Aerodynamic modification kit

[Swayer]

The AMK would be something really dominating to have, even though I just want to bring this up to discussion.

It increases the AOA by 45% , roll rates by 100% and it allows for a tighter turn radius. Aswell as low speed handling.

Not only is it a potent kit in the A/A role but in the A/G role aswell which the EF/Typhoon is said to not be great at.

[F-2]

It’s unclear if anyone has bought it yet. Would sure be cool though.

[Swayer]

5 hours ago, F-2 said:

It’s unclear if anyone has bought it yet. Would sure be cool though.

I think they will add it to all production aircraft

[Spurts]

No one has ordered it, not even the country that developed it.

[Swayer]

8 hours ago, Spurts said:

No one has ordered it, not even the country that developed it.

The Eurofighter works well without it but more bang for your buck 

[whiteladder]

I think the amount of retesting that would be involved with fitting the kit would put most off.

[JOYFUL_CLOVR]

It would be cool and an amazing asset, but remember that the module is being based off the early iteration of the Typhoon, not the modern one and without modern updates wouldn't necessarily work. 

[Hummingbird]

On 1/27/2022 at 11:56 AM, whiteladder said:

I think the amount of retesting that would be involved with fitting the kit would put most off.

It has been extensively tested by airbus, so that's not really the issue I think. The real issue is more likely a question of "is it worth it?". The EF is already very maneuverable, so it's up to the customer to decide wether a higher AoA capability & roll rate at low speeds is essential. I believe it's the same reason we haven't yet seen anyone procure the thrust vectoring upgrade for the EuroJet engine either.

 

But let's see, Germany might just get it for their upcoming jets.

Edited January 30, 2022 by Hummingbird

[whiteladder]

The testing that airbus have done is a small part of the process, when the envelope of the airframe is changed so dramatically you have go back a retest a whole bunch of things for example munition separation. One of the things that has delayed a number of Raf Typhoon projects is the lack of development aircraft to run the test program.

[F-2]

I believe the Eurofighter is not the best bellow 10000 feet, that’s where they tend to struggle with the Rafale and F-16a. Sorta similar to the F-15, but unlike the F-15 the Typhoon is technically a multirole that might need the extra mobility down low, just apparently not enough to pay for it.

[Hummingbird]

On 1/30/2022 at 6:22 PM, F-2 said:

I believe the Eurofighter is not the best bellow 10000 feet, that’s where they tend to struggle with the Rafale and F-16a. Sorta similar to the F-15, but unlike the F-15 the Typhoon is technically a multirole that might need the extra mobility down low, just apparently not enough to pay for it.

You're basing that belief on your interpretation of a single article. The EF doesn't struggle below 10 kft,  the F-16 & Rafale face the exact same "problem", i.e. all three got so much performance that down in the thicker air the squishy meatbag in the cockpit is the limiting factor, not the aircraft. In other words pilots in these three are going to find it extremely difficult and uncomfortable to fight each other below 10 kft, as all three aircraft will sustain 9 G's with ease down there.

However as you go higher and the air gets thinner, and thus less G's can be sustained, that's when you start to see aircraft performance making a big difference.

Edited March 30, 2022 by Hummingbird

[F-2]

1 hour ago, Hummingbird said:

You're basing that belief on your interpretation of a single article. The EF doesn't struggle below 10 kft,  the F-16 & Rafale face the exact same "problem", i.e. all three got so much performance that down in the thicker air the squishy meatbag in the cockpit is the limiting factor, not the aircraft. In other words pilots in these three are going to find it extremely difficult and uncomfortable to fight each other below 10 kft, as all three aircraft will sustain 9 G's with ease down there.

However as you go higher and the air gets thinner, and thus less G's can be sustained, that's when you start to see aircraft performance making a big difference.

 

https://www.flightglobal.com/eurofighter-new-aerodynamics-set-for-2014-test-flight/113606.article
 

Quote

Eurofighter will by year-end make is final proof-of-concept test flight on an aerodynamic modification kit that promises to improve the combat aircraft’s subsonic turn rate by 15%.

Adding leading edge root extensions and extended trailing edge flaps, and reshaping the side-of-cockpit ILS antennae covers as 70° delta strakes should improve the aircraft’s agility for close-quarters combat.
 

Laurie Hilditch, head of future capabilities at Eurofighter, says the modification kit should give the aircraft the sort of “knife-fight in a phone box” turning capability enjoyed by rivals such as Boeing’s F/A-18E/F or the Lockheed Martin F-16, without sacrificing the transonic and supersonic high-energy agility inherent to its delta wing-canard configuration.

The 1986 mock up had LERX very similar to the AMK. These were presumably eliminated to optimize supersonic turning as the AMK slightly effects this. That was a perfectly reasonable design decision, that’s the Eurofighter’s bread and butter along with thrust. With that it has a substantial advantage over any fourth gen aircraft. If you get down and dirty your tossing that away for at best parity. Remember it’s a Typhoon not a Raptor with the Ram rubbed off.

 

[Hummingbird]

Again you're interpreting things incorrectly.

"“knife-fight in a phone box” turning capability" --->This refers to low speed high AoA one circle fighting, which is all the AMK kit is going to help with, not sustained turn rate. In short it's all about providing a higher nose pointing ability (i.e. higher AoA limit) at low speed, which apparently most operators of the EF don't find necessary as the EF maintains a general advantage in ITR & esp. STR over most other fighters.

 

Also keep this in mind: The lower the wing loading, the lower the lift coefficient, and thus AoA, is needed in order to generate the necessary lift for a specific load factor -> this is the general principle the EF lives on. In other words the EF can generate the same ITR at a lower AoA than many other fighters.

 

Edited March 31, 2022 by Hummingbird

[Deano87]

Apparently It also helps reduce heavy weight landing speeds as well...

Interesting modification.

[Hummingbird]

4 hours ago, Deano87 said:

Apparently It also helps reduce heavy weight landing speeds as well...

Interesting modification.

 

Yes, that would be from the ability to employ the slightly enlarged flaperons on landing.

[Deano87]

47 minutes ago, Hummingbird said:

 

Yes, that would be from the ability to employ the slightly enlarged flaperons on landing.

I believe it's mostly from the improved vortex generation caused by the LEX and cockpit-side strake mod that increase overall lift at landing AoA.

[Rav]

22 hours ago, Hummingbird said:

Also keep this in mind: The lower the wing loading, the lower the lift coefficient, and thus AoA, is needed in order to generate the necessary lift for a specific load factor -> this is the general principle the EF lives on. In other words the EF can generate the same ITR at a lower AoA than many other fighters.

Indeed, the EF has the lowest wing loading at MTOW and 50% load of all modern western fighters. In fact the only fighter that matches both the EFs WL and TTW at 50% load is the Su-57.

Edited April 1, 2022 by Rav

[Lurker]

I assume that this kit has some tradeoffs, such as higher drag at higher speeds? 

[Deano87]

I doubt it has any major negative effects, it's such a small change as far as sq.ft or frontal area, it's more about better creation and control of the vortices that shed off the LERX and ILS strakes and how that affects the aerodynamic performance of the wing and the pitch/roll authority of the flaperons. And that only really comes into effect once the jet has some AoA, at high speed I imagine any extra drag would be negledable.

Edited April 1, 2022 by Deano87

[Hummingbird]

19 hours ago, Deano87 said:

I believe it's mostly from the improved vortex generation caused by the LEX and cockpit-side strake mod that increase overall lift at landing AoA.

 

It's a combination of the increase in AoA the LERX permits, which in turn allows the use of the enlarged flaperons (applying TE flaps decreases critical AoA) for a sizeable increase in lift during landing without compromising over the nose visibility.

[Spectre11]

The purpose of the enlarged flaperons is to counteract the pressure point shift due to the LEX and delta strakes. Increased roll authority is a partial byproduct of the flaperons increased size, as well as the energised airflow over the wings. The flaperons themself do not lower the approach speed as the flaperons are not used as flaps to assist during takeoff and landing, as is the case with tailed designs. The main point of the AMK is to increase the stability at higher AoAs and to address the deficiencies of the basic design in that area. The FCS imposed AoA limit currently limits the max lift, the airframe is capable of generating more lift, but the current limit prevents this and is as such limiting ITR performance, in addition to nose pointing authority and low speed maneuverability.

[Zahnatom]

Challenges & Needs for the Understanding of Combat Aircraft Aerodynamics

here's a paper about the AMK. well, it includes the AMK, it's not necessarily the main topic

Edited January 25, 2023 by Zahnatom

[F-2]

2 hours ago, Zahnatom said:

Challenges & Needs for the Understanding of Combat Aircraft Aerodynamics

here's a paper about the AMK. well, it includes the AMK, it's not necessarily the main topic

 

Thank you for that! 
 

 

Quote

New Tricks

Aerodynamic mods improve Typhoon’s agility

BILL SWEETMANAUGUST 32015

New Tricks

DEFENSE

Aerodynamic mods improve Typhoon’s agility

Bill Sweetman

Washington

Flight tests of a Eurofighter Typhoon with a suite of aerodynamic modifications show they have measurably improved the fighter's subsonic agility, say engineers and pilots involved in the project. The alterations can be easily retrofitted to any Typhoon, it is claimed, and have been demonstrated to pilots from Typhoon partner nations. The Aerodynamic Modification Kit (AMK) is being considered as part of future improvement packages for the aircraft.

The AMK comprises small leading-edge root extensions (Lerx), new delta-shaped fuselage strakes that replace the existing rectangular “step” strakes beneath the canopy sills, and larger flaperons (13% inboard, 8% outboard) that provide more forward sweep to the wings’ trailing edge. The primary function of the Lerxes and reshaped fuselage strakes is to make vortex flows more stable and predictable as the angle of attack (AoA) increases. The larger flaperons provide more roll authority and also counteract the larger nose-up pitching forces introduced by the Lerxes and strakes. “We already have the most unstable production aircraft in the world,” one engineer says. “We don’t need any more pitch-up.”

No new surfaces are added and the existing structure and flaperon actuators can cope with the changes, Eurofighter says, so the main tasks for transition to production would be the design of series-type AMK components and definition of a retrofit process.

The effects of the AMK changes are dramatic, Eurofighter says. Operational AoA limits are increased by 45% and total lift by as much as 25%. The corner speed—defined as the lowest speed at which the aircraft can generate maximum g force, and hence the speed at which the aircraft achieves its highest turn rate and tightest radius—has been “significantly reduced,” increasing maximum turn rate. The usable pitch rate is increased “by far,” according to project test pilot Raffaele Beltrame, and roll rate by up to 100%. The largest improvements are at lower speeds, but performance and handling are also improved in the subsonic regime, and supersonic maneuverability—where the Typhoon is second only to the Lockheed Martin F-22—is unaffected.

Airbus Defense and Space funded the five-year AMK program because the company and its customers believe fighter agility is still crucial. “Beyond-visual-range (BVR) is not the only thing, nor is the helmet-mounted display (HMD). Airframe performance is still decisive and with electronic attack, BVR can easily end up in a close-combat scenario,” says project chief engineer Robert Osterhuber, adding that nose authority—the ability to pitch and yaw the aircraft to put the adversary in the forward hemisphere—is still a key factor in using HMDs and high-off-boresight missiles.

Typhoon’s maneuverability has always been competitive, engineers say, but like all aircraft it has physical limitations. With the fighter’s “carefree handling”—the use of the fly-bywire system to ensure that the pilot cannot cause the aircraft to depart control flight—the stable envelope is protected automatically.

At low speeds, limits on AoA, pitch rate and other parameters are often associated with vortices that form around the forebody and canard at high AoA, and which can cause severe lateral-directional instability if they develop or burst asymmetrically. Very small features toward the front of the aircraft can cause strong vortices.

The step strakes on Typhoon were designed to generate stable vortices, based on computational fluid dynamics (CFD) technology available then. “[Tjoday we have much better tools,” Osterhuber says, and CFD is better integrated with wind tunnel testing. (The AMK configuration underwent extensive testing by the German-Dutch DNW wind tunnel consortium, and in Calspan’s transonic tunnel.) He also notes that, in the past few years, Airbus has improved the sharing of expertise and tools between its commercial and military divisions, including its work with government research institutions.

The result is that with minimal changes, the AMK makes the vortices more stable and predictable, so that they enhance lift and improve pitch response. Less flaperon movement is required for pitch control, so that more authority is available for roll: consequently the increase in roll rate. Beltrame, who has been flying the Typhoon since 2004, calls the improvement “astonishing ... it was a completely different aircraft, and I can say that without implying that the standard aircraft is not good. The potential for nose-pointing and precise tracking is incredible.”

The AMK modifications have not been flight-tested with air-to-ground weapons, but wind tunnel tests of heavy configurations were carried out with positive results, says Beltrame. More control power allows more flexibility in loading and release sequences, and better maneuverability, but he also expects that integration of new weapons and the certification of new combinations will be easier. “Deltas can be very complex in the subsonic regime. With the strakes, it’s more predictable, and easier to create a CFD model.” ©

Galleries See more about aerodynamic modifications for aircraft from the Concorde to F-22: AviationWeek.com/VortexControl

 

 

I saw another article from late 2021 that AMK was still in the cards

 

Quote

FCAS Might Disrupt Multinational Eurofighter Fleet Plans

> ITALY HAS JOINED UK-LED RADAR 2 DEVELOPMENT PROGRAM > FLEET HARMONIZATION FOCUSES ON EUROFIGHTER MISSION-DATA CAPABILITIES

TONY OSBORNEOCTOBER 252021

FCAS Might Disrupt Multinational Eurofighter Fleet Plans

DEFENSE

> ITALY HAS JOINED UK-LED RADAR 2 DEVELOPMENT PROGRAM > FLEET HARMONIZATION FOCUSES ON EUROFIGHTER MISSION-DATA CAPABILITIES

Tony Osborne

London

Eurofighter partner nations are looking to reharmonize their fleets to get ready for the new wave of technology they are preparing for Europe’s nextgeneration combat aircraft.

The four partner nations—Germany, Italy, Spain and the UK—see future development of the Eurofighter as a steppingstone toward the introduction of the Future Combat Air System (FCAS) being developed by Germany and Spain, along with France, and the Tempest FCAS initiative by the UK and Italy. But could such harmonization efforts be in vain? Since all four Eurofighter nations are taking separate paths toward two next-generation fighters, it seems likely that Eurofighter development could again become fragmented, guided by these disparate nextgeneration fighter efforts for the 2030s and beyond.

Airbus has described the Eurofighter as a “natural bridge” to the FCAS, and BAE takes a similar view about the fighter’s links to the Tempest.

Reharmonization is now necessary, industry officials say, particularly with the Eurofighter still chasing major export campaigns such as the one in Finland.

The UK’s Centurion program to equip the Royal Air Force’s Typhoons with capabilities from the now-retired Panavia Tornado gave the UK the most advanced Eurofighters of all four nations but left those of the others far behind.

“Centurion put the UK a long way ahead of the other partner nations,” Andrew Mallery-Blythe, Typhoon Operational Requirements Manager for BAE Systems, told journalists at the Defense Security Equipment International (DSEI) exhibition in London in September.

“It fragmented the program somewhat, and we are not aligned with the other nations,” Mallery-Blythe said, noting that some partner nations have yet to introduce the ramjetpowered MBDA Meteor beyond-visual-range air-to-air missile into service on the aircraft. The weapon has been operational on UK Typhoons since 2018 and will shortly reach frontline units in Germany, but its introduction for Italy and Spain is still some way off.

Mallery-Blythe says the wider program has benefited from lessons learned from that early integration and that these will be “folded into the core program.”

The four nations also have yet to finalize the contents of the Eurofighter’s Long-Term Evolution (LTE) package, seen as a midlife update for the aircraft, although they have recently agreed on a work package—the Consolidation Package Step Two and Three—as part of the fleet harmonization process (AW&ST Aug. 30-Sept. 12, p. 35).

During DSEI, BAE Systems revealed what it sees as the road map for Eurofighter developments that will support new capabilities and help prepare partner nations, particularly those working on the Tempest, to prepare for the introduction of that platform.

These include changes to the power management system and the greater use of mission data and networked communications. As well as the proposed wide-area display cockpit, a development self-funded by BAE Systems, the company is also envisaging what it calls a “common cockpit concept” that could introduce the augmented reality cockpit concepts envisaged for the Tempest. Adopting them on the Eurofighter is a move that could potentially reduce the training burden and enable pilots to fly Eurofighters as well as the future manned combat aircraft that will become the Tempest.

BAE has also been working with the UK Defense Ministry on the potential introduction of its Striker 2 helmet, which would eliminate the need for a cockpit head-up display, smoothing the way for the modernization of the cockpit.

Additional weaponry envisaged for the Eurofighter ineludes the MBDA Spear mini cruise missile and the electronic warfare (EW) derivative Spear EW. The Typhoon would also receive the Future Cruise/Anti-Ship Weapon that will replace the Storm Shadow air-launched cruise missile, as well as the so-called FCAS adjuncts, the uncrewed systems that will work with the manned combat aircraft to perform EW and intelligence, surveillance and reconnaissance as part of a wider strike package.

One of the UK’s Eurofighter aspirations is the dynamic use of mission data such as intelligence on adversary radars. If the fighter’s defensive aids suite senses a new threat, the data collected would be streamed back to mission-data experts using advanced communications systems.

“The intent is to turn that mission data around and in the same mission update your defensive-aids suite,” says Paul Smith, head of business development for Typhoon capability at BAE Systems.

Part of this effort is being supported by Team Novus, a collaboration of BAE Systems, Leonardo, MASS, Meta Mission Data, Sigma and Thales. It was formed in August 2020 to develop means to make better use of mission data.

BAE is also envisaging that partner nations will adopt the Aerodynamic Modification Kit (AMK), first developed by Airbus in Germany in 2015 to provide improved maneuverability and longitudinal stability for the canardequipped aircraft.

According to Mallery-Blythe, introduction of the AMK can make it quicker and easier to integrate new weapons, a costly and time-consuming process on the platform, and could also pave the way for carriage of asymmetric stores.

The UK is set to make investments to ensure the Typhoon meets new international air traffic regulations as well, allowing them to operate in shared airspace as they transit to theater or deploy.

“The aircraft has made astonishing progress in the past few years, and its capability gains have been extremely rapid to make it what is now a very credible swing-role aircraft,” says Mallery-Blythe, a former Royal Air Force Eurofighter pilot himself.

But even with these harmonization efforts, by the middle of the decade there could again be a wide gap between the capabilities of Eurofighters being operated by Germany and Spain on the one hand and by Italy and the UK on the other.

Current UK plans call for the introduction of the Mk. 2 version of the Captor-E active, electronically scanned array radar with its electronic attack capabilities in around 2025. This will be a more powerful radar than the Mk. 1 model envisaged for retrofit on Germany’s Tranche 2 and 3 and the Quadriga buy that will replace Berlin’s Tranche 1 aircraft, giving a “significant [suppression of enemy air defenses] capability,” Mallery-Blythe says.

Italy has subsequently joined the Mk. 2 radar development, with the two countries forming an Industrial Joint Team to develop the sensor. Leonardo says the Mk. 2 radar is not the radar that will feature on Tempest, but much of the technology will feed into the future sensor. Furthermore, BAE Systems is also working on a task-based management system to control the radar and reduce the workload of the pilot.

UK aircraft are due to receive the new Rafael Litening 5 targeting pod, too, likely to enter service before the end of this year.

BAE Systems’ Typhoon to Tempest Road Map

Source: BAE Systems Presentation

 

 

 

Apparently the strakes where tested on the DA5 aircraft years before the AMK kit in 2007

[Zahnatom]

3 hours ago, F-2 said:

Apparently the strakes where tested on the DA5 aircraft years before the AMK kit in 2007

 

that is correct. however, it appears to only have the wing root extensions. the newer AMK(it says kit in the name lol) has different strakes and larger flaperons.

[F-2]

6 hours ago, Zahnatom said:

that is correct. however, it appears to only have the wing root extensions. the newer AMK(it says kit in the name lol) has different strakes and larger flaperons.

Yes your right but the claim was 10% better ITR vs 15% on the AMK, so at least a good chunk of the benefit was possible early on if not the full thing.