The Primus ExpressLander VF is not much of a stove in size but in quality. It's been engineered for light weight backpacking. It's not a classic. It has the usual quality of which Primus has always delivered. It is definitely small. It would not be ideal for more than one person to cook for since weight instead of high output was the concern. Other than lacking high output, this stove is actually a muti-fuel stove. As a test, I ran Coleman fuel and then proceeded on to "the other white fuel", kerosene, which did a little better job. The numbers were a bit disappointing, but then, maybe the conditions were not ideal. I used a brass kettle, with starting water temperature of 43F for 1 liter. The ambient temperature was recorded at 18F at 4600F elevation. So these factors may have contributed to the stove's performance. I also did not use any type of windscreen, which would contribute to better performance. No wind was blowing. For Coleman Fuel, running the stove at maximum, I achieved an average score of 18 minutes to reach boil. I blame the jet size for the slow time. The unusual thing about this stoves is that it is quite small but has been designed to burn multiple fuels so the aperture of the jet has to be at some happy medium to allow both to burn. I believe any larger of a jet, wouldn't not allow some heavier liquids to burn. Kerosene did a little better at 12 minutes to boil with same conditions. The stove is capable of using white gas, unleaded gasoline, kerosene, and other equivalent fuels, so I'm guessing diesel would also be included on the list. With the jet size, I'm pretty sure that it won't be able to burn alcohol well. There are probably jet replacements but haven't seen them. The stove with the installed jet burns better on kerosene. I took a picture of the output rating and it talks about the stove as being able to put out about 8000BTUs whether or not it is gas or kerosene, but I believe that these claims must be somewhat exaggerated. Other than the above, let's get on with the photo sharing opportunity. Continued. sam
Here's the ExpressLander fired up. One thing I didn't mention in the previous post was this stove has a difficult time simmering. The flame turns yellow with Kerosene at a very low setting. Otherwise, it provided some good heat for such a small contender. |imgRemoved|'thumb'
Hey Sam, quick question, how close it the priming pan to the connector as it looks to me like the hose is too close that on a windy situation it would lick the braided line and degrade the rubber hose underneath. What is your take on that? I have not really read reviews on this particular stove so do give your opinion. Ron
Interesting stove, in that they gave managed to make it small and not compromise the multi-fuel capability. Is it just a racket or a actual necessity to use only a Primus fuel bottle? I don't like that idea if it means the Primus fuel bottles are more expensive. If you had other fuel bottles you naturally would like to carry on using them. I wonder what the price would be in the UK? Probably 25-30% more expensive, though I hope I am wrong. I have seen this with Optimus pricing when looking at their stoves.
The distance between priming pan and fuel line is quite adequate. Picture angles don't show this. It's about an inch and a half away, so plenty of room. I used an MSR 20oz fuel bottle. I tried an 11oz fuel bottle could not attach the pump because the diameter of the bottle was too small. The pump's threads are designed at an angle to aim the fuel tube pickup to the side wall of the fuel bottle. I have a few large diameter fuel bottles from Brunton that are too large and would not be able to pick up fuel once the level became too low, so about the only size that can be used where the fuel pickup tube makes contact with the sides of the fuel bottle is the 20oz size. I did not try a Primus fuel bottle since this stove did not come with one. sam
Wow, 12 minutes on CF to boil? Not real good. I'd think if I was using this stove on a 'real' backpack trip I'd like better performance. Besides, wouldn't you go through more fuel that way? That's just me but seems like fairly poor performance, no? 8)
For a stove as small as this one, without using a windscreen in the (cold) outdoors I think boiling 1liter of cold water (mind, this is 5 cuppas!) in 12 mins is not bad at all. OK, it won't win any races, but still... Best regards, Wim
Right-o Wim, still...rather anemic stats for a stove that's supposed to serve as...well, a stove. I'd think there'd be better choices on the marked. Nice looking stove though, I guess. JMTC. There you go... 8)
That was 18 minutes on CF. The 12 minute mark was met by kerosene. Both burn times were not ideal conditions. I didn't use a windscreen and it was 18F ambient temperature, which is quite cold. Not only that but the kettle was one that I had kept outside with the water in it! The water had not frozen so I took a quick measurement and found it at 43F. Cold, but not too cold. I really believe that the CF output is due to the jet size of the stove. There wasn't another larger jet so to be universal on fuel the 28 jet is provided. Kerosene works best. I think I would rather carry my Svea 123 than this stove. It's just not powerful enough for my needs and wants. sam
Keep in mind that the windscreen also is a heat reflector. A lot of the "newer" stoves have the aluminum alloy reflector disc and windscreen included. You lose a LOT of heat if you don't use them. Especially at 18degrees. Kinda like turning on the furnace with the windows and doors open wondering why the house isn't warming up. LOL It is what it is. A neat, tiny stove. Mike
To me fast boil times are a waste of fuel, and I am wondering if the Primus ExpressLander has been tuned to do the most efficient boil times. My testing with using a standard 150 mm (6") pot has shown that if you boil 1 liter water faster than 12 minutes it is a waste of fuel, below is a graph of time vs fuel usage for a Trangia 27-1, a MSR Whisperlite and MSR Pocket Rocket. Note that on the graph at around 12 minutes to boil one liter, the PR hits optimum speed vs fuel usage, the PR also does not loose efficiency with very slow boil times, also note the Trangia at its fastest takes around 12 minutes to boil one liter and does not loose efficiency when the simmer ring is used to slow the boil times down. The same with the Whisperlite, it gained efficiency as the boil times increased and after 12 minutes there where very little gain in efficiency. For interest this is a low profile stove I designed and built in 2007. Tony
Those are interesting numbers. I'll have to remember to not be in a hurry to boil up something. I suppose with windscreen and less than maximum output combination, one could get a little better boil time and not waste fuel. Interesting for those that go on a little longer trip and can't be carrying too much fuel. edit: by the way, your stove looks really cool and quite similar to the ExressLander. Did you sell you idea to MSR? sam
Hi Sam, These test where done without a windscreen but in a windless environment, but I am not sure with no wind a windscreen makes much difference if any at all, Some time ago I did Some windscreen tests measuring the temperature of the gasses rising up the side of a pot with and without a windscreen and if anything in some cases a windscreen could help drag heat away from a pot when the water is at lower temperatures. As for me selling my ideas to any stove manufactures, in my dreams, besides designing, making and publishing on BPL the low profile stove concept sometime before Primus released theirs, I also modified a JetBoil to add a pre-heat tube long before JetBoil brought out the Helios. When the JetBoil Sol Ti comes out in Australia I have plans to make some mods to it. But to me it all just fun. Tony
Hi Tony, I guess I wasn't clear about the windscreen idea. Not really to block the wind, but more to trap the heat generated by the stove. I've gotten better boil times with these types of stoves. You can't trap all the heat, but you can use as much of the heat as possible so that it is applied to the pot instead of open air. Ground heat reflectors work too. This is all quite fun. You are an innovative fellow. sam
Hi Sam, I did understand that is what you meant, trapping heat by using a windscreen but I have some doubts that this really happens, if you look at the windscreen article on by blog http://tonysbushwalking.wordpress.com/2010/08/22/some-stove-windscreen-test-results/ you will see that the temperature of the gasses going up the sides of the pot between the windscreen and pot, rises as the temperature of the water rises, to me this suggests that the pot is loosing some heat to the gasses rising up the side of the pot. But then if you have the stove flat out then you are putting so much heat up the side then maybe the water might gain some heat from the sides. I have not tried testing the effect ground heat reflectors. Just my thoughts. Tony
Brilliant looking stove Tony! I tend not to use wind shields, but some stoves really need them. The best example I can think of is the MSR dragonfly, It has a large distance between the burner and the pot. It benefits greatly from wind / breeze protection.
If there is any wind at all, I use a windscreen. I learned that years ago when I couldn't get my coffee pot to perk after almost 40 minutes on my 502 when it usually was done in 20. I don't have any empirical data yet, but depending on the stove/pot combination it isn't so much the temp of the gas going up the sides as the reflected radiant heat in a windless environment. For those currents to be effective, I would think that the space between the side of the pot and the windscreen would have to be dangerously tight, otherwise, the vast majority of the heat simply escapes too fast to be absorbed. To illustrate, hold a propane torch at a steep and a shallow angle to a piece of thin steel. You'll notice that when the torch is held at an shallow angle, the steel doesn't get nearly as hot when it is held more perpendicular to the surface when it glows much hotter. The flame is the same temperature, yet the results are obvious. In household gas fired water heaters, the vent tube that runs vertically through the center of the tank has a wavy metal insert that slows the exhaust gasses down so that more heat is absorbed into the walls of the tube and hence the water on the other side. Radiant heat isn't affected by turbulance and other things that affect convection currents of hot gas. It is affected by the reflectivity of the windscreen and ground reflector as well as the pots texture and color and the angle at which it is reflected. It stands to reason that the dark, hard anodized pots with their flat finishes absorb radiant heat better than a shiny aluminum or stainless pots. In a perfect world, I suppose, we would have a perfect parabolic reflector polished to a mirror finish for windscreens and ground refelectors, but we, at least I, don't live there. The 64 dollar question is, "How much difference does it make?" I see more testing on the horizon. Mike
Hey Mike, You make some valid points. I would like to add also that it's not just a matter of trying to heat the side of the pot with windscreen but also of trying to keep the heat under the pot for a little longer. With the fuel bottle sitting quite far away, you can wrap a little closer. I think it is quite important to try as much as possible to keep the whole kettle/pot warm since any contact with outside air, especially in cold climates adds to or subtracts from efficiency. At a minimum, striving to keep heat under the pot/kettle is what should be done. My second best example of keeping the heat under the kettle is a Sigg Tourist and a Svea 123. The heat doesn't escape up the sides but is trapped by the windscreen/cook set and has to come back down to escape, by then you've used most of the heat. The best example that I can think of is the Nansen cooker. It has a 92% (?) efficiency rate at using the heat that is produced by the stove (according to Ernest Shakleton), so a windscreen or heat trapper can make a huge difference. See this link for Nansen Cooker efficiency: https://classiccampstoves.com/threads/17410 See this link showing trapping heat with a regular large pot over a smaller one. 32% reduction in time to boil: https://classiccampstoves.com/threads/13686 sam
Oh, absolutely Sam. I agree almost 100 percent with all of your last post. That Nansen rig is a BEAST. But, I'm more than a bit skeptical about that 92 percent figure in that if your not melting ice your losing a lot of that heat and ice is required to pull the downdraft on the outer channel. Hence a big portion of that 92 percent went into that ice. Ultra high efficiencies aren't that difficult to produce. Doing it in a portable package that requires no external power is another thing altogether. Downdraft systems inherently are very efficient but you need something to push or pull that downdraft. Whatever that is will take energy. No such thing as a free lunch. The Nansen Cooker is an amazing design. More impressive still is when it was designed. Talk about cutting edge. That was the space program of its day. I'm sure you could get really good numbers with a ported vacuum insulated pot but in order to get really good numbers with his rig you have to have extremes of hot and cold. (high delta T) Unfortunately that means you waste part of your efficiency, unless like Shakelton, you NEED all that melted ice to drink and cook with. And I'm not going polar any time soon. BI-polar, maybe. LOL! Take, for instance, a High efficiency gas furnace. These are really efficient because the hot gasses travel to progressively cooler portions of the surfaces of the heat exchanger. Ideally the exhaust is just over ambient temperature, but can never get all the way there. If it did that would be 100 percent efficiency and the laws of physics just went out the window. On the other side of the heat exchanger you have the forced air traveling in the opposite direction running over progressively hotter portions of it. Since our water in its pot is consolidated and relatively all the same temperature, we can't really get those kind of numbers. The best we can get would be close to the temp of the pot and the water in it. So as the pot gets hotter, we become less efficient since our delta T between the water and the stove gasses is getting smaller and the delta T between the water and ambient is getting larger. Which is why I don't boil unless I have to and 195F water makes the best coffee IMHO. Basically, if the exhaust feels warmer than ambient, you are losing quite a bit of energy. And our absolute coolest exhaust temp with any pot is 212F if we boil at sea level. Whew, my head hurts. Mike
