I'm surprised the article doesn't mention the Cessna 182, which also started production in 1956 and is still rolling out of the factory new today.
While the article extols the virtue of the 172's engine, the fact is that the vast majority of them are running very old designs with carburetors and on Avgas. Avgas still contains lead. These old engines are hugely inefficient and flown incorrectly prone to cracked cylinders. Newer models are fuel injected and there are also a few diesel conversions.
All Cessna single engine aircraft now have to undergo supplementary inspections (SIDS), at least in Australia and I think it is the same in the US. I've seen first hand the horrendous amount of corrosion which can hide in a 50 year old aeroplane and not be found until the wings are removed. These SIDS inspections have the potential to ground much of the older 152/172/182 fleet and render what was a $25,000 asset practically worthless. It will be uneconomical to repair in many cases.
The above has happened to me personally with a Cessna 182. In the end it was sold for scrap with only the engine and avionics retaining any value. I've also seen the costs of these inspections on a Cessna 210 exceed $20,000. It needed a whole new main wing spar amongst other things.
The point I am making is that these very old single engine light aircraft need very meticulous inspections now to ensure they are still safe to fly. I do believe there are probably quite a few seriously at risk aeroplanes still flying today, especially if they have been left outside in coastal areas for any length of time.
I used to own a light aeroplane maintenance business.
Agreed. I got my PP license 40 years ago on a 172, then 4 years ago went thru training again to renew but quit due to the condition of the planes (all 150's, 172's). I also quit because I realised (maybe because I'm older now), that there is no place for a part-time pilot. Too dangerous. Either you fly every day or don't fly at all because eventually something is going to happen, especially considering the planes I was flying and if you fly 1-2 times a month you are ill-equipped to handle any emergency situation.
I did a bit of training in a Cessna 152 but one day we had to take a 172 it was like going from a Yugo to a Cadillac.
In the 152 I was literally rubbing shoulders with my instructor but in the 172 we had shoulder room. The 172 has four seats and feels huge compared to the 152, well really it is huge compared to the 152.
I have my baptism flight a month ago in a 152. The instructor was worried because he couldn't fully move the wheel back because of my knees, then I tried another position and he couldn't press the pedals. It took us a while to find a position for my legs, but I didn't feel safe about this until we landed.
I am tall 1.90m (6'3"). I want to take classes further but I think I should find another plane.
Note: I used a Fiat 600 for like 6 months. I think the 152 is smaller inside.
I have 200 hours in a 150 and I'm your height. You'll get used to it. Keep in mind that the 150/2 is a better training plane than the 172. It will teach you to respect the rudder and the crosswinds, while a 172 is forgiving to the point that it may become dangerous. Also, anxiety is normal initially. I'm saying that because there's a difference of ... 1/4" between the two planes' cabin width (39 1/2 to 39 1/4).
Last time I was in the air in a private plane was a 152 a couple of months after a friend achieved his pilot's license. We're both 6'2" and around 190lbs. It took a bit of work, and we were shoulder to shoulder the entire flight, but it was workable. The cabin of the 152 is smaller than any car I've ever been inside of. There's room behind the seats for maybe two backpacks.
>I've seen first hand the horrendous amount of corrosion which can hide in a 50 year old aeroplane and not be found until the wings are removed.
If it's such a problem, how come there hasn't been a single case of a in-flight structural failure from corrosion of any strut-braced Cessna? In fact there have only been two cases of structural failure in 172s, both of which appear to have been caused by trying to do aerobatics:
It could be that the SIDS inspections are in place to prevent catastrophic structural failures.
One single edition of Flight Safety Australia in 2015 lists five reports of corrosion in Cessna singles, including specifically relating to the main wing spar.
Just to note: SIDS are not required for part 91 operations, at least in the US. If your aircraft is part of a Cessna maintenance program, then it will get lumped in, but for many older aircraft who are privately owned and flown, SIDS are recommended but not required by the FAA..at least not yet.
That has to be one of the most interesting career paths that I'm aware of. Impressed with your ability to adapt and learn outside of some narrow envelope.
I've also worked at a major dotcom, starting pre-2000 for all the fun, and in the television industry for a major UK broadcaster.
While each industry has required its own knowledge, I have more or less been applying the same set of skills. For example, now in the pharma engineering R&D role, I'm just a project manager rather than a scientist. I read a handful of in-depth papers in my specific area (Optical Coherence Tomography) and by then I could at least understand the technology. I also had just moved to a new country, needed a job and they needed someone with good English and reasonable management skills.
The horses and data science interests are linked and the direction where I want things to seriously go next. I'm learning the trade and just starting out now.
Or, you could look at my career path and deduce that I just get bored easily....
I've never really thought about it as inspiring, because it's just been "life." I try to do things I'm interested in and then when circumstances change, I look for something else.
I have a friend who was a tour guide and fitness trainer for many years. He's climbed Kilimanjaro something like 12 times. Now, in his early 40s, he is well on the way to obtaining his commercial pilot's licence. It's something he's wanted to do since a teenager and has saved towards that target for a long time. To me, that kind of dedication is inspiring.
This would now probably get into the big debate around running these engines rich of peak or lean of peak.
Generally, speaking engines of this type are manually leaned - full rich for take off, climb and landing, then leaned for fuel conservation in cruise. The debate is around whether it is better for the engine to be run slightly richer or slightly leaner over an extended period of time. Slightly lean of peak is probably better.
However, if leaned too much there is the risk of one or more cylinders overheating. Exhaust Gas Temperature (EGT) guages should be used to monitor this. Many older Cessna 172/182s wouldn't be fitted with EGTs. They certainly weren't factory standard in the 50s, 60s and 70s.
All this leaning of mixture is done manually, by turning a knob screw in the cockpit.
Another risk is shock cooling. This isn't really an issue with Cessna singles, but can be a real problem with heavier twins like a Piper Chieftain (PA31-350). They easentially run two bigger versions of a very similar engine.
When lean of peak, leaner is cooler, so the overheating risk you're describing is generally from cylinders operated "not lean enough" if the intent was to operate lean of peak.
But, in general, leaner is hotter, not cooler. At a ROP setting, the extra fuel that is not burned lands on many of the top end components including the exhaust valve. As it evaporates off the surface or out of the fuel/air charge, it cools the component or charge.
Also, peak cylinder pressures are higher when run RoP.
or the CHT line on the graph in Lycoming's (in)famous "Experts are Everywhere" document: http://users.kymp.net/kotkanik/documents/SSP700A.pdf (note that in the Lycoming document, leaner mixtures are on the left and in the APS red box graph, leaner mixtures are on the right; Lycoming graphs BSFC and APS graphs 1/BSFC)
> But, in general, leaner is hotter, not cooler.
That is not borne out by the data shown in graphical form in the links above (which agree with each other and match my experience operating big-bore Continental engines).
Only while richer than 25 rich of peak EGT is your statement correct. Lean of peak, leaner is in fact cooler, which was my original claim.
> Also, peak cylinder pressures are higher when run RoP.
From a cylinder longevity standpoint, this is a bad thing, of course. It's particularly a bad thing when cylinders are run very hot (over say 425F) because aluminum loses a significant percentage of its strength in that temperature regime: https://www.nap.edu/openbook/NX006900/xhtml/images/p20003245...
Also keep in mind that these are air-cooled engines. Due to the configuration, it may very well be the case that one or both rear cylinders are not receiving the same cooling effect as the front two. Therefore, even if you're running lean of peak, it's very, very important not to overdo it
On a Cessna 182 I used to run, I could lean it to 50-52 litres per hour, using a digital fuel flow gauge (not standard factory equipment). If I leaned to 48 litres per hour, the EGT gauges clearly showed a rise in temperature for certain cylinders.
If I was leaning without using these gauges for assistance, it would be very easy to make a mistake and overdo it, or not lean enough and waste fuel/money.
Yes. Good old fashioned corporate snark. Even though I disagree with Lycoming's estimation of how difficult it is to operate lean of peak and agree with the APS/GAMI "experts", I do appreciate that Lycoming came out swinging and published the snark.
I would recommend an all-cylinder CHT and EGT graphic engine monitor (ideally with data recording, as that makes some aspects of engine management easier).
Keep the CHTs under 380F in cruise and under 400F in climb (380F is better, but not all planes can do that at heavier weights).
Shouldn't the leaded fuel make the engine less prone to detonation and cylinder cracking? Also how do you tune carburetors on an airplane? Do you target the cruising altitude of the aircraft or above that altitude maybe?
Yes, the lead raises the effective octane, preventing detonation. The other tool for preventing detonation is running extremely rich fuel/air ratios, the typical setup for the airplane at full takeoff power.
You target an appropriately rich mixture at sea level when tuning the carb or adjusting fuel flow for injected engines. The pilot manually leans the mixture as the aircraft climbs to maintain a reasonable fuel/air ratio.
Owners sometimes call that mixture lever the money lever because it governs fuel flow, aka "dollars spent per minute".
Hjelmco is certainly fighting the good fight in that regard.
Which brings up the point of the availability of Avgas worldwide.
I had an aeroplane ferried from the UK to Australia, via the middle east and asia. Avgas, with engines only certified to use the leaded variety, was extremely hard to find and extremely expensive through much of the region. I have a photo of the aircraft being refuelled in India via hand held funnel and two gallon cans.
This also means that many of the NGO and small relief aircraft which used to be active in those areas are no more.
Still plenty of JetA1 available, but one needs a totally different engine for that.....
Last time I looked, few years ago it seemed the long term solution was to switch to diesel. Diesel has some advantages, higher efficiency means lower fuel consumption, energy per gallon is higher, but lower per pound. And also diesel is safer to handle.
Probably modern materials allow for reliable diesel aircraft engines that are lower cost over the life of the aircraft. But difficult though since the pace of development in the light aircraft industry is very slow and there is little money in it.
I wonder why there's no effort to make affordable turboprop engines in the power range required for typical GA usage. Sure, small turbines take an efficiency hit (boundary layer friction and whatnot), but still? And what makes them so expensive compared to piston engines?
But yeah, maybe small diesel engines are a better approach, shrug... And some of the designs look neat, e.g. opposed piston two-stroke like ye olde Junkers engines.
There's also efforts to create and certify an unleaded replacement for 100LL. Probably won't solve the price and availability issues with avgas, but at least it doesn't contain lead (which in addition to the environmental issues is a PITA for refineries ) and I guess it's a hedge against that last TEL-producing factory on the planet going bankrupt and grounding the fleet..
Hybrid Electric aircraft are kinda interesting when you start running the numbers.
The weight of the batteries of course reduces the amount of fuel the aircraft can carry. However increased efficiency reduces the amount of fuel you need to carry. There are a bunch of other advantages which would improve safety.
In particular better throttle response. A problem with turbine engines is when an aircraft is hit by wind shear during landing you need more power right now, and turbines have lag. And also when you shutdown an engine in a multi-engine aircraft you have a serious thrust imbalance. Hybrid electric would allow power to be routed evenly to each fan
as needed.
Traditionally you deal with the lag with variable pitch propellers. But with electric motors you can have a lot of immediate / momentary torque and power and instead vary the propeller speed.
I think what is aimed at with electrics is you get a lot simpler aircraft with far lower operating costs and higher reliability and availability.
No engine maintenance, no variable pitch propeller, no fuel systems (you do have batteries but they should be self contained man changeable systems). No huge checklists with warmup etc procedures on the ground.
It's worth it to just have 30-60 minutes of flight time, because you still get to train takeoffs and landings.
Maybe the instructor and student can first swap the new battery with 5x20 kg units or so, take off, do a few touch and go:s, land, then let the next guys do the same.
I think most everyone that tried introducing diesel aero engines in the early 2000's went bankrupt. Which actually isn't the end of things as long as the business is sound.
The QUEST Kodiak is filling in for many of the larger NGOs. I believe it was designed for that express purpose (taking over where the small avgas powered planes could no longer operate due to the price or availability of avgas).
Unfortunately Turboprops come with a whole new set of maintenance requirements but otherwise it's an excellent aircraft and working out quite well.
I think the Quest Kodiak is a great aeroplane, and very comparable to the Cessna 208. Both have many advantages over the Cessna 206s and 210s which were fulfilling these types of roles over the previous 40 years.
The biggest issues with both of these is the cost to buy and also the cost to maintain. Both are well in excess of the older Cessnas.
Not sure which comment you're replying to, but if it's my original post about hidden corrosion, then yes it will apply to all older light aviation types.
However, some are potentially more vulnerable than others. A high wing Cessna 172, parked uncovered outside in a coastal area is going to be much worse in many aspects than a low wing Piper Archer, hangared somewhere inland.
Here's an FAQ from the Australian regulator. It states that they are in discussion with Beechcraft and Piper regarding SIDS:
I have flown one, and while good, it is not "that good". What happened is the FAA rules are so stringent to create a new aircraft, that the subsequent cost was so high, that few new small plane designs make ROI sense. This has created a case where the strict rules in the name of safety have actually caused a reduction in safety. This plane was originally designed on slide rules. Today we could create more optimized designs in almost every metric, including safety, but no company can afford to do so. The FAA is supposed to change these rules soon.
The Tecnam P2010 (designed in 2010, FAR 23 certified in 2015) is the most recent single engine, 4 seat, high wing airplane to be certified by the FAA. The second most recent is the Cessna 177. That was certified in 1968.
That's just because new material technology makes high wing aircraft not very useful anymore. Plenty of low-wings get certified by the FAA (the cirruses, diamonds...)
I like to think Eclipse had a shot, but they blew up in 2008. The housing boom might have been the only reason they existed, but the housing bust absolutely killed them.
Having to throw away that first engine design could have been survivable if the economy didn't get so sucky so fast.
Cirrus just certified the SF-50 Vision, a new single-engine VLJ.
Cessna doesn't call it this, but the Mustang is pretty close to VLJ sizes. (Not many being made though, as their M2 pretty much took over that space of the market.) The Embraer Phenom 100 is similar. Both have been reasonably successful.
The problem is total sales are going to be tiny. You might sell 2,000 aircraft per year with an amazing design, but that's just not much to justify a lot of R&D. So yes the FAA could make it a little cheaper, but don't expect that to change much.
In 2016, a grand total of 2262 general aviation aircraft was shipped (haha) worldwide, of which 890 single engine piston (as the Cessna 172 of the article).
Thus, if you go into the single engine piston market and grab a full 10% of it, you'll be selling fewer than 100 aircraft a year.
What I don't understand is the number of companies that started building LSAs. It was a great idea and has lowered the costs, but there are so many of them I don't see how anyone can make enough money to bring prices down.
They're different segments of the market though. A new 172 is closer to a new SR20 than it is to an old 172.
If you want a reasonably priced plane to go buzz around on the weekend, you get a 172 from the 60s-70s for $25k-$60k. If you've got $300k+ to spend on a plane and wanna get the latest and greatest, then you start looking at new 172s or an SR20 or something.
Planes don't really die unless they get crashed, are seriously neglected, or an AD comes out with prohibitively high costs to get in compliance (e.g. L-13 Blanik). Almost all those old planes are still around, so there isn't much reason to be buying new ones. It's a testament to the success of the 172 that 50 years later, nobody is buying new basic trainers and the only way to sell new aircraft is to offer the latest and greatest tech.
I'm not sure the Cirruses would make very good trainers. If nothing else, I think you'd want something where the spin recovery procedure is something better than "pull the big red handle and call your insurance company."
Haha, yeah, though to be fair I think we should build that particular handle on everything and train it appropriately, while still training spin recovery. Airframe parachutes are a great idea.
I love the idea of the parachute. But it seems like the sort of thing that ought to be a backup if you can't recover, not the one and only thing you do.
I'm not a flight instructor, but I have to imagine that inadvertent spin entry is something student pilots might do from time to time, in something that can spin. (I did all of my initial training in craft that refused to spin with my weight in them, so it's a bit theoretical for me. I did get spin training later on in something that would actually spin, and I'm glad I did.)
I completely agree with your last-resort comment, but the discussion has made me curious about Cirrus' spin-entry and spin-recovery behavior. After an admittedly cursory search, I get the impression that in neither case do they behave badly. The problem here is that the Cirrus' spin certification is predicated on the parachute being the only method of recovery. The article below offers several justifications for not getting the aircraft certified on the basis of standard recovery procedures, which seem to boil down to the principle that the rule 'pop the chute as soon as you are in trouble' is most likely to reduce fatalities. From the point of view of pilot training school economics, the cost of a certain number of write-offs must be balanced against a smaller, but non-zero, probability of fatal spin accidents (beyond the number that not even a parachute would save.)
Yeah; that was a CF all around. Pilot under some stress, air traffic control making it increasingly (and unnecessarily, IMO) worse. https://www.youtube.com/watch?v=HEVLqRIqd84
Pilot in command ultimately responsible, but damn, ATC did her no favors that day.
There's only one certificate in the FAA line up that requires actually spinning an aircraft. In that sense the Cirrus makes a perfectly acceptable trainer.
I'm not thinking of deliberate spins, but rather that it seems like students might spin by accident from time to time, and it would be good if that didn't automatically total the aircraft.
I've obviously never attempted to intentionally spin a Cirrus but in my experience and in talking with many other instructors in the aircraft it's nearly impossible to get the aircraft to enter a spin. The stall characteristics of the split chord wing make it difficult to even fully stall the aircraft.
All slow flight training must be done at a safe altitude. The emphasis on slow flight is familiarity with aircraft handling near stall speed, intentionally stalling it so you can practice proper recovery. There is already a failure if you stall, and then there's a second failure if you don't immediately recover. A stall spin at low altitude requires three failures: stall, stalling at low altitude, improper recovery which then leads to entering the spin (one wing with more developed stall condition than the other).
Right, but with a Cirrus, a stall with an improper recovery that leads to a spin results in a totaled aircraft even at high altitude. The big red handle will save the lives of those onboard, but the insurance company buys the plane as soon as you pull it.
I've been in the market for a plane for a while and have yet to fly a da40. What about them so you find better than a 182? They seem more economical in terms of fuel.
It's just a nice pilot's plane, i.e. for flying, not transportation. It combines some advantages of the Cessna (e.g. benign handling, safety) and the Cirrus (e.g. modern, faster than the Cessna tractor). I've never owned one, so can't talk bout maintenance etc. though.
Phil Greenspan has a nice review (though a decade old):
Faster, far more intelligently designed with better ergonomics and UX, can glide forever on a dead engine. The problem is two words: useful load. Good luck putting four adults with bags in a DA40
Can't do that in Cessna 172 either. But yeah, Cessna 182 probably.
There are models with higher useful load, definitely something to look out for, but basically it's a two-seater, or three without luggage, just like the Cessna 172.
That's right, and that's probably one of the reasons the DA40 is typically seen to compete with the 172 more than the 182.
If you need 4pax+ load, Diamond doesn't really have anything, unless you upgrade to a twin. The DA50 was supposed to fill that gap in the matrix, I guess.
I wouldn't call either of those trainers. Don't get me wrong, owning a 172 is fine and I'd love to own one. I just wouldn't buy it and say "boy, I've got a fancy, sporty airplane here," even if you stick a G1000 in it like those Cirrus models.
It's a workhorse, like a pickup. Cirrus aircraft are a lot sportier. (You are correct, though, the SR22 sells like hotcakes. I think it's #1.)
If you look at the history of most small aircaft you can find military involvement at the beginning, usually wanting an aircraft for training or spotting.
Militaries with big budgets don't have much reason to buy small fixed-wing piston aircraft anymore, or at least they lack the incentive to invest in new clean-slate designs. And if you don't have that startup customer willing to make a big purchase and maybe even fund R&D it becomes impossible to justify a new type.
Quite different, the turboprop for the Super Tucano is the better chunk of $1 million. It's a Lamborghini in the propeller plane world, where the 172 is a Honda Civic.
the staleness of the situation naturally leads to a kind of Uber style dialectic resolution when technology unleashes the forces which just can't fit into the stale/outdated rules and that is definitely going to happen once cheap electric VTOL multicopters capable of lifting 1-2 persons appear (yes, my education was in USSR, so Uber is a typical case from Hegel/Marx in my worldview :)
Battery battery battery! So far, flight times don't exceed 20 minutes or so... :-/
But yes, can't wait for battery tech to improve. It'll be great both for multicopters, and for good old fixed wing with an electric engine (you'd achieve longer range and endurance than in multicopters for given crap battery tech).
>Battery battery battery! So far, flight times don't exceed 20 minutes or so... :-/
drop half the battery and replace with ICE based generator, and you'll have best of both worlds - endurance of ICE with controllability, safety, convenience and other advantages of electric engine multicopter. That can already happen today, just somebody should go to garage and make it happen (i myself live in a condo without such a garage unfortunately. Btw, SV innovations were done in garages and with all those condos rising around without such garages i wonder how we're going to do it here in future:) In several years the metall-air fuel cells are going to appear which is even better - size/weight comparable to ICE with efficiency close to battery based electric.
Ah, so just like off-the-shelf RC planes at the moment, then :)
Batteries are heavy. Gasoline has tons of energy for how much it weighs. New battery tech shows up on HN all the time and I've never seen one come to market. LIFePO4 and other similar lithium chemistries are still state-of-the-art in terms of what you can buy right now.
"Indeed, the theoretical specific energy of a non-aqueous Li-air battery (in the charged state with Li2O2 product and excluding the oxygen mass) is ~12 kWh/kg. This is comparable with the theoretical specific energy of gasoline (~13 kWh/kg). In practice, the Li-air batteries with a specific energy of ~1.7 kWh/kg at the cell level have been developed."
"However, the areal power and cycle life of lithium–oxygen–air batteries need significant improvements before they can find any competitive market niche."
So, they're still an order of magnitude away from gasoline and you can't buy one today (or probably in 20 years either).
To be fair, electric engines are much more efficient than internal combustion engines, so you don't need to achieve the same specific energy to achieve comparable outcomes.
But, to be realistic, one of the startup "stars" of the battery scene, Envia, is marketing an aviation battery with 0.35 kWh/kg, so I'd say that's realistic state of the art. So, even getting the 1.7 kWh/kg you mentioned in a production-ready battery would be huge.
There is also something that the OP didn't mention in the market of kit planes/experimental class. If you are already trying to cut cost on a buyer level a kit plane can often make more sense then buying something already built. The used market is very strong too, similar to boating, where planes can have a very long active and useful life.
The article mentions the longest non-stop flight briefly - that was quite a story: the two guys flew for 2 months non-stop.
Here [1] are some pictures, incl. of the refuelling. Below some tidbits I found interesting or amusing:
- after take-off, they did a low pass to let a chase car paint white stripes on the tires, so that they could not cheat undetected (by landing somewhere and taking a break).
- they refuelled about twice a day
> “I once asked John’s widow if they handed down the waste during refueling runs. She said, ‘No. That’s why it’s so green around Blythe.’ ”
> Some time after the flight, Cook was asked by a reporter if he would ever try to replicate the stunt, to which he replied: “Next time I feel in the mood to fly endurance, I’m going to lock myself in a garbage can with the vacuum cleaner running, and have Bob serve me T-bone steaks chopped up in a thermos bottle. That is, until my psychiatrist opens for business in the morning.”
They are still producing them because it's cheap due to "grandfathering" laws.
"grandfathering" means if you'd design an airplane like 172 today they wouldn't meet the safety standards and you wouldn't be able to produce them, but since they were designed back in the days, if they don't change the design, they can still produce them.
I fly 172 regularly. It's a safe plane, but you have to know quite a bit about engine and how it works to be really safe up in the sky. I had engine failure on take-off with extremely well maintained plane. Starting the engine is a pain in the ass for most civilians who don't understand 4 stroke engines.
Cessna 172 uses about 10 gallons of fuel per hour. That's quite a lot. I think in 2017 there's better options out there.
I had a partial engine failure in a fairly new fuel injected Cessna 172 during descent to landing... didn't overfly the airfield to check wind, but landed instead.
The article states:
> Luckily, the Cessna’s engine is about as reliable as aircraft engines gets.
Unfortunately, that's not that reliable. Statistics I've read (can't locate them now unfortunately) indicate about 2 to 10 inflight engine problems per 100,000 hours, which doesn't sound a lot. But if you fly two hours a weekend, making 1000 hours over a decade, that's a 2 to 10% chance of encountering engine problems right there.
Fixed spark timing is not that big an engineering deficit for an engine that runs at a fairly constant power setting.
Road-going cars need variable spark timing because they are called upon to efficiently make wildly varying amounts of power. (Idle, cruise, accelerate are all part of the normal drive cycle.) Airplane engines, many racecars, and other similar applications that need to produce fixed, high power for prolonged periods of time often use fixed timing mechanisms.
In the last 60 years, automobile engines have improved many times: for instance, the 4.4 liter 8 cylinder engine powering the 1954 Pontiac Chieftain[1] produced as much horsepower and torque as the 1.4 liter turbo in my 2013 Chevy Sonic[2] - and it's not even a particularly good or modern engine. (Disclaimer: I work for GM, I'm using these models because I'm familiar with them)
Has the engine in the 172 been improved in that time period? The article says it has not, but I can't imagine using 60 year old tech like that.
I understand that it is "proven" tech, but that would be like saying that punch-cards are "proven" tech nowadays.
> Has the engine in the 172 been improved in that time period? The article says it has not, but I can't imagine using 60 year old tech like that.
It's not the exact same engine, but it's the same technology - an air cooled 360 cubic inch horizontally opposed 4 cylinder engine. Magnetos provide spark, and as far as I'm aware the fuel injection is mechanical.
"Modern" piston engines used in aviation are essentially 1950's technology. They're surprisingly reliable for what they are, but innovation isn't really happening in the piston world.
There was an interesting upgrade being worked on by a couple of guys in Florida. It turns out that the engines in these planes have an expected lifespan of 2,000 hours or so, and can't use gas with ethanol in it, and replacement engines can cost in excess of $20,000; these guys worked on a way to drop in a $5,000 Chevy Corvette engine and greatly increase fuel economy, reduce noise, reduce vibration, and supposedly increase reliability. When they asked the FAA to sign off on it as a replacement they were told that without redundant spark plugs/spark sources it wouldn't be approved. This makes sense when magnetos are expected to be rebuilt every 500 hours, but it killed the Corvette engine replacement idea.
Regulation slows innovation. General Aviation proves it IMO.
Dual plug heads, and dual distributor setups are available off the shelf for LSx engines in drag race applications. One wonders why they didn't do the conversion. Although new heads and twin dizzys would easily double the cost, that much reliable power in the aero world would still be a good deal for many.
FWIW, I once had a faulty spark plug in one cylinder in a Cessna 172 in Ondangwa, Namibia (and no, "burning it off" by running the engine lean on full throttle didn't fix it). So, I flew back to maintenance in Windhoek on the other spark plug, using IFR ("I follow roads") in case the other gave up (which it didn't).
So are you allowed to this to your own personal plane (engine swap with non standard engine)? Or do you still have to get FAA approval even for private use?
I guess I'm wondering if there's a grassroots community of people doing engine swaps on their planes?
For a type-certified airplane (roughly "one built in a factory"), such an engine swap would require a Supplemental Type Certificate (STC). The process of creating such an STC would require a fairly extensive engineering study as well as flight-testing to prove the new engine was suitable in all regards. During that time period of developing the STC, you would place the aircraft into "Experimental" category to do the testing.
While possible, economically "it's not going to happen".
For non-type-certificated airplanes, there is a large grassroots community around "Experimental-Amateur Built" (E-AB) aircraft. EAA (www.eaa.org) is the largest owner club; they put on "Oshkosh" every year, which is the world's largest fly-in (of E-AB and factory aircraft). In E-AB, the constructor of the airplane has nearly full latitude to choose their engine setup (and to change it later). My limited experience suggests that those who start with tried-and-true aviation-origin engines have a higher success rate with their projects.
And that is the problem. These old Avgas burning carburetored dinosaurs are hugely inefficient. However, the effort required to certify new engine designs for light aviation is prohibitive, because they're never going to sell in numbers high enough to recoup the development/certification costs.
Diamond Aircraft in Austria are producing single and twin engine light aeroplanes with diesel engines, oriignally based on an automotive design. However, they've been through a bankruptcy event and are frankly lucky to still be manufacturing.
There are options to retro-fit diesel engines to the single Cessna range, but if I recall correctly, a deal for a new factory build with that option fell through a couple of years ago. Buy a new Cessna 182, still fill it with Avgas.
Aircraft piston engine efficiency is actually quite similar (measured in brake specific fuel consumption) to modern auto engines. The Lycoming O-320 in a Cessna 172 burns 280 g/kWh. Modern auto engines like the EcoBoost burn not much less -- ~250 g/kWh. See https://en.wikipedia.org/wiki/Brake_specific_fuel_consumptio....
Moreover, aircraft engines like the O-320 can run for hours at continuous max power output. Good luck doing that with a car engine.
Car engines absolutely demolish aircraft engines on emissions, though. They have O2 sensors, computer-controlled ignition systems, and catalytic converters, whereas aircraft piston engines have fixed ignition timing and burn extremely rich of peak (meaning massive emissions) at takeoff power. And on top of that, while little engines like the O-320 can burn ethanol-free autogas, the big piston engines like a Continental IO-550 require leaded fuel, adding another pollutant to the mix.
The diesel engines that Diamond sells now (from Austro Engine) are unrelated to the the old troubled Thielert diesel engines they initially used, IIRC.
No, it hasn't. Or, there's been aftermarket options and multiple attempts to make more efficient engines, but many have had reliability problems.
When your life depends on it, you're more likely to choose the engine that has all of the kinks worked out, has proven reliability, and where the failure modes are pretty well known.
* the avionics have improved immensely (solid state gyro instead of vacuum-pump driven mechanical gyro, for example, GPS, etc.)
* in tandem with that, cockpits have improved ("glass cockpit" with two or more huge screens instead of the traditional 6-pack of small instruments)
* there's been innovation and progress in materials (composite instead of aluminium)
But the engines are still the old dinosaurs from the 60s :-(
That's one reason many pilots are watching battery tech and electric engines with interest (so far, the specific energy of batteries is way too low, giving an hour of endurance if you're lucky).
This might be Stockholm syndrome, but I'm fairly happy with the 1960s-tech TNIO-550B (turbo-normalized, fuel-injected 550 cubic inch 6 cylinder opposed [boxer] engine) that powers my A36. The only significant downside is that it requires 100 octane fuel and the only certified option in the US right now contains tetraethyl lead(TEL).
There are several companies making unleaded fuel undergoing certification testing right now. It's not clear which one (if any) will "win", but I have high hopes that one of them will.
In terms of efficiency, that airplane does >200mph at better than 15mpg. That's not too bad, IMO. Better engine management tech would get me an easier workload as a pilot, but I don't expect it would yield meaningfully more power or efficiency, unless you were to raise the compression ratio (which typically requires higher octane fuel, and existing 100LL fuel is already pushing it, with a rich detonation performance of roughly 130 octane due to the benefits of TEL)
While it's "only" 52 years old, another plane still in production (albeit under a new company) that's worthy of discussion is the de Havilland Canada (now Viking) DHC-6 Twin Otter[1].
The Twin Otter isn't just nice to fly, cheap, or ubiquitous. It isn't just a mainstay bush plane everywhere. It's still the best plane in existence for certain extreme requirements.
Many different planes can go deep into Antarctica during the summer, but when somebody gets sick enough to warrant evacuation from Amundsen-Scott South Pole Station in Antarctica in the middle of winter, as happened in 2016[2], the DHC-6 is still the best plane for the job. In fact, two DHC-6's went because the only plane capable of performing search and rescue for the first was another DHC-6. There simply aren't other planes out there that can land on a short, frozen runway in the dark of an Antarctic Winter when temperatures are so cold that fuel turns into jelly[3].
Viking has been modernizing many aspects of the Twin Otter, but they're still making Twin Otters. The Twin Otter is 52 years old and still does things no other plane can.
I think this article is a little miss leading. I did most of my initial flight training in a 172 I bought with a friend. We had it parked in Tucson near a company that was building custom planes and blazing the trail in glass cockpit design. After a couple years I had built friendships with a number of people there and built the following picture of the industry:
Innovation in private aviation is so small that it's dead, this isn't because someone owns the market but because FAA certification of new technologies is a 15 year not like 20 to 25 year process.
Why? You ask?
Starting in the 70s and into the early 80s there were a number of high profile crashes of private planes. Think Woz, a number of these crashes were due to pilot error, but a number of them became civil lawsuits where the operational complexity of the aircraft was blamed. The FAA was called upon to develope stricter standards which put many private aviation companies out of business. Cessna survived but based on the high price of getting new tech certified which lowers competition there is a way lower incentive for them to change the design.
Many of the parts in the engine of my 172 were OE ford parts found on cars in the 60s but the FAA certified stamp meant we would have to buy the 300 dollar version.
TL;DR: the enduring success of the Cessna 150-180 is actually a tradgedy of blocked innovation and not something to be proud of.
> Many of the parts in the engine of my 172 were OE ford parts found on cars in the 60s but the FAA certified stamp meant we would have to buy the 300 dollar version.
Here's an interesting tidbit. The voltage regulator for the 14V 172 and 182 was literally made on a parts line that also supplied Ford. For quality control reasons, Ford required statistical inspection of voltage regulators destined for Ford. Cessna required 100% inspection. Because they were made on the same line, a set number got the inspection, some of the inspected parts got Cessna part numbers and FAA PMA stamps, and as a result, Ford was also assured their voltage regulators were OK even though a smaller percentage of those eventually sold by Ford were inspected.
I have heard similar stories, I have also often heard the rumor that its really important to check out the ford parts in the engine of any Cessna you are looking at buying because some mechanics will sneak in the vehicle OE parts when working on their own restoration projects. Which can then get expensive the next time you do 100 hour inspection with an above board mechanic.
There are a lot of 1950s and 1960s aircraft designs still flying. That was when smart people went into aircraft design, and it was the most productive period in aircraft design history, as everything went jet-powered. The B-52, the B-737, the B-747, the SR-71, and the Concorde are all from that period. (So are a lot of duds, of interest only to aviation historians.)
Ben Rich, former head of the Lockheed Skunk Works, once remarked that he'd worked on 30-some aircraft in his career, but today's engineer will be lucky to work on one.
I worked on six aircraft by my mid-20s, if you count internships. I'm 31 now. Rich was more referring to sprawling military programs with legislative delays. You can change programs within a company, or change companies.
Also, you're kidding yourself if you think any a/c from the '50s is flying with all original parts. Like any machine, it can run indefinitely as long as you replace components. At my first company out of college, we were updating aircraft put into service in the '60s. We did new engineering to redesign parts, for example replacing an assembly of three primary components with a single CNC machined piece of aluminum. It just was not possible to fabricate the geometry with tools of that era. The new assy was simpler and stronger. Advances and upkeep like these are what keep old machines flying.
Not only would it be highly improbable, it would be highly illegal. The FAA mandates inspections and part replacements/engine rebuilds at certain hour intervals.
Engine manufacturers typically specify a TBO -- Time Before Overhaul, which is the number of hours in service an engine can run before it needs to be torn down, inspected, and overhauled according to the manufacturer's procedure.
For the most part, commercial operators must adhere to these recommended times, but aircraft operated under FAR Part 91 (roughly, those that aren't used for commercial transportation) aren't required to follow the TBO recommendation. You can run it as long as you want.
In practice, most operators do follow those guidelines. I've never heard of any engine doing much more than 2x the TBO before requiring major overhaul. And you'll often need various repairs to cylinders and engine accessories along the way.
Interestingly, manufacturers also specify calendar time limits on TBO, but private operators commonly ignore these. Lots of airplanes only fly 25 hours or so a year.
In the mid 60's and mid 70's, US manufactures were selling over 10,000 single engine piston aircraft a year. Last year, it was 685 single engine piston aircraft.
What's the explanation for the huge drop in sales? Those single engine airplanes are still around? Deregulation of the airlines has resulted in cheaper commercial air travel? More telecommuting? What?
There was a terrible "aviation winter" in the mid-80s with product liability concerns, economic issues (high interest rates), and a spike in fuel prices resulting in the bankruptcy of several manufacturers and other manufacturers stopping the manufacture of piston-powered airplanes entirely.
To me, the more interesting question is "why were the 60s and 70s so good for GA?" De-regulation of airlines was probably one factor, but it can't be the only one.
I'm 45 and a pretty avid owner and pilot. For most airport activities (fly-ins, safety seminars, etc), I'm usually the youngest one in the room, often by a lot. I get the sense that wouldn't have been the case 50 years ago.
> To me, the more interesting question is "why were the 60s and 70s so good for GA?" De-regulation of airlines was probably one factor, but it can't be the only one.
Lots of WW2 pilots still alive and interested in flying in the 60s and 70s, maybe? I'm just speculating, but the population of flight-trained people in the country has probably not been higher than then.
I know a lot of veterans got pilot's certificates with the GI Bill education benefit, so that was probably part of it (in addition to conversion of military pilot experience into civilian certificates)
RE your last paragraph, I think cost is a HUGE factor preventing more young GA pilots. What's the cost to get a PPL these days? In the range of $5000-10000? And IIRC, the total operating cost per flight hour, even for something like a C-172, is north of $100?
Even as a young 30s software engineer with a comfortable salary and a PPL on my bucket list, it looks like a terrifyingly expensive hobby. The vast majority of people simply can't afford it.
Local flight school rents their 172s for $135-150 (depending on airplane), and based on my ownership experience, they're not making fat margins on that.
Very good question. Planes used to be so much cheaper, too.
I'm not an expert, but from what I gather there was this issue where product liability law suits drove aircraft manufacturers out of business. Even Cessna went bankrupt and was sold to Textron, and production of even the Cessna 172 stopped for a decade or so in the mid 80's.
The General Aviation Revitalization Act was supposed to fix this, not sure how much it has (see link at end).
Would love to hear more about this. Regulation is clearly a huge factor.
By the way, as much as one can complain about the general aviation scene in the USA (regulation, FAA, ...), on a global level it's still paradise. In Europe it's more complicated and expensive and cumbersome, even though the EASA is slowly moving in the right direction as far as I can tell. In Asia, general aviation is nearly unheard of. Australia has some, though it's really too big :-) Interestingly, Africa has pockets, e.g. in the south (South Africa, Namibia) and east (Kenya).
I have no expertise here, so this is just speculation. But I am thinking that it got to a point where everyone who wanted and could afford a small plane had one, they could be kept flying forever, and there weren't any major improvements so no reason to buy a new one. Plus, as a comment above said, small planes used to start with a military contract, and the military was switching to jets so you didn't see that anymore.
The Cessna 172/182 types are fine aircraft, but I really would have loved to have seen some more innovation over the years.
When I was a student pilot, we did our first handful of familiarisation and evaluation flights in a 172. The instrument panel looked like someone had cut holes in an ironing board and stuck dials in it. The seats were no more than a 2 piece metal bench that someone had stuck thin cushions to, and the seatbelts would have looked at home in a 1940's car.
Then we transitioned to the SOCATA TB-10 Tobago for the rest of our training. It was like switching from a Russian built car to a Lamborghini. The instrument panel was ergonomic, recessed for shade, and the engine instruments were actually canted to face the pilot. We had Recaro racing seats in the aircraft which made long navex's more bearable. Inertia reel seatbelts. Gull wing doors that helped cool the aircraft quicker after sitting on a hot tarmac all day. Throttle controls that looked like a jet fighter instead of pull knobs.
The European design was simply leagues ahead, and made the flying experience so much better. I am thinking a major reason for the longevity of the Cessna training line is more to do with cost for budget conscious training schools, rather than being a better aircraft than any other trainer.
> I am thinking a major reason for the longevity of the Cessna training line is more to do with cost for budget conscious training schools, rather than being a better aircraft that any other trainer.
Yeah, budget and familiarity. I doubt Cessna is selling many 172s to anything other than flight schools.
Your average flight school doesn't buy new 172s. Suckers with a lot of money do. (A new 172 costs over $350k last I checked. One a few years old can go for half.)
What flight schools do buy are the 172P, N and M, in that order. A low time 172P, being the last made before production stopped in the 1980s, commands a premium.
For those keeping count, that's a 55-year-old bird. Flies like a dream. In fact, we flew it last night. Recently put in a brand new engine. We'll be upgrading avionics soon enough, too.
I got my pilot's license this year, and hope to continue the tradition of flying my family in the plane.
(As a pilot: that one was a super pisser, the upper Cessna flew into the lower one and punctured the wing, rolling it over his engine, nothing the lower guy could have done. Thankfully the lower guy was wearing his seat chute (required on these kind of ops) and the upper guy (who wasn't wearing his required seat chute) managed to survive)
The 172 simply has some advantages even after all those years. First, it is known everywhere (also its quirks, which makes is safer). Second, the high wing makes it perfect for the young pilot to fly. And third, it has space! I, at 1.87 meter length, can sit comfortably in its back with some spare headroom remaining. I can't tell this of many other aircraft in a similar segment.
One answer comes from the fact that the Cessna 172 is a high-wing monoplane – meaning the wings sit high above the cockpit. This is very useful for student pilots because it gives them a better view of the ground and makes the aircraft much easier to land.
I had to think for a moment what a monoplane is. It's not a biplane.
Anyway, the high-wing design also causes the plane to fly level with regard to it's roll angle if you take your hands off the controls, due to the center of gravity being below the wings.
This is a completely inaccurate statement. The lift produce by both wings remains unchanged regardless of the roll angle. It is defined in terms of relative airflow over the wings, being always perpendicular to the former. Lift is NOT (usefully) defined relative to terra firma, a common misconception.
So in the relative frame of the aircraft itself, the lift vector is unchanged in terms of the machine itself. Rolling the aircraft rotates the lift vector, causing a larger "sideways" component and reducing the "vertical" component. For example, at 45 degrees bank the load factor is, in fact, 1.41, meaning that the wings ought to produce 1.41 times the lift to maintain altitude.
So the real reason why a dihedral tends to "auto-correct" the bank angle is that if you rotate the airplane into a bank without adding power then you really are not going to maintain your altitude against gravitational acceleration and are going to descend through the airmass. Now, given that your airplane is now at a 45 degrees angle relative to the source of gravitational attraction, the aircraft is going to see (from it's vantage point) some"sideways" airflow over the wings. Imagine an airflow component originating from the tip of the wing, towards the fuselage.
What now happens is that the "falling" wing is going to work much more efficiently because a number of reasons, causing the aircraft to experience an aerodynamically stabilizing force.
The easiest way to see is that if you imagine a V-shape object moving sideways (let's imagine from right to left), the \ part of the V is going to deflect airflow and produce some "sideways lift" while the / part will not exhibit such a phenomena.
But in terms of the 172, it's high-wing configuration actually does not require dihedral because the actual fuselage of the aircraft "shadows" the high wing, making in naturally less efficient at producing lift, thereby again correcting the bank angle.
Airplane designers attempt to balance this out so that the final design not only is statically stable (correcting in the right direction) but also dynamically stable (the oscillations should be self-limiting).
I'm not a pilot so this may seem like a silly question, but aren't the wings behind the cockpit? It doesn't seem like they'd be much of an obstruction to the view regardless of how high they are on the fuselage, unless pilots routinely look at the ground behind them (do they?)
Another great plane that has stood the test of time and is worth mentioning is the B-52. Over 60 years old and still being used extensively. One particular B-52 was piloted by a grandfather, father and finally son. What's more the B-52's are scheduled to keep flying until at least 2045 making a total lifecycle of 90 years!!
I think part of the reason we don't see new designs is they wouldn't be that much better. Often a technology advances rapidly, then hits a plateau where future improvements are just modest.
Think of jet planes, where everything since the 707 has just been a modification. That is why 50's and 60's planes like the b-52 and the a-10 are still flying. Or space rockets, where we are still just duplicating performance from the 60's (but with SpaceX we finally have something new).
Piston planes advanced very rapidly starting with the Wright brothers, but then hit the plateau in the 50's, and the next step up, jets, is just too expensive for most private pilots. Yes, it is possible to produce better small piston planes, but the sales are too small to justify the needed investment. Maybe electric planes will finally get us something new and better.
Airplaneheads often gripe that mass-media stories always glorify airframes and ignore powerplants. This story deserves that gripe. The story is actually about Cessna and Lycoming.
The Skyhawk airframe makes the machine easy to fly and land.
The Lycoming engine makes unplanned landings very rare.
Both are very important!
It really is an amazing airplane. In really cold weather in a 40 knot headwind I've gotten negative groundspeed in stable flight.
It takes real work to stall the airframe, and it recovers immediately if you let go of the controls.
How long till someone starts turning these into (relatively) cheap drones bombers? This is a proven aircraft, add bomb bay doors and a rack and release mechanism for 120mm mortar rounds. Instant 3rd world long range bomber, perfect for the warlord with a dirt strip and a mechanic. Airpower for the cost of ~10 technicals.
Any idea what the longest serving aircraft is? I believe there are still a small number of B52's in place, and they were rolled out in 1952. That's 65 years.
There are a ton of biplanes from the 1920s you can buy rides in. A friend of mine has a 1918 Curtiss Jenny that's mostly original. It's still flown and displayed at shows.
The airplane with the most time on it in the world is a DC-3 with over 100k hours. It's had the engines replaced with turboprops, like many of them.
When I was a student pilot in the early 90's a B-17 offering tours flew into my airport. Unfortunately I had my first solo cross country that day and no way was I going to miss it!
flightgear (free/opensource flight simulator) has it.
To get it started, press the engine primer 3 times, put mixture all the way in, throttle to 20% (+ throttle = 9, - throttle = 3), and turn the key twice (type "}}"), start it (s key), remove the parking brake (shift+B key). Then start increasing the throttle and when the airspeed indicator shows about 50 knots, go up by pressing the down key to take off.
While the article extols the virtue of the 172's engine, the fact is that the vast majority of them are running very old designs with carburetors and on Avgas. Avgas still contains lead. These old engines are hugely inefficient and flown incorrectly prone to cracked cylinders. Newer models are fuel injected and there are also a few diesel conversions.
All Cessna single engine aircraft now have to undergo supplementary inspections (SIDS), at least in Australia and I think it is the same in the US. I've seen first hand the horrendous amount of corrosion which can hide in a 50 year old aeroplane and not be found until the wings are removed. These SIDS inspections have the potential to ground much of the older 152/172/182 fleet and render what was a $25,000 asset practically worthless. It will be uneconomical to repair in many cases.
The above has happened to me personally with a Cessna 182. In the end it was sold for scrap with only the engine and avionics retaining any value. I've also seen the costs of these inspections on a Cessna 210 exceed $20,000. It needed a whole new main wing spar amongst other things.
The point I am making is that these very old single engine light aircraft need very meticulous inspections now to ensure they are still safe to fly. I do believe there are probably quite a few seriously at risk aeroplanes still flying today, especially if they have been left outside in coastal areas for any length of time.
I used to own a light aeroplane maintenance business.