Alyn Foundry 'CHUK' Flame Gulper / Flame licker

[Chipmaster]

Last year I obtained some old castings and remnants of the plans for an Alyn Foundry 'CHUK' inverted flame gulper engine. This can still be seen on the Alyn Foundry website even though the business closed long ago http://www.alynfoundry.co.uk/ (Look at the 'Coming soon' section). The CHUK engine is similar to the Plank flame licker engine in both design and size, fortunately, a friend has a collection of flame gulper engines which includes engines made by Plank. Being able to examine his engines was very useful as I learnt how to make my engine. Having incomplete plans and no example of an inverted CHUK to refer to meant that I improvised some parts of the engine. Machining the castings were straightforward operations except for one which was rather awkward to hold. However, accuracy and a good piston to cylinder fit is essential for this type of engine, a lot of lapping was required here also much lapping of the shutter and diaphragm valves.
Unfortunately I forgot to take a photo of the set of castings before I started and I didn't do this build log as I went along because I wasn't confident it would work or whether I'd complete it in a reasonable time because of other larger model engine projects.
So here's a picture of  the finished engine then I'll follow with pictures of building it.

Andy



51 Flame Gulper engine - Alyn Foundry Inverted CHUK by Andy, on Flickr

Machining the top of the base,

1 Machining the profile of the base casting by Andy, on Flickr


Cylinder mounting flange - a diaphragm and spring will reside in here and the exhaust exits through the hole in the centre.
2 The cylinder sits on this flange . by Andy, on Flickr
Underside of the base,

3 Underside of the base by Andy, on Flickr
Bottom of the cylinder,

4 Bottom of the cylinder by Andy, on Flickr

The cylinder stayed in the four jaw chuck for machining the bore and I decided the external fins might as well be concentric for further operations down the line...
5 Boring out the cylinder by Andy, on Flickr

[Jo]

Nice Engine

Alyn didn't make many casting sets, you were lucky to get that one. Do you know of anyone with the other two in the CHUK range.

Was that Cast Iron as gritty as it looked in one of those photos?

Jo

P.S. In case people had not seen the CHUK family I have attached the Alyn Broadsheet which details all of them

[Chipmaster]

Good morning Jo,
thanks for adding the Alyn Foundry broadsheet. I haven't seen any other CHUK engines and I have been told that not many Chuks were cast and the Inverted were less than a handful, not even in double figures! Perhaps going public on MEM will encourage other Chuks to come out. I am glad that I made the engine, it didn't cost much and it feels even better when you see how much genuine Plank flame licker engines fetched in recent sales!!
As you noticed those particular castings were gritty but once that was out of the way there were no problems.

Andy
 

[Chipmaster]

Removing the cylinder from the fixed steady. This shows the top end of the cylinder machined for the fixed steady fingers


6 Removing the cylinder from the fixed steady by Andy, on Flickr


7 Cylinder sitting of the base by Andy, on Flickr

A ridge had to be machined on the bottom of the cylinder which will be lapped later on for a diaphragm valve that will seal against it. The diaphragm and its spring will fit inside the corresponding recess in the base


8 Cylinder base with a ridge by Andy, on Flickr

[Chipmaster]

Milling the port face, this surface will be lapped flat for the Shutter Valve (ex Stanley knife blade) to open and close the port.

9 Milling the inlet port face by AGB engines, on Flickr

Crankshaft support casting (couldn't think of a better title). This caused a bit of head scratching working out the best way to machine the casting to register with the top of the cylinder. I milled the central area of the casting flat and drilled it so that it could be attached to a mandrel held in a three jaw chuck.



10 Crankshaft support casting by AGB engines, on Flickr


11 Crankshaft support casting by AGB engines, on Flickr



12 Crankshaft support casting by AGB engines, on Flickr



When I was happy with the fit on the cylinder (which I could check with this set up) I went in with a small tool  to cut through the casting and separate it from the mandrel.
13 Crankshaft support casting by AGB engines, on Flickr

The tool can be seen breaking through in this picture



14 Crankshaft support casting - lathe tool just breaking through by AGB engines, on Flickr

So far so good.


15 Base, cylinder and crankshaft support. by AGB engines, on Flickr



16 Base, cylinder and crankshaft support by AGB engines, on Flickr

[Jo]

I am beginning to feel the need to make one of these. So that must be an excuse for another set of castings 

Did you finish marking up the drawings? I am assuming they are as "good" as the other Alyn Foundry drawings I have, where they do not show the dimensions of the casting only the machining needed  .

Jo

[Chipmaster]

Hi Jo,

no I just made do with them as they were, referred to my friends Plank engine and made things up as I went along.

Andy

[Chipmaster]

This is the inlet port, each end was drilled through with a 1/4" drill and the slot milled out using a 3/16" end mill.



18 Milled Intake port viewed from inside the cylinder by Andy, on Flickr

And a poor photo from the other side.

19 Milled Intake port. by Andy, on Flickr

I milled away the base until it was flush with the intake port, I thought that would help to get a burner and flame in close to the inlet port.


20 Milling the base so that it lines up with the intake port. by Andy, on Flickr

The two ball bearings that support the crankshaft would be fitted in this piece which started out as a 2" diameter cast iron bar.
21 Main bearing housing by Andy, on Flickr

Machined ready for the ball races.


24 Main bearing housing by Andy, on Flickr

Bolted together and flywheel fitted.

26 Flywheel mounted on crankshaft by Andy, on Flickr

The cylinder after a couple of hours lapping.


27 The cylinder bore after lappiing by Andy, on Flickr

[Chipmaster]

The diaphragm and piston were next. The diaphragm or flap valve specified was 0.25" shim formed into a regular octagon 40mm across the flats. As I could only obtain shim from a roll I parted off a cast iron disc 25 thou thick from the cast iron bar used to make the main bearing housing and the piston.


28 by Andy, on Flickr

Cylinder, piston and diaphragm or flap valve.

29 Cylinder, piston and diaphragm. by Andy, on Flickr

Lapping the diaphragm.

39 Lapping the cast iron diaphragm or flap valve. by Andy, on Flickr

Diaphragm / Flap valve - edges ground to a regular octagon 40mm across the flats. This seals against the lapped ridge on the base of the cylinder to maintain a vacuum on the power stroke. The valve is octagon shaped so the exhaust gas can pass around the valve as it is located in a recess.

41 Lapped cast iron diaphragm with the edges ground to an octagonal shape. by Andy, on Flickr

[Chipmaster]

Crank web, piston yoke, connecting rod and cam.
The crank web and cam were iron castings, the piston yoke and connecting rod used up stuff from my scrap box.

Drilling crank web for the crank pin.

31 Making the crank web by Andy, on Flickr

Crank web

33 Trial assembly by Andy, on Flickr

Piston yoke - machined using a slitting saw, drill and reamer whilst mounted on the toolpost.

30 Making the yoke that will hold the gudgeon pin by Andy, on Flickr

Piston yoke fitted to the piston.

35 Yoke screwed inside the piston. by Andy, on Flickr

Connecting rod.

36 Machining the connecting rod by Andy, on Flickr

Trial assembly.

37 Connecting rod fitted. by Andy, on Flickr

The profile of cast iron cam was machined by offsetting it in a four jaw chuck.

38 Machining the cam by Andy, on Flickr


40 The finished cam by Andy, on Flickr

[Jo]

That crankshaft support casting looked like fun to mount up for machining but over all the parts don't look too difficult.

Jo

[Chipmaster]

Yes that was the only awkward part, the engine is so simple it is a great pity the model wasn't more popular.
Not many more pictures of the build to post then some videos of the engine running.

Andy

[Chipmaster]

I had to improvise the cam follower, pushrod and shutter valve. I know what I made is crude but it has proved to be effective. I milled a flat on the crankshaft support casting and bolted my cam following/pushrod apparatus to it.




To control or keep the cam follower wheel in the same plane as the cam a flat on the end of the brass collar above the spring acts as a guide against the flat steel bar.

[url=https://flic.kr/p/uaCAt2]

Almost finished
[url=https://flic.kr/p/v7tFVV]

The shutter valve is a Stanley knife blade, ground to shape with a boss attached with silver solder followed by yet more lapping. Lapping was a feature of this engine build. I find playing audio books on my workshop iPod player helps relieve the tedium.

 [url=https://flic.kr/p/uPTvBh]

The lapped side of the shutter valve.
[url=https://flic.kr/p/uQ2zJ8]

I arranged the shutter valve mounting so that it floated on the end of the pushrod rather like the slide valve of a steam engine. The vacuum within the cylinder pulls the shutter against the port face so I just had to adjust and time the opening of the shutter. Here is a picture of a lashed up burner, it's a brass bar with a line of holes long enough for the flame to cover the intake port.
[url=https://flic.kr/p/v6YukL]

As the piston ascends the flame is drawn in through the inlet port, the shutter closes the port as the gas burns inside the cylinder hence atmospheric pressure pushes the piston back down the bore. Excess pressure at the end of the cycle as the piston descends is released via the lightly sprung diaphragm/flap valve across the bottom of the cylinder. I found that if pressure wasn't released via the diaphragm then it would blow past the shutter valve and tended to blow the flame out.

[Jo]

I like the use of the Stanley blade 

  You now have me looking at atmospheric engine casting sets. I noted that Polly Wobbles does a set for the Stockport engine that looks interesting  .

Looking forward to the video 

Jo

[Chipmaster]

Hi Jo, I wasn't aware of the Stockport engine so I've just looked it up in Polly Models catalogue and there is a video of one on Youtube. I'm very taken with the model, so much so that I feel drawn towards buying the kit. Now look what you've done!

i'll post the videos of my Chuk when using my pc later this afternoon.

Andy