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  • He Who Shall Not Be Named
    replied
    Originally posted by Das Boot View Post
    Thanks a bunch for the excellent work. The boat will outlast me. Lol.
    My pleasure, sir. We'll tear 'em up this boating season!

    Leave a comment:


  • Das Boot
    replied
    Thanks a bunch for the excellent work. The boat will outlast me. Lol.

    Leave a comment:


  • He Who Shall Not Be Named
    replied
    The hull halves matted up; the WTC populated with working devices and certified operational; the entire boat was then taken through the harrowing process of adding fixed ballast weight and buoyant foam to make it stable, maneuverable, and to assume near neutral buoyancy submerged, and to float at the correct waterline when surfaced. Easily said. Not so easy to do!

    All that, and more, before its first open-water tests. The open-water test did in fact reveal one last goof that had to be corrected before the model could be sent off to Casey for him to paint and add to his fleet.

    Here I'm installing about 1-pound of fixed ballast lead weight low in the hull, well forward, to place the submarines c.g. at its longitudinal center. I have yet to install the buoyant foam in the nose and within the upper hull to counter that weight with an equal amount buoyant force.



    As there was only about a 1/2-inch annular space between the hull and WTC I had to install the initial hunks of buoyant form -- each shaped with convex and concave surfaces -- to fit that tight space. A cardboard template used to mark off those curves to these closed-cell foam blanks.



    I knew from experience that I would need a lot of flotation near the bow; these preliminary hunks of foam were installed long before any in-water testing. Only after the in-water tests would I fine-tune the amount and location of the buoyant foam elements within the hull.

    All foam pieces were secured in place with RTV adhesive. Quick and easy to break if, and when, the need comes to remove and/or replace/relocate buoyant foam pieces during the trimming process.



    Initial trimming was done in a big trough of water just outside the shop. First, I worked out how much foam, and where it had to be located to get the model to suspend itself totally submerged with the ballast tank full of water, the boat statically stable with no roll and a zero pitch-angle. I then blew the ballast tank dry and noted how high, or low its waterline was, compared to where it should be. Moving foam either above or below the waterline -- a trial-and-error process that can go quick, or not so quick -- until the model submarine sat with the waters surface right at the designed waterline.

    Trim for submerged trim first. Trim for surface trim last.



    Here's the layout of buoyant foam after achieving correct submerged and surfaced trim.



    The submarine was now ready for open-water tests. Here, everything needed to support that activity has been assembled and ready for its ride to the local Jewish Community Center outdoor pool. Show time!



    Here's a quick video clip of the JCC pool tests. Things went very well. But, after arrival back at home I found about a spoon-full of water in the WTC's after watertight space. ****! A leak. Gotta fix that...

    https://youtu.be/C_0tq0GBdZc

    A quick look-see at the dry side of the motor-bulkhead showed some water weeping out from between the motor-bulkhead and its back-plate, which holds the motor in place. Looks like a bad motor shaft seal!

    Break out the tools... going to be a late-night fix.

    !#@^@&*$)^&(%$^%$^##!



    The three servo pushrods were pulled; the aluminum tray and bulkhead with attached devices was unscrewed from the back-plate; the ESC leads to the motor de-soldered; the receiver antenna lead undone from the antenna stud; and the DC and LPB hoses pulled from their nipples. Now I had access to the motor-bulkheads internals.



    I removed the back-plate and found water still gathered in the well where the motor pinion and motor drive shaft spur gear resided. Yup! Water was getting by the shaft seal. Nuts!



    Turns out I failed to properly polish the shaft and a small burr chopped up the inboard lip of the rubber cup-seal. The shaft was turned and polished, and the cup-seal replaced.



    Note that with a cup seal only a very narrow internal and external lip makes contact with the seal body and shaft -- any deformation of the shaft or body, or tear in either of the seals lips will offer a path for water to get by the seal.



    Before installing the new cup-seal I thoroughly cleaned out any gunk from the space where the cup-seal resides.



    A liberal amount of silicon grease is packed into that space, and the new cup-seal jammed in place, followed by the motor-shaft, and re-assembly of the entire motor-bulkhead.



    The entire WTC was once again leak checked and operated successfully before packing things up for delivery to my boating buddy, Casey.







    Whew!... glad that's out of my hair.

    Now!... on to Kim's HUNLEY project.


    Leave a comment:


  • He Who Shall Not Be Named
    replied
    https://youtu.be/FYIjy6GB-M4

    https://youtu.be/4tQ-jRXSFAI

    Leave a comment:


  • He Who Shall Not Be Named
    replied
    https://youtu.be/C_0tq0GBdZc

    Leave a comment:


  • SteveNeill
    replied
    What a pleasure to watch the good work.

    Leave a comment:


  • Das Boot
    replied
    Excellent.

    Leave a comment:


  • He Who Shall Not Be Named
    replied
    Today... FINALLY!... I put Casey's 1/96 SWM BLUEBACK into a sizable hunk of water and worked out the bugs. Almost there. Tomorrow, I go back to the JCC for some u/w shots from a tow-body and a camera strapped to the deck of the model. Stay tuned, sports-fans!

    https://youtu.be/bAs2TD9DRMM

    https://youtu.be/hD8oVDfd2Gc

    https://youtu.be/l3VKdHyUi_c
    Last edited by He Who Shall Not Be Named; 02-28-2022, 08:25 PM.

    Leave a comment:


  • george
    replied
    In a way it does trap some animals, two legged ones which like the guts inside.

    Leave a comment:


  • JHapprich
    replied
    ...and who of you has ever been asked by someone passing by if that's an animal trap, too?

    Me: Every single time!

    Leave a comment:


  • george
    replied
    Originally posted by He Who Shall Not Be Named View Post
    What's the point in assembling a complicated, practical, beautiful looking r/c model submarine only to have it damaged and defaced during transport and later storage as you shift your attention to other matters?

    I answered that rhetorical question long ago by making it a practice to provide each of my r/c submarine models with its own, custom built, transportation-stowage box.

    Illustrated below are just a few examples, their lids removed to show the contents. Note how soft foam-board frames are used to cradle the model, the hull centered in the box.

    Not shown here, but each box lid has attached to its underside a like array of foam frames, each contoured to girdle the models upper works, just as the lower set of frames supports and girdles the models lower works.



    No big deal. A transportation-stowage box is, after all, just a six-sided,1/4-inch-thick exterior grade plywood container, reinforced at the edges and corners within by 3/4-inch square wooden molding, and outfitted with 1/2-inch-thick insulation foam frames cut out and arranged to support the model within.



    Ellie and I, over the years, have built and worked with small, medium, and stupid-large transportation-stowage boxes. Those boxes serving one major purpose: to protect the contents from damage, no matter how the box is bounced, shoved, inverted, and dropped.



    My model boating buddy, Phil Kordich, built this box. It's fine for the most part, but there is no provision to stabilize the model within should some fool load the box upside-down, or the box should tip over for whatever reason.

    No. I found the only sure-fire way of protecting the model is to cushion it from force applied in any direction; it is my practice to literally cocoon the model in protective foam framing and structural webbing.



    The job, of course, starts with the wooden box. Big holes in the sides permit air to flow freely within. That's an important feature as often the model is put in there still wet from a run at the lake or pool.

    As to the box dimensions here's my rule-of-thumb (these are inside measurements):

    Length is model length + 2-inches front, and 2-inches at the back.

    Width of the box is width of the models maximum appendage projection + 1.5-inches each side.

    Height of the box is the height of the model from keel to top of sail (masts stowed retracted or removed) + 2-inches at the bottom +2-inches at the top.

    In addition to the foam sheet frames I'll also provide foam sheet structural webbing, top and bottom, to lend further support of the model within the box and to also stabilize the frames.



    The lower array of frames and webbing is glued to a 'floor' made of the same insulating foam as the frames and webbing. This floor sits within the bottom of the box and is removable. The upper array of frames and webbing is glued to the bottom side of the boxes removable lid. That lid is secured in place with deck-screws that run into the molding strips atop the box.



    First item cut out from the sheet of insulation foam is the floor, which is marked for locations of lower foam frame pieces which will be epoxied to it once they are cut to contour with the bottom of the models hull. Same will be done for the upper half of each frame, but those items will be affixed to the bottom side of the boxes lid.

    As the hull section geometry is constant through most of the submarines length, most of the frames will be cut out in an identical fashion. Only at the bow and stern will special frames be required because of the hull tapper at those points. I've already started in on a cardboard template that will be used to mark out the frame cut-outs -- having lofted off the sectional form of the submarine with the aid of calipers, compass and other drafting tools.



    Using the paper template to mark out the cut-outs to the frame blanks. Each frame will be divided into an upper and lower half, the split occurring at the centerline of the submarine.



    The floor is set into the box and the bottom halves of the first two sets of frames are positioned within and the model carefully lowered into the box. All this to validate that the model is properly centered within the box. That check completed I can, with confidence, finish cutting out the rest of the frame blanks.



    The band saw, equipped with a very narrow blade, capable of tight radius ruff cuts, makes quick work of punching out the centers of the foam frames. At this point the frames have not been cut into halves.



    An oscillating vertical drum sander refined the cut-outs. Once cleaned up each frame was cut into an upper and lower half.



    With the aid of straight pins the lower half of the frames were epoxied to the floor piece.



    The model was then plopped down onto the frames, and I began the laborious task of lofting the geometry of the bow and stern stations off the model. That dope needed to start work on producing accurate (Ha!... never happens the first time!) cardboard templates for the bow and stern frames.



    Cardboard section templates for the upper and lower forward frame. Note the tight, perfect fit with almost God-like accuracy... achieved after only five previous, unsuccessful attempts! This method is more gosh-and-by-golly than science, I can assure you.



    With all bottom half of the frames glued to the floor, the floor was inserted into the box and the upper half of the frames pined atop their counterparts at the bottom. I then applied epoxy glue to the top edge of each upper frame half, sat the lid in placed, and drove all of its deck-screws down tight. This permanently bonded the upper frame halves to the bottom of the boxes lid.



    The lid was pulled clear and foam structural webbing installed.



    Done! Now, back to fun kit-assembly chores.

    The transport boxes are as Good looking as the model they are made to protect!

    Leave a comment:


  • He Who Shall Not Be Named
    replied

    Well, my buddies little 1/96 BLUBACK r/c submarine is almost ready for trimming and sea-trials. All I have to do now is cut out and install some flotation foam in the hull -- an interim measure. Final amounts and location of the foam will be determined through experiment in the test-tank.



    Note how the forward running leg of the sail-plane pushrod, situated within the top of the upper hull half, terminates aft in a magnet, which -- when the two hull halves are joined -- links to the center magnetic coupler projecting aft from the lower hull half WTC's motor-bulkhead.



    With everything an operational model submarine must have aboard, a trial amount of fixed lead ballast weight in installed low and forward. The objective is to get the submarine to balance at its longitudinal center-point. For the smaller r/c submarines like this 1/96 BLUEBACK, about a pound of fixed ballast weight is a good starting point.

    Ideally the center of the ballast tank is also at the c.g. -- that situation desired but not absolutely required.



    The fixed lead ballast weights are there to position the vehicles longitudinal c.g. at the center of the hull, and to place the center of mass as low in the hull as possible. The c.g. at the boats center assures reasonable maneuverability; that mass low in the hull also makes the boat statically stable about the roll axis.

    Most submarines have no active means of managing stability about the roll axis. Therefor the boat has to be statically stable in roll. The magnitude of the righting force is contingent on the vertical distance between the vehicles c.g. and center of buoyancy; the greater the distance between those two points of force, the more stable the boat becomes about the roll axis.

    Should there not be enough fixed ballast weight, and enough buoyant foam to counter that weight, the distance between those two points of force will be too short and will not have the moment arm required to right the boat from a roll in a timely manner.

    Experience has taught me that so much weight in the bow demands a great deal of buoyant foam up forward.

    I turned this foam piece on the lathe, its shape conforming to the geometry within the bow.



    A blank of dense, closed-cell foam was cut out on the bandsaw and mounted to the face-turning plate of my Taig lathe. The eventual shape of this piece insured by use of a cardboard template that represented the inside of the model submarines bow.

    In background you see the upper hull half of the 1/96 BLUEBACK model. Note how the bow plane pushrod runs from the sail back to where its magnetic coupler eventually makes up to the bow plane servo linkage when the two hull halves are assembled. Also seen to good advantage here are the many 'capture lips' that work to hold the two hull halves in tight registration with one another when assembled.



    Turning the foam bow piece on the lathe. Note that I'm not using the X and Y drives of the cross-slide to cut the foam. Instead, I'm using the long shank of a tool to serve as a tool-rest for some hand-cutting of the work as its brought up to speed. Caveman, yes, but this method made the work go a lot quicker than if I had elected to drive the cross-slide around with the cranks. You can get away with such an expedient if the stuff you're turning is soft, like this foam, and no shop Supervisor screaming that you're 'unsafe' and a bad example to the other drones.

    (Thank God OSHA's agents have never goose-stepped across my shop floor. Oh, oh... did I just put myself on their radar?! **** 'em).



    From the day I integrated all the servos, speed controller (ESC), battery eliminator circuit (BEC), low pressure blower (LPB), r/c receiver, and the specialized devices produced by KME I was plagued by a twitching problem when I turned off the transmitter -- something was getting RF junk to the receiver decoder outputs; all mechanical devices (motor, servos, LPB) would dance around crazily and would only stop and resume normal operation once the transmitted signal was once again sent. I don't have the smarts or equipment to signal-trace, so I embarked on a week's long march to swap out components with ones I knew worked. All that effort in the hope that my Easter-egging would find the culprit of this 'glitching'. And I eventually succeeded. The bad guy was... thank you, Murphy!... the last thing I swapped out: the r/c receiver itself!

    A new receiver installed, everything working as it should, I finished setup on the BLM and that got me the fail-safe throw and delay I wanted for this model submarine. Sometimes you guess right. Sometimes you don't. This was one of those 'don't' times.

    (If I had access to a Terminator sized hydraulic press that bum receiver would have been reduced to a smoking, wafer thin Frisbee by now!).



    After installing the new receiver, I had to once again run through the rather complicated protocol of setting up the Battery Link Monitor perimeters. That single, relatively small device performs the function of battery monitoring; it also will command the ballast sub-system to blow the ballast tank if the r/c signal is lost or a low voltage condition exist on the main bus; and informs you of how many 'loss of signal' events occurred during the last run.

    The BLM isn't you grand-daddy's fail-safe... no sirree Bob! It's that and so much more. But, because of its multi-function design, setup is an exacting and most frustrating experience. Yet the instructions are not to blame as they are clear and methodical. But! You have to follow those instructions to the letter, or you won't get the results desired.



    The KME Depth Cruiser (DC) device automatically positions the model submarines bow or sail planes to maintain the last depth ordered from the transmitter. It measures the hydrostatic pressure at the keep level of the submarine and works to autonomously drive the planes to keep the submarine at that depth. However, for the device to work its pressure sensing pick-up point (on this model in the form of a brass intake tube glued to the bottom of the hull) has to be well forward of the vessels center of gravity. A length of flexible hose runs aft to the WTC's motor-bulkhead where it terminates in a brass nipple. On the dry side of that nipple, within the WTC, a shorter length of flexible hoses connects sea pressure to the DC's pressure transducer.

    You can turn the DC on/off from the transmitter. When off you have direct control of the planes. When 'on' you still drive the planes from the transmitter, but once you put the stick to neutral, the DC remembers the depth there and takes over the planes to keep the boat at that depth.



    A water filled length of flexible hose was used to verify the sensitivity of the DC as well as to affirm that the sail planes would travel in the appropriate direction as a consequence of a change in depth. Just 1/4-inch of vertical travel of the water column gave me either full rise, or full dive on the planes.

    Impressive!... MOST impressive!

    With an angle-keeper working the stern planes, and the DC working the bow/sail planes, a well-trimmed submerged submarine model is hands-off as far as depth management is concerned, all you have to do is steer. A most remarkable gadget. And setup is easy.



    With all WTC sub-systems running properly time had come to test the Lexan cylinder, seals, and bulkheads for water tightness. The equalization core valve (a common tire-valve) was removed, and a length of flexible hose made up so I could blow air into the WTC -- the slight over-pressure within the WTC would cause bubbles of air to escape from any leak points. The bulkhead O-rings and pushrod seals are the usual culprits when it comes to leaks, but I'm glad to report that the first tightness test was successful. I then moved onto a function test of the submerged WTC.



    The transmitter and WTC were turned on and the WTC submerged in the test tank. The ballast tank was vented, flooding it.

    First, the 'normal blow' as commanded from the transmitter. The end-point adjustment had been made to the transmitter so that the ballast sub-system servo traveled only enough to turn the LPB motor on. The OPB pushing compressed surface air into the 'soft' ballast tanking blowing the tank dry.

    (It's called a 'soft' ballast tank as it does not see much of a differential pressure between its interior and the outside environment because it is always open to sea through two large flood-drain holes at its bottom).

    Next, operation of the 'emergency blow' function was tested by turning off the transmitter -- representing a loss-of-signal to the WTC's receiver -- which caused the BLM (acting in fail-safe mode) to position the ballast sub-system servo to full travel, which not only switched on the LPB (which would be useless as its air induction intake would likely be well underwater in a real-life situation), but also engaged the emergency blow valve, releasing propellant gas into the ballast tank to blow it dry.

    All checks and test completed to my satisfaction; the WTC was certified for use aboard the BLUEBACK.

    Now to trim the entire assembly for proper surfaced and submerged trim.



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  • He Who Shall Not Be Named
    replied
    Originally posted by Das Boot View Post
    That boat is too beautiful for a scum line.
    Right you are, sir! But, I have another 571 in the works. From a kit produced from no other than our own Type-23 cut-away maestro, Dr. Schmidt. A wonderful GRP, resin, and metal kit in almost 1/96 scale. Here are some shots of this beauty:



























    I have pretty much finished it, but have not painted it yet. Already had it in the water and it's a good runner indeed. Here's some footage of that:

    https://youtu.be/zRdQ-h9sORE

    David
    A wonderful kit, Doctor

    Leave a comment:


  • Das Boot
    replied
    That boat is too beautiful for a scum line.

    Leave a comment:


  • goshawk823
    replied
    Originally posted by He Who Shall Not Be Named View Post

    Yes. Phil's moved out of state now. Last I heard it's still operational.

    David
    Saw him a few years back at the IPMS show here in Richmond and chatted for a couple minutes. Hadn’t realized he’s not in VA any longer.

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