Neapolitan oven - lower dome height

[fxpose]

Re: Neapolitan oven - lower dome height

I am building a lower dome 36" oven. My diameter is 36" but my final interior height will be 15.5". I have made an indespensible tool that has an adjustment for length and I had to bend the end as well. I am working on the second course now and it seems to be working out ok. As I get into the upper courses we will see if the design works.

Hi,
I have seen a few of those threaded rod, adjustable tools in use here. They seem to work. Have you calculated how much adjustment is needed on the tool for each course or are you following a template as a guide to make these adjustments?

[100million]

Re: Neapolitan oven - lower dome height

My oven is 14 " height on inside dome and 29 wide

[Neil2]

Re: Neapolitan oven - lower dome height

A hemisphere focuses the heat at one point. An ellipse at two points, or in the case of an oven in a ring.

[dsgreco]

Re: Neapolitan oven - lower dome height

I have seen a few of those threaded rod, adjustable tools in use here. They seem to work. Have you calculated how much adjustment is needed on the tool for each course or are you following a template as a guide to make these adjustments?

I am following a template.

[shuboyje]

Re: Neapolitan oven - lower dome height

But a sphere section creates a circle, and if designed right that circle can cover almost the entire oven floor. Now mind you none of this actually matters because our rough matt yellowish fire bricks are not prefect emitters, and they do not produce perfect straight waves of radiation, they create diffused radiation like the sun on a cloudy day. If they did produce perfect radiation which oven would cook more even? Obviously the low dome oven with it's heat focused evenly over almost the entire oven floor. The hemisphere has many advantages as it is easier to build and more stable on top of the fact that the design has been proven many times over in great functioning ovens, but the even heat from a single point idea that gets thrown around here is nonsense. If that was the case you would have one hot spot in your oven and the rest would lose heat rapidly. The fact that doesn't happen shows the radiation in our ovens is highly diffused.

A hemisphere focuses the heat at one point. An ellipse at two points, or in the case of an oven in a ring.

[david s]

Re: Neapolitan oven - lower dome height

Shuboyje,
I think you are are correct in yor assessment of the situation regarding the heat radiation. Probably the main advantage of the hemisphere apart from its inherent stability is its superior shape as a combustion chamber. Remember the Chrysler hemi heads?

[Glosta]

Re: Neapolitan oven - lower dome height

David S: I am wrestling with the optimal door height to dome height ratio. All over FB forum 63% is recommended & builders seem to desire a low dome height. One of your past posts contends "THE MOST EFFICIENT COMBUSTION CHAMBER IS THE HEMISPHERE" I am building a 42 inch Pompei with a 20 x 12 door entry. I kept the first three rings flat and vertical. However I am now on the sixth ring and the dome is only pitching in to a 39 inch diameter. I am raising each ring about 1/2 inch at the outside. But it appears at this rate I will end up with a higher dome--maybe 28 inches? Will this pose a cooking or heating problem? The FB manual states there are many WFO with higher domes. How is the performance? Why is there a repeatedly stated desire for the low dome height?? Should I agressively increase the chain pitch with a 3/4 inch rise at outside?? Any input would be appreciated. Thank you.

[fxpose]

Re: Neapolitan oven - lower dome height

Glosta, what are you using as a gauge to pitch each course, such as the I-tool or a form of some sort? The entry and dome height should both be predetermined for the most part, first by deciding on dome height, then determining your entry height, at least before you start laying courses.

George

[Glosta]

Re: Neapolitan oven - lower dome height

George Thank you for the quick reply. Yes I am using an I-tool. Its the magnetic door stop attached to threaded rod with turnbuckle for adjustment. It produces fairly consistent measurements but the spring loaded magnets introduce some slop.

Door height is 12 inches, so I was shooting for the 22 inch interior dome. My soldier course consisted to three chains laid on the flat, vertically with no pitch. I should have started the pitch on second chain. This would have picked up ten degrees. I was initially using 3/8 inch wedges but pitch was not rising quick enough. This morning used a 3/4 inch wedge on sixth chain. This looks better. I will probably cut a 1 inch pitch into the next chain to avoid large mortar joint. Thanks again for the help.

[fxpose]

Re: Neapolitan oven - lower dome height

Glosta, if you are shooting for a 22" dome you can cut out a dome profile template out of cardboard, for instance, and make adjustments to your I-tool to the template at every course level. By following the template you're guaranteed to end up at your desired dome height, or at least come very close.

George

[karl]

Re: Neapolitan oven - lower dome height

Remember too that the most efficient combustion chamber is the hemisphere. Any departure from it is a compromise. It's like boats, there is no perfect form. The form you choose is a compromise to suit your needs.

For pizza it would be a flat dome?

[dmun]

Re: Neapolitan oven - lower dome height

For pizza it would be a flat dome?

A LOT of us here are successfully cooking pizza in hemispheric domes.

I think there's a certain amount of Neapolitan snobbery in the flat dome. They make a good pizza, but the horizontal forces create more of an engineering challenge than the hemisphere.

[karl]

Re: Neapolitan oven - lower dome height

Hi dmun

Sure, me too. Proves that "most efficient" can be interpreted in many ways. Most convenient, least challenging, heat up time, best baking result ....... From the perspective of even heat distribution to a pizza the flat dome intuitively should give the best (most even) result.

karl

[Tscarborough]

Re: Neapolitan oven - lower dome height

Only if there is no fire and you place the pizza directly below the keystone.

[Neil2]

Re: Neapolitan oven - lower dome height

"I think there's a certain amount of Neapolitan snobbery in the flat dome."

Yes indeed. Those of us with elliptical ovens (dome height = 85% to 90% of diameter) defiantly look down with scorn at you hemisphere fellows.