Flight test: Hawker Sea Fury T.20
PUBLISHED: 13:12 11 March 2021 | UPDATED: 09:28 12 March 2021
Photo Copyright Gavin Conroy
Dave Unwin only managed a few minutes of his test flight in the Sea Fury, but it was long enough to confirm his love for this fighter
“Duxford, Sea Fury - Mayday, Mayday, Mayday,” Eskil Amdal’s calm, crisp call belies the seriousness of the situation. Big blobs of oil are spattering across the windscreen and smoke is streaming from the cowling, while a glance at the instruments confirms what I already know: the oil temperature is on the redline and the oil pressure is collapsing. The engine is starting to stutter as I hurriedly tighten my harness. And the day had begun so well...
In fact, the day had begun exceptionally well, because I was going to get my hands on an aeroplane that’s always fascinated me; the Hawker Sea Fury. There’s something about this big navy fighter, possibly because it’s related to one of my all-time favourites, the Tempest V. Or perhaps because it crosses over between the last of the ‘pistons’ and the first of the jets. Or yet again maybe it’s the fact that it was the last piston-engined fighter operated by our Services. Whatever the reason, this aircraft has always had a hook (or shall I say a tailhook?) in me.
So, when the opportunity arose to fly in one I didn’t hesitate, and on a lovely August morning Rob Stewart of aircraft broker Eagles 11 introduces me to Shaun Patrick, who owns Sea Fury T.20 Invincible and P-51 Mustang ‘The Shark’.
Trainer with a history
As we walk out to Invincible, I realise just how big it is. Parked near a Spitfire and Shaun’s Mustang, it towers over both and is also twice as heavy! As we commence a walkaround Shaun provides a potted history of the T.20, which is essentially a two-seat, partly-navalised trainer version of the Fury T.61. As the Royal Navy operated over six hundred Sea Fury fighter-bombers between 1947 and 1955, a two-seat trainer made sense, and the Fleet Air Arm procured sixty between 1950 and 1952.
Many of the differences between the single and two seat variants are quite subtle, and include very small increases to the surface areas of the tailplane and elevator. Unlike the single-seaters, the T.20’s tailwheel does not retract, and each wing had one of the two 20mm cannons removed to allow for the installation of oxygen bottles (in the port wing) and additional avionics (in the starboard).
Despite this being the general configuration, sharp-eyed readers will have already spotted that Invincible appears instead to have two cannons in each wing, and that its tailwheel does retract. In fact there are several significant differences between the WG655 that left Hawker’s Langley factory in 1951 and the aircraft as it is today. Its original Bristol Centaurus 18 engine and five-blade Rotol propeller have been replaced by a Pratt & Whitney R-2800 ‘Double Wasp’ and a massive four-blade Hamilton-Standard constant-speed prop. This is the most common of the big radials by a country mile, an incredible 125,334 being produced between 1939 and 1960. It powered dozens of different types, including fighters like the F4U Corsair, bombers such as the A-26 Invader, airliners such as the Constellation and even helicopters like the Sikorsky CH-37.
The specific engine model fitted to Invincible is an R-2800 CB3, also known as a ‘transport’ version. At 2,000hp it isn’t quite as powerful as the version fitted to the fighters (which produced up to 2,800hp) but it is, somewhat ironically, generally considered by the Americans to be much more reliable than the Bristol engine. Spares are unsurprisingly also much more plentiful, while the Centaurus’ sleeve valves require careful setting up. The propeller is from a Grumman Guardian ASW and is so huge it wouldn’t look out of place on a ship!
The Fury was developed from the Tempest, and the wing consists of two Tempest outer sections to which are bolted inner sections that mate at the fuselage centreline (instead of being attached to the side of the fuselage as on the Tempest). The cantilever wing is all-metal, of elliptical plan form and uses Hawker’s own proprietary aerofoil section. It’s constructed as a two spar-structure which is built in four main sections: the inner panels are rigged flat and carry the fuselage at four pick-up points, while the outer sections have a dihedral of five and a half degrees and fold upwards hydraulically.
Wonderful roll control
An interesting aspect of the wings are the ailerons. These are mass-balanced and of a modified Frise-type, but what is particularly noteworthy is that as well as having a trim tab they feature Hawker’s patented spring servo-tabs. As I soon discover these make control in roll surprisingly light, even at relatively high speeds.
Obviously I’ll be flying in the back seat but Shaun invites me to try the front cockpit for size, and smilingly asks if I’d like to use the metal stairs. I decline, as I want the full experience, although at one point I almost regret my impetuousness. If you look at the picture on page 55, you’ll note the red lines painted on the port side of the fuselage. These lead you to several spring-loaded foot- and hand-holds to help climbing up to the cockpit, and as I prepared to step over the canopy rail it suddenly occurred to me that if I slipped and fell, I’d probably break something – it’s a long way down! I shudder to think what it would’ve been like on the icy deck of HMS Glory as the carrier pitched, rolled and heaved its way across the Yellow Sea in a winter storm off the coast of Korea.
Having sat down, my first impressions are that the cockpit is quite snug for such a big machine, and that the field of view over the nose isn’t that bad when compared to some other aircraft that I’ve flown. Staying with comparisons (which, although odious, are sometimes unavoidable) the next thing to strike me is how ‘ergonomic’ it is. I’ve been lucky enough to fly several dozen aeroplanes designed in the 1940s and 50s, a time when the word ergonomic didn’t exist. Apart from the standardised blind flying panel, British cockpits are often the worst laid out, and sometimes the old joke about the designer simply tossing the various controls and instruments into the cockpit and installing them where they landed seems to have a grain of truth to it.
The Sea Fury is different. Its instrument panel is clean and uncluttered, the side panels for the various systems and sub-systems easily seen and reached, and the location of controls like the main fuel shutoff valve, trim wheels, tailwheel lock and undercarriage lever logical. The throttle lever is huge and has a vast range of travel, while the stick features the classic British spade grip (but no brake lever, as the original pneumatic brakes have been replaced by toe-operated hydraulically actuated discs from an F-106). Although with the original Centaurus prop rpm and mixture were regulated automatically, this aircraft now has separate levers for these vital functions. The only levers I couldn’t locate were for the cowl flaps and oil cooler, but Shaun explained these are automatically controlled by thermostats.
Orchestra of eighteen cylinders
After I’ve tried the front seat, Eskil arrives and, after a thorough briefing, we change cockpits and he brings the mighty motor to life. Starting something as big as a Double Wasp (it’s a 46-litre engine) is a truly visceral experience, and it takes a while for our eighteen cylinder orchestra to get ‘in tune’, but once it is−wow! The run-up isn’t rushed, as it takes time for the seventy-five litres (no less) of oil to come up to an adequate temperature for the prop governor to be cycled.
Eventually Eskil lines up on Duxford’s Runway 24L, locks the tailwheel, then smoothly and slowly advances the throttle while I gently follow through on the controls. Take off power is 48in of manifold pressure with the prop lever set for 2,800rpm, although I note the rpm is a couple of hundred revs below this as we start to accelerate. The sound is colossal and, as the airspeed starts to build and the rpm increase, there’s around two thousand of Pratt & Whitney’s finest ponies pulling. At about 100kt the Sea Fury slides into the sky, and as soon as we have a positive rate of climb Eskil selects the undercarriage ‘up’. It has a fairly low limiting speed and we need to have the wheels in the wells before we hit the 140 knot maximum allowed.
With the undercarriage safely stowed, Eskil makes a smooth but significant power reduction to 40in/2,400rpm, points the long, shapely nose to the north-west and hands me control. As per the briefing, I accelerate to 200kt and accept the climb rate this produces. The fuel flow has dropped from a tank-and-wallet draining 1,000 lit/hr to around 700. Still not inconsiderable, but careful power management in the cruise can get this down to around 290 lit/hr at 35in/2,000rpm for a IAS of 240kt at 6,000ft. The ‘max endurance’ power setting of 25in/1,800rpm gets the fuel burn down to as low (low!) as 200 lit/hr at about 180kt. There are no fewer than five internal tanks, two in the fuselage and three in the wings, for a total capacity of 909 litres.
Surprisingly smooth, incredible momentum
Now that I’m flying (although I know that Eskil is guarding the throttle and prop levers zealously) I can start to get a ‘feel’ for this awesome aeroplane. My initial impressions are twofold: it’s surprisingly smooth and there’s a strong sense of incredible, irresistible momentum. The smoothness may be because the engine is only turning at quite low rpm compared to the urgent thrashing of a Merlin−and the big radial’s really quite smooth for a piston engine−but the real sense is of being unstoppable.
Moving on to an assesment of the controls, I’m astonished at how light the ailerons feel (because of the servo tabs) and Eskil confirms that even at high speed the stick forces remain essentially the same, and are quite similar to the irreversible hydraulically-powered controls of the early jets.
After several turns of increasing steepness, I try a couple of rolls and again it’s amazing just how delightful the handling is. The elevator feels authoritative without being twitchy and the rudder well weighted−but it’s the ailerons I keep coming back to. They really are very light and overall the handling is profoundly impressive but I shouldn’t be surprised, it does represent the ultimate evolution of the piston-powered fighter.
For a look at slow flight, Eskil carefully reduces the power (engine management on big radials really is critical) while I pitch the nose up and start slowly bleeding the speed off. It takes a while to decelerate, but as the ASI’s needle starts winding counter-clockwise through 100kt there’s a subtle rumble through the airframe. I can’t quite believe this big, heavy fighter can fly so slow, but by 90kt the buffet is more insistent and the wing finally quits flying at about 88 with a slight wing drop. It’s still surprisingly benign and gentle for such a large fast aeroplane.
Eskil resumes control, accelerates and pulls up into a beautifully smooth loop. I’m hoping I’ll get the chance to try one, when Eskil asks me what my oil temperature gauge is indicating. It was nicely ‘in the green’ the last time I’d looked, but now it’s quite close to the red line, and when I relay this information to him, he confirms that his says the same and “we ought to start heading back.” Another glance at the panel and I see the temperature is still increasing and worse: the oil pressure is fading. The engine’s life blood is literally draining away, and although I can see the Duxford ‘super hangar’ in the distance, I already know we won’t make it. The motor’s confident roar has changed, and the vibration pulsing through the fuselage is no longer smooth but harsh and jagged. The Double Wasp is dying. Big blobs of oil are beginning to spatter the windscreen, smoke is streaming from the cowling and the engine’s starting to stutter. “Duxford: Sea Fury−Mayday, Mayday, Mayday.”
HAWKER SEA FURY T.20 - SPECIFICATIONS
Length: 10.57 m
Height: 4.83 m
Wing spaN: 11.70 m
Wing area: 26 sq m
Empty weight: 4,191 kg
Max auw: 6,441 kg
Useful load: 2,250 kg
Wing loading: 247.7 kg/sq m (52.32 lb/sq ft)
Power loading: 4.31 kg/kW (7.3 lb/hp)
Fuel capacity: 909 lit
Vne: 382 kt
Cruise: 240kt IAS at 6,000 ft
Stall: 90 kt
Climb rate: 4,000 fpm
Takeoff over 50ft: 500m
Landing over 50ft: 750m
Pratt & Whitney R-2800 ‘Double Wasp’ air-cooled 18-cylinder twin-row radial, producing 2,000hp (1,491kW) at 48in MP and 2,800rpm, driving a Hamilton-Standard four-blade constant-speed propeller
Manufacturer: Hawker Aircraft