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Dan – R&D takes time. Excited to see where you are able to take this.
For sure R&D takes time and haste makes waste. Titanium sure is $, mistakes are costly.
I spot welded some vortex generators to the bottom of the ribs, now to do testing over the weekend.
Wondering if removing (several?) small sections of the ribs mid-run to allow movement of gasses between the compartments would facilitate a stonger vortex? And if it did, whether the complication was worth any improved performance?
I made 2 cuts and will test for sign of heat discoloration around the openings. Need to replenish my canister supply first.
This evening will do some water boiling and eat Mountain House for dinner.
Dan – if the snipped out sections “leak” and cause a problem, could a section be snipped perpendicular to the fin and rolled down similarly to a standing seam roof? The 2 cut ends could similarly be folded at 45 degrees to nearly completely seal everything back up.
After I made the cuts, I used a steel wheel brush to smooth over the cuts and for the most part, sealed the open area of the rib. Standing seam would work but probably a PITA to form. Thanks for the suggestions. I’ll do testing today.
I received the initial version (no vertex generators) from Dan (Thanks!).
My quick impressions from a couple of test boils…
This will be an excellent replacement for any regular canister stove. At 1.8oz for BRS stove + screen, it is lighter than my Soto Amicus and should function much better in the wind. The ergonomics of the system are very good.. it is easy to setup, takedown, and store. The handles stay cooler than without the HX Windscreen.
As a Jetboil replacement.. no. To get sub-3m boil times, I had to run the stove at a pretty high output. The HX Windscreen glowed red in spots and so did the stove arms. A lot of of heat was shunted to the fuel canister. Maybe a a bottom disc to shield the fuel canister would fix that, but I would still be concerned about fuel consumption.
The improvements are coming along nicely.
Because of the recent finding by Ryan and Hikin’ Jim concerning the failures of the BRS3000T, I ordered some Etekcity Ultralight stoves for testing. Want to see how well they perform within the full size windscreen heat exchanger. I like the 4 pot supporting legs better than the BSR’s 3 leg.
The added weight of the 4th leg is insignificant when we think in terms of safety.
Love to hear about how the stove goes. Also photos.
3 legs vs 4 legs: agree strongly. A 3-leg support is much less stable than a 4-leg support, for simple reasons of geometry. My latest stove designs go for 4 legs.
Cheers
Sorry for the delay. I have just the basic Windscreens ready without the possible improvements.
Kit come with a stuff sack, windscreen goes inside pot, lid on top of windscreen, stuff sack goes over the top of pot/windscreen and tightens around bottom of pot.
http://www.woodgaz-stove.com/titanium-windscreen-for-canister-stoves.php
http://www.woodgaz-stove.com/titanium-windscreen-for-canister-stoves.php
http://www.woodgaz-stove.com/titanium-windscreen-for-canister-stoves.php
Roger, Etekcity stoves have not arrived yet. I expect great results. You will be pleasantly surprised what I pair the stove up with. Yes, four legs better than 3.
This sale has ended due to lack of having one sale. I thought for sure someone would be interested in a full length skirt/windscreen for max heat retention. C’est la vie, c’est la guerre :)
I’m going to make a short version that will fit inside the pot. I’ll also add a ridge to the pot so the skirt will not accidently slide down while in the heat mode. Not sure when I can get to the new design.
My suggestions on windscreen that I think would appeal to more people
- Design the windscreen so it fits in the pot with a canister and a stove, even if that means only having fins on top or even losing the fins completely and counting on the rigidity of the titanium for the gap.
- Include a bottom heat reflector to protect the canister from getting hot and eliminate the key. See below.
- As this would primarily be a windscreen (less HX)… consider using a lighter gauge titanium. most folks may not use this every time so weight matters. Ideally, 0.5oz for the whole thing.
- I would target the Toaks 550 first because if it fits in that, it should fit in the Toaks 650/750 and maybe other pots designed to fit the 230g fuel canister.
- Have the option to buy just the windscreen + reflector.. I think most folks have a titanium pot already (or a dozen).
Squared circle.. large enough to cover the fuel knob but squared it so it would fit in the pot.
The bottom heat reflector is not needed in shoulder seasons if you are just bringing .75 L to the boil. A little radiated heat down onto the canister can even be useful – while monitoring the canister for temperature (Touch Test).
Cheers
Thank you for the suggestions.
I learned a lot, made some mistakes. Too much fiddle factor.
My interests are now focused on a 750ml pot with full length skirt for severe weather conditions. It will replace a Jetboil. We’ll see how that one goes over :-)
Large windshields: see photo below.
First of l, the aluminium windshield has been opened right out for the photo: it is normally a close 3/4 cover.
The height is significant: nearly to the top of the pot. This present a packing problem which I solved as follows. I slit the windshield full length in half, and joined the two strip together with high temperature (electroplating) masking tape. The tape is on the backside, and runs between the two pink lines. You can see the cut line between them. I fold the windshield in half and it fits inside the Ti cooking pot.
I had hopes that the tape would last a few trips before it had to be replaced. It has actually lasted quite a few years. One end is starting to tear and give away, as marked by the blue line.
At the bottom left hand corner you can just see a a yellow stripe: that is a micro-stake holding the windshield in place. The one on the right side was removed for the photo.
The canister is in front in this photo. It can be out the back, with the hose going under the windshield. This leaves a small gap at ground level, but that does not matter in practice. There is a 60 degree opening at the handle anyhow, so plenty of air is available.
Perhaps some of this may be of some help for ideas.
Cheers
Forming a hinge with metallic tape…clever! re: longevity of the hinge, sometimes surprising how long things can last when taken care of. And the failure at the ends is exactly what I would expect…perhaps a little reinforcement just at that point?
I agree mostly. I know I use a simple 4 layer aluminum screen that can be notched for the hose on one side and is about an inch open on the other. While it is certainly possible to use a tempered pie plate or serving dish as a source for the AL, it really needs to be annealed first, else it can crack from being bent. https://process.arts.ac.uk/content/annealing-softening-aluminium-plate/index.html
Special rivets, fins, vortex inducers, etc can be added in, the weight becomes a matter of questionable utility for trips less than three weeks. typically the weight of fuel saved with an HX pot and windscreen combo, is less than the weight of all the extras on a wind screen for 4 days.
You should always use your stove on low, ie, the heating is slow enough to allow conduction through the pot to overcome any cooling by the ambient air. In colder weather (down around 20F/-7C and lower) this might look more like a medium flame. In warm weather (around 50F/10C) it is much lower and looks like a low setting.
The biggest thing about JetBoils are the speed of heating. They also make use of an insulated sleeve around the pot. Yes, they save a bit of fuel, but speed is their primary concern, not fuel efficiency. Overall, I can match the JetBoils with a simple pot and windscreen for fuel consumption. It has gotten so I can guage the flame weight by sound using Roger’s V1, FMS-300t stove. A very light efficient little stove. It also lets me cut down on the windscreen height saving a bit of weight.
At around 1/8-1/4″ air vents (adjusted by eye) the closer wind screen can induce a vortex back at the pot, too. Actually, I assume several are created due to flow differences around the pot edge, functionally the same as a vortex inducer. The slight opening will let any additional exhaust gas to escape, but this is usually more of an air inlet, than an exhaust port.
As far as timing goes, yes, you can get a 1-1:30 min boil for a half liter. You can also spend close to 18-19 minutes. Longer burns on low are generally more efficient at heat transfer, but the ambient heat loss will catch up with you…between 7-10minutes seems the most efficient range. Interestingly, the lower times are better in COLD weather, not warm weather as you wold anticipate.There is greater heat losses in colder weather which mean turning up the flame to overcome this and the water will boil a bit more efficiently. But, we are only talking about two grams of extra fuel. An insulated wind screen is nice, but is more weight than it is worth. About the same for insulated pot lids, etc. But the savings are again, not worth it for all the fuel you will save in less than a couple weeks.
Simplicity, ease of use, overall weight, packing efficiency and efficient boiling are all needed in good backpacking windscreens. It is hard to beat a simple foil windscreen, used for efficient boiling and fuel savings.
What you see in my hand is the titanium body(750mlpot/windscreen/HXer) of a jetboiler. It has 72 linear inches(182cm) of HX fins touching the pot. It has high heat resisting flex handles that fold flat against the body for storage. Weighs 5oz/142gr.
Add a 7gr aluminum lid and 27gr BRS3000T(not shown) to complete the jetboiler.
Add all the helpful hints given in the comments to complete the package. Thank you everyone for the helpful suggestions and photos.
Just one more example as to why the Caldera Cones work so well – heat funneled up the sides as well as the bottom.
Dan, I like what you have done. Curious what the material is that you used to band it all together? Also like abandoning the “requirement” that the screen be removed and stored in the pot. Treated as a unit, this looks like it would be very durable.
Yes, the screen is permanently attached to the outside and is for the most part, non-crush due to the corrugations. No more storing inside the pot. Plenty room in pot for canister, stove etc.
The band is high heat resistant @*^%*!#@^. Had to do that because Stormin, Rand, Jon and others are watching ;)
And the failure at the ends is exactly what I would expect…perhaps a little reinforcement just at that point?
Old photo: tape reinforcement added when I got home.
Simplicity: what you need when you find a tent site in a storm and collapse inside :)Cheers
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