Author Topic: Model Heinrici Engine  (Read 10226 times)

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 14843
  • Hampshire, england.
Model Heinrici Engine
« on: October 29, 2020, 11:42:57 AM »
Last year as a Christmas present I was given a rather nice set of Heinrici castings to fondle and then return to their custodian  :pinkelephant: . As I have been under the weather for the last couple of months and struggling to think straight Surus thought that I needed a bit of encouragement so has let me have the castings back for a short while before he expects them to be returned as a completed engine ...


For those of you who were following along last year you will know that I am the custodian of Mr Westbury's air cooled prototype of this model: http://www.modelenginemaker.com/index.php/topic,9446.0.html  During that restoration the castings for this engine arrived although I was originally  told a Porkie by Surus about what they were  Graham quickly correctly identified them as a set of Andy Spooner's Heinrici castings for which he would be the supplier as he has the patterns.

The other supplier of the Heinrici Castings is Reeves who supply castings from the earlier version of the Westbury Heinrici design and Chipmaster has one of these models mounted on his own base.



A bit of gentle casting fettling is probably not a bad idea to help me get back into the workshop  so lets start with the base... However I keep wondering if Surus has an ulterior motive in letting me have these castings as he has confirmed that the space vacated by the Heinirici castings should be just about big enough  :noidea:

Jo
« Last Edit: November 08, 2020, 09:15:04 PM by Jo »
Enjoyment is more important than achievement.

Offline Admiral_dk

  • Full Member
  • *****
  • Posts: 3017
  • S°ften - Denmark
Re: Model Henirici Engine
« Reply #1 on: October 29, 2020, 12:30:38 PM »
I hope you have a great time working on this engine Jo - looking forward to progress  :cheers:

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 14843
  • Hampshire, england.
Re: Model Henirici Engine
« Reply #2 on: October 29, 2020, 02:27:23 PM »
Thanks Per  :)

The base casting is the first challenge on this engine. It represents a very expensive casting as I seem to recall Graham said it needed 3 cores to cast it. As proven on my re-build of the original engine an alternative is to make the base out of bar stock. If this was done it would reduce the cost of this casting set greatly.

This is a very difficult casting to hold but thankfully there is very little machining needed. First up I needed to get the base flat: It is not a good idea to try clamping it upside down on the milling table to mill the bottoms of the feet as there will be too much flex  :paranoia: Instead I worked out which two feet were 'long' and used a feeler gauge under the other two feet to find I only needed to remove 0.8mm. With the two high feet marked up with black ink they were rubbed on a surface plate to show up the high points and the offending areas where the ink had been removed hand filled down a bit. Blacken, check on the surface plate, file and repeated until the base sat flat.

The next thing I should mention is this is a very tall casting and it just fitted on Tgs table with enough spare head room to use our big facing cutter on it. The hole in the top of the casting had already been bored so I accepted its placement (which I later found was not central  :facepalm2: ) and used it to position the four bolting down bolts. The original drawings do not show the base and you may think " I know I will use a nut and bolt to hold the  engine down that will be much easier so it needs to be clearance size but Stop, stop, stop, lets first look underneath the base casting - Yes there is a nasty tapered surface under there so the fastening down will have to be either by studs and nuts, or with bolts threading into the base . The drawings show the holes as 1/4" which really dates from the original 1940's design for 1/4 Whit bolts with huge heads. I have chosen to drill 4.1mm and tap the holes 2BA which is more than adequate and it means the bolts will have smaller heads  ;)

A quick prime and it is looking base like and that is about all I can cope with for now  :-[

Jo
Enjoyment is more important than achievement.

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 1505
  • North Wales, Great Britain.
Re: Model Henirici Engine
« Reply #3 on: October 29, 2020, 03:26:36 PM »
Hi Jo.

I'll be following along with interest, although I have the patterns an engine was never built here.

A slight correction to your post....

The base had two cores. A very large one that used the inside of the pattern itself as a corebox and a second smaller one for the chimney exhaust. The problem was that it needed 3 moulding boxes to cast. The " intermediate " box, between Cope and Drag had to be made to match the height of the base pattern.

I guess you've noticed the R.L.E. flywheels??

Cheers Graham.

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 14843
  • Hampshire, england.
Re: Model Henirici Engine
« Reply #4 on: October 29, 2020, 03:32:41 PM »
Thanks for the correction Graham  :)

Yes I had noticed the RLE flywheels: I need to work out what to do with them, they both will need modifying: one needs a crank and the other the pulley  :thinking:

Jo
Enjoyment is more important than achievement.

Offline Jasonb

  • Full Member
  • *****
  • Posts: 8635
  • Surrey, UK
Re: Model Henirici Engine
« Reply #5 on: October 29, 2020, 03:36:02 PM »
Are your flywheels aluminium Jo? They look to be the same coloure as the rest of the castings with no sign of a special coating though I suppose a bit of zinc could have been added to the mix.

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 14843
  • Hampshire, england.
Re: Model Henirici Engine
« Reply #6 on: October 29, 2020, 03:38:52 PM »
Yes they are standard home cast Aluminium which means it is what every was available at the time but the base seems to machine ok so who every cast them knew what they were doing.

Jo
Enjoyment is more important than achievement.

Offline Dave Otto

  • Full Member
  • *****
  • Posts: 4343
  • Boise, Idaho USA
    • Photo Bucket
Re: Model Henirici Engine
« Reply #7 on: October 29, 2020, 03:55:33 PM »
Hi Jo

Always good to see another hot air project, I will be following along.

Dave

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 14843
  • Hampshire, england.
Re: Model Henirici Engine
« Reply #8 on: October 29, 2020, 04:25:31 PM »
Thanks Dave,

Yes the Stirling engines are always a nice easy model engine to make. This one is a good size so there is nothing small and fiddly to confuse me  ::)

Jo
Enjoyment is more important than achievement.

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 14843
  • Hampshire, england.
Re: Model Henirici Engine
« Reply #9 on: November 05, 2020, 04:23:38 PM »
The platform has had its top and bottom faces skimmed flat and taken to 11mm thick.

Using a point in the collet to approximate the locations of edges the DRO was set to put the centre of the bore in an appropriate place on the casting and this is now the datum for all the other measurements.

The mounting holes, the vertical hole for the air and a feature was added, before using a boring head to take the main hole out to 50.8mm.

To remove the feature a small plug was made and loctited in and once painted no one will ever know   :-X

Jo
Enjoyment is more important than achievement.

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 14843
  • Hampshire, england.
Re: Model Henirici Engine
« Reply #10 on: November 08, 2020, 02:51:13 PM »
The casting set came with an Alloy power cylinder, which will need a liner. It also seems to be designed to screw into the base rather than use the two holes I have already drilled in the platform  ::) . As the Cast Iron I have from which I could make the liner is big enough to make the power cylinder in one I may as well make one from solid.

While I had the power hacksaw going I also cut off a piece to make the liner for the cylinder jacket.

The cylinder jacket is a big aluminium casting which had a couple of sprue marks on it which were easily machined/filed off ready to enable the top and bottom to be machined flat. Because of the nature of casting both of these surfaces were domed so it was necessary to use the side of the casting to square up the top. Because I do not want to machine the sides flat but keep their natural cast look a couple of business cards were added between the vice jaws and the casting - these both aid the holding of the casting and prevent any marks from the vice  ;) Both the top and bottom surfaces were taken down the same amount so that the casting walls are the same thickness.

Having centred up the casting ready for the boring bit brain fade set in  :disappointed: so I will leave it there for now before I go wrong  :-\

Jo
Enjoyment is more important than achievement.

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 1505
  • North Wales, Great Britain.
Re: Model Henirici Engine
« Reply #11 on: November 08, 2020, 04:18:31 PM »
Hi Jo.

Good to see you making some " swarf " again!

When Andy first built this engine he was working for an Automotive supplier and also had access to secondhand parts.

His suggestion to me at the time was to use a telescopic shock absorber for the hot and cold end of the displacer cylinder and also suggested the use of an empty deodorant spray canister as the displacer piston.

By cutting the top off the shock absorber/damper and gently removing the bottom eye he then screw cut a thread on the upper, open end of the hollow tube that screwed into the water jacket casting that you now have in the vice of your milling machine.

I'm just relaying some information for your interest because as we all know there's many a way to get to the destination.

Cheers Graham.

Offline Jo

  • Administrator
  • Full Member
  • *****
  • Posts: 14843
  • Hampshire, england.
Re: Model Henirici Engine
« Reply #12 on: November 08, 2020, 04:27:01 PM »
Thank you Graham,

I am not sure if I would want to cut the top off of a spray can  :paranoia:   Hydraulic tubes can be very useful when making model so I appreciate Andy recycling those  :ThumbsUp: I have a piece of tube for making the displacer and brought a piece of stainless exhaust repair section for the hot end.

The aluminium castings are very nice to machine I suspect Andy may have been using old alloy wheels to supply his metal for casting.

Jo
Enjoyment is more important than achievement.

Offline Alyn Foundry

  • Full Member
  • ****
  • Posts: 1505
  • North Wales, Great Britain.
Re: Model Henirici Engine
« Reply #13 on: November 08, 2020, 06:27:37 PM »
Hi Jo.

I wasn't suggesting you go hacking at an aerosol can under pressure but use a properly emptied one. What Andy did was to then drill out the little plastic valve in the top and Epoxy resin the Brass displacer rod in place whilst being held vertically. Using this method made for an extremely lightweight displacer piston.  ;)

I wouldn't know what Aluminium he was using at the time but your guess is quite possible. I've suddenly realised I'm remembering dialogue from over 30 years ago too. Andy was a serious collector of hot air engines I'm pretty sure the engine you're building would have been directly scaled from an Hienrici in his collection.

Cheers Graham.

Offline Dave Otto

  • Full Member
  • *****
  • Posts: 4343
  • Boise, Idaho USA
    • Photo Bucket
Re: Model Henirici Engine
« Reply #14 on: November 08, 2020, 06:54:36 PM »

I've suddenly realised I'm remembering dialogue from over 30 years ago too. Andy was a serious collector of hot air engines I'm pretty sure the engine you're building would have been directly scaled from an Hienrici in his collection.

Cheers Graham.

Something that I have wondered about, on this engine that Jo is building and the Westbury Heinrici engine that I have castings for. Are these replicas/ models of an actual engine or just someones interpretation? It seems that all the photos you find the Heinrici engines are all beta configuration except for only the smallest one which is alpha? also these engines all seem to have a round water jacket instead of the square one, like on Jo's engine and also the Westbury engine.

Just wondering if anyone had some insight on these differences?

Dave
« Last Edit: November 08, 2020, 07:46:56 PM by Dave Otto »