Does Israel Have A Secret ‘Extended Range’ F-35I Adir Stealth Fighter?

Key Points and Summary: Speculation is growing that Israel has developed a specially modified F-35I Adir with an extended combat range, which enabled its recent long-range strikes on Iran without requiring extensive aerial refueling from its small tanker fleet.

-According to a June 14th report by Middle East Eye citing anonymous US officials, this extended range was achieved with US technical support by adding external drop tanks to the stealth fighter.

-While this modification solves a critical operational problem for Israel, it also raises complex questions about maintaining the F-35’s stealth characteristics, as any external stores can significantly increase an aircraft’s radar cross-section.

F-35I Adir: Did Israel Add More Range To This Stealth Fighter?

L’aéroporte Le Bourget, Paris – The Israeli Air Force (IAF) reportedly has only seven Boeing KC-707 Re’em air-to-air refueling aircraft in its entire fleet. Footage has already been posted online of one of these aircraft refueling an IAF F-16I over Syria’s Deir ez-Zor province while returning to Israel following a strike on Iran.

Military aircraft analysts comparing the capacity of these seven tanker aircraft with the number of fighters employed by the IAF on these strike missions have asserted that these seven would not be enough to sustain the Israeli operation. One answer, they say, is that the IAF possibly had support from the United States Air Force (USAF) in the form of additional air-to-air tankers available to assist the IAF.

However, the Trump Administration has denied any US involvement or support for the Israeli operation. Many speculate on an alternative explanation, one of which is that the F-35I Adir models supplied to Israel were modified with additional internal fuel tanks to provide the extended range necessary for a strike on Iran and then egress back to base without requiring refueling.

So, does Israel have some sort of extended range F-35I Adir the world is just discovering?

External Modifications of F-35I Adir? Lockheed Martin Told Us ‘No’

One of the potential answers to the IAF being able to keep operations running despite a small tanker complement would be to modify the F-35s involved in the deeper strike raids to support extended-range flights without the need for refueling.

However, here at the Paris Air Show, Lockheed Martin states they are not aware of any such changes to the Israeli aircraft and deferred questions on the issue to the IAF.

Modifications are said to have been made to the IAF F-35I, which in this Israeli-only version has the Hebrew nickname of “Adir,” to enable the aircraft to do just that. According to two US officials who spoke on condition of anonymity on June 14 to Middle East Eye, the aircraft achieved this extended range by adding more fuel.

“This is a game changer. Israel had our cooperation on this modification,” one of the US defense officials who spoke to the Middle East news outlet. Not just one, but both individuals confirmed that Israel modified their F-35Is with US technical support.

One of the officials declined to share details on how the F-35 was modified to augment its fuel load but cryptically added that an external adjustment to the aircraft was the key.

The second US official was more direct and admitted the increase in range was achieved by Israel attaching external drop tanks to the F-35s.

This modification was a solution to the one vexing problem that the US Administration had, which was how they could help Israel increase the operational range of the F-35.

However, the other half of the equation was how to do so without directly involving the US in the strike missions or providing direct, in-combat support.

F-35I Adir: Still Stealthy

Adding external tanks to a stealthy aircraft is also a sticky proposition. Any external stores will become radar reflectors, ruining the low radar cross-section (RCS) that the aircraft was designed to enjoy. It is that low RCS that enables it to penetrate enemy radar networks in the first place.

According to numerous specialists in low-observable aircraft design, the RCS makes adding a drop tank an exceedingly complicated proposition.

The F-35’s surface is composed of radar-absorbing materials, and any imperfections created in that surface or platform misalignments could compromise the RCS.

Even if the tanks were carried only during the beginning of a mission and then later jettisoned before reaching the range of Iran’s radar network, the underside of the aircraft would still have a small section exposed without radar absorbing material (RAM) to maintain stealth.

So far, the only stealthy aircraft that has completely resolved this problem is the F-22, which has specially developed stealthy external tanks to extend its range without increasing its radar cross-section (RCS). This was reported last year as one of a series of upgrades made to the aircraft.

About the Author:

Reuben F. Johnson is a survivor of the February 2022 Russian invasion of Ukraine and is an Expert on Foreign Military Affairs with the Fundacja im. Kazimierza Pułaskiego in Warsaw.  He has been a consultant to the Pentagon, several NATO governments, and the Australian government in the fields of defense technology and weapon systems design.  Over the past 30 years he has resided in and reported from Russia, Ukraine, Poland, Brazil, the People’s Republic of China and Australia.

The Best Tanks on Earth

AbramsX: The Tank the US Army Wants 

M1 Abrams: The Best Tank On Earth?

Challenger 3: The British Army’s New Super Tank