This is related to my other thread, but wanted to branch off specifically into STOL airliners.

Are there any aircraft that has similar runway/take off STOL performance as the An-72 while carrying a similar or greater number of passengers?

I was looking at this list on wiki (I feel it may not be updated)
https://en.wikipedia.org/wiki/List_of_STOL_aircraft

and was surprised that it was rather unique being a comparatively large jet powered plane while all the others were much smaller prop planes

The short answer is: no.

Even An72 has a passenger ability more for a troops movements, since it was designed as one-off to operate from military airports. So, you will not find any standard plane capable of (such) STOL, as it affects fuel economy, payload, speed etc.

The closest would be probably modern military transports, but probably not to this extreme.

Cheers,
Adam

Perhaps the BAe146/Avro RJ. Weights are roughly comparable, but it has greater passenger capacity. Slightly shorter range.

It was also designed with STOL characteristics, albeit nowhere near as punchy as the An-72's.

NASA put jets on a deHavilland C-8A Buffalo...but that's substantially smaller than the An-72. (Google "NASA QSRA" if you're interested)



Even flew it off an aircraft carrier!
http://www.youtube.com/watch?v=k_eDutgh4IU



For something bigger, there is this guy:

The An-72 has good STOL performance, but the figures quoted on Wikipedia are not achievable with max payload - even the full Wiki article for the An-72 indicates a TOR of 620m.

So, within this bracket, you also have the Dash-7 which carries 50 pax and a TOR of under 400m and the Kawasaki C1/2 with around 500m.

^ thanks for the update! I also found out the upcoming ATR-42-600S (an STOL) variant, can also take off under 800m and carry about 50 passengers!

Should put more effort into working out how to get a 1500 m runway there so the community has the same access to emergency medical care as other people in Japan.

Practically, that's impossible I'm afraid, zeke.

The An-72 bears a resemblance (or is copied ? ) to the Boeing YC-14 a prototype design from the early 1970s (design submitted to the Air Force in February 1972) which had also used overwing engines and the Coandă effect.



See : https://www.avgeekery.com/boeing-yc-14- ... nced-good/

And for a video : https://www.youtube.com/watch?v=IndMz3grf8o

PlymSpotter wrote:

Practically, that's impossible I'm afraid, zeke.

Not impossible at all, can be built above water on piers like an elevated causeway.

Using the old WW2 area I think is more impossibke due to the rare widelife found there

zeke wrote:

PlymSpotter wrote:

Practically, that's impossible I'm afraid, zeke.

Not impossible at all, can be built above water on piers like an elevated causeway.

Using the old WW2 area I think is more impossibke due to the rare widelife found there

As the saying goes, nothing is truly impossible... however when you add in real world factors here, it becomes practically impossible to achieve.

A 1,500m runway places it into Code 3 aerodrome territory. There is no onshore location which can accommodate this. Complying with the necessary design standards to enable safe operation would require a runway to be located several hundred meters offshore, in water far deeper than it's currently technically possible to construct a simple pier, let alone one 150 meters wide and almost 2,000m long. This is open ocean, not a shallow river delta.

That’s just your opinion, my opinion is that it is technically very possible.

The runway itself would only neeed to be 1500x30m paved, the area around it could simply have steel decking. The purpose of the surrounding area is to support the aircraft in the event of a runway excursion.

Japan has a good history of building runways on water.

Again, it's not that simple. To extrapolate, your suggested 1,500 x 30m runway would require a footprint of 1,980m x 150m, or 1,980m x 300m for an instrument runway. With a 10m grid, this would require 3,184 piles or 6,169 piles, respectively, constructed 1,000km from the nearest deep water port. Just let the scale and logistics of that sink in for a moment.

Surfacing really is the least of any concern - the weight and force an aircraft produces is nothing compared to that which the ocean waves would exert on the supports. In addition to wave resonance and the water depth, you need to consider the significant wave height during major storms, meaning the runway plinth would likely need to sit at least 10m above mean sea level to avoid damage.

The fact is that driving piles is a good solution for the numerous global infrastructure projects crossing river deltas, with their combination of calmer waters, manageable depths, consistent mud and available support infrastructure, but for a seamount like Chichi Jima surrounded by coral sands, it is technically unfeasible and this is why you haven't seen it attempted anywhere else with similar conditions.

Sorry you are wrong, the whole area around the runway surface does not need the same load bearing capacity as the runway itself, nor is it required to be the dimensions you stated

Piles do not need to be 10 m apart, the weight of these smaller aircraft is lighter that normal vehicle traffic design except for the touchdown zone.

There is a big difference between what “required” and what is “recommended where practical”.

I hadn't argued against you on the point of bearing strength, so why are you telling me that I'm wrong on it? But for the record, yes the entire runway strip does need to be of comparable bearing strength - that's the entire point of it existing. If you are going to completely ignore recommended aerodrome design standards, then you might as well resort to making up any old nonsense. You of all people Zeke should know why this is a bad idea.

zeke wrote:

There is a big difference between what “required” and what is “recommended where practical”.

Touche and, to paraphrase, there is a big difference between what is technically possible and what is practically possible.

We're not talking about constructing a river or motorway bridge, the majority of pile and deck materials would be prefabricated on land, transferred to a ship, then conveyed 1,000km to a remote construction site where they would require a sizeable floating driver / crane to position. If you have any idea of the complexities involved in this, you'll understand why even a 10m spacing would be challenging.

But as you're so confident, I'm sure you'll be able to point me to a precedent instillation, where another deep water construction of this scale and complexity has been successfully executed using piles...

Engineering wise it is not that complicated, it has been done before, eg Madeira Airport



Thaey are proposing this sort of technology for Agatti Airport as well.

Sorry Zeke, well known as it is, Madeira is not similar at all - a completely different construction approach and a vastly different situation. I had a feeling you might propose this project however, it's actually an example of how piling wasn't practical even in shallow waters of the coastal edge.

On the original runway alignment, Madeira's extension would have required a construction almost completely over open water, but there were considerable challenges piling in this environment, which was a significant factor in why the runway was realigned inland. Even so, challenges remained and the remaining area of sea (14m depth) was then reclaimed in a cut-and-fill operation, to provide a level and dry construction base for the piling operation. For each support on the reclaimed land, a number of slender reinforced concrete piles were sunk, up to 60m deep, and filled with concrete pumped from trucks on this dry base. The piles together support a cast concrete pad, on top of which sits the cast concrete piers, which in turn support the girders and runway deck. It used something like half a million cubic meters of concrete, which was prepared on site using local materials, aside of the cement and re-bar component, which had to be imported. This actually in itself is a major problem, as the materials are substandard and parts of Madeira's original airport are now badly degrading.



Agatti offers some precedent - it is quite distant from the mainland. However the waters are shallower and offered protected from the open ocean by a coral reef, meaning the construction required would be much less substantial. Also, I'll believe it when I see the extension opened.

Perhaps you can think of others which are directly comparable.

They are directly comparable, engineers can vary how piles are constructed for the site.

The choice of the piles was not driven by design, it is driven by cost.

You're very much missing multiple points here Zeke.

The projects are demonstrably non-comparable - as I've explained in detail. To support your suggestion, I asked you to identify a precedent which was in deep water, as complex a design as your are proposing, and equally remote. You produced an example built on dry land, nowhere near as complex and where the vast majority of raw materials were readily available on site. This is like asking someone to produce a car, only to be given a soap-box instead - it's not what I required, and now the wheels have come off.

I suggest we park this conversation, to avoid piling yourself a deeper hole.

It isn’t all deep water, there is a number of locations that have less than 10 m depths. For example between Minamijima Island and Chichijima Island.



In terms of prefabricated decks being transported by surface, there were numerous sections moved for the new elevated causeway for the new Hong Kong-Zhuhai-Macau link that are over 130 meters long, 3200 tonnes. They were built on land, placed on a barge, transported, and lifted by floating crane.

There are various examples where bridges and causeways were built with prefabricated sections and lifted in place by a floating crane. These are far more complex compared to a structure which essentially just needs to support the weight of a heavy truck.

http://www.yooshin.co.kr/english/busine ... ure_01.asp

How far out does the world heritage site designation extend? All of this discussion may be moot if the waters themselves are also under the environmental protection of the site designation.

Again, you're missing the key practicality and feasibility issues.

The Zhuhai bridge is constructed in a shallow river estuary, surrounded by relatively calm coastal waters. Perfectly acceptable for mega-barges to operate in this area, or even along the Chinese coast where shelter is available, carrying or towing vast pre-cast sections of concrete. Same as the Oresund crossing, or the Busan-Geoje fixed link, plus many others around the world. But you don't want to be doing this across 1,000km of open ocean, for reasons which should be obvious!

You also don't want to be going anywhere near a rough seabed like that in Chichi Jima - you'd first need to dredge the entire area to a consistent depth, and remove the rocky outcrops, to enable the equipment to access without floundering. In other words, not a very workable idea because it's as ecologically destructive as land reclamation.

Btw - your thinking on the loading is very wrong. Firstly, trucks are designed to spread their weight across more pressure points - anything around the 40,000kg mark will have five-six axles and likely spread that weight across 12 or more wheels. If the critical aircraft is the A220-100 at MTOW (or -300 at lower TOW), that's just under 61,000kg, focused on three points and six wheels - a substantial difference when it comes to deck construction and the point loading it must support. But of course, a truck's loading is essentially static - it isn't going to accelerate to 150mph or just fall out of the sky from 50ft, whilst aircraft deliver shock loading, which means your piles have to find solid ground (bedrock), or they will gradually sink further into the ground and compromise the structure. To withstand potential accidents, the structure would need to support at least three times the maximum expected static load, across the entire runway strip, so in this case call it 200,000kg to add some margin, or just under 2,000kN. That's a good five times greater than your standard heavy truck.

PlymSpotter,

It is highly amusing to read the backflips in your posts, you have gone from water that is too deep, now to water that is too shallow that it requires dredging.

The construction techniques would be planned for after a survey, and then design was made. Where to site a runway can only be determined afer a full survey has been completed. I cannot say where and how they could build it unless that sort of data is available. My posts were purely to highlight an alternate technically feasible way the runway could be constructed. I have no say on what they will do in the end, and what the trade off will be between costs and environmental considerations.

Ocean going barges are designed to carry significant loads in the open ocean, something that is done on a regular basis, a lot of different company’s have them available. I did also show a link to a number of large projects in Korea.

Airport bridges are designed using road design specifications, these are designed for multiple simultaneous vehicles where a runway is normally designed just for a single aircraft. Landing loads are actually ignored when designing airport pavement, aircraft land with less fuel and therefore less weight, and the remaining lift on the wings helps alleviate the dynamic load effects of touchdown impact. They use of the maximum anticipated takeoff weight for design.

This is hella off topic at this point. Why don't you guys agree to disagree. It's clear zeke will never see your point, not matter what evidence you show him. Call it a draw and get back to the topic.

A relatively fast Do328 can operate from 1,200m runway.

An runway on piles seems possible on a purely technical basis but looks unfeasible when factoring in cost, population size, and the "inconvenience" of a World Heritage Site.

Zeke's proposed location is a heritage site.
https://whc.unesco.org/document/115725

Well Zeke, I can only respond to what you are saying - the entire environmental point of a runway in the ocean is to clear all obstacles and the sensitive onshore and marine shore environments. Choosing a transitional site too shallow for anything other than a dirigible is clearly also inappropriate - try operating incredibly expensive marine construction equipment in waters clearly filled with partially submerged rocks; that's only going to end badly and with a very difficult to explain insurance claim!

Regarding loading, as I've said, you do indeed calculate from MTOW. The assumption has to be worst case; an aircraft impacting the runway/strip heavily, at or near-to MTOW, for whatever reason during an accident, be it upon take-off or (emergency) landing. Road decks are normally engineered to no more than 150% of design load, so this would not be acceptable. You may be interested to learn that this is the approach the team took at your precedent, Madeira, due to the higher likelihood of an emergency return by the critical aircraft (B747-400), soon after take-off.

But as I've said several times in this thread, anything is technically possible - it comes down to the practicality and feasibility. My experience is that nothing anywhere near this complex has ever been attempted before in such a remote location and, despite several attempts, you've not been able to demonstrate otherwise. So whilst technically yes it's achievable and feasibly yes it's also impractical, at this point I believe 426Shadow has it nailed - I've already suggested we park this conversation, so lets actually agree to disagree here and move on.

Pacific wrote:

A relatively fast Do328 can operate from 1,200m runway.

The Do328 operates since its introduction into service from Mannheim City Airport in Germany, which has a much shorter runway:

09/27 1066 m × 25 m Asphalt

It's a ride on a hot rod in and out of that airport, but a loooooooooot of fun!


While Cirrus Air operated the routes to Berlin and Hamburg you got roundtrip tickets for 97 Euros. Then they went into insolvency and now Rhein-Neckar-Air is operated the aircraft on the same routes, but with prices 3 to 4 times as high. Load factors don't seem to have changed much, so while bad for the pax, it seems the new airline is doing a better job with the high-priced tickets than Cirrus did back then.

CARST wrote:

The Do328 operates since its introduction into service from Mannheim City Airport in Germany, which has a much shorter runway:
09/27 1066 m × 25 m Asphalt

Yeah you're right as the basic takeoff spec at MTOW is at 1,088 metres sp 1,066 metres would be enough for short intra-Europe routes
https://328.eu/wp-content/uploads/2013/ ... boprop.pdf

For a hypothetical operation at Chichijima, it is 600nm to Tokyo plus winds and a generous fuel allowance for alternates as Chichijima is an isolated island. That would mean a Do328 would be near its MTOW/MLW. Temperatures are also frequently above 30c (ISA+15 and above) which also adversely affects takeoff/landing performance. All that would mean the runway would need to be longer than the marketing spec.

Therefore, an armchair enthusiast, I'm assuming 1,200 metres would accomodate a Q200 and D328 while the hypothetical ATR42-600S can operate safely with 1,000 metres. Doubt An-72 is suitable due to Russian aircraft having notoriously poor aftersales support.