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Old Jan 02, 2005, 08:33 PM
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Joined Jan 2005
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Question
Queen Mary 2 1:400 scale R/C conversion

Hi guys new member here looking for some advice on how to convert this kit into R/C.

I'm very base level at this sort of stuff so please excuse the apparant ignorance. i was hoping to run this baby on a differential thrust basis rather than with a rudder - would this be advisable?

If so would the complete set up for this type of thrust which i took out of my crashed stealth bomber R/C (only a cheap toy kit) be suitable? i don't know what the power values of the two motors are but they were able to power the plane ok.

the QM2 kit is 850mm in length and will be quite lumpy when finished.

http://www.revell.de/typo3/en/produc...ndex.html?&L=1

Any tips whatsoever would be hugely appreciated, but please remember i don't have 100's and 100's of pounds to spend on this so i'm looking for a basic solution.

Thanks again

Steve, Plymouth UK
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Old Jan 02, 2005, 08:46 PM
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Umi_Ryuzuki's Avatar
PDX, OR
Joined Dec 2002
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TonyO's thread on converting the Revell "North Sea Trawler" should give you some good ideas.

http://www.rcgroups.com/forums/showt...hlight=trawler



Oh yeah, "Patmat" also just posted this the other day. His LCM.
http://www.geocities.com/patsmodels/lcm3/

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Old Jan 02, 2005, 09:19 PM
Veni, Vidi, Feci
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Joined Dec 2004
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Qm2

By "differential thrust", do you mean thrust vectoring, which 2 of the 4 pods on the QM2 can do?

If the pods are to be kept, instead of using standard prop shafts, I've been thinking that the answer lies in dental prophy tools, see picture. Not sure how to adapt them, but these little right-angle heads should be able to mount some small props. Not a beginner's project!
Vectoring of the units should be possible too, but it will take some fancy micro-work.
Next question- does she have a chance of floating upright? This model will displace only about 2.7 lbs [1.2 kg], and she'll be top heavy. The kit should be rough-assembled and float tested before investing too much in an r/c conversion. Perhaps if you let the waterline rise a bit, stability will be improved.
Good luck, and post pix if you get started!
Pat M
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Old Jan 03, 2005, 04:46 AM
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thanks guys for the advice, I'm not sure if the term differential thrust is the correct one to use but what i mean by it is, using port and starboard propulsion as a means of steering (like cheap to R/C planes do).
I'm probably just going to use standard prop shafts etc as trying to recreate the QM2's pods will be way above me. but the dental tool idea looks very interesting!
I must admit i'm a bit worried about the stabillity issue now, i thought it would be a simple case of finding the correct ballast level

I'll just have to look deeper for the answer.
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Old Jan 07, 2005, 05:18 PM
no wings any more, just dust!
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stoke on trent
Joined Oct 2004
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you can buy azimuthing thrusters from graupner i think, and they should go straight in, steered by a servo, with a bevel drive off the motor. as regards ballast, lead weights that STICK onto alloy wheels are best, I have a graupner neptune which i have named "Gemini" and added lights to it, (see the my galler, that is a similar length and requires 1.2kgs of lead. to do it correctly, you will need 4 motors, and a 4 channel FM radio set, 4 speed controllers as well.

it could be done with two speed controllers, one for the front set and one for the rear set, just keep the ballast low in the hull. there is no reason why it could not be done.
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Old Jan 07, 2005, 05:45 PM
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Cheers ghost
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Old Jan 08, 2005, 08:35 AM
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I'd say it's an ideal conversion apart from the one item you picked out - there's a lot of 'top hamper' so as much of the weight (batteries and motor) as possible should be as low as you can get it and mounted on the centreline. You can always remove some of the plastic of the decking you can't see to get the centre of gravity lower, but you probably will not need to.

It's quite a big model in contrast to the trawler Umi directed you to. That was an aeromodeller's approach for simple and inexpensive boating.

The radio and speed controller weight is relatively low. I think you'll be surprised how much ballast it will take to get it down to the correct waterline. There's ample space for a steering servo - one of the ultra-small cheapo ones will do the job.

A little bit of modeller ingenuity will see you though, and post back if you have any problems or want suggestions. It looks a goer to me!

Tony
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Old Jan 08, 2005, 09:09 PM
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Cheers tonyo, i've rough built the hull now and float tested her, you're right about the amount of ballast, it took loads, but i've gother floating very steadily now(obviously without most of the superstructure as yet) if the worst comes to worst i'll use a cheat keel or some sort of stabilisers, this'll be a last resort though!
I've ordered all the electronics, i've gone for twin motors and i'm going to retro fit standard shafts(the pod system was just to advanced for me), and im going to stick a rudder on her as well to ensure manoeuverability. I should be ready to get her guts built and tested at the local lake pretty soon, keep your fingers crossed.

I'll post some pics when i get to that point.

One question, after i've installed all the usefull weight of battery etc i'm still gonna need quite a lot of extra weight, i was thinking of using fishing weights, what do ya reckon? any other suggestions?
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Old Jan 08, 2005, 10:01 PM
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Lead is nature's best ballast! Shouldn't be hard to accummulate enough (whilst riding his bicycle around, my brother was able to pick up enough cast-off tire weights to ballast a 2 meter sailboat!). And if my physics are right, you'll total 1.2 kg, not so much... but more if you settle her down a bit lower.
I have an r/c Lindberg Fletcher... long & skinny, about 1.5 kg. Stable enough at scale speeds, but try to run her like a toy speed boat, and she'll just about go round-side up! Scale bilge keels & such don't seem to have much effect.
Assuming you have a rechargeable pack, try installing a charge jack... it's usually tedious to open up a model like this, so a jack can save a lot of effort. But if you can engineer a bonnet that just pops open, great! Picture shows a jack hidden under the torp tubes on my Fletcher. The 2nd set of tubes rotates a cam to engage a reed power switch.
Pat M
http://www.geocities.com/y2patmat/
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Old Jan 08, 2005, 11:23 PM
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Hi stevedurrant,

I hope I am not too late to chime in here.

Have you looked at Goupner's Shrouded prop propulsion and steering gear SPPS (Groupner Part #1775)


and Groupner's Side thruster with electric motor (Groupner Part #1785)?


I think you may find them useful for your ship. Good luck and hope to see your finished build!
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Old Jan 09, 2005, 05:52 AM
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Athens/Greece
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nice snuffleupagus...but they are propably too big for the model!!!
they will be out of scale!!
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Old Jan 09, 2005, 08:14 AM
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Steve - not easily available, but lead shot is the easiest thing I've found. I pour it into poly food bags in the appropriate place in the boat and it finds its own level. When you're sure of the amount, pour into each bag a little coating resin - enough to wet the shot and squidge it around until all bits are coated then put it back in the boat. When it's solid, you've a conformal lump of lead in polythene. It's usually removable too.

Pat M - I built the Fletcher too - there are some pics around on this forum and in the Gallery but I can't post a link as search is disabled as I write this. I thought it an awful kit and it needed a lot of work to bring it up to a reasonable model. I made the whole deck and superstructure removable except for the last bit at the stern where the lower gun is, and the extreme front of the bow deck. It looks good at a distance. Lots of extra 'bits' and a crew of about 20 make it look busy and not so plasticky, but it needs calm weather to sail it as there's little freeboard at the stern.

Tony
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Last edited by tonyo; Jan 09, 2005 at 08:15 AM. Reason: tidy up
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Old Jan 09, 2005, 08:46 AM
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Oh yes it's an awful kit... but it can be dressed up. See the next thread!
Pat M
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Old Jan 09, 2005, 11:23 AM
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Quote:
Originally Posted by loon1x
nice snuffleupagus...but they are propably too big for the model!!!
they will be out of scale!!
That's ok. They should still do the trick. Besides, once that boat is in the water, people are not gonna notice or care that it's not scale.

They will all be too busy admiring how agile and mobile the boat is!
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Old Jan 09, 2005, 04:26 PM
no wings any more, just dust!
Ghost 2501's Avatar
stoke on trent
Joined Oct 2004
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those graupner azimuthing thruster units may not be too out of scale, at the end of the day, the props are 40mm in diameter, the prop on my neptune is somewhere around 30mm, so that wont be a problem, and like snuffle said, below the waterline when on the water, scale does not matter.
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