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Old 04-07-2015, 12:45 PM   #51
lohring
 
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Have you considered loading the prop by submerging it in a closed can of water? I believe Jim Bamford used this method in a simple brake dyno.


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Old 04-07-2015, 01:41 PM   #52
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Have you considered loading the prop by submerging it in a closed can of water? I believe Jim Bamford used this method in a simple brake dyno.


Lohring Miller
It has been tried in a pond but needs forced air as well to get efficient combustion.
I have a powerful leaf blower but matching air speed and prop loading needs very fine tuning.
The slightest variation on many things related to hydroplanes at 130mph upsets all the settings i.e. weight, CG, prop depth in water when running at speed, angles of skeg, engine settings and type of load on engine.
Too much load and engine plus generator can overheat.
Light load and excess fuel and water cools it all.
Matching bench tests even with a dyno to actual competition speeds and conditions is not easy.
IC engines do not have as many problems compared to high speed flash steam power plants.


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Old 04-07-2015, 03:36 PM   #53
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I obviously have a lot to learn, but that's what makes it fun. Could you explain what changes you made to your piston? I was considering a two piece aluminum with a cast iron top, but decided proven construction was a better place to start.

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Old 04-07-2015, 04:16 PM   #54
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I obviously have a lot to learn, but that's what makes it fun. Could you explain what changes you made to your piston? I was considering a two piece aluminum with a cast iron top, but decided proven construction was a better place to start.

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Dimensions of original piston is based on Bob Kirtley design after just breaking Bobs record for the following year the piston became a slipper type an increase of over 6mph with laps in the 130mph bracket.

The problem for a long running engine would be loss of lube through the uniflow exhaust ports.

I use mainly solid lubrication and get a run of about 19 100 metre laps depending on the hydroplane performance.

The 2015 slipper piston has to be tested in competition as there could be problems it is more of a design of a early F1 piston.



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Old 04-16-2015, 08:21 PM   #55
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I'm rebuilding all my damaged steam generators that because of overheating and bursts made them too short for efficient steam production.
Now having a Tig Welder decided to try to reclaim them as the stainless tube is getting expensive.
The prove of the pudding will be when they are under competition conditions with heat and pressure.
Sorry some of pictures not that clear.
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Generator welding jig.jpg   Tig welded generator.jpg   Testing rebuilt generator.jpg   2015 rebuilt generatot pressure gauge hydraulic test.jpg  
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Old 04-17-2015, 10:41 PM   #56
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I'm rebuilding all my damaged steam generators that because of overheating and bursts made them too short for efficient steam production.
Now having a Tig Welder decided to try to reclaim them as the stainless tube is getting expensive.
The prove of the pudding will be when they are under competition conditions with heat and pressure.
Sorry some of pictures not that clear.
Paul,
Do you feel that a butt joined T.I.G. weld will hold at the high temp and pressure of competition speeds.

I could only find 6m lengths of St/St tube so to get the 32ft length of coil It was tig welded but I made a sleave about 1" long and had it T.I.G. welded at both ends with the tube inserted 1/2" from both ends and never had any trouble but then I was not running at the speeds you are, I have no knowledge of what my Temps and Pressures are.

Best wishes on your quest for speed.

George.
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Old 04-17-2015, 11:36 PM   #57
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Paul,
Do you feel that a butt joined T.I.G. weld will hold at the high temp and pressure of competition speeds.

I could only find 6m lengths of St/St tube so to get the 32ft length of coil It was tig welded but I made a sleave about 1" long and had it T.I.G. welded at both ends with the tube inserted 1/2" from both ends and never had any trouble but then I was not running at the speeds you are, I have no knowledge of what my Temps and Pressures are.

Best wishes on your quest for speed.

George.
They are swaged into a top hat configuration and fuse welded into the tube outer diameter it is a test.
The 3/16 inserted into the 1/4 diameter tube was fuse welded on 3 of my original generators including the 129mph one with no problems by a race car Tig welder when using filler rod on test pieces we found inclusion into the internal diameter.
Admittedly competition will decide if OK but has been hydraulically tested to over 300 bar which is no way near the pressures of competition but heat might be the downfall?

Paul
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Old 04-18-2015, 03:16 PM   #58
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I can't find any tables for 316 stainless tubing at temperatures above 1000 degrees F. At that temperature the burst strength is about 3/4 that at room temperature. The tensile strength of 316 stainless is around 1/3 the room temperature value at 1500 degrees and 1/50 the room temperature value at 2000 degrees. I bet the tubing failures are mostly over temperature problems since the strength falls off a cliff much above 1200 degrees.

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Old 04-18-2015, 08:11 PM   #59
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Know doubt high temperatures are the downfall of the tubing if you reduce water feed the tube at a hot spot will balloon and burst.

After a pressure fault last year the 321 tubing degraded with the intense heat and when the pressure fault was rectified tubing failed with little pressure.

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Old 06-17-2015, 02:59 PM   #60
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Had the steamer out for my first meeting of 2015 at Kingsbury Water Park trying various modifications after last years trials and tribulations.
First run did 121 mph I was personally disappointed thinking the repaired steam generator was a possible culprit or the redesigned piston not up to expectations.
On inspection found the pump drive screw had worked loose it is normally locktighted but thought it was tight enough as it is awkward to adjust the stroke when locktighted.
2nd run it did 124mph but was slow accelerating if timed a few laps later 130 mph was a possibility.
Final run under bad weather it did 127.8 mph average speed on stripping the engine found the retaining pin was missing that stops the curved cam follower rotating a part that I diligently check is tight.
For July meeting will redo that pin to be fool proof the repaired steam generator that I had Tig welded (my first attempt at stainless tube Tig welding) was successful I now have a few reclaimed ones now as spares.
The shortened slipper piston was OK apart from some carbon near the ring gap at top of cylinder bore.
The next time out I will have competition from Bobs steamer which is good for development.


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