https://www.continental.aero/diesel/engines/cd155.aspx
https://en.wikipedia.org/wiki/Thielert_Centurion
I think these, combined with biofuel based Jet-A are a good solution to this problem, as electric tech is a long ways from having the range needed.
Maybe someone who knows more could chime in why these haven't already completely replaced the ancient air cooled leaded gas motors? My guess is that they're very expensive...
(There's also a company called Austro engines that makes aero diesel engines, AFAIU even based on the same MB car engines Continental/Thielert uses. I think Austro is a subsidiary or spinoff of Diamond, so that's where you see these engines used.)
Those Mercedes engines are found in small cars and delivery vans around the world, and are widely available and pretty cheap. For example, the Centurion 3.0 uses a Mercedes-Benz OM642 which is found in Freightliner/Sprinter vans, Jeeps, and tons of other very common cars. You can buy these engines straight from Mercedes for like $8k.
In this case, the author mentions using an aluminum marine GMC V8, but not which one exactly. This is most likely based on the LS V8s, which are fairly expensive motors, and a pretty ancient design (e.g. pushrods).
Bingo! Yeah, I was wondering the same while reading the article.
> a pretty ancient design (e.g. pushrods)
Does it matter? The engine is significantly derated vs. the original car engine, so max rpm is going to be much lower, thus no problem with valve float.
(As an aside, when aviation engines started going with 4V designs in the 30'ies, it wasn't only about breathing, but better cooling of the valves was an equally big motivation.)
Even the relatively modern SR22 uses a Lycoming engine: https://cirrusaircraft.com/aircraft/sr20/ - https://en.wikipedia.org/wiki/Lycoming_IO-390
It's actually an aviation crises in the making with 1000's of SR-22s.
That is essentially how any new industry works. EV's were too bad/impractical/expensive until Tesla decided to take the risk and put down the capital to make them mainstream. Why can't/doesn't someone do the same for GA?
It’s the doctor segment that is probably way down, or holding steady.
I wanted to be a pilot. I took lessons in the 1990s at a small field, relatively uncrowded, relatively low cost. I stopped due to weather/money.
When I tried again after I finished college where I lived things were more expensive and the airspace was so crowded you would run up costs waiting in line to take off, and the whole thing was much more stressful.
It has to be fun, in a busy enough environment it becomes stressful enough fewer people want to fly.
But that's a $2m aircraft vs a half-million one.
That's how silly it all is, and why it will stay stuck in Experimental.
There's a couple of companies working in this space:
Turbaero: https://turb.aero/ Turbotech: https://www.turbotech-aero.com/
The odds of a random stranger dying from a light aircraft falling on them are trivial, several orders of magnitude less than the odds of their being hit by a car or being killed by inactivity; the pilot is free to refuse to take off, so risk appraisal really is on them; it's time to dump safety bureaucrats into your nearest woodchipper and CHANGE. THE. LAW. if you want ANY interesting activities or skills to survive.
Insert the "who could have done this" meme with the FAA shooting interest in flying and # of pilots.
Can you explain this further?
Some conditions are uniformly disqualifying, for good reasons. But it results in a perverse situation where a regular person can choose to either get mental health care or fly, but not both.
https://www.faa.gov/pilot-mental-fitness
For me it's completely moot. I can't even have someone else fly me anymore--I have an (apparently untreatable) eustachian tube dysfunction.
...which is probably for the best given my bearish position on aviation.
Oh my sweet summer child.
If these things are that bad, those same people shoudn't be driving either. And this is probably true. However, if you applied these same restrictions to driving, people would absolutely go nuts on you.
Note that 'undiagnosed ADHD' holds as much weight as me saying you have bad energies. There are many conditions that masquerade as ADHD to a layperson, including some purely psychological ones (they are no less real, but are very different from a neurodivergent brain and require very different treatment).
If you are otherwise a high functioning adult (can function in society, operate vehicles safely, etc), get your third class medical, which should be no problem. You have to disclose diagnosed conditions. Do a discovery flight and ask for an opinion from the flight instructor. If he thinks you are fit, go start your training and enjoy.
If, one day, you do get diagnosed (with ADHD or some other disqualifying condition) AND require medication, then it's a problem. If you don't need medication (because most if not all ADHD medications are prohibited), don't try to renew your third class medical (because, if you get denied, it's a big problem) and get advice about BasicMed. It has far less requirements; my understanding is, unless there's something strictly prohibited, if a doctor signs you up you are good to go.
You won't be able to fly commercial or faster than 250knots but I suspect you don't care.
Failing all the above, there's light sports aircraft and gliders(no medical requirements, you just need judge yourself to be capable and unlikely to be incapacitated) – although I am not sure you can operate them while taking meds; some professional advice required here.
Disclaimer 2: Obviously the above assumes that whatever you have does not impair you. This is just to get around FAA's antiquated view on mental health while complying with the law. The most important thing is to be safe. If you really can't due to health issues, then don't, even if a doctor says you are fine.
Otherwise, don't give up!
So I just looked it up and saw it's considered a risk, so I couldn't get a pilot's licence.
This is so strange; for example I pay much, MUCH more attention to my driving on the real roads than at least 99% of other drivers. In fact I'm always one step ahead, mentally calculating what other drivers are experiencing and how that might make them react - etc. This just happens automatically.
Weird. I guess people are just different, but still.
We see the same with dinghy sailing. It used to be a big scene with hundreds of ordinary people showing up for regattas. It was killed by windsurfing (at least here in Europe) and just people moving on to other things ,not regulation of any sort.
People have plenty of expensive and time consuming hobbies. All hobbies are at least time-consuming, that's what a hobby is.
All certifications add to the expenses. It's the reason why one can't buy a headset off amazon and have to pay 1k for a used headset. Sure, safety requires certifications but I guess we went overboard. It's also the reason why GA aircraft are expensive to this day, even those build 40 years ago. It's pretty expensive to keep maintaining old tech at low volumes. I'm rooting for Diamond and their car-derived engines (as well as the Experimental aircraft scene).
Note that boats are also notoriously expensive.
There's a very good parallel to your example: gliders. You want to fly cheap (just to fly, not to go places)? Go soaring. Problem is, it's even more location-dependent.
Why is this worse than the 80s?
I know that paragliding and hang gliding exist, but those are a bit out of my comfort (and safety) zone.
https://en.wikipedia.org/wiki/Ikarus_C42
Technically it is a microlight but top speed and handling are much closer to a regular GA craft. I absolutely loved it and if my eyesight was better I'd definitely go for a license.
I suspect hybrids will be developed first. Basically an APU sending power to the main motor + a relatively small battery. The 'APU' can be relatively compact and deliver a lot of power, with less engineering requirements (can place it anywhere, doesn't need to interface with a prop). If it fails you have some emergency battery power. Electric motors are incredibly strong and have very few moving parts, so reliability is higher. They are also light.
Net net, there's some complexity and the combined equipment may be heavier (may! existing powerplants are some heavy beasts) but there's probably advantages.
Certification would be horrendous, I imagine.
In my vision a compact rotary (that inside-out rotary patent a few years ago looked even more promising) would recharge the battery subsystem. Or maybe a fuel cell.
The same would probably work for GA. Really, hybrids will work regardless of the battery tech for the next couple decades.
Hybrid planes would be quite attractive, but of course the certification bareer which might be too large
So you effectively electrify 5x the number of cars...
But, that opportunity has passed, at least we are moving towards electrification.
If I recall correctly, Cessna was found infinitely liable for every plane manufactured, meaning that each new plane off the assembly line increased their potential overall liability without liability over decades-old planes expiring and decreasing it.
This was a problem in the 90s. And it was fixed! Back when the government still fixed things. https://en.wikipedia.org/wiki/General_Aviation_Revitalizatio...
Car engines today are much more efficient than they were 50-70 years ago, but that's because the difference between maximum power and cruise power for a car ranges from about 5x to 20x. Much of the efficiency gains come from devising ways to deliver short bursts of power from a small engine, such as variable valve lift and turbocharging.
General aviation aircraft cruise at about 75% power. There's much less to be gained by optimizing the engine to run efficiently at 10%, and running a small engine at high RPM and high boost continuously is a recipe for frequent service intervals.
That's ignoring improvements to transmissions, tires, and aerodynamics in cars that aren't relevant to planes. There's certainly room for improvement, but not to the dramatic degree we've seen with cars.
True, the BSFC numbers of these old school aero engines aren't that bad, actually.
> General aviation aircraft cruise at about 75% power. There's much less to be gained by optimizing the engine to run efficiently at 10%
I think the real advantage isn't a small efficiency gain in optimal conditions, but rather that with a modern FADEC there's less pilot workload, with a single lever for selecting the thrust the pilot wants, and the electronics takes care of selecting the optimal parameters (amount of fuel, ignition timing etc.) for that thrust setting, taking into account input from a number of sensors (temperatures, pressure, etc.). And all those sensors provide data that can be logged and help with planning maintenance before something goes pear-shaped up in the air.
> running a small engine at high RPM and high boost continuously is a recipe for frequent service intervals.
The Rotax aero engines rev to a max of almost 6000 rpm, cruise is ~5000 rpm, and they have a normal(?) TBO of 2000 hours, including the turbocharged 914. (The turbocharged 915iS has a TBO of 1200 hours, but I suspect it's due to the engine being relatively new, probably the interval will be extended when more experience has been gained?). Of course, these engines are designed for that from the ground up, not saying you could take a random car engine off the street and run it at 5000 rpm for 2000 hours.