Design exercise: next generation carrier onboard delivery airplane for US Navy

riggerrob

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Design Challenge: Next Generation Carrier Onboard Delivery Airplane for the US Navy

This challenge was inspired by a real thread about difficulties introducing the CV-22 Osprey, tilt-rotor, Carrier Onboard Delivery variant to the US Navy.

What if the C-2 Greyhound fleet is due for retirement?
But C-2 and E-2 tooling is no longer available because hand-wavium worms have nibbled on the certified assembly jigs?
What if the CV-22 was judged unsuitable for the COD role?

It must be able to do all existing COD missions, plus inflight-refueling and a possible future Airborne Early Warning role.

The new airplane can have turbo-prop or turbo-fan engines.
It must be able to carry all the cargo items (e.g. complete engines) currently carried by C-2 and CV-22. Ideally even longer or wider items??????
Cargo size requirements also dictate the size of cargo ramps, cargo doors, hinged noses, etc. needed to quickly load or unload on a pitching ship's deck.
The next generation COD must be able to carry as many tons as existing CODs ... or more.
Range must equal or exceed existing CODs.
Cruise speed must be fast enough to refuel fast-jets.
It needs de-icing boots to fly through know-icing weather.
Emphasis on STOL performance to allow it to land slowly, at heavier weights. Catapult fittings and arrestor hooks will be standard.
Landing gear may be built in two distinct variants with high-pressure tires for carrier landings or a bolt-on set of low-pressure tires for a USMC mission to semi-prepared landing strips.
The cockpit needs to be pressurized (while refueling fast jets and cruising). But debate still rages as to whether it needs a full-pressurized cabin for carrying passengers. Some engineers have suggested a rigid, pressurized, cargo container for passengers, while others have suggested a simpler floor pallet with a soft, inflatable, pressure cabin (ala. Bigelow Aerospace module bolted to International Space Station).
A variety of quick-access panels will allow it to bolt-on the latest radios, chaff dispensers, flare launchers, electronic warfare gadgets, etc.
Wings must fold small enough to reduce foot-print when sleeping-over on the carrier deck.
Finally it must be less expensive to build and maintain than existing COD.

To sum things up, this third-generation COD must be able to fly all existing COD missions, plus refuel fast jets and maybe a future AEW role.
USMC are also asking for a STOL variant to supply forward operating bases.
 

Dynoman

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I would look at the Breguet 941 as a baseline aircraft or as part of the historical weight and performance fractions. Its performance was similar to the C-2, but offered some unique performance advantages, such as STOL and engine loss performance. Included is the carrier suitability proposal for the MD 188E (McDonnell Douglas' variant of the Breguet 941). Upper surface blowing concepts and designs such as the YC-14 and YC-15, as well as NASA's QSRA aircraft, might be considered.
 

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BB1984

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+1 to Dynoman

An additional consideration: the data on the Breguet 941 / Model 188 shows it could operate off the decks of Essex class carriers, which were very similar in length to the current generation of large amphibious ships. The amphibious shops are slower, though the 941/188 didn't need more the whole Essex deck . . . so a 941/188 also makes flight profiles like COD deliveries to amphibious ships and even amphibious ship to shore possible.

Note that I'm not suggesting literally an updated Breguet 941, but it shows that the STOL technology was there in the 1960s to make this work, so a modern version, with much more powerful twin engines and folding wings, should be do-able.

Ref alternate roles:
  • it's worth noting that the USMC currently uses the V-22 for air to air refueling, so the speed and altitude requirements aren't all that high for refueling aircraft up to and including the F-35 ( https://nationalinterest.org/blog/buzz/aerial-refueling-brings-v-22-osprey-whole-new-level-198974 ).
  • Higher altitudes in particular, and to a lessor extent, speed would be useful for an AWACS role, but unless the USMC is also a customer, it might make more sense to go unmanned for that, maybe an MQ-25 variant.

Note that politically, this also allows the Navy / Marines / Army to sneak a small STOL transport into the lineup against USAF opposition, so I like that factor too.
 

TomcatViP

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Honestly, Rocket should be the future. See how I have posted Gif of a simulated STOL starship size (and even heavier) rocket landing on sand. The exercise works also on a flatop deck (arrested) ;)

Imagine the advantages of having a bulky 150t cargo payload delivered in roughly 1 hr from CONU wherever you are meant to sail. That's not an evolution but a change in paradigm.

Edit:
1634136184327.gif
 

Archibald

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I red this thread first post, thought "Breguet 941"... and then posts 2 and 3 elated me.
I can confirm Breguet 941 took off in 120 m and landed in 200 m. And was considered as COD for Foch and Clem'.
Way to go, folks !
 

red admiral

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Potential more modern version of Br941 using distributed electric propulsion to give even greater wing blowing, increased safety,and eliminating the complex mechanical cross drive shafts? e.g. X-57 style but with a bigger wing as we're emphasising STOL rather than cruise performance.
 

Wyvern

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Maybe a tilt-wing for added STOL performance, where the whole wing pivots by a few degrees, similar to the wing on the F-8 Crusader. Blown flaps is another, option, that should give the same effect.

A large side-door and/or tail ramp for easy loading and unloading is of paramount importance. This would also give greater flexibility.
 

MadRat

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Why make it complicated with a tilt-wing? Palletized-loads using powered parachutes could get your loads parked in neat rows on a moving deck using JPALS. It's off the shelf. Delivery using powered parachute is proven reliable. And the method is agnostic to any specific offloading platform, so your delivery methods are flexible. You need much more capacity coming in than going out. Use a helicopter or Osprey to offload stuff to other locations to be picked up by tactical airlift command if it needs to get there fast.
 

helmutkohl

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what about a design that uses the coanda effect like the An-72 series or YC-14 but perhaps a bit smaller.
the An-72, if operating at short take off and landing distances, can probably do 400/600m, which should be enough for a US super carrier and thats without catapult.
 

UpForce

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I would look at the Breguet 941
Note that I'm not suggesting literally an updated Breguet 941, but it shows that the STOL technology was there in the 1960s to make this work, so a modern version, with much more powerful twin engines and folding wings, should be do-able.
I red this thread first post, thought "Breguet 941"
Potential more modern version of Br941 using distributed electric propulsion to give even greater wing blowing, increased safety,and eliminating the complex mechanical cross drive shafts?

Yeah, my first thought was the 941 as well, was attracted to that airframe from the first time I learned of it.

what about a design that uses the coanda effect

Could go well with "red admiral's" distributed propulsion.

Honestly, Rocket should be the future.

Rocket logistics, wild. Don't quite know how and whether rockets could be turned around from a carrier (yet) but no harm in trying to figure these things out. Hydrogen economy is growing and all. This could be piloted with time sensitive missions.
 

red admiral

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what about a design that uses the coanda effect like the An-72 series or YC-14 but perhaps a bit smaller.
Its a pretty similar approach to the externally blown wing on the Br941. Ideally you want to blow the entire span to maximise lift, thats where more smaller distributed propellors come in.

From looking at previous aircraft you can probably reduce stall speed enough with this approach that you're actually limited by control power as your aerodynamic control effectiveness drops off with reducing speed. Pretty sure we'd want to avoid puffer jets for this.
 

Dynoman

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The electric propulsion idea is interesting, but the power densities required to fly a cargo aircraft hundreds of miles is not a near term reality. Distributed power systems using turboelectric generators are being explored by NASA and others (Rolls Royce/Airbus, Honeywell, etc.), but these only produces approximately 1 to 2.5 MWh of power. A cargo aircraft would need in the realm of 40-60 MWh. Jet fuel is about 50 times more energy dense than batteries. For an aircraft design that is projected in the next 10-20 years I would think a turbofan or turboprop design would be more likely. Tilt wing (eg. XC-142) or tilt prop (eg. CV-22) would be ideal for small deck ships, however a STOL aircraft that doesn't use powered lift to achieve a take off or landing can delivery more payload for a given weight than the VTOL equivalent design. For example, a Grumman C-2 has about 32% of its gross weight dedicated to useful load and a Breguet 941 has about 51%. A CV-22 has about 20%Wg to dedicate to useful load.
 

TomcatViP

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But why would you use an EV aircraft, one that has a very minimal payload fraction, for cargo resupply mission... If you then need to use the aircraft carrier electrical power for your flight back, something that will be already in short supply as all projection suggests?
RE-supply is the mission. Not DEplete.

On the rocket side, you have at least 1500/2000 embarked sailors and airmen that will produce a considerable amount of processed waste every day... A simple Digester can convert those waste into methane that can then be boosted with on-site production of H2 (hint, there should be water all around if your nav was not messed up)...

That's where the Rocket COD pimp up the concept a bit (through...).
 
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Silencer1

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I think, we could add one minor addition to the "Future COD" requirements: not only "onboard", but "off-board" capabilities. The vehicle, that could easily used for transporting any stuff from the carrier: malfunction equipment, wounded or ill persons or just a company of people. And all this under regular procedures, using the fuel and infrastructures already located on aircraft-carrier.
 

Archibald

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Tilt wing (eg. XC-142) or tilt prop (eg. CV-22)

-Canadair CL-84 tilted the entire wing, with the engines and props attached.
-XV-15 & V-22 tilts "only" the whole engine nacelle, wing doesn't move anymore.
-And now Bell has a prototype which only tilts the propellers - wing and engines remain fixed.

I really like those variations on the same idea, over time.
 

jstar

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Tilt wing (eg. XC-142) or tilt prop (eg. CV-22)

-Canadair CL-84 tilted the entire wing, with the engines and props attached.
-XV-15 & V-22 tilts "only" the whole engine nacelle, wing doesn't move anymore.
-And now Bell has a prototype which only tilts the propellers - wing and engines remain fixed.

I really like those variations on the same idea, over time.
It's a full circle thing...Bell's XV-3, their first tilt rotor project, also tilted only the rotors.
 

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red admiral

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I wouldn't go with electrically powered. Probably twin turbogenerator mounted at mid wing / wing tip nacelles and then electric motors with props distributed along the wing. Still turning kerosene (or SAFs) into propulsive power but power transfer is electric rather than mechanical. Bit of an efficiency hit there in power transfer but probable overall net gain for this application. Want something like 5-10 MW overall which should be well within reach in the next 10 years - today it just forces a need for increased number of turbogenerators.
 

UpForce

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Probably twin turbogenerator mounted at mid wing / wing tip nacelles and then electric motors with props distributed along the wing. Still turning kerosene (or SAFs) into propulsive power but power transfer is electric rather than mechanical.

Was thinking along these lines myself, based on the discussion so far.
 

TomS

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The simpler and more robust the platform the better.
A stol two engined fixed wing plane is the way to go.

To an extent. The IRL decision to adopt the V-22 wasn't just about fashion. It was also about the ability to support operations from the big-deck amphibs, especially in their Lightning Carrier role. So STOVL over STOL has potential value.
 

helmutkohl

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im surprised no one has brought this up yet as a C-2 alternative
Osprey's larger, voluptuous cousin
mfSPK9x.jpg
 

UpForce

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Potential more modern version of Br941 using distributed electric propulsion to give even greater wing blowing, increased safety,and eliminating the complex mechanical cross drive shafts? e.g. X-57 style but with a bigger wing as we're emphasising STOL rather than cruise performance.
I wouldn't go with electrically powered. Probably twin turbogenerator mounted at mid wing / wing tip nacelles and then electric motors with props distributed along the wing. Still turning kerosene (or SAFs) into propulsive power but power transfer is electric rather than mechanical. Bit of an efficiency hit there in power transfer but probable overall net gain for this application. Want something like 5-10 MW overall which should be well within reach in the next 10 years - today it just forces a need for increased number of turbogenerators.

I thought about this while reading a recent article on Flight about "Odys Aviation"; the outfit seems to be quite "tech-broey" (and small, currently at only 12 people) but their idea seems to be not entirely unlike what we've been discussing here.



Pilar Wolfsteller for Flight said:
... Odys is looking to build a craft that can fly at high altitudes and will connect regions hundreds of miles apart. ...

... The company’s website reveals few details about its concept, but its renderings depict a unique, futuristic blown-wing design with a small cabin (that seats nine, Dorris says) and 16 propellers. ...

...“Tilting mechanisms have some great upside but also some potential difficulties,” Dorris says. “So we have built the vertical take-off and landing system based on a high-lift flap.”

“We extend the flaps, just like on any other commercial aircraft. Ours are slightly bigger, and extend at a greater angle. That’s what we use to deflect the airflow from our propellers vertically down, generating lift.” ...

View: https://www.youtube.com/watch?v=b-nPXJ9JsxY
 

red admiral

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Nah, that company's concept is far more unrealistic than what I was talking about

How do they get any control? How do they transition from vertical to horizontal flight?
 

helmutkohl

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on a related note, there's news that the USN is considering the use of drones for onboard delivery.
i guess rather than one larger cargo plane..
smaller amount of items being delivered on more drones?
 

UpForce

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on a related note, there's news that the USN is considering the use of drones for onboard delivery.
i guess rather than one larger cargo plane..
smaller amount of items being delivered on more drones?

Well, it's at least logical to consider this as the opportunity so clearly presents itself. Potentially more flexible (depending on type it doesn't necessarily have to land on a carrier at all but perhaps on a support ship) and making it somewhat harder for adversaries to surveil and disrupt logistics in general. Stealth, though, may not matter as much these days since merely not emitting EM radiation does much less to hide a strike group than in Cold War days. From "loyal wingman" to "trusty freighter"?
 

helmutkohl

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on a related note, how far are these type of aircraft are supposed to fly?
I was under the impression that they ferry between the land base to the ship that's nearby. not so much flying when the ships are in the middle of the ocean.
 

VTOLicious

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One key requirement is to transport the F135 power module, in one piece ;) ...CMV-22B has a range up to 1150 nm.
 

TomcatViP

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Another view of what could be a Rocket COD (the SIM is not that of a carrier landing) - notice the gentle vertical acceleration values (yes yes, in earth G). The 250t (metric) rocket needs only less than 600ft to land without the help of any arresting wire (the lines are graduations (-50m, 0, +50, 100, 150) :

Ship&_Earth_a_Graph4.gif
 

helmutkohl

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a somewhat related question
was there any interest in France to acquire the C-2 greyhound for either its Charles De Gaulle or future carriers?
Since it already operates the E-2, I am surprised they don't also go for the C-2.
 

TomcatViP

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Interest, yes. Budget, hell no ;)
(coming from a country that can't even buy a dozen of used Chinook for its army engaged in African deserts, no surprise).
 
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