Zdenek in the Czech Republic

[Zdenek Hadrbolec]

There are many on the forum that have CNC so even solid models would be useful as long as they are in one of the formats like .step or another widely used format. Even those that don't have CNC could create their own drawings from .step files.

The coils are wound on a classic core made of silicon sheets. Always from nine wires with a diameter of 0.4 mm, five turns each. The motor is 36 poles with 42 magnets. Or maybe 72 poles/84 magnets, it doesn't matter... :-D

 

[petertha]

Thanks for your replies & additional pictures. Some very innovative work there!

On your glow engines, is lubrication entirely from oil content in nitromethane (mist lubrication) or do you have some sort of enclosed oil bath, particularly in the nose case / cam plates / planetary gear drive area?

Did you make your own connectors to the glow plug stem, or possibly purchased like these ones (my radial)?

 

[Zdenek Hadrbolec]

Thanks for your replies & additional pictures. Some very innovative work there!

On your glow engines, is lubrication entirely from oil content in nitromethane (mist lubrication) or do you have some sort of enclosed oil bath, particularly in the nose case / cam plates / planetary gear drive area?

Did you make your own connectors to the glow plug stem, or possibly purchased like these ones (my radial)?

I only lubricate with a mist, the front sometimes drips with oil. I have some endings like that, I don't like them very much. Are yours perfect, is that your work or can they be bought somewhere?

 

[petertha]

I got my glow plug / harness form AliExpress, this store.
https://peakmodel.aliexpress.com/store/5569111?spm=a2g0o.order_list.0.0.5fd61802wH3t9o
They make 2 sizes to fit glow plug stem diameters properly, what they call red & black as per description attached. The color just corresponds to their own size designation, the contact spring inside the brass fitting is what mates to the plug stem. I bought some of each to test, they fit both style of plugs as advertised very well & provide good electrical conductivity. Black fits my OS-F plugs perfect. Yesterday I snipped off the heat shrink & can see the wire is butt soldered axially to the brass cup. But it is possible to turn the wire more at 90-deg & apply replacement heat shrink so it sits that way & looks a bit more like a spark plug boot. I have not run these yet but I don't expect problems with vibration. They could also be shop made now that I see them, but for the price & fiddling around, just as easy to buy.

I'm working on my glow ignition box now so hopefully will get caught up on my (Ohrndorf 5-cyl) build post & report back how this worked out.

 

[petertha]

I forgot to mention, I also saw these right angle harness connectors with integral boot also on AliExpress. But they did not specify a glow plug stem diameter like the previous link I posted. I assume they are for the slimmer stems *typically 2-stroke glow plugs) because I se them used there, but I'm not 100% certain. I think they are too shallow to fit n my head anyways, so that's why I got the in-line axial ones mentioned & I think I can curve the wire path anyways.

https://www.aliexpress.com/item/100...416612269525658319efb12!12000018843233036!rec

 

[Olli-Matti]

Great stuff Zdenek! May I ask what kind of mill do you use for making these parts?

 

[Richard Hed]

The coils are wound on a classic core made of silicon sheets. Always from nine wires with a diameter of 0.4 mm, five turns each. The motor is 36 poles with 42 magnets. Or maybe 72 poles/84 magnets, it doesn't matter... :-D

THis is very interesting, however, I am not clear about it. You say nine wires--what does that mean? I really don't get that. I would have wrapped each coil with a single wire. How do you do nine wires?

 

[Wheat47]

I understand and I have no doubt about it. I just wrote that cnc files are unnecessarily complicated for manual production. If someone wants to build my engine, we can somehow agree on the *.stl files.

Hi to all! My name is Zdeněk, I'm from the Czech Republic and I make radial model engines. I started with small displacements, the most I built were five-cylinders with a capacity of 25 cm3, now I have two nine-cylinders with a capacity of 220 cm3 under construction, but that is too much for me. I will go back to smaller cubic volumes. My engines are always four-stroke, the smaller contents are for a glow plug, the larger ones with a spark plug. The plans are big for the future, so we'll see!

Where in the Czech Republic are you??

 

[Zdenek Hadrbolec]

I got my glow plug / harness form AliExpress, this store.
https://peakmodel.aliexpress.com/store/5569111?spm=a2g0o.order_list.0.0.5fd61802wH3t9o
They make 2 sizes to fit glow plug stem diameters properly, what they call red & black as per description attached. The color just corresponds to their own size designation, the contact spring inside the brass fitting is what mates to the plug stem. I bought some of each to test, they fit both style of plugs as advertised very well & provide good electrical conductivity. Black fits my OS-F plugs perfect. Yesterday I snipped off the heat shrink & can see the wire is butt soldered axially to the brass cup. But it is possible to turn the wire more at 90-deg & apply replacement heat shrink so it sits that way & looks a bit more like a spark plug boot. I have not run these yet but I don't expect problems with vibration. They could also be shop made now that I see them, but for the price & fiddling around, just as easy to buy.

I'm working on my glow ignition box now so hopefully will get caught up on my (Ohrndorf 5-cyl) build post & report back how this worked out.

I use this, but it's hard to find anymore. I don't know the correct name.

Where in the Czech Republic are you??

Pilsen.

 

[Zdenek Hadrbolec]

THis is very interesting, however, I am not clear about it. You say nine wires--what does that mean? I really don't get that. I would have wrapped each coil with a single wire. How do you do nine wires?

It's simple: one wire must have a diameter of 1.2 mm (cross section 1.13 mm2). Such a wire cannot be wrapped around a 4x4mm core. It is very thick and hard. Therefore, nine wires with a diameter of 0.4 mm are folded together. These easily adapt to sharp bends. At the ends, all the wires are connected together and then behave as one wire with the same cross-section of 1.13 mm2.

 

[Zdenek Hadrbolec]

Great stuff Zdenek! May I ask what kind of mill do you use for making these parts?

Thanks friend. I use a Roland MDX40A and a China router 9060, but properly modified.

 

[Zdenek Hadrbolec]

I got my glow plug / harness form AliExpress, this store.
https://peakmodel.aliexpress.com/store/5569111?spm=a2g0o.order_list.0.0.5fd61802wH3t9o
They make 2 sizes to fit glow plug stem diameters properly, what they call red & black as per description attached. The color just corresponds to their own size designation, the contact spring inside the brass fitting is what mates to the plug stem. I bought some of each to test, they fit both style of plugs as advertised very well & provide good electrical conductivity. Black fits my OS-F plugs perfect. Yesterday I snipped off the heat shrink & can see the wire is butt soldered axially to the brass cup. But it is possible to turn the wire more at 90-deg & apply replacement heat shrink so it sits that way & looks a bit more like a spark plug boot. I have not run these yet but I don't expect problems with vibration. They could also be shop made now that I see them, but for the price & fiddling around, just as easy to buy.

I'm working on my glow ignition box now so hopefully will get caught up on my (Ohrndorf 5-cyl) build post & report back how this worked out.

Thanks friend. I use this. But I can't find it anymore because I don't know what it's called exactly. If anyone knows where to buy I would appreciate it!

 

[Richard Hed]

It's simple: one wire must have a diameter of 1.2 mm (cross section 1.13 mm2). Such a wire cannot be wrapped around a 4x4mm core. It is very thick and hard. Therefore, nine wires with a diameter of 0.4 mm are folded together. These easily adapt to sharp bends. At the ends, all the wires are connected together and then behave as one wire with the same cross-section of 1.13 mm2.

Ah, OK. However, I thot that it would be better voltage and power if you made a single wire with 9 times as many wrappings.

 

[Zdenek Hadrbolec]

Ah, OK. However, I thot that it would be better voltage and power if you made a single wire with 9 times as many wrappings.

In the case of an electric motor, its performance is primarily defined by a unit called ampere-turn. For the flow of the necessary current, the correct cross-section of the conductor must be used. And it doesn't matter if it's one thick wire or the appropriate number of thin wires connected in parallel. Simply - as much current as possible for one thread.

 

[petertha]

Thanks friend. I use this. But I can't find it anymore because I don't know what it's called exactly. If anyone knows where to buy I would appreciate it!

Hard to tell because there have been different connectors over the years. Your picture kind of looks like one made by OS ? They can be expensive.

https://www.rc-planes-store.com/os-engines-booster-cable-single/https://www.horizonhobby.com/product/booster-cable-single/OSMG3133.html
Most RC (plane/helicopter/car) use them for remote start when the head is not easily or safely accessible. But the ones I linked from AliExpress seem to be the least expensive & acceptable quality when you require many of them. And as mentioned, you have to pay attention to the glow plug stem diameter. The OS F (F=four stroke) are slightly larger OD as are some of their other plugs, but majority of 2-stroke plugs are slightly smaller OD.

https://www.rapidrcmodels.com/remote-glow-plug-adapter-with-negative-wire-351-p.asp

 

[Bentwings]

welcome to the site . Very impressive work
The coils are wound on a classic core made of silicon sheets. Always from nine wires with a diameter of 0.4 mm, five turns each. The motor is 36 poles with 42 magnets. Or maybe 72 poles/84 magnets, it doesn't matter... :-D

 

[Basil]

Amazing work Zdenek. The custom build starter motor is very impressive.

 

[SmithDoor]

Hi to all! My name is Zdeněk, I'm from the Czech Republic and I make radial model engines. I started with small displacements, the most I built were five-cylinders with a capacity of 25 cm3, now I have two nine-cylinders with a capacity of 220 cm3 under construction, but that is too much for me. I will go back to smaller cubic volumes. My engines are always four-stroke, the smaller contents are for a glow plug, the larger ones with a spark plug. The plans are big for the future, so we'll see!

Welcome to the group

Dave

 

[kadora]

Ahoj Zdenek pekna praca .

 

[Richard Hed]

Ahoj Zdenek pekna praca .

Right. I was just saying that last week.