A Smaller Steam Engine For A Smaller Boat

apointofview · Jan 25, 2017

KBC · Jan 25, 2017

Hi Pete,
I seam to remember some where that you stated that you were just a beginner,
Some beginner !!!!
You are doing great work on that little machine and I for one have picked up some very good points and your pics are very informative..

Are you a trained machinist ?

Thanks for everything and the pics, I look forward to the engines first run.

George.

Cymro77 · Jan 26, 2017

I have been seriously questioning your statement "only a beginner" this work is way and above any "Beginner". Who you trying to confuse"

a41capt · Jan 26, 2017

Great work Pete! After seeing your videos of your stern wheeler, my interest has been piqued and to that end, I've been doing some research on the stern wheelers that served the lower Colorado River (from Mexico to the Grand Canyon) at the turn of the 19th century.

As an Arizona guy, and hobbyist historian, I've always been fascinated with these ultra shallow draft boats that built the territory and supplied the miners and Army. I even found the resting place of one of their boilers, although I'm not sure which one, along the ever changing riverbed.

Anyway, here are two pictures of the four boats that plied their trade along this treacherous piece of river, and perhaps someday I'll attempt to build an RC model to commemorate them.

John W.
Camp Verde, AZ USA

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a41capt · Jan 26, 2017

Oops, it appears that the second picture didn't attach. I'll try again!

apointofview · Jan 26, 2017

George and Cymro77, I guess I'm more of a hack than beginner anymore, I guess I feel that way because my tolerances seem to come out a bit loose. If I had to produce a part for someone else and they expected ( as they should ) for it to be per the drawing I wouldn't be able to do it consistently. I see the precision that the machine shop at work that supports the turbine engine and landing gear overhauls and can't begin to imagine keeping up with those guys !! I usually have to adjust what I make to account for screwups in dimensions, sometimes its not much, and sometimes its a design change

This is only the third engine I have made, the first was this one http://www.homemodelenginemachinist.com/showthread.php?t=14137
then the sternwheeler engines http://www.homemodelenginemachinist.com/showthread.php?t=22191 and now this one. The sternwheeler was a big jump and it took a long time but I learned a bunch doing it. I honestly have no formal training but I do have lots and lots of hours in this forum and youtube learning from you guys that are generous enough to teach your skills to me in posts and videos. Tubal Cain https://www.youtube.com/user/mrpete222 has an amazing collection of videos that cover just about anything I have had to do. I have broken lots of tooling and even the mill has been down for repairs because of my lack of knowledge, the scrap parts are learning opportunities and going by the size of that pile I have learned a lot

Anyway I really appreciate the compliments :thumbup:

John W - I'm glad I could inspire someone ! Those sure were neat machines and it's amazing to me what was designed and built back then with next to nothing for resources and tools. Those guys knew what hard work really means. That must have been fun to find wreckage of one of those machines, I have seen shots of a couple up in Alaska that have been discovered I envy you getting up close to that history.

Pete

KBC · Jan 27, 2017

Pete,

I have seen the video of your Stern Wheeler in action and thought at the time how realistic it was, I didn't know that you had posted a thread on the build of the engines for it and after having a quick look at some of the posts I am truly amazed at your workmanship considering that you are not a time served machinist.
I will give your thread some more views when I have the time to go thro' it all as what I have seen on the first few pages there are so many things that could help me in my machining efforts.
Thanks for taking the time to add the write up and the pics, I know it is a time consuming thing especially as the pics are so well presented.

Great work and it sure will inspire me to do better..
George.

apointofview · Jan 28, 2017

Thanks George ! I figure I gained lots of knowledge from guys willing to show how they did what they did, so why not try to help others with what little I know.
Pete

apointofview · Jan 29, 2017

Four more fitting are behind me. I took a lot longer to get these made because I tried to make them from oddball scraps to try to be frugal with my brass. I dropped back and punted on the first attempt it was gettin ugly fast. The second attempt was with a small stub of roundstock and it was working out ok till I came to the point of milling down the mounting flange. I had not thought this one thru far enough and had left the part with no good way to hold it for the milling. I ended up clamping the thin 5mm boss for the tube in the vise. That made marks and forced me to make a lot of very lite cuts and after all that I removed too much anyway! So all that time was toast and I got out a good size hunk of stock and cut all four from it. I turned down the flange dimension first drilled the nbr 30 hole and cut the first tube boss. Then I removed the chuck from the lathe and clamped it up in my vise. I have no idea if this is done in the real world but it worked and allowed me to keep the brass true when it went back to the lathe. I cut down the mounting flange on the mill, which took a lot of passes, and then pulled the chuck and mounted it back on the lathe. Then one by one I cut the tube boss and parted off the part. The holes for the 2-56 cap screws were next. I just lined up the part in the vise by sticking it on a nbr 30 drill bit mounted in the chuck and clamping it in the vise where the bit held it. Two little holes in each one and this job was done. Lots of time for what looks like hardly anything.
Pete

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Scrapped the part at this point

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Scrapped the part at this point

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apointofview · Jan 30, 2017

When it gets close to running it's hard to be patient! I still had to bend up the plumbing and solder it together. I don't have a tubing bender that can bend the little 1/8 tube. I didn't want to buy one and really didn't want to make one either. The plans describe putting the pipe in a groove cut into a scrap piece of metal and then bend it around a piece of round stock. That technique worked well enough for me. If I had to do more than these four pipes I would get a real bender. I had to modify the groove for two of the pipes because they change direction so quickly that the first bend wouldn't fit in the holding groove. Three pipes were scrapped because they didn't look good enough. They would have worked but I was being picky. I had to solder it up on the engine because the fit is so critical. I'm not using silver solder on the engine, just hard solder. It has held up fine on my other boat so it should do fine here. I rigged up a way to get air into it from my compressor. It took a little fiddling with the cam timing to get it to tick over but it wasn't long before I had a running engine !!!!! It still has a good amount of finish work I have to clean up the solder joints and a few tight spots. Right now there are no seals anywhere and the pistons don't have their carbon rings so the engine will run differently once all those are taken care of. That was a good day !
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And here is the video
https://youtu.be/zNoNKzi1REo

Pete

Herbiev · Jan 30, 2017

That's a great little runner. Well done and thanks for sharing.

bmac2 · Jan 30, 2017

Great work Pete
The engine looks to runs great at low pressure (<15lbs) and for myself at least that would be comforting in an RC boat. I know this is a work engine and it looks great in the pictures but . . . . . . in the video you got it dirty

Cant wait to see it in a boat:thumbup:

charlesfitton · Jan 31, 2017

Very nice work, and I'm sure you'll do a hull to match.

Nice to see that engine running so slowly. Seems that so many run the guts out of miniature engines, and all you can see is a blurr.

scottyk · Jan 31, 2017

Looks great and run smooth! nice work man. Its actually bigger than I thought when I see it completed sitting in the vise. Love it! Hopefully that boiler can keep up with it, cant wait to see work going on that again

a41capt · Jan 31, 2017

That's fantastic Pete! Such a small engine, and beautifully executed too. I'm looking forward to the boat you put it in!

John

apointofview · Jan 31, 2017

Thanks everyone ! I am really happy with it !!

It got really dirty really fast, I can't keep my other boat engine clean either, every run makes a mess just like the full scale engines I have seen ( the EPA wouldn't have liked the good ol days

). I have tried to make my engines run slow mostly because I like to see the movement, the side benefit is they don't use as much steam. I have no idea how fast the engine will need to turn to push along a boat. I have never dealt with a propeller.

I still have plenty to do but i am thinking i might hold off on the crank driven feedwater pump and and other misc items till I have a hull built. With a boat built I can design around the space I will have for the little stuff like plumbing and the controls etc. The boiler and engine are far enough along to get a good weight estimate for hull displacement. I might rig up a temp steam line from my operational boiler and give it a spin, but it would have to be a short run since I don't have a way to lube the engine yet.
Might be awhile before the next update, I'm not going to log the boat build, but updates on the running gear will show up when they happen.

Thanks for following along
Pete

Cymro77 · Feb 1, 2017

That is a very smooth , cool engine. Beautiful work. Can't wait to see it in a boat. Would also love to see a boat build - a particular interest of mine.

charlesfitton · Feb 2, 2017

[ I have no idea how fast the engine will need to turn to push along a boat. I have never dealt with a propeller....QUOTE]

Make the diameter as big as your engine will turn and not pop through the water surface, and with a little less pitch than a paddle wheel...

apointofview · Feb 3, 2017

Ok thanks, then I guess the hull has to be next to know what prop will fit underwater. I think this engine has plenty of giddy-up to turn a model size prop.

Blogwitch · Feb 4, 2017

Having a few years under my belt running steam screw driven model boats I can make a suggestion for your prop.

A bit of info first.

With a steam plant, the engine, when in the water and loaded with a heavy pitch prop will be running rather slowly, a lot slower than bench runs, in fact, they are just nodding along where you can easily see all the movement on the engine. This is because a steam engine produces a lot of bottom end torque and the faster they go, the more inefficient and steam hungry they become, so you can load the engine fairly heavily, my commercial 10mm bore x 20mm stroke at 40psi would easily turn a 75mm propeller, but I would always suggest something from 55mm to 65mm, and I would suggest something that size for your engine. It should easily power a model of 48" length or more, depending on hull shape.

Now comes the bit you might find difficult to obtain. Whatever size propeller you go for, it should have a heavy pitch. Here in the UK we can buy up to 45 degree pitch steam props and I don't know if they sell them where you live. I used to use the Raboesch range of props because they were soldered up from individual pieces (be careful as they also make and sell cast props which are difficult to modify) and had a heavy pitch on the blades, and if you need a bit more or less pitch, they can easily be 'tweaked'. Go to the bottom of this page.

http://www.westbourne-model.co.uk/a..._for_M4_Shaft_For_Model_Boat___Ship_Kits.html

I hope this helps a little

John

A Smaller Steam Engine For A Smaller Boat

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