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[Circlip]

    OOOOH Bogstandard, wash your mouth out with battery acid! You can hardly count the likes of Prof Chaddock
     with the suck it and see brigade! The clip you have picked up illustrates exactly the need for speed and efficiency
     of turbines in that:-
                              1   You can hear the turbine slowing DESPITE the high gear reduction.
                              2   The overhung rotor is more difficult to balance - reduced RPM
                              3   Open EXHAUST - If sealed can be COMPOUNDED.
     To name but three, - in the other clips on the same vids, some of which Capricorn have been made in the land
      of the free   the one in which shows the making of an electric generator to power a 'Flash light' bulb, not
      only does it not immediately work with the as designed input system (OK thats what we're about here) BUT
      even by blasting it with high PRESSURE compressed air, you can still hear the rotor STALLING.

                             

[Capricorn]

John,

That's great your offering to build a prototype, I'd be happy to consider purchasing one.  Being from another region entirely, and not having heard the term bumph, I had to look it up "Extra periphery crap, surplus to requirements.", extraordinarily accurate.  20 years ago I might have had a clue what I was doing, now I just guess.  I'll look at the video later (takes time).  Thanks for all the input (all) it's very helpful, and an actual working turbine engine would be more than helpful.  Cap

[Capricorn]

Circlip, I'll have to listen more closely and digest.  What might be a reasonable low rpm?  15000?
Got started, you see I can just start screwing one bit on at a time and soon I'll be screwing the prop on the end.

[Circlip]

  You didn't say you were making a GAS turbine!

[Circlip]

    GAS turbine!  English joke.  Just to throw another hat in the ring (Rickenbaker)  American joke, the really high
     speed bearings are LIQUID or GAS!

[Capricorn]

The droll, dry English humor alive and well?  I don't know what you mean, whose Rickenbaker?  The propane is for the boiler silly.  Although one of my great grandparents was from England, Norwich area I think, the rest were Irish and Scotch Irish, so I can't be expected to trust you all  , heh, heh.  A gas turbine would be a little more direct wouldn't it? Cap

[Capricorn]

Hope I didn't offend anyone  .  Just to show you I'm not all full of hot air see photo (it's helium, not hot air).  It's my other 10 foot long model.  A 1:80 scale airship, 10 feet long, 20" diameter, that photo is old, had to crop it quite a bit to fit in the 256k max postable size here.  It's got the flaps, servo's, motors on now, all it needs is a lightweight reciever and gasbags. Current weight is 175 grams, add gas bags and battery, it's be close to neutral bouyancy (I hope). Cap

[bogstandard]

Based on my previous experience of pocket edge turbines (not a lot of it), I have drawn up a very basic sketch of a small turbine that should work well, and would give a compact design of about 50mm OA diameter and length.
I am just finishing off an engine at the moment, so maybe next week I might be able to knock one up for running on air.
My boiler has now finally given up the ghost, and I have no way of 'steaming' one, but if air trials show it works well, I can knock one up out of materials for running on steam, then I would require the assistance of someone with a boiler. Unless someone wishes to donate a brand new 3 1/2" vertical boiler with all the goodies attached
The nozzles will be a converging design, starting at 3mm and ending up at 1.5mm, and by using a basic steam speed control (my own totally sealed unit), proportional fwd/rev should be obtainable.
Tangential exhausts will help to 'scrape' the steam off the rotor and hopefully reduce the pressure build up in the chamber.

John

[Circlip]

    Capricorn, shame on you. (Eddie) Rickenbaker was one of your countrymen who came over to France in the
     Great War, (WW 1 ) to beat the German Air Force for us. His emblem on the side of his Nieuport was a top hat
     inside a circle. I am sure I have seen the construction and operation of a simple and muti-stage turbine similar to
     the bogstandard one on one of your sites overthere, will try to find it.

          Ian

[Circlip]

     Isn't tintrnet wonderfull?  Just Googled model steam turbines and it came up with a couple of interesting links:-
       www.archive.org/details/modelsteamturbin00harrrich    copy of harrisons book to download, - cheaper than
       nearly $90 Canadian to buy original copy.   Other site was  www.indianarog.com     

         Ian

[Capricorn]

Lost my whole post, got to write it over. 

John, I wasn't able to open the larger version of your drawings (true back of the paper napkin sketch, the best kind).  Does it have the fingernail type buckets like the other one?  50mm sounds a bit small, but you've made them before, is that a prototype or do you thing it can steam a 10 ft long 100 lbs destroyer at 8-12 knots?   I thought you all held out on metric, we still have the imperial units here, eventhough just about everything is metric (from China etc).

Circlip, Forgive me, I thought the name sounded familiar, did Eddie shoot down any zeppelins?  The internet is great, I had some time at work today for a bit, the connection is much faster there and found many many turbines, boilers etc, some very strange ones, quite the assortment.  Thanks for the links, I'll look.

Check out the tiny steam (compressed air) engines on this one, one fits on the fellows finger nail:

http://www.powerhousemuseum.com/collection/database/?irn=214818

Cap       I'm working a bit on boiler design I'll send over a sketch sometime

[Capricorn]

Wrong website, although that one is interesting, the small fingernail sized one was on a machinist web site, the machinest is from India or something and make everything on a huge old lathe.  I'll try to refind the website but here's the photo of it.

[bogstandard]

Try here, half way down the page.

http://www.prismz.com/minipower/

John

[Capricorn]

Steve, Have you seen anything related to that turbine, the picture looks a hundered years old.  I recall now the Indian machinest, Iqbal Ahmed, pretty niffty 4 cyl gas engine. 

http://www.craftsmanshipmuseum.com/Ahmed.htm

I'm still struggling with what to make the hull out of, it would be a huge project itself.  Scaleshipyard. makes a 1/48 scale fletcher hull around 7 feet long. I don't know how well it holds up to heat, but it sure would simplify building this project.  It's a bit small though, and the weight drops a lot, down to 40 lbs rather than 100.

I've done a bit of plaster casting, it appears that plaster might make a decent liner for the burner/boiler, heavy though.

Cap

[Capricorn]

Hope you're all still around!  Have done some adding and weight is more of an issue than I had expected, not too surprising I guess.  The plaster liner adds a lot of weight.  Had to shink a few items down a bit, dropped one propane tank and one motor, and it won't be carrying a car battery.  Still in preliminary stages but I now have a better idea of the weight issures.

Also had to make the decision to make the hull out of wood, did not want to but it's more likely for me to build, and it's light in comparison.  I'll cover it with fiberglass.  All the wood will have to be sealed up and probably encased in some sort of resin.

So is what type of vertical boiler are we looking at for your turbine John? What are the goodies?

Cap

[bogstandard]

Hi Cap,
When a post starts to get sidetracked away from the main original subject I tend to ignore it for a time until it gets back on track.
Unfortunately another main project has reared its ugly head in the workshop, so for about another two weeks that will now be taking priority. So when this post is on about steam turbines again rather than how small a chaps engines are, I will pick it up again.
John

[Martin (Admin)]

There are some interesting video on www.youtube.com if you do a search for steam turbine ..... 

[Circlip]

      Only two small observations Capricorn,  It doesn't matter whether you are using 'Normal' or Flash steam, why
        are you determined to use a vertical boiler? and why are you thinking of using PLASTER as an insulant?
        With a HORIZONTAL boiler the CofG is lowered, and the modern insulators, EXCLUDING Asbestos are akin to
        what NASA keeps chucking into space - CERAMICS, - no not porcelain's but ceramic papers, about 3mm SORRY
         1/8th of an inch thick, so you can multi layer.

                  Ian

[Capricorn]

Sorry John, didn't mean to get off the subject.  I'll try to draw a version of your engine and see how close I come, then you can look at it and tell me if it's close.  Cap

Thanks First Sea Lord I'll take a look on another computer this one is not good for viewing videos, I know there are a lot out there.  I'm just trying to zero in on a good turbine engine, so it'll take some time, but sounds like John is quite the engine builder, what's the point in torturing myself if I can get one from him?

Ian, I think the one I'm planning is a horizontal boiler, John wants a vertical boiler.  I'll look into the ceramic paper, it sounds expensive.  But now that you mention it, with weight being a bigger issue than I thought it's probably worth looking at other material.  I just figured I'm going to try to throw as much flame as I can in to it and I'd like for it not to glow orange.  Plus the plaster casting is simple and buildable for me, but I'll look some more.  Thanks  Cap

[bogstandard]

Cap,
If you read my post about the boiler, I was in fact joking. My boiler is now defunkt, and I jokingly asked if anyone was willing to give me a new one.
You should be considering if at all possible a horizontal, maybe with a ceramic burner, these are a lot more efficient. A flash boiler would be ideal but I have no idea who is producing them. There is one drawback with a flash boiler in that it has to have a pump to supply water. The way they work is unlike a normal boiler which is basically a tank full of hot water being kept hot by the burner to produce steam, a flash boiler only has a small amount injected which instantly turns to superheated high pressure steam, and is usually in sync with the engine so when the engine speeds up so does the flow of water. A good example is if you have a pan full of water on the stove and you are waiting for it to boil - a normal boiler, if there is no water in the pan and you dribble a little bit in slowly, instant continuous steam - flash boiler.
As I said in my previous post I am just designing and making a new type of air operated engine, so it will be a couple of weeks until I can concentrate on something else.

John

[Capricorn]

I see, I thought maybe you wanted to get a boiler for a turbine engine.  I'm slightly familiar with the flash boilers, understand the principle, and was thinking about it but it seemed a bit tough to make.  In any case I always intended for it to be horizontal.  I'll also look at ceramic burners too, I've seen a few but obviously aren't very familiar with them.  Hope your other engine goes well.  Cap

[Capricorn]

Have made some progress on hull.  How's that turbine engine coming John?  Just kidding, it would be great if you had time but I'll plod along and get something in there eventually.  Cap

[Capricorn]

A bit more progress.  Still hoping to use a steam turbine, but it's tempting to go ahead with some scooter motors. 

[andrewh]

Capricorn, Hi

I was just gathering information to pass to you on RCGroups and here you be!

Strong suggestion - don't go for heavy insulation, in fact don't worry too much about it!  There are a lot of balsa steamboats with sinple light insulation.
You can use litho plate - bend up a U shaped piece long enough to cover the boiler/burner - you can make it the chassis for the whole sream plant so that it lifts out for lighting, service, cursing at.
Plumbers use carbon cloth for insulation when soldering pipes close to wood or combustibles - this is abourt 1/8 thich and light and flexible - line the hull with one
My favourite (we have a u in Favourite here) is aluminium  (we have an i in aluminium too) cooking foil - lay 3 or 4 layers together, put it in place and crimp the edges  -
viola!  lightweight insulation

andrew
still going to look in the loft!

[Capricorn]

Thanks Andrew!  Those are great tips, I guess I should figure that out when I see the boilers with real wood slats around them, thats a great tip.  I'm glad you reminded me, earlier in this string cvabishop mentioned an article, it was in modelboats uk 2007, and he copied it and emailed it to me, I'd nearly forgot about it.  If that's the one you can postpone your trip to the loft, or I can email it to you as well if you're not sure or want to see it anyway.

I take it you work with live steam, I really have to take some time and look at others work, I imagine you've got some I'll look for them too.

Pops directed me here a while back and I've gotten a lot of good input, advice etc, I haven't done much regarding the turbine for a while though, must get back at it, the time for it is approaching.

Cap  (Joe Cain)