Brian's Donkey Engine

[SBWHART]

Hi Brian that looks real good, i like your idea of actualy putting an engine to work, I've long toyed with the idea of coupling an engine up to a rolling mill.

I thought my popcorn engine was a little small on the cylinder bore, I put a pressure gauge onto the air line to see what it took to run it and got 10 psi and 20 psi with the governor connected, with all my other engines they will run at less than 3 psi, the over crank wone the competition and runs at 1psi, It may be worth considering increase the cylinder bore by couple of mm, there is enough room to take this without having to increase the overall size of the cylinder.

Stew

 

[Brian Rupnow]

Pat and Jason---I have to agree with both of you. What will actually happen is that I will increase the distance between the cylinder and the crankshaft, thus moving the cylinders out farther to the left from the centerline of the boiler. What I have shown in that quick "lash up" was based on the rod length on the original Popcorn engine. If you look at the picture in post 310 you will se that that donkey uses a much longer connecting rod. Jerry---That style of crosshead guide was used on many "factory horizontal" engines. As far as the bore is concerned, the 1/2" bore is more than enough when you consider that it becomes a two cylinder engine in this configuration. Here is a configuration with longer con rods and much improved access to the valve bodies.

 

[Steve J]

Brian
I am in the process of making the two drum steam donkey from the plan book by Willaim Harris from Village Press. It is a pinion drive to both spurs , has a rachet disc on both drums and a brake band on both drums. The brake bands are made of hose clamp bands with over center devices to tighten them up. Am on page 14 of a 54 page plan book so have a way to go. There are also capstan drums on both winch drums which I think are keyed to the axle so they will pull when the clutch for the drum is disengaged.
steve

 

[JorgensenSteam]

Brian-

Looks good.

 

[tel]

... or you could get really anal and try this .....

 

[Captain Jerry]

Brian

I hope you don't mind all of the advice, but if you proceed with the latest plan, you will have limited the machine to a single drum. To power a front drum, the pinion/crankshaft has to be in front of the main drum.

I don't think you need to worry about removing the steam chest. American Hoist cast the steam chest integral with the cylinder and used the steam chest (with an integral flange) to attach the unit to the deck. The cylinders were hung outside the deck frame. Just the steam chest cover needs to be removed to set the valve. You might need more room to see but unless you are building a live boiler, you will have plenty of room for setting the valve by removing the dummy boiler.

As to the X-head, I am familiar with that type in many applications. What I should have said to be more clear is there was at least one manufacturer of steam donkeys that used that style so it would be historically accurate as to style but not in all detail. The one that I remember seeing looked more like the one you used on your twin horizontal.

Steve:

The capstans are keyed to the shaft and turn when the engine turns. They were operated by a helper who would throw two or three turns of rope on the drum and manually tail the manilla or hemp rope to control the load. The drum turns but does not pull the rope until the helper applies tension to the tail. Not a place to use wire rope. Usually used on a yarder or gin pole application to swing the boom. Precise control of the boom required the helper to use both drums and to slip one against the other to swing right/left/stop.

Jerry

 

[Captain Jerry]

Hear is a rear view showing the outboard mounting of the cylinders hanging from the steamchest.

Jerry

 

[cfellows]

Great looking project, Brian. I'll be following along!

Chuck

 

[Harold Lee]

Brian - I have building a Steam Donkey on my bucket list as well. A couple of years ago I went to Hillsboro Oregon and visited with Merv Johnson who wrote the book "In Search of Steam Donkeys". My grandson and I spent the day with him. He has a trailer sized model of a donkey and we spent a bit of time with it. I also went to a logging camp (Camp 18) which is on highway 26 at milepost 18 on the Oregon coast and spent time there photographing and measuring many of the donkeys they have there. One of the original donkeys had a single cylinder vertical engine and the drum was horizontal. They were interconnected by a large bevel gear much like a cement mixer. Village Press also put out a small book "The Steam Donkey Engine" by William Harris that has a set of plans for building one.
http://bay-com.com/product-info.php?pid164.html
If there is anything I can do to provide you with information, Please let me know. I'll be following your build with great interest.

Harold

PS - I'll contact you off list for some additional information.

 

[joe d]

Brian

There are two donkey engines on display at the Logging Museum in Algonquin Park... gives you an
excuse to visit your old stomping grounds.

Joe

 

[Brian Rupnow]

I don't usually do this much "flippin and floppin'" when I first get involved in a design, but its taken a lot of rearranging and moving things about to end up with a model that is pleasing to my eye, allows access to the valve boxes, and more or less resembles one of the original donkeys. I think that a lot of the eye appeal in this model is in the bearing stands and the base, so I have spent quite a bit of time on them. I have altered the crosshead guides a bit and put on a couple of rather nifty looking stanchions to support the outboard end of them. You will never wander down an old logging road and see one quite like this, but then again, this is not intended to be an exact model. This is a model that captures the essence of the old steam donkeys, and will have a functioning winch, clutch, and brake mechanism.----But will still be within the capability range of mid range skilled model engineers.---Brian

 

[JorgensenSteam]

Brian-

I think you have done a good job of capturing the look and feel of the old steam hoists.

The design is looking very good.

 

[tel]

The layout looks good to me - very much in keeping with the old 'uns.

 

[Brian Rupnow]

Here we have it in all its naked glory, without the engines and boiler.

 

[Brian Rupnow]

Now, for all of you guys that are setting around bored, suffering from mid winter blues, and just dying to begin a new project------. These are all drawings for the Donkey engine that I know are correct and won't change. How do I know?---Because they are the exact same drawings I used to build the Popcorn engine, and it runs extremely well. There are going to be some drawings that I have yet to develop, and actually make the parts before I will turn them loose on an unsuspecting public, but these ones I am certain of.---Brian

 

[Brian Rupnow]

And here's another bunch of Donkey parts---

 

[Brian Rupnow]

And more---Damn, there's a lot of parts to a Donkey!!!

 

[Brian Rupnow]

And my last bit of Donkey Doo for today---

 

[Brian Rupnow]

My nice long design contract across town is limping to an end. The design work is all finished and I'm just waiting for all the various machined parts and weldments to be completed and brought "in house" so I can supervise/orchestrate the final assembly of the machine. In the meantime, I get to spend quite a bit of time at home, and consequently get to spend day time hours designing my toys. In a way I am covering new ground here, as I have never completely designed a steam chest and slide valve on my own. On all of my previous steam engines I have copied other peoples designs. This time, using the original Popcorn design by Stew Hart as a starting point, I am changing port sizes and eccentric travels, and a host of other related items. I haven't posted drawings of any of these changed items, because I first have to convince myself that the changes I have made will work properly. I'm off now to the bank to pick up a wheelbarrow full of money to buy brass at my local metal suppliers. ;D ;D ;D

 

[Captain Jerry]

Brian

It's a lot easier to "flip" and "flop" in SolidWorks than it is on Craftex. Thats the beauty of 3D design.


Jerry