Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines
Office of Steam ~GLOBAL POWER-UP~ virtual engine show => ENGINEERS HALL at Our 2024 GLOBAL POWER-UP -- Virtual Engine Show…!!! => Topic started by: Nick on March 03, 2024, 10:08:26 pm
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While not perfect the ai helps
* **Incomplete exhaust:**
I think the ai text is stating that the port at bdc must take away from the total stroke. If it's open at the last 1% then that engine is only 99% as efficient as one that doesn't have a port.
Also that port stops the scavenging effect of the valved exhaust. Although perhaps that could be mitigated by routing both to a common exhaust pipe.
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* **Fresh air loss:**
Indeed it was clumsy on its wording for the intake stroke. Basically on the bdc of the intake/compression stroke some of the intake charge will be lost to the open exhaust port.
Good points.
However regarding exhaust port taking away a bit of the power stroke, there likely would not be a noticeable efficiency or power loss given that the the bottom 5-10% of the power stroke provides a miniscule amount of power/torque given the limited amount of piston travel. This open port design clearly did not grow much over time with the exception being 2 cycle engines. As for scavenging, the intake valve on a Gade is atmospheric and doesn't let in any fuel/air until the piston is traveling downward and creates a vacuum. On non-hit & miss engines (without any open ports) the intake cam lobe could be timed to begin opening before top dead center on the exhaust stroke which allows for some scavenging.
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While not perfect the ai helps
* **Incomplete exhaust:**
I think the ai text is stating that the port at bdc must take away from the total stroke. If it's open at the last 1% then that engine is only 99% as efficient as one that doesn't have a port.
Also that port stops the scavenging effect of the valved exhaust. Although perhaps that could be mitigated by routing both to a common exhaust pipe.
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* **Fresh air loss:**
Indeed it was clumsy on its wording for the intake stroke. Basically on the bdc of the intake/compression stroke some of the intake charge will be lost to the open exhaust port.
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This AI looks smart but a little ignorant too.
The BDC port is aways open and has no valve or flap.
It only let's out exhaust when the piston moves past it to BDC exposing the port. As soon as the piston moves moves up near an inch from BDC, it is "closed".
This AI is also confusing the intake stroke with the compression stroke. intake stroke is always downward.
Most interesting is that AI writes in good English that is easy to understand.
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Gemini is a very smart AI assistant!
I asked about tye disadvantages of ported exhaust at BDC:
Some early four-stroke engines did have an exhaust port at the bottom dead center (BDC) in addition to the usual top exhaust port. This design aimed for better cooling of the cylinder head, but it came with several disadvantages:
**Loss of efficiency:**
* **Incomplete exhaust:** With the BDC port open during the exhaust stroke, some of the unburnt fuel-air mixture and hot exhaust gases could escape prematurely. This reduces the pressure available for pushing the piston down on the power stroke, leading to lower power output and wasted fuel.
* **Fresh air loss:** As the piston starts its upward stroke for the intake phase, the BDC port might still be slightly open. This allows some of the fresh air-fuel mixture being drawn in to escape through the bottom, reducing the amount available for combustion and further impacting efficiency.
**Lubrication challenges:**
* **Oil loss:** The BDC port's location near the crankcase could lead to engine oil escaping with the exhaust gases. This increases oil consumption and requires more frequent top-ups.
**Complexity:**
* **Design and manufacturing:** Having two exhaust ports adds complexity to the engine design and manufacturing process. This can make the engine more expensive to produce and maintain.
**Overall, the efficiency and lubrication drawbacks of the BDC exhaust port outweighed the benefit of slightly better cooling. Modern four-stroke engines rely on improved engine design and materials for efficient cooling, eliminating the need for this less effective approach.**
Here are some additional points to consider:
* This design was more common in very early four-stroke engines, likely single-cylinder models.
* The BDC port might not have been a fully open port but rather a timed opening or slot that remained open for a shorter duration to minimize the efficiency losses.
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In the last photo of reply #20.... Nice to see the little brass/bronze vertical behind the red steam engine. It is the smallest Sipp engine and was introduced inside the back cover of the 1895 Sipp catalog.
Gil
Gil @RedRyder , here are some better pictures of the engine that the owner texted me last night. Can you confirm that it is a Sipp after seeing it up close? He has had the engine for 25+ years and didn’t know the maker.
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Thanks for the great pictures.
I love the cement mixer!
Any history on it?
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Nick, it looks like a fantastic display and play day..!!!
I enjoyed every second of the video.
Are those Kevin built Dray Line wagons in tow behind the brass & black Wilesco TE.?
In the last photo of reply #20.... Nice to see the little brass/bronze vertical behind the red steam engine. It is the smallest Sipp engine and was introduced inside the back cover of the 1895 Sipp catalog.
Gil
Yes, they are Kevin’s wagons :)
Very cool about the Sipp, wish I had known that!! I will have to text the owner who I just met. He told me he watches your videos all the time and would love to talk to you sometime.
Nick, you can send me his name & phone# if you like and let him know I will give him a call. You can give him my number as well.
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Thanks for the video Nick. I definitely need to upgrade my popcorn-making system!
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Nick, it looks like a fantastic display and play day..!!!
I enjoyed every second of the video.
Are those Kevin built Dray Line wagons in tow behind the brass & black Wilesco TE.?
In the last photo of reply #20.... Nice to see the little brass/bronze vertical behind the red steam engine. It is the smallest Sipp engine and was introduced inside the back cover of the 1895 Sipp catalog.
Gil
Yes, they are Kevin’s wagons :)
Very cool about the Sipp, wish I had known that!! I will have to text the owner who I just met. He told me he watches your videos all the time and would love to talk to you sometime.
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Nick, it looks like a fantastic display and play day..!!!
I enjoyed every second of the video.
Are those Kevin built Dray Line wagons in tow behind the brass & black Wilesco TE.?
In the last photo of reply #20.... Nice to see the little brass/bronze vertical behind the red steam engine. It is the smallest Sipp engine and was introduced inside the back cover of the 1895 Sipp catalog.
Gil
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This is from the show, a Canfield? Or Camfield? I didn't get the correct spelling I don't think. (Can someone tell me? 😀)
Anyhow, what is interesting about this engine is that it has 2 exhaust ports. One is at bottom dead center. The idea is to have the engine run cooler.
Hi Chris, Canfield is correct. It's the black engine with the vertical brass water tank.
The Canfield and the Gade both have an exhaust port at each end of the stroke. The Canfield ports are on the top of the cylinder and the air cooled Gade are on the side. I believe the thinking was simply if the remaining hot gas under pressure at the bottom of the stroke has a place to escape, it will aid in cooling as much less of it (hot gases) will need to be pushed back to the top dead center to be forced out the exhaust valve at the head. Hope this helps.
Gil
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After collision with RC truck :D
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Chris’ Table
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Inge’s Table
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My tables (also posted in Nick’s Table)
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This Tiny Power Case 65 was built by member Jerry’s father in 1957
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His Wilesco he was given at age 7
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And another built by his father
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Thanks Inge. It's a real beauty. I've seen one other like it which I think was also 3.5" gauge and may have also come from BL. Was talking with a friend the other day who used to go to the Steam Age shop in London. I restored a 3.5" gauge GNR Atlantic from about the same period. Just a tidbit of info--Patrick Stirling, designer of this loco, was the son of Robert Stirling who invented the hot air engine.
If the other one you seen was another forum members, this may be the same one ;)
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Thanks Inge. It's a real beauty. I've seen one other like it which I think was also 3.5" gauge and may have also come from BL. Was talking with a friend the other day who used to go to the Steam Age shop in London. I restored a 3.5" gauge GNR Atlantic from about the same period. Just a tidbit of info--Patrick Stirling, designer of this loco, was the son of Robert Stirling who invented the hot air engine.
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Thanks. Any idea what gauge it is and if he steams it?
The Stirling Single if 3/4" scale, 3-1/2" gauge. Runs great on air but has a small leak in the firebox which I have not addressed yet. Construction is attributed to Bassett Lowke, probably in the 1930's. Says Bassett Lowke on the pressure gauge, and reportedly came from the old Steam Age shop in London.
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Thanks. Any idea what gauge it is and if he steams it?
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Love your Stirling single locomotive Nick. Can you tell us more about it?
That belongs to @Inge
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This is from the show, a Canfield? Or Camfield? I didn't get the correct spelling I don't think. (Can someone tell me? 😀)
Anyhow, what is interesting about this engine is that it has 2 exhaust ports. One is at bottom dead center. The idea is to have the engine run cooler.
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It's amazing how much power it takes to cut wood. I ended up using a fine tooth Dremel saw blade on mine.
Nice collection!
I'll have to check out the Dremel saw blades... :) A big factor in how well the saw rigs work is the blade quality. Warped or wobbly blades really have a lot of drag.
I've also noticed that cutting with the grain or cross the grain makes a big difference.
A good idea is to have a flywheel on the saw itself but most toy saws don't have space for it. Pulley ratios matter a lot too. Sometimes it's best to spin it fast sometimes it's best to spin with more torque, depends on the engine. In regards to the engine, sometimes need to fire more vigorously.
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It's amazing how much power it takes to cut wood. I ended up using a fine tooth Dremel saw blade on mine.
Nice collection!
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Great stuff!
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Love your Stirling single locomotive Nick. Can you tell us more about it?
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Looks like a great show. I was surprised at the loads being pulled by the Wilesco engines. And love that classic old Case traction engine model.
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Love the wagons .... even when they are not full of beer!
Nick my good Sir, my hat is absolutely off to you for your masterful job of juggling all of this weekends madness, and doing it with grace and style! Every time I think you must be overwhelmed by all that is going on, you go and add another facet to all that you are already doing!!!
Thanks for this most recent video, and THANKS for putting this whole weekend on the map for the rest of us too!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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Thought this weekend’s show deserved it’s own table ;) I have shared CBWho, Inge, and my own tables, but I will add pics from the others after the video
https://youtu.be/gmvbOc5GVJ8