Building a Poppin

[b.lindsey]

Recently, a fellow modeler I met back in Oct at our annual engine show, forwarded some pictures of his progress on the Poppin engine. I found the plans and the more i looked at it the more i liked it as a smaller mate for the Phillip Duclos Flame Eater I built years ago.  I was also looking for a shorter term project to work on while working on drawings for the next big project ( a 1/4 scale build on the Wright Brothers 1903 engine).  So a search through the odds and ends box turned up most of what I needed and here is the progress after a few days.

The basic frame was roughed out at work on the full size mill, leaving all the detail work for the sherline mill at home this weekend. The first two pictures show the drilling and boring of the hole in the frame where the cylinder will mount. The last two show the frame after all machining but before and finishing work (sanding, polishing, etc.)

[b.lindsey]

For the cylinder, I had a piece of cast iron just barely long enough for the required dimensions. The next set of pictures shows the cylinder machining. After turning down the OD, the bore was drilled and  bored leaving enough stock to lap the bore. The piston will then be fit to the finished bore size of .625" give or take a few tenths. Before turning the fins with a .040" parting tool, I made a center extension out of some scrap aluminum for added support. The live center for the sherline is neither large enough for the bore nor does it extend far enough. This is shown in the second and third pictures as the fins were machined. Finally the mounting holes were drilled and tapped back on the mill with the rotary table as shown in the last picture.

[b.lindsey]

The last two pictures for now show the mounting base and the three pieces completed thus far in a trial assembly.

[zeeprogrammer]

Great start. I'll be watching.
I'm looking forward to seeing the Wright engine too.

[Bearcar1]

As am I as well. I enjoy seeing such projects being produced on the Sherline equipment. I own one but have not used it for many years now for some reason or other. Great start on what I am certain will turn out to be a fine running little engine B'.


BC1
Jim

[Jo]

That looks very interesting, I don't know the engine. But I am here to learn  and am sure I will enjoy watching your progress .

Jo

[b.lindsey]

Jo, this one  was published back in 1980 and was desiged by Dr. J.R. Senft so its been around a while in the genre of atmospheric engines.  I am making a few mods not to the overall design but am going to try using a graphite piston rather than a cast iron one.  It should improve the self lubricating properties and others have used graphite in the Philip Duclos design successfully and probably in this one as well. I  have been meaning to change over my Duclos engine piston from steel to graphite so if this works out well I will finally make that mod to it also.

Bill

[chuck foster]

another great looking engine bill 

the wright brothers engine will be very interesting as well 

chuck

[fcheslop]

Hi Bill, Ive built a couple of Poppins they are great runners and run well on graphite pistons
The only mods I did to the original design was to machine a spigot on the cylinder to locate into the frame and a split type big end with shells as it makes it a lot easier to remove the piston for cleaning and made the frame a little like a hit and Miss engine. They run even better for anyone in the U.K using Shellack thinners instead of meths
The valve on mine are 3thou thick as I found the 2thou one a little fiddly
My fave flame licker still has to be P Duclos Little Blazer
Hope you realise they are addictive and one wont be enough
Nice work
best wishes
frazer

[b.lindsey]

Frazer, thanks for the info, especially as to the graphite piston and the valve thickness. Just aboiut have the cylinder head done and may get to some of the other smaller turned parts as time permits. Will post more pictures later.

Zee, Jo, Jim and Chuck...thanks for having a look also.

Bill

[Don1966]

Bill, that is a great start and i am just getting back from vacation, so just in time. Love to follow you builts.

Don

[arnoldb]

Great start Bill !
Got my chair pulled up - the Poppin is on my to-build list as well.

Kind regards, Arnold

[Jo]

Bill,

I have just found some details of this engine, nice.

I haven't built one of these: Another engine that may need to be added to the list So many wonderful engines to build and so little time......

Jo

[b.lindsey]

I didn't get any more pictures posted last night so here are a few of just the cylinder headPhoto 1 is facing the inboard side and drilling and adding the internal countersink as per the drawings...supposedly to allow the flame to widen some as it enters the cylinder. Photo 2 shows my rather bizarre way of cutting off the piece from the stock. Though the sherline lathe is capable of parting off, it can be rougher at times especially in steel, so I use a slotting saw on the mill with the rotary table. Takes a bit longer but the consistency of the cut is better by far and since I was ending up with a piece only 1/16" thick, facing the parted off side doesn't give much material to chuck on. Photo 3 shows the saw cut finish and though it looks rougher in the photo, it was even enough that a few swipes across some emery paper and it was smooth as silk. The last photo shows it attached to the cylinder.

[90LX_Notch]

Bill-

I made mine with a cast iron piston and have never had any problems with it.  I use denatured alcohol mfg'd by Sunnyside Corporation and have never had to take mine apart to clean it.  I elected to build mine with ball bearings from Enco. http://www.use-enco.com/CGI/INSRIT?PARTPG=INSRAR2&PMAKA=327-8035&PMPXNO=22568957

There's a video of it running on my YouTube page.

-Bob