The Steamboating Forum

Freezerrr12 wrote: ↑

Thu Aug 27, 2020 7:49 pm

I would like to address the readers of the forum with a few questions. I really hope to receive answers that will help me in further construction. What can be the maximum mass of moving parts of a steam engine to obtain high revolutions? The parameters are as follows. The weight of one connecting rod with bronze bearings is 5 kg, the weight of a piston with a diameter of 100 mm. together with the piston rod, crosshead - 5 kg. The weight of the piston with a diameter of 170 mm. - 4.5 kg. I designed a 132.5mm piston stroke. Do you think these parameters are outside the optimal range? Do they come out strong? The second question: what should be the area of ​​the steam bypass channels in such cylinders? I will be very grateful for the answers of knowledgeable people. I thank you for your help, I am attaching pictures of pistons and connecting rods for a general idea of ​​my project. My name is Ingvar.

Terrific workmanship, well done!

Regarding maximum RPM, all I can say from this distance is, “it depends”. There are plenty of formulas out there for calculating the minimum cross sections of connecting rods and piston rods, the minimum thickness of pistons, etc., but while your engine’s parts look a little heavy, they are not outrageously so. Form follows function, and as the saying goes, if it looks right, it probably is. I would think that your engine will be good for 500 RPM with no issues.

The weight of the reciprocating parts compared to the weight of the complete engine plays a part in how much of the vibration the mass of the engine is able to absorb. While a weight of 5 pounds of reciprocating parts in an engine that weighed 10 pounds would be disastrous, those same 5 pound weights in an engine weighing 100 pounds would be unnoticeable while running at the same speed. In avoiding using aluminum in your engine, it weighs more overall, making it more stable.

I am not sure about your meaning with the term “area of the steam bypass channels”. If you mean the steam ports, the steam should pass through them at 6,000 to 10,000 feet per minute. Take the average piston speed of the piston, at your maximum RPM, which is 5.2 inches stroke times 1,000 strokes per minute, which equals 435 feet per minute piston speed. 435 FPM divided by 6,000 FPM equals .073. So the area through the port should equal the area of the piston (12.17 square inches for the HP) multiplied by .073 , which gives us an area through the port of .89 square inches. If the length of the port is .8 times the bore of the cylinder (3.15 =.8 x 3.94 inches bore) , its height should be (.28 = .89/3.15 port length).

Keep up the good work.

Dear Fellow steamboaters. I apologize for my imperfect English. I have been working on my car for over 7 years. I'll post photos of what the steam engine looks like now, a little later. I have not yet found a boat hull for this engine and boiler. I think that the parameters of the boat should be like this. The boat is 28-29 feet long, 7 feet wide, draft -2 feet. Weight is about three tons. For the Volga River, which flows into the Caspian, this will be enough. At a distance of 150-350 km. from the city in which I live there are lakes of a decent size, but shallow with muddy water. As a place for water travel, they are not very suitable, but boats are suitable for testing. Delivery of a steam boat to the lakes is difficult, but
possible. I would like to welcome your thoughts on my steam engine. The sizes, that is, the area of ​​the park channels of a cylinder with a diameter of 100 mm, c one and a helf is larger than the recommended one Size - 70 x 13 mm. The area of ​​the steam passage (cylinder ports) of a cylinder with a diameter of 170 mm is also larger than the recommended by dear Kelly Anderson. I am worried about the effect of oversizing, area of ​​the steam passageways on the operation of the steam engine. An increase in the harmful space will lead to a decrease in power and a drop in revs. I also dream the boiler provides 100 sg. ft. heating surface. I have not chosen the boiler design yet, but I think it will be a water tube boiler. Such a boiler will have less weight. maybe one of you will tell me the design of the boiler, I will be grateful.

A few pies as promisead. My steam engine.

For me, pictures of my steam engine are better than pies. I am trying to attach pictures of my steam engine. Bed processing on a boring machine. Steam engine cylinders and spool box. I and my assistants made all the parts made of steel. Where I live, cast iron parts are not cast, it is easier to make steel. Machine machining is less expensive than making cast iron castings. Perhaps these photos will be interesting to someone.

Hi there, the steam engine enthusiasts! I have previously incorrectly stated the weight of the bronze bearing rods. In fact, each weighs more than 9 kg (over 20 pounds). This worries me, and I will take measures to lighten them. I will try to attach photos. I previously wrote that I dream of having a boiler with an area of ​​100 sg / ft., but I think that the construction of such a water tube boiler will take a long time, it will be very difficult. Please, give me advice, - which boiler should I start building? I hope that next spring and summer I will be able to finish my steam engine. I recently managed to acquire a garage that I have rented for the last 10 years. I brought some machines there, practically bought at a junkyard. In the past years I had to restore these machines to an acceptable condition. I managed to make many details that do not require great precision on these machines. With the rest, more precise details (connecting rods, crankshaft, plate), my assistants helped me. After finishing the construction of the steam engine, I will have to build a boiler. I really look forward to receiving practical advice from you dear steam engine enthusiasts on how to build a boiler suitable for a steam engine! Thank you in advance!


Пятница, 4 сентября 2020, 22:56 +03:00 от Ирина ввв <antonova_i00@mail.ru>:

I salute the steam engine enthusiasts. I have previously incorrectly stated the weight of the bronze bearing rods. In fact, each weighs more than 9 kg. - over 20 pounds. This worries me, I will take measures to ease them. I will try to attach photos. I previously wrote that I dream of having a boiler with an area of ​​100 sg / ft., But I think that the construction of such a water tube boiler will take a long time, it will be very difficult. I would like you advance, - which boiler should I start building? I hope that next spring and summer I will be able to finish my steam engine. I recently managed to acquire a garage that I have rented for the last 10 years. I brought some machines there, practically bought at a junkyard. In the past years I had to restore these machines to an acceptable condition. I managed to make many details that do not require great precision on these machines. The rest, more precise details (connecting rods, crankshaft, plate), were helped by my assistants. After finishing the construction of the steam engine, I will have to build a boiler. I really look forward to receiving practical advice on how to build a boiler suitable for a steam engine.


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Анастасия Антонова

What is important is that your boiler should be a reasonable match with your engine, and your hull should have enough buoyancy and structure to support all of the weight of the steam machinery.

Steam equipment is quite heavy. If you look at how many kg of all the equipment per horsepower, it is high. There is no easy way to completely eliminate this hard fact.

I bought an old 24ft pontoon boat, and then added a third 20ft pontoon just to support most of the weight of my boiler which weighs approximately 1000lbs dry for ~6HP.

You can do it!

-CB

P.S. In my case my 6HP steam engine is only 200lbs by itself. Maybe there are some areas of the engine you can reduce in weight....

Dear KB thank for the feedback. I understand that the weight of the steam boiler will be at least 1000 pounds. The weight of my steam engine will be about 750-800 pounds, for which I will have to look for a large boat, which is what I'm doing now. I would like to make something like a scoteh boiler, but I'm afraid it will be very heavy. If I can make a scoteh boiler with a 100sg / ft heating surface, will it weigh no more than 1000 pounds without water? Maybe some of the enthusiasts know the parameters of such boilers? I also ask for advice on the diameter of the drains at the both ends of the cylinder. One cylinder- 100 mm., Second cylinder -170 mm. I would be grateful for the information.

Dear KB thank for the feedback. I understand that the weight of the steam boiler will be at least 1000 pounds. The weight of my steam engine will be about 750-800 pounds, for which I will have to look for a large boat, which is what I'm doing now. I would like to make something like a scoteh boiler, but I'm afraid it will be very heavy. If I can make a scoteh boiler with a 100sg / ft heating surface, will it weigh no more than 1000 pounds without water? Maybe some of the enthusiasts know the parameters of such boilers? I also ask for advice on the diameter of the drains at the both ends of the cylinder. One cylinder- 100 mm., Second cylinder -170 mm. I would be grateful for the information.