Trevor Egginton
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Trevor Egginton
That lovely man ,Trevor Egginton ,passed away suddenly last Sunday.
Ex Royal Air Force he eventually became CTP for Westland Helicopters and achieved fame in this select world by setting the current absolute world speed record ...in 1986! He visited the record breaking Lynx helicopter only recently at the Helicopter Museum and shared his story with a select audience. Great loss.
Ex Royal Air Force he eventually became CTP for Westland Helicopters and achieved fame in this select world by setting the current absolute world speed record ...in 1986! He visited the record breaking Lynx helicopter only recently at the Helicopter Museum and shared his story with a select audience. Great loss.
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Ex Westlands CTP RIP
I heard some sad news today
Trevor Egginton has passed away after a heart attack.
You may remember him as the Chief Test Pilot of Westland Helicopters who Piloted G-LYNX to the world speed record in 1986 and Captained the first flight of the EH101 in 1987
Trevor was an Ex RAF pilot who flew (amongst other types), F86 Sabres before moving on to helicopters. He was heavily involved in Sea King and Lynx development in Yeovil.
Further information to follow
DM
(also posted in Flight Testing)
Trevor Egginton has passed away after a heart attack.
You may remember him as the Chief Test Pilot of Westland Helicopters who Piloted G-LYNX to the world speed record in 1986 and Captained the first flight of the EH101 in 1987
Trevor was an Ex RAF pilot who flew (amongst other types), F86 Sabres before moving on to helicopters. He was heavily involved in Sea King and Lynx development in Yeovil.
Further information to follow
DM
(also posted in Flight Testing)
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A marvelous pilot, and a legend. Trevor Egginton signed a print of his world record flight that I proudly display on my wall. I shared a glass of wine with Trevor and Jerry Tracy at Westland once, on the 5 year anniversary of that great flight. He will be missed, RIP Trevor.
Do a Hover - it avoids G
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For those that don't go to the Flight Test forum:
His speed record of 400.22kph/249.09mph was set on 11 August 1986 and was for an ordinary helicopter (nothing other than the main rotor to pull it along) and still stands. It was achieved during the BERP (British Experimental Rotorcraft Programme) of those days.
Among other things the BERP programme looked at blades with a wide chord at the tip. The wide chord (and thus lower aspect ratio) gave a larger stalling angle (to counter retreating blade stall) and allowed an increased mach number (before shock formation) for the advancing blade thanks to the reduction in the thickness chord ratio at the tip.
JF
His speed record of 400.22kph/249.09mph was set on 11 August 1986 and was for an ordinary helicopter (nothing other than the main rotor to pull it along) and still stands. It was achieved during the BERP (British Experimental Rotorcraft Programme) of those days.
Among other things the BERP programme looked at blades with a wide chord at the tip. The wide chord (and thus lower aspect ratio) gave a larger stalling angle (to counter retreating blade stall) and allowed an increased mach number (before shock formation) for the advancing blade thanks to the reduction in the thickness chord ratio at the tip.
JF
JF - you do it again. I am not a rotary pilot, but very interested in helicopters. A mate mentioned the record the other day and asked why a helicopter could not fly as quickly as a conventional aeroplane. I took about half an hour to explain it badly. Would that at the time I had had the benefit of your succinct and erudite explanation. I will pass it on to him. Many thanks
W
W
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There are two conspiring physical relationships that reduce the maximum forward speed for helicopters:
1) Retreating blade stall. The blade that is sweeping downwind during its journey around the mast (the retreating blade) sees its airspeed reduced by the aircraft's foward flight speed. In a hover, the blade tips are revolving at about .7 Mach, 450 knots or so. When the helicopter is traveling forward at 150 knots, the retreating blade tip has slowed to 300 knots or so, a very slow speed for such a thin, low area wing. Of course, half way toward the rotor hub, the blade's section is flying at almost backwards, and so is quite stalled. This retreating blade stall raises drag and power tremndously, and serves as a practical limit. Since control of the helicopter relies on adding lift to that retreating blade when a roll command is given, one of the signs of retreating blade stall is a tendency of the aircraft to roll to the retreating blade side.
2) Advancing Blade Mach - The advanicing tip sees an increase in its speed so that the 450 knots in a hover plus 150 knots of aircraft speed make it experience about 600 knots, almost Mach 1. Thus, transonic effects drive the advancing blades experience, and raise havoc with that blade's aerodynamic loads. Think of the problem the way the blade sees it, about 5 times a second it goes from Mach1 to stall and back again!
The way the Lynx record was set was a very intelligent application of several factors:
1) The blades were quite wide for the job, less practical for the hover (blade width robs hover performance) but just what is needed whan only a small segment ot the blade is lifting out there at 200+ knots.
2) The blade tips were carefully shaped to help transonic drag, so the advancing tip paid less of a price than a regular blade.
3) The excess engine power that was available was used in jet thrust by shaping the engine exhausts to achieve extra thrust, which relieved the rotor of that chore and helped boost the speed. As rotor thrust is "wasted" pulling the nose down and pulling the helicopter through the air, less is available to hold the aircraft up.
How do we get speed today? Three different ways:
1) Compounds like the X3 use power, props, wings and wide blades to get speed. It is no wonder that the X3 (built with the fuselage of an EC-155 at about 12,000 lbs) uses the drive train of an EC 175 and the engines of an NH-90 to do the job.
2) Tilting rotors and wings can do the cruise task, where the rotors no longer lift, and the wing does it all. The V-22 and 609 are examples of totally practical tilt rotors. Note that power still plays a part, they need about 50% more power than a pure helicopter of the same range and payload, but easily fly 100 knots faster.
3) Rigid coaxial rotors - where the retreating side's woes are ignored, and the pair of advancing blades, one on each side, do all the real lifting work. The X2 is an example, where the rotor is slowed down in high speed flight so tip mach isn't a problem, and the retreating blade has its angle of attack reduced to reduce drag and let it loaf along. The prop pushes the aircraft forward, the rotor lifts in near-autorotation, and the whole thing has reasonable efficiency and high lift/drag, albeit with the complexity of a coaxial rotor and prop. Few coaxials can go this fast, the rotors must be very rigid to permit post stall flight.
1) Retreating blade stall. The blade that is sweeping downwind during its journey around the mast (the retreating blade) sees its airspeed reduced by the aircraft's foward flight speed. In a hover, the blade tips are revolving at about .7 Mach, 450 knots or so. When the helicopter is traveling forward at 150 knots, the retreating blade tip has slowed to 300 knots or so, a very slow speed for such a thin, low area wing. Of course, half way toward the rotor hub, the blade's section is flying at almost backwards, and so is quite stalled. This retreating blade stall raises drag and power tremndously, and serves as a practical limit. Since control of the helicopter relies on adding lift to that retreating blade when a roll command is given, one of the signs of retreating blade stall is a tendency of the aircraft to roll to the retreating blade side.
2) Advancing Blade Mach - The advanicing tip sees an increase in its speed so that the 450 knots in a hover plus 150 knots of aircraft speed make it experience about 600 knots, almost Mach 1. Thus, transonic effects drive the advancing blades experience, and raise havoc with that blade's aerodynamic loads. Think of the problem the way the blade sees it, about 5 times a second it goes from Mach1 to stall and back again!
The way the Lynx record was set was a very intelligent application of several factors:
1) The blades were quite wide for the job, less practical for the hover (blade width robs hover performance) but just what is needed whan only a small segment ot the blade is lifting out there at 200+ knots.
2) The blade tips were carefully shaped to help transonic drag, so the advancing tip paid less of a price than a regular blade.
3) The excess engine power that was available was used in jet thrust by shaping the engine exhausts to achieve extra thrust, which relieved the rotor of that chore and helped boost the speed. As rotor thrust is "wasted" pulling the nose down and pulling the helicopter through the air, less is available to hold the aircraft up.
How do we get speed today? Three different ways:
1) Compounds like the X3 use power, props, wings and wide blades to get speed. It is no wonder that the X3 (built with the fuselage of an EC-155 at about 12,000 lbs) uses the drive train of an EC 175 and the engines of an NH-90 to do the job.
2) Tilting rotors and wings can do the cruise task, where the rotors no longer lift, and the wing does it all. The V-22 and 609 are examples of totally practical tilt rotors. Note that power still plays a part, they need about 50% more power than a pure helicopter of the same range and payload, but easily fly 100 knots faster.
3) Rigid coaxial rotors - where the retreating side's woes are ignored, and the pair of advancing blades, one on each side, do all the real lifting work. The X2 is an example, where the rotor is slowed down in high speed flight so tip mach isn't a problem, and the retreating blade has its angle of attack reduced to reduce drag and let it loaf along. The prop pushes the aircraft forward, the rotor lifts in near-autorotation, and the whole thing has reasonable efficiency and high lift/drag, albeit with the complexity of a coaxial rotor and prop. Few coaxials can go this fast, the rotors must be very rigid to permit post stall flight.
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Trevor (center) and the Helicopter Museum's Elfan Ap Rees (left) accepting the IMechE's Engineering Heritage Award on behalf of G-LYNX back in September, the recent event referenced in heli1's original post.
RIP Trevor.
I/C
RIP Trevor.
I/C
Last edited by Ian Corrigible; 1st Dec 2014 at 16:31. Reason: Alternate image source, IMechE's site having gone T/U
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Good send off for Trevor today,with a fly over by the last Flying Whirlwind 10 and chapel overflowing with family,friends and former test pilot and other colleagues.
RIP Trevor
RIP Trevor
