the inherent safety of that battery, we're a way's away from the regulator being comfortable certifying a primary power battery bank. We'll get there for sure, but it's not just around the corner....

We need new redesigned regulators for the future too. Why is it OK to have filthy and noisy petroleum engines that catch fire and blow up on a regular basis. Fuel starvation is an enormous contributor to fatal accidents. We train our pilots to treat the fuel gauges with extreme caution. Most gauges rely on a sender that is exactly the same as those fitted in my toilet cisterns. We live with all these dangers though because of the benefits they bring. Everything has its price.

I'm reminded of a PPL who told me that he had owned aeroplanes for over 40 years both new and second hand but he'd never owned one that had all things working. I remind my students, all the time, that reliability is rarely underwritten by regulation. The regulator requires predictability. In the modern world technology advances so rapidly that by the time predictability is established we're onto something new and the cycle begins again. The regulators forever playing catch up do not deserve disdain but they struggle to overcome their inbuilt prejudices. They are to put it simply not very keen on change.