Radial Engine Update

[cfellows]

Several years ago I built a 3 cylinder radial engine which I optimistically called a stylized Anzani.



As anyone could see, the result turned out to be very un-Anzani like in appearance, having only its 3 cylinders and radial configuration in common.  So, A few weeks ago I decided to make the engine visually more interesting and add some characteristics of the Anzani, even if the result turns out to be a somewhat distant cousin.

First, I chopped off the integrated heads and tapered the fins...



Next I designed some new, separate heads and used my CNC mill/drill to cut them out of 1.125" round brass.



The original engine used the ball bearing valve configuration found on the Liney Halo Radial.  I decided to use my own poppet valve design, so made separate valve cages which will be loctited or soldered into the heads.



I've yet to cut the remaining intake and exhaust passages in the head.  Each head will be held in place with 3/32" vertical studs running down each side and into the base of the cylinder, resembling the full size Anzani.  I plan to use the original rocker arms and mount assemblies along with the original intake plumbing.

Chuck

[b.lindsey]

The new heads sure look nice Chuck. Looking forward to seeing how it all turns out.

Bill

[cfellows]

Thanks, Bill.  CNC has given me a whole new set of options on shaping metal.  Really enjoying it!

Today I made the studs and nuts which will hold the heads on. 





The studs are made from 3/32" drill rod and the nuts are made from 5/32" hex rod.  I also cut the grooves down each side of the cylinders for the stud clearance.

Chuck

[Jo]

Hi Chuck, those are looking much more Anzani like 

Jo

[cfellows]

Thanks, Jo.  I wanted to turn down the cylinder base flanges and screw the studs directly into the crankcase, but unfortunately I originally made the crankcase openings too large. 

Chuck

[cfellows]

I've been stalled for several weeks on the new cylinder head design, particularly the valve and airflow configuration.  Supplying an overhead valve engine with compressed air is not particularly intuitive. 

Here is a drawing of what I wound up with:



The valve cage was made separately and soldered into a 1/4" hole that goes all the way through the head.  The valve is then inserted into the cage from the bottom.  The spring, and keeper are held in place by an E-Clip.  The problem is that the hole that received the valve cage needs to be sealed on the bottom since this is where the high pressure air is admitted from the intake on the side of the head.  After trying many different approaches, I finally settled on a thin disk that will sit between the cylinder and the head, held in place by the two studs that hold the head onto the cylinder.  Here is a photo of all the different parts:



As a frame of reference, the valve heads are 3/16" diameter and the stems are 3/32" diameter.  The small hole in the disk lines up with the smaller hole in the head.  This is what admits air into the cylinder.  The ball valve is normally held to the right when the intake valve is closed.  This lets air from the cylinder port flow out the exhaust port.  When the inlet valve opens, the high pressure air pushes the ball valve to the left, closing off the exhaust port and letting the high pressure air enter the cylinder and push the piston down.

Here are some pictures of the engine partially assembled.









Hopefully things will go a little faster now.  I haven't settled on the cam arrangement yet.  The original engine used a 2 lobed cam running at 1/4 the crankshaft speed.  I will either use that arrangemet, or I may make 3 separate cams and cam gears, one set for each cylinder driven by the single pinion on the crankshaft.

Chuck

[cfellows]

I've decided to go with individual timing gears/cams for each cylinder.  Here are the cast iron blanks I turned down this morning. 



This is the mandrel set up I'll use to hold the blank while cutting the gear teeth and also when cutting the cam profile.



And here is the first blank mounted on the 5/8" OD mandrel.



Chuck

[cfellows]

So I finished cutting 24 teeth in each gear.  Next I'll cut the cam profile.



Chuck

[stevehuckss396]

So I finished cutting 24 teeth in each gear.  Next I'll cut the cam profile.

Nice job Chuck!  I need to learn to cut gears some day soon.

[b.lindsey]

Chuck, this is quite an impressive facelift for the radial. The separate cam gears should make a nice focal point too with the engine running. I had to stare at the diagram for the valve arrangement for a while before it finally dawned on me how it will work...the diagram is great, its my brain that wasn't in gear

Bill

[cfellows]

So I finished cutting 24 teeth in each gear.  Next I'll cut the cam profile.

Nice job Chuck!  I need to learn to cut gears some day soon.

Thanks, Steve. With all the great stuff you've built I'm really surprised you haven't gotten in to gear making.  I use commercial involute cutters and used to use a manual dividing head.  Now I use a 4th axis setup with Mach3 and wrote my own g-code so it's just a matter of getting everything setup, press start, and stand back and watch the CNC mill do all the work.  Very fast and a lot less prone to error.

It really does expand your horizons when you can custom make your own gears.  Now all I have to do is learn how to make my own gear cutters, like Don and some of the others have done!

Chuck

[cfellows]

Chuck, this is quite an impressive facelift for the radial. The separate cam gears should make a nice focal point too with the engine running. I had to stare at the diagram for the valve arrangement for a while before it finally dawned on me how it will work...the diagram is great, its my brain that wasn't in gear

Bill

Thanks, Bill.  Been moving kind of slow.  Combination of summer heat, advancing age, and a bunch of niggling design problems to overcome.  I've also been busy selling off some of my tools that I don't ever seem to use, make room for some things that will get more use!

I still feel like there's lots of room for improvement with my compressed air slave valve arrangement.  But, I've been noodling around with this thing for the better part of 7 years and haven't come up with ideal arrangement yet... maybe some day.

Chuck

[cfellows]

Some more time out in the shop today.  I got the cam/gears done. 





Now I need to make the shafts for the cams to ride on and the lifters.  That should put me well on the road to completion.

Chuck

[sco]

How did you machine the cams Chuck?

Interesting project btw - I can see the family resemblance in that exhaust ball valve with the Cirrus V8 ;-)

Simon.

[cfellows]

How did you machine the cams Chuck?

Interesting project btw - I can see the family resemblance in that exhaust ball valve with the Cirrus V8 ;-)

Simon.

Thanks, Simon.  I fixed each cam/gear on the mandrel pictured earlier, then mounted the mandrell in my rotary table on the milling machine.  I used a plunge cut with a boring head, making inside cuts, to sweep around the cam blank removing material only from one side.  After each plunge, I rotated the rotary table 1/72 turn, then plunged again.  Eventually I wound up with the cam lobe as the only material left.

Yeah, the slave ball valve is pretty much the same on all my compressed air engines.  The only real difference is with the input valve configuration.

Chuck

Chuck

[cfellows]

Progress is a little slow.  Mid September and temperatures here in Austin are still approaching 100 degrees by mid afternoon.  I have air conditioning in the Shop (garage), but it takes a little while to cool it down and the wife has an annoying habit of coming home and pulling her (very) hot car into the garage.  That pretty much takes the temperature back up to 90+ for another couple of hours. 

So I did some slight modification to the back part of the crankcase and made the valve lifters today. 



Here's some shots with the engine partially assembled.









Gettin' close to the finish line.  Now I get to start worrying about whether or not it's going to run... 

Chuck

[Don1966]

Progress is a little slow.  Mid September and temperatures here in Austin are still approaching 100 degrees by mid afternoon.

Gettin' close to the finish line.  Now I get to start worrying about whether or not it's going to run... 

Chuck

I can relate to the temperature affecting work Chuck, we have the same problem here.
 Now you really don't want me to believe that your worrying whether it runs  or not. Of coarse it's going to run I have all the faith in the world in you bud. Nice work by the way. I like....................

 
Don

[cfellows]

Got the engine running today.  Sure sounds good...

<a href="https://www.youtube.com/watch?v=k_KnmUZKRFg" target="_blank">http://www.youtube.com/watch?v=k_KnmUZKRFg</a>

Still need to do some tuning.  I think it needs stronger inlet valve springs and I may have to make new rocker arms for it.  These don't quite extend over the valve stem as far as I'd like.  I probably also need to tweak the timing.

Chuck

[Johnmcc69]

Very nice Chuck! A smooth runner, & yes, great sounding!

 John

[tvoght]

It really does sound great. I love the classic look. It's bigger than I thought.

--Tim

[Kim]

Nice rebuild Chuck, it looks and sounds great!
Thanks for sharing your video with us.
Congratulations on another runner!
Kim

[smfr]

That has a nice "quack" to it! I like it! 

Simon

[sco]

Chuck that's brilliant - love it!

Do you think John could be persuaded to do a cad model ;-)

Simon.

[Jo]

 

Now I want to go play with my Anzani castings 

Jo

[b.lindsey]

Wonderful result Chuck. I love the sound too!!

Bill

[vcutajar]

Very well done Chuck.  I like. 

Vince

[BronxFigs]

Hello Chuck-

Reading through all your threads always teaches me and shows me mechanisms that I would never have conceived.  The latest slave air-valving arrangement that's shown in this thread is a perfect example.

Your comments in reply # 11 has raised a few questions.  I noted that in the last few sentences you speculated that with a little tweaking, and improvement, that you will eventually come up with a slave-valve design to your liking.  Over the years, you have designed and then shared/posted many diagrams of your ingenious air-valve arrangements.  Can you provide any insight as to just which design comes closest to your ideal arrangement?  You have to be pleased with at least one or two of your arrangements, and displeased with others.  I, along with some other modelers, would like to know just why one valving arrangement works "better" than another.  Is it a sealing/leaking problem, spring-tension problems, etc?

Wishful thinking:....I know this is too much to ask, but it would be wonderful, and very informative if you compiled all of the diagrams, your repertoire of slave-valves and component arrangements, in a single thread and critiqued each of your valve designs,  noting the good and bad features of each design.  Your latest version of valving that's shown in this thread, with the one-hole disc interposed between the head and cylinder, looks like it could be adapted to many other compressed-air engine configurations....I think.  I could envision your cylinder assembly, and head/valving set-up, being used to build a number of different Comp-Air engines, e.g. Inline 3/4/6 cylinder "Aero"-style engines, etc.

Once again, many, many, thank-yous for sharing, and for the inspiration.  Your threads never fail to provide new, and valuable information.  Wish a few of my shop teachers were like you, and to this day, still wish you were my neighbor. : ))


Frank

[ShopShoe]

Great engine and great video. Love the sound, too. There's something about the sound of radials......

I have stolen borrowed used some of your valve ideas on some air-powered projects (that I haven't posted). I really like your valves and I would second the request to keep the information about them coming.

Thank you with respect,

--ShopShoe

[Don1966]

You see Chuck I had no doubt. Man, it sound just like a desiel engine, just awesome bud. I like.............

Don

[Roger B]

Excellent Chuck    It sounds so much like an IC engine 

[fumopuc]

Hi Chuck, I like it, the sound is really great.

[Brass_Machine]

Wow chuck, that is just fantastic. It really does sound good. Plus it has that "look" that just looks right.

Eric

[Maryak]

Wow chuck, that is just fantastic. It really does sound good. Plus it has that "look" that just looks right.

Eric

Me 2.

Best Regards
Bob