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Ian_Grant

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Everything posted by Ian_Grant

  1. Ian_Grant
    Bill, I believe it is an elongated chain link in the centre, but when pulled between two links oriented parallel to the side of the ship it naturally orients itself perpendicular to the side of the ship, and the viewer then cannot see its two bars.
  2. Ian_Grant
    I should have mentioned these five circuit board prototypes covered in socketed TTL were entirely wire-wrapped (giving away my age here). That added another dimension to debugging/modifying. Fond memories...!
  3. Ian_Grant
    Thanks gsdpic for the explanation......problems with hardware/software are all perfectly logical in the end, when you find them at last. I spent my career on hardware. I used to think to myself when debugging a problematic PCP "There's always a logical reason...". This is a great digression but it's something I never forgot: Early on in my career, in the 80's, I was assigned to design a prototype Viterbi coding system to provide anti-jamming capability in a military radio system. Nobody in the engineering group knew anything about Viterbi's scheme so I started by reading his original IEEE paper. I designed a larger prototype according to his example small design, but worryingly I did not quite fully understand the math behind it all. My colleague meanwhile designed a companion gadget to inject random errors in a data stream, at a desired rate, in order to test the Viterbi prototype. We found that the prototype was correcting errors in incoming data, but not as many as it ought to have been. I was about tearing my hair out fruitlessly probing around for problems, could not find any, and finally as a last ditch attempt went through the math board chip by chip (this thing consisted of five PCP's entirely built from MSI TTL) with IC clips and a logic analyzer until I found an octal flip-flop one of whose output pins went high if clocking a "1" through but then went low again at the falling edge of clock, for some reason. One quarter of the decoder's calculations went through this register and were thus corrupted, spoiling the error-correcting performance. The powers that be were threatening to cancel the project even though I was ahead of schedule (probably convinced I knew not what I was doing 😆) so it was a particular triumph to replace this chip and see the error correction performing as expected literally minutes before a departmental lunch with visiting suits. In fact, my manager poked his head into the lab to tell us we were leaving for lunch just as I threw my arms in the air, shouting "YES!". 😃 One of the great moments in my career.....😊
  4. Ian_Grant
    HAHA!! Yes, I've had problems with nested IF's so I try to avoid them. In this case I found through judicious insertion of Serial.print statements that the program was running all three IF statements every time it looped. Compiler decided that my garbled conditions were true, every time. 🤪
  5. Ian_Grant
    No, I had for example: if (minsweep <= sweep <= catchend) { etc etc which would have been fine on a math test, I just wasn't thinking. whereas it should have been: if (minsweep <= sweep && sweep <= catchend) { etc etc
  6. Ian_Grant
    Thanks Bedford for following and your helpful comments e.g. your prescient one about beefing up the u/w hull for the weight. As to commitment, I look upon this as a design challenge, something unusual, and it brings out the stubborn engineer in me. I spent my career "making stuff work". 😉 Not sure about the value for catch fraction.....don't want to waste too much of the stroke only partially in....need to see it in water. Might have to change program to run in slow motion for observation. Me too! I will get going on the hull this winter. I'm hoping to use the library's laser machine to cut out all the rib profiles and keel etc from baltic plywood. More software to blunder through...😬 Thanks Glen! I appreciate all those following along with this. 👍
  7. Ian_Grant
    You might not say that if you had seen me trying to run a little test program to check out my code for the "lift" values during the trapezoidal power stroke......wanted to make sure it worked before sending it to a servo. Basically my lift code placed in a "for" loop to run it through a cycle. Wasn't working as expected at all, thought the "for" loop wasn't set up right (first time trying one), changed to a "while" loop with no improvement, then finally realized I had messed up the syntax in the "conditions" of three "if" statements which sort between the catch and steady portions of the stroke (forgot "&&" between two comparisons in each set of conditions). Stupid error, however I can't understand why the compiler didn't bitch at the strange input. In any event it all worked out.
  8. Ian_Grant
    I wrote a little test program to move the servos to static positions, according to numbers I type in and which the Arduino uses to set their control pulse widths in microseconds. I was then able to inch the servo arms along to decide on their extreme positions given the physical setup. Arduino provides a "map" instruction which is used to scale a variable's range into a new range with all readings adjusted proportionally. The guts of the program assumes full movement of the servos, and at the end they are "mapped" into the limits found as above just before the pulses are output to the servos. When I have a ship I will use the test program and again "map" to its physical limitations, on a per-side basis. I also changed the software to have a better stroke shape. Originally the stroke was simply rectangular, with the lift servo moving abruptly up or down at the ends of each sweep. I added a "trapezoid" stroke shape. The entire return stroke is flat; the power stroke consists of a ramp down into the water to full immersion, a central flat portion underwater, then a symmetrical ramp up out of the water. The ramps, or "catches", are defined by a new variable "catchFraction" which is the ratio of the two ramps to the overall sweep length. "catchFraction" is entered at the start of the program before compiling. I use one of the DIP switches on my daughter board to dynamically select between these strokes. Enough words, here is a video. The oars are run with "catchFraction" =1.0, then with a value of 0.4 to demonstrate.
  9. Ian_Grant
    I know the buildings you mean; I've pedaled past the one on the lake many times. It's a shame the one on #2 near Abbott isn't being used for something. It looked so much better when someone repainted the front years ago but they apparently couldn't continue (red tape from council?). Still a great place to be though. *End of digression*
  10. Ian_Grant
    Just so long as they aren't going to nail you with "brokerage fees" or whatever. 😬
  11. Ian_Grant
    Dave, your model is very very nice! Sorry to be so late to your log. By the way, my mom and dad retired to Cobourg, away from Bramalea thank God, and what a pretty little town to be in! We all loved the beach and the ice cream place beside it. I used to cycle a loop up to Rice Lake and back when visiting; the descent back to Cobourg was always exhilarating!
  12. Ian_Grant
    Your kit must be from a different lot, Bill. Mine was still molded in funky black, red, and blue plastic. Your muted tones might be easier to paint!
  13. Ian_Grant
    I always enjoy a Victory build, and there aren't so many at this scale. Are you aware of Noel Hackney's little book on Victory, in the "Classic Ships and how to model them" series? His book is written for builders of your airfix 1/180 model and provides many many "upgrade" suggestions as well as complete rigging instructions. Well worth the price. Meanwhile, I look forward to following you.
  14. Ian_Grant
    Well, Nelson did chase Villeneuve across the Atlantic and back a little while before Trafalgar (Victory's only trans-Atlantic voyage, memorably painted by Geoff Hunt); maybe he bought some Bourbon in the Caribbean somewhere....😄
  15. Ian_Grant
    They're great Bill! I love the cargo being swayed aboard - rum barrels? Lime juice? Two thumbs up from me 👍👍
  16. Ian_Grant
    Yes, Ottawa is beautiful. Thank God I was hired here straight out of the University of Toronto and so was able to kiss goodbye to traffic-choked "T.O." forever. Wonder which parts you saw on the show? Rockcliffe Park perhaps? (A wealthy enclave). (I don't live there). 😃Although I did once work on a job adding walk-in closets in the basement of a tech-megamillionaire's house in there (he flies a WW II Spitfire, amongst others in his collection!). Have you visited here at all Bill? If you like the outdoors it's a great place to live. Bicycle paths along the rivers and the canal, as well as through various neighbourhoods; great swimming in lakes 1/2 hour across the river, fantastic x-country skiing just across the Ottawa River in Gatineau Park (about 200km of well-groomed trails which can be hiked in the summer); several local ski hills plus Mont Tremblant 3 hours away; a plethora of skating rinks (I can think of eight surfaces within 10 minutes of my house) plus, even better, outdoor skating on the frozen canal (8 km one way) in the winter, also groomed, weather permitting. And this town is just not that big so it's easy to get out into the country. Maybe I could get a gig with Ottawa Tourism? 😄
  17. Ian_Grant
    But doesn't nail polish reek like model airplane dope?
  18. Ian_Grant
    She looks Great Bill....but not quite so fast....😁....the bower anchor shank should be above the middle gun deck ports - see the pic of actual ship in #1419. You may find it difficult to hang the anchor in the shoe while having it this high, I know I did because the tip of the fluke caroms off the hull before its fat end sits in the shoe. Something wrong there! I think I trimmed a little off the fluke's tip to get it to hang. Once you lift the bowers up a little, you truly are done....😃👍🤙 Looking forward to following your SR build! It's been great fun. Regards, Ian
  19. Ian_Grant
    So does Chris Coyle. 😄
  20. Ian_Grant
    Yup, we encountered no less than seven cement trucks coming from Hana, usually on a hairpin bend. I was starting to wonder if there was a cement truck factory there. 😄
  21. Ian_Grant
    Highly original, as always! 👍🤙 That second symbol we ran into in Hawaii, when people were giving me it when the Hana highway on Maui dropped to a single lane at one of the many narrow bridges and I yielded. 👀 I asked one of our rental owners if they were in effect giving me the finger but apparently it means, loosely, "Stay cool". Interestingly one of the characters flashed it on CSI:Hawaii last night.
  22. Ian_Grant
    You've got it. Even if you add the buoys you don't necessarily have to add the coils. At sea the buoys would not be rigged, just hanging on the shrouds out of the way. I just connected one to show what it was. Rather like the way they hang each anchor on the real ship differently, to show the different stages of catting and fishing.
  23. Ian_Grant
    **** This post is mainly a note to myself as an aide-memoire in the event that I lose the napkins I did these calculations on **** So the set of three drawer slides under the aluminum channel weighs 0.38 kg. Eliminating them on two sides saves 0.76kg. Almost exactly half the weight in excess of that of the "Lion". I estimate I get 1kg (2.2lb) additional displacement for each 1/4" increase in the galley hull's depth. That's without making the bilges fuller. To add the 4.64kg of additional displacement required, keel depth (if keeping the slides) must increase by 1.2". That seems a lot. I can gain an additional 0.7kg by making the bottom flatter and the bilge fuller. Remember that Lion is all 1/32 ply skin and no fiberglass (since all ply panel joints fall on ribs or stringers). If I plank the galley which means F/G exterior it could be heavier. God, what a guessing game🤣😢 **** End of Note ****
  24. Ian_Grant
    Well, 4-1/2 feet, 5 feet; near as dammit after 40 years out of your sight! 😀
  25. Ian_Grant
    Hi Bill, that's the line to the anchor buoy hanging on the shrouds; it goes up and is coiled beside the buoy. It only looks like it goes to the block because the threads run very close together. The three blocks are the same rig as the three in your photo, except you have rigged your upper block in black. These are on the fore topmast breast backstay. The chain is the shank painter which I described in #1419.

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