MSR Windpro, inverted canister

[DetachedFlake]

I hadn't heard of the Reactor's vaunted performance before I got this setup to try. Msr Windpro stove with the canister inverted to get gravity feed. BLOWTORCH! I used a heat reflector around my 1.7L titanium pot and got good efficiency (used little fuel, still fast-Sorry, no hard numbers)and simmer control with it at room temps, but this weekend on Baker at about 9500' and windy lo 30's it kept dying down and required constant attention; banging or twidling the regulator valve seemed to work, as did warming the regulator with my hand. Wondered if the stove was getting enough O2 from below to fire well, or if the reg and/or line were subject to freezing due to canister pressure dif. Got away with melting 3 liters and cooking a dinner with a 110g cartridge, but that's about all she wrote. The stove's seen recent maintenance and seems to work fine now back down in town. Anyone else mess with this kind of setup?

[The Jerk]

It’s fairly well known that canister stoves don’t like the cold and altitude. If you keep the canister warm it’s supposed to help but I just use them for fair weather and carry my dragonfly in the cold and up high. It always works.

[MarkMcJizzy]

I wouldn't use the canister upside down either. The stove is made for the liquid/gas phase change to occur inside the bottle. By turning it upside down, the phase change is occurring either inside the valve or the hose. I doubt that your stove has a regulator. This could easily burn fuel needlessly, without the proper air mix, thereby wasting fuel.

[DPS]

It’s fairly well known that canister stoves don’t like the cold and altitude.

That is an incorrect statement. Canister stoves work better at altitude. As atmospherice pressure decreases, so does the temperature of vaporization. An iso-butane cansiter stove may fail at sea level at temperatures a bit below freezing, but may work fine at much colder temperatures at 25,000 feet. This is why they work on high peaks in the Himalayas.

[counterfeitfake]

But it's still true that they don't like cold. You can search around here and the rest of the internet, and find various heat exchanger solutions people have made.

[tradhead]

Altitude is a cartridge stove's friend, cold its enemy. Good luck using one in without another source of heat to keep the cartridge pressure up if the ambient temperature is under 40 deg. F or so.

 

Expansion of the fuel requires heat which cools the cartridge which reduces the cartridge internal pressure. Without an external means of heating or pressurizing the cartridge, it's a downward spiral - more use = more cooling = less cartridge pressure = less heat.

 

If the ambient air pressure is low enough (at 7000M? and above) I've been told that this offsets the above issue, but I've never been above 15000' personally so can't say for sure.

 

I don't see an advantage for cartridge stoves over white gas for the Cascade volcanoes considering that the thermal energy per unit weight for both fuels is pretty comparable. It all comes down to stove design/efficiency for the given environmental conditions in my opinion.

[Gary_Yngve]

I have had problems with old O-rings leaking on the whitegas fuel pumps in very cold temperatures (remember Challenger '86?). The MSR manual warns against this too. If I'm using my Dragonfly in sub-freezing temps, I keep the pump/fuel in my jacket before I'm ready to use it.

[catbirdseat]

I wouldn't use the canister upside down either. The stove is made for the liquid/gas phase change to occur inside the bottle. By turning it upside down, the phase change is occurring either inside the valve or the hose. I doubt that your stove has a regulator. This could easily burn fuel needlessly, without the proper air mix, thereby wasting fuel.

We all know that Mark mean "generator" not regulator. A generator is simply a tube that passes incoming fuel over the flame, thus effecting the phase change. There are propane/butane stoves out now that are designed this way, basically like gasoline stoves.

[mountainmandoug]

I use this same set up with an MSR Windpro. It has been great down to zero, and theoretically it would work down to -40. The burner of the Windpro is the same burner as the Simerlite and it has the generator tube to vaporize liquid fuel. It does occasionally have that problem with the valve stopping up and you have to keep playing with the valve to keep it roaring. Otherwise it is so much easier to use and more efficient than white gas. There's a lot of info on this at backpackinglight.com.

[DetachedFlake]

I use this same set up with an MSR Windpro. It has been great down to zero, and theoretically it would work down to -40. It does occasionally have that problem with the valve stopping up and you have to keep playing with the valve to keep it roaring.

 

This is the problem I had. Does yours do this frequently? I've only had it out in the field once so far, but I'm reluctant to take on a multi-day because it was burning erraticaly and opening the valve to clear it means I can't accurately predict the amount of fuel I'll need. I had hoped for an even burn, at least better than an upright crtridge, which is subject to the internal pressure/temp issues. Have you (or any other cartridge users out there) played with fuel brands?

 

The Windpro does have a generator tube, so I would have guessed the gas phase change would occur there, not at the canister/valve connection. Not sure there...

[MarkMcJizzy]

We all know that Mark mean "generator" not regulator.

 

Dear know-it-all moron:

 

I was answering Flakes post

banging or twiddling the regulator valve seemed to work, as did warming the regulator with my hand.

where he was wondering about the regulator on his stove. I have a MSR canister stove, and it has a valve body. No generator and no regulator.

 

So when a canister stove is up-side down, the fuel is evaporating either in the valve, or in the hose.

[MarkMcJizzy]

 

The Windpro does have a generator tube, so I would have guessed the gas phase change would occur there, not at the canister/valve connection. Not sure there...

 

Take a gas bottle and shake it. It sloshes, because there is both gas and liquid in the bottle.

 

As you use fuel, there is less liquid, and more gas

 

Gas is lighter than liquid, hence it rises

 

A properly oriented fuel bottle (MSR stove or equivalent) will have the bottle so that the valve is at the highest point. Because of this all fuel used is in the gaseous state, and the evaporation of the liquid is confined to the bottle.

 

Any tube that passes over the burner is not generating a gaseous fuel, and is thereby not a generator.

[tradhead]

If you invert the fuel canister, the stove could have problems with cavitation at the valve. The liquid fuel will change to gas as it expands at the valve, which will make the fuel flow to the burner uneven.

 

The valve is at the top of the fuel canister for a reason.