Screeching Halt!

[BClemens]

I started working with the Excel "Locomotive Efficiency Calculator" and now I'm totally disgusted. Using the actual measurements for this engine I can never achieve an 'efficient' engine. "Ee" and "Eb" and "Eo" within optimum values the "Kt" will be far too low - in the 30's. Fudging some dimensions that still can be modified - it all goes to Hades. I can never get the 'optimum' values....

The copper boiler was a wash-out since everyone I talked with discourage that.... Now it appears the entire engine is "inefficient" and probably will be a failure. I have accumulated thousands of dollars worth of materials, castings and have hundreds of hours in machining time on a junk engine.

This is probably enough to come to a screeching halt on this. No point in building a problem.

[Atkinson_Railroad]

Sometimes we are our own worst enemies.

The Statue of Liberty was determined to be anatomically incorrect.

Yet it’s never been referred to as “junk”.

[BClemens]

The grate area to a lessor extent and flue tube sizes to a greater extent can be modified since suitable steel is being accumulated for a steel boiler. Plugging these modified values into the program does not do what is expected. A factor can be adjusted but invariably one or two others go completely out of the window. Is this the only source for basic design data for a 'miniature' steam locomotive? I'm thinking that a bourbon bottle may see the light of day this evening....

[BClemens]

Sometimes we are our own worst enemies.

The Statue of Liberty was determined to be anatomically incorrect.

Yet it’s never been referred to as “junk”.

I phrased that wrong - it is still in 'piles of parts' here and there in the shop so it's not an 'entity' yet - just little piles of pieces and parts - junk.

[BClemens]

I have and use JFN's book. Books by Martin Evans, Henry Greenly, and other early builders are consulted.... The proportions for the boiler were drawn from data in these books yet the excel program figures it inefficient. A statement in the description relates that the program may not be accurate...so why present a recipe for slop?

[Marty_Knox]

Efficient and Steam Locomotive are two mutually exclusive terms.

[SteveM]

If you modeled a bumblebee on a spreadsheet, it would say that it can't fly.

I would trust Evans, Greenly, et. al.

I remember seeing a model locomotive that was specifically built for efficiency trials - it was one of the ugliest things I have ever seen.

Steve

[BClemens]

Efficient and Steam Locomotive are two mutually exclusive terms.

Marty Knox - you need to write a book. With your experiences and know how, it would probably be a darn good seller. I'll buy the first copy.

[BClemens]

If you modeled a bumblebee on a spreadsheet, it would say that it can't fly.

I would trust Evans, Greenly, et. al.

I remember seeing a model locomotive that was specifically built for efficiency trials - it was one of the ugliest things I have ever seen.

Steve

A helicopter is similar: "bend the rules then find a fool"

[Bill Shields]

Locomotive Efficiency is measured in terms of smiles / miles

beyond that...what's the point?

[Builder01]

Are you building a published design?
Who designed it?
What exactly is it?
Are there working examples of it?
Are there working examples of it with a steel rather than a copper boiler? (I would consider this a significant modification for a first time build)

I ask these basic questions because I did much research before starting the build of my locomotive. It is a published design by Martin Evan. There are hundreds of examples of it in operation today. Lots of video on the internet as well. There is also a series of "build it" articles of this specific design.

I ran my dimensions and specifications through the same spread sheet (I think), it was far from perfect, but it was okay. The proof was the working examples the world over, not what the spread sheet said. But, to be sure, I have gone exactly with the original design. The boiler is copper, not a re-design in steel. It seemed foolish for me to design something that I have not even built one example of. If you have built several locomotive, then step out on your own and build it however you see fit.

David

[kcameron]

I would view the spreadsheet as only a measurement. One key thing you might be missing is those 100's of others with related designs may not be 'efficient' either. As I understand it, steam engines are not efficient but many work great. Think of it as your design is only 30%, but 'works great' may only need a 20% design efficiency.