Upgraded Merlin HC Mk3 Conversion sets

[davepb]

Hi, is anyone planning to issue a folding tail conversion and upgrade for the Airfix HC.3 to make the Royal Navy HC.4?

[exdraken]

And other conversions for international 101s!!

[Edge]

I'd be interested in an HC.4 conversion. Seem to recall Fred, otherwise known as Gengriz, scratched a conversion quite recently, but possibly a bit too much for my limited skills.

 

Edge

 

[Avro730]

As some years have now passed, perhaps there is a conversion set available? or failing that anyone done a scratch conversion or a list of the differences? 

[detail is everything]

Please also see  

 

There were significant differences between the HC3 and HC3A.  Many of those disappeared when the HC3As were upgraded to HC4As, but there are still some subtle differences. and the above topic looks at those.

 

See the 2018 https://www.key.aero/article/commando-merlin article from which I repeat much of here

 

Merlin life sustainment programme (MLSP)

 

 Old variants of the 101/Merlin had a teetering tail rotor (TTR). In about 2007/8 the Merlin fleet was switched to a fully articulated tail rotor (ATR). To the best of my knowledge, all existing model kits 72 and 48, include the earlier teetering tail rotor only. The tail rotor blades are different, at the blade root, on the articulated tail rotor.

 

As the Westland Sea King HC4 Out of Service Date (OSD) approached in March 2016, the UK MoD announced during January 2014 that Augusta Westland (AW) now Leonardo Helicopters (LH) had been awarded the contract to convert 25 former RAF Merlin HC3/ HC3A helicopters for maritime operations.

 

Valued at approximately £455 million, the Merlin Life Sustainment Programme or MLSP had two primary elements: first, a life sustainment package to resolve legacy obsolescence out to the types planned 2030 OSD, similar to the major upgrade of 30 Merlin HM1 to HM2 standard completed by the company in July 2016; second, a ship optimisation package to enable the aircraft to operate more effectively from ships in the maritime environment.

 

The MLSP involved the upgrade of two variants, namely, 19 HC3 to HC4 standard and six HC3A to HC4A standard. The six HC3A aircraft were acquired by the MoD from Denmark in 2007. Having been purchased from AW approximately ten years after the UK received its Merlin HC3s, the six former Danish HC3As naturally incorporated a number of enhanced technical features over their UK counterparts, owing to their role as a specialist SAR platform. Whilst the two variants were both powered by Rolls-Royce Turbomeca RTM322 engines, they had different power rating structures, for example. The UK HC3 also had a four-tank fuel system compared to five for the former Danish HC3A, and the respective cockpit and window layouts were significantly different. Externally, the HC3A could be easily distinguished from the HC3 by its distinctive nose cone, which was designed to enable a laser obstacle avoidance system to be fitted in addition to a weather radar and electro-optical device.

 

As I said at the top of this post, the MLSP addressed most of the variant differences that existed, but not all of them.

 

The MLSP contained two distinct conversion phases.

 

Phase 1

This phase saw seven aircraft converted to interim HC3 (also referred to as iMk3) standard to enable the CHF to maintain embarked operations and to bridge the capability gap between the Sea King OSD set for March 2016 and the service introduction of the Merlin HC4/HC4A in early 2018. The critical design review (CDR) for this upgrade was concluded by June 30, 2014, with the first aircraft ZJ122/F (c/n T1) arriving at LH facility in Yeovil for upgrade on October 23, 2014. Key features of this upgrade were:

• Ground crew controlled folding main rotor head (non-folding tail)
• New fast roping and abseiling point
• Modified undercarriage for deck operations
• New aircraft lashing points for deck security
• Additional radio

The iHC3 first flight took place on March 24, 2015, six months before the aircraft’s initial release to service on September 30, 2015. Initial operating clearance was exactly one year after the aircraft’s first flight on March 24, 2016. All seven aircraft were delivered to the MoD and Royal Navy (845 and 846 NAS) ahead of a schedule that the MoD itself considered ‘demanding’. The last flight of an iMk3 prior to conversion to HC4 was 27 July 2021

 

Phase 2

This involved the conversion of 25 aircraft to full HC4/HC4A standard. The CDR for this phase was March 31, 2015, with the first aircraft (TI#1) arriving at Yeovil approximately four months later on August 5, 2015. Additional modifications made to the iHC3 focus primarily on the upgrade of the cockpit and ship optimisation. The modifications are as follows:

• Key features of avionics design include
  • upgraded aircraft management and mission computers,
  • General Dynamics tactical processor (derived from the Wildcat),
  • five 10 x 8inch (254 x 200mm) General Electric integrated display units,
  • three BARCO touchscreen units for controlling the aircraft’s systems and mission equipment,
  • two devices for cursor control of the tactical displays,
  • a communication suite (derived from Merlin HM2 communication control and intercom system) with a specific radio fit for the HC4/HC4A requirement, and
  • an I-band transponder system navigational equipment (again, similar to the HM2, but integrated into the aircraft avionics)
• Integrated defensive aids suite with additional chaff dispensers mounted in the roof of the aircraft.
• Additional systems for civil airspace operational requirements include a civil twin global positioning system, dual VHF omnidirectional range/instrument landing system
• Folding main rotor head and tail pylon, cockpit controlled as per HM2
• Fast roping and abseiling beam
• Modified undercarriage (uprated from that done under phase 1) and new aircraft lashing points for deck operations (if not already added in phase 1)

 

The first HC4 made its initial flight on October 24, 2016. The first HC4A was expected to fly in early 2019 (I don't know the actual date). All 25 helicopters were scheduled to be delivered by December 2020, with full operational capability also set for the end of 2020. 

 

As operational frontline aircraft, LH confirmed they were not be deemed as out of service when they arrived at their Yeovil facility for upgrade; the airframe and HC3/3A legacy equipment were still classed as being in service and they were therefore maintained in accordance with each aircraft’s specific maintenance schedule. In theory, some aircraft went to Yeovil to receive depth maintenance before entering the HC4/HC4A upgrade programme.

 

Upgrade of the cockpit

 

The early Merlins (HC3 and HM1) had a different cockpit display, consisting of 6 display screens, compared to the later variants HM2 and HC4, they now have 5 display screens and two touch screens, 

 

See http://www.seaforces.org/marint/Royal-Navy/AIRCRAFT/Merlin-HC3-RN.htm and http://www.seaforces.org/marint/Royal-Navy/AIRCRAFT/Merlin-HC4-RN.htm for lots of high quality photos including cockpit shots.  There are plenty of other photographs on the internet. 

 

 

 

 

Edited March 10, 2023 by detail is everything

[Navy Elephant]

As of today 20th Jan 2024 [email protected] would be willing to do this if there was a sufficient set of CAD drawings suitable for a 3D printer set up.