OK PD's........ .....RGY.........I posted a note to kiwimodeller last night.............you may not have seen it yet  ....but I think your thoughts were in parallel 

The kitchen aluminium foil makes a great model version of the galvanized tinplate covers on the steam lagging    ..........

All looking good RGY...........Derek .........

No I hadn't seen your post Derek. But I am not claiming the idea, I saw it in Model Boats magazine. It is a good one. There is string under neath of course.  Geoff

Sorry I will not make the Big day on the 4th. First one daughter wanted to get married on the 3rd, got over that one. Now another daughter has given me a trip on a Bristol pilot cutter for my birthday !!! From Brixham to Southampton 5days on the 4th to the 8th. What could I say.
On top of that the Duke has yet to see the water.
I still have one model cutter (Hilda No 2 Bristol with my trawler.) Having sold Cariad No 19 Newport.  Geoff

    Back to the Duke at last. Having a bit of trouble with my ticker of late, that is the reason for the delay.
    As can be seen on the youtube video, the boiler and engine work OK.  Unfortunately I cant get the water feed to work reliably. When I designed the boiler the one and a half bar-liter rule was in force. So the total capacity was kept just below .5 liter, including the steam space. A reliable feed is essential, only six minutes safe running time without a feed.  Now the rule is three bar-liter, I have designed a new boiler with over .75 liter capacity, should give at least 10min running before hand pumping if the feed fails. I have attached the plan, hopefully? Geoff p.s. to see it you may need the excellent free down load drafting program Draft Sight.

This may be better.Geoff

Hi PD's ...& good to see you back posting  ...RGY   ...but when I open the attachment...I get   & ...millions of images ......but not from you....

Good to hear that the ticker is back in track........ ......my receipe is OZ grown garlic & red wine.........

Please keep us informed with text & images of the Duke.........remember we are still watching .....Derek  .....

Derek, glad your still watching. I have been watching to but nothing to post. The wine YES,  but vampires don't like garlic.
Geoff

I was asked for more details of the engine last year, I have just done a small mod. So took photos while apart. First the cylinder block. 22mm brass hexagon bar bored 12mm, piston bronze, 1/8th silver steel rod, end cap bolts 10 BA. The mod was cut the side of the big end, so the crank bearing could be increased in width. There had been excessive wear. Next the new bearings and crank refitted. next side view of standard at crank end.
next the ports & pivot pin, note the relief around the pin. The standard at reverser come throttle end. the reverser made from 2 pieces of 1/16th plate, cut the passages in 1 then solder together, the second piece incorporates the control arm. Finally the strap self explanatory but I have not seen one like it, but no doubt it has been done before. R.G.Y.

Well the Duke has had 3 outings on a private pond, sorry can't film and sail at the same time. She is not ready for a public performance yet . Now in bits in the work shop for mods, as the burner keeps going out . Changing to a ceramic burner which will need a new case for the boiler. I am also going to reduce the amount of metal in the engine and add insulation, To reduce condensation. GEOFF

I am surprised no one commented on the boiler design, like too many joints!!
Any way I have remove a lot of metal from the engine standard. Also half of the port plates (on side of cylinders) reduced thickness of crank to compensate. Will fill the groves with wood and cover the cylinders next. Had a pin hole in steam pipe so replaced that. Geoff

Geoff,
I think i might have said similar in the past...  I'm not steam literate ...

My Dad, sure he could pass comment, but i can't do much more than stand back and admire!

Carry on Sir, until someone more qualified Say's otherwise!

Regards,
Kim

Quote from: R.G.Y. on February 03, 2012, 05:17:47 AM
I am surprised no one commented on the boiler design, like too many joints!!
Any way I have remove a lot of metal from the engine standard. Also half of the port plates (on side of cylinders) reduced thickness of crank to compensate. Will fill the groves with wood and cover the cylinders next. Had a pin hole in steam pipe so replaced that. Geoff

Hi Geoff,
I had looked at your boiler design and did shutter at the number of joints. I made a mental note to watch and see how you constructed it. I once built a boiler that was described as weighing five pound four of which was silver solder, the important thing is always is it a safe design and will it pass a hydro and steam test.
Regards,
Gerald.

Well Kim I am far from qualified, just read the books.
Gerald, I have redesigned a square mark2 version with less cross tubes we shall see. My last boiler was from domestic water pipe!! Hands held up in horror at the model engineering club. The thickness of this pipe is .047"or 1.123mm . But I had calculated that it would stand 200psi with a safety factor of 8 times that before failure. This is why only 1" pipe is used, circumference 3" inside pipe, 3 times 30lbs = 90lbs. No problem as I only use 25lbs any way. But 4" pipe circumference 12" = 360lbs @30psi. Every force has an equal and opposite force so the force is halved I think!  or am I wrong?
The engine mods have been completed except for more coats of varnish. All metal removed has been replaced with wood and the cylinders lagged.Geoff

I will have to dig my K. N. Harris out and brew a pot of coffee before I answer.
Regards,
Gerald.

Gerald, I got my copy of Mr Harris's book out and found my calculations stuffed inside. Strength of copper when heated 11 tons=25000lbs safety factor of 8. = 
25000 divide by 8 = 3125lbs .   
Safe max pressure =
thickness of tube x 2 X 3125 divided by diameter of tube.
=.047x2x3125 div 1.02= 287.99lbs. 
  I think I did it right. Geoff