Author Topic: Radial Engine Update  (Read 8990 times)

Offline cfellows

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Radial Engine Update
« on: August 23, 2014, 07:36:56 PM »
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
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Offline b.lindsey

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Re: Radial Engine Update
« Reply #1 on: August 23, 2014, 07:44:57 PM »
The new heads sure look nice Chuck. Looking forward to seeing how it all turns out.

Bill

Offline cfellows

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Re: Radial Engine Update
« Reply #2 on: August 25, 2014, 01:38:43 AM »
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
So many projects, so little time...

Offline Jo

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Re: Radial Engine Update
« Reply #3 on: August 25, 2014, 07:35:31 AM »
Hi Chuck, those are looking much more Anzani like  8)

Jo
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Offline cfellows

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Re: Radial Engine Update
« Reply #4 on: August 25, 2014, 03:02:58 PM »
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
So many projects, so little time...

Offline cfellows

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Re: Radial Engine Update
« Reply #5 on: August 31, 2014, 08:40:37 PM »
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
So many projects, so little time...

Offline cfellows

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Re: Radial Engine Update
« Reply #6 on: September 01, 2014, 08:20:00 PM »
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
So many projects, so little time...

Offline cfellows

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Re: Radial Engine Update
« Reply #7 on: September 01, 2014, 10:36:27 PM »
So I finished cutting 24 teeth in each gear.  Next I'll cut the cam profile.



Chuck
So many projects, so little time...

Offline stevehuckss396

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Re: Radial Engine Update
« Reply #8 on: September 01, 2014, 10:59:39 PM »
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.
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Offline b.lindsey

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Re: Radial Engine Update
« Reply #9 on: September 02, 2014, 12:20:27 AM »
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

Offline cfellows

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Re: Radial Engine Update
« Reply #10 on: September 03, 2014, 09:57:01 PM »
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
So many projects, so little time...

Offline cfellows

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Re: Radial Engine Update
« Reply #11 on: September 03, 2014, 10:01:23 PM »
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
So many projects, so little time...

Offline cfellows

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Re: Radial Engine Update
« Reply #12 on: September 03, 2014, 10:03:48 PM »
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
So many projects, so little time...

Online sco

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Re: Radial Engine Update
« Reply #13 on: September 03, 2014, 10:24:01 PM »
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.
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Offline cfellows

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Re: Radial Engine Update
« Reply #14 on: September 04, 2014, 05:10:16 AM »
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
So many projects, so little time...