US Navy Multi-engine Multi-Crewed Carrier Capable Training Aircraft - T-44 Replacement

[aim9xray]

The problem is that design requirements are not always coordinated inside customer organizations and stovepipes...

 

[Dynoman]

Aim9xray, that illustration brings to mind the debacle that was TFX. The Navy and Air Force were tasked with developing one airframe that would support naval fighter operations to replace the Navy's F-4 Phantom while the Air Force concentrated on requirements for strike/interdiction to replace the F-105. Ultimately, the Navy's F-111B program was cancelled as its overweight and underpowered airframe would not fulfill the Navy's mission. Similar issues with the DoD and NASA on the Space Shuttle program for winged vs lifting body designs.

The twin multiengine naval trainer concept presented here was really a 'what if' the Navy added a carrier landing and launch capability to the replacement program of the T-44 Pegasus. Nothing off-the-shelf would be suitable. In my opinion the new Valor would be the closest concept for tilt-wing training, but it still wouldn't help the fixed wing turboprop community flying carrier capable E-2s and C-2s. A tilt wing aircraft that could transition to horizontal landing and takeoff would be ideal, such as the Chana CTW 409.

 

[Dynoman]

XV-15 Navy trials on USS Tripoli. Would have been neat to have seen a trainer tiltwing variant emerge from the XV-15. Of course opportunities existed with the AW609 since the early 80's.

 

[TomS]

Of course opportunities existed with the AW609 since the early 80's.

? BA609 didn't even kick off until the late 1990s.

 

[Dynoman]

Thank you, I meant to say existed with the Bell design since the 1980s. Trials for the XV-15 from the carrier was in 1983.

 

[Stingray 320]

There is NO requirement for the ME trainer to land in the boat, as the vast majority of advanced students are for P8/C130/E6 and V22 (who get their boat quals at the FRS. The E2/C2 student throughput is small in comparison and they get carrier qualed in the T-45 anyways. We should be looking at a new KA 200 or what the Brit’s did with the Phenom 300’s (or something similar like the Citation Mustang) to get ME training accomplished.

 

[Dynoman]

There is NO requirement for the ME trainer to land in the boat, as the vast majority of advanced students are for P8/C130/E6 and V22 (who get their boat quals at the FRS.

You are correct. There are no real requirements for a carrier capable T-44 replacement. The KA is the most economical design that meets the Navy's req.'s today. The training at FRS is specific to the airframe in which aviators will fly. The common denominator is a ME aircraft that provides asymmetrical thrust for training and with pressurization to climb to cruise altitude for long leg flights.

Although there is not a requirement for a carrier capable multi-engine training aircraft this thread is used to address the design requirements and concept of such an aircraft.

There are other designs (namely existing corporate aircraft) that could potentially meet the performance requirements, but again for small turboprops, they all lack cabin pressurization, and for the turbine designs, they are all more expensive to operate.

The design effort could be to simply design a pressurized hull within an existing turboprop airframe. But that would be too boring. A design similar to the Embraer CBA 123 Vector, which is a unique design that marries pressurized cabin with fuselage pylon mounted engines, however the engine spacing would reduce the effect of asymmetrical thrust.

The fun in the design effort would be looking at how such a design (similar to a T-44) could operate around the boat. To expand on the concept other ideas for such a design could be for an economical ship launched maritime surveillance aircraft or as a ship to shore liaison aircraft, or even a communications relay with loiter capability, similar to an RC-12. Again, all for fun and no specified requirement.

 

[TomcatViP]

It appeared to me reading the above analysis that we are probably looking at the problem the wrong way: searching for an existing off the shelf Turboprop a/c.

What about rebuilding an existing design to Navy requirements at a minimal expenses?

I am basing that essay on the Pilatus PC12.

Despite being a single engine design, it's an efficient short field cruiser with a pressurized cabin (rare!). It then suits well many parameters of the mission but, obviously, the twin engines aspect of the training.

Let's add a twin set of podded EV engines, one per wing. Let's connect them to the turbine that will run as a generator through a minimal battery. The battery will be sized to sustain all the carrier approach part of the mission only (probably 30 to 60 min of flight time) to minimize weight addition.
Then let's add a set of folding Propellers to each of the E-engines and a manually installed socket to reduce the drag when wing's engines are not required.

During the carrier approach training, all 3 engines are running. The nose turbine is ran at full throttle to generate electricity but its thrust is managed through the Propeller pitch. This creates a variable drag to simulate various interesting scenario for the trainee and increases safetyness with the possibility to quickly add power on the fuselage axis for a turnaround.

Wing podded engines are run like in any twin engine a/c.

Using a PC12 will ease certification of a de-rated turbine (if my memory stands right it has been already done by Pilatus). Pilatus are also already in the forces, greatly reducing the logistical footprint of the new design.

I realize a sketch would be welcome. But I guess you get the idea.

 

[Dynoman]

Here's a quick concept sketch. I made a second drawing indicating a gas generator for electric power in place of the PC-12's PT-6 engine. However, the initial version would likely have to retain the engine due to the lack of EV efficiencies required for aircraft endurance.

 

[TomcatViP]

@Dynoman : This is exactly what I had in mind. Congrats for the graceful and prompt execution!

With the nose mounted engine, wing pods do not have to provide full power like in any twin engines. Here the focus is training and their size, notably that of their Propellers is only dimensioned to achieve mission goals (replicating the twin engine experience, even by applying differencial pitch on each wing engines in order to only simulate the adverse yaw effects). Hence it is possible to lower the drag and minimize wing flows interaction with a more streamlined setting closer to the wing surface with a reduced diameter Propeller disc area to compensate for the lost ground clearance.

 

[Dynoman]

Here's a systems sketch of the concept, including the three YASA motor configuration used in the Spirit of Innovation aircraft:

 

[Dynoman]

Honeywell's HGT1700 turboelectric generator and battery cell containment packs:

 

[Dynoman]

In the previous design I placed the battery packs in the fuselage, however, the engine nacelles may be able to contain the cells in a narrow aerodynamic fairing. Pod mounting the cells would help in reducing the fire hazard and cooling requirements in the cabin and reduce the power distribution wiring. However, the mass distribution to the wings would reduce the roll rate and require the wing roots to be strengthened.

 

[TomcatViP]

Don't worry, the PC12 is not yet certified for Carrier arrested landing. It would need a new beefed up spar anyway.
IMOHO, the duplication of electrical power generation is ill-advised since it will add complexity and certification headaches.
Adding a simple battery that can be charged during the cruise portion of the flight is more easy. The Batteries pack can be placed inside the baggage compartment and not interacts with the passengers cabin while already meeting regulations and weight distribution.

It's all about minimizing the total cost and weight increase for Pilatus. Otherwise, if the acquisition cost doubles and structural integration requires double the certification, the Navy will do otherwise.

 

[Dynoman]

Additional component weight and balance:

 

[Robert139]

Has any of y'all been through the training pipeline for any of the multiengine aircraft (other than jets) that are in the NAVY/USMC/USCG fleet?

The ideal replacement for the T-44 is........another King Air.

 

[RavenOne]

So it be known as the T-54 now...

Textron Aviation Special Missions Beechcraft King Air 260 chosen as new U.S. Navy Multi-Engine Training System (METS)

Textron Aviation today announced it has been awarded the Multi-Engine Training System (METS) contract by Naval Air Systems Command (NAVAIR) through a full and open competition.

media.txtav.com

 

[Dynoman]

Since Textron owns both Beechcraft and Cessna, there would not have been any competition for the King Air from Cessna. Even with their new Sky Courier or from any of the other Cessna products. I'm curious to see who were the other proposals from and with what aircraft. I can only imagine that most were light turbojet twins, such as the Phenom 100. Something similar to an Embraer CBA-123 would have been interesting.

 

[fightingirish]

So it be known as the T-54 now...

Textron Aviation Special Missions Beechcraft King Air 260 chosen as new U.S. Navy Multi-Engine Training System (METS)

Textron Aviation today announced it has been awarded the Multi-Engine Training System (METS) contract by Naval Air Systems Command (NAVAIR) through a full and open competition.

media.txtav.com

See also the thread 'US Navy picks Textron: Beechcraft King Air 260 Multi Engine Trainer System' https://www.secretprojects.co.uk/th...ng-air-260-multi-engine-trainer-system.40921/

 

[Dynoman]

See also the thread

Thank you! It's a shame no other competitors in the field. With competition comes innovation.

 

[RavenOne]

So it be known as the T-54 now...

Textron Aviation Special Missions Beechcraft King Air 260 chosen as new U.S. Navy Multi-Engine Training System (METS)

Textron Aviation today announced it has been awarded the Multi-Engine Training System (METS) contract by Naval Air Systems Command (NAVAIR) through a full and open competition.

media.txtav.com

See also the thread 'US Navy picks Textron: Beechcraft King Air 260 Multi Engine Trainer System' https://www.secretprojects.co.uk/th...ng-air-260-multi-engine-trainer-system.40921/

that was the thread I started lol

cheers

 

[Scott Kenny]

It's really hard to argue against a King Air as a twin engine trainer...

 

[RavenOne]

First two T-54 have been delivered

Textron Aviation Special Missions begins deliveries of U.S. Navy Beechcraft King Air 260 Multi-Engine Training System (METS) Aircraft

Textron Aviation today announced it delivered the first two of up to 64 Multi-Engine Training System (METS) Beechcraft King Air 260 aircraft contracted by Naval Air Systems Command (NAVAIR) on January 25, 2023, following a full and open competition.

media.txtav.com

Cheers