Launching a new project...

[Brookesy]

Ok, so I'm on a steep learning curve and reading everything I have time for. An amazing amount of information here. Thanks everyone who contributes. Launching (pun intended) a new project...

Long term my goals are the Trojan Mk II vertical engine and hopefully Minnie traction engine but I need a simpler engine as a starting point. Plans for both Trojan and Minnie are on the way and the workshop is nearly complete.

While I'm waiting I thought starting plans for a 1/12th scale 21ft Steam launch might be a good idea.

Full-size displacement 3467 lbs = 1572.6 kg
1/12th scale model 1572.6/12/12 = 10.92 kg (I think, please correct me if i'm wrong)
or is it 1572.6/12/12/12 = 0.91 kg?

My first problem to solve is a suitable scale looking engine and vertical boiler. In photos of full-size steam launches of around this size the engine seems to be fairly imposing and taking up a fair bit of space in the hull. I intend to build the engine and later might build the boat to put it in.

Any suggestions for a suitable engine/boiler to build?

 

[fcheslop]

Malcolm Beak did a very good write up in one of the model boat mags mid 1980s for his MB22 engine.Its a double acting twin 3/8 bore and stroke and is a very good little engine for marine work
Malcolm also did three boiler designs a simple pot,a vertical and a center flue for this engine and fitted the plant into Vic Smeeds River Queen hull and she clips along . there is also some videos of the MB22 on utube
You can contact Malcolm on Paddle Ducks or Model Boat Mayhem he is a very approachable gentleman
Iv recently built the MB22 and fitted her with a scotch crank pump arrangement to go into a Thames launch
The Trojan is also a nice engine to build but unless you make a self starting set up like the French Typhoon engine is obviously wont self restart when reversing and would need a gearbox or a Kitchener rudder.
For most of my semi scale boats I prefer simple double acting twin oscillators as you get for/reverse from one servo and they are very reliable on the water .Just saves wet feet and frustration at the pond side .
J P Duval has some nice free marine wobbler drawing on his site
Hope it maybe of some use
cheers

 

[Brookesy]

Thanks Frazer. Great reply. I now have a lot more information to read through and the MB22 plans. I once had the River Queen plans and built an electric powered model but can't find any of my old model boat stuff.

 

[fcheslop]

I also built and still have my River Queen although I fitted a V twin wobbler along the lines of P Arnotts design with his center flue boiler
I know all about loosing drawings as I lost a lot during a house move:wall:
cheers

 

[Brookesy]

Oh yeah, I'm hearing you. I should never 'clean up' the shed and never 'have a throw out' when moving house...

 

[fcheslop]

Yep keep those could be usefulls as you only need them the day after you chucked them out:hDe:

 

[Brookesy]

So I've made some progress on my first engine - fired up the lathe and mill in anger on the weekend. Taking the basic concept of 'Steve's Simple Engine & Boiler' linked on here somewhere, searched through the shed to find materials already on hand, re-drew to something that might work, & hooked in. Various bits of brass plate, an old model boat prop shaft, a 6mm s/s bolt, a chunk of 25mm bronze bar and various BA and other small fasteners. Taking a design-as-you-go approach it could go well, or it could go in the bin. Who knows but it's all about learning/re-learning the skills I need. Will post a drawing and maybe some photos when I can.