Author Topic: Model Heinrici Engine  (Read 9001 times)

Online Jo

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Re: Model Heinrici Engine
« Reply #45 on: November 12, 2020, 03:15:13 PM »
Having checked my stores I might be ok for Cast Iron the size that that core would have been  :)

Most of the power cylinder is plain turning the same as the liner. The more interesting bits are the taper and getting the holes in the end and the two sides parallel to those holes. Once the taper is in place the only way to hold the cylinder will be through the bore on a mandrel. So I decided before turning the taper to hold the parallel side of the cylinder and drill for the two mounting screws and then mill the two flats. As an after thought I think it would be easier for someone else to drill the two holes then turn the taper before milling the two flats  ;)

I then mounted the cylinder on a mandrel and turned the taper. The centre "washers" on either end would have gotten in the way to turn the curved top edge so I mounted the cylinder (with the two flat sides) in one of Mr Silky's oversized 5C collets with end support and turned a pretty curve  ::)

The then tried it on the platform to find the platform profile and cylinder did not match so having milled a bit off the platform I am now adding a bit to either side so that it meets the profile of the cylinder, I'll finish sorting it out tomorrow   :wine1:

Jo

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Online Jo

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Re: Model Heinrici Engine
« Reply #46 on: November 14, 2020, 01:25:19 PM »
The power cylinder has been honed to provide a smooth inside surface using my delapena honing machine.

The piston was turned from a piece of 35mm diameter Cast Iron bar. The drawings implies a fairly thick skirt but my experience has shown that thinner is better. the outside of the piston has a few grooves to act as cavitation seals. The piston fit is such that it will slide down the power cylinder if both are cleaned with brake fluid but with any oil on either is sufficient for it to not slide  :) .

The piston yoke is made of a piece of its-so-hard-why-did-I-keep-it stainless. Both turning the outside and milling the slot made twirls of swarf that were rather hot  :paranoia: Surprisingly it was happy enough to be threaded with a die  :headscratch: For now I have left the thread over long so I have the option of putting a nut on the other end if there is sufficient space - if there isn't I will turn it off later.

I need to think about the remaining ali bits as I am not convinced that Ali makes a good bearing surface for the Gudgeon pin or the crankshaft. I'm off to look at that original engine  :thinking:

Jo
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Online Twizseven

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Re: Model Heinrici Engine
« Reply #47 on: November 14, 2020, 02:53:43 PM »
Jo,

Its looking good.  Not sure how you work at the speed you do.  :praise2:

Colin

Offline Alyn Foundry

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Re: Model Heinrici Engine
« Reply #48 on: November 14, 2020, 03:12:20 PM »

I need to think about the remaining ali bits as I am not convinced that Ali makes a good bearing surface for the Gudgeon pin or the crankshaft. I'm off to look at that original engine  :thinking:

Jo

Hi Jo.

Well.... The Japanese motorcycle industry changed a lot of engineering practices that we held so dear here in the UK.   ;)

Obviously a lot depends on the Aluminium Alloy but a good " polished " surface and reasonable lubrication should be fine for your engine.

Cheers Graham.

Online Jo

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Re: Model Heinrici Engine
« Reply #49 on: November 14, 2020, 03:35:37 PM »
And I have a lot of little aero engines that have Ali conrods that rely on just good lubrication  :thinking:

However how many "four hundred fours" had rattily cams, due to the lubrication needing to be better  ::)

Jo
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Offline Alyn Foundry

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Re: Model Heinrici Engine
« Reply #50 on: November 14, 2020, 03:53:08 PM »
You have a point Jo, but from my own experience back to my days spent at North Wales Motorcycles most problems were due to poor maintenance. Sadly regular oil changes weren't on the list for many owners.

Cheers Graham.

Offline Jasonb

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Re: Model Heinrici Engine
« Reply #51 on: November 14, 2020, 04:12:08 PM »
Are those Conrods not made out of 2014 (HE15) which has some copper in it to help smooth the ride. Not sure of what's in old alloy wheels :thinking:

For the short amount of running it's likely to get may not be worth the worry unless you are thinking of adding a few fan blades to keep you cool next summer :)

Online Jo

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Re: Model Heinrici Engine
« Reply #52 on: November 16, 2020, 12:32:48 PM »
The flywheel castings are too large a diameter to fit above the Power cylinder and too wide as the connecting rod will be offset too far  :Doh: If I increase the height of the A frames by leaving 8mm thick on the bottom rather than the 6.35mm shown on the drawings I can gain 3.2mm on the available Space for the flywheel. Even so the maximum diameter is going to have to be under 165mm and the flywheel casting started out at 168mm diameter.

Width wise: the central boss on the flywheel can be taken down to 19mm wide which will fit onto the available space on the crankshaft but I don't want the flywheel rubbing on the A frame so a bit of clearance will be needed. Having checked the clearances on the connecting rod so long as the flywheel is above the bottom of the A frame then the rim can be wider than shown on the drawing. The flywheels are started out at over 22mm wide but this is going to come down when I turn them smooth.

Lets see what happens..  :thinking:

Jo
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Online Jo

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Re: Model Heinrici Engine
« Reply #53 on: November 19, 2020, 04:01:04 PM »
Four holes were drilled and reamed in a piece of steel at the correct spacing to make the webs for the crank. A bit of hand filing to shape them up then a bit of loctite to join it all together to make the crankshaft. I have not added the spacers on the outside of the webs as I intend on adding that later  ::)

The crankshaft goes on top of the two A frames. Which need's a hole drilled and reamed for the crankshaft and the bottoms of the feet milled at the correct distance from the crank hole.

Now we can do the flywheels: Mounted on the outside of the three jaw the outside surface can be turned and the front face. While it is all set up the hole for the crankshaft can also be drilled and bored.

When fitted all together it is found the flywheels are: too big a diameter, too wide and look wrong  :toilet_claw:

Jo
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Online Jo

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Re: Model Heinrici Engine
« Reply #54 on: November 19, 2020, 04:08:01 PM »
After a bit of thinking and looking at the other engine I decided to reduce the flywheels to 152mm diameter so the outside rim is level with the base of the A frames and to reduce the width of the flywheels to 17.5mm as shown on the drawings.

Of course the problem now is that you cannot hold the flywheel and guarantee getting everything true unless it is dialed up on a face plate   :wallbang:  As the wheel was over width I could turn the outer diameter and the face leaving a bit to protect Mr Silky's faceplate and then wander over to Big C and hold the flywheel by the outside in his small chuck to turn the other face to take things to the correct width.

The flywheel has come down a lot in comparison with the original but it looks a bit better  :thinking: It is going to need a bit of extra weight.

Jo

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Offline Alyn Foundry

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Re: Model Heinrici Engine
« Reply #55 on: November 19, 2020, 04:32:54 PM »
They look nice Jo.   :ThumbsUp:

I notice that you've managed to loose the " gas pocket " too.

Before worrying about their weight I'd be inclined to carry on as you might be surprised how little is needed, particularly with there being two of them.

Cheers Graham.

Offline ettingtonliam

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Re: Model Heinrici Engine
« Reply #56 on: November 19, 2020, 06:36:01 PM »
Jo
I'm building the Alyn Robinson hot air engine. I've never built a hot air engine before, and was not sure what fit would be needed for the piston in the cylinder. I saw your comments above for the fit of the piston, and by far cruder methods than yours have managed to get it so that it drops under its own weight with a dry piston and cylinder, but just slides down slowly when oiled. It took me several hours to take off the last half thou or so to convert a stiff push fit into a free sliding fit!
I was disappointed to find that if I blocked the cylinder outlet at the governor end, the piston didn't stay put with the air cushion under it. Then I realised I'd drilled and tapped the piston head for the gudgeon housing---.

Online Jo

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Re: Model Heinrici Engine
« Reply #57 on: November 19, 2020, 06:57:30 PM »
Thank you Graham, I won't write the flywheels off until I have tried running the engine with them.

Hi Richard,

I saw your comments above for the fit of the piston, and by far cruder methods than yours have managed to get it so that it drops under its own weight with a dry piston and cylinder, but just slides down slowly when oiled. It took me several hours to take off the last half thou or so to convert a stiff push fit into a free sliding fit!

Yes it takes second to post about doing it but a bit longer to get the fit right  ;)

Quote
I was disappointed to find that if I blocked the cylinder outlet at the governor end, the piston didn't stay put with the air cushion under it. Then I realised I'd drilled and tapped the piston head for the gudgeon housing---.

You are not the only one who has done that  ::)

Jo
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Offline Roger B

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Re: Model Heinrici Engine
« Reply #58 on: November 20, 2020, 11:29:38 AM »
Those modified flywheels look somewhat more in keeping  :)  :ThumbsUp:  :wine1:
Best regards

Roger

Online Jo

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Re: Model Heinrici Engine
« Reply #59 on: November 22, 2020, 03:35:51 PM »
The power cylinder connecting rod was clamped flat to a jig with a 3.2mm thick packing piece under the small end. as the rod is slightly off centre I decided to take the 0.8mm and 0.5mm off the same side and then bore for the pins. The pins are a simple turning exercise but I modified the big end pin to have two washers of bronze to prevent rubbing.

the piston carrier thread had to be made shorter so it did not hit the bottom of the power cylinder and it was necessary to pilot drill through to the bottom of the power cylinder so that the piston can go up and down to allow for round and round testing shortly. To do that will require the displacer cylinder and the A frames to be bolted down  ;)

I also investigated the displacer rod that came with the set  :headscratch: the end that goes round the displacer rod is only 13mm wide where as the drawing imply it should be 16mm. I have thought about this and have a cunning plan  :naughty:

Jo



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