In response to my own question and after doing some research and talking to one of the MSR stove engineers at the OR Show, I found out some interesting information:

The Reactor is a marvel of engineering. All the ingredients need to be there in order for it to perform as advertised. In my research, I found that the metal foam is one of the most efficient radiant burner materials on the market. What it allows the stove to do is produce heat throughout the entire surface of the foam much more efficiently and at a higher temperature than with an open flame or by using any other material such as ceramic. Because of this revolutionary foam, the Reactor can produce 9,000 btu at 11 psi. Thus the internal pressure regulator is needed to maintain the amount of psi allowed for optimum cold weather performance. Pretty ingenious! The most amazing thing is that this is only one of the engineering challenges faced. The fact that it is 100% windproof (100% primary air) and by using radiant and convective heat, the thought put into this stove is impressive.

The metal foam also heats up almost instantaneously and cools almost as fast. Although not the lightest nor, as Roger has outlined, the best stove for reduced carbon monoxide output, it is one of the best stoves in serious weather conditions often found in the backcountry. After owning one for a few months and using it in some pretty bad conditions, I am convinced that it is one of the coolest (no pun intended) pieces of gear I own!

In the Wind Rivers near Island Lake in Titcomb Basin, I used the stove to boil water inside my tent for both my food and hot chocolate. The tent I was using was the Hilleburg Akto (small one-man tent) and only used the stove long enough to boil the water. I didn't feel any adverse effects such as headaches, nausea, etc. that often accompanies high CO levels.

Edited by jasonlivy on 01/31/2008 14:35:07 MST.

> The Reactor is a marvel of engineering.
I do not dispute this. I understand the concept behind the 'reactor' - a form of fluidised bed combustion. I do dispute whether it is the 'right thing' for walkers.

> it is one of the best stoves in serious weather conditions often found in the backcountry
Sorry, but I strongly disagree.

For a start, it will fail in the snow. Well, actually, it's the canister which will fail once the ambient gets sub-freezing. Granted, if you use an iso-butane/propane mix you can push the canister down a bit below freezing, but the idea of relying on a stove whose canister can freeze up in the snow is, to my mind, foolish.

Secondly, 'in serious weather' you do not want to be cooking outside. Get real. But cooking inside your tent with this stove has to be one of the most hazardous occupations around. I can only hope you had a LOT of ventilation going on at the time.

And finally, there are far better stoves available for use in serious weather. Why run the risks?

And yes to all: there is a review of the revised production version of the Reactor in the near pipeline. The CO levels have been improved - but they are still dangerous imho.

Cheers
Roger Caffin

Edited by rcaffin on 01/29/2008 02:14:21 MST.

Roger,
is there an opportunity to discuss the press regulator thing in the upcoming review? What it is, how it works, is the pressure regulator in the Reactor different or does the overall construction of the Reactor influence the functioning of the regulator, what it means or doesn't mean for the use of the stove in cold temperatures?

And that taking into consideration what Jason already mentioned (normal stoves need 65 PSI, Reactor supposed to need only 13 PSI, the radiant bed which needs only 11 PSI, ...) and how the pressure drops inside the canister from about 75 PSI when full down to ??? when almost empty.

A number of reviewers have mentioned the great capability of the Reactor to function when temperatures are below 0°C. I don't know the exact conditons but it seems in contrast to what you are saying.

Yeah, the low pressure requirement will allow the stove to function down to a much lower temp than standard canister stoves, as well as eke out more of the fuel. However, there's still a limit imposed by the mixture of fuel used.

>For a start, it will fail in the snow. Well, actually, it's the canister which will fail once the ambient gets sub-freezing. Granted, if you use an iso-butane/propane mix you can push the canister down a bit below freezing, but the idea of relying on a stove whose canister can freeze up in the snow is, to my mind, foolish.

Sorry, but I strongly disagree due to my own personal experience. I've had this thing down to 10°F (according to my Suburu Outback's temperature gauge) with 20 mph winds and still watched it (along with about 20 other people) boil a liter of water at 3min. 30 sec. This is far below freezing using a half-empty isobutane propane canister while it was in a pile of snow. I was in Rocky Mtn National Park at a snowshoe demo. I feel comfortable using it down to about 5°F.

I would agree in very severe weather (below 0°F) I would opt for a white gas/multi-fuel stove, but anything above that up to freezing, the Reactor is the only canister stove that I would feel ok using. I've been in some pretty bad weather on the Sawtooths in Idaho, Wind Rivers in Wyoming, Uintas in Utah, and other places where traditional canister stoves wouldn't work. The Reactor is a whole other story.

Have you had a chance to use it outside the lab (not trying to be cute, but want to know if you, in your tests, have used it in "real world conditions")?

Edited by jasonlivy on 01/29/2008 15:32:23 MST.

According to MSR, the pressure regulator is no different that what you would find in a backyard barbecue, just smaller. The big difference is the new metal foam that allows the stove to reach 9000 btu with only 11-12 psi. This is the "magic" of the Reactor, again according to MSR. Without this special foam, the internal pressure regulator wouldn't do anything, kind of like the Gaz Twister (didn't do much for this stove). This is also why you don't see it in any other backpacking stove.

The special burner is the key that allows the Reactor to do what it does, that is to overcome the effects of the pressure canister due to cold and low volume. The other major benefit the Reactor brings to the table is that it uses primary air only thus making it completely windproof (the worst enemy to any backpacking stove). And the radiant/convective pot also increases it's efficiency although it does create more CO emissions as a result.

It sounds like to me, Roger, though I totally agree with his CO emissions findings, has based whether or not he approves of the Reactor totally on the basis that it puts out a large amount of CO at low volume. Though important and something we all need to know, this stove's benefits should be also considered. It appears to me that there is a large amount of bias in his remarks IMHO.

Edited by jasonlivy on 01/31/2008 14:31:31 MST.

>Secondly, 'in serious weather' you do not want to be cooking outside. Get real. But cooking inside your tent with this stove has to be one of the most hazardous occupations around. I can only hope you had a LOT of ventilation going on at the time.

Again, I disagree here. There are other dangers involved with using your stove in a tent. If, for instance, I understand the concerns with the amount of CO emissions it puts out, then I will take the needed precautions (more ventilation, only use at full volume, etc). I think a bigger threat is burning down the tent when priming. I have, on several occasions, cooked my food in pouring rain, blizzards, etc. outside my tent. The fact that I need only about 3 minutes with the Reactor makes it doable.

Due to the massive rainstorm that hit me, I completely buttoned up my tent. As most people know, the Akto isn't the best ventilated tent around, but, again, I felt no adverse effects. I know how subtly carbon monoxide can effect a person and I was fully aware of this while using the stove (I'm always concerned about this no matter what stove I'm using). If I find I am getting headaches or feeling sleepy, I immediately turn off the stove. I felt no such thing (I was operating it at full volume for the quickest boil).

I do plan on making sure that I am very careful (more so now due to your report) with the Reactor while using it in my tent, but due to my experience, I plan on continuing to use it in a tent when necessary. I try not to use it there as much as humanly possible, but as you said, let's get real. There are times (very few times) when there is no other way.

Edited by jasonlivy on 01/31/2008 11:18:43 MST.

Post Deleted.

Edited by jasonlivy on 01/31/2008 13:00:34 MST.