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Author Topic: Miniature right angle drive  (Read 7671 times)

Colin Bishop

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Miniature right angle drive
« on: March 05, 2007, 07:31:25 PM »

A while back I bought the Revell Queen Mary 2 kit with the idea of converting it to RC. It would be nice to be able to simulate the pod thruster drive but this would entail a vertical shaft in the hull and a horizontal shaft in the pod probably using bevel gears - a bit like an outboard motor. Has anyone any practical ideas as to how this might be done? My thoughts were to have a tube in a sleeve going through the hull with the pod on the lower end to make it steerable - like a conventional rudder but greater diameter. The drive shaft would then go down the centre of the inner tube with maybe a pulley drive on the top connected to a small motor. The whole thing would depend on a right angle drive mechanism in the pod though.
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Eddy Matthews

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Re: Miniature right angle drive
« Reply #1 on: March 05, 2007, 07:41:11 PM »

This might be too large, but take a look at the MFA/Como website, they do a bevel gearbox.... You'll find it near the bottom of the pdf file in the link below.

http://www.mfacomodrills.com/pdfs/gearbox_colour_brochure_12-19.pdf

Regards
Eddy
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Colin Bishop

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Re: Miniature right angle drive
« Reply #2 on: March 05, 2007, 07:54:12 PM »

Thanks Eddy,

As you say it may be a bit big but I will check it out anyway. It's certainly the sort of thing I had in mind.

Colin
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johno 52-11

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Re: Miniature right angle drive
« Reply #3 on: March 05, 2007, 07:56:45 PM »

I have built my own model outboards you can see them here http://www.lifeboatmodels.co.uk/atlantic.htm I can give you more details if you want.

Regards

John
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Colin Bishop

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Re: Miniature right angle drive
« Reply #4 on: March 05, 2007, 08:18:51 PM »

Superb pictures John, the finished model looks great. Really catches the essence of the prototype.

How did you actually make the gearbox though? The pics just show the two shafts disappearing into an apparently solid block!

The latest Hobbies catalogue doesn't seem to feature the model outboards although I remember that the earlier ones did.

Thanks,

Colin
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gingyer

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Re: Miniature right angle drive
« Reply #5 on: March 05, 2007, 10:48:21 PM »

hi
there you can buy the bevel gears and bit
like that from maplin's and then you can make
your own gearbox

http://www.maplin.co.uk/Search.aspx?criteria=gears&source=15&SD=Y

if you look they have a right angle gear box

Colin
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HS93 (RIP)

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Re: Miniature right angle drive
« Reply #6 on: March 05, 2007, 10:54:02 PM »

Instead of using right hand drives, How about putting the motors in the pods??   Peter



http://www.precisionmicrodrives.com/index.php?catTop=1?osCsid=c1848fedbcc9a4e2a320bd341473f40a
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johno 52-11

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Re: Miniature right angle drive
« Reply #7 on: March 05, 2007, 11:48:02 PM »

Superb pictures John, the finished model looks great. Really catches the essence of the prototype.

How did you actually make the gearbox though? The pics just show the two shafts disappearing into an apparently solid block!

The latest Hobbies catalogue doesn't seem to feature the model outboards although I remember that the earlier ones did.

Thanks,

Colin

Colin

The block has two holes drilled in it the horizontal hole has a smaller hole at the end with a bearing in it and a plug with a bearing to hold the shaft in place. The plug is threaded and has a 10BA pin in the side to stop it coming un screwed. Once this shaft is in place the vertical shaft is then screwed in from the top until the gears mesh and that is fixed again with a 10 BA pin. once all this was done the block was shaped by hand. All the parts where turned on a lathe the main block was done in a 4 jaw chuck. You do need a Farley accurate machine. I did all my work on a 1948 Southbend which is very similar in size to the Boxford lathes. I may be possible to do it on a smaller mini or micro lathe if you have access to one but I have allways found the bigger machines much more versatile.

Hope this helps

John
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Colin Bishop

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Re: Miniature right angle drive
« Reply #8 on: March 06, 2007, 01:11:03 PM »

Thanks for all the suggestions eveyone. The pod mouldings supplied in the kit are only 2.5cm long by 2cm high and about 5mm thick which doesn't leave much room for a set of bevel gears and associated shafts and bearings. Looks like I might have to settle for conventional twin screw drive. I did pick up a couple of small bevel gears when I was browsing in Squires the other day (an expensive practice!) so I might experiment to see how small I could make something.

The idea of just mounting little motors underneath is an attractive one but how could you be sure of sealing the output shaft satisfactorily?
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HS93 (RIP)

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Re: Miniature right angle drive
« Reply #9 on: March 06, 2007, 01:20:35 PM »

One other method may be to use thin piano wire  to the pods , they would be hard to spot  but the pods would not rotate very far.Peter
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Colin Bishop

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Re: Miniature right angle drive
« Reply #10 on: March 06, 2007, 01:43:46 PM »

All the builds I've found on the Net seem to go down the twin screw route. One of them minimises the unscale effect to some extent by having the shaft terminate in front of one of the pods where the prop would usually be and leaving the pods in place.
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anmo

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Re: Miniature right angle drive
« Reply #11 on: March 06, 2007, 01:54:35 PM »

A guy I know is currently motorising the same kit. He told me he was going to try waterjet propulsion, with the outlets in the pods. We all tried to think of reasons this wouldn't work, but couldn't really come up with anything. Next time I see him, I'll ask about progress.
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HS93 (RIP)

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Re: Miniature right angle drive
« Reply #12 on: March 06, 2007, 02:15:56 PM »

Yes the idea is to go through the pod with the wire so the only non scale bits the piano wire from the hull to the pod as a drive shaftyou would get away with very fine  piano wire and you would be able to have the prop at the correct angle. Peter
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Colin Bishop

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Re: Miniature right angle drive
« Reply #13 on: March 10, 2007, 06:25:52 PM »

I may have found something in a toyshop in Littlehampton (no Sid James jokes please!). The pictures tell the story. The gears and shafts appear to be nylon. The lower leg of the outboard is a bit oversize but not excessively so. I don't suppose you can put too much power through the thing but it might be enough. Worth playing around with anyway as the boats were only 2.49 each.
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Subculture

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Re: Miniature right angle drive
« Reply #14 on: March 13, 2007, 07:48:59 PM »

If that doesn't work out, and you can live without a prop, how about using a jet.

You can use a centrifugal pump (a small 'Reich' pump would be ideal) and connect it to a steerable swan neck via some silicone tubing.

Would make a very powerful thruster.

Andy

Colin Bishop

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Re: Miniature right angle drive
« Reply #15 on: March 13, 2007, 08:00:25 PM »

Yes, that is another option, Particularly useful for simulating a bow thruster too!
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vosper

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Re: Miniature right angle drive
« Reply #16 on: March 13, 2007, 11:03:05 PM »

 :HI
I have seen small motors from mobile phones used to motorise 1/72 spitfire kits,
I can not remember if they have enough torque, but with 4 running it may work, that is what i thought to do then it would be scale like, mounted like full size.
Hope it may be of help
Vosper
Huw
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Colin Bishop

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Re: Miniature right angle drive
« Reply #17 on: March 22, 2007, 05:17:01 PM »

I've been playing about with the miniature outboards. First I cut off the top and removed the friction motor. This left just the outboard leg which is of plastic and contains a couple of nylon shafts with bevel gears. I then found three diameters of brass tube from my bits box. The smallest one is glued over the vertical stub to extend the drive shaft. The next size up goes over this and is fixed into the top of the leg assembly to constitute a "rudder" shaft. The last one acts as a rudder tube secured to the hull. The idea is to use the middle tube to steer the pod and the inner one will be connected by a horizontal pulley drive to a vertically mounted 3-6v motor. I think it will all fit. The big question is whether the bevel gears will be up to the job. There won't be much power going thrtough the assembly so I might be lucky. Worth a try anyway.

The "pod" is a bit oversize but, as you will see from the picture, it does look the part.
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Colin Bishop

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Re: Miniature right angle drive
« Reply #18 on: March 24, 2007, 06:37:44 PM »

Having stuck the hull together I want to test whether the units will give sufficient drive which means making it watertight. I suspect I will need some sort of bow thruster arrangement and using waterjets seems the most obvious choice. For this I need a small reversible pump. Normal car windscreen pumps are 12v and I really want something that will run on 6v or under. Anyone got any ideas? I seem to remember a mention of one a little while back but I can't find it using the search facility.
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catengineman

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Re: Miniature right angle drive
« Reply #19 on: March 24, 2007, 07:59:32 PM »

I will need some sort of bow thruster arrangement and using waterjets seems the most obvious choice. For this I need a small reversible pump. Normal car windscreen pumps are 12v and I really want something that will run on 6v or under.


Hi just a thought that you could use a screen washer pump from a Renault (one direction will deliver to one pipe the other to a different pipe and the pump inlet is the same.. IE: three pipes to the pump) I have one in my Tito Neri As the ESC cooling pump or the fire monitor system.
at 6 volt it will run and the thrust is possibly just enough for your needs (I have had to restrict the flows from the pump running on its nominal 12 volts to get a realistic O/B rate)

Richard,
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rats

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Re: Miniature right angle drive
« Reply #20 on: March 24, 2007, 08:49:58 PM »

Colin - Hunter systems do 6v submersible pump that may be what you were looking for

         http://www.huntersystems.co.uk/
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Colin Bishop

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Re: Miniature right angle drive
« Reply #21 on: March 24, 2007, 09:50:18 PM »

Thanks for the responses folks. Yes, it was the Hunter unit I was thinking of. I'll have to check if it will fit.
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Colin Bishop

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Re: Miniature right angle drive
« Reply #22 on: March 25, 2007, 08:37:33 PM »

I've ordered the Hunter pump. Now I'm looking for a couple of cheap, lightweight ESCs which will handle 6v input. All the adverts seem to stress muscle bound ones which will handle umpteen amps. I just need lightweight ones that don't cost too much!
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DickyD

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Re: Miniature right angle drive
« Reply #23 on: March 25, 2007, 08:49:36 PM »

Deans Marine  :  MARINE. 1    6 volts / 1amp   

 wt 15gms    29mm x 34mm x 5mm

  This unit has been designed to Deans Marine Specifications for use in the COMPACT kits and the smaller lighter models in the range.

 This miniature unit weight only 15gms and gives full proportional speed control in forward and reverse  The unit is designed to run on the BEC system in

that the power for the R/X  AND THE DRIVE MOTOR is taken from the  R/X power supply . This unit is waterproof and features one touch set-up, and is

prewired with a plug. 17.75

Richard ;)

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John W E

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Re: Miniature right angle drive
« Reply #24 on: March 25, 2007, 09:03:38 PM »

Hi Colin, have you thought about the mini-ACTion esc's the micro ones - I used one on my last build - the kit costs about a tenner plus postage - ready assembled I think are about 13 the only drawback is they use the power supply from your TX to drive them.  They can only handle max of 1amp. (have a look at the topic the year I was born 105 make that 1955  ;D )

aye
john e
bluebird
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