Time for a Radial

[picclock]

Hi Chuck

That looks like a really neat build. In your first post on this engine you said

"It'll be compressed air using my ball slave valve arrangement."

Any chance of an explanation of how this works or a pointer to a drawing ?

Many thanks

picclock

 

[cfellows]

Chuck, that indexing fixture is amazing!! I love it!! Makes me wonder what else you have stashed away... :big:
Your engines coming along very nicely. I just love the look and sound of a radial engine.
Cheers
Jeff

Thx, Jeff. I've always tended to build as many of my own tools and fixtures as I can. For many years, I couldn't really justify the cost of commercially available stuff.

Looking real well Chuck ;D enjoying following your thread.

Stew

Thx, Stew, always enjoy hearing from you.

Sorry I haven't commented before Chuck, I've been rather waylaid by other things.

It is coming along very nicely, just like all your other engines have done, and I am sure you will have everything 'just so' by the end of it.

John

Hey, John, I was wondering last night where you'd been. Hadn't seen any postings from you on the board anywhere. Hope everything is OK. Thanks for your words of encouragemet!

Nice build ;D. I was looking at your connecting rod assembly and I thought that on a radial engine, one of rods should be solid ???.
On your drill press, if the index pin's arm has 3 holes, you wont miss the 2 on the table

Thx, Noiten. One of the connecting rods is solid. The inner end has a concave radius which fits solidly against the hub of the spool.

Hi Chuck
That looks like a really neat build. In your first post on this engine you said
"It'll be compressed air using my ball slave valve arrangement."
Any chance of an explanation of how this works or a pointer to a drawing ?
Many thanks
picclock

Thx, picclock. I've developed several different versions of the slave valve arrangement and if you do a search of this site on slave valve, you'll get a number of hits. The arrangement I'm planning for this radial engine is here:

http://www.homemodelenginemachinist.com/index.php?topic=3026.0

Chuck

 

[picclock]

Hi Chuck

Many thanks for the valve info, that's a really neat arrangement. :bow:

I love the simplicity of only having 1 port in the cylinder head, and the compact nature of the arrangement. Pure genius.

Best Regards

picclock

 

[nh_eng]

Chuck,

I am new to the model making scene, and I am in awe of your skill. I really enjoy seeing your setups, as from my point of view, the biggest challenge I have in any machining operation is how to set it up/fixture it. They say that you learn by your mistakes, and if there is any truth to this I should be learning by leaps and bounds, because I am making mistakes at an incredible rate.

Keep up the good work and thanks for the great postings - you are truly an inspiration to me.

Thanks for sharing,

Paul

 

[Brass_Machine]

I love the way it is shaping up. Looking good Chuck... I am enjoying it! :bow:

Eric

 

[wareagle]

Chuck, you have a nice looking radial taking shape. I am eager to see this one running!

BTW Slick indexing fixture you have. Incredible find! May have to "hotrod" the drill press...

 

[cfellows]

Thanks, everybody, for the kind words.

I spent most of today doing remedial work. Paying the price for getting in a hurry earlier on. I discovered the cylinder openings in the crankcase were .010" closer to one edge than the other. And, they varied in size by + / - .005". So I set the crankcase up again and enlarged all the openings so they were centered and equal in diameter. Of course, that meant that the spigot at the bottom of the cylinders was now too small, so I had to build them up by soldering short lengths of brass pipe on them and re-turning them to fit the new openings. Now they are all consistent and fit nicely. I feel much better now! 8)

So, finally some pictures with the engine in an upright position. They always look better when you get some fasteners in place.

Yeah, I know, including the picture of the B-17 which adorns my shop wall is a bit over the top!

The overall diameter of the engine is a tad over 6". Here's a picture with a soda can for size reference:

Chuck

 

[swilliams]

Looking great Chuck. The color from the brass cylinders gives a really nice touch.

Steve

 

[tel]

Nothing to be ashamed of there, is there! Top notch job!

 

[vascon2196]

Those fasteners accent the engine nicely. That engine looks like it's going to scream!

 

[ttrikalin]

the brass cylinders are fantastic.

 

[cfellows]

Thanks guys, for the continued vote of confidence. Took a break from the small rotary table to get some work done on the crankshaft for my radial. Here it is, clampted into a v-block while the loctite cures (Thanks for the v-block idea, MB). Tomorrow I'll drill it out and insert a roll pin. A taper pin would be better, but I ain't got none of those nor do I have the needed reamer so a roll pin will have to suffice.

Chuck

 

[vascon2196]

This Loc-tite idea keeps the crank pin straight while curing?

Just last night I Loc-tited a crank pin into a crank disc but left it sitting flat on my toolbox.

Interesting....

 

[cfellows]

Well, I've reached a momentary impasse on this project. The build has been super smooth and I'm very pleased with the fit and finish of everything so far. Now I have a decision to make - whether to use overhead valves with push rods and rocker arms or a simple rotary valve.

The overhead valves with rocker arms is probably 5 times as complicated. The added parts are 3 of each, valve lifters, push rods, rocker arms, valve actuators, extra ball bearings, and rocker arm mounts. And, routing the air supply to the top of each cylinder is more complicated. The head is more complicated also. On the positive side, there would be little to no air leakage between "firings" and visually, the engine would be much more realistic (and appealing).

A rotary valve, much like I used on my Opposed 4, is way simpler and the engine would look much less cluttered. But air leakage is much harder to control and there are many fewer visible moving parts which is less appealing from a model engine standpoint.

In the meantime, my shop time is stalled until I can make a decision. What to do, what to do...

Chuck

 

[jct842]

over head valves. Have seen a lot of your work Chuck so I know you can do it. I just love watching an out side valve train work. John

 

[coopertje]

Very nice build Chuck! Hope to do a radial too in future, as so many other things...... Dont mind to work, but it just cost too much of valuable hobbytime ;D

Looking forward to your progress!

Regards Jeroen

 

[rleete]

Now I have a decision to make - whether to use overhead valves with push rods and rocker arms or a simple rotary valve.

One of each?

 

[cfellows]

One of each?

Oooh, can't even imagine such a thing... but, then again...

 

[cfellows]

I've decided to go ahead with the overhead valve arrangement on this engine. It will be 4 stroke in operation and will use a combination of my slave exhaust valve and a ball inlet valve similar in operation to the Liney Halo radial. High pressure air will be presented to the top of the cylinder where it will be stopped by a ball bearing check valve. To "fire", a valve stem which is an interference fit with the ball valve will open the valve by pushing it to the side when the stem is depressed. This will admit air into the head where it will push a second ball bearing to the side, exposing a hole which leads into the cylinder. This will push the piston in a manner similar to my other slave valve engines.

So here is the first series of pictures on work done the past couple of days. Here is one of the cylinders with the valve stem hole drilled down through the top into the and a 1/8" hole drilled radially all the way through.

Here I've milled a flat on both the intake and the exhaust sides to receive the input and exhaust pipe flanges. I've also enlarged the hole to several different sized. The intake side is 7/32" so the 3/16" ball bearing is a very loose fit. This allows air to flow around the ball bearing when it is unseated by the valve stem. Then the hole is stepped down to 5/32" where it passes around the valve stem. Finally, on the other side of the valve stem, it opens up to 3/16" so the slave ball bearing is a close sliding fit.

Inlet side, showing the step down to 5/32" around the valve stem hole.

This shows the inlet side on the left and the exhaust side on the right.

I will be attempting to emulate the layout of the Anzani radial engine as close as I can, perhaps without as much detail. Here, you can see that on the rear side of the cylinders, there is a tube going up the back into an elbow at the top which leads into the cylinder head. This is the air/fuel inlet manifold.

On my engine, the high pressure air supply will go up a tube on the rear of the cylinder and into an elbow, similar (or at least as close as I can get it!) to the Anzani. So, in the next series of pictures, I am making my version of the elbow.

I'm milling all three manifolds in one piece of brass and will cut them apart later. Here I'm using a 1/4" end mill with radiused corners to cut out the sides.

Next I use corner rounding bitto round off the top edges.

And, the finished manifold before cutting in to three separate pieces.

Here they are cut apart and the holes for the tube have been drilled. There is also a hole on the bottom which will lead into the cylinder head.

And, here they are with tube soldered on, mounting holes drilled and pretty much ready to mount, well, after I pickle them and get them polished up!

I'm still figuring this thing out as I go along, so progress is a little slow.

Chuck

 

[SBWHART]

Comming along nicely Chuck.

Working on your own engine design certainly stimulates the old brain box.

Looking forward to the rest of the build

Stew