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SimonBrown

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  1. Very much depends on size, complexity and location. This one took about 8 minutes to shoot the 224 images, 30 mins to sort and prepare for processing into 3D and then about a half day of computer time to actually process. Underwater is an altogether different amount of time, varying from days to months to get the final result. Can be done for less time, but compromise will always be accuracy, level of detail etc.
  2. Well, in spite of not finishing the rebuild of the 21 inch 8-cylinder radial torpedo motor I seemed to acquired a second example... This one is 18" in diameter and comprises of the motor, driveshaft and rear prop guards. It was lifted from the sea years ago and all the ferrous parts have corroded to dust, but the bronze castings are under the crud: 18in Torpedo drive train Judging by the presence, design and material of the prop guards this one is likely to be a very early example and possibly an air-dropped variant - the kind of thing used by Coastal Command or hung under a Swordfish. Equally, it could have been from a destroyer or MTB and we do have the wreck of an MTB in Weymouth Bay. I'm very unlikely to get the time to clean this one up and leaving it sitting on the drive is not going to happen, so I may be tempted to part with it - if there are any takers?
  3. In no way can this be described as a military vehicle...but it is a defensive structure so hope its of interest... I'm working on a project that is demanding a lot of testing of new techniques and methods, and the outcome of which is a level of accuracy and detail that has pushed some boundaries. Its all techie stuff so I won't bore the pants off everyone but basically it involves embedding GPS data into the image at time of capture. This will explain in part why the 8-cylinder torpedo engine has taken a back seat and gone quiet. Anyway, needing a subject to test on my thoughts turned to using the pillboxes that line the Basingstoke Canal as a reference and here you go: Type 24 Pillbox There are many examples tucked away in hedgerows fields around here, serving as a reminder of a battlefield that - thankfully - never was.
  4. Seeing this dug into the memory banks... I worked on a modified AFV432 project at RARDE Chertsey a long time ago. The K60 engine had been removed and a 6-cylinder Cummins unit with variable geometry turbocharger fitted to the crew compartment. The driveshaft ran forward into the steering box...right past the driving position. The tank shop foreman insisted we made up a guard that would retain the driveshaft in event of any failure of said shaft. It was a very substantial hooped bracket. In due course the driveshaft did fail whilst the engine was under max load...had the guard not been there to restrain it the damage to the driver would have been described as "life changing injuries" as it flapped around unrestrained. Looking at that driveshaft running across the hull and its proximity to the drivers legs triggered this memory...and if you have not already done so...do please consider a guard or restraint to limit how much damage the driveshafts could do in the event of a failure. Apologies if its already in hand, but it would be remiss of me not to share this experience I think.
  5. Agreed. Slab Common used to be (might still be...not been there for a while) full of hulks used to practice recovery I believe. This hulk was not there, but in an unusual location one would not normally associate with armour in the modern times. So I will take a trip over there sometime I think.
  6. This entry caught my eye: MkVII Bridgelayer Recently unearthed south of Bordon Camp in Hampshire In very poor condition but possibly to undergo a comestic restoration to provide a gate guardian. Does anyone have any details on this? About 10 years ago whilst out mountain biking on the lands near Bordon I came across a small hole dug into the side of an earthen mound. In the hole was a large section of steel armour, possibly with a suspension mount, that featured the kind of hole only an anti-tank round can make when it does its job. I had forgotten all about that until reading the above...I must go back and investigate soon.
  7. Diameter and pitch of the prop would be my first check.
  8. A chance to scan an Alvis Scarab/Acorn into a 3D model arose this week when I paid its owner a visit: Alvis Scarab/Acorn Charming little vehicle with a great history. The same owner has the Series III Carawagon and the results of scanning (for fellow forum member Robin) that will be processed and published soon.
  9. There are three of these vehicles on the SS THISTLEGORM? I know it doesn't help much...they are in 25m of water, are in Egyptian waters and a massive tourist draw to 1000s of divers... But if I can scan it - and there is every chance I will be back there - then I'm happy to help if I can. Whereabouts on the vehicle are they fitted? Failing that, I could scan the existing pump into 3D and then mirror it in CAD?
  10. Many thanks Robin & terryb for the words of wisdom. All good gen and thoughts. A few more questions: Registering and ex-MOD example for the road - any issues with Construction and Use? If I recall the rear body is held on with four bolts and can be quickly demounted - is this memory correct?
  11. Excellent thinking on why the valve stem is so fat...and whilst I think the reasoning is spot on, its worth bearing in mind the design of the engine. The inlet valves work the other way around to any normal internal combustion engine; The flat face of the valve would typically face the combustion gases. Not so in this engine...here the inlet gases are pressing against the flat face of the valve...so the large diameter spring is actually holding the valve closed during combustion/power stroke and the expanding gases inside the combustion chamber. Inlet pressure alone is exerting a force that would hold the valve shut in this case. Did that description make sense? Have a look at the photos in the 1st March post here: Inlet valves etc I hadn't realised just how unusual this is, until your really thought-provoking post rory57 - so many thanks for that. The more this engine is understood, the more whacky it gets. So far, everything I read hints at an inlet pressure of 160psi as supplied by the air tanks, regulated down from the 3000psi or so they were charged to. Interesting, as it appears there was a shift in design thanks to improvements in the strength and quality of steel to hold progressively higher pressures. More reading needed. Now that does sound interesting - got any pictures yet? That would make the number of 8-cylinder torpedo engines I know of go from 2 to 3 and it would be great to see what it looks like. My engine measures 20" over the cylinder heads, leaving just 1/2" as a sliding fit into the torpedo body. Be interesting to know what the 18" actually measures?
  12. This is a long-term project, but the nagging idea of owning and operating a Bv206 under consideration. Buying: What to look for? Known issues or faults? Track life/wear? When are they knackered? Types and variants. FFR an issue? Spares - prices and availability? Operating: Petrol vs diesel? Anything really whacky about either? Reliability? From what I recall, very good...but thats 20+ year info. Maintenance - engine & drivetrain - any issues? Maintenance - steering & suspension - any issues? What license is needed? Not steered by tracks, so not an H type? Genuinely interested...and would love to hear from current owners. With that, its over to the forum and its collective knowledge...
  13. Sure, understood. Irony and humour is one of the hardest things to convey on t'internet. There is a third and far more accessible vehicle on the upper cargo deck. I will dig out some images. Correct on the loss of life. Some of the RN DEMS gunners and ship's crew were sleeping on on the holds when the bomb landed, according to accounts at the time. Angus McLey's George Medal citation makes humble reading. Generally, divers are not messing around with the munitions. There are a few 4in shell cases that have had the base plate buffed up to reveal the crows foot, date of manufacture etc but for the most part divers have no idea what they are looking at, let alone fiddle with it. There are some 15" shells near the aft end of what is left of hold No 4 but with marine growth many won't realise what they are looking at. No 5. hold was crammed with boxes and boxes of 4in shells, and the seabed is littered with boxes and individual shells thrown from the wreck by the explosion. As long as its left alone underwater UXO is pretty benign and the depth of hold No4 & 5 generally limits the time most divers can spend here. Plus most dives are done with a guide leading a group around the wreck. Most divers swim by without realising its all there, or have it pointed out by a guide as they swim by. So in terms of risk, by far the biggest risk to loss of life is all due to the divers themselves and right at the top of the list is running out of gas. In the time I spent there I saw two individuals hanging off the dive guide's alternate air supply as they had drained their tank. The underwater world punishes mistakes quickly and thats before anyone has even realised there are tons of bang in the aft end of the ship. Ah yes, the Montgomery. If that lot ever high orders, the east coast of Kent and Essex will be a little different. The longstanding policy has been to leave well alone...if that is a sensible long-term strategy remains to be seen. I'm glad I do not live on Canvey Island. Could we leave the Thistlegorm alone? Aside from the munitions there are few comparisons between the two wrecks. One sits very challenging conditions, almost akin to very cold, liquid mud. One is located in tropical blue warmth. The location makes a dive on the Thistlegorm as about as easy as it can be and its a very popular dive. One day we had 7 boats moored alongside ours, each with 15~20 divers aboard and all doing at least two, possibly three, dives. Attempts to calculate the simple economic value of the wreck has been attempted over the years, but with that volume of tourists willing to spend hard foreign currency in what is a relatively poor country the chances of the Egyptians closing the wreck to divers is at best guess close to nil. Besides, most divers want to see the vehicles in the forward holds. Helps keep interest in military vehicles alive...which is no bad thing.
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