While it doesn't have a lot of mass, given the heater location on devices like the solo 2(air path), and in other kinds of hybrid heaters particularly in between the time where a draw finishes and the heater shuts off(when it does), there's always a volume of air that gets heated above the oven temperature near heater temp(because the heater always has a bigger temperature than the oven). When you pull this air into the oven air passes through the herb and easily vaporizes(through what is commonly called convection here) the compounds on top of the green matter, which generally have a lot of surface area making heat transfer easier.
On some devices the heater is capable of consistently heating the air in the chamber while on(for example solo 2 heater like showed before has a temperature above 300 ºC and its placement forces air to share a lot of surface area with it, giving it some convection power), giving them the convection like experience. The more time a specific volume of air remains near the heater, the closer it'll get to the heater temperature, meaning slower draws on heaters that are not regulated by flow result in higher temperature air passing through the plant. Some devices the heater only heats the herb chamber, by heating the walls, meaning there is no additional air being heated as you suck the heated air out. Air can never heat beyond the chamber's temperature, because it comes fresh from the outside directly to the chamber. This results in a classic conduction experience, where you need to let the system reach stability before drawing again.
Some heaters on some hybrid devices are not very powerful or very responsive. So these devices rely a lot more on conduction, because either the heater is not hot enough, has enough surface area with the air around it, or takes too long to activate when you start drawing. If the heater cannot consistently heat the air around it above(or near) oven temperature the hot air won't be enough to fully vaporize the compounds.
The ideal safe, while still providing consistent usability, scenario, which the solo 2 excels at, is having the chamber temperature very close to the ideal vaporization temperature, and bring slightly hot air in to vaporize the compounds. Since like said above air's density is small, and as a result so is the heat power it carries, it generally cannot transfer too much heat to the herb. On hybrid devices, since it only needs to slightly increase the temperature, which is already at near vaporization stable temp in the oven, the lack of heating power resulting from the lack of density is compensated by the need to transfer a smaller amount of energy for vaporization.
Full convection devices, usually have MUCH more powerful heaters, and need to heat the air far above vaporization temperature. This has some consequences. The first one is that even heating is impossible, and minor combustion is always likely to happen(I've tried to find the research that I read that backed this up, but I can't, so if someone has seen it please post it, if not, well take it as an unbacked argument because that's what it is because I may have just dreamed of it), as some parts of the plants will absorb most of the heat, particularly the ones closer to the air flux.
Each technology has it's advantages, but convection will generally have a far more targeted effect, while conduction will generally affect the overall mass inside the chamber. I would say that since air flows around the herb, while heating it, it has a higher effect on the surface compounds of the plant, which are mostly terpenes and cannabinoids, giving it the sensation of better flavor, while conduction always heats the whole plant, mixing in different compounds that do not taste as well.
For convection to reach these same compounds, it needs to heat the surface of the plant as air passes through, and then the center of the plant matter by conduction from the outside of it to the inside. Since the oven doesn't get to a stable temperature, this doesn't happen as much, so I assume most of the substances inside the green matter, remain there, as they won't reach the same temperature as a oven does.
I would assume full conduction to be the safest method, as you have guarantees that the temperature never goes above what you need it to go. Hybrids next, and convection vapes safety will be the worst of the bunch, mostly at higher temperatures as I BELIEVE small points will take enough heat to combust, even if it's not noticeable.
I believe the solo 2 has a great balance as shown in the previous graphs, the oven temperature seems perfectly stable, particularly the convection effect of it seems to be highly regulated to the point where it's effective and safe. I wish we could test this on more vapes.
PS: Important to notice, that the density of air is an effect that must be taken into account when taking a measure of heat through a thermistor, and while the relative temperature within the measured values will be correct, a thermistor not meant for measuring air temperatures needs adjutment to deliver the actual temperature at a given point(
https://www.researchgate.net/public...low_measuring_devices_for_detecting_hypopneas). Different thermistors/thermocouples also have different uncertainties in different medias.
