In the UK the Hawker Siddeley Aviation company picked up the idea for use with their Harrier V/STOL aircraft. Further development and computer modelling were applied to Taylor’s original ideas by Hawker to produce a full-scale trials programme, conducted at Royal Aircraft Establishment Bedford from 1976-1978[ii]. These proved highly successful and led to the addition of 7⁰ ‘Ski-Jumps’ to HMS Invincible and HMS Illustrious and 12⁰ versions on HMS Hermes and HMS Ark Royal. All of these ships, along with a number of other classes of ‘Harrier Carrier’ operated by several other navies, saw considerable operational success with their ‘Ski-Jumps’, operating several generations of the Harrier until 2010. This is a story of the aircraft carrier ‘Ski-Jump’ that some casual, and most professional, observers will be loosely aware of. A well-known lineage of ramp operations for short and/or vertical take-off and landing aircraft stretching into contemporary naval affairs in the British Queen Elizabeth class, Italy’s Cavour and Trieste and the Spain’s Juan Carlos I.
There is, however, a less well-known story, focusing on the subsequent work
done by several other navies to trial and, in some cases, deploy large
‘conventional’ aircraft from ‘Ski-Jumps’. This piece will focus predominantly
on the American experience of simulating and trialing ramp launch of
conventional carrier and land-based aircraft. This differs significantly from
the experience most V/STOL aircraft operators[iii] have
had of ramp-launching aircraft. While the US studies and test programmes
continued to demonstrate the broad utility and greater relative effectiveness
of the aircraft catapult for launching large, heavy, aircraft under less than
optimal environmental conditions, they also showed that the ramp was no slouch
and proved substantial performance improvements over launch from a flat deck
alone.
Where it gets more interesting, with potential relevance for the configuration of future carriers’ deck layout and equipment, was the demonstration of the novel ‘Carrier Ramp Assisted Take-off’ method: combining a catapult with a ramp of a shallow gradient. A hybrid launch method which has the potential to substantially increase the performance of lower powered aircraft catapults. This technique has the potential for future relevance as a range of aircraft carrier navies begin to examine the operation of lighter, uncrewed, aircraft from their ships’ decks.
The proposal for a hybrid ramp and catapult setup have their origin in the US Navy’s response to the British ‘Ski-Jump’ trials of the late 1970s, which went further than simply replicating the experiment with their own V/STOL aircraft, the AV-8A Harrier.
The US Navy “CTOL” Trials
Following the Harrier ramp trials at RAE Bedford the US Navy initiated its own programme of study to first investigate, and later trial, the concept with their own equipment.
From 1979 analysis and computer modelling of the ‘Ski-Jump’ launch method for Conventional Take-off and Landing[iv] (CTOL) aircraft was conducted at the Naval Air Development Centre, Warminster PA[v]. This led to an initial ‘abbreviated demonstration’ at, ‘Pax River’ Naval Air Station in Maryland from October 1980[vi]. This early demonstration consisted of 15 ramp launches using the T-2C jet trainer as an initial proof of concept.
This concept trial was followed up with what would become the most extensive military testing programme into the launch of CTOL aircraft using a ramp in this period. Run by the US Navy, a total of 231 live test flights took place between 1982 and 1984, over half of which were conducted with modern combat aircraft. Initially the F-14A and later the F/A-18A[viii]. As designed, the test programme was progressive, moving from the initial feasibility flight tests with the T-2C into an extensive 6-month simulation phase in 1981 at the Naval Air Development Centre (NADC) Warminster, PA and the Naval Training Equipment Center (NTEC) in Orlando, FL[ix]. Further NADC simulations were conducted from the second half of 1981 into 1982 for the F-14A. The Navy used the Flight Simulator for Advanced Aircraft at National Aeronautics and Space Administration’s (NASA) Ames Research Centre, CA. The F-14’s manufacturer, the Grumman Aircraft Corporation, also conducted their own simulations for this aircraft through 1982[x]. Live flight testing for the T-2C and F-14A was conducted in the final quarter of 1982[xi].
The live trials utilised fully instrumented test aircraft and a variable geometry ramp 112 or 122ft (depending on the angle) long, able to be configured to an incline of 6⁰ or 9⁰[xii]. These launch angles were significantly shallower than many of those trialled by the British with the Harrier in 1976-8, which ranged from 6⁰ to 20⁰[xiii]. A ‘Holdback/Release Device’[xiv] was also developed “to assist the F-14 and F-18 in maintaining aircraft position at any location on the runway while the engines stabilized at the desired power setting”[xv]. It is noted, in the context of the later F/A-18A trials, that the use of the ‘Holdback Device’ did not cause adverse longitudinal effects on the aircraft such as pitch oscillation or nose-wheel bounce[xvi] on release. From the “CTOL Ski Jump: Analysis, Simulation, and Flight Test” report it does not appear that the T-2C tests used the ‘Holdback Device’, potentially because the lighter and less powerful aircraft did not require it. This device may have made use of these aircrafts’ existing tail hooks, normally used for arrested carrier landings.
The results were significant and promising, with major reductions in required ground roll and minimum required take-off Knot Equivalent Airspeed (KEAS). These are summarised in the tables below.
Tables 4 and 5 show significant reduction in required ground roll for T-2C and F-14A using both the 6⁰ and 9⁰ ramps[xvii].
[F/A-18A data was also included in these tables, but has been removed here to save space, as it is duplicated below in the segment concerning those trials.]
While the reductions in take-off distance for the F-14A were substantial, a 20-25kt reduction in required airspeed for take-off and a 33-36% reduction in the required ground roll distance, the ramp trial did not approach its ~72,900lb[xviii] maximum take-off weight (MTOW), nor did it allow the aircraft to take-off in a distance appropriate for seagoing operations. At 48,000lbs load and using the 9⁰ ramp the F-14A managed a minimum ground roll of 1250ft[xix] whereas the Navy’s newest class of aircraft carrier: the first three nuclear-powered Nimitz class CVNs, only had a deck just over 1000ft long[xx]. A takeoff at these reduced weights from a runway the length of a US Carrier deck may, however, have been possible with substantial ship and weather generated wind over the deck but this was not trialled. A total of only 28[xxi] test launches were conducted with the F-14A, significantly fewer than for the T-2C and F/A-18A. It is notable that the F-14A was not pushed to the limits of its capabilities using the ramp, in part due to a minimum take-off speed limit of 100kts, driven by safety factors should the aircraft have suffered a single engine failure during take-off[xxii]. This was not a constraint placed on the T-2C or F/A-18A; both of which conducted ramp launches at air speeds below this 100kt threshold[xxiii]. However, removing this constraint is unlikely to have made sufficient difference to allow an F-14A, even in these lightly loaded configurations, to take-off safely in under 1000ft.
The later set of trials with the F/A-18A were extensive, beginning with 12 months simulations from 1982-1983, conducted by NADC and making use of McDonnell Douglas’ Manned Aircraft Combat Simulator in St. Louis, MO[xxiv]. These led to a total of 91 live launches in a range of configurations and profiles conducted from 1983 to 1984[xxv]. These were conducted using two weight profiles for the aircraft: 32,800lbs and 37,000lbs, varied using the fuel load. All trials were conducted with the same dummy armament: two inert Sparrow and two inert wingtip Sidewinder missiles[xxvi]. The maximum trialled weight profile was significantly below the take-off weight required for ground attack, around 49,000lbs[xxvii]. Although it’s notable that these trials never progressed to the stage where launching with these greater payloads was tested, standing instead more as an initial investigation of performance gains and structural loads[xxviii] rather than full development of an operational capability.
It is also notable that the F/A-18A used in this trial was itself a very new aircraft, barely out of the 1979-1982 pre-production testing phase, at the time these trials were conducted. One which had still yet to remedy several of its own issues with weight, drag, cruise performance and safety[xxx]. Despite this, the results of the trial were highly positive: significant reductions of up to 66% in the ground roll distance to take-off using the 9⁰ ramp, down to 575ft in the heavier configuration and using afterburner during take-off.
This trial also highlighted the potential further performance gains possible with a ramp launch by deviating from the Navy’s ‘stick free’ approach to flying the aircraft during launch to a novel ‘pitch attitude capture’ method. The pilot would allow the aircraft to pitch upwards to 18 degrees after leaving the ramp, before checking the flight control system’s return to the aircraft’s set trim at 15 degrees, better exploiting the advantage provided by the ramp over the ‘stick free’ method; which only resulted in 12 degrees of upwards pitch[xxxii]. Safe launch, abort and ejection parameters in the event of single engine failure were also established.
These trials proved that reduced take-off runs, using a ‘Ski-Jump’, were possible with a range of CTOL aircraft. They demonstrated that launching a moderately loaded aircraft, using only the ramp and a short ‘ground roll’ was possible in the distances available aboard an aircraft carrier at-sea, without the need for a catapult. Early experimentation also began to establish some of the ways that operating aircraft in this manner might begin to diverge from the procedures used by the US Navy to launch its aircraft from a ‘conventional’ aircraft carrier. Further recommendations included the desirability of a Head-Up Display, nosewheel steering, stability augmentation in all axes, and an accurate and repeatable flight control trim system[xxxiii].
Follow-on at-sea trials with CTOL aircraft were not conducted, although a parallel programme of testing using the V/STOL AV-8B Harrier did see sea trials aboard the Spanish light aircraft carrier Principe de Asturias, in December 1988[xxxv]. These were highly successful and drew significant praise in the 1989 report: “United States Navy ski jump experience and future applications”, for the substantial improvements in payload (in the region of a 53% increase), safety and improved interoperability with helicopters, due to the shorter deck-run allowing space for concurrent helicopter operations aft[xxxvi].
The US Air Force Study
Building upon the US Navy’s work in the first half of the 1980s the US Air Force conducted its own study into the use of ramps with conventional aircraft entitled ‘Aircraft Operations From Runways With Inclined Ramps (Ski-Jump)’ which ran from 1982 until its publication in 1991[xxxvii]. The focus was, unlike the US Navy’s, on reducing take-off distances for non-carrier capable aircraft; as a possible solution to the problem of European runway denial in the context of the Cold War[xxxviii]. The role of the Structures Division, who authored the Study, was to:
In the course of this task they analysed ramp launches of five different aircraft: the A-7D, EWAA-10, F-4E, F-15 and F-16. The Air Force study used the Navy’s 9⁰ ramp as a baseline, for which they subsequently specified modifications (although the final launch angle remained the same throughout)[xl]. These modifications principally focussed on reducing the excessive loads on the aircraft’s landing gear that would occur during ramp-assisted take-off. This had not been a significant issue during the Navy trials, due to the more robust undercarriage of aircraft designed for catapult launch and arrested recovery[xli].
Interestingly, despite being originally designed for launch and recovery from aircraft carriers, the F-4E was assessed as being wholly unsuitable for launch using a ramp. This was due to the rather unfortunate risk that “the aircraft would continue to pitch nose-up past the maximum allowable angle of attack.”[xliii]. Essentially the report concluded that, without the pilot pulling off a precise manoeuvre immediately upon leaving the ramp, the aircraft would almost certainly pitch nose up beyond its critical angle of attack[xliv], stall and (inferring what comes next) crash.
Thankfully, none of the other aircraft in the study suffered from this issue. Indeed, like the Navy’s earlier findings, the Air Force Study pointed towards significant reductions in the take-off roll required by all the remaining aircraft. F-15 and F-16 saw the most relative benefit from the ramp. With a 65-70% reduction in take-off roll for the F-16 and a 55-60% reduction for F-15.
Unsurprisingly the aircraft with the greater thrust to weight ratio, F-15 and F-16, saw greater benefit from the ramp than the slower A-7D and A-10. However, all saw in excess of 40% reduction in required ground roll distance to take-off.[xlv] Unfortunately for the Air Force the attractive headline hides the fact that, even with the modified Navy ramp[xlvi], they were still unable to launch most of the aircraft included in the study at ‘combat weights’ due to the excessive stress this would have on the aircraft’s landing gear by the use of the ramp, above a certain threshold, expressed in Figure 4 below[xlvii].
Overall, the Air Force Study did not lead to live trials as the Navy’s had. Likely in part due to the end of the Cold War in 1990-91, when the Study’s findings were released, and the associated end to the requirement that had driven the Air Force to consider ramp-launching aircraft in the first place: potential runway denial in the European Theatre of Operations.
Interestingly, the study did not write-off the potential for ramp-launch of conventional land-based aircraft as impractical (except for in the case of the F-4E). Instead concluding that a longer (180ft) ramp, able to impart the desired part-ballistic effect as the aircraft departs the ramp, without placing excessive stresses on the aircraft’s landing gear was a viable option for the launch of A-7D, F-15 and F-16. The latter two would benefit the most, with an expected reduction in ground roll of over 50%[xlviii].
The ‘CRAT’
Proposal and Foch
One of the more strident arguments, that came from the US Navy’s 1980s investigation of the use of ramps to assist in the launch of aircraft from ships at sea, is the potential benefits of ‘CRAT’ - Carrier Ramp Assisted Take-off[l].
Even before the British trials in the 1970s, the idea of using an inclined ramp to assist with launching aircraft from a carrier was not entirely alien to the Americans. A 1952 study by the National Advisory Committee for Aeronautics (NACA) had investigated the possibility of using a shallow 50-foot ramp (inclined at approximately 2⁰), positioned forward of a carrier’s catapults, to limit loss of altitude at low speeds immediately after launch[li].
This approach was further analysed following the US Navy’s 1980s ramp trials, although no practical testing was ultimately conducted (likely due to the need to convert a seagoing catapult-equipped ship to conduct the trials). Lea, Senn and Clark’s proposal, contained in ADA 244869: United States Navy Ski-Jump Experience and Future Applications, was for a 42½ft ‘mini-ramp’ with a 2.1⁰ elevation, placed ahead of the catapults[lii]. This had the distinct advantage of avoiding the risks and limitations imposed by excessive landing gear stress noted in the previous studies.
Their model calculated the minimum catapult end speed required to generate a set maximum altitude loss (a range of values between 10 and 20ft) or Zero Minimum Rate of Climb (the point at which the aircraft achieves a positive rate of climb) and then compared these with the catapult end speeds required to generate the same outcomes with the inclusion of the ‘mini-ramp’.[liv]
Unfortunately I have yet to find evidence that the practical trials, mentioned in Senn et. al.’s report[lix], actually took place. It is possible that the documentation covering this is not easily available in the public domain. Alternatively, like the fate of the USAF Study, practical trials of the concept may have been scuppered by the end of the Cold War and the perceived reduced need to invest in heavy carrier-borne strike aircraft that steadily came to the fore in the US Navy after 1991[lx]. It may not have helped, certainly in the long-term, that the CRAT concept mainly benefitted the heavier types. That said, the US Navy continued to operate upgraded variants of the F-14 for over a decade after 1991. As the report’s authors note, however, the CRAT concept wasn’t without its own issues which, may also have militated against further trials and the concept’s operational implementation. Notably the problem of retrofitting the proposed ramps forward of the catapults on existing carriers[lxi]. Questions were also raised about whether a carrier’s waist catapults could safely feature such ramps (due to possible risks for ‘bolters’[lxii])[lxiii].
Interestingly, while there is scant evidence in the English-language public domain about the origins and effectiveness of it, this concept has been employed in practice on an operational carrier. The French carrier Foch was retrofitted with a 30ft long ramp inclined at 1⁰, which operated in tandem with her catapults, during her 1992-3 refit,[lxiv]. This was in order to allow her to operate the new Rafale M, the loaded mass of which was close to the limits of the ship’s elderly BS-5[lxv] catapults, rated for 50,000lbs and a launch speed of 91kts[lxvi]. The setup operated in a manner almost identical to that envisaged by the US CRAT concept, with the ‘mini-ramp’ fitted atop the decommissioned bridle catcher and forward of the catapult[lxvii]. It is claimed that the 30ft 1⁰ ramp may have improved the aircraft’s take-off performance by the equivalent of 20kts of wind over the deck (WOD), or 2000lbs of additional aircraft payload that could be launched for any given windspeed[lxviii]. This compared favourably with the Rafale’s ‘jump strut’ (effectively a shock-absorber that releases its energy at the end of the catapult stroke, to assist in ‘bouncing’ the aircraft off the deck[lxix]) which only gave an advantage equivalent to around 9kts of WOD or 900lbs of payload[lxx]. It certainly ties closely to the US analysts’ prediction that CRAT (using a slightly longer and more steeply inclined ramp) could:
The more powerful 60,000+lb class C-13-3 catapults fitted to the new French carrier Charles de Gaulle, likely removed the perceived need for the ramp; which was not included on the new ship. With the new ship, the Rafale M would also make operational use of its nose-wheel ‘jump strut’ (which was intentionally not used alongside the Foch’s ‘mini-ramp’[lxxii]).
Super Hornet, Rafale, Gripen and STOBAR for India
Finally, we come to something significantly more recent and therefore, unfortunately, carrying a lot less information available in the public domain. Much of what we do know is limited to recent press releases and is broadly summarised here.
In early 2017 India submitted a request for information to a number of Western aircraft manufacturers investigating the options available for the possible procurement of 57 ‘multirole carrier-borne fighters’ (MRCBF), capable of undertaking a wide range of missions[lxxiv]. The major prospective competitors were Boeing, Dassault and SAAB with the Super Hornet, Rafale and Gripen as the potential competitors[lxxv]. All have since claimed that their aircraft can operate from both catapults and from the ramps[lxxvi] currently in use by the Indian navy’s present generation of aircraft carriers[lxxvii]. The ability to operate a single fleet of aircraft using these two different launch and recovery methods may be particularly important for India as its next generation aircraft carrier, IAC-2[lxxviii], may feature catapults and arrestor wires[lxxix]. There is certainly awareness of the limitations of the Short Take-Off But Arrested Recovery (STOBAR) method within Indian defence[lxxx].
Chasing a potential sale of Block III F/A-18E/F for MRCBF, Boeing and the US Navy have moved forward with a programme of simulation and live testing[lxxxi]. This is reportedly building upon earlier simulation work for STOBAR operation of the Super Hornet conducted in the late 2000s[lxxxii]. Live testing of the Super Hornet, once again using a ramp at Pax River NAS, went ahead in December of 2020[lxxxiii]. Judging by the available imagery of these tests and the geometry of the ramps used on India’s carriers (which Boeing was very likely trying to prove that they could operate their aircraft from) I believe that the ramp used was the same 12⁰ structure used to trial the STOVL F-35B[lxxxiv].
Dassault are due to commence their own ramp trials with the Rafale M at INS Hansa, India’s naval air station in Goa, beginning in early 2022[lxxxviii]. While the SAAB Sea Gripen is also believed to be competing[lxxxix] the aircraft has only been stated to be suitable for Short-Take-off and Landing in the context of the Swedish Air Force’s requirement to operate from improvised runways[xc] at present. I am not aware of a programme of systematic, or even simple proof of concept, live testing conducted with any variant of the Gripen from a Ski-Jump to-date. Certification of the ‘navalised’ variant of the aircraft appears to have been conducted via “model-based systems engineering practices perfected by SAAB”[xci] rather than live tests.
Concluding Remarks
While the experiences of the various navies discussed here warrants interest in its own right, as a testament to years of work and study by a great many people, these studies demonstrate enduring relevance in a world where three of the more recent additions to the fleet carrier ‘club’: Russia, India and China, operate STOBAR type ships and its most recent return member, the United Kingdom, now also operates large ramp-equipped carriers (albeit using the STOVL F-35B, rather than a STOBAR aircraft). Furthermore, many of the operators of smaller carriers have also chosen designs with in-built ramps to assist with launching their aircraft. From the Italian Light carriers Cavour and Trieste to the Turkish Anadolu and Spain’s Juan Carlos I ramps remain as popular and relevant for aircraft operations now as they did in the 1980s; and for largely the same reasons. They are simple, cheap, non-mechanical structures that impart substantial launch-performance benefits over a simple flush deck. Able to reduce required take-off roll distances significantly for all classes and weights of aircraft, if not allow for the safe operation of the heaviest types of aircraft without adding-in favourable external factors (additional WOD generated by weather and the ship steaming into wind, for example). The main constraining material factor has usually, as the USAF Study found, been the ability of the aircraft’s undercarriage to withstand the significant forces involved in a ramp-launch, all else is a matter of having a sufficient ratio of thrust to weight to take-off in the available distance.
There is also a final enduring point that, since the Second World War, the carrier navies of the world have looked at a wide range of novel launch and recovery methods. Some innovations, like the slightly comedic, to modern eyes, ‘flex deck’[xcv] (a rubberised flexible sheet on the carrier’s deck, which allowed early jet aircraft to belly-land without the need for an undercarriage) understandably did not make it much past the testing phase. The ‘Ski-Jump’ sits alongside the steam (and now electromagnetic) catapult, wire arrestor system and angled deck as one of the most prolific and successful innovations in its field. It does this for a range of reasons which are as straightforward as the device itself. Foremost amongst them is that it is simple, robust, and demonstrably very effective.
Comment:
As many of you may be able to see, this piece has been significantly longer in form than some of my usual content. Considerable time went into researching and writing it, but without the handful of people kind enough to support me with the inciting idea, direction, proof-reading and final edits this would not be the piece you've read today. To all you awesome people, you know who you are, I extend my warmest thanks and wish you all a Merry Christmas.
-ES
[i] Although there is evidence that HMS Furious (47) launched heavily laden Fairey Barracuda attack aircraft using a makeshift ramp in the strike on the battleship Tirpitz, Operation Mascot (July 1944), the structure was later removed and the idea was not systematically pursued.
[ii] Hobbs, D. “British Aircraft Carrier Design that Led the World”, Pen & Sword Blog, https://www.pen-and-sword.co.uk/blog/david-hobbs-british-aircraft-carrier-design-that-led-the-world-part-2/ (20 June 2020) ,
[iii] While the US Marine Corps have invested in, and operated, several V/STOL aircraft types in the form of the AV-8A and AV-8B Harriers and more recently the F-35B, the US Navy have never operationally employed those aircraft from their own ships fitted with ‘Ski-Jumps’.
[iv] These aircraft were actually those designed for catapult launch and arrestor wire recovery, described by the US Navy at that time as a “Conventional” take-off and landing. More recently alternative terminology such as CATOBAR (Catapult Assisted Takeoff But Arrested Recovery) has entered use to describe this mode of aircraft launch and recovery. While CTOL has, in modern parlance, often been used to describe aircraft designed to take-off and land using runways ashore. This piece will reference period-appropriate terminology and seek to clarify where appropriate for a modern audience.
[v] Clark, J. and Walters, M. “CTOL Ski-Jump: Analysis, Simulation and Flight Test”, Journal of Aircraft, Vol.23, No.5, (May 1986), p.382
[vi] Ibid.
[vii] Russel, D. “US Navy 040303-N-6842R-025: Lt. Allen Karlson, a student pilot assigned to the "Tigers" of Training Squadron Nine (VT-9), with instructor Cdr. Joe Kerstiens (USNR) sits "shotgun"(rear seat) evaluating.”, US Navy Training Squadron 9, (14 September 1991).
[viii] Clark, J. and Walters, M. “CTOL Ski-Jump: Analysis, Simulation and Flight Test”, Journal of Aircraft, Vol.23, No.5, (May 1986), p.383
[ix] Ibid.
[x]Ibid.
[xi] Ibid.
[xii] Ibid, p.385
[xiii] Darling, K. “BAe Sea Harrier”, Warpaint No.75, Warpaint Books Ltd, (2010), p.1-8
[xiv] Clark, J. and Walters, M. “CTOL Ski-Jump: Analysis, Simulation and Flight Test”, Journal of Aircraft, Vol.23, No.5, (May 1986), p.385
[xv] Ibid.
[xvi] Senn, C., Clark, J and Lea, T. “ADA 244869: United States Navy Ski-Jump Experience and Future Applications”, Aero Analysis Division, Naval Air Development Centre, Warminster PA and Strike Aircraft Test Directorate, Naval Air Test Centre, Patuxent River MA (1989), p.9
[xvii] Clark, J. and Walters, M. “CTOL Ski-Jump: Analysis, Simulation and Flight Test”, Journal of Aircraft, Vol.23, No.5, (May 1986), p. 388
[xviii] Pike, J. “F-14 Tomcat”, Federation of American Scientists Military Analysis Network, https://man.fas.org/dod-101/sys/ac/f-14.htm, (2 November 2016)
[xix] Clark, J. and Walters, M. “CTOL Ski-Jump: Analysis, Simulation and Flight Test”, Journal of Aircraft, Vol.23, No.5, (May 1986), p.388
[xx] Pike, J. “CVN-68 Nimitz Class”, Federation of American Scientists Military Analysis Network, https://man.fas.org/dod-101/sys/ship/cvn-68.htm, (8 January 2000)
[xxi] Clark, J. and Walters, M. “CTOL Ski-Jump: Analysis, Simulation and Flight Test”, Journal of Aircraft, Vol.23, No.5, (May 1986), P.383
[xxii] Leone, D. “Rare Photo Shows An F-14A Tomcat Taking Off from A Ski-Jump”, The Aviation Geek Club, https://theaviationgeekclub.com/rf-14a-tomcat-taking-off-ski-jump/, (17 February 2017)
[xxiii] Clark, J. and Walters, M. “CTOL Ski-Jump: Analysis, Simulation and Flight Test”, Journal of Aircraft, Vol.23, No.5, (May 1986), p. 388
[xxiv] Ibid, p.385
[xxv] Ibid, p.383
[xxvi] Senn, C., Clark, J and Lea, T. “ADA 244869: United States Navy Ski-Jump Experience and Future Applications”, p.6
[xxvii] Boeing, “F/A-18 Hornet Fighter: Historical Snapshot”, Boeing, https://www.boeing.com/history/products/fa-18-hornet.page , (2016)
[xxviii] Senn, C., Clark, J and Lea, T. “ADA 244869: United States Navy Ski-Jump Experience and Future Applications”, p.6
[xxix] Ibid.
[xxx] Chambers, J. “Partners in Freedom: Contributions of the Langley Research Center to U.S. Military Aircraft of the 1990's”, CreateSpace Independent Publishing, (2013), p. 35-42
[xxxi] Senn, C., Clark, J and Lea, T. “ADA 244869: United States Navy Ski-Jump Experience and Future Applications”, p.8
[xxxii] Ibid, p.7
[xxxiii] NASA Scientific and Technical Information Facility, “Aeronautical Engineering a Continuing Bibliography with Indexes (Supplement 200)”, NASA Scientific and Technical Information Branch, Washington DC, (1986), p.222
[xxxiv] Newdick, T. “Watch a Super Hornet launch off a ‘Ski-Jump’ During Testing Aimed at the Indian Navy”, The Drive.com, https://www.thedrive.com/the-war-zone/38324/watch-a-super-hornet-launch-off-of-a-ski-jump-during-testing-aimed-at-the-indian-navy, (21 December 2020).
[xxxv] Nalls, A. “Harrier Operations on a Ski-Jump”, Naval Aviation News, Naval Historical Centre, Washington DC, Vol. 72, No.4, (May-June 1990), p. 12-13
[xxxvi] Senn, C., Clark, J and Lea, T. “ADA 244869: United States Navy Ski-Jump Experience and Future Applications”, p.5
[xxxvii] Turner, E. “ADA-237 265: Aircraft Operations from Runways with Inclined Ramps (Ski-Jump)”, Flight Dynamics Directorate, Loads and Criteria Group, Structures Division, Wright Patterson AFB, Ohio, (May 1991), p.ii
[xxxviii] Ibid, p.iii
[xxxix] Ibid, p.2
[xl] Ibid, p.7
[xli] Ibid, p.8
[xlii] Scharringa, G. "History and Units of the United States Air Forces In Europe", European Aviation Historical Society, (2004).
[xliii] Ibid, p.6
[xliv] Ibid.
[xlv] Ibid, p.7
[xlvi] This ingenious concept essentially ‘smoothed out’ the load on the aircraft’s landing gear by including a steeper “Wedge” in front of the 9⁰ Navy ramp. This rapidly increased the load on the aircraft’s landing gear to around 90% of its maximum, before allowing it to reduce as the ramp’s incline reduced. The final portion of the ramp would then induce a greater gear load, but still below the 90% maximum threshold, as the aircraft completed the final component of the ramp with a greater incline.
[xlvii] Turner, E. “ADA-237 265: Aircraft Operations from Runways with Inclined Ramps (Ski-Jump)”, Flight Dynamics Directorate, Loads and Criteria Group, Structures Division, Wright Patterson AFB, Ohio, (May 1991), p.8
[xlviii] Ibid, p.13
[xlix] Yangang, Wang & Weijun, Wang & Xiangju, Qu. (2013). “Multi-body dynamic system simulation of carrier-based aircraft ski-jump takeoff.”, Chinese Journal of Aeronautics, No.26. (Dec 2012), p.104–111.
[l] Senn, C., Clark, J and Lea, T. “ADA 244869: United States Navy Ski-Jump Experience and Future Applications”, p.10
[li] Reed, W. “RM L52105: An Analysis of the Effect of a Curved Ramp on the Take Off Performance of Catapult Launched Airplanes”, National Advisory Committee for Aeronautics, (5 November 1952), p.5
[lii] Senn, C., Clark, J and Lea, T. “ADA 244869: United States Navy Ski-Jump Experience and Future Applications”, p.10
[liii] Ibid, p.14
[liv] Ibid, p.12
[lv] Ibid, p.11
[lvi] Ibid.
[lvii] Ibid, p.13
[lviii] Ibid.
[lix] Ibid, p.14
[lx] Hendrix, J. “Retreat From Range: The Rise and Fall of Carrier Aviation”, Center For a New American Security, Washington DC, (2015), p.45-47
[lxi] Senn, C., Clark, J and Lea, T. “ADA 244869: United States Navy Ski-Jump Experience and Future Applications”, p.14
[lxii] A ‘Bolter’ is an aircraft that fails to catch an arrestor wire whilst attempting to land on a carrier and therefore has to fly the deck and attempt another landing.
[lxiii] Senn, C., Clark, J and Lea, T. “ADA 244869: United States Navy Ski-Jump Experience and Future Applications”, p.14
[lxiv] Janes “Dassault Rafale”, Janes: All the World’s Aircraft Online, https://janes.migavia.com/fra/dassault/rafale.html (2021)
[lxv]Navypedia, “Clemenceau Aircraft Carriers: 1961-1963”, Navypedia, https://www.navypedia.org/ships/france/fr_cv_clemenceau.htm (2021)
[lxvi] Hobbs, D. “British Aircraft Carriers: Design, Development and Service Histories”, Seaforth Publishing, Barnsley, (2013), p. 296
[lxvii] Robineau, F. “Rafale Marine Version Landing and Taking Off From the Aircraft Carrier Foch”, La Jaune et La Rouge, No.486, (June 1993), Cover Image.
[lxviii] Janes “Dassault Rafale”, Janes: All the World’s Aircraft Online, https://janes.migavia.com/fra/dassault/rafale.html (2021)
[lxix] Ibid.
[lxx] Ibid.
[lxxi] Clark, J. and Walters, M. “CTOL Ski-Jump: Analysis, Simulation and Flight Test”, Journal of Aircraft, Vol.23, No.5, (May 1986), p. 389
[lxxii] Presumably for safety reasons.
[lxxiii] Robineau, F. “Rafale Marine Version Landing and Taking Off From the Aircraft Carrier Foch”
[lxxiv] Waldron, G. “Analysis: Asia’s Aircraft Carrier Renaissance”, Flight Global, https://www.flightglobal.com/analysis/analysis-asias-aircraft-carrier-renaissance/127495.article, (3 May 2018)
[lxxv] Ibid.
[lxxvi] Ibid.
[lxxvii] The modified ex-Soviet Kiev class carrier INS Vikramaditya and India’s first native built carrier INS Vikrant, both of which are fitted with a ski jump and arrestor wires.
[lxxviii] Prospectively named INS Vishal.
[lxxix] TNN, “US Defence Secretary to Visit India in May to Push Aircraft Carrier Technologies”, Times of India Online, https://timesofindia.indiatimes.com/india/us-defence-secretary-to-visit-india-in-may-to-push-aircraft-carrier-technologies/articleshow/46818785.cms, (6 April 2016)
[lxxx] Kahlon et. al. “A Brief Review on Electromagnetic Aircraft Launch System” , International Journal of Mechanical and Production Engineering, Bhubaneswar, Odisha, India, Vol. 5, Issue 6, (June 2017), p. 59-60
[lxxxi] The Week, “Boeing Testing Super Hornet Fighter From ‘Ski-Jump’ for Indian Navy Deal”, The Week Online, https://www.theweek.in/news/india/2020/08/20/boeing-testing-super-hornet-fighter-from-ski-jump-for-indian-navy-deal.html, (20 August 2020)
[lxxxii] Ibid.
[lxxxiii] Charpentreau, C. “Boeing F-18 Super Hornet shows ability to ski-jump off India's carrier ramp”, Aerotime, https://www.aerotime.aero/26767-super-hornet-shows-ski-jump-off-carrier-ramp-india, (22 December 2020)
[lxxxiii] Joe, J. “Pax Hosts New Round of F-35 Ski-Ramp Tests”, The Lexington Park Leader Online, https://lexleader.net/pax-hosts-new-round-of-f-35-ski-ramp-tests/, (25 July 2017)
[lxxxv] Charpentreau, C. “Boeing F-18 Super Hornet shows ability to ski-jump off India's carrier ramp”,
[lxxxvi] Mathews, N. “Aero India 2021: Naval Fighters Prove Their Mettle”, Shephard Media Online, https://www.shephardmedia.com/news/air-warfare/aero-india-2021-naval-fighters-prove-their-mettle/, (4 February 2021)
[lxxxvii] Leone, D. “Boeing Says India Can Launch the Super Hornet from INS Vikrant’s Ski-Jump with Significant Payload”, Aviation Geek, https://theaviationgeekclub.com/boeing-says-india-can-launch-the-super-hornet-from-ins-vikrants-ski-jump-with-significant-payload/, (27 July 2018)
[lxxxviii] Charpentreau, C. “Rafale M Fighter Jet to Attempt Ski-Jump Takeoff from India's Carrier Ramp”, Aerotime, https://www.aerotime.aero/29240-rafale-to-attempt-ski-jump-takeoff-in-india, (20 October 2021)
[lxxxix] Mathews, N. “Aero India 2021: Naval Fighters Prove Their Mettle”,
[xc] Frahan, A. “SAAB Promotes its "Sea Gripen", a Possible Naval Variant of the Gripen NG Fighter Jet”, Navy Recognition Online, https://www.navyrecognition.com/index.php/homeb/about-us.html, (2013)
[xci] SAAB Gripen Blog, “Gripen Maritime for India”, SAAB, https://www.saab.com/markets/india/stories/2020/gripen-maritime-for-india, (8 April 2020)
[xcii] The US Navy’s Electromagnetic Aircraft Launch System whose 300ft stroke can launch a 100,000lb class aircraft up to 130kts.
[xciii] Bal, A. “Turkey’s TCG Anadolu to Allow Drones to Land, Takeoff in Global 1st”, Daily Sabah Online, https://www.dailysabah.com/business/defense/turkeys-tcg-anadolu-to-allow-drones-to-land-takeoff-in-global-1st, (25 March 2021)
[xciv] Hansard, SC Oral Evidence, HC168, “The Navy: purpose and procurement”, Q317 (2 November 2021)
[xcv] Davenport, A. “Improvements in or Relating to Apparatus for Facilitating Landing of Aircraft”, UK Patent No. GB742240A, UK Intellectual Property Office, (21 December 1955)
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