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I would like to build a small model aircraft engine, you know, like the little one on the right in this photo, with a 2" bore. Got big or go home. (Not my photo).

Steady rest, see post #23, starting at the 3rd photo down from the top. .

Bill Hall created some awesome steam engine white papers. I have some of those. .

I could do a sleeved aero engine, aluminum cast block with gray iron sleeve, but the bore would have to be 2" minimum. So a big aero engine. The trend these days in the model airplane world is BIG scale planes, as in like 12 foot wingspan planes. I had a buddy who build a 1/2 scale piper cub...

Brass bearings ? Yikes ! Well, I actually bought the Stuart kit because I like the Stuart brand a lot (it is an iconic brand), and it is fully machined, so I don't have to try and machine a smaller engine. But mainly I bought it because it was 1/3 the price of the same kit from Stuart. I will...

I have transitioned away from aluminum in the shop for anything except permanent pattern castings, using alloy 356. I got tired of the tool bit and drill bit loading up with aluminum that was not heat treated, and the ease at which aluminum threads strip out. So no aluminum in my shop except...

I seem to recall that the first docking stations in space where precision machined and polished surfaces, and when they docked, they stuck together like superglue. I think that is when they started coating the mating surfaces with teflon. I will have to look this up, but I am sure it is true...

LOL, I call it "The War Department". .

There is a story in Charles Porter's book about how he delivered one of his steam engines to a steel mill, and it was about 1/3 the engine it was replacing. The manager saw the engine when it was delivered, and ordered that it be sent back to Porter, saying something like "That tiny engine will...

I found my PLAN spreadsheet, and it is as follows: P = mean effective pressure (psi) L = length of stroke A = area of piston N = revolutions per minute (rpm) When I punch in the numbers for the 10hp 7" bore engine from the previous chart, I have to crank down the mean effective pressure to 40...

Someone with a screen name of Gary K posted this online. It seems to make sense. Steam Engine Horsepower Example: An engine with a 9” bore, a 10” stroke, a speed of 250 rpm, and 150 lbs. boiler pressure – The size of a 50 H.P. CASE steam engine. P = 50% of 150 = 75 lbs. L = 10 / 12 or .833...

Here is a continued discussion of how to calculate steam engine horsepower. .

We need to split this topic off. I will start a new thread. https://www.homemodelenginemachinist.com/threads/calculating-the-horsepower-of-a-steam-engine.35693/#post-404167 .

The "mean effective pressure" is not the same as the pressure in the line to the engine. I forget all the in's and out's about it. That is the equation I had in my spreadsheet. I can't recall why the division by 12. I had this all written out, and now can't find it. I am assuming that if the...

That is a nice steady rest. I had not noticed that. .

If it is just the cylinder lagging, I will do that in brass sheet, and make a pattern from cardstock, but thanks very much for the offer of help. I appreciate it. .

At 800 rpm, the equation above yields 1.28 hp (indicated). Seems like they are using the rpm to inflate the hp a bit. .

Lets do a quick calc for the 5A. P = 40 psi (an assumed number that may or may not be accurate) L = 2/12 = 0.166666 A = pi * 2.25/2 squared N = 300 rpm (assumed value) Horsepower (indicated) = (2*P*L*A*N) / 33,000 { 2 * 40 * 0.166666 * 3.97 * 300 } / 33,000 = 0.48 hp (indicated) .

I think you are correct. Thanks much for that. I don't really need this kit, but purchased it because of the price, so if anybody really wants this kit, I will consider passing it on at cost plus shipping. It may be such a nice kit that I decide to keep it though. We will see if it arrives...

I found my PLAN spreadsheet, and it is as follows: P = mean effective pressure (psi) L = length of stroke A = area of piston N = revolutions per minute (rpm) When I punch in the numbers for the 10hp 7" bore engine from the previous chart, I have to crank down the mean effective pressure to 40...