Model Boat Mayhem
Mess Deck: General Section => Model Boating => Topic started by: ubernuka on May 20, 2009, 03:25:57 pm
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i newbie
can anyone help me?????????
is there a model gearbox suitable for a 7.5cc glow engine with a selectable reverse gear? :o
big ask methink. hopes not .
is this even possible would it need a centrifugal clutch and a three channel radio could it run two props ,so many questions so crap at typing
any help on this really appreciated as its the only thing stopping me from buying an engine instead of motors.cos you cant have something fast with no brakes (fun but not for long) :D
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It's been asked many times before, don't bother.
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waaahhhh
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{-)
Why would you want to go backwards anyway?
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Google Kitchen Rudders
Regards,
Gerald.
(http://www.postimage.org/aV2n4K0.jpg) (http://www.postimage.org/image.php?v=aV2n4K0)
(http://www.postimage.org/gx11l8wr.jpg) (http://www.postimage.org/image.php?v=gx11l8wr)
(http://www.postimage.org/gx11lb0A.jpg) (http://www.postimage.org/)
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You can get electric to run fast, and go backwards, much easier.
Boat in pic is 1 mtr long,and as you can see going like the clappers :-))
As Andy says backwards glows----hummmmmmmm
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Thats the one with Mark's motor is it Phil? Letshaveago! O0
I still don't see why anyone would even want the ability to make an IC boats go backwards. I built my latest multi to go fast in a straight line and corner without loosing any speed, as it should do. It does, very well. I did not however make it to parallell park...
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Almost anything can be achieved if you have the time, resources and money to throw at it.
Without any one of those three, it could become a difficult proposition.
Based on full time costs, a designer will charge you a few hundred quid at least to draw something up that will work, machining will cost you up to around £60 per hour to make it. Say 10 to 15 hours, if they are a good machinist. The easy bit is you supplying the cash.
The other way is having good friends with the skills and resources to help you out for the cost of a pint or a packet of fags.
I have the plans for a basic fwd/rev crash gearbox if that helps, but unless you can cut your own gears, it will get rather expensive. At least £50 for the gears, maybe more.
Still want to reverse your boat?
Bogs
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Have a look at model truck stuff. You can get a clutch and reversing gearbox for sensible money. I posted details either here or in The Other Place a couple of years ago.
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Geralds suggestion is about the only workable one.
If you are thinking of reversing a prop in an effort to use it as a brake, forget it, all it will do is cavitate. It would suck air down from the stern, scream the nuts off the motor and be totally ineffective!
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No, it will put enormous stress on, and consequently destroy the motor.
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How about a jet drive with reversing bucket?
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You aren't going to get a jet drive for a 7.5cc glow, unless you make one yourself.
Dave Marles does one for a Zenoah, but it still begs the question, Why on earth would you want to go backwards with an IC boat?????? It boggles the mind...
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You aren't going to get a jet drive for a 7.5cc glow, unless you make one yourself.
Like this... :}
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You aren't going to get a jet drive for a 7.5cc glow, unless you make one yourself.
Like this... :}
Yes, but you are a master craftsman, this person is just starting out ;)
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Hi
I have seen a glow engined boat fitted with a variable pitch prop, it was a shop bought item, I think made by Gruapner, the motor was a 10cc .61 ?. It worked very well. Why ? well it was fitted in a fishing trawler. It was at the model weekend at Breen Sands some time ago. So it can be done, and worked very well. Not sure if variable props are still available though. They can be made, but some metalwork and lathework experience is going to be needed. I am actually coverting a glow engine to spark ignition to use in a model I am working on (its an old cabin cruiser)and reverse and stop would be handy, so may go this route myself. I am trying to replicate an old model I used to see sailing around Mote park many years ago, it was a Sea Queen with a Gannet engine, But thats another story. All the best John
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Google "HPI Savage reverse module". Designed for use in IC trucks and costs £50-60. As I understand it, it's an epicyclic gearbox that will change smoothly from forward to reverse. It's ready made and appears easy to install.