Following on from the hanging stoves I fired up the test bench on the weekend and ran some wind tests on the JetBoil stove that I have modified for the hanging stove.
Part of the design of my JB hanging stove is that it does not have to be hung, it can be used as a normal remote canister stove, for these test I used the stove as a 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 12kph 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.
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)
The first test was with no windshield and no wind, 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.
Results, fuel per 80ºC = 8.2 g
The third test was with fan on and using an old MSR wind screen 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, 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
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.
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, I am 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.