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Old Jan 20, 2010, 06:32 PM
Work induced time dilation...
Andrey225's Avatar
Richland WA.
Joined Oct 2008
376 Posts
Build Log
1/400 RMS Queen Mary 2 build

I first built Revell's qm2 model in 2006 but as I was only 12 at the time my modeling skills were not quite up to scratch. Last month (after moving from the UK to America) I decided to try again.
The Revell kit is fairly well made, fits together almost perfectly and (apart from the railings) is detailed enough to avoid the need for severe modification and detailing. Also, apart from a few hull windows the model is very faithful to the original ship.
The only complaints I have about the kit are that the hull windows are not see-through but only engraved into the hull, and the fact that in both of the kits that I've had the staircases at the back of the 7 deck were broken off (and meant that I lost them during the construction of my first model)

Here is a brief summary of the technical details:

Scale;________________1:400

LOA;_________________86.2cm________34"
Beam;________________ 10cm__________4"
Draught;_______________2cm_________3/4"
Height (keel to funnel);__18cm__________7"
Displacement;_________1.18kg_____2lb 10oz

Engines; Two 6mm x 15mm motors in fixed pods, two 6mm x 12mm motors azimuthing.
Combined propulsion power; 6.24Watts (3V, 2 x 610mA + 2 x 430mA)
Bow thrusters; 3 x 7mm props, 2.4Watts combined

Battery: 3.7V 10Ah (37Wh) (planned)

Max speed; Empty: 0.9 knots. At waterline: undetermined (est. 0.7 knots)
360 degree turn time (using bow thruster); undetermined (est. 4min)

(This info will be updated as the build progresses)

The first thing that I had to do was to open all of the portholes in the hull. In order to do this I bought a Dremel 400 XPR and spent a weekend grinding away the 1mm of plastic behind the windows. while it did take a while it now means that I will have far more effective internal lighting in the hull.
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Last edited by Andrey225; Apr 26, 2010 at 11:08 PM. Reason: Info
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Old Jan 20, 2010, 07:38 PM
Grumpa Tom
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United States, CA, Los Angeles
Joined Sep 2003
23,315 Posts
Nice work!
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Old Jan 20, 2010, 09:08 PM
Sea Dragon-Lover
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PDX, OR
Joined Dec 2002
10,284 Posts
I am pretty sure that drum sander didn't make it though all
those small holes. ...
Are you grinding out the back side of the the windows?
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Old Jan 20, 2010, 09:13 PM
Work induced time dilation...
Andrey225's Avatar
Richland WA.
Joined Oct 2008
376 Posts
Yup. The windows are engraved about 1mm deep into the plastic with another 1mm of plastic behind them. I simply ground away that back 1mm and then neatened up the edges of the windows with a small knife.
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Old Jan 21, 2010, 06:55 AM
Registered User
Joined May 2006
290 Posts
nice
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Old Jan 21, 2010, 04:32 PM
Work induced time dilation...
Andrey225's Avatar
Richland WA.
Joined Oct 2008
376 Posts
I've seen a lot of discussion about how to make QM2's drive system and azipods. I experimented with belt drives and bevel gear drives but none of them really worked without severely altering the shape of the pods. It occurred to me, however, that the simplest way to do it is to copy the original. For my first model I used 4mm x 14mm diameter pager motors inside each of the pods, while they worked well in the air, however, they had barely enough torque to turn underwater and the ship could only crawl slowly through the water. Also as they barely turned they also tended to jam and break.
This time I decided to use 6mm x 12mm pager motors from Didel. They work far better but will not fit into the pod without a lot of cutting and scraping (until the sides were so thin that i could see through them).
The motor shaft was also too short to mount the prop, but thankfully I found some metal tubing which fits perfectly around the shaft and voila! an extension.
The only concern I have now is that I might inadvertently break the tiny plastic props. I'll have to be a bit more careful with the throttle this time...
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Old Jan 22, 2010, 11:57 AM
Sea Dragon-Lover
Umi_Ryuzuki's Avatar
PDX, OR
Joined Dec 2002
10,284 Posts
Nice!

Any water penetration into the pod?

.
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Old Jan 22, 2010, 12:41 PM
Grumpa Tom
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United States, CA, Los Angeles
Joined Sep 2003
23,315 Posts
That's pretty amazing. I never knew motors were so tiny. 4 and 6 mm? Wow!
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Old Jan 22, 2010, 01:24 PM
Work induced time dilation...
Andrey225's Avatar
Richland WA.
Joined Oct 2008
376 Posts
I was pretty amazed about the motors too. They are mainly used for micro RC planes but I dont see why I cant use them for boats too. As for leakage I have had one 4mm motor break due to that, however I've made sure that the 6mm motors are sealed on the outside and the propshaft is also greased to stop water entering the pod. Even if it does leak the pod is islotaed from the rest of the ship so it can not leak into the hull. I'm still hoping that I won't have to cut any pods open to replace motors...
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Old Jan 22, 2010, 09:19 PM
Work induced time dilation...
Andrey225's Avatar
Richland WA.
Joined Oct 2008
376 Posts
Started work on attaching the pods to the hull. I'm using some bearings from VXB ball bearings who actually sell small enough bearings for the pods (5mm inner x 2.5mm wide). To get full 360 (or really only 180) degree turning for the pods I'm using a geared steering system (using some gears I found in a VCR which someone threw away recycle!).
Perhaps at this point I should explain that i am not planning to use any conventional remote control systems. Instead I have decided to use PIC micro-controllers (or about 7 of them) to control and automate all of the ship's hardware and lighting systems. Then, using a digital radio link I will be able to send instructions (or direct commands) to the ship from a separate board of switches or maybe even a computer (when I learn enough programming... hopefully...) This method has been used a lot by people working with remote controlled robots, and although I've never worked with robotics, I don't see why I cant do a similar thing for a ship.
I am, however, treading mostly into uncharted territory and I doubt that it will be a smooth build. I may resort to a conventional RC system if all else fails. As the wise man said "hope for the best and prepare for the worst"
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Old Jan 23, 2010, 09:03 AM
Registered User
United States, TX, La Porte
Joined Apr 2007
1,668 Posts
Clever, very clever, I hate that!!!:-). Last Christmas I almost bought the kit as it was on sale for very cheap but I passed because of the pods. Just goes to show that there is always someone with a great idea.
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Old Jan 23, 2010, 11:56 AM
Work induced time dilation...
Andrey225's Avatar
Richland WA.
Joined Oct 2008
376 Posts
Hi Gravman,
I have to say that when I first bought the kit I had no idea how to motorize it at all. after about 2 months of thought and experiment I almost gave up altogether and opted for a shaft driven system. Unfortunately my infallible perfectionism prevented me from ever actually doing that so I just left it alone. I stumbled across the pager motors completely by accident and even when I got them I broke two during installation and another two later on. The system was also very weak and slow so I could not sail outside my bathtub. I'm hoping that the new motors will have enough power to move it but this will still be an indoor sailing model.
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Old Jan 23, 2010, 12:35 PM
Sea Dragon-Lover
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PDX, OR
Joined Dec 2002
10,284 Posts
It would still be neat to see this out at Bellevue Park at one of the Regatta.
Or maybe Spokane during the tug boat meet in July...



We want to build some boats to sail in Hood River, but those will be
some rough water, self righting models... definitely not a place for
small scale...
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Old Jan 23, 2010, 12:45 PM
Work induced time dilation...
Andrey225's Avatar
Richland WA.
Joined Oct 2008
376 Posts
Well... with 4mm motors the QM2 could reach about 0.15 knots indoors, with the 6mm ones I might get it to over 1 knot but I really don't have a clue how fast it will go. All of the pods should be finished by the end of today and then I'll try to find out...
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Old Jan 23, 2010, 03:50 PM
Work induced time dilation...
Andrey225's Avatar
Richland WA.
Joined Oct 2008
376 Posts
Engine test complete!

I am very impressed by the acceleration that I get from these motors! I have no idea how fast it can actually go because it only gets about 50cm of room in the bath. Also as the hull is still in two halves, and held together with tape and rubber bands I only got about 20 seconds before it started flooding (so not really much of a float test! ) However, in calm weather, I may be able to sail it outdoors as well.

I have uploaded a video at http://www.rcgroups.com/forums/showthread.php?t=1180889
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