Search found 1069 matches

by barts
Tue Feb 08, 2022 6:32 pm
Forum: Technical - Engines and Boilers
Topic: Upscaling a Hasbrouck engine
Replies: 26
Views: 20499

Re: Upscaling a Hasbrouck engine

As speedy as Reciproca is, I must admit to losing a race to an oldster in a fine lined kayak. I'm not sure that he knew that I was even racing with him. How humiliating! Some fifty years ago, my dad and I mounted a tiny, lightweight outboard (an 1.5 hp AquaBug iirc - hard to keep running well) on a...
by barts
Mon Feb 07, 2022 8:56 pm
Forum: Technical - Engines and Boilers
Topic: Upscaling a Hasbrouck engine
Replies: 26
Views: 20499

Re: Upscaling a Hasbrouck engine

Note the similarity between the most efficient prop for a steamboat, and that for a human-powered boat:

http://recumbents.com/wisil/hpb/prop/default.htm

Some of the athletes are capable of outputs (for a short while) that exceed that of small steamboats.

- Bart
by barts
Wed Feb 02, 2022 11:42 pm
Forum: Technical - Engines and Boilers
Topic: Paddle Steamer Alexander Arbuthnot - 10HP
Replies: 1
Views: 2224

Re: Paddle Steamer Alexander Arbuthnot - 10HP

I've heard of the expression 'a bit agricultural' when it comes to pragmatic boat design, and this is an excellent example of just that :).

Nice video - thanks!

- Bart
by barts
Tue Feb 01, 2022 7:17 pm
Forum: Technical - Engines and Boilers
Topic: TWIN 32 x 38 mm - steam engine for small boats or canoes
Replies: 71
Views: 95110

Re: TWIN 32 x 38 mm - steam engine for small boats or canoes

Temperature limits for common aluminum alloys, esp. heat treated ones like 6061-T6 should be followed closely if strength or corrosion resistance is important. See http://www.matweb.com/search/datasheet_print.aspx?matguid=1b8c06d0ca7c456694c7777d9e10be5b for details. For saturated steam conditions, ...
by barts
Mon Jan 31, 2022 6:43 pm
Forum: Technical - Engines and Boilers
Topic: Valve Gear Simulation
Replies: 14
Views: 11775

Re: Valve Gear Simulation

For many years I have evaluated steam engine valve gears, and have often wondered why the Stephenson Valve Gear Mechanism is so prevalent. Does anyone know why? I've often wondered the same. The Marshal gear has the practical advantages you mentioned: that there are no sliding links or blocks; all ...
by barts
Thu Jan 27, 2022 9:21 pm
Forum: Technical - Engines and Boilers
Topic: Upscaling a Hasbrouck engine
Replies: 26
Views: 20499

Re: Upscaling a Hasbrouck engine

a simple engine of 3" bore and 4" stroke would produce 5 hp. This is exactly the dimensions of the 5 hp Semple engine, built many years ago. Somehow I don't know how that calculation can come out to 5. If you disagree with Ray's rating of the engine, say so. My scaling calculations are correct for ...
by barts
Wed Jan 26, 2022 10:35 pm
Forum: Technical - Engines and Boilers
Topic: Upscaling a Hasbrouck engine
Replies: 26
Views: 20499

Re: Upscaling a Hasbrouck engine

Power will scale linearly with displacement, thus it will vary as the cube of the linear dimension. So if you double all the dimension, the engine will produce 8 times as much power. In this particular case, you have a 2 hp engine and you want 5 hp, a factor of 2.5. So take the cube root of 2.5, and...
by barts
Wed Jan 26, 2022 5:22 pm
Forum: Technical - Engines and Boilers
Topic: Antonia Engine - Marshall valve gear
Replies: 4
Views: 6793

Re: Antonia Engine Valve Gear Identification

This looks like a Marshall gear driving rocker arms w/ valves at the ends of the engine, I'd guess to reduce length. The purpose for the two rocker arms/cylinder, slightly out of phase, is perhaps a riding cut-off. Note the integral flat plate heat exchangers as well. A very neat piece of design, ve...
by barts
Sun Jan 23, 2022 2:20 am
Forum: Technical - Engines and Boilers
Topic: TWIN 32 x 38 mm - steam engine for small boats or canoes
Replies: 71
Views: 95110

Re: TWIN 32 x 38 mm - steam engine for small boats or canoes

was your bearing an open or an closed type? I will use closed ball bearings on all eccentrics of my engine. They have a life time lubrication. I had a slight bit of side motion (.030) or so on the end of the eccentric arm as I used a rocker arm to drive the horizontal slide valve. Thus I used two b...
by barts
Wed Jan 19, 2022 3:22 am
Forum: Technical - Engines and Boilers
Topic: TWIN 32 x 38 mm - steam engine for small boats or canoes
Replies: 71
Views: 95110

Re: TWIN 32 x 38 mm - steam engine for small boats or canoes

Otter's old engine used a thin-line ball bearing on the eccentric - it was very smooth and easy to turn over, even w/ some steam chest pressure.

That engine lasted many years, and the bearing still feels smooth. A squirt of oil now and then took care of lubrication.

- Bart