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Post by valleydweller on Jul 16, 2007 16:51:38 GMT 1
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Post by markus on Jul 16, 2007 17:10:49 GMT 1
Hi Markus, If I look back along the pre-formed prop-shaft holes in ribs 13A and 39A (or slide the outer prop-shafts in place), they appear to be centred on a point which is about approximately 5mm below the motor axis. Should I trust the Hachette prop-shaft positions/angles? that's right, these holes are in right position if the shaft is mounted 100% horizontal like in poster from hachette's static model. this is nonsense, the original shafts had 1-2 degrees angle. posted the link concerning the original layout earlier in this thread. so these holes can only be used to find the right position for the shaft's hole in the hull. this is done by gluing a 3mm drill into a 4/3,1mm brass tube. this 'drill' guided by these holes is a proper tool to find the right postion for the shaft hole in the hull markus
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Post by bob on Jul 16, 2007 17:13:21 GMT 1
Nice pictures. besides making the cut outs for the motors, you may need to slightly enlarge the holes for the side props. I bought my three motors, propshafts and propellers from Marcus plus motor bracket ready built for 90 Euro. Money well spent arrived within a week of ordering. He has a price list in an earlier post. Plus somewhere he has posted instructions for Part D drilling. Which worked fine for me.
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Post by markus on Jul 16, 2007 17:33:57 GMT 1
Thanks Bob Now all I have to do is start grovelling to the wife to explain the "need" to order them from Markus In addition to the motor set (remember I am a complete newbie to R/C) what exactly do I need? I know that a lot of info has already been given but its all greek to me Dean hi dean! first of all: good work, middle shaft shall fit without problems !! found a piece of wood which has to be removed: will send you a pm soon with 4 different sets to motorize your bismarck. (different sets with/without mixer and with/without radio control) markus
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Post by markus on Jul 16, 2007 18:07:06 GMT 1
some folks were concerned about putting too much weight into the hull using those 9000mAh cells. i tested with 3motors, 6 cells, complete rc and partly superstructure and had to add another 2 kilos of ballast to give a good draft for those who are still concerned and don't care about running times of approx. 30min. with 2 motors (or 20min. with 3 motors) here's a possible solution: high current cells 4000mAh, price is 10 euro each 5 of these cells (6V 4000mAh)offer the double running time than a 6V 4500mAh lead acid battery.
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Post by bob on Jul 16, 2007 18:38:52 GMT 1
Good info on the batteries Markus. What about two sets in parallel, giving a theoretical 6V, 8000 mAh. Would they run for 40 mins with 3 motors? Did you measure current drawn , I am assuming your caculations are based on full load per motor of 3.3A.
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Post by markus on Jul 16, 2007 19:24:09 GMT 1
Good info on the batteries Markus. What about two sets in parallel, giving a theoretical 6V, 8000 mAh. Would they run for 40 mins with 3 motors? Did you measure current drawn , I am assuming your caculations are based on full load per motor of 3.3A. yes, theoretical 8000mAh and 40 mins running time with the same weight as the 9000mAh cells....but: you can't charge both sets to 100% if they are connected to each other, you may overcharge one of the sets. especially if you use a intelligent charger which recognizes a rising current drain (when battery is fully charged). used 2 sets of these cells ( 2 sets of 8 cells connected together)in my first titanic. charging with an intelligent charger almost resulted in a burning ship. luckily i was at home while charging '..hey, what's that smell...?' ___________________________________________________ i measured the current drain with fully loaded 7,2V battery and nylon props in my bathtub. current drain was approx.12A for 3 motors (4A each)with nylon props current with lassek props is 11A (3,7A each) i was deeply impressed by the enormous thrust of this drive, especially when using the nylon props the only mistake was to fill the bathtub almost to the max. before testing..... ;D ;D ;D ;D powering with 6V instead of 7,2V gives a current drain of approx. 3,3A (nylon) or 3A (lassek) this is more than enough to power the ship, even with only 2 motors running times are calculated with a steady current drain of 4A. you won't sail the ship all the time at full load, but receiver and servo(s) also need some power. also speeding the motors up will cause a much higher current for a short moment this calculation if of course not exact, but as close to reality as possible with 6V running time is longer due to less current drain markus
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Post by bob on Jul 16, 2007 21:19:51 GMT 1
Thats very useful thanks Marcus. My intention was two 4000mAh packs at 6V. I was also intending to charge them seperately. I am guessing approx 40 mins running time. Point taken about Servo current drain and RX drain. Usually a Rx draws approx 150mA dont know about servo will have to look into that.
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Post by swanrail on Jul 16, 2007 22:33:50 GMT 1
Hi Valleydweller, in addition to the cut outs that you show on your picture, also note a further cut-out is needed to fit the rudder servo if you follow Markus lead (see his pic ref the extra cutout). My rounded cut outs for the motors were done using a Black and Decker power file, which having a rounded end, makes short work of producing the required shape. I also used it to remove the excess keel that Markus mentions in order that the motor housing will go in correctly. Although a bit of a heavyweight for modelling, the power file is very handy for modelling and responds well to a light touch.....a heavy one will eat the complete ship in no time!!!!
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Post by swanrail on Jul 16, 2007 22:41:54 GMT 1
My 8kg British Chancellor (single prop) uses a 1200maH Nicad 7.5volt battery which lasts over 35 minutes. I think that Markus has hit the nail on the head, at something like 3 A per motor, he found a tremendous amount of power. The model will act like a speedboat and not all realistic. I had great trouble managing to throttle my model back so that it looked good, this should reduce the running current quite a lot. As this is my first attempt at triple screws and lead acid, when I can get her afloat will do some trials, but ideally in something bigger than a bath in order to assess the running speed correctly.
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Post by eric on Jul 16, 2007 22:55:31 GMT 1
Markus, are you still selling your two motor offer? I am very tempted, but have NEVER worked with R/C before and don't know the first thing about it, but am really keen to give it a go.
How much is it, and what else do I need to buy.
Sorry if you get asked this all the time.
Thanks eric
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Post by markus on Jul 24, 2007 9:51:16 GMT 1
the specs of those 4000mAh cells have changed now they have 4500mAh instead of 4000mAh, price remains the same markus
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Post by valleydweller on Jul 31, 2007 20:38:52 GMT 1
Hi Markus, Just another question on the Radio Controller: I take it if I want to make the turrets operational I will need a 4 channel, is this correct? Thanks bud Dean
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Post by markus on Aug 1, 2007 17:20:53 GMT 1
Hi Markus, Just another question on the Radio Controller: I take it if I want to make the turrets operational I will need a 4 channel, is this correct? Thanks bud Dean only if you want to make the front and rear turrets independent from each other - if you want to turn all turrets together 3ch will also do markus
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Post by valleydweller on Aug 2, 2007 3:50:04 GMT 1
Thanks Markus, I was at the only model shop I could find in N.Ireland recently and they were selling a 4 channel for £50 but it was all controlled by the 2 joysticks, I asked if there was a 3 channel but they looked at me like I was an idiot so I assumed that you could only get 2 or 4 channel controllers.
Dean
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