Want to build a Revell kit and make it RC - Need help.

[tugboater]

Hello. I want to start a new project that has been done on this forum before. I am thinking about buying Revell's Queen Mary 2 model and making it an RC. I have no knowledge on building RC's, so I need some help on what I need to buy. Based on what the previous builder did, I know I need different props. I know I want it to go a scale speed of 22 knots so it is like the real ship. If anyone can help me out, please do, as I need all the help I can get.

Thanks,
Ryan
"tugboater"

[Roger in France]

I also have the "QM2". Our local hypermarket had them for a very short time at 30 Euros by Heller. I bought it on impulse and have now sat back to ponder. The props. are far too small to motorise and so it will need a "false prop." some where to move it along. Also, all those portholes will need careful sealing to ensure water tight integrity.

Having said all that, it should look very smart sailing across my swimming pool.

But building it is not my highest priority, there are three more for the buiding slip before it!

Roger in France

[tugboater]

Thanks Roger. I did notice that, and when I build it I am probably going to get some a bigger prop that will be used for moving the ship.

[patmat2350]

The real QM2, and your model, have two fixed and two azimuthing thruster pods. Unless you have micro (or nano!) machining capability, you'll need to give these up and be happy with 2 or 4 (I suggest 2) standard prop shafts and props.
For props, you can get about 3/4" (20mm?) brass 3 or 4 bladed props with either a small metric, or preferably in the US, a 1/8" thread (#5 thread, can be die cut directly onto 1/8" shafting). Contact Don at www.loyalhannadockyard.com , he has the stuff.
Suitable brass tube can be used to make the stuffing tubes; fitting and sealing these to the hull is your task, but they need to be adequately braced to prevent waggling. If you don't want to make external braces, you'll need a stout tube to cantilever the prop out far enough.
With these small props, direct drive motors should work just fine, but you'll need to couple them to the shafts with flex couplings... a whole 'nother discussion.
Get that far, decide where to hang a rudder (none on the real ship), and figure out how to make the deck detachable, then the r/c part is easy. Call back when ready!
Pat M

[mfr02]

The biggest problem with liners at this scale is getting them to stay upright. The upper decks are usually one sheet of plastic per deck, and the superstructure will need a great deal of hollowing out to stop the model being top-heavy. You then need to look closely at how much hardware the hull will carry and still float at waterline.
Best of luck with it.
MalcolmF

[tugboater]

Thank you both for your input. Pat, I did not understand much of what you were saying. I am a novice at building and don't know what everything is or does.

[towboatjoe]

There may not be much of a problem with the vessel being top heavy due to the ballasting it'll take to put the hull at waterline. I have a how-to page at making your own simple shafts and props that would work for powering plastic models at http://www.towboatjoe.com/shafts.htm

A tip for connecting the shaft to the motor is to use a piece of surgical tubing. I've used this trick to power a boat 7 inches long. I've also used it on a 25 inch model.

[Umi_Ryuzuki]

We know that converting the QM2 can be done.
Assembling the boat is actually the simple part.

What Pat is recommending are stuffing tubes. These are grease filled tubes that pass from the inside of the boat to the outside. They are cemented into place through the hull and allow the propeller shafts to run from the motor to the propeller without letting water back into the boat.

These stuffing tubes can be bought, or made from scratch.
http://www.rcgroups.com/forums/showthread.php?t=437771

Once the hull is assembled, you can place your stuffing tube/tubes into the boat at the angle that will allow the propeller to spin beneath the boat, and the other end of the shaft to reach the motor shaft.

If you look at Tony's North Sea Trawler conversion, or maybe Pat Tritles Baharain conversionn you should be able to see how few parts are really necessary to make a plastic model run.

Transmitter/reciever
Battery
Electronic Speed Control(ESC)
Motor, Propeller shaft, stuffing tube, propeller
Rudder, and Servo, (an old control linkage diagram) (http://www.rcgroups.com/forums/attachment.php?attachmentid=220991)

[tugboater]

What size motors would I need to make it stay slow but powerful? What propeller size do I need to keep it to scale, or at least close? Thanks so much for all the help. It is much appriciated.

[tugboater]

Also, would I build the complete model and then turn it into an RC, or would I put in the gear then build it? How could I light it up? I'm asking questions before I waste time and money. Thanks in advance.

[patmat2350]

Tugboater-
Converting plastic models to r/c can be fun, but with the amount of custom work involved, it might not be a beginner's project. You can learn here (we've been there, sank that!) and give it a try, but you might be even better off with a model designed for r/c that includes complete instructions on the running gear and electronics.
A couple options to get in slowly-
a) Get a RTR boat, like the Atlantic Tug. Everything's there already, and it's easy to work on. You can rip it apart, put it back together, and/or customize it bit by bit, learning all the way. And for the price, wow! You'll spend that much r/c'ing your plastic model.
b) Get a good complete r/c kit. You may like the idea of plastic kits, 'cause you can just glue the parts together... I wish more good r/c boats were like that! But maybe something in Midwest's 'Success Series' (http://midwestproducts.com/RC%20boat%20models.htm) is a low risk kit to try? Not sure how complete their mechanical and r/c instructions are though ("left to the modeler" is heard all too often).
c) Pick up a book, like Tom Gormans' Model Merchantmen (http://www.amazon.com/gp/product/1557509093/sr=8-3/qid=1140487831/ref=sr_1_3/103-7676764-9971841?%5Fencoding=UTF8) (it's really a good all around model boat book, with props and motors and r/c and hull construction etc), and read for yourself.

Pat M

[tugboater]

I already have the Atlantic Model. I want to do the Queen Mary II because I love cruiseliners and it seems to be the only model cruiseliner on the market.