Optimus Polaris with Polardawg in a Trangia

Discussion in 'Stove Forum' started by Tron, Jun 28, 2018.

  1. Tron

    Tron Subscriber

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    Hi,
    I just invested in a silent cap, the infamous "Polardawg" and decided to do some testing and comparisons, maybe this will be interesting to others as well. I even intend to include comparisons with some actual classic stoves...

    This is the cap, it had some dust/cleaning media inside so I decided to blow some air through it before use.

    20180626_150253.jpg

    This is the weight in grams, equals 1.5 ounces. It is smaller than I imagined.


    20180626_150701.jpg

    I decided that I would make a comparative test between the factory cap and the silent cap, so I started out with the standard setup. This is a Optimus Polaris mounted in a Trangia (I have both a 25 and a 27) with Trangias own adapter made for the Nova. I have made another opening in the Trangia lower windscreen/base for the Polaris control spindle, the large factory opening being utilised for the fuel line with its rather large connector.

    20180626_150945.jpg

    I will, rather unscientifically, measure sound level, boiling time and fuel consumption with both caps, and compare them too three other stoves I have, Coleman 550B and 400B, and a Høvik no41 (similar to Optimus 00) with a silent burner.

    Tron
     
  2. Tron

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    Sound level is measured with my Samsung S7 phone and some app. The numbers are not the actual sound level in db, you would need really expensive instruments for that, but for comparison it should be interesting enough.

    For the boiling time test I used exactly 1 litre of water (appr. 1 quart), in the same kettle for each test, the total weight checked on a scale. I also used the same temperature water, 14 degree Celsius (57 Fahrenheit).

    Fuel consumption was checked by weighing the fuel bottle/whole stove before and after boil test. I used white gas for fuel in this test, I have never run the Polaris on kerosene.

    First the original Optimus cap in a Trangia 25 with an aluminium Aloc kettle that is a little higher than the original Trangia kettle and will hold 1 liter of water.

    20180626_150938.jpg



    Rolling boil in 4 minutes 17 seconds

    20180626_155015.jpg



    Measured sound level was 75db. I think this setup is really loud, it compete with my 1950's Optimus 111 roarer in sound level.

    P1030909.JPG


    It consumed exactly 20 grams of fuel (0.71 ounces?)

    Before:
    20180626_151416.jpg


    After:
    20180626_152914.jpg
     
  3. Tron

    Tron Subscriber

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    Then it was time for the Polardawg silent cap. I removed the original cap and inserted the Polardawg. It fits easily in the burner bell but I had to rotate it a little to find the right orientation to get rid of a slight rocking of the cap in the burner. After using it a little it has settled in and "locked" itself in the bell. I primed it the way I'm used to, with a little alcohol burning for about 1 minute. I let it all burn out and then held the lighter about 1 inch over the cap and opened the valve. It lit right away burning with a blue, steady flame. The sound from the stove is not only much less, it also has a different sound to it, more like a hiss.

    20180626_154914.jpg

    20180626_161825.jpg

    Now for the boiling time: 4 minutes 11 seconds. In reality exactly the same as with the original cap.
    20180626_162516.jpg

    The sound level dramatically reduced
    P1030925.JPG
    To check the flame pattern with the silent cap I put the Polaris in the Triangle
    20180626_164831.jpg

    20180626_164450.jpg

    I also tested it with canister gas, no problems and good, blue flame both with the canister upright and inverted.

    The fuel consumption with the Polardawg was measured to 22 grams, but I failed to make an equal comparison to the original cap, the consumption with the silent cap also includes burning it in the Triangle for some minutes, and some testing of simmering etc.
     
    Last edited: Jun 28, 2018
  4. Tron

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    I did the same tests at the same time with three other stoves, I will write up all the results later, but for now just the Høvik no 41 with the silent burner.

    This is the stove burning at full throttle
    20180626_160953.jpg

    Boil test
    20180626_160937.jpg

    Sound level
    P1030915.JPG
    Fuel consumption, before
    20180626_155525.jpg
    After
    20180626_161212.jpg
    Naturally, the Høvik runs on kerosene, the Polaris test are run on white gas. Some 60 years of evolution and the difference in measured performance are only slight.
     
    Last edited: Jun 28, 2018
  5. Barrett

    Barrett New Zealand Subscriber

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    Love the boil test comparison @Tron, great detail.
    I love boil tests to compare stoves, burners etc out of interest and also as a gauge of success when I'm playing around with a stove to improve performance, with my very limited experience it is one of the easiest ways to indicate improvement for me at least.
    Hmmm do I need scales now....

    Cheers
    Barrett
     
  6. Tron

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    Now the stove I have owned the longest, and used the most, the Coleman 550B. Leaving the Norwegian army in the summer of 1990 after two years conscription and spending a lot of time attending, cleaning and maintaining Optimus 111's, I was thrilled to find a clean burning stove that was easy to light and reasonably odour free. It was my goto stoce for almost 20 years. I do still love it, even if it seldom goes backpacking these days.

    20180404_195851.jpg
    Boil test.
    20180626_154012.jpg

    Noise test.
    P1030911.JPG
    Typical for the Coleman "wafer" burners, it makes very little noise. It also simmers well. I have grown a little tired of the principle of using generators, which is a little bit of pain if you have to do maintenance on it in the field. Still, a great stove, slightly quieter than the Polaris/Polardawg, does not require preheating. Very hard to put in a Trangia set. I forgot all about measuring the fuel consumption.
     
  7. Tron

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    At last, the Coleman 400B. I have owned this stove for eight years, and used it a lot.
    20180404_193823.jpg

    Boil time
    20180626_153421.jpg

    Noise test
    P1030913.JPG
    Also very quiet. This time I remembered to put the stove on the scale, before:
    20180626_154135.jpg

    After:

    20180626_155341.jpg
    24 grams fuel consumed, rather thirsty. Still a great stove, quiet, fires very easily. If pumped hard the flames go blue almost imediatly. It also simmers very well, by that I mean with a very low, but still blue flame.
     
  8. HunterStovie

    HunterStovie United States Subscriber

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    @Tron

    Thanks for sharing. I appreciate that you took the time to do these tests.

    Mike
     
  9. Tron

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    My experience with the Polardawg silent cap are very positive, the stove is almost as easy to operate with the silent cap, I have had the occasional underburn at low power, maybe because of to little pressure. Closing the valve and quickly relighting has restored operation to normal. It burns as hot/efficently as the original "cap" and it simmers with a very low, blue flame. It seems a little more vulnerable to windy conditions, even in the Trangia. The noise reduction is phenomenal, and took away the only objection I have had to the Polaris.

    I need a good simmer, both for cooking and for making espresso. I have always read that the silent cap actually improves simmer, and at first I thought so too. But does it really? Or, what do different people actually mean when they claim that it simmers better? I is certainly very quiet, the original makes a lot of noise even when simmering. It also burns with a very steady, blue hue around the cap at the lowest setting. The original flickers and makes all kind of noises. But what I am interested in is a steady, low simmer that does not produce soot in and around the stove. And really low temperatures, like maintaining around 80 degree celsius in the food. So I decided to make a comparison, but for different reasons I had to make a comparison between an original Nova and the Polaris with the Polardawg cap. It gives an indication, at least. I pumped both stoves rather hard and boiled the same amount of water in two 1,5 liter Trangia pots-. Then I turned them way down and let them burn at the lowest setting where they still burned blue and with a steady flame. After 10 minutes of steady simmer, I had to pump both stoves a few strokes after 6-7 minutes, I measured the temperature of the water in the pots.

    The Polaris/Polardawg:

    20180627_234128.jpg
    The Optimus Nova:
    20180627_234259.jpg

    In this actual test, between a Nova with standard cap and Polaris with a silent cap, the standard Nova actually seem to simmer lower than the Polaris with silent cap. If the Polaris with the standard cap simmers the same as the Nova, then i would say that the silent cap does not simmer as well as the standard. The difference is very slight, and the silent cap simmers with a nice, calm flame and very little sound, but actually a little hotter.

    Tron
     
  10. Tron

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    Thanks for the positive comments, its been fun to do these tests, to learn what the Polardawg silent cap will do and compare the Polaris/Polardawg to some other good stoves.

    My conclusion, for my needs, is that the Polardawg is a huge improvement for my use, the original Polaris is just to loud but in all other respects a great stove. But there is always a little tradeoff to be made.

    Since I also have an Optimus Nova I am thinking that I might get a silent cap, maybe a different silent cap, for the Nova as well and maybe repeat these tests with the Nova. I also have a roarer bruner for that Høvik no41....

    Tron
     
  11. AngryDaddyBird Banned

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    Excellent test! Well done and great pictures.
     
  12. M01D United States

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    Hello Tron,

    Is there a noticeable difference in fuel consumption between the Nova & the Polaris? Optimus’s website states the Nova boils 1 liter in 3.5 minutes with a burn time of 150 minute/450mL fuel compared to the Polaris’s 3.4 minute boil time at 100 minutes/400 mL of fuel... that seems like a pretty big difference to me, which to me means carrying much more fuel in the long run to do the same task as the Nova. I’m new to liquid fuel stoves, am I looking at this correctly?
     
  13. M01D United States

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    I tried mathing but ain’t no good at that! I came up with 6 ounces/hr on the Nova & 8 ounces/hr on the Polaris if both were burning at max... I’m don’t see a need to burn either stove on high for that long, but if both were burned on low or medium heat wouldn’t the results be the same? The different BTUs & the different fuel canisters are screwing me up I think! I’m looking for a new cooking system & this fuel consumption thing is bugging me, I want something to cook real food with whether it’s frying or simmering a soup/chili, fuel efficiency is probably one of the more important factors to consider... right?
     
  14. M01D United States

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    If I were to purchase the Polaris & run it at say ¾ to match the BTU output of the Nova do you or anyone else reading this think that the fuel consumption & boil times would be similar between the two stoves? Looking forward to hearing back, thanks!!
     
  15. Tron

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    There is no discernible difference between the two. They even use the same jet, I believe. At least I have not found a source for a Polaris specific jet. Do not get hung up in published performance data from the manufacturer, you have no idea how it was obtained.What temperature of the water did they start out with? What altitude did the test take place? What kind of liquid fuel was in use? They seldom include those facts. In my test above the Trangia windshield acts as insulation and speeds up the boil time, and reducing the fuel consumed. Often a slightly reduced flame will boil water with less fuel consumed, even if it takes longer. In the field you`re ability to shield the stove from draft/wind will make a much larger difference than the make/type of stove. Liquid fuel is compact, carry enough.

    Recently I went backpacking with my wife and two kids, 11 and 13 years old ( Teenagers can eat unbelievable amounts of food...). I took a full 1 litre Optimus bottle, used the Nova in a Trangia set and made hot water, hot oat meal, bacon and beans for three breakfasts, hot chocolate and dried meals for lunch three days and dinner two nights that included frying minced meat, boiling pasta or rice and heating sauce. After dinner i made hot water for drinks. I still had maybe 1/3 of the fuel left when we got home.

    Tron