Flight test: De Havilland Vampire T.11
PUBLISHED: 15:57 03 March 2021 | UPDATED: 15:57 03 March 2021
Keith Wilson 2020
An extra special flight test of a Vampire T.11 built in 1952; the last T.11 flying in the world & the last RAF Vampire still flying
Words: Bob Davy | Photos: Keith Wilson
Have you been to England’s de Havilland museum yet? If not, you need to. For a nice day out, start with breakfast at the Ace Cafe on the North Circular−the original ring road around London. It’s the place where café-racer motorbikes got their name in the ’50s (bikers racing from one cafe to another.) Then proceed north to the London Colney intersection of the M25. Sixty seconds from there is Salisbury Hall, which de Havilland made its base in the late ’30s and is now home to the original ‘wooden wonder’, the prototype Mosquito. (On one of the data plates at the museum is a quote from an admirer, calling the Mosquito ‘a nice piece of woodwork’.)
That aircraft is worth going to see all by itself, but there’s another wooden wonder too; the Vampire. It was the RAF’s second operational jet fighter (the first was the all-metal, twin engine Gloster Meteor). The Vampire’s forward fuselage used the same technology as the Mosquito and indeed the cockpit of the two-seat version was almost identical, before a requirement for ejection seats forced a redesign. The rudder profile is also similar.
Our test aircraft was built in 1952 with the original cockpit design, and was retrofitted with a newer canopy and bang seats later−look closely and you can see the join. In fact, WZ507 is not only the last T.11 flying in the world, but the very last RAF Vampire still flying. But what about the Vampire ‘firsts’: the first single-engine RAF jet, the first composite jet (wood, aluminium and plastic); the first 500mph fighter; the first jet to fly across the Atlantic (see ‘Atlantic wings’ box, p.38); the first jet to take off and land on an aircraft carrier (with Eric ‘Winkle’ Brown at the controls) and the first ex-military jet to appear on the civvy register in the UK (in 1980). The list is very long.
WZ507 is owned and flown by Mark Hooton, an airline pilot, a good friend and a Vampire devotee. And something else−an inspirational figure, showing us all how to run a warbird on a budget, doing whatever it takes. Mark is not particularly rich−he’s just ‘a doer’. He gets on with it when most pilots would baulk at spending ten per cent of their income on a hobby. (With Mark it’s... er, rather more than ten per cent.) I have followed his worldwide search for parts to keep the Vampire in the air−he is known to air museums around the globe. His house is like a shrine to the aircraft as well as being a workshop for it−there are spares, manuals and books everywhere. An air intake cowling on the floor in the living room, a compressor stage in the hall...
When Mark first joined a four-man group to buy the Vampire in 2005, he tells the story that before the aircraft even took off for the first time the group landed a repair bill that would buy a decent new car after the canopy came loose, bounced over the back of the fuselage and hit the tail. That was the last of three times it happened−two in previous ownership. Every landing costs £100 in rubber. And don’t mention fuel−the engine’s not called a Goblin for nothing. When the group started, you could get JET A1 for 8p per litre. Today it’s more like eighty. One by one, the members of the original group dropped out, but Mark stayed the course. He is too modest to own up to what the aircraft currently costs him to run per year and per hour, so I don’t ask. But we do contribute...
We meet up with Mark and his Vampire at Coventry Baginton airport just before Lockdown 2. As usual he has a few helpers, because you can’t get a Vampire out of a hangar on your own−and it needs a ground power cart to start it. This then has to be disconnected and the chocks removed. (Sorry, I should have mentioned: chocks are another essential−you can’t use the parking brake for start-up because it will deplete the air in the accumulator in two minutes flat. That means the air would have to be recharged again, the cycle repeating itself if the parking brake is left on. In other words, don’t use the parking brake at all, even when taxying out.) Operating a Vampire is neither for the faint of heart nor the impatient.
With all the preparations going on, I get to look around the aircraft for the first time in the ten years since I last flew in it. Not a lot has changed, if anything it’s in better condition: an aircraft seller would probably award it 9/10 on the outside and 8/10 on the inside. The ‘bonnet’ is open for the preflight: viewed from the side it looks like a cartoon character, a frog catching a fly or a yawning hippo. It makes me laugh looking at the wood poking through under chipped or worn paint on various seams, just like you would get in a Tiger Moth. And then I remember that the Tiger Moth design is only twelve years older−de Havilland were still building the wood and fabric skinned biplane when they went into production with what was then called the Spider Crab. Luckily someone must have ‘had a word’ and the name got changed to Vampire−which is still a slightly odd name, when you think about it. But then so is Spitfire (even designer Reginald Mitchell disliked that one). Hopefully this Vampire just sucks money, rather than blood.
Joining the jet set
Time to strap in. I climb the little ladder, which is hooked to the side of the cockpit (removing it is another job for the ground crew) then stand on the seat and climb down and in. The seats are the original bang seats and as such are fixed, fore and aft although they can be raised and lowered. Nevertheless, they are pretty uncomfortable for anyone over 5ft 10in and still require someone tall like me to fly in a slightly stooped, head-craning-forward position reminiscent of flying the Jet Provost, which I found contributed to air sickness at the time I flew them. The rudder pedals are adjustable though, and I end up in a bearable position, albeit a bit too close to the instrument panel than ideal−that’s what happens when bang seats get shoe-horned into a cockpit not originally designed for them.
The word ergonomic originated from Greek−‘ergon’ is work and ‘nomos’ natural laws−but you probably won’t find it in the 1943 Oxford English Dictionary. And you won’t find it in the Vampire cockpit. I literally don’t know where to look. Apart from all things black, it is also full of wasp-striped levers, knobs and dials saying to me “Don’t touch!” Like a Porsche 911, with its rev counter taking centre stage rather than the speedometer, the rpm and JPT (jet pipe temperature) gauges are in front of the vampire student rather than the artificial horizon. Fuel is carried in nine tanks but unlike the early Vampires there is only one fuel gauge with maximum showing as 2,540lb−around 330 gallons. Newer additions to the panel are a Dynon attitude indicator at the top of the coaming and an ageing GPS map on the right. Although I do what I am told to get the thing started, I can’t remember the detail despite the notes I took, and so am handing over to Mark here. “The Engine is started by an electric starter motor, which rotates it to self-sustaining speed in three stages−these are controlled by a clockwork timer. Like any light aircraft, the first thing we need is electrical power, so push in the ‘Ground/Flight’ switch on the lower centre of the instrument panel to Flight. When ready to start, push and hold in the starter button for two seconds−this winds and activates the clockwork timing sequence. After releasing the start button immediately start the chronograph. Current flows to the starter motor through the slow engagement stage and speed limiting resistors, and to the ignition equipment relay.
Initially the starter turns slowly to prevent damage to the drives in the engine. The steady “tick, tick” of the igniters can be heard. The two igniter plugs are mounted on combustion chambers two and fourteen. After four seconds the second stage begins and the starter motor increases speed. Introduce the fuel into the combustion chambers with the HP [high pressure] cock located adjacent to the throttle after checking you’ve 900rpm and no earlier than ten seconds in−the timing is important, to allow for the fuel accumulator to fill with fuel and pressurise. Typically, you will hear the engine light up and observe a steady rise in both RPM and EGT. Keep an eye on the fire warning light and for signals from the ground crew throughout! Observe the JPT 710˚C limit. After 30-40 secs the starter motor disengages automatically; if the RPM is greater than 1,500 the engine should carry on accelerating to idle at 3,000 and after a peak EGT of 600˚C, slowly drop to a steady 500. But if it’s less than 1,500rpm at starter disengagement, you will have to abort the attempt and close the HP cock. The most likely cause of problems with the start are external, for example the trolley acc batteries have discharged or disconnected.”
Thanks Mark! It’s about now that I realise the ground crew have buggered off for lunch and it falls to our friend Charles−who travelled up in the camera ship with us−to pull out the battery cable and kick away the chocks. We can’t hang around or we’ll start to melt the tar seams between the slabs on the concrete apron, and it’s here that Mark undergoes a marked change from laid-back Aussie to animated fighter jock, his hands flashing around the cockpit. According to a flight report in the ’40s (no doubt with the Official Secrets Act looming over the reporter like the sword of Damocles) preparing the Vampire for takeoff required pilots ‘to perform only six vital actions: setting the trim to neutral, opening the high- and low-pressure fuel cocks, activating the booster pump, setting the flaps, and retracting the air brakes.’ But it feels like, and is quite a lot more than that. I open the throttle slowly, the whistling noise of the Goblin rising sharply and with not much acceleration with respect to the noise increase, the Vampire lunges from side to side as I operate the handbrake lever on the stick simultaneously with bootfuls of rudder. Mark takes over to navigate us between some fencing then gives it back again and I’m doing better this time, feeding in the brake slowly and ‘blending’ the turn.
At low power settings the noise doesn’t seem to match the thrust and despite me having thousands of jet hours, it’s not at all instinctive how much throttle is needed to make the thing accelerate or slow down. When the throttle moves forward, all eyes in the cockpit fall on the JPT needle as it surges across the gauge towards the red line, the whistle inside and outside rising in pitch−nothing much changing to the scenery outside. And we can’t stop, say to take an ATC clearance, because we mustn’t run out of brake pressure−if the handbrake needs to be applied, then two minutes later we would have to go back to stand to recharge the system. Everything seems like hard work. (I’m not exactly selling it so far, am I?)
A tortoise on the runway...
We line up on the easterly runway, I slowly open up to 7,000rpm then, at Mark’s instruction, move the throttle twice as quickly, to 10,250rpm, (a maximum of 10,650 is available). Acceleration along the runway is... unimpressive. I still use the brakes up to fifty knots, at which point the rudders become effective, raise the nose at eighty and the Vampire flies itself off at 110, after using less than 1,000 metres of runway. The climb angle is as flat as I remember it, but the acceleration building now. Ensuring the rudder is centred, I squeeze the brake lever to stop the wheels spinning and select gear up before we reach 175kt. It comes up in three seconds flat and it’s important to raise the wheels quickly if drop tanks are carried, because aerodynamic interference between them and the doors means it’s impossible to get the gear up at higher speeds. I then let the acceleration continue past 200kt as I bank right to close the gap between us and the camera ship which took off two minutes before us.
The ailerons are featherlight and control harmony between ailerons, elevator and rudder a perfect 1:2:3 ratio in their weighting. I’m not having to work at all hard at this point but that’s not going to last for long.
Open-top high-performance aircraft with two seats suitable for use as camera ships aren’t ten-a-penny, which is why we are now coming into formation with a Piper Aztec with its over-wing emergency hatch removed. The problem is that we are now pulling back to idle on the power to slow down to 150kt, and the first time I inevitably overshoot the camera ship slightly, then can’t do anything about it. We can’t go much slower and they can’t go any faster, so we both sit there until I introduce an S-turn to drop behind and then try to close for a better position. The second attempt I give to Mark because for me it’s like milking a nervous mouse, whereas Mark puts us in the vicinity of the camera ship twice as fast. After that, I have it again and it’s working out better, the learning curve flattening and everything going well−as you can see from the pictures−but it all takes time and we don’t have much of it, because even down at 150kt that Goblin is gobbling an average of 30lb of fuel per minute. Yes, 3.5 gallons per minute−there are aircraft flying today which use that much per hour. To put it into a 21st century perspective, the latest Boeing 737 and Airbus A320 engines are ten times more powerful than a Goblin, and yet each burns about the same while carrying 200 passengers at 500mph.
As we get closer, I’m pulling the power back and Mark’s telling me “avoid 8,200 to 8,600rpm”. Ironically that’s the rpm range where the power would be ideal to gently close the gap, but it’s also in the range that would have the engine destroy itself if we left it there. Don’t worry, it’s marked as a red band on the rpm gauge so you can’t miss it... unless your eyes are outside, looking at a camera ship. I’m pleasantly surprised that I can use full rudder with a bit of opposite aileron to get those ‘head on’ shots when flying behind the Aztec. Some jets would protest but not the Vampire−docile is not an adjective normally associated with jet fighters but it has to be said that the Vampire is−at low power and speeds anyway (I’ll eat my words in a few minutes time). All in all, it’s a tough twenty minutes and I’m relieved when photographer Keith tells pilot Tim to radio us to knock it off.
... A hare in the sky
Now it’s time to play, and I start with the inevitable aileron roll, pulling the nose up just five degrees instead of the more usual twenty to thirty, then checking the pitch and using full aileron for the roll. There is no, repeat absolutely no, adverse yaw. At 250kt the Vampire goes around in about six seconds and I check, wings-level then pull up into a big wing-over to the right. You can stall-turn a Vampire but we don’t have the airspace−so a wing-over it is, followed by a loop entry at 300kt and a looooong 4g pull all the way round. That’s the thing with jets−the figures are huge and the g goes on for ages. But the uncomfortable seat is now forgotten and I’m having a whale of a time.
This aircraft is as smooth as a video game, every manoeuvre long and effortless, one county at a time. Then I go and spoil it by saying “OK show me what it can do”. That’s a bit like asking European Freestyle Aerobatic Champion Gerald Cooper to show you what his latest unlimited aerobatic trainer can do, or being offered a lap round the racetrack with Louis Hamilton (an offer I would decline). All of a sudden, we are in a high-g turn, the wings way past vertical, and we are pulling towards the ground, which is rushing up fast. It feels too late to get out of it, like going past the braking point before a turn on the track. I am moved to ask “you OK?” just to make sure that Mark is still conscious, but I can see he is, and we snap out of the roll wings-level at 500ft and 250kt before snapping into a wings-vertical turn the other way for another 6g. This carries on for several minutes.
At one point I see 400kt on the ASI and we are still accelerating. What about compressibility? The 440kt artificial red line imposed by the CAA means Mark never gets anywhere near it, but a gentle wag in yaw tells him when it’s approaching. He has never experienced the next bit: the wild +3/-1g pitch oscillation they say you see at speeds approaching Mach 0.8.
Now we are down low again and 250kt. A disused airfield flashes past the right window but I have no idea which one, because I don’t know where we are any more. (Evidently this was a fly-past for a friend and he’d called for it on the radio−but I didn’t hear). It’s over as fast as it started and Mark is pointing to Coventry with his finger on the ancient GPS. I’m so disorientated I think we’re heading north (I never did find the compass) and only when Mark says ‘we’ll join long finals’ that I realise we’re heading east and already lined up on the runway thirty miles out. Blimey.
Mark points at the fuel gauge - we’ve used the 800 lb we bought him and only have 700 left. It really is time to go back. I close the throttle and the aircraft is predictably slow to decelerate. As it does, I have a moment to ponder: could you actually go anywhere in this aeroplane? The answer is yes−but you need thin air. An ideal altitude would be 10,000ft-plus, at 300kt IAS and up to 400 TAS, still burning 35 lb per minute. Without drop-tanks Mark rarely ventures more than 250nm between top-ups.
The airfield looms ahead, the speed is back below 175kt so I drop the gear, closely followed by the first stage of flap, the next at 160, and final stage at 140. Suddenly we’re very draggy and I’m pushing the power up, through the bad bit then more, more and more, the engine screaming. “More!” urges Mark and promptly raises the gear, then lowers it again as the ASI finally responds. Short final is flown at 120kt, over the hedge at 110, the ASI fluctuating due to aerodynamic interference around the pitot probe. The landing itself is very straightforward, nose held high for aerodynamic braking. Now we are looking at the brakes again−have we got enough pressure left to taxi in safely? Yes, is the answer−but the personal pressure’s not off until we swing onto the apron and shut down as Charles kicks the chocks in. Phew!
Since its first flight in 1943 at the hands of Geoffrey de Havilland junior−the founder’s son−the Vampire has held the flying world’s attention and affection. Price when new was £29,000−around £1m in today’s money. What this one is worth now is anyone’s guess. A total of 3,268 Vampires of all types were produced, and very few are left flying today.
Since Shoreham, this T11 hasn’t appeared in a British airshow−so opportunities to see it fly are few and far between. But you can come to Coventry and see it, or fly it yourself with Mark. Now I know what I’m in for, I want go and do it again.
In July 1948, six Vampire F.3 aircraft from No 54 Squadron, RAF Odiham, completed the first transatlantic crossing by jet aircraft. The Vampires left Stornoway on Monday 12 July and made the 2,203 mile ocean crossing in a flying time of eight hours and eighteen minutes. The trip was accomplished on three legs. The first, from Stornoway to Meek’s Field, Iceland (662 statute miles) took 2 hours and 42 minutes; the second leg from Iceland to Bluie West 1, Greenland (757 miles), was completed in 2 hours 41 minutes; and the final leg from Greenland to Goose Bay, Labrador (783 miles) took 2 hours 53 minutes. The Vampires cruised at between 25,000 and 32,000 feet - and occasionally higher - along tracts of the upper air over the Atlantic Ocean which were then almost unknown. The trip provided a wealth of information and experience which was to prove particularly useful to the future transatlantic civilian jet traffic.
To comfortably complete the transit, the formation required good visibility at both departure and arrival points, along with favourable winds at 25-30,000ft. However, the formation suffered considerable headwinds, up to a recorded 207mph at one point, some of the weather fronts encountered extending up to between 35,000 to 40,000 feet, while fog over the mountain-locked fiords added to their woes. The arrival of the first of six Vampires at Goose Bay at 9:25pm local time (1225 GMT) on Wednesday 14 July, was amid rain squalls driving across the airfield. Within a short time, all six aircraft had arrived safely, proving that ferrying a jet squadron across the Atlantic, along with its support crew and ground equipment (in piston-engine transport aircraft) was a feasible proposition.
The flying duties were shared among nine pilots from 54 Squadron, divided into three sections, Blue, Red and Black. The Stornoway-Iceland first leg was flown by Blue and Black sections, the Iceland-Greenland second leg by Blue and Black sections, while the final Greenland-Labrador section was completed by Red and Black sections – thereby ensuring that each pilot completed two legs of the transatlantic crossing.
At Goose Bay the squadron was given a reception by the resident Royal Canadian Air Force (RCAF). Also there to meet them was Colonel David C Schilling of the USAF’s 56th Fighter Group, who was waiting to lead sixteen Lockheed F-80C Shooting Star aircraft in the opposite direction, over the route the Vampires had just taken. The P-80C aircraft were en route to Germany for a 45-day detachment as part of Operation Able Fox 1, in response to the Soviet Union blockading Berlin.