View Full Version : MSR Pocket rocket above 9500 ft. Will it work
Does any one know if the pocket rocket will work above 9500 ft with efficiency? Or should I consider the whisper light?
Most definitely will work. Alcohol stoves too for that matter.
Heck..they use canister stoves on Everest currently (and leave behind lots of the empty fuel canisters! :O) (http://www.himalayaexpeditions.com/garbage_deposit.php)
HooKooDooKu
06-02-2014, 12:28
The problem with canister stoves is that if the fuel becomes too cold, the fuel with not vaporize. No vaporization, no fuel reaches your stove to burn.
All things being equal, a canister stove will work "better" at higher altitudes because the lower air pressure means that the fuel can continue to vaporize at cooler temperatures. Based on charts I can find at Zen Stoves (http://zenstoves.net/Canister.htm), at an altitude of 9,500', the fuel will still vaporize at temperatures about 15º cooler than at sea level. Of course that effect if somewhat offset by the fact that the higher you go, the cooler the temperatures.
evyck da fleet
06-02-2014, 20:52
Yep. Had no problem cooking with a pocket rocket while camped above 11,000 on the JMT including one night that went below freezing. Oddly, I couldn't get it to light in April in GA on my AT hike when it was below freezing. I wondered if that was because of the temp and because it was a near full canister.
Wise Old Owl
06-02-2014, 20:55
The problem with canister stoves is that if the fuel becomes too cold, the fuel with not vaporize. No vaporization, no fuel reaches your stove to burn.
All things being equal, a canister stove will work "better" at higher altitudes because the lower air pressure means that the fuel can continue to vaporize at cooler temperatures. Based on charts I can find at Zen Stoves (http://zenstoves.net/Canister.htm), at an altitude of 9,500', the fuel will still vaporize at temperatures about 15º cooler than at sea level. Of course that effect if somewhat offset by the fact that the higher you go, the cooler the temperatures.
The mix of fuels is designed to work at higher altitudes. The preheat copper or brass pipe is not there but it still works. It just takes longer.
HooKooDooKu
06-03-2014, 11:05
Yep. Had no problem cooking with a pocket rocket while camped above 11,000 on the JMT including one night that went below freezing. Oddly, I couldn't get it to light in April in GA on my AT hike when it was below freezing. I wondered if that was because of the temp and because it was a near full canister.
Perfect example of changes in altitude affecting the fuels boiling point.
While a full vs. near empty canister effects things as well, a 10,000' change in elevation has a much greater impact.
As stated at Zen Stoves (http://zenstoves.net/Canister.htm):
For a stove to operate, you need to have enough gas pressure above the atmospheric pressure to force enough gas out of your stove to stay lit
That same web page shows a chart on how elevation changes the boiling point of canister fuels... and an elevation difference of about 10,000' makes for a boiling point difference of about 20º.
So lets say a typical canister stove will easily operate at temperatures down to 40º in the North GA mountains. Anything lower and you might have to start taking extraordinary measures to keep the stove operational. You can take that same stove to an elevation of 11,000' along the JMT and it will easily operate at temperatures down to 20º before you have to start taking extraordinary measure to keep the stove operational.
It's sort of like how water will boil at 212º at the beach, 200º in Denver Colorado, and 190º at 11,000'. The only difference is rather than that boiling point vary around a temperature of 200º for water, the boiling point in the area of 32º for canister fuels.
Of course this is all being very simplistic as there are numerous variables at work when a canister stove is operating so the temperatures you can make a canister stove operate might be different than this simplistic example.
colorado_rob
06-03-2014, 11:15
The problem with canister stoves is that if the fuel becomes too cold, the fuel with not vaporize. No vaporization, no fuel reaches your stove to burn.
All things being equal, a canister stove will work "better" at higher altitudes because the lower air pressure means that the fuel can continue to vaporize at cooler temperatures. Based on charts I can find at Zen Stoves (http://zenstoves.net/Canister.htm), at an altitude of 9,500', the fuel will still vaporize at temperatures about 15º cooler than at sea level. Of course that effect if somewhat offset by the fact that the higher you go, the cooler the temperatures. this is exactly right, to reiterate: higher altitude HELP canister stoves, it's only the "cold" that makes them work less that great (again, repeating Hookoo...). but it has to be pretty cold to be a problem; we use upright canisters down to freezing successfully, then inverted canisters in the bitter cold.
then inverted canisters in the bitter cold.
For all but possibly large group use, seems canister stoves have taken over from white gas as the stove of choice for winter use too....
colorado_rob
06-03-2014, 12:34
For all but possibly large group use, seems canister stoves have taken over from white gas as the stove of choice for winter use too.... My last really high (>20,000') mountain climb was in 2012 (Denali), and "back then", liquid gas stoves were still in the slight majority, like when melting snow was the primary source of water. Some groups took both; say, a team of 4 or more would take a white gas stove for heavy work, plus a canister stove for quick hot drinks. I'm still on the fence; seems my trusty old whisperlite is STILL my go-to stove for high, cold climbs; the fuel efficiency seems better, hence lighter overall. Close call though.
HooKooDooKu
06-03-2014, 13:00
then inverted canisters in the bitter cold.For all but possibly large group use, seems canister stoves have taken over from white gas as the stove of choice for winter use too....
To run an inverted canister, you need a "remote" canister stove such as the MSR WhisperLite Universal (or the now discontinued MSR Simmerlite).
But those stoves are much more heavier than the screw-on canister stoves like JetBoil, MSR Pocket Rocket, or (my personal favorite) Snow Peak LiteMax.
So for warm weather, I'm going for light-weight screw-on canister stove.
But when it comes to cold weather, I still switch over to white gas. There's really not much weight savings (especially if you need less that a full bottle of fuel) in a remote canister stove compared to a white gas stove, and with white gas, all worries of cold weather disappear.
I'm still on the fence; seems my trusty old whisperlite is STILL my go-to stove for high, cold climbs; the fuel efficiency seems better, hence lighter overall. Close call though.
Indeed. For me, I just really can't justify another stove. It is not even the money as much as the "do I need yet more crap ????"
So I stick to the white gas stove. Esp for winter trips in a group. White gas stoves seem to a be bit better for, as you aptly put it, heavy work.
But I also see a lot of people using inverted stove for winter use, too.
If I did not already have a WG stove, I am honestly not sure which way I'd go!
There's really not much weight savings (especially if you need less that a full bottle of fuel) in a remote canister stove compared to a white gas stove, and with white gas, all worries of cold weather disappear.
I think people like them for convenience vs a WG stove rather than weight savings. Using a WG stove is a bit of a learning curve vs a canister.
ps. The Simmerlite is a WG stove. I think you may be thinking of the Windpro?
http://www.rei.com/product/830343/msr-windpro-ii-backpacking-stove
I believe it is still made..or at least common enough to buy.
These fellas have the science covered, but just as an anecdote I used one without incident for hot chocolate at Muir Pass (11,955 ft), Forester Pass (13,153 ft), and the summit of Mt. Whitney (14,505 ft). I can't say for sure how the efficiency was affected, but the canister life was not significantly shorter.
So you should have no problem using it. And you may not even notice a difference, unless you are tracking fuel usage really closely.
PS, I should mention this was all in summer with temps nowhere near freezing. As others have mentioned, the temperature can be the limiting factor.
HooKooDooKu
06-04-2014, 15:38
ps. The Simmerlite is a WG stove. I think you may be thinking of the Windpro?
I believe it is still made..or at least common enough to buy.
Thanks for the correction... yes indeed I was thinking about the Windpro. At first I couldn't find the Windpro on the MSR website, and they have indeed discontinued the Windpro... but its been replaced by the stove you pointed to... the WindPro II. MSR Lists it under there "Gourmet Cooking Stoves"... not sure why.
Of course about the only difference I see between the original WindPro (one of which I have) and the WindPro II is the stand to allow you to hold the canister inverted.
I can't say for sure how the efficiency was affected, but the canister life was not significantly shorter.
Again, referencing the Zen stove website, a canister (and actually all fuels) is less efficient at high altitudes because water boils at a lower temperature. As such, your food will take longer to cook, and therefore should cause you to use more fuel to cook the food compared to lower elevations. Of course the truth behind that depends upon exactly how you use the stove. After all, if all you do is boil some water and pour it in a bag to re-hydrate a meal, your water will boil sooner (using LESS fuel) and will simply take longer to re-hydrate.