A plane so good it's still in production after 60 years
bbc.com
bbc.com
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.
I now work in pharmaceutical engineering R&D, breed thoroughbred horses and mess about with data science.
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....
:)
You really should write a book or something like that. I'd be happy to read it.
Inspiring!
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.
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 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.
How do you avoid that, i.e. "fly correctly"?
Do you recommend cylinder temperature gauges?
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.
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.
http://www.gami.com/paulferraris_leanofpeaksaga.pdf
In any case, the Cessna 172S Lycoming IO-360-L2A (engine) handbook says, "Continuous operation at mixture settings lean of peak EGT is prohibited"
See the blue line in the graph here: https://www.advancedpilot.com/redbox.html
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...
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.
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).
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.....
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 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.
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..
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.
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.
Unfortunately Turboprops come with a whole new set of maintenance requirements but otherwise it's an excellent aircraft and working out quite well.
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.
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".
Certain activities are inheritently dangerous, unless you get regular practice, statistics will eventually cause a fatality someday.
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:
https://www.casa.gov.au/standard-page/questions-and-comments...
https://www.casa.gov.au/standard-page/questions-and-comments...
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:
https://www.ntsb.gov/about/employment/_layouts/ntsb.aviation...
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.
http://www.flightsafetyaustralia.com/2015/06/24-march-20-may...
I'd be interested in reading a source for this, because that would be pretty big news.
Really? The Cirrus SR20, SR22 don't count? Haven't they been outselling the 172 for several years now?
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.)
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.)
Pilot in command ultimately responsible, but damn, ATC did her no favors that day.
http://www.kineticlearning.com/pilots_world/safety/06_05/art...
See www.wmich.edu/aviation
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.
- 400 Cessnas, of which 90 C-172 and 120 C-182
- 200 Cirrus, of which 160 SR22
- 60 Diamonds, of which 50 DA-40
http://www.controller.com/listings/aircraft/for-sale/categor...
http://www.controller.com/listings/aircraft/for-sale/categor...
http://www.controller.com/listings/aircraft/for-sale/categor...
http://www.yachtworld.com/core/listing/cache/searchResults.j...
Hard to beat the roomyness of the 172 (for it's class)
Phil Greenspan has a nice review (though a decade old):
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.
sure, but the parent was asking about a DA40 vs 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.
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.
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.
https://www.gama.aero/media-center/industry-facts-and-statis...
https://www.wired.com/2015/09/blame-faa-blunder-lack-electri...
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).
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.
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.
https://en.m.wikipedia.org/wiki/Energy_density has a comparison. Lithium air batteries are in the extended reference table here https://en.m.wikipedia.org/wiki/Energy_density_Extended_Refe...
From https://en.m.wikipedia.org/wiki/Lithium–air_battery :
"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).
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.
Having to throw away that first engine design could have been survivable if the economy didn't get so sucky so fast.
Most of them were shelved, only the HondaJet is still being produced (in small numbers).
As they say: The way to make a small fortune in aviation is to start with a big one.
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.
Local maxima != 'reduction'.
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.”
"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.
http://www.usatoday.com/story/news/nation/2014/06/14/unfit-f...
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.
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.
Small plane / general aviation design is a complete mess. Even the fancy new 172SPs are still using engines with 1950s manual spark plug timing.
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.
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.
1. https://en.wikipedia.org/wiki/Pontiac_Chieftain#First_Genera...
2. https://en.wikipedia.org/wiki/GM_Family_0_engine#Generation_...
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.
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.
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.
I guess I'm wondering if there's a grassroots community of people doing engine swaps on their planes?
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.
The Oshkosh eaa meet was always a lot of fun to go watch when I used to live in WI.
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).
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)
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.
[1]http://www.cbc.ca/news/canada/calgary/kenn-borek-air-south-p...
[2]http://www.cbc.ca/news/canada/calgary/kenn-borek-air-south-p...
[3]https://fearoflanding.com/misc/twin-otter-emergency-winter-f...
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.
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.
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.
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.
That said, here's a C130 that flew for 52 years: http://foxtrotalpha.jalopnik.com/usafs-oldest-c-130-hercules...
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.
I'm genuinely interested in the explanation.
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).
https://en.wikipedia.org/wiki/General_Aviation_Revitalizatio...
https://generalaviationnews.com/2015/05/31/analyzing-statist... has some decent (and short read) background on the overall trends.
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.
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.
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.
Nowadays the interest is not there and the training cost is high. These WW2/Korean pilots got free training from the military.
To see what we are missing, Just take a look at experimental aviation which is not as heavily regulated..
*I did most of my basic training on a 172 and I love them like I love a favorite old pair of shoes.
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.
Yeah, budget and familiarity. I doubt Cessna is selling many 172s to anything other than flight schools.
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.
Take care of stuff and it can last a long time.
I think they've got their Cessnas in a muddle. The 140 was a taildragger. I learnt to fly in a 150 which definitely had a wheel at the front.
My first skydive (static line), and many after that, was from a 170.
https://www.youtube.com/watch?v=kQ6g_TcevCE
unedited/better video: https://youtu.be/7p6hqMnsLFY?t=81
(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)
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.
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).
Tradeoffs I suppose.
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.
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.
all the B-52s still in service are B-52Hs and deliveries of the H didn't start till 1961.
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.
https://en.wikipedia.org/wiki/List_of_surviving_Boeing_B-17_...
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.
Do not try in an actual plane.