Alcohol Stove Efficiency

[frediver]

Truthfully I'm not sure I would pack an Alcohol stove for more than a short hike.
I really like my Turbo 11D but with my style of cooking fuel for over 1 week adds
up fast. Over the long haul I expect you will avg. at least 1.5 oz. fuel use per day,
I use closer to 2 oz. Hot drinks in the am/pm, hot cereal in the am then dinner water.
So one week =12-14oz. fuel =24cups=6qts.
Now if I use the same style of wind screen ( roof- flashing ) the total weight might increase 1-1.5 oz over what would be needed for my brasslite alone. A good cartridge stove can weigh as little as 3-4oz. and a full 1 lb. tank of fuel about 24oz. ( stove,fuel,
wind screen) total pk about 30-32 oz. using a 1/2 size fuel tank might weigh 16oz total.
The small tank will boil about 6-7 liters of water using 100gm of fuel. An Alcohol stove
will require twice as much fuel. (100gms= 3.5 oz ) so 1 8z. cart. will boil 12-14 liters.
Have you checked the REI web site?
After all that I still like my Brasslite I just dont know if I would depend on it as my only source for more than 5 days, packing 7 days worth of fuel.
I was hoping your thread would convince me otherwise.

[Hetchy]

Hey Thanks for the info. I am going to look at the REI site again.
I think I was rather hoping to find a solid answer, but like so many things in life it seems to come down to personal preference I guess. I must admit I really like the silent burning of the alcohol stoves but that is likewise totally illogical if I am trying to lower my packweight not to look the CERTAIN weight advantages of the canister stoves.
I did manage to build a pretty decent Alcohol burning stove out of two Heinekin cans and a strip of coors can. I used the Penny design but left out the penny and the quarter inch hole. Instead I made a 1/32 hole half way up the dish. I also made 8 burner holes 1/32 around the ring. I put a divider strip in between the halves. When I fill the dish the alcohol stays up top, not able to drain into the bottom through the 1/32 hole. As the stove primes and heat a vacuum is created in the center chamber and draws the fuel in, forcing vapors out of the 8 jets in the burner ring. The remaining fuel below the hole in the primer pan continue to burn as the 8 jets of the ring come to life. When at full power I have 8 small jets around the outside and one large jet of flame in the middle. 9 Jets of FIRE!
I shall call it my "Little Heiny 9" !
I will be famous and sell millions of them...MuaHaHa!
Okay, reality check.
The best fuel economy I can get with it is 1 ounce per 2 cups(6minutes) including priming and it dies just as the water reaches boil. And that is back here under smiling conditions at 1532' elev. I think your figure of 2 ounces/day is more realistic. Despite the fact that my homemade Alky weighs a fraction of an ounce, the fuel weight more than makes up it's weight advantage over my Trangia. In fact the Trangia under the same test uses 3/4 ounce of fuel.. but is 3 ounces heavier!
Interestingly, I also found that the cure for an Alky stove that burns too quickly, perhaps wasting heat, is to add a few drops of water BEFORE starting the stove. My little HeinY stove I made burns it's ounce in 6 minutes.Originally, I noticed the flames would creep out from under the pot and actually rise above the level of the lid. I believed this was wasted heat so I added the water (Trangia manual suggested it) to slow the reaction. The stove did seem to burn a bit slower(subjective) though I really have no way to accurately discern the exact difference with the equiptment I have. I was able to get my stove to keep most of it's flames under the sides of the pot.. thus the 1ounce/6minute/2cups performance. Although when it gets ready to die it always goes out with a little burst for the last 10 seconds or so! Really cool looking in the dark!
While I am not giving up on the Alky stove I plan to now take on the PCT, I would be remiss If I did not take another look at the canister stoves.
Thanks for your help everybody! Hey if nothing else I got to drink beer for the first time in a while.. FOR SCIENCE!!!

[freestone]

I am a Trangia affectionado, actually more like a junkie. I own all three models. I also own a Svea 124R, Sierra Zip, and a canister stove (uh oh, stove junkie!). My former hiking partner had a Whisperlite so I used that a lot also. I started to make a cat stove but I felt like I was trying to reinvent the wheel that would never be as good as the Trangia burner, the simmer ring and O ring cap are two big reasons. Two factors control the efficiency of alcohol stoves, breathability and distance of the pot to the flame. If the windscreen is too tight, then the stove will not burn poorly. The Mini Trangia is my choice for solo trips but is marginal in a strong wind so I set up a wind screen. The 27 Series is heavy but the windscreen is a work of engineering art and simplicity, stable, fun, and easy to use. It's efficiency actually improves with a wind. On all the Trangia sets, the burner to pot distance is perfectly set so that the pot sets at the hottest part of the flame. As soon as my water boils, I put the pot in a cozy, and throw on the simmer ring to extinguish the flame. On cold mornings, I can fill the stove with fuel and put it in my pocket to warm it up. It is however, proven science that the canister stove is the best for longer trips but I have issues with canister disposal, so I go for the alcohol on my trips. Off topic, Hetchey, are you going to journel your PCT trip on Postholer or Trail Journels? It would be fun to follow you on the trail!

[Hetchy]

There you go Freestone! Now you've got me re-thinking again!
No actually it's a good thing, Thanks.
Last night after about the millionth experiment my home made Heinekin can stove failed me.
Like I said it was an experimental design.. obviously a bit too experimental! I should just follow directions and make the design like everyone else does, but that ain't my style.
So at the moment I am back to being a Trangia Boy.
I still can't get my brain around the whole fuel weight versus stove weight versus efficiency. I think I am going to just breakdown(and cry..NO!) and bring the Mini-28.
Haa! I though of a funny thing! When I began to plan this PCT hike I needed extra cash to update my gear. So I sold my Ruger Mini 30 rifle.. so I could buy among other things.. a Trangia Mini 28!
I think it's funny :retard:
My base weight is 10.5 lbs at the moment. The trangia only(ONLY!) adds 3 ounces. But like you pointed out the o-ring sealed cap and the ability to completely control the flame ie. simmering/snuffer, are not to be overlooked. And it gets 3/4 ounce fuel to 2 cups H2O boil economy. And it is made by fellow Swede's!
"Hey Swede's!...There Norweigians Mac." (The Thing.. Kurt Russel)

I am on Postholer.com
My journal is under: Matt Edwards
My Journal is called: Matt's Pacific Crest Journey

I am planning to update it from the trail towns(libraries,trail angels etc) though I do not think I will carry a cell phone for this purpose.
But who knows?
A smartphone or Blackberry could be in my future. But knowing they way I destroy electronics.. I dunno!

[freestone]

I wrote

If the windscreen is too tight, then the stove will not burn poorly.

but meant to say "the stove will burn poorly" :retard:

One time, in an effort to save grams, I tried putting the burner straight on the ground, then placing part of the windscreen from the 27 series over it. The results were disapointing. It took twice as long to boil water even though it appeared as if the burner was fired up to the max. My conclusion is that air flow is a calculated design function for any stove to operate efficiently, and twicking original designs is a waste of time.

Hey, I am a fellow Swede also (Axel Johnson!). Good luck on your thru hike. It's my goal to do it at least once before I start pushing up daisys.

[Hetchy]

My mom's side is Swedish. They are the Pearsons. My Dad is from Cornwall England. Tin mining country for ages. They say if there is a hole in the ground you'll find a Cornishman at the bottom of it! Indeed I became a plumber and I am(was!) constantly crawling around under houses repiping etc.
I will need to be Stubborn as a Swede and as Hard working as a Cornishman for this hike! Not that Swede's don't work hard or Cornishman aren't stubborn. Oh well.. You get my drift!
In my testing of both the homemade and Trangia stoves I found the base to be a factor in the quality of the burn. If I set the stoves flat on the cold countertop(Not Recommended!) they took longer to reach full steam than when I put them on an overturned pie pan. I think the counter top insulated the stove better than the pie tin but drew more heat out the bottom of the stove so less was left for vaporization. In the front yard at the ranch I have been propping up the Trangia base on twigs to keep the conduction losses down.
One of the best tricks, and I think I posted this elsewhere, is to preheat the fueled up but unlit stove body on the inside of the thigh before use. I sit Indian style so it is a simple action, if a little startling! No need for caffeine! The trangia takes off in no time when this preheating is accomplished. The homeade Alc preheats(on skin) quickly but has less heat capacity so I think that is why the effect is less apparent on it.