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Post by Dave Homewood on Jun 18, 2008 19:13:00 GMT 12
Allan, that's the film that plays inside the preserved Argosy, isn't it? An excellent film. Paul is a great bloke too.
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Post by Allan Udy on Jun 19, 2008 9:49:00 GMT 12
Dave,
Quite correct, the Argosy video that's on YouTube, is the video that is played if you do the 'virtual flight' at the Argosy aircraft cafe here in Blenheim. Some of the footage in this video is specific to this use only, and doesn't actually appear on the DVD at all.
Cheers Allan
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Post by Gavin Conroy on Jun 19, 2008 20:31:40 GMT 12
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Post by Radialicious on Jun 19, 2008 23:31:50 GMT 12
Hi again, I'm back from an interesting 3 days on the airfield trying to get to the bottom of the problem with the stbd donk. It has suffered slightly from the oil pressure problem on Sunday but is now on the way back to full health. The last two days were spent pouring copious amounts of thinned out oil in and around the cylinders in an attempt to free her up to where she was a few days ago. In many ways now, she feels like she did when I first pulled the cowls back in March. I pulled an exhaust pipe from one of the front cylinders to have a look at the condition of the sleeve. It was heartening to see a healthy film of oil on the sleeve and the fact that there is enough clearance between it and the cylinder for it to absorb penetrating oil. By stumps last night, Marty and I were able to pull her through a few blades. With that in mind I did quite a bit of research of the manuals last night to try to get to the bottom of it today. I was keen as a keen thing this morning when I woke up and was looking forward to getting amongst it as soon as I could. But waitaminnut, minus four degree frost............ It was a day for the pure enthusiast - there were even icicles hanging off her!
Today's mission was to remove and inspect the oil pump. The manual said something along the lines of, "It is considered a rare event to remove the oil pump inside the service life of the engine". Knowing the english designer as well as I do I read between the lines to read, "Oops, we left that one a bit tight to get on, not much room for a spanner wot? in our well lit factory, outside of the cowls, not on a stepladder, not in a 4 degree frost, um, a wee bit snug gentlemen? That's OK, we'll make mention in the manuals that it should never need to be removed. That should keep everyone happy. Oh well, chin chin, bring your slide rules to the bar and we'll have a jolly good laugh at the poor blighter that ever wants to remove a Bristol Hercules oil pump. Hooray!".
And so it was. 6 No.2 BA nuts and two unfeasibly large oil hoses as flexible as a 6 inch diameter glass rod - six inches long. The access to the nuts for the first time in this project almost made me angry. However, it was the frost that did that as when I felt for the nuts in the darkness of the cave, I was lucky to even feel my dubfweruoa - whoops I meant fingertips (flashback). Just so I don't make myslef angry again, I'll fast forward to the moment the pump slid off its mounting. PLOP. WTF was that I thought? In the bottom of the cowl was a chunk of something that looked and felt like a skody old piece of soap. Like what you'd find against the grate before the drain of the showers of a busy camping ground in the middle of a kiwi summer. "Hmm that's odd", I thought as I slid the pump away from its mounting. There was a small amount of relief that I had found the problem - mixed with the horror of finding a magnesium pump body that had dissolved from the inside out!
It seems that the small amount of oil in the tank had reacted over 20 years with the pump body and turned it into soap. There was little wonder that we lost oil pressure and amazement that the engine ran for 2 minutes with little or no oil pressure. As the oil pressure transmitter recieves oil from the same cavity as the hot oil prime and the delivery gears, it isn't surprising that nothing seemed amiss as we looked at a healthy 80psi.
I got onto a few sources of Bristol parts locally and have secured a replacement pump which I hope to fit this weekend. All cylinders and exhausts will receive a sluicing of this oil this weekend. After I fit the new pump I intend to 'oil prime' the internals with kerosene to get as much lubrication and penetration back into all the close tolerance parts of the engine. Hopefully this will act as a really aggressive detergent to flush out anything else inside the oil system. Once done, the sump will get a real good huckout before draining and doing the same with warm oil. As much as I are't looking forward to pulling the port pump, it is my duty to check the same isn't happening on the other side. I have some photos of my discovery which I'll post shortly. All this seems like a setback and some people would look at it as such. However, I'm learning lots and am in no rush to move to the next phase. Hopefully next week, I can run the stbd donk again and all going well get some kinda stereo action goin' on.....
Fingers crossed!
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Post by Dave Homewood on Jun 21, 2008 0:22:56 GMT 12
Hmm. Freezing cold temperatures and an engine that won't run to its potential. It sounds like you need a bottle of MotorUp Good luck with the new pump.
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Post by Radialicious on Jun 23, 2008 16:36:04 GMT 12
I saw some Motor Up at SuperCheap today and had a laugh. In this case however, one bottle would probably treat one cylinder! Here are a couple of pics of oil pumps - old and new
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Post by Bruce on Jun 23, 2008 16:55:21 GMT 12
That'll buff right out.... I'm impressed that the engine managed to run at all with that sort of crud.
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Post by Dave Homewood on Jun 24, 2008 0:30:49 GMT 12
That is quite exyraordinary. Work keeping as a museum exhibit I reckon.
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Post by skyhawkdon on Jun 24, 2008 20:05:05 GMT 12
Yes that is quite something Al. It would be interesting to know what caused that. It's almost like battery acid has eaten away the metal. Good that you have found a replacement pump and that there doesn't appear to be any major damage done. It says a lot about how effective your preoiling was I'd say.
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Post by Gavin Conroy on Jun 25, 2008 19:03:16 GMT 12
Good job getting the new pump Al. I saw the old one on Friday night during beer time and it looked pretty bad and like Don has said, your hot oil prime etc was the right way to go.
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Post by Dave Homewood on Jun 25, 2008 20:47:27 GMT 12
The manual said something along the lines of, "It is considered a rare event to remove the oil pump inside the service life of the engine". I guess they got it right then, but they never envisioned you'd come along and give the engine an afterlife.
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Post by lumpy on Jun 25, 2008 20:56:15 GMT 12
As Don says , looks like acidic moisture damage . If moisture finds its way in , either directly ( like some sort of open breather when its raining or being washed ) or indirectly ( condensation WILL form in an engine on a cool night , after a warm day , same as it will in half empty fuel tanks ) .The moisture will then fall through the oil ( because its heavier ) , and pick up any contaminants that may be present on the way .If the oil wasnt brand new , then sulphuric acid would likely be present in the oil ( as in acid rain ) , and since the scavenge oil pump , or its pickup is usually at the bottom of the system , it cops the hiding . I dont actually know where the dodgy pump is located , so Im really only guessing in this case , but its sure not natural decay . Actually Im not even sure if its a scavenge pump ?
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Post by Radialicious on Jun 26, 2008 20:48:52 GMT 12
Home of a Hercules oil pump. The pump lives just below the (black) magneto on the left hand side of the accessory casing. It has a rather large inlet hose, three scavenge system hoses, external pressure feed to the sump, oil pressure outlet and oil prime inlet. As I mentioned, there was an unfeasible lack of access to the six No. 2 BA nuts and washers that secure it. The guys were dead right about the source of the corrosion. Old oil full of acids, sulphides and a certain amount of moisture made a 20 year meal of a magnesium pump body. I now have the replacement pump fitted and have done quite a thorough huck-out of all the external hoses and the sump itself. She is now scunge free. Yesterday I hooked the hot oil priming rig up to the pump in an effort to pump oil under pressure into the oil system. First up, I chose a few gallons of diesel. The idea behind this was to perhaps flush the galleries clean and hopefully set up an oil mist in the crankcase that might penetrate in and around the sleeves. The stbd engine is still very stiff to turn but is slowly responding to some sympathetic TLC. I still feel a bit guilty about bringing her back to life without oil pressure! In saying that, such a curveball was impossible to predict. The oil pressure gauge in the cockpit didn't register during the prime with diesel, I guess because of its low viscosity and it was soon recovered from the sump drain. Straight oil brought up 90 psi on the gauge so I made a compromise mix that I hope will penetrate and lubricate. What i want to achieve is a thorough splash lubing of the internals that will sift into the base of the sleeves and amongst the cylinders. The prop is quite hard to turn by hand but I need to remember that it is turning through a .444 to 1 reduction gearbox. Any stiffness will be doubled even though I am pulling through a 7 foot blade. The pistons to sleeve interfaces are well oiled but it is a matter of getting fresh oil between the sleeves and the cylinders. I'm considering using the starter to assist me. Very little splash lubrication occurs via grunting and huffing the engine through man-draulically. Direct cranking and oil priming might achieve the splash lube that I aren't yet getting. I'll do some more research on that one. Its a big call. The starter has a clutch that senses excessive cranking torque that is normally a hydraulic lock. Like I say, I'll give it some thought! Today wasn't a good day to be on a stepladder as we were hammered by a 35-40 knot westerly.
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Post by lumpy on Jun 27, 2008 23:18:55 GMT 12
Drives you to drink ( like I need an excuse ) when a component is held on by 6 bolts , but you can only reach 5 ! I know little of your situation with this engine , but if you can prime the oil system , then cranking on the starter should not hurt ( and if it does , then the damage was already done ) . I vote go for it
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Post by avro683 on Jul 1, 2008 8:52:06 GMT 12
No video of the stbd engine run.....?
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Post by Radialicious on Jul 1, 2008 10:28:52 GMT 12
There were a number of video cameras there on the day. I'll try and track some footage down. The STBD engine is coming back to health slowly and is responding well to a good oiling from anywhere I can poke oil into. As it is the sleeves that are in the biggest need of oil, I have started oiling her from the exhausts. A length of garden hose can be pushed and twisted past all but the sharpest bends. Into this I slide a smaller, more flexible hose further into the exhausts to hopefully apply oil directly to the face of the sleeve in the exhaust port. The prop can be pulled through now albeit with some difficulty at times. There is a definite sweet spot where it almost feels normal. I'd love to be able to attack the sleeves through the induction system as there are three inlet ports on each cylinder. This would put more oil onto the sleeves sooner. However, as I say, it is responding well and I'll soon be able to use the starter and the pressure priming rig to get her back into shape.
We'll make sure of some video for that one. I'm keen to record exactly what needs to be done in the cockpit to make her bark. It is quite an adventure being up there and with six levers and switches that all need attention, it is also a good exercise in hand/eye/ear coordination!
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Post by Radialicious on Jul 2, 2008 22:51:36 GMT 12
Had another morning on the stepladder this morning with my trusty goop-gun. She's still making steady progress in getting freed up. I did some sums just now as a rough estimate of the contact surface area of the sleeves inside and out. My sums add up to (very roughly) 3 square metres of close tolerance metal to metal contact that need lubricating again. I now feel like the Bristol equivalent of a proctologist - attacking her from the exhaust(s) with my garden hose and pressure gun. My dirty work clothes are dirty beyond dirty and as Vyvyan from 'The Young Ones' once loudly proclaimed about his underpants, "it is only the stubborn understains holding them together..."
We had a committee meeting as Friends of the Bristol the other night. One of the members, on hearing of my battle 'up the back end', asked me if I was still enjoying myself. "Too right!!", was the reply. My only wish was that I had started this project sooner before winter set in. I am also on a race against the clock with regard to a move to CHCH to fly for Mt Cook Airline. I want the old girl all squared away so that I can leave her in good health. The Line Ops Manager of Mt Cook suggested that she would be the ideal means of moving all my stuff to CHCH. I'm sure that she would almost know the route off by heart and would leap at the chance. At our meeting I outlined my goals for her in the short term. It was agreed that we would keep her runnable until Classic Fighters '09 and inhibit her shortly afterwards. In the meantime, periodic running days would be publicly advertised and carried out to keep her happy and through donations, pay for fuel and oil, and put a bit back into the bank. I proposed that if my plan to taxi her came to fruitition, a raffle be held on the days of the airshow to allow the winner to sit in the cockpit during her ground display. Whether it be the front seat or jumpseat is yet to be determined. It would be a hell of a buzz for Joe Public and a good means of generating some cash for her preservation. I'm curious to hear what everyone would be happy to pay for such a prize. I think if it were 10 bucks, that would be 10 bucks well spent!
Tommorow is a good day for me as I don't start work until 5.00pm and fingers crossed there will be no frost.
Frostologist out.
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Post by corsair67 on Jul 3, 2008 12:04:02 GMT 12
Al, I personally think $10 would be well spent on the opportunity to sit in a Bristol Freighter during start-up and taxi.
Keep up the great work, and I hope all goes well with the move to Christchurch too.
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Post by Radialicious on Jul 3, 2008 22:15:04 GMT 12
Thanks Craig, it will be weird moving back to CHCH after 19 years away. I suspect a quite literal homecoming on arrival as Mum says my old room is available... That's cool though as it will make the move to a new company and new aircraft easier without having to look for a flat first up. Today was steady at Omaka. Me and my goop gun spent another few hours on the ladder gooping, turning, gooping.... However I decided I needed a less hit and miss means of negotiating the branch that joins the front and rear cylinder banks in each exhaust pipe. My good mate Wayne Tantrum of Antique Aero Engineering 'has' a (was) rather lovely LCD screen boroscope with a metre long probe. I decided it would be perfect to assist me in finding the branch in the exhaust and selectively oil either the front or the rear cylinders. Wayne happily lent me his boroscope and it worked a treat. I felt I had gone from carpet bombing the entire exhaust ala B-17 to smart bombing the chimney of just one house. It was so surgical and accurate that I thought all my problems would soon be over. A few more of these I thought and we'll be back in action before you can say slip-fall-crash.... I never heard the part where the boroscope actually fell, but I heard the slip and crash quite clearly. From the upper suburbs of Herculesville to the concrete pad below was more than enough to smash Waynes beautiful boroscope into more pieces than I wanted to count. He took it well. He also quickly found the business card of his agent in Nelson who will happily supply a new one via my credit card. I thought it appropriate that a quote of $666 would follow..... Shortly after that, I put CLT to bed for another night and sulked off to work to pay for my day on my ladder
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Post by Dave Homewood on Jul 3, 2008 22:58:36 GMT 12
That's a bad setback Al, sorry to hear that mate. At least it is replaceable, and it wasn't you that fell off the aircraft.
When you said in your last post that she will be inhibited after the airshow, is that deemed to be permanent? Or will it be done so she can be pulled out of her sleep again for future run days?
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