Last night I got curious of how long time a full tank of fuel my Optimus 8 and Radius 46 got them burning. I filled them up with Industrial Gasoline and lit them at the same time. I did not measure the amount of fuel but the catalogs says that the Optimus 8 takes 0.17 litre and the Radius 46 0.20 litre. My Optimus 8 was running 1 hour and the Radius 46 was running 2 hours and 10 minutes. My Optimus 8 was running little shorter than the 1 hour and 15 minutes that the Optimus catalog states but my Radius 46 runs way over the 45 minutes that Radius states in their catalog. Both were running with a nice blue flame. I did not make any boil time measurement so I do not know of the efficiency of them but the Radius seems to be the most fuel and cost efficient one. At least of the ones I own. Michael
I have just made a boil test of the two stoves and the Radius 46 boiled 1 litre of water in about 12 minutes and the Optimus 8 made the same in about 14 minutes. That is slower than the usual 7 - 8 minutes but these stoves are equal in time so I do not know if it is the fuel or the kettle that make them take longer time. It might be the fuel because I measured my JOBO 5000 alcohol stove and it made 1 litre of water in 8 minutes with the same kettle. Michael
Hi Michael thanks for sharing, That is quite noteworthy and maybe a test worth repeating. Two stoves with very small difference in design you've found very big difference in performance. Radius No.46 2 hours 10 mins run time AND quicker boil, wow. The test might be redone w/carefully measured amounts w/ same wind and air/water temps and get similar results. IF SO that would be noteworthy. We can "possibly" explain an (efficient) longer run time -OR- explain a (hotter) faster boil. HOWEVER, to get BOTH results from same burner seems inexplicable (how could it be I wonder). With a brief search I found other members w/comment "like you expected", they're finding the 2 are very similar. Your results are quite interesting, thank you again for sharing. You're thinking Radius may be that much better but I'm thinking there should be little difference and I'm missing something here. thx again OMC
I am of the opinion that such comparisons are very useful for you, the owner of the particular stoves, but probably less meaningful for others with similar stoves. Just too many variables and individual variation. Moreover, the most efficient stove under a set of favorable conditions can be the least efficient under another. I'd argue that any test in the kitchen or garage (as usually posted on youtube) can make a low-powered stove, such as an 8R, look like a decent performer. As much as I like my 8R, I know for a fact that it struggles to heat water when it is cold, wet and even slightly breezy. A wind screen only does so much. Under those conditions a real gas-guzzling blaster becomes relatively more efficient (and a time saver).
Hey, Itchy, You smacked it out of the ball park with your comments, my friend!! You're absolutely right, and that has been proved over and over again, and is still being proved today. Well said, and 100% correct, Itchy!! Take care, and God Bless! Every Good Wish, Doc
As I said in my first post, I was curious how MY stoves performed, so I tested them with each other. I shared this on this forum if someone was interested to see how two almost equal stoves had so different running times. There was in no way any thought from my side to show that other stoves in your possession should perform in the same way under other circumstances. If you had any interest of this information you use it or not. You do not need to tell me that the information is of no use but only for me. These comments only do that I do not want to share in the future. Michael
Michael, My hope is you remain positive and encouraged. You thought some of us might be interested with what you experienced and you were right. Actually the brief search I mentioned ALSO finds members interested in how the two compare. I've bid on some No.8s, I don't own either model (w/all due respect itchy), I think it's very useful info for stovies and not for just a stove's owner. I see your post as a *win win. Itchy mentioned variables and myself as well "The test might be redone w/carefully measured amounts w/ same wind and air/water temps and get similar results" (a measured approach). More on that and the *win win: maybe the result of repeated test(s) is NOT as big a difference after all. The win is it's good to know they're comparable. -OR- maybe your 46 IS especially efficient AND hot. That win is it will be good to know, IF one might figure out, the "HOW" is the performance improved. edit Itchy, I encourage his post I'm not saying you don't. I agree w/your comment aside from I think it is useful for us to share performance experiences side of a house or side of a mountain, where ever. thx again OMC the flat lander
Please do not be discouraged Michael. I too, do boil tests to see if I can improve stove performance. The really hot stoves boil 1 litre in 4 - 5 minutes (fully pumped Coleman 400 brown, Coleman 505A and Primus Omnifuel). Smaller stoves (Optimus 80, Primus 71 and Sievert SVEA 123 take 7 - 8 minutes). Self- pressurising stoves always do better with a 5 minute warm up on full setting. Cheers Simon Foxxx New Zealand
G,,day . not to upset or disagree , just a different aspect . if we are interested in the time to boil water . shouldn't the time be taken from unpacking / opening the stove . if not that , surely from the time of lighting , or preheat . if we take 5 minutes for a stove to warm up . but another one can burn at maximum heat at light up . I think the comparisons are comparing apples to lemons , or a watermelon ???? ok . I think I have sown a seed of thought here . who was it said ; I am getting my coat , bye people . cheers, kerry
Good Morning, Michael, Please do not be upset or bothered by some of our comments. Like others, I found your post to be interesting, and enjoyed reading about your testing. However, these days, when someone posts something like you did, new Stovies might look at it and say, "Hey, how come my own stoves like that don't perform that way"!! Testing it outstanding, but unless it's done with extreme precision, it's not of much value to someone who needs to know about a certain model of stove, overall. Very few of us have the time, or resources, to put together a comprehensive set of tests, which would also include temperature, wind speed, humidity, elevation, and a host of other variables. So, again, don't be upset about our comments to you. Please keep doing exactly what you are doing, and share Stove Fun here, just like you did. I look forward to reading more of your Stove Adventures!!! Oh, one last comment: My wife and I live in the mountains of Southern California, at 5,000 ft of elevation. I can test a stove up here, then drive 20 minutes down the mountain, and test it again, and guess what? Different results!! If I were to drive to San Diego, and test it at sea level, I would get different results again. See how easy it is to be confused about all this, if you are a new person, just looking for information? We all learn that lesson, and that's part of what draws us together as a happy Stove Family!! I am glad you are a part of it, Sir, and keep up the good work! Take care, and God Bless! Every Good Wish, Doc
Michael, sorry if my comment sounded like a personal attack of some sort. It was not meant to be. My reply did drift a bit from your specific subject; I tend to do that. Moreover, I do not have a Radius 46 (you lucky dog you) so I cannot do the comparison. If you have found a stove that can both produce more heat and run longer on a given amount of fuel, it is certainly worth sharing that finding. Oh, and OMC often does not agree with what I write -- but I survive, and smile.
Thanks for sharing the results. I've been eying an 8R or 99 on Evilbay for a while and it's good to get some more data on what the upper and lower range these stoves can be capable of. If I may ask what was the air temperature and elevation of where you tested? Indoor or outdoor?
Michael, very interesting stuff about boil times. I too have done boil tests on my self-pressurizing French Vesta stove. I did this to familiarize myself with the stove's idiosyncrasies and get an idea of its capabilities. I hadn't posted about this because (as itchy points out) there are just to many variables for the results to be useful to others. The one thing I can say is that Simon Foxxx is right about self-pressuring stoves performing better after they run for a bit. Immediately after preheating it takes 12 min. to boil a quart of water. Once the stove really gets going it can bring a gallon of water to a rolling boil in 16 min. The fuel tank on this stove gets scary hot after awhile and pushes fuel out the burner at a furious rate. While others can't glean much from my tests on a single stove, I believe more can be gleaned from your comparison of two stoves. While others will surely get different boil times depending on the circumstances of their testing, the relative performance between the two stoves should generally hold true. This would be valuable information to someone interested in acquiring one or the other.
Thank you all for your kind replies. My “test” was in no way a scientific test. I only wanted to see how these two stoves was running side by side because they are, at least in my opinion, competitors to each other. When I then got so different running times I wanted to share that. The “test” was indoors in my home which is at sea level +10. I have about 500 meters to the bay. The temperature was circa 20 degrees C and the fuel was the same in booth. I am completely aware of that the result will probably differ when the environment changes. Cold weather, the wind, high altitude, high moisture, different fuel and so on will make a different result. In any case, the environment was the same for booth stove when I compared them. Michael
Even two of the same stoves can differ greatly. I've a pair of Coleman 502's here, one runs like it's pushing a Tomahawk missile going balls out, the other one is just a so-so example. I'm not real impressed with self-pressurizing stoves, I've a 8R and a Radius 42, had a 99 in the past, they work, but the performance could be spotty, Simon Foxx hit a big part of it, getting a good run-up is crucial, I've also had some fuels that worked better than others in these stoves, n-heptane is the top cat to make those stoves purr! Murph
Murph, thanks for the heptane idea. The n-heptane you recommend can be purchased for around $100/liter from chemical supply companies. Regular heptane, a mixture of n-heptane and its isomers, can be purchased for $25/liter on Amazon. When used as fuel, I doubt there's a dime's worth of difference between the two. I think I'll buy a liter of the later and see how it compares to Coleman.
