Sangsetia

[Steve Walker 1Participant @stevewalker1]

[Steve Walker 1Participant @stevewalker1]

Hello everyone,

After several builds of DG's models, including Sea Princess, I have decided to go for something bigger and have plumped for the Sangsetia PX boat – because I found plans with the relevant magazines. It is a David Metcalf design which featured in MB in 1986. I have started the 'double diagonal' hull and intend following the instructions in the mag.

However I would like some early advice on power plants. In the article it says that he wanted to fit Falcons but couldn't as they were no longer available. It doesn't say what he did fit only that they were ' similar to 540's but use less amps under load'. He powered them with twin electric speed controllers and 5 1.2v 7.5 NiCads and used 4 blade props which he subsequently upgraded to 'Navy' style to give the scale speed of 25knots.

Can someone tell me what this turns into 30 years later?

As a beginner I am a bit nervous about the twin prop idea, but am keen to give it a go, however I would like to get the appropriate bits early so that I can make any adjustments that might be needed to fit modern products. Does anyone have any other suggestions, not about what to build, but how to make sure I do it justice?

Thanks, Steve

[Dave MilbournParticipant @davemilbourn48782]

Steve

Here's the lowdown on operating twin motors **LINK**

Dave Metcalf was fond of what he called "low-drain 545 motors" but he was never more specific about them than that. If you could give us a little more information on Sangsetia e.g. length, beam, diameter of props then we might be able to suggest an alternative motor type.

Dave M

[Steve Walker 1Participant @stevewalker1]

Thanks for that Dave, good starter for me.

The model is 44" X 9" and he suggests using 2 X 13" X 4BA (?) prop shafts with 2 1/2" props which he changed to Navy (?) type. I have attached photos of the relevant bits of the plans and a cover picture of what I'm aiming for. My double diagonal hull is more or less complete but before I go further I'm wondering what would be best to use now, ie 30 years after the plans were published.

Any handy tips on fitting the shafts so they are parallel would be welcomed too.

[Dave MilbournParticipant @davemilbourn48782]

2 1/4" (55mm) 4-blade props would be a handful for a stock 540 motor. The general rule for brushed motors is not to fit a prop which is bigger in diameter than the case of the motor – or 36mm for a 540 motor. Malcolm Frary has an additional rule which says not to use a prop which has more blades than the motor has armature poles – in the case of a stock 540 the latter number is three.

I'd be inclined to fit 2" (50mm) 4-blade props and run them with a pair of 775 5-pole motors (the faster version) on 9.6v. Granted the prop is still a bit bigger than the motor but those motors have a load of grunt. I think that 12v might be a bit too fast but you're always at liberty to use 12v and reduce the throttle top speed. Whatever you do please don't be tempted to fit SLA batteries. This is a planing boat and needs their weight like it needs a hole in the bottom of the hull. NiMH packs of 5000maH are available – also from Component Shop – and a pair of those should last a couple of hours. **LINK**

4BA shafts are long gone, and you'd also be hard-pressed to find props or couplings to suit. For 13" length I'd go for M5 shafts. Fitting them parallel is no more complicated than making a pair of identical spacers drilled out to suit the diameter of the prop tube (generally 8mm), with two holes spaced apart the same distance as between the shafts. Slip one over each tube, front and back, to keep them at the same spacing while you epoxy the tubes into the hull. Job done.

Dave M

[Steve Walker 1Participant @stevewalker1]

Thanks for the suggestions Dave. Armed with some positive ideas I'm now off to re-read some of your other papers on voltages and maH's to try and work out where I'm going with this hobby and decide which might be best or at least most versatile. At this stage I also note what you say about the different types of build and the speed v ballast point. I will need to give some thought to what sort of model I favour. I have had so much fun with the granddaughters and DG's EeZebilts that I'm going to have to choose between quick and cheerful sailing or spending time on a more substantial build.

Anyway that's straying away from the point so back to the research….

Cheers, Steve

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