Paddleducks
Other Marine Models => Live steam => Topic started by: Turbinia on February 21, 2011, 04:36:26 AM
-
After joining Paddleducks and introducing myself kiwimodeller asked to see some images of my WADA Works Steam Turbine so here they are.
Some observations on the construction of the turbine are: the body seems to be made from brass plated pressed stainless steel, the rotor made from brass with individual aerofoil shaped fins silver soldered around the periphery, the shaft is mounted on two stainless steel shielded ball races, the shaft of the rotor has gear teeth cut directly into the end of it driving a single large diameter spur gear itself supported on two ball races, there is no provision for lubricating the geared drive.
Mounted on top of the turbine is a Forward / Reverse servo operated valve, it also can be used as a throttle control.
The boiler was originally fired by a Methylated spirit burner but I have changed to a Gas fired Cheddar burner
setup, the safety valve is set to blow at 30 psi, on full throttle the boiler can't keep up with the demand it's OK for short spurts so I have run it at half throttle which gave a good scale speed to the 40" WW2 destroyer hull that it originally powered, I'm building a similar length model of Turbinia for it's next home.
Best regards to all
-
Would a model of Turbinia at that size be big enough to hold the turbine unit and boiler? It's a very narrow hull, and would have very limited displacement to carry the weight....
Regards
Eddy
-
That's a good question, I have started on the hull, its around the same size as the WW2 Destroyer model that it originally powered, so I'm hoping that it will work.
If it doesn't have enough freeboard then it will have to be electric powered, and I'll be back to the drawing board.
Regards
-
Great to see photos of the real thing thanks, I had only seen drawings in adverts prior to this. It will be very interesting to see how it performs in the new hull. Heres hoping it is successful as you could not find a more appropriate subject to put it in. Cheers, Ian
-
I'd be interested in reading more about the performance of this turbine. How does it compare to a piston engine in terms of power / steam usage?
-
The only answer I can give is that it is probably equal in power to the Graham models TVR1A engine, thats a purely subjective comparison, this is after seeing the performance of each on the water in similar sized hulls. Yes I appreciate that there could be big differences between the hulls I observed in terms of drag, propeller size etc.
It would require some serious testing of torque, etc to give a true comparison, something I have no setup to perform.
At 20psi you cannot slow the output shaft with your fingers, but you could stop it starting to rotate as it has no torque at startup, revs are everything on a turbine, with a conventional steam engine its all about torque and not the revs.
But the thing I really love about it is, it doesn't need steam oil, so you do away with exhaust steam separators and although there is nothing to see eg. crankshafts, flywheels and conrods moving, you get a beautiful turbine whistle/whine especially if you put it into full reverse from full ahead, but once the model is a few yards away from the shoreline most people won't be able to see any engine movement anyway.
But the big downside is that its greedy on steam, a conventional piston steam engine will run much longer on a smaller boiler, so for a good days sailing, conventional beats the Turbine in Gas and Water consumption, and running duration.
Regards
-
Thanks a lot, that's what I wanted to know.
-
Today I noticed on our local internet auction (the equivalent of Ebay) a book for sale called "Model Steam Turbines - How to design and build them by H H Harrison. Has anybody read it and is it any good? Thanks, Ian.
-
....you cannot slow the output shaft with your fingers, but you could stop it starting to rotate as it has no torque at startup....
Ah, I was wondering about that eg. why I've never heard of a steam turbine railway locomotive or road vehicle...
-
There have been steam-turbine railway locos, and with direct drive. Most were unsuccessful.
I recall one UK one, but have no ready reference.
In searching, I found this excellent site which covers the lot:
www.worldlingo.com/ma/enwiki/en/Steam_turbine_locomotive
There are also links to steam-turbine locos with electric drive, which is similar to a gas turbine. That drive allows the turbine to keep working at high revolutions. I recall the French turbotrains: the ran on aviation fuel, and both sounded and smelled like an aeroplane.
Regards,
Roderick B Smith
Rail News Victoria Editor
-
interesting, I hadn't known about those.... ::)
-
Here is a video of A WADA turbine loco,
http://www.youtube.com/watch?v=G0XnCIeZR3I
and my WADA turbine and Boiler
http://www.youtube.com/watch?v=Aj7weQHMN-U