7.25 inch Stevenson's Rocket

[terrier060]

Hi All
I have got a bit sidetracked as some of the members of our club are thinking of building a Rocket, probably a simplified version, but as a joint project.

Is there a publicised boiler design out there?  I am in the process of designing one, as you will see shortly, but as a new design, it would have to be approved for insurance purposes. So if anyone knows a person qualified to do this I should be very obliged to be put in touch with them.

One of the members has produced the firebox and rear end of the boiler using a 3D printer to my Fusion 360 design to make the join between the two parts easier to understand as those of you who know the Rocket, it has a firebox which is attached about half way up the barrel.  I will post some images in the next post.
Ed

[mbrown]

Do you have the book, "The Engineering and History of Rocket" by Bailey and Glithero? It has a huge amount if relevant detail including drawings and photos

Malcolm

[terrier060]

Hi Malcolm
No I do not have that book, but I have the Haynes Manual and also a complete set of drawings which I purchased many years ago from the NRM. These are fully detailed and drawn to 7.25inches scale, which is handy. I believe they used these to make the full size replica.

Here are the drawings I have prepared using Fusion360. Tony Sanders from our club has 3D printed them. It is an excellent way to see how the parts fit together, particularly the boiler. I will photograph them and show them in my next post.
I also have drawn a fully dimensioned 2D set in AutoCad.

Rocket 3D by ed cloutman, on Flickr

[terrier060]

Here are the 3D prints that Tony made for me. They are excellent and fit together really well so that you can see the complicated flanges very well on the throatplate and rear boiler barrel plate. I have modified the boiler to modern standards, as the original Rocket boiler had part of the firebox with a water jacket around it, but the rear tube plate was on the rear plate of the barrel. The front and rear of the firebox were partly of firebrick, so there was no foundation ring as there is on our boilers.  I have not shown any stays or bushes which the final drawings will indicate.  All the plates are 1/8inch copper and the barrel 3/32 inch seamless copper.  All will be silver-soldered and the working pressure will be 60psi.

If anyone knows a qualified person who could pass the boiler as a new design I would be very grateful to hear from them.

Firebox by ed cloutman, on Flickr

[Nigel Bennett]

One question, Ed - what are you going to do about a water gauge? The reason I ask is because I was contemplating a similar boiler for my 5"G Invicta, and this was one of a number of difficulties that eventually put me off the idea of a "Rocket" type boiler and I made a marine boiler instead.

[terrier060]

Hi Nigel
I have not shown the bushes as they are on the RHS, but they are basically as on the replica, but I have made the gauge glass longer, so as to cope with the higher and lower water level that might be expected on the model. You can actually just see them on the far side of the boiler. They are fitted to the rear end of the boiler barrel.
Ed

[terrier060]

Maybe I will see if Tony can 3D print the boiler complete.