F-35C for Naval Aviation

[Jar_VFA-113]

All the Stingers are very amped for F-35C and would love to be able to land it on the ship, thanks in advance.

[Wizard_03]

I'd say chances are high since it says its already mentioned as a possibility in the FAQ. The PVI is intentionally similar across all three variants so no need to re-invent the wheel with the cockpit and systems, and CFD can be used for major Flight model adjustments, Same power plant. I'd be really interested to see how the F-35C handles in BFM, Both on its own and in comparison to the F-35A. I Suppose the finer details would be in how/and where the FCS logic differs from the CTOL version beyond the obvious like 7.5Gs instead of 9 but specifically the high AOA regime and slow speed handling. The gun pod would be interesting to work with as well. Seeing the effect the big wings have on range would be cool too. Advanced features like the magic carpet should make it very easy around the boat.

[draconus]

3 hours ago, Wizard_03 said:

CFD can be used for major Flight model adjustments

Due to different size and shape it has to be redone for the C.

[Wizard_03]

6 hours ago, draconus said:

Due to different size and shape it has to be redone for the C.

I don't imagine it's wildly different. In fact they have the exact same shape just in different sizes and proportions. Not like one is piper cub and the other is a B-52. 

Edited March 13 by Wizard_03

[draconus]

24 minutes ago, Wizard_03 said:

I don't imagine it's wildly different. In fact they have the exact same shape just in different sizes and proportions.

I expect much higher fidelity in DCS than just "it looks the same to me". No, they are not the exact same shape at all.

Edited March 13 by draconus

[Nealius]

Charlie model is going to be quite a bit different due to it's larger size affecting lift and wing loading. Who knows what else the Navy has in it for potentially more AoA capability than the other models. I wouldn't be surprised if they have different flight control systems logic. The Bravo certainly does for VSTOL modes. For the Navy variant we'd need PLM modeled as well.

[Wizard_03]

6 minutes ago, draconus said:

I expect much higher fidelity in DCS than just "it looks the same to me". No, they are not the exact same shape at all.

They have to be the same shape for LO characteristics to work on all three variants. That was kinda the whole point of designing one aircraft family instead of three discrete ones. I don't think it will be very hard for ED to plug in new dimensions for their CFD sim of it. 

[DummyCatz]

According to the public papers by Lockheed Martin, the aerodynamic differences in wing area and horizontal tail surface area among the versions, and the differences in basic stability and control power, are not trivial. Designing control laws for three versions at the same time, without standing up independent development teams, required creative approaches in order to meet program schedules. That's why a unified model-based, dynamic inversion approach using auto-generated code is chosen. This technique eliminates the need to linearize the aircraft system at specific flight conditions and develop extensive gain schedules, which is a time-consuming process in a more traditional FBW design. Instead, it allows designers to directly specify the desired aircraft response, accommodating the nonlinear dynamics of each variant. It adapts to aerodynamic, control surfaces and propulsion differences, through an onboard model (OBM) rather than requiring entirely separate control laws, ensuring similar flight characteristics and meeting program efficiency goals.

 

But still, here are some interesting unique FM differences:

The F-35C is less prone to deep stalls (same as those experienced by F-16) compared to the other variants, even in worst-case conditions. This is due to its larger horizontal tail, which contrasts with the STOVL variant’s higher susceptibility to deep stalls due to its smaller tail, and the CTOL variant’s weak deep stall potential only at extreme aft center of gravity (CG) positions with low fuel.

On the other hand the F-35C posed the most significant challenges in departure resistance (the ability to resist uncontrolled flight departures). For example, During a test maneuver, the aircraft experienced a rapid, uncommanded roll reversal due to adverse sideslip, aggravated by its unique features like aileron deflection, increased wing span, and the proximity of the wing and horizontal tail. This was addressed with control law (CLAW) modifications and updates to the aerodynamic onboard model (OBM). At around 0.75 Mach and near stall AOA, the F-35C exhibited poor sideslip control during maneuvers, leading to larger-than-desired sideslips. While control was maintained, CLAW updates and additional low-altitude testing were implemented to mitigate potential excessive loads.

The F-35C showed unique anomalies at lower altitudes (e.g., below 20,000 feet), where errors in Mach-dependent coefficients became more pronounced due to higher dynamic pressure and slower deceleration rates. This necessitated additional testing down to 7,000 feet MSL, unlike the CTOL and STOVL variants, which did not exhibit similar issues. The extra effort ensured the F-35C was cleared for unrestricted high AOA maneuvering at all altitudes.

Just some examples.

Fig. 1 of https://arc.aiaa.org/doi/10.2514/6.2018-3516 (F-35 Flight Control Law Design, Development and Verification)

Fig. 2 of https://arc.aiaa.org/doi/10.2514/5.9781624105678.0525.0574 (F-35 High Angle of Attack Flight Control Development and Flight Test Results)

Edited March 14 by DummyCatz

[SkateZilla]

On 3/13/2025 at 9:59 AM, Wizard_03 said:

I don't imagine it's wildly different. In fact they have the exact same shape just in different sizes and proportions. Not like one is piper cub and the other is a B-52. 

The A->C Shape is extremely different,
Wing Root, Wings, Flaps, Flaperons, Leading Edge, Trailing Edge, Horizontal Stabs, Vertical Stabs, Part of the Lower Fuselage, Entire Landing Gear System, Aft Fuselage, Hook Compartment, Upper Fuselage/Nose Area, AAR System, etc.

Although the A->C Avionics would be easy, the Flight Model would need to be a separate project.

The B is a different animal altogether, as there are systems in the B's avionics not present in the A or C.

 

 

Edited April 11 by SkateZilla

[EricJ]

I mean I'd fly a C version myself, but yeah understand the nuances of that ride...