I'd be very interested to see updates as to how you are getting along with XL319, posted here.....
Since we first ever visited XL319 many moons ago to gather some valves and plug connectors for the K7
build we wondered whether we might light one of her engines. This was way before we'd ever lit one of our own but the idea was there.
So - seeing as K7
is now mothballed in bits until the dark nights come around again we decided to take a serious look at whether it could be done.
The first problem is that XL 319 last felt the heat of combustion 36 years ago and ever since her engines have been slowly congealing into solid, immovable lumps. We decided to go take a look with the blessing of the museum. Of the four engines the two inboard ones are the worst. There's a short, removable trunk between airframe and engine inlet that has worked against those two by letting rainwater get all the way to the compressor whereas with the outboard engines the trunks are missing so the water simply fell out through the bottom and left the engines relatively dry inside.
This halved our options to engines 1 and 4.
No.1 points directly at a mobile phone mast - not that the jet wash at idle would hurt it especially - but No.4 would miss it completely so we chose that one.
Next problem was to see if the engine would ever be capable of starting again and that question still hangs in the balance. The Oly is a twin-spool engine. In a nutshell, it's an engine inside an engine.
The LP compressor drives the LP turbine while the HP compressor drives the HP turbine. They run at different speeds so they each have their own drives shaft with the HP shaft being hollow with the LP shaft running through the middle of it.
https://www.google.com/search?q=twin+sp ... lIx8iwyqRM
Where this presents a problem is that the HP spool runs all the pumps and accessories and we all know how much fun those piston pumps are when they seize up and the HP spool is buried deep inside of everything where you can't even see it let alone do anything to get it turning. We've fought the tiny B-size Lucas pumps on the Orph' but those on the Oly are monsters by comparison. To aid with things like bleeding the system the Oly comes with a pair of handy turning points let into the gearbox onto which you pop a socket, having removed the blank, and simply wind the relevant spool over with a ratchet. It has a simple dog-clutch that you engage by pushing the drive against a spring and off you go. Except that our HP spool just didn't want to budge.
Long story short - we got an eighth of a turn on the spool using a scaffold pole before the drive failed and took the tips off the dog-clutch. We swapped out the drive from another engine but the half of the clutch inside the gearbox was damaged too and it wouldn't re-engage sufficiently to get any more.
But the fact that it moved at all was encouraging. It obviously isn't seized solid so we had to look at another way of getting some drive into the gearbox.
First thought was to blast some air through the starter but that would be pretty violent and doubtless shock something. Then we thought maybe we could get the starter off in-situ and get a spline drive into where it came from to put a big pull on the gearbox and maybe get things moving that way but, as was pointed out today, not a single millimetre of space that could otherwise be given over to bombs or fuel is wasted on letting you get a spanner onto something so getting the starter off is a no-go.
We seemed to be running out of options at this point until a learned Vulcan engineer suggested that we get at the gearbox via the hydraulic pump drive. The Vulcan has three hyd pumps and guess which lump doesn't have one. No. 4. It took us five minutes to whip off the blanking cover and have a peer into the drive.
It's a female spline but the encouraging sign is that it's working with some pretty chunky bevel gears that we'd need some colossal force to break. Of course we don't know at this stage the extent to which the the gear ratios will work with us or against us but it's obvious that by going in via the hyd pump drive that we can get massively more torque into the HP spool gearbox than we could ever manage via the turning point.
So that's where we've got to. We'll go back next week and measure up the splines, have a shaft machined up then swing off it with a scaffold pole. The advantage there too is that the turning point only lets you turn the spool in one direction whereas if we can get a good pull on the hyd pump drive we can work things back and forth and that's always a better deal.
Assuming we can crack the HP spool loose we'll then have to blast the HP pumps full of something oily and penetrating via the inhibiting points, get the air start working, power up the HEIUs to make sparks, sort some lube oil, fuel, instruments and controls and then, just perhaps...