February 2025 Part 1

Hawker Siddeley Kestrel FGA.1

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Hawker Siddeley Kestrel FGA.1

Tripartite Evaluation Squadron (TES)

RAF West Raynham, 1965

Fujimi AV-8A with scratch conversion & inkjet decals1/72

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Text & Images  © www.gengriz.co.uk (unless otherwise indicated)


Once the Hawker Siddeley P.1127 had proven the practicalities of V/STOL flight with its revolutionary Bristol Pegasus engine and rotating thrust nozzles, the British Government placed contracts with Hawker for 9 further developed evaluation aircraft, to be known as the Kestrel FGA.1.  Procured with financial support from the US Mutual Defence Assistance Programme (MDAP) plus other NATO finding, the aircraft incorporated as many improvements arising from the P.1127 programme as could be adopted in the timeframe. A large airframe, larger fully swept wings and a larger tail accompanied a Pegasus Mk.5 engine with significantly more power.

In October 1965, a Tripartite Evaluation Squadron, consisting of pilots from the UK, US and West Germany, began to explore the operating parameters and concepts that V/STOL brought.  Flying out of RAF West Raynham and RAF Bircham Newton, they determined that short take-offs and vertical landings were the optimal pattern for a typical exercise.  Development of the aircraft's intakes continued during this period, with the previous inflatable rubber intake lips eventually being ditched for fixed flared metal intakes, which were marginally less effective at low altitude and speed, but worked well in the hover (suction intake relief doors were added later to the Harrier intakes to improve the balance between hover performance and level flight).

The trials were successful and six of the 8 remaining aircraft (one was lost during the trials) were taken to the US for further testing, including 2 that used by NASA.  Although the West Germans decided not to progress, the 2 remaining UK aircraft became the patter for the first P.1127 (RAF) aircraft that would eventually (after cancellation of the preferred P.1154 supersonic aircraft) become the remarkable Hawker Siddeley Harrier.

 

Building a Kestrel FGA.1:


The P.1127 and Harrier hold a special place for me;   my first ever model kit was an Airfix P.1127 (built for me by my dad) and on the day I undertook my Admiralty Inverview Board to join the RN, HMS INVINCIBLE had just commissioned in Portsmouth and was berthed just outside Portsmouth Harbor Station when my train arrived, with brand new Sea Harriers on deck; I served in  HMS HERMES and HMS ILLUSTRIOUS (with Sea Harirers) and HMS INVINCIBLE was there, decommissioning, once again with Sea Harriers on deck, when I left the RN.  


Not surprisingly, I have a large collection of built models of P.1127s, AV-8As, AV-8Bs, Harrier GR.1, GR.3, GR.5, GR.7 and GR.9s, plus even a vacform P.1154!  Nevertheless, it seems I haven't built a Harrier of any type since 2021!  A shocking neglect on my part, so maybe this year will see a few more added to the collection (there are certainly plenty in the stash).


What I don't have though, built or unbuilt, is a model of the Hawker Siddeley Kestrel FGA.1, the half-way house between the P.1127 and the Harrier proper.  There have been a few resin kits over the years, but not widely available.  That said, no doubt a new Airfix one will appear shortly, just because I have started this project!




Link to many more Harrier models on my Harrier pages

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The Kestrel is different from the P.1127 in many ways.  It is nearer to the Harrier, but still has quite a few details carried over from the P.1127.  Taking a Fujimi AV-8A kit as my basis, I hope to address as many of these as I can:


The main visible difference in the Kestrel is a larger swept wing, very similar to the Harrier, but with shorter tips, with the outrigger wheels right at the tip.  The number and size of the vortex generators varies between individual aircraft and timespan.  Early Kestrels have no sawtooth on the leading edge.


The engine air intakes are larger than a P.1127, much nearer to a Harrier, but angled back and flared out in the same way as the rubber P.1127 intakes (early Kestrels had the rubber intakes to start with) and without the rounded splitter plate (which isn't actually a splitter plate because it doesn't have a gap).  There are no auxiliary intake doors around their outer edge.


The fairing for the nozzles is more defined, without the blending into the upper surfaces seen on the Harrier.   Indeed the whole fuselage area around here is quite different.


The hot nozzles are bigger than a P.1127.  However they (and the cold nozzles) have many more louvres than a Harrier.

Early Kestrels have the same shape tailplanes as the P.1127, although later ones moved to the cranked leading edge design seen on the Harrier.  The first few Kestrels started off without the Harrier's inner end plates, although they did have the characteristic Harrier anhedral.  


A RAM Air Generator for the hydraulic system is seen extended in most pictures of Kestrels on the ground.  The Harrier has this, but it doesn't seem to be deployed as often.


The Pitot is fitted on the fin, (like the Sea Harrier FA.2, but bigger).


The main undercarriage door doubles as an airbrake, like the P.1127.


Unlike the Harrier, there is no intake at the front of the fin.


The tip of the nose carries a small camera.

Background Image - A restored Kestrel at the RAF Museum, Cosford

Above: the First Generation Harrier family from left to right, P.1127, P.1154, Kestrel FGA.1, Harrier GR.1, AV-8A, AV-8S, Harrier GR.3, Sea Harrier FRS.1, Sea Harrier FA2.

Link to Part 2 - HMS DARING

Link to Part 2 - HMS DARING (D05)

Above:  XP984 at the Brooklands Museum.  This aircraft was the last P.1127 to be built and featured the swept Kestrel wing for the first time.  It was later fitted with the Pegasus 5 engine to become the Kestrel prototype.  

Above: Kestrel XS695 at the RAF Cosford Museum in TES markings

Above: P.1127 XP980 at the Fleet Air Arm Museum, Yeovilton (fitted with a Harrier wing)