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RAMP RAMBLINGS 17

RAMP RAMBLINGS………..By Keith Bradshaw. All photos by the author and Steve Jeal unless noted.

Hello and welcome to the latest edition of Ramp Ramblings. As promised last month we will continue our look at one of the many anniversaries we are celebrating this year with a piece on the BAC 1-11. March 4 sees the twenty-fifth anniversary of the delivery of our BAC 1-11 to Duxford and August of this year will see the fifty-fifth anniversary of the types first flight. Believe it or not, one of the 244 built is still in operation with Northrop Grumman in the USA. Used for flight testing of various avionics including the radar for the new F35 STOVL fighter that is going to equip the RAF and Fleet Air Arm. Northrop Grumman plan to fly on this remaining example until 2019/20 depending how long it takes for the replacement CRJ700 to be modified.  

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Photo : Wikipedia

The Northrop Grumman BAC 1-11 radar test bed being prepared for another test flight.

So back at the beginning of the story, the BAC1-11 as we know it was originally a 1950s Hunting design and following that company’s merger into the British Aircraft Corporation it became the   BAC 1-11 in 1961. British United were the launch customer and the prototype made its first flight from Hurn (Bournemouth Airport) in August 1963.

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Photo : ClipperArtic

British United were the launch customer for the BAC 1-11 and it was this type of aircraft that took the airline into the jet age.

At the controls was test pilot Mike Lithgow, who held the world speed record 1953 in a Supermarine Swift at a speed of 735.7mph. Sadly Mike and the entire test crew were to lose their lives a few months later when the prototype BAC 1-11 G-ASHG crashed on Salisbury plain after entering a super stall from which there is no recovery. Little was known of this phenomenon at the time and it was as a result of this crash that much more research took place, we will look at the super stall later in this edition of Ramp Ramblings. Despite this set back the programme continued and with a healthy order book of 60, before the first aeroplane had even rolled out of the hangar, things were looking good for the project. Orders had come in from all around the world including the USA, with Mohawk, Braniff and American Airlines all placing orders.

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Photo : RuthAs

American Airlines were one of a number of US operators of the BAC 1-11.

The first aeroplane was delivered in January 1965 to launch customer British United. Orders continued to flow in with BEA placing an order for a number of the larger 500 series version. The BEA aircraft were unusual in that the company insisted the cockpit had the Smith’s Attitude Director and Flight Compass fitted as BEA had on the Trident so that the same flight crews could operate both aircraft. The CAA however had other ideas and both fleets kept their own dedicated flight crews. Our example G-AVMU was one of 18 ordered by BEA and first flew in January 1969, these were the first of the longer 500 series aircraft built. BEA based its 1-11 fleet initially at Birmingham but a number of them were stationed in Berlin to operate the internal German routes as before German unification, only US/French/British airlines could operate into West Berlin. When MU arrived at Duxford it had flown over 40,000 hours. Following a repaint a couple of years ago it looks spotless in its British Airways ‘Landar’ paint scheme.

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VMU of the British Airliner Collection at Duxford after its repaint.

BAC 1-11’s found customers in the corporate and military worlds as well, in fact the last BAC 1-11 to operate in Europe was the Qinetic 500 series flying on research flights from Boscombe Down. This aircraft eventually retired to the aircraft museum at Newquay Cornwall.

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Photo : Adrian Pingstone 

Omani Airforce VIP transport, one of many BAC 1-11s operated by the world’s military.

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Photo : Aero Icarus

One of the BAC 1-11s operated by Romanian airline Tarom at Zurich in 1995.

The production line was moved to ROMBAC in Romania where it was planned to build a large number of aeroplanes but due to the political situation at the time only a few were built before all production was stopped in 1991, a total of 244 1-11s being built. 

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Photo : RuthAs

One of the smaller UK operators was Autair, with one of their examples here at Manchester. Autair was later renamed Court line and their 1-11 fleet (now 500 series) were painted pink, green, orange and light blue.

In the UK a large number of operators flew the BAC 1-11 such as Laker, BUA, Air UK, Caledonian, Dan Air, BEA/British Airways, British Midland, Court Line, Monarch and many more.

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Photo : Pedro Aragao

One of the more colourful operators was Air UK.

By the early 1990s in the UK only European and British World operated small fleets of the aeroplane. It was indeed a European aircraft G-AZMF that operated the last ever commercial 1-11 flight in Europe in 2002.

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  Photo : Pedro Aragao

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Photo : Pedro Aragao

One of the last UK operators was European who operated holiday flights from their base at Bournemouth.

When new noise regulations came into effect in Europe,  the 1-11 could not meet the requirements and most of the remaining airworthy examples were stored, scrapped or sold, many to Nigeria which had become a haven for the type with over 50 examples registered there.

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Photo : Pedro Aragao

One of the many BAC 1-11s operated in Nigeria before the fleet was grounded.

However after a number of crashes the entire Nigerian fleet was grounded. Aeroplanes can still be seen dotted around the world in the long grass slowly decaying away but the Northrop Grumman example is the last airworthy BAC 1-11 in the world still flying 55 years since the types first flight.

So that was our anniversary spot looking back on the 1-11, now for some news from Duxford. Following our success with the Hurricane repaint the IWM were suitably impressed and asked us to clean their TSR-2 in Airspace. Over a period of two days DAS volunteers dusted and washed the aeroplane down using de-mineralised water to bring the white anti-flash paint scheme back to looking something like it did when it left the factory at Warton all those years ago. For those who like to know these sort of things TSR-2 stands for Tactical, Strike, Reconnaissance, Mach 2.

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TSR-2 getting a good dust and wash.

Not content with cleaning a ‘little’ plane we then went on to start our annual dust and polish of the airliners in the hangar. Hermes, York. Comet and Concorde have all now been dusted and polished and are ready to start the new visitor season looking spick and span. Down at the military vehicle wing in the Land warfare hall, DAS volunteers are working hard to get a recently acquired Douglas aircraft tug back into running condition. Once this is done we will be able to move even the largest of our airliners without difficulty.  We actually obtained two tugs one as a runner and one as a static exhibit. This is in the DAS workshop and will require some extensive fettling to bring it up to scratch. Also in the workshop a number of volunteers have been hard at work making packing cases and sacks to use on the York as part of our Berlin Airlift themed display to be launched later this year to commemorate seventy years since the start of the Berlin Blockade.

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Volunteers in the workshop working on the ‘static’ aircraft tug we have recently acquired.

After the grand job that was done on the pump-up servicing platform volunteers are now also working on repainting tow bars and various other access steps ready for the new season ahead. The IWM have kindly offered us a couple of short term ‘slots’ in the conservation hangar for aircraft repainting. Our plan is to use the first of these slots for the Herald, to enable the wings to be repainted as this is not possible outside during the winter. This will then allow the restoration to continue with the refitting of the flaps. The end is in sight for this mammoth rebuild which hopefully will be finished sometime this year.

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When the Herald wing is repainted we can then reattach the flaps and ailerons making a whole plane again !

As we have not had a Technical Titbit for a while, I thought we would follow up on the earlier story about the loss of the BAC 1-11 prototype with a look at The super or deep stall and its effect on T tailed aeroplanes.  The tragic loss of G-ASHG and its crew back in 1963 was probably not the first crash due to this problem but it was the most documented with the crew giving a running commentary as their plane fell to earth. Brave men indeed. To understand this phenomenon we must first look at what a stall is. Lift as we all know is generated by the aerofoil shaped wing and one of the basic theories for lift is that the greater the angle of attack (this is the angle between the on coming air and the wing  the greater the lift. In other words the more you tilt the leading edge of the wing up into the airflow the more lift you get.

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Diagram from Wikipedia showing how as the angle of attack increases towards the stall the airflow can no longer flow smoothly over the wing and becomes separated from it causing the wing to stall.

 However, like all good things there is a limit at which the air can still flow smoothly over the wing. If the angle of attack is too great the oncoming airflow will break away from the wing surface and the wing will obtain the flying qualities of a manhole cover and fall out of the sky (with the aeroplane attached !) This is when the wing is said to have stalled. In normal operations this situation is unlikely to occur but if the aircraft is at low speed (eg. just taken off) and the pilot pulls the nose up without sufficient engine power it is unlikely to climb but just continue on the same flight path with an ever increasing angle of attack which will eventually lead to a stall. On a normally configured aeroplane, for example, one with a low tailplane, as the aeroplane drops towards the ground in a flat attitude there is still a flow of air over the tail plane and elevators. This is good news as all the pilot has to do is push the stick forward and the plane will respond as normal and go into a dive. As it does the oncoming air is now flowing smoothly across the wing, lift is restored, pilot levels plane and all retire to the bar for a stiff one !

However on a T-tailed aeroplane once the stall is entered and lift is lost, as the plane sinks towards the ground the tailplane and that life saving elevator has no air flowing over it, as due to the relationship between the positions of the wing and tailplane, the wing blocks the airflow over the tail. Once a T tailed aircraft is in a stall there is no escape.

So what can be done? All aircraft have a stall warning system, so if the pilot immediately responds to that there will be no problem. It was this stall warning system that the BAC 1-11 crew (and a few years later a Trident crew) were testing when their aircraft went beyond the warning position and into the full stall. Remember, this problem affects all Ttailed aeroplanes not just the 1-11 and Trident.  Across the pond both Boeing (727) and Douglas (DC9) also had the same problem. Their answer was somewhat laid back as they considered that along with a stall warning system the only other safety device would be a decal saying ‘do not stall this airplane’. This wasn’t enough for the ARB/ CAA and they insisted on a fully automatic stall warning and recovery system to be fitted to any T-tailed aeroplane on the British register. In fact when Dan Air bought some second-hand Boeing 727s it cost them around £1m per aircraft to modify them with a stall recovery system.

Let’s take a look at the Trident to see how De Havilland coped with this demand from the ARB/CAA. From what we saw earlier the beginning and entry into the stall is all related to the angle of attack. So what the manufacturers did was install devices which could measure this angle. Known as AOA probes or stall vanes these are the little wings or wind vane type sensors you will see on the side of the forward fuselage on all airliners.

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Photo : Alan Wilson

This view of the De Havilland Museum’s Trident 2 fuselage shows clearly one of the stall vanes within the red disc just forward of the door. This acted like a wind vane and always aligned into the oncoming airflow regardless of the fuselage/wing attitude. The difference between the two is the angle of attack.

To put it in simple terms there are switches inside these vanes that will trigger the stall warning at a certain angle of attack and then activate the recovery system at an angle of attack a safe distance from the stall. On the Trident the stall warning device is a motor attached to the control column with an off- set weight on its shaft. When the motor runs, at the stall warning point, the column vibrates like an out of balance spin dryer. If the pilot chooses to ignore this and continues to pull the aeroplane nose up and thus increase the angle of attack, the recovery system (known as the sticker pusher) will operate. That consisted of a high pressure air bottle driving a ram which was attached to the control column and would quite literally push the column out of the pilots hands and put the aeroplane into a dive to recover from the impending stall.

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Photo : Nimbus227

Trident 2 cockpit showing the stall recovery system dump handle (Tiger’s Tail) circled at rear of pedestal.

Like all systems which can affect the control of the aeroplane there was a manual override fitted called the Tiger’s tail. This is a black and yellow striped handle at the rear of the centre pedestal. Look out for it next time you visit the Trident. If this was pulled, all the high pressure air in the stick pusher bottle would be vented overboard and the sticker pusher would be inhibited. It was the Captain pulling this handle that prevented the stall recovery system from saving the Trident that crashed near Staines killing everyone on board. There we have it, a quick walk through the Super or Deep stall and how the manufacturers dealt with it and made flying safer

Well that’s about it for this month just to finish by saying April this year would have seen 50 years of Monarch who started flights in 1968 with a Britannia. Sadly as we know Monarch folded last year one year short of that milestone.

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Thanks to Tim Ainsworth, of the OVT restoration Facebook group. This is what the 50th Birthday of Monarch could have looked like!

But an airline that did make its 50th Birthday, and is also represented here at the British Airliner Collection, is Aurigny Air services. Who in March 1968 first started operating flights in the Channel Islands, a service they still offer today along with flights to/from the UK mainland and Europe. Next time we will hear the story of the Geordie Yellow Peril. Intrigued? Then don’t miss the next ramp ramblings.

Bye for now Keith.

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The two VTs celebrate their airline’s 50th birthdays this year.