#170256 - 03/28/09 11:26 AM
Backpacking Stove & Windscreen Experiment
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"Be Prepared"
Pooh-Bah
Registered: 06/26/04
Posts: 2210
Loc: NE Wisconsin
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My son just did a science experiment for school in which he measured the time it took for 1 liter (actually 4 cups) of water to be heated from 53F to 190F (whole 'nother story as to why he chose 190F instead of temps closer to boiling). Note that the pot did NOT have a lid - otherwise he couldn't track the temperature as easily, though he ran one test with a foil 'lid' to see the effect.
He did this in the garage (to block natural wind) with a fan blowing on low - measuring the wind speed with a Brunton wind meter to be about 3.5 mph - a VERY light breeze at most. It was about 55F at the time.
For the experiment he used an MSR Whisperlite running clean Coleman fuel, kept the valve at the same level, plenty of time after priming/startup, and did frequent pumping to make sure pressure was not an issue. He did two runs with the windscreen on, and two with the windscreen off. Then he did one more with the windscreen on AND a 'lid' made out of foil (so he could poke the digital thermometer through it).
Halfway through he had to refill the fuel tank, but did his best to put the valve at the same setting and checked to make sure the flame was similar in size (actually the valve didn't seem to change the flame output after some point in turning).
The results were as follows:
With Windscreen: 5:23 (min:sec), 6:16, 8:00 Without Windscreen: 14:49, 17:42, 22:04*, Windscreen & Lid: 4:14
*He actually gave up after 22 minutes because he simply couldn't get the temp to go above 180 degrees.
These are real times, with only a light breeze, heating 1 quarts of water, on a mildly cold day. He actually started with the fan on high (5.5 mph), but the temperature wouldn't go above 170F without the windscreen, so he switched to the lower setting.
The 190F was selected because he ran a w/o windscreen first and he started to get frustrated after 16+ minutes, so he stopped the timing when it got to 190F and chose to use 190F for the rest of the runs.
So, if you think you don't need a windscreen, I hope you have NO wind and its quite warm outside. Otherwise, you're in trouble.
I'd strongly recommend a stove that can be used with a windscreen - or has one built in. Many of the stoves that sit on top of a fuel canister cannot use a windscreen.
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#170267 - 03/28/09 03:39 PM
Re: Backpacking Stove & Windscreen Experiment
[Re: CANOEDOGS]
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Old Hand
Registered: 10/19/06
Posts: 1013
Loc: Pacific NW, USA
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Bravo to your son for making his knowledge real, by experimentation.
fwiw I don't know of a stove type that you can't construct a wind screen for, including those that sit on top of a fuel cannister. $3 will buy you an aluminum turkey basting pan, which you should be able to cut and shape to be a reliable windscreen, which folds up for easy transportation.
Also remind your son that another screen can improve boiling points - beneath the stove itself. So cut a round bit of aluminum and put it under the stove, which with a proper windscreen may reflect heat upwards. This is particularly important if you are snow camping of course, but the same screen works well in summer too. Preserving your fuel on longer hikes is pretty darn important, the difference between a hot meal on day 5 and a cold, soaked version.
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#170269 - 03/28/09 03:58 PM
Re: Backpacking Stove & Windscreen Experiment
[Re: KenK]
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Veteran
Registered: 07/08/07
Posts: 1268
Loc: Northeastern Ontario, Canada
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Ken, Congratulations to your son for doing such a practical experiment and for sharing the results with us, nice job. I often use a Snowpeak canister stove in the field and have had trouble constructing a windscreen without heating up the tank. So I recentle purchased this new Brunton Stove Stand which allows me to seperate the stove from the tank, therefore I can use a windscreen. I have not tried it yet but the price was right (paid $14.94 at LeBaron) and it is getting good reviews on the internet. Mike
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#170307 - 03/29/09 07:31 PM
Re: Backpacking Stove & Windscreen Experiment
[Re: SwampDonkey]
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Veteran
Registered: 07/23/08
Posts: 1502
Loc: Mesa, AZ
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that is a great experiment. It seems I keep hearing how kids in school can't combine what they do as a family into what they can do for school projects. (i.e. mirroring a love for camping with science).
It has to be some school approved, teachers concept of whats important instead.
bravo.
_________________________
Don't just survive. Thrive.
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#170314 - 03/29/09 08:54 PM
Re: Backpacking Stove & Windscreen Experiment
[Re: comms]
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"Be Prepared"
Pooh-Bah
Registered: 06/26/04
Posts: 2210
Loc: NE Wisconsin
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Thanks for the nice comments about my son and his project.
He's about to turn 14, he has Asperger's Syndrome (a form of high-functioning autism that makes it hard for him to understand social rules and cues).
Both he and my daughter are junior black belts in Taikwando. Instructors from several schools in the area have seen their skill and have commented how good they are.
He's been in Scouts, loves camping, and is currently working on his last two merit badges for Eagle Scout rank and has his Eagle project selected.
Even more importantly, he's a great person.
I'm a very proud pappa.
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#170346 - 03/30/09 12:42 PM
Re: Backpacking Stove & Windscreen Experiment
[Re: Lono]
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Enthusiast
Registered: 01/12/04
Posts: 265
Loc: Stafford, VA, USA
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Take a look here http://jwbasecamp.com/Articles/KiteScreen/index.htmlNot the same as a dedicated windscreen, but probably nearly as effective if you are only blocking wind, and not channeling heat. Bill
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