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Post by Radialicious on Mar 27, 2008 22:43:47 GMT 12
Hey all, I'm writing this to give a bit of publicity to a project of mine that has just kicked off at Omaka and involves the Marlborough Aero Club's Bristol Freighter ZK-CPT. I'm a propliner fanatic from way back and a member of MAC since 1990. Ever since I have been a member, ZK-CPT has sat, silent, on guard in front of the MAC clubrooms. Her preservation has been the focus of the Friends of the Bristol. FOTB formed shortly after she landed at Omaka in 1986 and have maintained her in a state of static display ever since.
As a boy, I was able to sit in the cockpit of ZK-CLT when she was owned by the RNZAF museum and run up prior to her trip to Canada. Ever since I have had a bit of a soft spot for for the B-170. When I joined the MAC, ZK-CPT was still on the airfield and had recently been run. She now lives outside the aeroclub bar and has become a silent but not forgotten relic of NZ's history.
I'm keen to reverse her 'silent' nature and have started a project to breathe life back into her engines. Both engines were run and inhibited back in the 90's and a certain amount of preservation was carried out on the airframe. Recently I noticed a propeller had been turned through 30 or 40 degrees. Obviously this does the inhibiting no good at all. In saying that, inhibiting doesn't last forever either. I decided that it is about time that we did something to re-preserve these engines.
I am looking two courses of action. Both involve running the engines to get oil in amongst the guts. After that, one plan is to re-inhibit the engines, immobilise them and leave them alone. The other is to run them periodically and keep them in a condition where we only need a battery cart and a source of fuel and oil. Both have pros and cons. Personally I would like to see these engines run more often than not for the following reasons, 1, there are very few B-170's anywhere in the world in running condition 2, a living machine would attract more visitors, attention, donations and support than one sitting mute. 3, group visits to Omaka and the Aviation Heritage Centre could, through donations, provide towards the cost of fuel and income than we presently recieve 4, twin, twin row, sleeve valve radials sound bloody good at the best of times and there are a lot of people who would love so see and hear them again.
To support this, I took the cowls off the port engine today to see whether I was barking up the wrong tree. I was pleasantly surprised to see that, externally, everything looks really good. The internals of the magnetos and carbs is anyones guess but it seems like there is only one way to find out......
I would love to see our Bristol Freighter taxi up and down the crowd line at Classic Fighters 2009 and perform a run-up in front of the crowd during the lunch break. It's a long way off but I reckon it can be done.
What are your thoughts?
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Post by skyhawkdon on Mar 28, 2008 6:43:28 GMT 12
That is a great idea. Have you thought about approaching Safe Air for some support? Even if it was just to lend you a battery cart, some fuel and oil! They might also be able to repair the damaged wing tip? As an AC on Basic Engineering at Woodbourne in 1984 we used to watch and listen to them starting and running up every day from 4TTS. On cold winter mornings they really struggled to turn the engines over and get them going. They were quite a sight and sound.
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Post by corsair67 on Mar 28, 2008 10:07:04 GMT 12
Al, I know what you mean when you talk about having a soft spot for the B-170, as growing up in Christchurch I used to see them coming into Harewood all the time - battling the nor'-westerly during Summer. I think you are right that people like to see a live aircraft rather than one just parked up an rotting away, plus to hear those engines run again would be fantastic! Roll on Classic Fighters 2009!
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Post by Bruce on Mar 28, 2008 10:44:01 GMT 12
Go for it Al, Should be great to hear some big round engines chugging away. Hopefully the all important sleeve - barrel interfaces have held up O.K, otherwise it will be a huge job. Conventional valve trains don't have the same issues, but hopefully plenty of inhibitor got into everything and everythings still good. Should be a great smokey time!
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Post by stingray on Mar 28, 2008 14:56:50 GMT 12
Where can i donate-seriously?
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Post by p40fanatic on Mar 28, 2008 15:40:16 GMT 12
Al, sounds like a fantastic plan! Please keep us posted! Superb!
I vote for the running/taxiable plan, as quite rightly Omaka should play host to a running Freighter.
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Post by lumpy on Mar 28, 2008 20:01:01 GMT 12
Agreed , it would be a great shame if the engines were no longer able to be run , simply because nobody actually did . Would be a good project to run , than re inhibit the engines once every two years or so ( around easter time ) :-)
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Post by amitch on Mar 29, 2008 8:17:00 GMT 12
Sounds like a great idea and something the AHC should be involved in. After all, It's certainly a part of our aviation heritage.
As for sponsorship, Goldpine seems very keen to help with aviation related projects!
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Post by Gavin Conroy on Mar 29, 2008 9:39:19 GMT 12
Yip, this is a great idea. Al and I have spent some time discussing this project and I hope it all goes well.
As for sponsorship, thank you for the plug Alex but Goldpine wont be involved this time round although we sponsor many projects around the district not only aviation but its good to be able to help where possible. Free time and effort will most likely play the most part and I am sure Al will accept any offers with that.
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Post by FlyingKiwi on Mar 29, 2008 20:24:47 GMT 12
Sounds like a great idea to me! Here's a photo of the aircraft in question for those who haven't been to Omaka: In rather better condition than the Ardmore Freighter! Leo P.
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Post by Richard Wesley on Mar 29, 2008 21:30:00 GMT 12
Sounds like a great project. Note that MoTaT has four Bristol Hercules engines from the Hastings that was broken up at Ohakea, they might be useful for spare parts if needed. Perhaps even ask Motat for a loan of one for display if you don't already have a spare.
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Post by kiwi on Mar 29, 2008 21:56:05 GMT 12
There is another Freighter in a park in Nelson .
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Post by Bruce on Mar 30, 2008 10:54:19 GMT 12
Dwen Airmotive at Ardmore has most of the former RNZAF Spares stock. There were a couple of completeB170 QEC engine assemblies tucked away in various Ardmore Hangars in the past as well. Certainly bits for Hercules radials aren't too hard to come by in NZ - one of the advantages to being the last place the Bristols served in any great numbers. When i was at Gulf aeronautics looking after the sea fury, we found Dwens were very useful for obtaining spares for the centaurus, as there were quite a number of smaller fittings etc that were common between the Hercules and its bigger brother.
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Post by stingray on Mar 30, 2008 12:03:36 GMT 12
Dwen still have the Hercules engines sitting outside covered by tarps. The entire aircaft is there, just in a sad state.
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Post by Dave Homewood on Mar 30, 2008 13:45:17 GMT 12
Al, this sounds like a very worthwhile project. Well done for taking the initiative.
I for one have never seen nor heard a Bristol Freighter running in the flesh, only in old films, so I'd love to have that opportunity. I'm sure if it was run something like one day per month on a weekend, it would become popular with visitors to the AHC, etc. I rememebr how impressive the experience was of seeing the Lancaster with all four Merlins running at Motat as a kid, and though this won't be quite in that league it's still going to be one of those experiences that kids and adults alike won't forget in a hurry. It will likely inspire a new generation to come to love radial engines.
If it were made taxiable perhaps there's even potential for rides like the Lancaster does at East Kirkby. It's a possibility.
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Post by ErrolC on Mar 31, 2008 21:47:32 GMT 12
I for one have never seen nor heard a Bristol Freighter running in the flesh, only in old films, so I'd love to have that opportunity. The 'worst' part of living at the end of Whenuapai's landing lights was when the BF's practised night landings - engine-out night landings. A beat-up from a Skyhawk was over in a flash, but those birds took ages to trundle over on one over-worked engine!
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Post by Dave Homewood on Mar 31, 2008 22:01:26 GMT 12
I can see that would be annoying. Like the Iroquois's that used to hover over our barracks at Hobby at 3am!
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Post by Radialicious on Apr 1, 2008 19:30:39 GMT 12
Hello again, just a bit of an update. Thanks for the encouraging responses! Stingray, when we work out a few more of the how's and why's etc, I'll let you know. Thank you. Alex, the AHC are more than interested in this project and have so far been very helpful. They have a complete library of B-170 manuals and I have spent a few hours upstairs researching this machine and finding out how she ticks. It is a surprisingly complex and well thought out aircraft. After many years working on RR Viper turbojets and Lucas gas turbine fuel systems, I have an understanding of how the British engineering mind works..... Enough said about that. A day off last week was spent with all the cowls off the port engine surveying the landscape. The Bristol has a very clever and/or English method of achieving cooling without the need for cowl flaps. As Bruce will know, there is very little space left over inside the cowls on a Bristol sleeve valve engine. An observer on the outside sees an external cowling that gives the powerplant its shape. Underneath that is another cowling that provides guidance and sealing to the air that cools the cylinder heads. This air exits the cowl from a separate ducting system from that that cools the cylinder barrels. When you lift the cowls, all you can see is the ignition leads to each cylinder - nothing else. This internal cowl is in two halves secured with turnbarrels. They quickly undo and can be slid away from the engine itself. I wish I had a camera for the moment when the outer cowls were lifted. They hadn't been open since 1990 and even through the best efforts of a myriad of bird proofing, were literally an apartment block for several generations of feathered vandals. Initially I thought that I was gonna have to play the nasty landlord and evict a squillion bludgers who had called this place home for nearly 20 years. With the internal cowls removed the engine was still not remotely visible! I will make a point of photographing the starboard engine from start to finish to record what was effectively a fourteen cylinder hay bale. From the top of my stepladder, I quickly removed great handfuls of all sorts of building materials. The amount was staggering. The pile underneath the engine quickly grew to the point where I was wondering if a ladder was going to be necessary towards the end of the eviction. In saying that, there was no-one home and only one dead bird remaining (with no head?!?!). I had concerns as to what damage all this material might have done to the delicate cooling fins on the cylinders in terms of corrosion. I have seen Lycoming fins rusted away from whale watching machine and some coastal topdressers. However it soon struck me that there is NOTHING on a Bristol Hercules that is delicate. It took only a few hours to demolish what took 20 years for the birds to smuggle in. The other thing about a Bristol Herc is that there is no such thing as a nook, and no such thing as a cranny. The clean up was very straight forward with tons of room for me and my rake and towards the end, a leaf blower. The core engine itself is remarkably well preserved. A soapy water blast will remove the bird poo that is on the reduction housing. I'll follow that with a high pressure kerosene/light oil mix to get in amongst it while the difficult bits are assessed. By these I mean the mags and carburettor. It is hard to say what attention these will need. Mags are mags and as long as the points are clean and adjusted and the booster coil does its job, they should be OK. The ignition harness may be another story but like a lot of things on this project, we will probably only find out when we flick the switch. The carb might be a source of headache as it is not a simple float and jet out of a Cortina. The carb is a monster of the best of the worst that Claudel Hobson, Stromberg, Bendix and Briggs and Stratton could ever hope to combine. It is a pressure carb that is fed at 30psi by an engine driven pump and uses fluid pressure for servo operation of boost and mixture control. It also senses exhaust back pressure and adds that to its fuel air equation. It even has engine oil passing through the throttle butterflies for anti-icing. Internally, diaphragms control a lot of what goes on, when and how much. I am in two minds about whether I would ever open one up even if spares were available. One mind says "na man don't go there" and the other mind says "don't you dare!". Hopefully when the time comes, we will find out that the fuel system inhibiting will have been sufficient to enable the engines to run. I talked to a former SAFE Air engineer yesterday and he said they NEVER tinkered with a carb. There were two reasons for this. 1, they hardly ever needed to. 2, if there was a problem the carb was sent to the overhaul agency for repair. Each engine has a collector tank in the nacelle which receives fuel from the three tanks in each wing. Fuel will be a large consideration for obvious reasons. Two guzzling radials, massive fuel tanks and a limited budget. Research today showed me that there is a ferry feed to the fuel system which allows a fuel feed from the cabin. I am reluctant to use the wing tanks for the fact that say, 200 litres might only just wet the bottom, let alone provide a reliable feed. A 44 gallon drum with a booster pump would probably see us right. ZK-CPT is one of the few B-170's remaining with aluminium fuel tanks as opposed to rubber bladder tanks. That was one of the reasons she was selected for preservation. ZK-CLT that went to the RNZAF museum had to get new tanks made prior to her sale to Canada. I could spout engines, engines, engines all day but I am aware that there is more to this than chunky old radials. There is also an airframe, systems and electrics that need to do their bit. To this end, a few of us hooked up a battery cart the other day. It felt a bit like waking up the pissed uncle at a family Xmas party - you never know what you are gonna get. The Bristol has a number of traditional British ground/flight clunky 'switches' that you would expect to see on the national grid and a start master switch. With power applied to the aircraft a switch labeled ‘accumulator’, controls a relay that turns the power on. On this day, I rustled up a few mates to help out with the big awakening. One was on the battery cart, one in the aft fuselage, one in the cabin and me upstairs. A couple of fire extinguishers were at the ready in case the wiring decided to give up. I must admit I was expecting the dignified click and whizz that I get everytime I flick the master on the B1900. What was I thinking? A Bristol Freighter doesn’t do ‘click and whizz’. A deafening ‘railway crossing bell’ down in the cabin let us all know (both at Omaka and in downtown Blenheim) that we had awakened a monster. The Bristol has a bell that gets the attention of both crew and passengers above the din of an un-soundproofed cabin nestled between 4000 piston horsepower. On a quiet Autumn day, it certainly got our attention! Before we do that again, we must find the switch that turns it off….. Along with that, the wipers started flack-flacking across the windscreens, a number of gauge needles flickered, lights lit up, warnings annunciated and for a few seconds it was all a bit too much to take in. Off went the switch as I gathered my thoughts. A voice from down below asked, “Al, did it do anything?” “Ah yep!”, I replied. “Did ya hear that bell?” the voice said. “Dude I can still hear the bell!!!”, I barked. “Loud eh?”. A number of airframe to engine linkages are a bit stiff and need a bit of attention. I’m yet to suss out the condition and operation of the number of electrical booster and priming pumps and solenoids that are needed to supply the pressure carbs. The manuals held by the AHC detail a number of hours based periodic servicings and I will soon identify which is the most appropriate for our project. I tend to think that the deeper the better. We will have a hell of an audience when we flash this thing up and I like to think that if we do enough, well enough she will burst into life, run happily enough for several minutes and we will all adjourn to the bar for cigars and medals! There are a number of what-ifs and I am working my way through them at the moment. The next task is to fabricate a spanner to get the HT leads off the spark plugs and poke a boroscope into the cylinders. One problem that sleeve valve engines have is called ‘sleeve nip’ and it is where there is excessive friction in the cylinder sleeve that the boss that secures the sleeve to its drive crank can fail. Hopefully a lung full of penetrating oil in each cylinder can sort this out before we turn the engines. I do believe that if this project is done thoughtfully and carefully, ZK-CPT will no longer be a silent example of NZ’s aviation history. Watch this space!!!
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Post by Bruce on Apr 1, 2008 20:35:23 GMT 12
Sounds good Al, however be warned these sort of jobs will always expand to suit the resources available - plus a bit more! The sea fury didnt have the inner cowls you describe, but the cooling system on the Bristol is a bit different anyway - if I recall there is a fan behind the prop to force air past the birds nests... As you say, Bristol doesnt do fiddly and timid!. I know the sort of tool you need for the HT leads - its a sort of split socket on a spanner with drive keys thingy The one we had for the Centaurus looked like it was half fossilised and had come out of the ark - although most likely it came from Dwens! I would imagine that by the end of the aircraft's service life SAFE would have rebuilt the harnesses with newer spec wiring than the original stuff which deteriotaed quite badly - if so you mightn'y have to do too much to that. the carb is a bit of a worry though - give a bit of a clean but stay well away from pulling it apart! you need special test rigs to get it all calibrated back properly, and the Worlds only remaining Bristol fuel system test rig is held by Vintech at Little Gransden in the UK. If it doent look good, you may have to see if Dwens will part with one of theirs without asking an arm and a leg or two. Sounds an exciting but highly achievable project - Go for it - Roy Fedden would be proud! (it it was supposed to be easy, everyone would be doing it...)
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Post by skyhawkdon on Apr 2, 2008 6:50:57 GMT 12
Al, love your work - you could be a writer! Please keep up the commentary it is fascinating. Wish I could help out with the electrical side. When I did my Techs Course (1986) they had a full mock up of a BF electrical system at 2TTS at Wigram which we had to fault find when we did our electrical trades test. I wonder where it is now? Might be worth making some inquiries at GTW. They might still have a few electrical components/parts as well as technical notes.
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