Search found 882 matches

by barts
Sat Apr 06, 2019 4:20 am
Forum: Technical - Engines and Boilers
Topic: Desuperheater question
Replies: 15
Views: 1890

Re: Desuperheater question

A radiant superheater is definitely subject to burnout if there's no steam going through it... so a hot (wood - not readily turned down) fire. I think your best solution when stopping the engine for a while is to 1) stop firing a while before if you can predict it. 2) open the firebox door and keep ...
by barts
Tue Feb 12, 2019 6:15 am
Forum: Technical - Engines and Boilers
Topic: Favourite cylinder lubrication
Replies: 14
Views: 2297

Re: Favourite cylinder lubrication

I use the green velvet oil PB &J 460 but they seem to be out of business.

- Bart
by barts
Thu Jan 31, 2019 3:13 am
Forum: Technical - Engines and Boilers
Topic: What water speed do you work with in monotube boilers?
Replies: 5
Views: 895

Re: What water speed do you work with in monotube boilers?

Required water speed depends on tube diameter - you must have turbulent flow, which means a Reynolds number (dimensionless) of at least 4000 in a tube. This helps prevent overheating of the tube at very high firing rates. Note that this requires that there's water flowing through the tubes whenever ...
by barts
Sun Jan 20, 2019 7:55 pm
Forum: Technical - Engines and Boilers
Topic: Con-rods and length
Replies: 31
Views: 3387

Re: Con-rods and length

One (lonely?) thought that is running round my head is that the taller the engine is, the more flex there must be in the pillars; larger dia. will help but at some point diagonal bracing will need to be applied. This is true. Flex in a beam varies with the cube of the length for a given cross secti...
by barts
Sat Jan 19, 2019 9:10 pm
Forum: Technical - Engines and Boilers
Topic: Con-rods and length
Replies: 31
Views: 3387

Re: Con-rods and length

Audel's suggests that the normal range is from 2:1 to 2.5:1 - you're in good company no matter where you go. Reciprocating weight is seldom an issue on our engines other than for vibration. I do wish the Burleigh compound in Rainbow were taller; there's little room for proper valve guides & glands o...
by barts
Sat Jan 19, 2019 4:24 am
Forum: Technical - Engines and Boilers
Topic: Con-rods and length
Replies: 31
Views: 3387

Re: Con-rods and length

Longer rods are generally better; 2.5:1 is not too long by any means. Herrreshoff engines were well known for long connecting rods. If you have the space, go right ahead. Long rods may need slightly larger sections to prevent Euler buckling.

- Bart
by barts
Sat Jan 19, 2019 4:07 am
Forum: Technical - Engines and Boilers
Topic: Opposed-Piston Engine Project - The Steam Version
Replies: 41
Views: 5680

Re: Opposed Piston Engine Project - The Steam Version

The most flexible steam engine of all is probably a twin single cylinder w/ cranks 90 degrees out of phase and 75% cut-off or more - these were often used as hoist or elevator engines. However, that doesn't do much for steam economy. Triples and quad expansion engines were basically designed to run ...
by barts
Sat Jan 19, 2019 3:43 am
Forum: Technical - non Engines and Boilers
Topic: Milwaukee M18 Transfer Pump
Replies: 2
Views: 738

Re: Milwaukee M18 Transfer Pump

I've used one of those small 12V impeller pumps to do various utility pumping jobs. If you need one regularly, I'd just install it somewhere hidden and properly wire it into place. The impeller pumps get grouchy if you run them dry and they do pound one's battery, so if this is an issue, consider a ...
by barts
Thu Jan 17, 2019 7:45 am
Forum: Technical - Engines and Boilers
Topic: Axial Thrust & Engine Bearings
Replies: 3
Views: 588

Re: Axial Thrust & Engine Bearings

For our steam boats, rule of thumb is that a pillow block bearing will handle any thrust loads from a prop that fits on that diameter shaft.

Engines w/ journal bearings w/o integral thrust bearings (or pillow blocks :)) should have a pillow or flange bearing to handle the thrust.

- Bart
by barts
Thu Jan 17, 2019 2:57 am
Forum: Technical - non Engines and Boilers
Topic: Prop Step Up
Replies: 10
Views: 1550

Re: Prop Step Up

Otter has the same problems w/ her 2.5" x 2.5" single as the counterweights are too small; the old 2" x 2.5" single acting twin was much smoother at speed, of course. I went to a 16"x20" prop from her old 13" x 17" because the new engine ran away w/ the small prop, but at full throttle (180 psi) th...