JetBoil wind tests

[Tony]

There has been some recent discussion about JetBoil stoves in the “what stove do you use” thread one of the things that keeps coming up is that some people have claimed that JetBoil stoves are good in a windy situation, so I thought I would fire up the test bench and do some wind tests to see if I could quantify if the JetBoil is in fact good in windy conditions, for part one of these test I used an original modified JetBoil Personal Cooking System (PCS). And for part two I used the same burner but with the Group Cooking System Pot.


Testing setup

Test procedure.
For these test I used the JetBoil stove in a remote canister configuration, this was done as the stove is lower so I could use a variety of windshields.


JB stove used as remote canister stove

The stove was placed on my test bench with a small pedestal fan placed a meter away, I placed my old Vane Anemometer on the bench and tested wind speed which was measured at around 12kph (note, the wind speed feels faster that 12 kph but I could be wrong) I then attached the stove to the canister and took note of weight, measured 500g of water in pot, replaced lid.


Test with MSR windshield

I then placed stove on test bench, placed thermistor in pot at 1 cm from bottom, started data logging program and at 10 second started stove and adjusted to a high flame setting, when water temperature reached 95º stopped stove, removed pot and re-weighed canister, noting the new weight. From logged data start temp was noted and fuel used was normalized to grams of fuel used per 80º (g/80C)


Using Caldera cone windshield

The tests
The first test was with no windshield and no wind, (no W no WS) this is used a base line figure. Results, fuel per 80ºC = 6.1 g

The second test was with the fan on but no windshields (W no WS). Results, fuel per 80ºC = 8.2 g

The third test was with fan on and using an old MSR wind screen (W MSR WS) which was placed completely around and secured together with a clip. Results, fuel per 80ºC = 7.4 g

The fourth test was using a Trail designs Caldera Cone windscreen (W CC WS) , this windscreen is designed for a BPL Ti 550 pot and was too small to fit over the JB pot with the cozy on it, so I placed the windscreen as best as I could around the pot with the gap opposite the fan, the fuel line came out this gap. Results, fuel per 80ºC = 6.9 g

Comparison of PCS wind tests
Below is the heating rate graph, the fastest boil (pink line) is the test with no wind the slowest is the test with wind but no windshield.


Wind tests heating rates

Discussion of results.
First I wish to point out that these tests are not what I would call scientific, I only did one run per test and with canister gas stoves they are very hard to adjust to repeat runs, but there is a trend that fits in with what I was expecting.

The result clearly show that there is a reduction of efficiency with the introduction of wind, and that a windshield does make a difference, the tests also show that the JetBoil PCS stove is not too badly effected by moderate winds, I was actually surprised how little loss of efficiency the JB system has with no windshield., from past tests with a normal upright stove with no windscreen there was a much high loss, I am also surprised with this system what little difference a windshield made to the efficiency and these test the CC windshield was only marginally better that the MSR windshield.

Part 2, JetBoil Group Cooking System Pot (GCS). The GCS's heat exchanger is fully exposed and I suspect it would be more vulnerable to wind.


JetBoil GCS remote canister setup

Testing method
These test were done much the same as the PCS, I decided to do this to try and get better consistency in the tests, to do this I put a adjustable valve on the canister and ran the JetBoil stove until the flame at a high level and was stable I then only used the valve on the canister to turn the stove on and off. My STD 0.5 liters of water were used. The wind speed measured was around 12-15 kph.


GCS stove with old MSR windscreen

Results
Test 1, GCS pot and remote canister JetBoil stove, no wind and no windscreen, Fuel used in grams per 80ºC = 5.0g
Test 2, wind with windscreen, stove was lit then windscreen placed around stove, then fan turned on. Fuel used in grams per 80ºC = 5.5g
Test 3, wind, no windscreen, During this test it was obvious that it this system is greatly effected by wind and to raise the water to 95ºC was going to take some considerable time and fuel, I stopped the tests at the same time as the no wind test and as the heating rate is usually linear I extrapolate the results.
Fuel used in grams per 80ºC = 25.4g


Comparison of GCS pot wind tests


JB GCS wind tests heating rate, note the flate heating rate of the wind no windshield

Heating rate graph, pink line no wind/ no windscreen, blue line, wind/windscreen, yellow line wind/no windscreen
Discussion of results.

As can be seen from the fuel used in the wind/no windscreen test the GCS stove efficiency is affected quite a lot by wind but the use of a windscreen does improve the efficiency and possibly if the windscreen is setup properly wind may have no effect, the difference between the results of the no wind and wind/windscreen tests is very small this difference could be considered in normal testing error.

Conclusion. GCS
Unlike the PCS stove the GCS stove system efficiency is greatly affected by wind but the use of a good fitting windscreen can greatly improve efficiency to the point that the wind may have little or no effect.

Conclusion PCS vs GCS pots
As can be seen in a windless situation or when used with windscreens the PCS system is less efficient that the GCS pot system but when there is some wind around the PCS system is far superior. One thing these tests show is on most stove systems the importance of a good windshield.
I have not tested the new JetBoil Sol cooking system, I am considering getting the To version which is similar in weight to my one liter Aluminium pot, Kovea Supalite stove and windscreen.

Tony

[rucksack]

Tony, thanks very much for sharing these results. Do you think that the higher fuel consumption with the JetBoil PCS is at least partly due to the smaller pot, and subsequent heat loss up the sides of the pot? I was reading somewhere that pots with diameters less than about 14cm are susceptible to this. And with the larger JetBoil GCS, would you put the considerably higher fuel consumption principally down to the fact that the much larger pot in the GCS presents a so much greater surface area to the wind?

rucksack

[Tony]

Tony, thanks very much for sharing these results. Do you think that the higher fuel consumption with the JetBoil PCS is at least partly due to the smaller pot, and subsequent heat loss up the sides of the pot? I was reading somewhere that pots with diameters less than about 14cm are susceptible to this. And with the larger JetBoil GCS, would you put the considerably higher fuel consumption principally down to the fact that the much larger pot in the GCS presents a so much greater surface area to the wind?

rucksack

Hi Rucksack,

Some good questions

Do you think that the higher fuel consumption with the JetBoil PCS is at least partly due to the smaller pot, and subsequent heat loss up the sides of the pot?

Yes, pot size is important, on some previous test a non flux ring pot would have to be at least 250 mm plus to be as efficient as the GCS pot, I will have to go back to some results to find a size to compare to the PCS pot.

I was reading somewhere that pots with diameters less than about 14cm are susceptible to this.

all pots loose heat up the sides, 14cm is a good size for a pot, my tests show that a larger pot is generally more efficient but once you get to a certain size, any effciency gain is offset by weight gains, I have not seen any efficiency losses with larger pots.

And with the larger JetBoil GCS, would you put the considerably higher fuel consumption principally down to the fact that the much larger pot in the GCS presents a so much greater surface area to the wind?

No, the higher fuel consumption was due to the less protected flame, this can be easily seen and is the same with the Kovea Supalite stove under the GCS pot.

Tony

[rucksack]

Thanks Tony.

Very interesting numbers ... and useful too.

rucksack

[photohiker]

The result clearly show that there is a reduction of efficiency with the introduction of wind, and that a windshield does make a difference, the tests also show that the JetBoil PCS stove is not too badly effected by moderate winds, I was actually surprised how little loss of efficiency the JB system has with no windshield., from past tests with a normal upright stove with no windscreen there was a much high loss, I am also surprised with this system what little difference a windshield made to the efficiency and these test the CC windshield was only marginally better that the MSR windshield.

Hi Tony,

This is good stuff.

Thanks for running these tests. From my limited use of the Sol, I can only agree with your observations and surprise at how little the wind upsets the jetboil. The amount of wind in my vestibule would be less than your fan creates, but still enough to upset my snowpeak ti stove - which is why I always used a windshield with that stove.

[Tony]

Hi Tony,

This is good stuff.

Thanks for running these tests. From my limited use of the Sol, I can only agree with your observations and surprise at how little the wind upsets the jetboil. The amount of wind in my vestibule would be less than your fan creates, but still enough to upset my snowpeak ti stove - which is why I always used a windshield with that stove.

I enjoy doing these types of tests, these tests are part of a larger series of tests that I am doing on windscreens.

I am seriously thinking of getting the JB Sol Ti, I really need more stoves. If JetBoil want to send me one for testing I would be more than happy to do a review to post on BA.

Tony

[gayet]

On the JetBoil and gas cannisters in general, has anyone tried refilling gas cannisters? I found a bit on BPL under a discussion on JB Sol ti on refilling cannisters and it seems like a potentially environmentally friendly option as well as potentially cheaper.

http://www.backpackinglight.com/cgi-bin ... d_id=44805

Would be interested in others thoughts....

[Tony]

On the JetBoil and gas cannisters in general, has anyone tried refilling gas cannisters? I found a bit on BPL under a discussion on JB Sol ti on refilling cannisters and it seems like a potentially environmentally friendly option as well as potentially cheaper.

http://www.backpackinglight.com/cgi-bin ... d_id=44805

Would be interested in others thoughts....

Hi gayet,

Refilling disposable canisters is illegal and should not be done, if not done properly eg over filling it can be very dangerous.

That said a few people do refill canisters, I have read that it is possible to do only a few times per canister before the valve might leak. The BPL article has some information on where to get the appropriate fittings, I made mine.

Tony

[gayet]

Ok I understand the illegality and dangers inherent in refilling something that may not be intended to refill, BUT it obviously is possible. I noted the info on obtaining the necessary fittings - preferred the heavier more robust option to the "lightweight carry it with you" version.

At this stage I don't actually own a stove of any kind but have been reading the various discussions and am leaning towards the JB. There is a long way to go before I get near attempting to refill cannisters. But I'll file it away for future reference.

Thanks Tony

[Ticklebelly]

Thanks for making the effort and posting useful results. I don't have a Jetboil but I will be doing some more work on my windshield system.

Ticklebelly

[hikin_jim]

A very good and very helpful set of tests, Tony.

Those numbers, significant though they are, would show an even greater disparity between wind/no wind if a more typical canister stove were used. Quite interesting and a good reminder to use a windscreen.

HJ

[jimqpublic]

Tony-

I see you have the canister inverted in the first PCS photo. Have you modified the pcs with a vaporization loop? If so do you have a write up on the mod? I just acquired a Brunton stove stand and would like to be able to use the PCS in cold conditions (-10C)

Thanks

Jim in California

[Tony]

Tony-

I see you have the canister inverted in the first PCS photo. Have you modified the pcs with a vaporization loop? If so do you have a write up on the mod? I just acquired a Brunton stove stand and would like to be able to use the PCS in cold conditions (-10C)

Thanks

Jim in California

Hi Jim,

Yes I have modified my JetBoil PCS by adding a pre-heat tube, this was not easy to do, I did a writeup when I first did the mods and posted on BPL JetBoil mods I have since improved the modification, the modification requires a reasonable level of metal working and welding skills.

I am planning on getting a Sol soon and do the same modification.

Tony

[hikin_jim]

Hi, Tony,

If you do get a Sol, I'd be very curious to know the jet size, and if you had time, how that jet size compares to some of your other gas stoves. My guess (based on Stuart Robb's BPL post) is that the Sol's jet is slightly larger than average and that difference in size accounts for how the regulator valved stoves were able to out perform other stoves in Will Rietveld's testing on BPL.

HJ

[Tony]

Hi, Tony,

If you do get a Sol, I'd be very curious to know the jet size, and if you had time, how that jet size compares to some of your other gas stoves. My guess (based on Stuart Robb's BPL post) is that the Sol's jet is slightly larger than average and that difference in size accounts for how the regulator valved stoves were able to out perform other stoves in Will Rietveld's testing on BPL.

HJ

Hi HJ,

It probably will be a while before I get a Sol but when I do I will measure the jet size and post it.

BTW the Sol has just been released in Australia but has not arrived in any shops in my home town yet but when it does the Sol Al is will cost A$209 and the Sol Ti will cost A$250, I can get the Sol Ti from the US for around US$120.

Tony

[Ent]

Hi Tony

My Ti (almost?) cost $99 from the States. Thanks for the test. While as you say, they are more a guide than a definitive statement they are useful to see how wind effects the performance. I noticed when in the Walls area a very lazy wind did not knock the stove's performance around too much while a Primus Gravity definitely would need a wind shield in similar conditons. Only thing I find is on a very low settings the TI will blow out.

Cheers.

[hikin_jim]

It probably will be a while before I get a Sol but when I do I will measure the jet size and post it.

Excellent.

BTW the Sol has just been released in Australia but has not arrived in any shops in my home town yet but when it does the Sol Al is will cost A$209 and the Sol Ti will cost A$250, I can get the Sol Ti from the US for around US$120.

Good night! that's expensive. Where does all that mark up go? I suppose distribution. PM me if you need help getting one from the US.

HJ

[Tony]

Hi Tony

My Ti (almost?) cost $99 from the States. Thanks for the test. While as you say, they are more a guide than a definitive statement they are useful to see how wind effects the performance. I noticed when in the Walls area a very lazy wind did not knock the stove's performance around too much while a Primus Gravity definitely would need a wind shield in similar conditons. Only thing I find is on a very low settings the TI will blow out.

Cheers.

Hi Ent,

Thanks for that info, I plan to only boil water for dehydrating meals with my Sol,so I will be working out the optimum setting, and I will be designing a windscreen for it.

Tony

[Tony]

Good night! that's expensive. Where does all that mark up go? I suppose distribution.
HJ

Hi HJ,

The problem is that a lot of gear is brought into Australia through importers, this normally increases the price dramatically, I have seen shop price lists where the shop pays more for a product from the importer than you can purchase the same product for over the counter. The retail shops here usually have a 100% markup which puts the price up a lot and is the reason a lot of us get gear from the US.

Sea to Summit are the JetBoil importers here, one problem we have is that when we find a US retailer willing to sell to us Australians, if the local importer hears about it as they often do through forums, they make the US manufacturer stop the retailer selling to us.

PM me if you need help getting one from the US.

Many thanks, I might take you up on the offer.

Tony