Woodson vertical w/reverse`

[chucketn]

I'm drawing up and planning to make the Woodson Vertical slide valve engine from Popular Science, 1947.
Has anyone built this engine? I having trouble understanding how to set up the eccentrics. There has to be a better way.
This engine has what I believe to be a Stevenson Link for the reverse part. It use 2 eccentrics that are riveted together. Is there a better way?

 

[Brian Rupnow]

 

[chucketn]

Brian, your CAD and animation skills are amazing!
That is the engine, right down to the reversing gear.
Have you built this one?

 

[Brian Rupnow]

Yes, I built a double cylinder engine with reversing link. I can't take credit for that model though. I just entered "woodson vertical slide steam engine with reversing" into google search engine and it found that for me.

 

[Brian Rupnow]

Chucketn--Here is a link to my build.---Brian
http://www.modelenginemaker.com/index.php/topic,7419.0.html

 

[Jasonb]

Chuck there is an Woodson engine in .STEP format on Grabcad you can downlaod to save drawing it.

 

[chucketn]

Thanks Jason. I am using the drawing session to build my design/modeling skills with Fusion. I will look at those files and experiment with importing step files.

 

[chucketn]

I just finished re-drawing the eccentrics for this engine as one piece, each half offset 34 deg from horizontal. Now I wonder if I should have left them as separate pieces. Would the 2 eccentrics as separate parts make it easier to adjust the engine timing?

 

[Brian Rupnow]

One eccentric is for forward, one is for reverse. When I built my engine I found it really great to be able to adjust the eccentrics individually.

 

[Jasonb]

By making them as one with the correct 34deg each way you only need to set the timing in one direction and the other will take care of itself so half the work and with the grub screw in the boss far easier than having it in the actual eccentric which usually means taking the strap apart to adjust. If you place the grub screw mid way between the two 34deg angles then just position that opposite the crank pin and you are set, much like the position of the keyway in the drawing I posted on MEM

 

[chucketn]

Thanks for your comments and help, Jason.

 

[chucketn]

Well, I'm now working on the last part, the eccentric rod. I used the model of the valve rod to speed up the drawing, I just changed some dimensions to suit. One thing I haven't figured out is how to get the offset in the eccentric rod. Fusion users help me out!View attachment 103188

 

[Jasonb]

In Alibre I would draw the path of the bend, draw the section of the part at one end and then use "Sweep" to get the shape to follow the path. Not sure what they call it in F360.

If you also want it to taper from 3/16 to 1/8 along the path then draw the section at each end and then use "Loft"

 

[Jasonb]

Just tried it in F360 and its the same as Alibre, draw the path as 3 lines with the junction filleted. Draw the section (profile) on a right angled plane and then go to Create and 3rd option down is sweep. Select the path and the Profile and click OK

 

[chucketn]

I split the straight one I created into 3 pieces. I copied the top yoke and the bottom threaded piece and moved the copies to the side of the original.
I then offset them by the 3/32 as per the above drawing. I then made a spline like a lazy 'S' from the center line of the clevis piece to the center of the threaded piece.
Next, I used the 'loft' feature to extend the profile of the top piece to the bottom piece. Not perfect, but I think it will work. The main purpose of the exercise is to create an animation like the one Brian posted.
If I'm successful, I'll post it here.