chemically, they're CH4 so you're quite correct. however, what's heating my house now, either from the north sea or russia is a finite fossil fuel. that from human or cow excrement is a renewable biofuel, so in terms of politics, climate change and sustainability quite different
Sparky, a fiver says many of the stoves that had roarer burners and no pump are white gas burners and use the prime cup to pressurize their fuel feed. They were also bottom-line stoves, no frills, no moving parts to break, bare bones units. And even some of those had a drop-in silent burner option to replace the flame spreader plate, which, IIRC, was part of the inspiration for Gary to make his series of BD silent caps! Murph
Murph, exactly...I was thinking about my 123 and 8R but I do have some kero burners that have a pre-heat cup and a tank pump. It just struck me odd that the roarer burners, which rely on the velocity of the fuel gas, often had no tank pump and the silents, which do not rely on velocity of fuel gas, have pressuring pumps.
Sparky, look at how many silent burners are set up for kerosene, the poor things need all the help pressure-wise that they can, even WITH a prime cup! Darn prime cup has all it can do to get the burner head up to vaporizing temp as it is, and some of them need to be primed twice! Murph
As a rule, a kero stove must have a pump, be it roarer or silent. It needs the pump to pressurize kerosene, which does not generate sufficient pressure from tank heating.(I saw one exception to this rule - a weird looking kero stove with a coiled copper tube burner, that had no pump.) That also goes for multi-fuel stoves - they must have a pump, not because of burner type, but to pressurize kerosene. The white-gas-only stoves have the option of no pump, and as Murph said, they may come with roarer or silent, in either pump flavor. Yonadav
Murph - Is this really so? On a recent test of mine I found no difference in fuel usage with a 96 …flame spreader vs Silent Midi – Cap: Primus 96 1930 vintage, boiling 500ml of water (water temp 12˚C). This was carried out three times: 4’.42”, 3’.02” & 3’.11” 23.15 grams of paraffin was consumed for the 1500 ml of water boiled (in 500ml increments) therefore average 7.72 grams paraffin/500ml water. This was repeated using one of Gary’s midi-caps: Primus 96 1930 vintage, boiling 500ml of water (water temp 12˚C). This was carried out three times: 3’.54”, 2’.34” & 3’.27” 22.76 grams of paraffin was consumed therefore average 7.59 grams paraffin/500ml of water. I use an accurate laboratory digital balance - resolution 0.01 gm which I use in my handloading. I like to use a silent cap/burner, not for any imagined or real economy but simply because in a tent or just sitting quietly in the countryside it is nice not to be deafened by a roarer burner! Maybe they have silent burners so not to be deafened in the kitchen!!!! I do love silent burners for the reasons I stated earlier above. Cheers, Rob
Hi Rob, Your results are in broad agreement with my rather less scientific tests. I was measuring boil times for 1 litre of water and found that that Gary's midi-cap was the fastest: https://classiccampstoves.com/posts/121281 In the thread I did express the opinion that this shorter boil time would be at the expense of higher specific fuel consumption. I reckon Primus "sorted-out" their burner designs very early on, and achieved high thermal efficiency with each of their designs..be they roarer, coil-burner, or silent. The choice of burner is therefore likely to be based on other attributes, such as reliability, appearance, noise output, or initial cost, rather than usable heat output per unit of fuel. Best Regards, Kerophile.
Hi, Kerophile, I think you and Snowgoose are right in your theories about all this. Even in my far less than scientific testing over the years, the results are, generally, the same as you Gents have found. Like you, I found that Dawg's outstanding caps do burn hotter and boil faster, but at the expense of a bit more fuel consumption. Personally, this is not a problem to me, and I LOVE using Gary's wonderful caps! I like silent stoves, roarer stoves, and some of the in-between stoves, too!!! Take care, and God Bless! Every Good Wish, Doc
I think that your observations are an astute summation and agree. Me too!!!!!!!!!!!!!! I think that they are really wonderful – form and function at their very best. Cheers, Rob
Am I missing something? The BD cap does not alter the jet, so how can it increase the fuel consumption? If it boils faster, it should save fuel, IMHO. I have one Minicap, and I love it. It is definitely my favorite. Yonadav
Hi, Yonadav, Don't know why, but that seems to be the case in the stoves I've tested with Dawg's wonderful caps. It's most apparent with my Omnifuel, but seems to work the same with 8R, 123, and Radius with which I've tested it. One thing to consider is this: Any stove will use more fuel if more pressure is taking place. For example, if you use a SVEA 123 and let it self-pressurize, it will burn a certain way, and use a certain amount of fuel. IF, however, you add in the Optimus Mini pump, and fuel cap, and crank up the pressure a bit, then the stove WILL burn more fuel as it boils faster. Don't know if Gary's caps work that way, or not, as they are not really adding more pressure. But, in any case, that's my take on it. I should do more controlled testing, but so far have just noticed that the fuel goes down faster with the caps, than with their roarer flame spreaders. Again, this does not bother me in the least, as Gary's caps are flat-out amazing, and I will continue to use them, even if I do burn a bit more fuel!! I can't say enough good things about them, truthfully, and I believe that anyone else who has one, or two, or more of Gary's outstanding caps, will love them just as much as do I!! Take care, and God Bless! Every Good Wish, Doc
i've mainly used Gary's caps on the 96 in roarer mode you can only pump a few pumps before the flame tips turn yellow but put a bd cap on and the same stove can take a lot more pressure and not turn yellow so you run the stove at a lot higher pressure ergo faster boil times as for silents being better at simmering dunno as i'd agree on that a roarer simmers and can be pumped up again straight away as the flame is always heating the head silents tend to flare if simmered for a long time then pumped up again i found
I agree with Yonadav, and what Bill says makes a lot of sense. Maybe the boil time tests should be made by starting with the same amount of fuel, same ambient air temperature and pressure, and then using the same number of pumps. To further refine I'd suggest measuring out the same amount of priming fuel (meths or whatever you use), and priming and lighting (again with the same number of pumps) with the pot in place and measuring the time to boil from the point at which the priming fuel is lit. This would give another indication of relative efficiencies of each burner set-up by including the time they get up to maximum steady state efficiency by taking into account the differential in burner mass between the systems. By using each these approaches you'd get an indication of the relative efficiencies in terms of start-up, and also steady state. Of course, at the end of the day it doesn't really matter. You either want a nice roar, or a gentle hiss. Whether one takes 30 seconds longer to boil than the other is neither here nor there. And if someone suggests that 30 seconds might be the difference between life and death then I'd strongly suggest that they include a small mirror in their pack. They can then use their last 30 seconds to look into the mirror to apportion blame for the situation rather than looking at their stove Edit: I guess one reason for more fuel consumption could be that if the silent caps are running hotter there is more heat conducted and/or radiated back into the tank thereby creating greater pressure, thereby consuming more fuel. Whether this is a controlled or uncontrolled feedback mechanism is open to conjecture and some thought would have to be put into whether burners will continue to burn at the same efficiency irrespective of fuel presented. Alternatively, is there a top limit to the amount of fuel that can be released from the jet under ever increasing pressure such that the tank over-pressurises? Probably more of a theoretical consideration than a practical one. In normal use it's usually a quick boil and finish, or a quick boil and a simmer. For snow melting utilising a longer full blast burn I'd suspect the ambient low temperature would act as a suitable excess heat sink. The only issue might be melting quatities of snow inside a cabin. But stoves should never be left unattended anyway so again, probably not an issue. Cheers, Graham.
Hi Yonadav, What you are "missing" is the understanding that the power that can be achieved by a burner is not only determined by the diameter of the jet aperture. A one-pint stove producing a maximum of 1.8kW and my British Army No.12 throwing out almost 3kw both use 0.32mm diameter apeture jets. Both are working efficiently with lovely blue flame patterns. However, the size and surface area of the 1-pint burner body is much less than my No.12 burner, so the volume of vaporised kerosene available to exit the jet is much less, and this limits its ultimate power. Similarly, a stove burner can work efficiently over a range of powers, depending on tank pressure, or the setting of a regulating valve. The jet aperture has not changed, only the volume of fuel vapour available to travel through it. I believe that in the case of Gary's caps, the heat transfer to the burner is increased and this increases specific fuel flow and heat output. You get your meal quicker but at no nett saving of fuel. Best Regards, Kerophile.
Hi, I won’t bore you with all the figures but I can find no difference in fuel consumption between a roarer and a silent burner with one exception. I have used a 00 with a I pint roarer, an 00 with a 1 pint silent and a 00 with a 2 pint silent burner and the difference in fuel consumption was within 0.5 of a gram which is nothing. The best fuel consumption in my tests so far is an 00 fitted with a 45 rising tube and a 2 pint silent – I got fuel consumption of 5.93 grams paraffin /500ml water boiled against 7gms (± 0.5 grams or so) for the others. I always do everything in triplicate at least some times six times. Priming with meths (the amount) is standardised. Everyone else will get different results – my tests are always carried outside, I record wind speed, ambient temp and water temp. None of this matters one jot of course – I carry out tests just for my personal interest. In the outdoors I love the silence of silent burners, regardless of whether they are proprietary burners or Gary’s mini, midi, omni etc. Of course there are times, particularly when it is blowing a hoolie then a roarer is the only way to go – that is why I carry both. Cheers, Rob
Greetings, Kerophile, and All, I had forgotten about the tanks getting hotter, and thereby increasing pressure!! Of course, this is what makes for more fuel useage with Gary's caps, exactly as it does when you use a mini-pump, or regular pump, to increase pressure!! Duh!! "Comes the dawn....."! Back when we first tried some BD Mini-caps, at CASG2, all of us noticed that each stove tested, ran a good deal hotter, than it ran with it's regular roarer flame spreader in place. I mentioned this to Gary after our tests, and I believe he had found the same thing in his own testing. However, the increase in heat seems to not cause any safety problems, and I'm thinking it is exactly what would happen if you pumped up the pressure in the tank, using a standard pump. In both cases, the fuel tanks get hotter, pressure inside the tank is increased, boiling times are faster, and you use more fuel! I think George hit the nail square on the noggin with his thoughts on this! One really fine plus from all this, is that you also get a fantastic simmering capability from stoves that, whilst they simmer OK, cannot do it as well as they do with the addition of one of Dawg's great caps!! To me, the picture is complete, and now makes total sense. And, like Snowgoose, I will make sure that all stoves that can use one of Gary's fine caps, also carry along their original flame spreaders, just in case I feel the need to swap them back to original specs. Ahhhh.... it's nice to have such outstanding choices, eh?!! 8) Take care, and God Bless! Every Good Wish, Doc
It's a bit difficult to determine which one is more efficient. But in my experience silent caps show better (read:complete) combustion behavior. I always get clean blue flames with a silent cap whereas roarers show yellow tips quite often. In real life absolute power is quite unimportant. Running a stove at max output is the best way to waste fuel. Provided you have a good windshield (read:Trangia) which you will need with both types of heads, you'll be most efficient if you run a stove at an output rate where the flame tips stay below your pot, never extend around it's sides. This is most important in winter where you need up to 3 times the amount of fuel when melting snow. At least that's how I run my stoves, enjoying the silence of a quiet head. juergen
I once read that a 123 provided a wonderful soundtrack to backpacking. I'm not yet to the official social security age, but am getting there. My very arliest memory is of mom perking an aromatic morning pot of coffee over a roaring Coleman while the family was camped down by a babbling river. My first time living out of doors! The smells and sound of that instant were wonderful enough that it lasted forever!
Darto501 it is often such great memories which bring most of us here back to camping and stoves. The total enjoyment of a fresh brewup be it coffee, tea, or some other hot drink alongside a stream,lake, or just in the backyard garden. And for some who are not "outdoorsmen/women" it is the aroma, sounds, or pleasure of the moment to have a brewup in the kitchen, garage or basement shop. WElcome to the ship of pyros who love the experience of making water hot and the savory flavours of a morning, noon or just because drink. No 'enry i have not been into the spirits again. lance
