key.aero looks at the B-17 Preservation Society's trying time over the last two years.
Gary Parsons - 17-Jul-2009
Duxford’s Spring Air Show may have had the theme of ‘Best of British’, sporting some unusual and interesting airliners from the annals of British aviation, but it was an American aeroplane that most spectators were glad to see. People often say “Best of British” when offering good luck – luck is something in short supply with the B-17 Preservation Trust in recent times, but it seemed that they had turned a corner as the day saw the very welcome return of an old favourite to the skies above the Imperial War Museum, that of B-17G Flying Fortress G-BEDF, or ‘Sally B’ as it is affectionately known. After a year of being grounded due to a series of mechanical disasters, many feared that it may never fly again. But ‘Sally B’s story has often been one of triumph over adversity, and so it has proved once again. Pete Brown, long-time Chief Engineer, takes up the story:
‘Sally B’ is serviceable again after some 500 days - it was October 2007 when we lost the first engine. At the end of the season our number one engine had high oil temperatures and low pressure, not a good combination. We had all winter to replace it, so not a problem - the engine had been on for twenty-three years, had done about eight hundred hours and was last overhauled forty-five years ago! It didn't owe us anything. We had a spare engine, which had been in storage for nine years, and fitted it over the winter. We did all the necessary final inspections, and although the oil pressure appeared slightly low by a couple of pounds, it didn't seem to be a problem. But when we did the high-power tests on the airfield, it failed; it didn’t even make the air. We’d already received another engine to replace the broken one, so we didn’t think it was a big problem.
Pete Brown, Chief Engineer for the B-17 Preservation Trust, casts an eye as his engines start. Key - Gary Parsons“The fresh overhauled engine from the States was fitted in five working days. Again, we did the low-power tests and everything seemed okay. On the first test flight, just across the back of the airfield, this engine also failed - again, falling oil pressure. The pilot shut it down very quickly to try and save it, but it was too late. It was mid-May, just before the season started, so that was a bit of a disaster.
“So there we were with three failed engines - we've traced the first fresh engine failure to a bolt that was stuck in the oil feed pipe and restricting flow - we've no idea how it got there, but must have been missed at its overhaul.” Unfortunately for the team, as the engine's overhaul was over a decade ago the chances of any compensation are slim, the warranty long since ceased. This isn't the case with the second failure, as this had just been received back from strip down and overhaul in the USA. Damage was severe, as it needed a new crankshaft. Shipping costs back to the USA still have to be borne, something that the hard-pressed charity cannot easily afford.
Pete continued: “The first one that failed, we’d got that down to Deltair Airmotive at Portsmouth who did our engine when we had the same problems in Guernsey about ten years ago. They eventually provided us with an engine at the beginning of this year, and we fitted that and ran it for an hour, then took all the filters out - they were still clean, because it hadn’t been run on a test bed. That can be a problem; you get an engine off a test bed and it’s done four hours, so it’s had time to get rid of all the little bits of metal, the manufacturing swarf. After an hour and a half in the air and we took it out again to flush all the systems, so at the moment we are up and running and we’ve got ourselves an aeroplane at long last!”
A sight not seen often enough in 2009. Key - Gary ParsonsAfter two ‘new’ engine failures, Pete was immensely frustrated. “Oh, it drives you mad - you begin to doubt your own engineering ability. It’s never happened to me in all these years I’ve been changing these sorts of engines, and bigger engines than these.”
Although the latest engine was performing well, the team are nervous with four engines to care for as they don’t yet have a spare if further dramas occur. “That’s the other problem - we’ve really got to source an engine quite quickly. You can’t wander too far from home because the expense of losing an engine away from base, as we know from Guernsey is horrendous, and so we really need to sort of watch our movements a bit until we get another spare. Of the other three engines, number 2 is the Deltair overhaul from Guernsey - that’s got about 300 hours; number 3 is the one that came over here on the Hendon B-17, so that’s got about 600 hours, and number 4 is a replacement for one we gave to one of the other B-17s during the Memphis Belle filming in 1989, so that’s got about 700 hours, a little over half life – 1,200 hours is about the maximum before overhaul.” At a rate of 20 hours a year, there’s potentially a lot of life left before the team needs to worry, but of course each year is new territory with engines designed some 70 years ago.
Pete is grateful for the financial support from Norfolk man Bertie Ashby, without whom ‘Sally B’ may have been facing a second season on the ground. “It was a real godsend,” said Pete. “It allowed us to buy the engine without too much worry.”
'Sally B' at Shoreham's airshow in August - the smoke is fake this time! Key - Gary ParsonsBertie, a pensioner from Wymondham, got his interest in military aircraft as a child as he watched US Army Air Force bombers taking off and landing at nearby airfields during the Second World War. Hearing of Sally B’s plight, Bertie donated £360,000 to the B-17 Charitable Trust following the sale of some land. “It's no exaggeration to say Bertie Ashby is our saviour,” said Elly Sallingboe, Operator & Chairman of Trustees. “Without his donation we would be finished. The series of engine problems we faced last year, coming after the 2007 season was virtually washed out by the weather, almost drained our coffers.”
Bertie has been made an honorary member of the Sally B team and appears on the plane's roll of honour following his outstanding gesture. There was no prouder man at Duxford on Sunday May 17.
Sadly for the team, the joy at being airborne again was short-lived – a tell-tale whisper of black smoke from the new engine had many wondering if it would last. Strip-downs over the next few weeks confirmed the worst; it’s thought that the crankshaft bearing may have failed. Just how much bad luck is the team having? Elly Sallingboe said “How this happened, no-one can explain. We are at this moment in total disbelief, totally perplexed and utterly devastated. Where do we go from here? At this moment we are scouring the world's warbird fraternity in the search of a reliable replacement engine - a full investigation into all aspects of the recent engine failures is being done and no stone will be left unturned.
'Sally B' closes the season at Duxford's Autumn Airshow. Key - Gary Parsons"Believe me no one is more devastated about this than I am. Our ‘Sally B’ will be flying again as soon as humanly possible.” This time US-based B-17 operator Don Brooks came to the rescue with a spare engine, one with some flying time so it was tried and tested. By mid-August the engine was fitted, and it was with some relief that 'Sally B' made its second comeback appearance of 2009, this time at Rougham's Heart FM airshow - a fitting venue, as it was home to the USAAF's 94th Bomb Group and its B-17Gs during the Second World War.
'Sally B' was the last airshow act of 2009 as it closed out Duxford's Autumn Airshow on October 11 - let's hope that it opens the 2010 season at Duxford next May 16. Best of British to them.
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