Rafael I-Derby ER - Improved Precision AND Range

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Suggestion No.78

G’day lads. I want to suggest an improved version of the current Derby, featuring an upgraded seeker, newer systems and a dual pulse motor, all of which is found on the I-Derby ER :)

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Description:

Spoiler

The Derby is an Active Radar Homing (ARH) missile, first shown in the early 2000’s. It is based of the Python, but barely has anything that uses components of it (despite rumors). The I-Derby is the same as the Derby, however features improved ECCM capabilities, making it harder to distract with countermeasures. Due to it being the same as the normal Derby, it has around 50km range when air launched, and 20km if ground launched. The extended range version of the I-Derby, which was shown later, is known as the I-Derby ER. As the name says, it has improved range, giving it 100km of range when air launched or 40km if ground launched. This range is achieved with a dual pulse motor, which the other Derby variants did not have.

The Derby missiles are sometimes also known under a “Mk.” name, like the Derby being Mk.I, I-Derby being Mk.II and I-Derby ER being Mk.III, although that designation is kinda rare

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History:

Spoiler

The project for the Derby began in the 1980s, with development efforts gaining momentum after South Africa provided funding and joined the program. By the 1990s, the Derby had undergone extensive flight testing, including trials on Israeli F-16 fighters. The missile was officially acknowledged in 1998, though reports suggest it had been in development for at least a decade before its public reveal. Rafael sought to create an alternative to export BVR missiles. By integrating FnF technology and active radar tech inside of it, the missile was made. While the Derby was inspired from the Python 4, it didn’t use as much tech from it as some rumors claim. The Derby became operational in the early 2000s and was later exported to multiple countries, including Brazil, India, and Chile, where it was integrated into various fighter platforms and air defense systems.

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^ Brazilian F-5EM carrying Derby

During Aero India 2015, a new missile was shown, which was the I-Derby. The improvement of it was it’s seeker, which had improved countermeasure resistance, including better ECCM and computing systems. On the same year, Rafael also said that an extended range version was planned, which was the I-Derby ER.

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The ER achieved operational status in 2018, where it was then sent off to the export market. The ground based version had some tests done during 2021 with relative success. From what I can see, the visual difference between both missiles is that the I-Derby is grey, meanwhile the I-Derby ER is light blue. Additionally, the I-Derby ER does not have the same rolling fins anymore as found on the 2 previous Derby variants (only exception I can find is on one/few exhibition/s). The rolling fins it has now are smaller and swept, instead of being straight

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^ This image was originally on the normal I-Derby brochure, but is also found on the ER version

Specifications:

Spoiler

The I-Derby ER is the same as the I-Derby with its seeker, where compared to the normal Derby it has a better seeker, so it gets less distracted by countermeasures. It has a weight of 122kg, a length of 362cm, wingspan of 64cm and a diameter of 16cm. Of course the main upgrade is its newer, dual pulse motor, which can make it go up to 100km if launched from the front from an aircraft, 70km if turning right or left and 40km if it does a full 180. According to Marvin Engineering, who makes LAU rails, Derby’s can be carried on any platform which has either LAU-127, 128 or 129

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Screenshot 2025-05-23 162012

Sources:

Spoiler

https://www.rafael.co.il/wp-content/uploads/2024/09/i-derby-er-air-to-air-and-surface-to-air-missile.pdf

I Derby ER | PDF | Fighter Aircraft | Aviation

https://marvineng.com/wp-content/uploads/sites/5/2018/01/LAU-127_128_129-Launcher.pdf

Derby

https://www.edrmagazine.eu/rafael-marks-another-milestone-in-the-development-of-the-i-derby-er-air-to-air-missile

Derby | Weaponsystems.net

https://defense-update.com/20150220_i-derby.html

You can also find my I-Derby variant suggestion here:

Thanks a lot for reading! If you have any extra information, then feel free to share them in the replies! As always, have a good day :)

6 Likes

Big +1 from me, as notably although this missile is quite modern, it’s still quite short ranged compared to missiles developed much earlier than it.
For War Thunder however, its range is more akin to what the Aim-120C-5 is IRL as I’ve heard, and the seeker capabilities would be minimal seeing as how gaijin

1 Like

+1 would love to see it on current aircraft like the Kfir C.10 Blk 60 as well as future aircraft to come like the F-16I

Idk if any upgraded F-5E operators used the I-Derby ER but it would be cool to see it on something like the F-5EM, Tiger III+ or the TH

:D

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Unfortunately not, as of now they’ve only used the regular derby, and I’ve yet to see evidence of them using the I-Derby, let alone the I-Derby ER. That doesn’t mean it couldn’t change someday, as Brazil, Thailand, and Chile could upgrade them in the future. (but I see them such as unlikely given the aircraft they’re using now. It’s more likely a even later export package gets developed including it and a newer radar before those countries decide to upgrade them ever further, but man what’d I give to see an F-5E Tiger IV lmao)

From what ive found the F-5E tiger IV had a new cockpit and the APG-66 radar. I dont know a lot about the Tiger IV but I think itd make a good squadron vehicle or maybe even foldered with the F-5E if more info is obtained about it.

Me personally im more of a F-5N / F-5N+ fan and im thinking of writing a suggestion for it when i have the time to do so :D

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I mainly meant a Tiger IV upgrade in the sense of a successor upgrade to the IAI Tiger III upgrade, not the US Tiger IV upgrade for aggressor aircraft.

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I cant find much about the IAI Tiger IV, is it different than the III+ in any meaningful way? Info would be appreciated.

Ty in advance :D

It doesn’t exist (yet), which is why I said

Essentially it could exist someday if the countries using these aircraft want to continue using and improving them. They could very easily put the Kfir C.10 Block 60’s radar in one, give it Python 5s and I-Derby ERs, add the capability to carry additional AAMs, update precision strike capabilities, and upgrade it’s defensive capabilities with MAWS and additional CM dispensers/EW equipment. It’s unlikely given how dated the airframe already is, but it’s a cost effective aircraft that can stay relevant if they want an upgrade like that. However Chile, Thailand, and Brazil both have more modern aircraft now and it’s unlikely they’ll modernize their F-5s even further then they already have. If anything they’ll be relegated to an aggressor or trainer role if they continue to fly for them. Perhaps other countries still using the F-5 may do such instead, dunno, but what I would give to see the I-Derby ER on an F-5, hopefully someday it’ll happen.

+1 But knowing them they wont give it to kfir block 60

2 Likes