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From Plans / Re: Vince's version of the Monitor Steam Engine
« Last post by vcutajar on Today at 04:59:54 AM »
Thanks Achim.  Best of luck on your Hoglet.

Specific Engine Help / Re: Steam engine suffering from hydraulic lock
« Last post by Pete49 on Today at 03:09:25 AM »
dumb comment I know but as you bought it do you think the steam chest is upside down. It seems logical to place a drain underneath, wellto me anyhow.
From Plans / Re: How about a Rupnow Vertical Engine
« Last post by Sleddog on December 10, 2017, 11:36:14 PM »
Thanks for the comments guys...Brian, I'm from South East South Dakota.

Started on the frame. 1" holes drilled for the 1/2" radius. Located, drilled for camshaft & crankshaft. Also bored for crankshaft bearing. I drilled then reamed a .375 hole so when I flip the frame over I'll be able to indicate & bore in the correct location. After that operation is complete I'll drill to finish size as indicated on the plans.

I discovered my indicating plates are not the correct ones for my table! :o

The plates have 4 mounting holes & the table has 3!

So, I'll have to wait for the correct plates to arrive before the gear cutting gets underway. There's plenty else to keep me busy.

Thanks again,


Your Own Design / Re: Bugatti Typ 50 1/4 Scale model
« Last post by BillTodd on December 10, 2017, 09:18:29 PM »
I'll see what i can find in the scrap bin ;-)
how long are your plug insulators ?
Your Own Design / Re: Model Compressor---Maybe
« Last post by Brian Rupnow on December 10, 2017, 09:00:16 PM »
It has been a snowy miserable weekend here and good wife has a cold, so I've spent more time than usual playing in my machine shop. The compressor is taking shape and beginning to look like the 3D model. The gears do mesh, and the pistons do slide back and forth, although somewhat reluctantly. I will finish up the baseplate and the drive disc that moves the yoke back and forth tomorrow, and then a bit of 'running in' on my bench set-up to loosen things up a bit. Once I get it moving freely, I will start on the 4 valves.
Your Own Design / Re: Bugatti Typ 50 1/4 Scale model
« Last post by michelko on December 10, 2017, 08:48:54 PM »
Hi Bill,
many thanks for the kind offer. I live in germany.
If you have some pieces i would gladly take them.
Of course i will pay for the postage.

Regards Michael
From Plans / Re: How about a Rupnow Vertical Engine
« Last post by Brian Rupnow on December 10, 2017, 08:44:06 PM »
Sleddog--very nice start to the engine. I'm always glad to see an engine I designed coming to life. Where abouts are you in the world.---Brian
From Plans / Re: Hoglet, an European Version
« Last post by vcutajar on December 10, 2017, 08:28:35 PM »
the first Hoglet running as a single cylinder.

I am sure you will quickly find the reason why you lost compression on the other cylinder and it will run even better.

Chatterbox / Re: Talking Thermodynamics
« Last post by crueby on December 10, 2017, 07:56:03 PM »
The extra air inlets in an aircraft gas turbine has everything to do with cooling - as they create a boundary layer between the very hot combustion gasses and the metal of the engine. Getting the more than 1700 degree centigrade combustion gasses separated from the metal is vital for engine life  :o

The first two (or more) turbine wheels has hollow blades that are air cooled from the inside + holes for letting some of the cooling air out to form yet another boundary layer around the blades.

A certain percentage of the incoming air is use for cooling the engine parts at different locations. The first is use to cool the last compressor stages, then maybe 40% is feed to the combustion chamber for power production. The next is use to cool the outside of the chamber and enters as secondary air as cooling (some might be used to burn too). Now some is used to cool the turbine housing and stator blades.

There is more than one airflow in a modern engine :
One going through the inner parts and out through the last rotating compressor blades and out through the first rotating turbine blades.
Next layer goes through the power section and is burned.
Third layer is used to cool stator + turbine blades and combustion chamber + turbine chamber.
All modern Jet engines has a bypass fourth layer created from the big fan in the inlet - this is the main thrust and also cools the outside of the engine (not the part we see outside) - you will not see the fourth layer in a gas turbine for helicopters for instance.
Wow - thats a very different kind of 'jet' - I was referring to the tiny gas nozzle jet in the poker burner. Sounds like you have some experience with the big kind - built any working models of jet turbines?
Oddball / Re: Colibri Hummingbird Dynamic Sculpture - WIP
« Last post by kvom on December 10, 2017, 07:55:10 PM »
All the parts are looking great Kirk. Are you getting close to doing any of the sub-assemblies yet?


Many of the sub-assemblies involve gluing or otherwise hard to undo assembly.  My plan is to dry fit everything first.  to re-check vertical alignment.  There are 15 different spacers, mostly round disks with center holes needed for this purpose.  I will turn these from either aluminum or brass as I go.  I have stock being shipped that will be used for the 4 main "frames" and the long tail cam follower.  Once the frames can be put together I'll have a basis for attaching the sub-assemblies.

I'm still debating on what to use for the larger center gear.  Brass in that size is too expensive.  I may end up with Lexan or similar.

In the mean time I still have some smaller parts to machine out of the aluminum sheet I already have, not to mention more acrylic parts.
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