Ambitious project - model of Irrawaddy paddler "China" in 1 : 48 startet

[derekwarner_decoy]

Yes Thomas......if any model steam boiler seam or joint fails at ~~ 3 Bar, there is no explosion......just as you say a jet of steamy water..........

With respect to the 2 Bolt oval SAE style flanges [with 2mm bolts] the surface area for the gasket sealing is very small......Winfried Niggle produces these same sizes 2 bolt oval flanges with o-ring sealing

Here is the example of Winfried's flanges

So impressed with using industrial principals for the model world, he manufactured 4 an 5 bolt round flanges for 1/8" and 5/32" tube for my build

Derek

[Mechanicboy]

Hankwilliams: I also never heard about any exploding model boilers. May be, that the doubtfulness of exploding boilers is more a psychological problem.

The boiler must be strong enough before the vapor pressure moves past safety valve. I'm not sure how big the safety factor is set to boiler made of brass made by Saito Seisakusho co.


How to calculate required thickness of shell in inchess or working pressure :

For a boiler made of copper, the safety factor is set to 8. ---> 25 000 Lb/sq.in / 8 = 3125 Lb/sq.in

Thickness of boiler shell in inches: Thickness in inches = Working pressure PSI x Internal diameter of shell in inches : 2 x 3125 Lb/sq.in

Working pressure:  Working pressure PSI = 2 x 3125 Lb/sq.in x Thickness in inches : Internal diameter of shell in inches

About exploding boiler.. I looked at the film of exploding boiler, the reason was that the novice had not put on the safety valve or safety valve failed on self-made boiler, so he could not know how much he had steam pressure into the boiler before the boiler exploded.  See this movie --->

https://www.youtube.com/watch?v=-GqXQvXZnsw


I has 2 Saito boiler, it is a B2F  from 1988 and the older boiler from 1975-80 B2E. Still in good condition. Important: Remove water from boiler after use.

[Hankwilliams]

Very interesting. The boiler in the video must be heated before, the time of heating seems much too short.
Concerning the material of brass: Some model makers are saying, that brass will be weaken after longer time because the zinc portion as the non precious metal will be washed out. In the reality I  never heard about this.
But I think the advice of removing water of the boiler after use is important, I also have done this.

Thomas

[derekwarner_decoy]

Thomas......this is getting a little away from your thread, however should be explained

The de-zincification of brass does occur when brass material is eroded by galvanic process when by example we have a brass boiler shell with red brass/bronze bushings joined by silver soldering

The less noble metal [Zn] is leached from the brass by the galvanic action. The leaching takes place in the closest proximity to the silver soldered joint

This is evident [to the human eye] by pitting to the brass surface substrate surrounding the actual joint

Naturally the pH value of the water used in the boiler will have a direct contribution to the rate of process of de-zincification occurring

In Australia, we follow the British model steam boiler codes which essentially dictates that these  are constructed from copper [being 99.9% pure oxygen free material]

Derek 

[Hankwilliams]

Yes Derek, thank you for your conclusion. The theoretical backgrounds about the attributes of alloyings like brass and semi-precious metals like copper are very interesting. And of course I accept this scientific backgrounds. In practice, a copper boiler will much more durable than one made of brass.
I wrote in a past post, that also here in Germany this question - brass or copper boiler - seems almost a question of faith.

For me more practical reasons of the building speaks for a brass boiler: It´s much more easy to silver solder bigger brass parts than copper. Brass is more hard and its better for sawing.
In history and archäology brass is similar to bronce a very long known alloying, there were millenary old brass made vessels found - in good condition.

Thomas

[Hankwilliams]

Hi friends and neighbors,

although I write a few weeks ago, that all with engine and boilers seems ok, I improved some parts: The bearings of the paddleshaft have had too much powerslidge (?), the condensor was too small and the reversing by R/C wasn`t reliable. It also took some time, to install the radio control in the precise manner. In the meantime I did more than 10 test runs with R/C, now it seems allright.
In the pictures you will see the whole engine/boiler area with radio control. In the two last pictures you see the connection of the rudder - it`s not quite original, but the original connection with chains would be too less stable in the model.
I will continue now with the superstructure of the upper deck. Hope you will enjoy the pictures!

Thomas

[derekwarner_decoy]

Hullo Thomas.....progress is good...and as always....

You note your original condenser [de oiler] was too small......what volume was it? and what is the volume of the new de oiler?

For interest, what foot print mm x mm of your engine drip tray?

"too much powerslidge " ....not sure what this means

I see you are using a Niggle 400112 lubricator with the variable oil metering.....I chose  [for what ever reason] the 419111 fixed orifice lubricator but with the discharge blow down needle valve in the base of the lubricator and this is tube connected to the de oiler.....

This also allowed me to minimise the size of the engine oil drip tray [still 150mm x 140mm] by placing the lubricator in a more convenient location

I too intend to have chains on my paddler rudder, but found fused link miniature chain near impossible to purchase in scale [without using gold jewellery chain] and the proximity of the rudder post precluded  any reasonable length fulcrum arm

The solution I will copy from a Swiss builder is to use miniature ladder link chain from the servo chain pinion to a similar sized chain pinion on the rudder post.......this gets me down to say 16 mm diameter pinion on the rudder post.. the build here is for a twin rudder, but the principal will be the same for single.......this hopefully all me to use moving [non-load bearing] scale chain

Derek

[Hankwilliams]

Hi Derek,

may be, there is a little misunderstanding - with condenser I mean the hotwell for the exhaust steam and water, not the oiler. The new one I made from an usual in trade copper tube of 28 mm diameter and a lenght of 380 mm, contentment is approximately 200 cc.
The old one with only 85 cc was too small, after 15 - 20 minutes it was full of water.
With the Niggle lubricator the oil consumption of the engine is very low, after a test run I only had to remove some drops of water in it, oil was still enought.
The correct expression of what I mean with "powerslidge" ist bearing play, free play or bearing slackness of the paddleshaft - sorry, some technical expressions were not in my dictionary. The free play was about 0,1 mm - too much for exact straightening of the wheels.
Your connection with chains between the servo and the paddle rudder seems good, also the angle of the rudder is rather wide.

When I continue with the upper deck saloons, there is a difference between the plan of "China" an the only photo. In the photo the saloons for and aft are much more longer than in the plan, also between the funnels seems to be a further small saloon or deckhouse, which isn`t on the plan.

I think, it will be better and more realistic to make this parts after the photo.

Thomas

[derekwarner_decoy]

Hullo Thomas......by now you may have had a chance to see how the Regner boiler feed pump is working... I am assuming your pump is running at paddle shaft speed of ~~ 60 to 160 RPM?

a. Any issue with deflection of the extended push shaft?
b. Some say the shaft driven pump takes too much power....do you find this?
c. I cannot translate the Regner catalogue in .pdf to English
d. It appears as a complete pump assembly with bypass valving and accumulator comprise as follows
__________
 
one x 40810 @  Euro  86.00
one x 30120 @  Euro  16.50
one x 40821 @  Euro  28.00
one x 40822 @  Euro  55.00                   
                    Euro 185.50

Am I correct here in my assumption of the components required to make one complete pump assembly as you have shown?
Does this include the screwed port solder/compression tube fittings?

This is Euro 185.50 or AUD$272.00 which is not that expensive really compared to Euro 640.00 for their steam driven water pump

If you give this pump a good report, I will seriously consider the purchase of the same..............
If there were any other publication that could be translated would be very helpful

e. is the eccentric shaft hole 4.0mm?
f. what is the footprint size of the pump block?.....~~30x45?
g. what is the height of the envelope size
h. is the block tapped M? underneath for mounting?

As I have mentioned, the people from Regner do not really appear interested in talking with me in supplying one x unit to Australia

This is very disappointing, as I find people like Winfried Niggle absolutely good to communicate with and hence have purchased many items from him.....

Derek


 

[Hankwilliams]

Hi Derek,

many questions - I hope, I will answer in a sufficient way.

Yes, the feed pump is composed at the four items you wrote, price is about 186.- Euro. Many years ago I used only the hand feed pump 40820 with 30120 but without 40821 and 40822 for a stationery 12/36 engine, it was working well after some untightness at the beginning. Its a kit and the whole parts are unchanged since more than 25 years`. The compressing tube fittings with M 2 screws are included. The eccentric shaft is 6 mm like the shaft of the bigger Regner engines (shaft between clutches and paddlewheels only 4 mm). The footprint size of the block is 35 to 20 mm, the complete height over air chamber 40821 is nearly 100 mm - in my model it`s a little higher because of the position of the bypass valve. The block is fixed with M 2 screws underneath.

At the test runs the feed pump was working well, but only when in the compression tube to the boiler valve is no air. It may be neccesary to sever the fitting to the boiler valve until water comes from the pump like in the picture. With the bypass valve one can regulate the quantity of water. This last point seems very important, until now I don`t have sufficient experience about the practice when the boat is running on water. As far I see, the pump doesn`t need much power of the engine it`s a long stroke engine and the RPM are not very fast-  as you wrote.
I`ll send a few pictures in the next post.

Thomas

[Hankwilliams]

Hi Derek and all friends and neighbors,

Here some pictures of the feed pump and the whole impression of the boat with the funnels. Next work will be the upper deck saloons - in the moment I don`t feel like with this woodwork at the nice summer days...

Thomas

[derekwarner_decoy]

Thanks Thomas for the detailed answers......yes, piston pumps of this type must have all air bled....

I may need to install a vertical water riser bleed tub e& valve....similar to the image

Derek

[derekwarner_decoy]

More question Thomas...

I believe you may have the Elde Modelbau wheel set Number A1100...this is listed as 1:25 scale, however looks fine in sizing with your 1:48 scale build....I am considering the same wheel set in my 1:20 scale build

The WEB site does not confirm, however could you please confirm the shaft size....is it 4mm diameter?

Interestingly, they display the Saito Y2DR horizontal engine in their WEB site along with the wheel sets......[the same engine that I have]

Derek

[derekwarner_decoy]

Thomas.....Manfred from Elde Modelbau tonight has kindly sent over Drawings for the A1100 wheel set

So as not to pinch your build thread I will send a PM with the communication with Manfred and a few more questions

Derek

[Hankwilliams]

Hi Derek,

yes, I have the wheel set A1100. It`s an very exact model in 1 : 25 of the wheels of the Elbe paddler "Kaiser Wilhelm". The original position of the excenter is between ships side and paddle, but it was no problem to alter this to outside excenter.
The paddle shaft is 4 mm. Diameter of the whole wheel is about 125 mm, it depends of the positions of the paddles. First I fixed the wheels with rings and adjusting screws to the shaft, but this was too less solid - later I glued with loctide wheel and shaft. This is now one unit until the clutches to the engine shaft.
The wheels seems solid, material is 1 mm brass, braced with bolts.
I add pictures of the Elde wheels compared with the very light build wheels of my "Marchioness of Lorne" (Glasgow models), the home made wheels of my"Hope" and my "Tachtalia".
Althought the costs of the Elde wheels are very high, one gets a good equivalent as I think. As I wrote, the kit is pretentious, it takes some time to assemble it with the tiny M 1 screws and nuts.
I hope, I could answer your questions.

Thomas