The F-4E Phantom II: Simulating the 'Analog Storm' in X-Plane 12

[VSKYLABS Dev-Notes] issued 15th February 2026

Project development will soon be fully channeled to completing the F-4E cockpits (forward, aft), and to the completion of deep systems integration, including advanced featured and fail-modes throughout the F-4E operational envelope.

Here is a 'taste' of what's coming up in the development:

Both cockpits are being developed to be fully-functional in the initial release version. When engineering a high-fidelity F-4E simulation in X-Plane, which is above all a cutting edge aerodynamics and physics based flight simulator, 'Flying' the F-4E is 100% of the experience. We have no enemy engagement, no systems/warfare tactics. X-Plane provides a pure 'Test-Pilot' environment, in my perspective.

One of the most fascinating aspects of the above, is that it provides a rare opportunity to experience some of the real-world challenges of the F-4 Phantom II aircraft: flying the aircraft in the flight instructor seat, that is - operating and flying the aircraft from the back-seat. Forward visibility from the back-seat is one of the worst. Coupled with a sluggish, AoA sensitive aircraft - takeoff and landing from the back-seat becomes a true challenge, especially in heavy configurations. The VSKYLABS 'Test-Pilot' F-4E is being developed to provide full back-seat operations which will be deeply evaluated in full VR operations to provide the closest experience compared to the real-thing.

Another major development focus is channeled to 'aircraft (un)forgiveness' in the various phases of flight and operation modes. The F-4 Phantom II is not a forgiving aircraft. It is one of the last iconic, heavy, jet-fighter aircraft still flying, which has a 50's era aero-design and direct control interface to the pilot hands and feet. It has a very 'old' stability augmentation system, which is incomparable to the modern/late fly-by-wire aircraft. 

The VSKYLABS F-4E will have this Raw, 'Analog storm' embedded within, thanks to the advanced physics and delta-wing simulation capabilities of X-Plane 12.

In addition to aircraft performance, control handling characteristics and overall systems integration, the VSKYLABS F-4E will include a wide-set of failing modes and self-induced 'emergencies'.

Here are some examples of the simulated modes, to get into perspective:

• Replicating the authentic J79-GE-17 operating envelopes. Exceeding these and expect afterburner light-off, compressor stalls or flame-outs.
• Engines flame-out during abort takeoff in cold weather: In the F-4E, when operated from runways which are covered with excessive water, snow or slush, high-speed aborts may result in engine flame out, due to precipitation ingestion! The probability of such flame-out is highest when the throttles are chopped from full afterburner to IDLE at speeds above 100 knots. In case of double-flame out, normal braking, anti-skid protection and nose-gear steering will be lost. This behavior is fully simulated.
• Departures and Spins (including recovery).
• Authentic F-4E-Specific Zoom Climb - including afterburner blowout and all other relevant characteristics. We don't have active warfare in X-Plane, but we can fight the flight envelope!
• Authentic Single-Engine Performance and handling qualities. 
• (intentionally left blank...).
• And much, much more!

One of the greatest advantages of simulating a high-fidelity simulation of the F-4E in X-Plane 12 is that the 'Test-Pilot' can channel 100% of his attention to the core F-4E systems and to how to FLY it. The fact that we don't have a living warfare in X-Plane becomes an advantage especially for new pilots who wishes to have a close look-and-feel of the F-4E.

In the F-4 Phantom II, high Alpha regime, heavy takeoffs and practically any landing are not trivial and must be executed following deep understanding of the F-4 raw behavior. This is huge. For that reason VSKYLABS develops the F-4E with great attention to 'New Pilot Conversion' of all kinds of pilots in X-Plane. Under the 'Jet-fighter' skin, the F-4 Phantom II is 'Just' a fascinating aircraft that can provide endless hours of interaction and exploration. Not only for 'Jet-Fighter-Lovers'. 

I just completed one of the test flights in the VR environment and oh-boy...I can't wait sharing a few close-up screenshots of the evolving cockpit(s). The development threshold in this aspect has not reached the mature-phase that allows sharing these, but if all goes as expected, first close-up screenshots will be available for sharing within 2-3 weeks.

Stay tuned! 

Huss

VSKYLABS

Add-on Development Exponential Effort Curve - Explained!

[VSKYLABS Dev-Notes] issued 21st June 2025

"Why does it take months to release an aircraft add-on when it already looks complete in previews?" 

If you’ve ever followed a flight sim project, you’ve probably seen this:

“It looks done… but months go by and it’s still not released!??”

Here is a the truth, at least in VSKYLABS perspective:

Note: The following describes the general development aspects of VSKYLABS aircraft add-on for X-Plane flight simulator. However, the general idea remains the same in most, if not all flight simulator platforms such as MSFS 2020/2024, Aerofly FS and so forth.

So, in comprehensive aircraft add-on development, the early stages involve large, foundational steps of INITIAL modeling, flight dynamics foundations, systems framework...

The progress in these stages may be rapid and visible within a short period of time (short is a relative term as it can take days, weeks or months, depending on the aircraft).

However, as development advances beyond 85-90%, each remaining step becomes more detailed and nuanced, and the development 'gain' become smaller and far more time consuming. It involves multiple integrations, refinements, deep testing and so forth.

Sometimes, the 'hard to crack' and challenging components are intentionally left for this stage, and it takes time to...'crack'...

It's an exhausting phase of Exponential Effort Curve where each percent closer to completion demands exponentially more effort to complete.

To summarize:

In general, getting to ~85% takes 50% of the time. Getting the last 15%... takes the remaining 50% of the estimated time...

Depending on the aircraft and challenges, it can vary; sometimes getting to ~85% takes 20% of the time, and the last 15% takes the remaining 80%...

Huss-VSKYLABS