Reworked Horizontal Engine

[cfellows]

I reworked this engine to experiment some with my air valve. I polished it up a bit in the process. It's running pretty good now although it bogs down and almost stops when I give it too much air pressure. Gotta experiment some with the spring in the sliding piston valve. I'll post a video later.

Chuck

 

[chuck foster]

hey chuck thats looking good!!!!

i was just at a small steam show and a guy had a model of an in line four cylinder running on air.
when i asked him about the valves he said they where "just" steel balls "a-la chuck fellows" 8)
so i guess he must be on this web site unless you are on other sites posting plans or ideas for you engines!!

i guess it just goes to show you how small this world really is.

by the way, the show was here in the toronto area.

just thought you would like to know that you have influenced at least one guy up here.

chuck

 

[Bogstandard]

Chuck hasn't just influenced one guy, he got to me big time.

I still have to finish my variable cam engine off (personal stuff got in the way), but it was run again this last weekend and is on my major finish list.

I can honestly say Chuck, your designs and manufacture are like a breath of fresh air, getting clean away from the norm. All done to perfect precision.

John

 

[cfellows]

Thanks, John and Chuck. Always appreciate your comments!

I eventually want to build all manner of models of internal combustion engines including a 3 cylinder inline (Fairbanks), 4 cylinder inline (Cirrus), 3 cylinder radial, 4 cylinder opposed, a v-twin and a v-4, all using my single push rod poppet valve with sliding piston valve for the exhaust and all running on compressed air.

Here is a video of the Horizontal Single. The hiss of escaping air is a small hole in the plastic tubing. Also makes the engine run a little eratically!

[ame=http://www.youtube.com/watch?v=CXH2nNLmBXo]http://www.youtube.com/watch?v=CXH2nNLmBXo[/ame]

 

[bretk]

Chuck,.

Awesome Video :bow: :bow: :bow: I Love that Sound of your valve mech. Saw the Gearing in the video, how did you set up the gearing and cam? Do you have any photos or drawings of that ? I really would Like to Build a version of that engine!

Thanks Bret

 

[Brass_Machine]

Nice! how does the air valve work?

Eric

 

[cfellows]

Chuck,.

Awesome Video :bow: :bow: :bow: I Love that Sound of your valve mech. Saw the Gearing in the video, how did you set up the gearing and cam? Do you have any photos or drawings of that ? I really would Like to Build a version of that engine!

Thanks Bret

Bret,

Here is a picture of the cam and gearing arrangement. Both gears are 48 pitch. The primary gear is pinned to the crank with a roll pin. The secondary gear rides on a stationary shaft held in place by the setscrew on top. The cam is made from brass and forms the hub of the gear. A single screw through the cam lobe holds the cam and gear together.

 

[bretk]

Chuck,

So is the cam gear just 2x the diameter of the other? thus giving 1 power stroke every other revolution? Did you cut your own gears, or are they ready made?

Sorry about all the questions, :

Bret

 

[cfellows]

Nice! how does the air valve work?

Eric

This description is taken from an earlier post I did. Thought I'd just repeat it. I've made a change from the pictures below. The new design has two holes into the cylinder from the sliding valve. This allows a small amount of high pressure air to escape before the sliding valve closes off the exhaust. This provides more of a pop when the engine "fires".

Only a single push rod is needed to activate the air inlet valve at the top of the stroke. Once opened, the inlet of high pressure air pushes the free piston (purple) in the head downward closing off the exhaust port and exposing the cylinder inlet to the air input. This simulates the firing cycle. At bottom dead center, or before, the inlet valve closes and the spring behind the free piston pushes it back to the top. This exposes the cylinder inlet to the exhaust port and as the power piston returns to top dead center, air exhausted out the exhaust port. As long as the inlet valve stays closed, the power piston can travel up and down as many cycles as wanted with little air resistance since the exhaust port stays open as long as the air inlet valve is closed. This valve arrangement works for 2 stroke, 4 stroke, 6 stroke, or hit n miss. You only need to worry about the the inlet valve timing - The exhaust takes care of itself.

 

[cfellows]

Chuck,

So is the cam gear just 2x the diameter of the other? thus giving 1 power stroke every other revolution? Did you cut your own gears, or are they ready made?

Sorry about all the questions, :

Bret

No problem on the questions... ask as many as you like. Yes, the driven cam gear has twice as many teeth as the primary gear on the crank. The gears were picked up on eBay although they would be easy enough to make.

Chuck

 

[Bogstandard]

Hi Chuck,

I don't want to hijack, but for Bret and Eric here is my meagre offering that shows how the geartrain and cam works.

Slightly different firing design to Chucks, but using Chucks design for the head valve, but split into two parts, the poppet valve and the sliding piston. Just to allow me to change the firing cycle by cam change.

[ame]http://uk.youtube.com/watch?v=EFfm9L90Tyw[/ame]

Chuck has really come up with a wonderful design for the firing of these engines.

John

 

[shred]

FWIW 48DP gears are available in 12T through 35T sizes from radio control model race car shops if you aren't up for making them-- There's a picture of some on the Slightly Loco thread.

This valve definitely on the list to try-- but where do the steel balls go? Replace the floating piston?

 

[cfellows]

This valve definitely on the list to try-- but where do the steel balls go? Replace the floating piston?

Yes, you can use a steel ball instead of the sliding piston. In my most recent design, where I have two holes leading from the sliding valve chamber to the cylinder, the sliding piston has the advantage over a ball in that you can change the length of the piston to alter the timing of opening and closing the ports to the cylinder.

You could also replace the standard poppet valve with a steel ball and a push rod to push the ball off it's seat to admit high pressure air. That's the method used by Liney on his Halo radial engine.

Chuck

 

[cfellows]

Here are some drawings of my latest design using 2 ports from the sliding piston chamber into the cylinder

The first picture shows the poppet valve closed. Spring pressure on the piston valve will keep it to the left exposing the right cylinder port to the exhaust side. The main piston can be going up or down, doesn't matter. Air will enter and exhaust through the exhaust side as long as the poppet valve is closed.

The second picture shows the poppet valve has just begun to open. The main piston is near top dead center. The sliding piston valve has begun to move to the right. As you can see, both cylinder ports are slightly open, the one on the left admitting high pressure air from the open poppet valve, and the port on the right exhausting part of that high pressure air through the exhaust. This is what gives the engine it's popping sound.

The third picture shows the poppet valve fully open and the sliding piston valve has now been pushed to the far right. The port from the cylinder to the exhaust is now completely closed so all incoming air is directed to pushing the piston down.

For a slow running running with better sound effects, the poppet valve should open slightly after top dead center. The cam lobe should be quite narrow and pointed to hold the poppet valve open a minimal amount of time. Best results are obtained with a quick rise and short duration.

Chuck

 

[cfellows]

I'm starting to take some pictures of the engine parts disassembled. I'm also working on my photography! I have a Pentax Digital SLR and it's got more bells, whistles, and settings than 747. I just figured out that it has white balance based on different types of light, so hopefully my pictures will get better.

Here's the engine with some of the parts removed.

A closer look at the cam & gear train.

And an even closer look. I know, kind of blurry...

Here's a closer look at the head. The set screw holds the valve assembly in place. The hole at the left of the opening goes straight through to the exhaust side. It's 1/8" diameter on the valve side and enlarged to 1/4" for the sliding piston and the exhaust.

Here's the valve unit, partly disassembled. Standard, automotive style poppet valve. The screws are 2-56.

And finally, for now, here's picture of the back side of the valve showing the two ports into the cylinder. You can see the sliding piston valve inside the right hole and the spring inside the left hole.

I'm going to put together some drawings and practice more on my photography.

Chuck

 

[bretk]

Chuck,

:bow: Awesome pics and details, it is starting to make alot more sense.

Thanks! -Bret ;D

 

[cfellows]

Here are some more pictures of disassembled engine parts.

First, pictures of the frame. I used 1/4" cold rolled steel and welded it all together. I would probably use a different technique, using 1/4" thick angle iron if I did it again.

Crankshaft with primary timing gear and left bearing block. I used ball bearings and the block is split on the back to clamp the bearing into place. The block mounting holes needed to be a little closer together since the one on the top is crowding the secondary timing gear mounting hole.

This is the timing gear side bearing block.

The bearing block opposite the timing gears. The exposed bearing goes to the inside of the frame.

Hear is an exploded view of the head assembly. The spring shown is 7/32" x 1 5/8" x .021" wire gauge. This spring is heavier than the one used in the video and it gives much better results. The spring actually extends most of the way through the exhaust manifold/pipe. The last 1/16" or so of the exhaust pipe is necked down to hold the spring in. The sliding piston valve is 1/4" diameter and 3/8" long.

Chuck