Carl's Takao Build

Discussion in '1/96 Battlestations' started by dietzer, Apr 26, 2012.

  1. Tugboat

    Tugboat Facilitator RCWC Staff Admiral (Supporter)

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    Why does everyone's West System cure faster than mine? Even with 205 (Fast) hardener, it takes like 7.5-10 minutes to start congealing... Or is that fast? :)
     
  2. dietzer

    dietzer Admiral (Supporter)

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    That's fast to me, yes! :p
    One, because I was using small acid brushes, it was taking me forever to get each batch on the hull. Two, because I was working outside in the sun and increased heat shortens the cure time. Three, I'm used to using the slower 209 hardener, but all I could find around here was the faster 205 hardener.

    But mainly it was the small brushes and the faster 205 cure time. Using small batches of only 1 pump each of resin and hardener, I was still having each batch cook off before I could get it all on the hull...
    Of course, maybe it's just that I'm too slow... :D
    Carl
     
  3. NickMyers

    NickMyers Admin RCWC Staff

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    Mine always seems very slow to congeal, and there are days when I swear it thins out and runs after I think its thickening and stop paying attention to it.
     
  4. dietzer

    dietzer Admiral (Supporter)

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    I've had that happen to me with West Systems after it was more than 2 yeats old, but haven't had that happen with fresher stuff. The stuff I'm using now I bought last October, and it's working great.
     
  5. dietzer

    dietzer Admiral (Supporter)

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    OK, after a lengthy hiatus for business travel, I'm getting back to work on the Takao tonight. I managed to finish the waterproofing just before I left on my business trip. But I'm out on vacation next week , so I've only got about 4 weeks to get this boat put together and armed if I want to battle her Sept 7-9. :eek: That's going to be tight...
    My goal this week is to have the bow/stern hard areas done and the bottom sheeted and fiberglassed by the end of the week. That includes putting in prop and rudder shafts. If time permits, I'll get started on the SS and turrets as well. I've already picked up a waterproof box from the Walmart camping section to use as a radio box.

    I need to order propellers, and I'm looking to stay with scale propellers. So I need props that are 4-blades around 1.5" in diameter. My question is what pitch should I use? Strike is still not taking sales yet, and Battlers Connection offers both 25-pitch and 40-pitch props. Which prop pitch would work best when driven by two 550's? And should I use different pitch props for my free-spinning props (outside props) as opposed to my driven props (inside props)?

    Thanks,

    Carl
     
  6. froggyfrenchman

    froggyfrenchman Well-Known Member

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    Carl
    What 550 motors are you using? The fast 6 volt, or slower 12 volt versions?
    Some folks use the plastic drag props on the non-powered shafts. But if you are going for looks, and plan to use scale props on all four shafts, then you might want to simply use the same size and pitch props so that you have an extra set in case you damage one.
    Mikey
     
  7. dietzer

    dietzer Admiral (Supporter)

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    Hmmm. I don't know. I didn't know there were 2 different kinds. I bought them from a surplus electronics website sevetal years ago, so i don't remember what voltage they are. Guess I'll just have to test them and find out.

    Drag disks are illegal in Battlestations! - we use free-running props instead. And all props have to be the same size.
     
  8. dietzer

    dietzer Admiral (Supporter)

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    OK, my motors are Mabuchi RS-550PF. I found a copy of an old All Electronics sales flyer online that had them listed (All Electronics no longer carries these). No-load ratings are 9000rpm @ 6V, 1.3A. Other stuff I've found online indicates that while Mabuchi claims this motor can run on up to 12V, it will fry very quickly if you approach the stall current at this voltage. So I guess these are what you call the fast 6V motors.

    The Mabuchi spec sheet says this motor at max efficiency draws 14.69 A @ 21840rpm (133.2W @9.072V), and at max output this motor draws 74.75A @ 12000rpm (406.6W at 5.44V).

    75A! 407W! Holy Cow! (Picture Doc Brown yelling "1.21 Gigiwatts" in Back to the Future). I'm definitely putting some fuses inline with these motors!
    BTW, All Electronics still sells the slow 12V version of the RS-550:
    Mabuchi #RS-555PH. 12Vdc (9-20V) motor. Approximately 4500RPM @ 12Vdc, 0.15A (no load rating). 37mm diameter x 58mm long. 3.2mm diameter x 13mm long flatted shaft. Solder-lug terminals.
    So any idea what pitch props will work best with these fast 6V RS-550 motors? And should I consider using a gear drive?

    Carl
     
  9. dietzer

    dietzer Admiral (Supporter)

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    Well, it's been over two weeks since my last update, and I'm way behind on my last goal.
    Being gone for 3 of the last 5 weeks traveling and losing most of two weekends to family stuff has put me behind schedule. I just finishing sheeting the bottom of the hull with 1/32" ply. I've got the stuffing tubes glued in, but I still need to sand, spackle, and sand again the hull so I can fiberglass it. There's less than 3 weeks left until the Sept battle. I haven't given up yet, but things are not looking good.
    My props, silkspan, and some other items came from Battler's Connection a little over a week ago. I have the batteries, charger, 2.4 GHz Tx & RX, ESC and other items on order, but some are coming from over seas, and I 'm not sure when they'll get here. I have a 12oz bottle, but still need to find a regulator (I've tried finding mine in storage, but haven't found it yet). I'm guessing I might have Takao on the water, but un-armed, come battle time.
    Carl
     
  10. Kun2112

    Kun2112 Active Member

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    Carl,
    I can bring a regulator, I picked up a BC one in a Treaty ship trade that I don't think I'll have ready to go back out. I am taking the week before the event off and also am free labor day weekend, so if you need some help in the shop, I could spare a day to help with super structure or internals.
     
  11. dietzer

    dietzer Admiral (Supporter)

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    Thanks, Dustin, I appreciate that!
     
  12. dietzer

    dietzer Admiral (Supporter)

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    Good news! The ESC, battery charger, and TX/RX came today!

    Bad news is I will have to make a gear drive after all. The stuffing tubes came out too close to the keels that form the water channel for a direct drive to work. So I get to make gear boxes.

    Would a single 550 be powerful enough to drive an 84" long boat? I'm debating whether to make one counter-rotating gearbox or two independent gear boxes. All advice is welcome!
     
  13. Kun2112

    Kun2112 Active Member

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    Carl,
    How much clearance do you have to the keel? That will help with suggestions. Pics are also good :)
     
  14. Tugboat

    Tugboat Facilitator RCWC Staff Admiral (Supporter)

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    If you used brushless it'd be plenty and then some.
     
  15. dietzer

    dietzer Admiral (Supporter)

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    Dustin,

    I'll try to upload some pics of this tonight. Basically, I have less than a 1/4" of vertical clearance from the prop shaft to the keels where the shaft exits the stuffing tubes. The stuffing tubes actually come out over the keels, so there's no horizontal clearance I can use to my advantage.

    Unless I severely notch out the keels to mount the motors (compromising the water channeling), I would need to move the 550 motors 9" further forward in the hull for a direct drive to work. Having them this far forward makes them interfere with the rear pair of 4.7" secondary mounts, not to mention the radio box. I could work around the radio box, but not around the positioning of the rear secondaries.
     
  16. DarrenScott

    DarrenScott -->> C T D <<--

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    You could position the motors back over the shafts and use a belt drive. All you'd need to change gearing then would be extra drive pulleys.
     
  17. dietzer

    dietzer Admiral (Supporter)

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    I've thought about using belt pulleys, I just don't have any. I'll have to see what I can find. A belt drive would be easier to setup and adjust than a from-scratch gear drive...
     
  18. dietzer

    dietzer Admiral (Supporter)

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    Well, I wasted a couple of days trying to modify some traxxas gear boxes to make my gear drives, only to have them still end up being too big. :cry:
    Guess it's time to go with a belt drive. I'll have to machine some pulleys -- there's no time to order anything now. Thankfully, I managed to get my sherline lathe out of storage, but I still don't have my dial calipers for precision work. Harbor Freight has some on sale for $12, so I guess that's my best option.

    I want to pour the self-leveling concrete sealer this weekend. Can anyone tell me about how long this takes to cure?
     
  19. Kun2112

    Kun2112 Active Member

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    If you put it on more than 3/8" it can take a week or more. However, Mark discovered that a heat gun can speed the process up dramatically (like, oops it cured before it had a chance to level).
    You might want to consider going with extra long shafts. You can get 1/8" brass in 36" lengths. I used 12" stuffing tubes and 18" shafts in the direct drive system for the Alsace, and will be using 12" stuffing tubes and 14" shafts in the Gus. If you are able to get together for some building this weekend, I can pick some up in Wapakoneta Friday. You have to be a little bit more careful with alignment so not to flex the shafts while turning.
     
  20. dietzer

    dietzer Admiral (Supporter)

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    Woohoo! :)

    Spent a couple of hours going thru the smaller of our three storage units. Found a lot of my modeling tools and materials, including my CO2 regulator! I also found my two 6V 13AH gell cell batteries, my Conway's and my Anatomy of the Ship book on the Takao. I may need to use one of these gell cells (if they're still good) in the Takao if the LiFe batteries I ordered don't get here in time.

    What I did not find yet is my CO2 hose. I may need to buy some from somebody when I get to OH. I don't think I have time to order any at this point.

    Regarding the motors: I already have 24" long drive shafts in the boat. I need them that long so I can mount the motors forward of the aft dual turrets. Any further forward and I run into the space needed for my radio box. Right now I'm having to reserve enough space for a big gell cell battery in case my LiFe's don't get here in time. The LiFe's will fit in the forward part of the hull beside the CO2 tank, but the gell cell won't. :(