Steam engine

[Chriske]

Hi guys,

Planning toward next school-year(already...;D).
My colleague and I want to copy 1:1 the very first Benz auto-mobile. This car will be Co-work between my workshop(mechanics) and my colleague's workshop(welding). Looking forward to it...!
This is what it will look like :
http://www.daimler.com/Projects/c2c...49829_800_530_benz_patent_motorwagen_1886.jpg
The only change in this project will be its engine. I will not build a IC engine as in the original Benz. Instead I'll make a steam engine. This engine should be powerful enough to transport two grown people. We're not planning to break records, but we would be very pleased if it will run as fast as 10 mph.
All drawings of the car itself are almost done, we will focus now on that engine.

Ok, some questions to you experts now..
I already built a few working Stirling engines, but steam is completely new to me, so...
How powerful should this engine be..?
Are there any drawings to be found on the internet..?
Best to make one large piston or would it be better a few smaller pistons..?
Is it advisable to make a radial engine or not..?
Some more will follow...

Chris and Wouter

 

[cidrontmg]

Make it 2 cylinders (at least). Then it will be self-starting. I'd think minimum would be 2 cyls with 50 mm dia and 100 mm stroke (2 x 62.5 cm3). Forget a radial engine. Radials need lots of steam (air), and it is only single-acting = lots of wasted steam.
You eventually want a boiler. I think it's a very good idea to consult first (before even you buy anything material) your club boiler inspector about this. There are many safety issues to think about, like insurance, required standards and norms, materials, fittings, appropriate techniques, etc. A biggish boiler is perfectly safe to build and construct, and run with the streets, but it still is capable of a lethal weapon. Consult with the boiler inspector, and comply religiously what the inspector says.