The Show Must Go On.
Because it's possible we'll have a long delay in this endlessly twisting and turning journey on which we're embarked, the team had a sit down this week to consider our medium term options and agree a direction.
Unfortunately we're now in a process that moves at the 'speed of dark', as one of our much loved team mates is wont to say and in an ironic and wryly amusing twist, this latest chapter began on 8th March, which was the 22nd anniversary of us lifting the wreck out of Coniston water. But it changes nothing, all we want is the same fair and equitable outcome for everyone that we've sought these past few years. The boat on display in the Bluebird Wing when not on the water with her devoted BBP team so we'll keep working towards that but what to do with our team and our workshop in the meantime?
Our first priority was to make sure all the machinery and equipment was put into a condition where it could stand for an extended period without needing too much looking at and our second was to decide what our team will be doing month in, month out because we definitely don't work at the speed of dark and there's only so much tea and Tunnocks we can consume.
One thing at a time.
Many will already know much of this but we have a lot of new followers nowadays so please pardon any repetition.
Back in 2018 we put huge effort into fine tuning the engine installation in K7 and even then we still didn't get it quite right by the time the wagon arrived to haul us to Scotland.
We would later discover that it was impossible to achieve full throttle opening, for example, and that had clearly been the case for Donald's crew in 66/67. It was down to the design of the throttle linkage and before someone says, why do you need any more throttle? The answer is that every time the pilot pressed on the loud-pedal part of the linkage was binding up and inviting itself to fail so we fixed it.
Then there was the fact that the Beryl-era throttle linkage was so mismatched to the Orpheus that any sudden, or even not so sudden, release of the throttle pedal could cause the HP fuel cock to jump its detent and shut down the engine uncommandedly. Very likely what caused the flameout on Donald's first run on Jan 4th 1967 that caused him to have to restart the engine using up the last of his compressed air so he couldn't stop to take on fuel and let the water settle and so forth...
We fixed that too.
Then the engine idle was too high, nearer 50% when 36% is about right. Yes, we fixed it this time around.
Remember we had our igniter troubles on Bute and we still haven't fixed that one but we'll get back to that in due course. We had minor fuel leaks, hyd leaks and myriad other irritating issues on Bute and let's not forget the complete absence of on-board start capability.
Another thing we had never considered before Bute was that the requirements to accelerate a boat on water are quite different to accelerating an aircraft in the sky. Put simply, accelerating on water doesn't give that extra gulp of air as speed increases because speed just doesn't increase in the same way so we had engine overheating problems so when we got back we put the engine on the test rig and reset its acceleration rate to better suit a boat.
So, with all of this in mind, we set-to with great dedication after Christmas to reinstall all the systems and make the machine as stable and well set up as we possibly could - to do a much better job than last time and evolve the installation based on what we'd learned. We also hoped this time we'd be leaving things all bolted together for a very long time because every time you unplug a plug or disconnect a pipe there's always a chance that it won't be quite the same when you put it all back together again.
We worked diligently and worked hard and so had a much better package by the time we were ready to go to Elvington except for a couple of details.
One was that damned igniter but by now we'd made a rather sinister discovery. Yes, the igniter was playing up but we discovered that it was having an illicit relationship with the boost pumps and this is the underlying problem. On one or two occasions we found boost pump fuses popped and even heard the pumps try to start once when the igniters were switched on. The exact nature of the relationship isn't clear but to be safe we'd disconnected the right hand igniter and those last few starts ahead of Elvington were done on the left hand one only. There's no perceptible difference and it laid low the electrical gremlin so that problem could wait.
We also had a persistent fuel leak on the swirl pot pump and that's as inaccessible as things get so we dealt with it by placing a square of spill matting underneath it. We're talking a few drops a day so it wasn't a big deal but despite fresh gaskets and Aerograde Hylomar it wouldn't give in.
But by far the most important matter was that by the time were ready to travel to Elvington we had assembled and set up a machine that was the best we'd ever achieved so far and probably the best it had ever been with the Orpheus installation.
Then Elvington didn't happen.
We'd burned off the fuel we put in for testing in the yard so we could move K7 mostly empty then fuel up again once on site but that left a few gallons sloshing around in the corners and pipework so as there's a chance we won't be running for a while we decided we may as well get that out too.
Now a word about fuel, because it's a frequently asked question and worthy of a mention for those new to our diary. Visitors invariably believe jet fuel to be horribly volatile and dangerous when it's really just paraffin.
Our new apprentice wanted to see just how deadly it was so we took some into the yard, sloshed it onto the concrete then tried to set fire to it. It wouldn't burn. We used a blowtorch in the end to make it flash off and it was a most unimpressive display. He was less than impressed.
But there's a little more to it as a fuel because modern kerosene has sulphur in it that likes to turn the silver components in old fuel control systems into silver sulphides and carry them off much to the detriment of the system. Older jetfuels had the sulphur removed for this reason but modern fuel systems don't use silver any more. They have carbon gizmos inside that don't care a hoot about sulphur so now we have sulphur again and need to get unused fuel out of there and replaced with something more benign if the engine is to stand for any length of time.
Our test rig doesn't use much fuel. We only do short runs on that so we've taken to using odourless kerosene. This has the sulphur removed, which is good, but it's expensive, which isn't; and as sulphur affords some lubricating qualities it's also dry and so has to be treated with a lubricity additive - something to make it a better lubricant - before we use it.
To really inhibit an engine properly we should flush through with an inhibiting fluid designed for the task and that will keep the fuel system good forever and a day but that's cripplingly expensive so we're sparing with it and use instead a two-stage inhibiting procedure that our aerospace friends assure us is perfectly good for the job, but first you have to get on the necessary plumbing.
The decision was taken that we would remove the inlet trunk, swirl pot and start bottles so we could get on the necessary pipes and also take a better look at the wiring as the part we wanted was buried in that area, then we would defuel and inhibit leaving the engine and all its connections and hard-won setup completely alone because it would be daft to have to do it all again from scratch in the event that the speed of dark process finds a way to speed itself up and we all get back on track sooner rather than later.
Unfortunately, the wiring threw up nothing obvious to our non electrical minds so that's one for Checkie in due course but as it's not healthy to leave something that will blow a 30A fuse not fully understood we pulled the fuses and left only the battery charging circuitry connected to keep the batteries in excellent condition.
The swirl pot may well have always been leaking and we just failed to spot it on Bute so that will be set up on the bench and filled with kerosene to find out what's going on there.
The defuelling is straightforward. If we're outside and running we simply burn off what's in the tank. It doesn't hold much and a handful of 5 minute runs will see to that but if we defuel in the workshop we connect a hose to the downstream end of the low pressure fuel cock, open the valve and use the boost pumps to throw the remaining juice back into a drum.
With that completed we then dropped the air bottles back on - they use the same four bolt holes as the old setup - connect up three hoses and we're good to turn the engine over to pump the inhibitor into the engine's veins.
Remember all the development work we did on the start turbine to match the efficiency of the old 1966 version? Another advantage of it's now staggering efficiency is that we can crank the engine using a tiny amount of air. Whereas before we needed 700psi in a pair of 50 litre cylinders to complete the process we can now use 300psi in a pair of 15 litre cylinders. It's a transformational improvement.
The air storage is a beautiful creation and a direct drop-in replacement for the old system and, rather excitingly, because we now fully understand the start turbine on the engine and how to wring the best out of it and how to use that to start the engine, there is just a very outside chance that we could get the old system to a point where it will once again start an Orph'. Now what an achievement that would be. But that's another one for the future.
The basics of inhibiting an engine is that you open the HP fuel cock then keep the motor turning for a minute using two or three short stabs on the starter. By doing that there's no violent acceleration of the engine and a steady run can be achieved that pulls the fluid through the main fuel pump, into the fuel control unit and then out to the burners. We temporarily reattached the swirl pot and used a hose to bypass the auxiliary fuel tank down in the hull simply so we could work with a smaller volume of fluid.
Mich put the swirl pot back in place and made the connections. It wasn't bolted in, just perched where it lives and secured with a clamp.
Then Gordon measured out a half a gallon of fluid and poured it into the swirl pot. At this stage we were using odourless kerosene with a lubricity additive to give the fuel system a good flush through. The Aeroshell inhibiting fluid will go in last. There's a boost pump in the swirl pot but we didn't run it. There's no need because it's designed such that if it fails fuel can still be drawn past it to keep your aeroplane aloft.
After a moment to let that trickle down and belch any bubbles back out it was a case of crank over the motor to flush out the pipes. It doesn't go fast enough to build the pressures necessary to atomise the fuel so instead of the characteristic mist of unburned fuel we get with a failed start all you get in this instance is what looks like raindrops in the jetpipe but the message is clear as can be. The juice is being pumped through to where we want it.
What happens is that the swirl pot is sucked empty and its contents dribbled into the combustion chamber, that's that big cylindrical can in the middle of the engine, having washed out the old fuel but then we have to get it out of there. You can hear hat we call, 'rain in the jetpipe' as it drips inside and pools in the bottom.
In normal use there would only be a small amount of waste fuel in there after every shutdown so there's a sprung valve in the 6 o'clock position that opens when there's no pressure inside so fuel can simply fall out of the bottom of the aircraft onto the ground. That's messy in a boat so the solution they devised in 66 was to have that fuel drain into a small tank low down in the hull that is briefly pressurised as the engine starts before the sprung valve closes and that pressure threw the contents of the tank overboard into the lake.
We added an extra tank on the side of the engine where we could get at it and had the pressure from the spooling up engine push the fuel to there instead but when inhibiting, firstly there's a lot more waste fuel to deal with than when in normal running condition and, secondly, the engine never spins fast enough to blow it up to to the tank so it has to be drawn up there using a vacuum cleaner.
The pipe from the bottom of the engine is clear so by sucking on the top of the tank and keeping an eye on the pipe it's possible to see when the combustion can and the small catch tank below is empty.
Then it's a case of manually checking and emptying the upper tank.
Notice the paper element filter on a spigot inside the lid of the tank. That's so there's no chance of atomised fuel making it out through the breather in the top of the cap in normal operation. It was thoroughly tested on Bute and proved to be one of those things that worked brilliantly straight out of the box. You don't get too many of those.
Gordon became chief in charge of emptying the tank by the simple expedient of siphoning it into a jug.
Once we'd put a gallon of odourless kerosene through we rounded off the procedure with a good dose of Aeroshell #1. That's the real deal, proper stuff as recommended by aerospace and as they were kind enough to train and look after us we repay that generosity by doing things by the book they taught us from.
So that's the engine inhibited but otherwise still stable and set up, the swirl pot leak is yet to solve and Checkie is going to get to the bottom of that electrical thing if it's the last thing he ever does! In the meantime we put the lids back on to get them up and off the floor because we don't want all our lovely paintwork in the way of possibly getting scratched. It looks easy here but putting the tail on without it falling over is quite juggling act but we've done it so many times it's become second nature.
The engine cover went back on too. The covers are just pinned down for the moment. Setting them up so all the quarter turn fasteners work is a task we only ever completed once and it was really tricky so that' another one for another day.
Next week we need to get the canvas transport cover over the top and move the boat over to the side of the workshop a little because the answer to our second big question just fell into our laps - what would our Bluebird Project family turn its skills to in the interim?
Almost as soon as we discovered we actually had an interim at all an old ally came to us asking if we could lend a hand. It seems we're in demand so we have another project coming to visit for a few weeks and I think you're going to like it. Watch this space.