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Author Topic: Engine advice  (Read 2354 times)

damjan

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Engine advice
« on: April 29, 2006, 03:54:21 PM »

HI there

I guess nitro/gas engines aren't particularly popular judging by the number of topics here.

Anyway, I would like some advice on buying an engine for a Dumas PT109 which is 48inches in length. They recommended a 4 stroke 0.65cu in engine (an O.S which is far too expensive). I would like to use a 4 stroke as apparently they produce a more realistic noise (the boat will mainly be used on the sea so I won't be upsetting any wildlife). However, I am having a really hard time researching any engines. There does not seem to be a good website that talks about the different engines or manufacturers, preferably in the UK.

Could anybody shine a little light on this for me?

Thanks very much in advance

Damjan
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RC John

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Re: Engine advice
« Reply #1 on: May 02, 2006, 05:15:47 PM »

Don't ask me where the first reply went to, so I will try again.

Four strokes are aero only? - the difficulty is water cooling.

The cheap end of the range are SC, ASP or Leo.
The SC/ASP's will run at 16000/17000 rev/min but the Leos will run at 24000 rev/min.
See ]http://www.justengines.unseen.org/Leo.htm for the Leos and ASPs.The cost are Leo £70 and ASP £65 but the Leos are either 3½cc or 7½cc.
I have bought two Leos 7½cc this year and the last one is fitted to an AeroMarine Challenger 21 - that boat really does move.

So now I will try and post this or possibly loose it in the ether again.
John
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glennb2006

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Re: Engine advice
« Reply #2 on: November 13, 2006, 11:22:18 AM »

Hi There,

for a boat that size you might want to try a petrol motor, the Zenoah range is very good, loads on ebay normally. You can get quiet pipes for them.

See below link for engine advice, Forum has many, many pages of engine Q&A's, if you trawl through you will generally find the answers to most questions.

I agree with John, not aware of any marine four strokes.

The SC engines mentioned are not bad and quite competitively priced, but hard to start when new. Happy hunting.

The link: http://www.prestwich.ndirect.co.uk/

Glenn
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OneBladeMissing

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Re: Engine advice
« Reply #3 on: November 13, 2006, 05:36:35 PM »

I don't know of any marine 4-stroke engines. My brother used O.S. and Saito 4-strokes in 'planes and told me they tended to run a bit hot.
Some of the (I think) Leo marine engines are available with recoil starters fitted. I don't know how good they are but it sounds better than messing about with starting cords or buying electric starters and batteries.
Even though the PT-109 is 48 inches long, it's not wide enough to handle a Zenoah or a large plowplug engine. A 7.5cc glow motor should get it up to scale speed though.
 
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OneBladeMissing

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Re: Engine advice
« Reply #4 on: November 13, 2006, 07:06:42 PM »

Are you sure the Dumas PT-109 is 48" long?   The one I've seen advertised is 33" by 9" beam.
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anmo

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Re: Engine advice
« Reply #5 on: November 13, 2006, 08:02:03 PM »

Are you sure the Dumas PT-109 is 48" long?   The one I've seen advertised is 33" by 9" beam.

You're both right, Dumas make two PT109 kits, a wood 33" and a fibreglass 48", don't know if both are sold here in the UK though. Someone (Dynamic?) in the US used to make both wood and fibreglass PT109 kits in 1/24th scale, hull length was about 40". Their GRP hull was OK, but their wood quality was dire, what I saw looked like reject stuff from a packing case manufacturer.
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RC John

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Re: Engine advice
« Reply #6 on: November 15, 2006, 04:40:21 PM »

This boat in the picture is an AeroMarine Challenger43 fitted with a Leo 46 (7½cc) turning an X452 prop. It is extremely fast!
It can still run at a good speed turning an X457 prop - this size of prop is normally found on a 15cc  boat.
Pull starts on Nitro engines are normally on small engines only but Leo do make one in the 46 size.
The kit recommended a OS 65 (10cc), for £70 the Leo 46 will do the job. Put a Just Engines Purple Pipe on it and you will have NO noise problems either.
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martno1fan

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Re: Engine advice
« Reply #7 on: November 17, 2006, 05:31:52 PM »

try a strimmer engine i just bought two off ebay both brand new 28 cc never run and they both started up easy.i paid £15 each for them and there are still some available.mines going in a deep v im going to scratch build from plans i have of thes two i havent made my mind up which one yet.
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