Design challenge: next generation heavy-lift cargo plane?

[riggerrob]

Given the recent destruction of the only Antonov 225 super heavy lift cargo plane ... what will the next generation of heavy lift planes look like?
What is the biggest cargo they will carry?
What is the widest cargo?
Tallest cargo?
Longest cargo?
Heaviest cargo?
How heavy?
How fast?
How long range?
Minimum runway length?
What type of doors, loading ramps, etc.?

We can start by reviewing Conroy Super Guppy, Airbus Beluga, etc. but let's see some "flights of imagination."

 

[Archibald]

-High-mounted wing (like a C-5 / An-124 "classic shape")
-4*GE90 for max power (50*4 = 200 tons thrust or even more)
- range 6000 to 10 000 km if that possible.
-nose cargo door like the 747-200F / C-5 / An-124
-nosewheel "kneeling" system for practical loading
- classic rear cargo door / classic undercarriage with a crapton of wheels
- A380 dimensions not to exceed civilian airport limits in span, height, weight, length (seems to be 80 m * 80 m * 24 m * 600 metric tons)
- fuselage diameter: A380 is proof 7 m is feasible, so why not ?
- don't try to go the STOL way: the C-17 is already there and doesn't use that capability a lot

-Such a big beast should be able to lift a bit less than 200 mt across the Atlantic or 120 mt over 10 000 km or more.

Later makes the ultimate variant, An-225 style: with larger span and 6*GE90 and 300 mt payload over short distance.

Compared to such classics freighters as the An-124 / C-5 / 747 advantages are
- 2022 tech level, rather than 1965 or 1980
- engines with max power (50 tons rather than 25 or 30)
- engines with optimal fuel consumption
- larger fuselage diameter (7 meters instead of 6 m or less)
- optimized span and length right from the begining; maxing out civilian airports limits

 

[kaiserd]

There’s an aspect worthy of consideration/ discussion in this context.
Beyond risk/ reward consideration of potential non-traditional airlift configurations there is is a parallel (and not unrelated) consideration of what materials etc. to use.
Essentially the options of further gradual evolving, say of the materials and structure of a C-17, or instead attempting a large jump with much more radical use of composites (further beyond, say, the 787 taking an example).
The risk/ reward dilemma here is complex, particular if very large commercial airliners don’t lay the ground work first (i.e. how radical B777 and A350 successors end up being in this regard). The production numbers for any new heavy airlifter are going to be relatively small and their relative priority is never likely to be that high - hence limited research etc. available to be invested unless can feed off or be justified by supporting wider applications.
Such a context may be seen to encourage a more conservative approach, to dust off and improve existing designs, leverage existing less exotic materials, structural design etc. However that approach would have it’s own risk/ reward issues linked to the large time gap since the last very large airlifters (An-124, An-225, C-5) were designed and built (and that was before recent events in Ukraine). Essentially there will now be very limited available design & engineering in-person experience from these programs that can still be directly and effectively leveraged (apart from the more recently in production smaller airlifter programs like the C-17). And that issue will get worse as time goes by.
Hence even going down a more conservative path has its own considerable challenges and risks that may not be that less riskier than more radical paths but which don’t offer the same rewards.
So perhaps this is just a long winded way of saying I see 2 general options available;
- A relatively conventional looking airlifter or airlifters based on the technology (and potentially the engines and some of the structures) of the B777/ A350 successor generation of large airliners, or
- Something a lot more radical

 

[Hobbes]

Comparison of the loading gauges of current large transports:

 

[red admiral]

Stratolaunch with a big fairing between the fuselages...

 

[Archibald]

There’s an aspect worthy of consideration/ discussion in this context.
Beyond risk/ reward consideration of potential non-traditional airlift configurations there is is a parallel (and not unrelated) consideration of what materials etc. to use.
Essentially the options of further gradual evolving, say of the materials and structure of a C-17, or instead attempting a large jump with much more radical use of composites (further beyond, say, the 787 taking an example).
The risk/ reward dilemma here is complex, particular if very large commercial airliners don’t lay the ground work first (i.e. how radical B777 and A350 successors end up being in this regard). The production numbers for any new heavy airlifter are going to be relatively small and their relative priority is never likely to be that high - hence limited research etc. available to be invested unless can feed off or be justified by supporting wider applications.
Such a context may be seen to encourage a more conservative approach, to dust off and improve existing designs, leverage existing less exotic materials, structural design etc. However that approach would have it’s own risk/ reward issues linked to the large time gap since the last very large airlifters (An-124, An-225, C-5) were designed and built (and that was before recent events in Ukraine). Essentially there will now be very limited available design & engineering in-person experience from these programs that can still be directly and effectively leveraged (apart from the more recently in production smaller airlifter programs like the C-17). And that issue will get worse as time goes by.
Hence even going down a more conservative path has its own considerable challenges and risks that may not be that less riskier than more radical paths but which don’t offer the same rewards.
So perhaps this is just a long winded way of saying I see 2 general options available;
- A relatively conventional looking airlifter or airlifters based on the technology (and potentially the engines and some of the structures) of the B777/ A350 successor generation of large airliners, or
- Something a lot more radical

On paper at least, Airbus could mix their A380 and A400M experiences to design a new "military freighter colossus".

Perhaps starting from the A380 fuselage and tooling - but it would need two massive changes
- the fuselage guts (as explained elsewhere) would have to be redesigned
- the wing would need to go above the fuselage, not below.

The magnitude of changes would be akin to Boeing a) C-5 bid and b) 747-200F - mostly unrelated because of massive design changes. to go from civilian to military heavy lift.

Much more annoyingly, the market for such aircraft is too small at least in Europe. European air forces are not rich enough, and the civilian oversized cargo market (as shown by the An-124 / 225 experience) certainly exists but is too small to justify a brand new aircraft.

 

[Nik]

Scott / OBB should be able to wheel out several classic 'low-boy' designs...

 

[kaiserd]

A duopoly of US (with UK, European and other partners - a bit like the JSF/F-35 program but just for the one version with shared percentage of program for partners to commit to orders to make the US program more viable and harder to cancel) and China (maybe with Russia as a junior partner?) heavy airlifters may emerge, maybe…

 

[Hobbes]

Another sheet from the same presentation as above, I added the loading height for each aircraft. Values in black were measured from the PDF (and very approximate because of the low-res source material), values in blue found on the internet. Surprisingly difficult to find this info.
Edit: found the correct value for the Belugas, this is 5.0 m.

 

[riggerrob]

Those high floor levels increase the need for specialized loading equipment and slow loading.

As an alternative, I was wondering about a radically different concept.
What about a separate cargo floor?
The separate cargo floor is basically a pallet that lays on the taxiway until the super-sized cargo plane taxies over it. Fuselage side walls can be hydraulically bulged to slide outboard of the pallet. When directly over the pallet, the side walls swing inboard and clamp to the pallet.
External, hydraulic struts may be needed to transfer loads from wing roots to fuselage side walls.
The cockpit will be permanently mounted on a high spine (ala. Lockheed C5A Galaxy), so that it is 8 or 10 meters above the taxiway. All control lines remain fixed to the upper spine. The structural spine connects all the flight loads between cockpit, wings and tail.
A quick-detach nose cone streamlines the front of the cargo and a similar cone streamlines the rear of the cargo. If the airplane cruises slow enough, they might even be inflatable.
Landing gear loads are transmitted straight up the side walls. Nose wheel(s) are attached to the forward ends of fuselage side-walls.

 

[Nik]

{ Cough...} Thunderbird 2 ??

 

[Foo Fighter]

I cannot see stratolaunch for the general or super heavy roles, the average location to transit to and from would need too much upgrading. Something along the lines of current trends with the heavy end by a 224 copy/upgrade.

The risk of producing another A/B 400M might just be one risk step too far.

 

[Hobbes]

Those high floor levels increase the need for specialized loading equipment and slow loading.

As an alternative, I was wondering about a radically different concept.
What about a separate cargo floor?
The separate cargo floor is basically a pallet that lays on the taxiway until the super-sized cargo plane taxies over it. They can be hydraulically bulged to slide outboard of the pallet. When directly over the pallet, the side walls sing inboard and clamp to the pallet.
External, hydraulic struts may be needed to transfer loads from wing roots to fuselage side walls.
The cockpit will permanently mounted on a high spine (ala. Lockheed C5A Galaxy), so that it is 8 or 10 meters above the taxiway. All control lines remain fixed to the upper spine. The structural spine connects all the flight loads between cockpit, wings and tail.
A quick-detach nose cone streamlines the front of the cargo and a similar cone streamlines the rear of the cargo. If the airplane cruises slow enough, they might even be inflatable.
Landing gear loads are transmitted straight up the side walls. Nose wheel(s) are attached to the forward ends of fuselage side-walls.

Hasn't this been tried already, albeit with pods? There was a US military cargo aircraft that did this, wasn't very successful again because of the need to preposition the pods.

 

[uk 75]

As I recall the An225 was the result of very specific requirements of the Soviet Union to move around the sort of big stuff it was famous for needing to get to remote parts.
China seems the closest to the old USSR in needing to do this on a regular basis.
China would have no scruples about getting hold of Antonov when the rubble clears and seems to me the most likely candidate to build an updated An225.
The US, EU and UK have then to see how often they need something bigger than a C17 or Dreamlifter. Depending on who the people needing the lift are will indicate how the problem is solved.

 

[TomcatViP]

I think Europe as straightforward fast path for that: re-use the A380 wing and build around a new fuselage. Most of those wings will never reach their full potential. Harvesting them seems even logical, cutting cost and delay.
Alas, a small budget project might not even been deemed interesting to be discussed.

 

[Nik]

IMHO, China may, while Airbus could...

Sadly, I reckon anything Boeing offer would be shunned, due near-certainty of dire cost over-runs, while limping in a decade late...
{ Shakes head... }

 

[TomcatViP]

Some design proposals, more or less related to Airbus capital, surfaces around modified A380's.

One option would have a shoulder mounted opening cargo bay, a la Orbiter (Space shuttle).

Avion-cargo XXL : Des Airbus A380 pour remplacer l’Antonov An-225 - Aerobuzz

Airbus a lancé l’étude de la transformation des A380 en version cargo (P2F, Passager To Freight). L’objectif du constructeur européen est de se positionner sur la niche qu’occupait l’An-225 avant sa destruction lors d’un bombardement, en Ukraine. Cette idée d’offrir une seconde chance au super...

www.aerobuzz.fr

 

[MadRat]

C-17 can be modified if we need something bigger. They can always up-engine it and stretch it. There is absolutely no reason to do a new design from scratch. If Europe neefs something then they should just stick to C-17, too. Airbus has been a disaster as a design house.

 

[Hobbes]

Some design proposals, more or less related to Airbus capital, surfaces around modified A380's.

One option would have a shoulder mounted opening cargo bay, a la Orbiter (Space shuttle).

Avion-cargo XXL : Des Airbus A380 pour remplacer l’Antonov An-225 - Aerobuzz

Airbus a lancé l’étude de la transformation des A380 en version cargo (P2F, Passager To Freight). L’objectif du constructeur européen est de se positionner sur la niche qu’occupait l’An-225 avant sa destruction lors d’un bombardement, en Ukraine. Cette idée d’offrir une seconde chance au super...

www.aerobuzz.fr

Translation:

What is more saddening? Discover the smoking wreckage of the only copy of the An-225 Mriya on social networks or attend the dismantling of the first Airbus A380s in Tarbes? In both cases, the spectacle is distressing…

The Ukrainian manufacturer has launched a subscription to raise the funds necessary for the construction of a new An-225. We are talking about 3 billion dollars. Although the images have moved aviation enthusiasts across the planet, the bet, which is raising controversy, is far from won.

The disappearance of the An-225 comes at a time when the market for cargo planes is exploding. To meet unprecedented demand, both Airbus and Boeing recently launched freighter versions of their next-generation large jets (A350XWB and 777X). They also favor the transformation of passenger planes into freight transport. This business has never been so flourishing. The P2F, in other words “Passenger To Freight”, opens up new financial prospects for aircraft lessors. Boeing multiplies the conversion chains of 737 and 767 in the world. Airbus got into it with the A320. And even Embraer has just announced the launch of the E190 P2F.

Why not do the same with the A380? The question, which had been postponed until then by Airbus, now arises all the more acutely as the disappearance of the only aircraft capable of transporting oversized loads has created a void. It is no longer a question of transforming the A380 into a simple cargo plane, but of making it a super transporter, a sort of Beluga XXL. In Tarbes, Tarmac Aerosave, which took delivery of the first A380s from Singapore Airlines for dismantling, proposed to Airbus, its parent company, a transformation scheme based on the Beluga XL model. The challenge is to create the greatest possible volume in the hold.

The floor that separates the two decks of the A380 jumps, and its fuselage has been redesigned like that of the Beluga XL, to offer greater interior volume. The position of the cockpit prohibiting the solution of the nose which is raised, Tarmac Aerosave proposed that the hold opens like that of the American space shuttle, that is to say over its entire length, on the upper part of the fuselage. Beautiful loading images in perspective… However, even if communication is a fact that an aircraft manufacturer never neglects, let alone Airbus, the interest of this formula lies elsewhere. It will indeed be possible to load very large jigs. What Boeing cannot do with its DreamLifter, the super transporter version of the 747-400. Airbus is considering this future super cargo ship to transport the hydrogen tanks of its aircraft of the future across Europe.

It would be a great revenge for the A380! At this stage of the project, all that remains is to launch a subscription to make the decision.

 

[riggerrob]

What if you "borrowed" enough wings and engines from a huge (Boeing 747 or Airbus A380) to build a huge biplane like Dee Howard's DBA? There is a DBA thread in Post War Projects.

 

[BAROBA]

I think we should focus on the design, not if someone is going to buy it or not...
Would a flying wing like plane make a chance? The cockpit is the only area that really needs pressuring? The rest of it only needs to be structurally sound.. Advantage: You get more range and heavier lift capability due to the shape. Concern: you need to keep the wingspan within the limits.
Good idea?

 

[Silencer1]

Hello!

My two cents:
1) there is a difference between military cargo aircraft, that should be able carry, load-unload, paradrop extra-heavy and compact loads (tanks etc.) and civil cargo-haulers, intended to transport relatively lightweight but very volume-consuming loads (like fuselages, wings, other fuselage parts). So, An-225, Il-76, C-5 belong to first group, and Guppys, Belugas, Dreamlifter - to another. So, the fusleage cross section area and dimensions, as well as cargo floor capabilities are differs also. As well as undercarriage - which on military types is the one of the key components in their abilities to cargo hauling.
2) Guppys, Belugas, Dreamlifter have been bulit for and by their respective customers, in order to transport their own, quite specific payloads (I guess, the word "pay" coul be omitted). If the size of new components would changed or increased and they wouldn't fit in current Beluga - I'm prettry shure, that Airbus produce larger Beluga... But size of military equiment are relatively constant, moreover, their transporatbility by air has been taking into account at the first stages of design.
3) there were cargo (construction machines, generators etc.), that outsize and outweight military equipment, but stll are could be trasnported by the air, and thus lower expenses for delivery.

I think, that "civil" cargo-lifters built for aircraft-production companies own needs would still emereged in small numbers, while miltary cargo-lifrers (and their civil versions) woul be bulit by dozens.

 

[Nicknick]

If I could start from scratch, I would design the plane for maximum lift capacity instead of aerodynamic efficiency and speed. The plane should be able to use ordinary runway length because these planes were often used to transport big machines close to remote areas. Range shouldn’t be very important, because the cost for intermediate refuelling will be acceptable and time isn’t the main concern if preparation and planning take month.

The really huge Antonovs have never been very busy and flown on schedule, usually they have been in waiting modus until the next trip was done (with a lot of organization work in advance).

So my proposal would be an high wing aircraft with extreme wingspan which can be realized by a brazed wing design (not as old fashioned as you might think: https://www.sae.org/news/2019/01/bo...rodynamic-transonic-truss-braced-wing-concept). The propulsion should be turboprop (so more, so better) because they offer a better acceleration and more lift on the wings than jets, which is very helpful for maximizing the maximum take off weight.

Custer channel wings could be an interesting option, but they are structural very critical and might not be suitable for large aircrafts.

 

[BAROBA]

I have made a concept of a future(istic) heavy lifter.
As I am an artist and not a mechanical engineer, things could be wrong.
Feel free to give some input.
I based my design on that of a flying wing, but those with a separate cockpit above the nose and a belly to carry stuff.
The nose is equipped with 2 clamshell-doors that open to reveal a huge interior.
The internal volume is enough to carry a 7m diameter tube that is 30m long.
The tail can house a loading ramp. (But can not offload that 7m diameter tube.)
There are 6 turboprops ( thanks Nicknick for the idea) that have a 6.66m diameter ( The devil really is in the details propeller. ( I know next to nothing about turboprops and how big they should be..Any help here?)
The engine pylons also act as tails to keep the plane on course.( I think they are too thick?)
I think the plane will make very smooth landings with that enormous wingsurface.
Comments are welcome

 

[Nicknick]

Nice, but the wings need to be moreV-shaped. The outer part of the wings must produce downforce whereas the inner parts produce lift more to the front (for stability). To keep the downforce more behind and the lift more to the front, I would recommend a more V-shaped configuration as seen in most flying wings.

One problem with a tailless design is the narrower range for the centre of gravity in longitudal direction (important for heavy load planes). I think it would work better, if you reduce the wing size and put them more afterwards so that you can add canards in the front.

Another problem with flying wings and canards (?) is, that you can't use flaps, so despite the large wing, the critical maximum lift during take-off and landing is lower than with a conventional design. I have to say, I’m not sure about the canards, here, flaps might be possible because you can counteract the increased lift in the back with the canards to a certain degree.

The pusher engines in your configuration don’t add a lot of lift at low speeds, unlike propellers in the front of the wing.

 

[TomcatViP]

Your creative view on how RoRo* is done today is interesting. I see that idea of loading bulky cargo from the front only a very acceptable compromise that could open aerodynamics and balance advantages**

*Roll In Roll Out

 

[Hobbes]

The rear ramp is an advantage for military operations, but commercial ops don't need it as much. IIRC on the An-225 the rear ramp was deleted.

 

[sferrin]

C-17 can be modified if we need something bigger. They can always up-engine it and stretch it. There is absolutely no reason to do a new design from scratch. If Europe neefs something then they should just stick to C-17, too. Airbus has been a disaster as a design house.

IIRC the entire plant is gone. (I think Relativity Space is in it now.) May as well start with a clean sheet. Give it to LM as they know how to build large military cargo aircraft.

 

[TomcatViP]

The rear ramp is an advantage for military operations, but commercial ops don't need it as much. IIRC on the An-225 the rear ramp was deleted.

Yes, but he is envisioning a smaller section for the rear cargo door, something, I guess, sized for military vehicles out of the back but slightly more tolerant for extra bulky cargo loaded from the front.

 

[riggerrob]

I have made a concept of a future(istic) heavy lifter.
As I am an artist and not a mechanical engineer, things could be wrong.
Feel free to give some input.
I based my design on that of a flying wing, but those with a separate cockpit above the nose and a belly to carry stuff.
The nose is equipped with 2 clamshell-doors that open to reveal a huge interior.
The internal volume is enough to carry a 7m diameter tube that is 30m long.
The tail can house a loading ramp. (But can not offload that 7m diameter tube.)
There are 6 turboprops ( thanks Nicknick for the idea) that have a 6.66m diameter ( The devil really is in the details propeller. ( I know next to nothing about turboprops and how big they should be..Any help here?)
The engine pylons also act as tails to keep the plane on course.( I think they are too thick?)
I think the plane will make very smooth landings with that enormous wingsurface.
Comments are welcome

Trust an amateur to invent a viable solution.
Your drawings remind us of the Horten Brothers' DINFIA IA 38 Naranjero. They built that huge flying wing to haul oranges (fruit) from their orchards to market. It first flew in 1960 in Argentina.

One advantage of that huge flying wing is that it provides plenty of wing area to produce excess lift that allows for slow take-off and landing speeds. Yes, it has too much wing drag for high-speed cruise, but who cares about cruise speed when your primary mission is delivering "impossible" sized cargo?????
Flying wings do require more precise balancing of cargo, but canards or tail feathers are still optional.
That huge wing volume will allow you to install a variety of "trim" fuel tanks (ala. Concorde SST).

Conventional swept winged flying wings use wing twist to help with pitch stability. OTOH, planks (ala. Backstrom and Fauvel) and deltas (e.g. Dyke and Verhees ) use stable airfoils that do not need external control surfaces (canards or tail feathers) for pitch stability.
Swept flying wings use conventional (pitch unstable) airfoils, then twist wing tips to improve pitch stability.
You can get the same pitch stability by installing helicopter blade airfoils that are reflexed (trailing edge curved up) and already self-stable in pitch, without external control surfaces.
Your design already has plenty of tail moment arm length to help with pitch stability.

Your long, parallel cargo-compartment side-walls provide a convenient place to mount a dozen or more low-pressure tires ... to reduce point-loading and protect soft asphalt runways. The long foot-print also helps with stability on the ground. If you want to get fancy, you can vent air from tires and landing gear struts to "kneel" the airplane for loading.

With that thick wing, you don't really need a separate, semi-submerged fuselage protruding from the top skin of the wing. The wing is probably deep enough to conceal a cockpit without any added height. Just install plenty of windows in the center leading edge and mount the pilots' seats far enough forward that they can see their own wing tips.

At first glance those pylon-mounted props look like something "borrowed" from Mr. Bel Geddes airliner proposal of the 1930s, but they do carry a certain logic in that they allow "borrowing" large, tractor, turboprop engines from existing production airframes (e.g. Tupolev 95 BEAR bomber).
Pylon-mounted rudders might help during cross-wind landings, but you are probably still going to need drag-rudders mounted on wingtips (ala. Northrop flying wings).

Since the primary function of winglets is to increase wing span (and aspect ratio) you are probably going to need taller winglets.

I have tried to provide an encouraging critique of your proposal. It has merit. The only things that I would change are "sinking" the cockpit and increasing the height of winglets.

 

[helmutkohl]

an alternative idea..

do we really need something as large as the An-225 again? It seems like a very niche aircraft.

I like the idea of the Kawasaki C-2. it has roughly a similar payload and range as the old Lockheed C-141 (and I guess Il-76?)
but done with two engines which could be more economical for air forces to operate.

can we scale this up a bit further? perhaps C-17 size?

 

[yasotay]

Just recall as part of the design, that the weight of the platform and cargo must be well distributed for landing and takeoff or you will find the number of locations the aircraft can operate will be significantly restricted.
What are the standard weight restrictions (if there are such) for commercial airfields?

 

[apparition13]

C-17 can be modified if we need something bigger. They can always up-engine it and stretch it. There is absolutely no reason to do a new design from scratch. If Europe neefs something then they should just stick to C-17, too. Airbus has been a disaster as a design house.

IIRC the entire plant is gone. (I think Relativity Space is in it now.) May as well start with a clean sheet. Give it to LM as they know how to build large military cargo aircraft.

They haven't built one since the 50 C-5Bs almost 40 years ago, and as far as designing a production aircraft goes that was just revising a design from almost 60 years ago. The only thing consistent about Lockheed in all that time is their ability to be years late and 300% over budget.

My first choice would be the C-17, preferably the C-17B, though I like the looks of the C17FE for support roles as well. Unfortunately worries that the CBO's studies that said you could shut down production and then restart it later for cheaper than keeping the line open were overly optimistic turned out to be true. At least with the F-22 shutdown the F-35 was being produced. There was nothing even remotely close to C-17 capability in production or in development anywhere in the west, and there still isn't. I'm having trouble thinking of a worse decision in the last 20 years.

My second would be for someone to make a second home for Antonov, and build westernized An-124s. Unlikely is putting it mildly, but given present circumstances now is the time when the idea could get some political traction and funding that would otherwise be virtually impossible. Thirty years ago would have been better.

Third, how about dusting off the KC-33 ATOCA design from Boieng? That involved raising the cockpit a little to create a uniform diameter cargo hold big enough to fit an M1 Abrams, and installing a upward tilting nose and ramp, with a total capacity of over 100 tonnes of cargo. The production line isn't dead yet, but will be really soon, so that may not be an option either. Actually, I think this is probably the best option to get something quickly. It could replace the KC-10, and supplement the C-5 fleet for carrying oversized cargo and heavy loads, even if it would be restricted to large runways.

Fourth, I actually like Nik's Thunderbird 2 suggestion. A blended wing body with a wide cargo area. But that is maybe for the generation after next.

 

[riggerrob]

" Nice, but the wings need to be more V-shaped. The outer part of the wings must produce downforce whereas the inner parts produce lift more to the front (for stability). To keep the downforce more behind and the lift more to the front, I would recommend a more V-shaped configuration as seen in most flying wings. ... "

Your proposed change is one possible solution.
However, deltas and low-aspect ratio flying wings tend to use reflexed airfoils to achieve the same sort of pitch stability. The aft half of the camber line is gently curved upwards to create a down-ward force on the trailing edge. This downward force counter-acts the nose-down trim created by installing the center-of-gravity forward of the center-of-lift. This balancing act is standard on the vast majority of self-stabilized (e.g. not fly-by-wire) planforms.
The delta's wing center-section is a convenient place to route structural members. The long center-section chord also improves lift-to-drag ratios. Ask Barnaby Wainfain how well that worked on his small, single-seater Facetmobile. We wonder how well that works at the larger Reynolds numbers of extra-large transports.

 

[BAROBA]

Hi all,
Thanks for the many replies, I have tried to incorporate as much as possible.
I had to do a lot of research-work to be able to implement the ideas.
I also noticed that my plane was a lot shorter then the 80 m of length that was allowed.
So I lengthened the plane and added canards in order to be able to change the CoG.
Now this design can carry a cylindrical shape that is 7 m in diameter and 50m long. ( The biggest cargo ever, if I am correct.)And it still has some room to spare...
The plane can do RoRo with regular cargo ( pallets, cars, trucks, tanks,...) But can only be loaded through the nose with extreme cargo. The rear-door is smaller then the nose-doors.
Controlsurfaces still have to be cut, but pretty much everything is there
I removed the fuselage and shaped the nose.( So now it has become a fuselage...)
Wheels also need to be added, two rows of 16 or so wheels should do it?

I thought about the Thunderbird 2 and its way to handle cargo, but that has been tried a few times and it never stuck... I think it is too dangerous... A pallet you can handle and through that you get an idea of how the mass is distributed in it. A car or truck you can secure to the floor and you know it will stay. A container can contain anything, you have no idea what is in it, if it is secured or not. The cargo inside of a container could be moving freely, you don't want some big mass sliding around in it. A container looks solid, but are thin-walled metal boxes that can hold some nasty surprises... Pretty much everything you don't want to be flying around with..

Feel free to comment,

Rob

 

[riggerrob]

Hi all,
Thanks for the many replies, I have tried to incorporate as much as possible.
I had to do a lot of research-work to be able to implement the ideas.
I also noticed that my plane was a lot shorter then the 80 m of length that was allowed.
So I lengthened the plane and added canards in order to be able to change the CoG.
Now this design can carry a cylindrical shape that is 7 m in diameter and 50m long. ( The biggest cargo ever, if I am correct.)And it still has some room to spare...
The plane can do RoRo with regular cargo ( pallets, cars, trucks, tanks,...) But can only be loaded through the nose with extreme cargo. The rear-door is smaller then the nose-doors.
Controlsurfaces still have to be cut, but pretty much everything is there
I removed the fuselage and shaped the nose.( So now it has become a fuselage...)
Wheels also need to be added, two rows of 16 or so wheels should do it?

I thought about the Thunderbird 2 and its way to handle cargo, but that has been tried a few times and it never stuck... I think it is too dangerous... A pallet you can handle and through that you get an idea of how the mass is distributed in it. A car or truck you can secure to the floor and you know it will stay. A container can contain anything, you have no idea what is in it, if it is secured or not. The cargo inside of a container could be moving freely, you don't want some big mass sliding around in it. A container looks solid, but are thin-walled metal boxes that can hold some nasty surprises... Pretty much everything you don't want to be flying around with..

Feel free to comment,

Rob

Several improvements.

May I suggest that the larger the canard, the worse imbalances it can tolerate?
Also, the farther forward the canard, the greater imbalances it can tolerate. IOW the farther the canard is from the main wings' center-of-lift, the greater imbalance it can tolerate.
Tandem wings (near equal size) are the most tolerant of poor balance.
When canard span equals main wing span, you will have a "Payen tandem wing." Some of Payen's designs were so bizarre (e.g. ambulance) that you wonder what he was smoking???????? Hah! Hah!

Your second set of sketches still have room remaining to move the canard farther forward until it is almost at the cockpit windows. Try to retain sideways visibility from the cockpit.

 

[Nicknick]

You need to keep in mind, that the aerodynamik center needs to be after the gravimetric center, so that you can't use equal sized wings for the canards.

 

[riggerrob]

You need to keep in mind, that the aerodynamik center needs to be after the gravimetric center, so that you can't use equal sized wings for the canards.

Yes, you can use equal-sized wings for canards.
You just need to install the center-of-gravity so far forward so that it loads the forward wing/canard more than the rear wing. This places the C. of G. forward of the mid-point between the centers-of-lift of the two wings.
This will also require installing the forward canard/wing at a steeper angle of attack to help it generate more lift and stall sooner than the rear wing. This premature (canard/front wing) stall helps stabilize the airplane in pitch by allowing the nose to drop during the early stages of a stall, before the rear wing loses lift.
If wings are equal-sized, they are referred to as tandem-wings (see Henri Mignet's Flying Fleas).

 

[riggerrob]

an alternative idea..

do we really need something as large as the An-225 again? It seems like a very niche aircraft.

I like the idea of the Kawasaki C-2. it has roughly a similar payload and range as the old Lockheed C-141 (and I guess Il-76?)
but done with two engines which could be more economical for air forces to operate.

can we scale this up a bit further? perhaps C-17 size?

Yes, Russian oligarchs still need an over-sized vehicle to quickly and quietly move their super-yachts away for banks or foreign gov'ts that might want to seize them.
Hah!
Hah!
Specialized semi-sinkable ships can carry multiple mega-yachts from one fashionable port to the next without fatiguing crew. I have seen them in Vancouver harbor. They can also transport a bewildering array of oil extraction equipment, tunneling machines, pre-cast bridge sections, etc.

 

[Nicknick]

Because a design challenge makes more fun with unusual approaches, I would like to propose a design which is a bit out of the box. My idea fairly conventional with some not so usual features. My idea that the resistance of very heavy plane will always be dominated by the induced drag and not by the parasitic drag. The design should therefor focus on maximum lift at take off and a lightweight structure, even if this will lead to higher parasitic drag. The amount of load largely depends on the take-off length on an ordinary runway, therefor the plane should be equipped with very strong turbo prop propulsion, (I added 6 propellers, so it will look automatically very powerfull ;-) .

Heavy load planes already do have something almost like stub wings at the bottom to house the landing gear (e.g. the A400m). In my design, these are more wider, so that they can create a ground effect. It is known, that these small wings helped a lot to lift the flying boats out of the water and Ecranoplanes used something quite similar for all of their lift. These stub wings are not effective in cruise flight, but they do help to get airborne and push the plane from the runway. On the other hand, these wings could also be used to produce downforce (by flaps, see the pics), so that the emergency breaking capabilities should improve. To switch between positive and negative lift, two different flap systems are needed, one aft for creating static pressure between the stub wings and the ground and one in the front to provide downforce when needed. If breaking is improved, the useful runway length can be increased which helps to take off with a heavier load. For take-off, the ground effect take-off flaps should extend at the beginning of the rotation, so that the maximum vertical acceleration can be achieved. By doing so, the rate of climb in the very early starting phase should be increased significantly, so that any nearby obstacles after the runway can be passed safely. Even if the additional ground effect of the stub wings is almost gone after reaching a flight high of about 5 m, the initial higher climb rate and steeper take off can make an important difference in the most critical part of the flight.

Since the stub wings take the load of the landing gear at hard landings, they can carry some of the main wing lift load during flight, so that a strut connection between them helps to reduce the root moment of the main wing and enables a higher wingspan (shorter take off, less induced drag). Struts can produce considerable amount of drag, but this depends very much on the angle, in a nearly rectangular angle to the main wing, as proposed here, this will be much lower than with the usual smaller angles.

My approach is not meant to be a high efficient, fast, long range or even a STOL aircraft, it is a proposal for a plane which should be capable of carrying super heavy loads from standard runways. Other than ordinary cargo planes, it is also not meant to be used as a regular freighter and should not fly in a regular schedule. The Antonov A225 made just few flights per year with a lot of preparation in between. The fuel cost and efficiency in this application will not be a major concern.

I made some drawings, which should demonstrate what it could look like.