Topic

Extremely wind-resistant 4 fuel SUL cooking system

Viewing 13 posts - 26 through 38 (of 38 total)
PostedJan 9, 2022 at 5:11 pm

David, the stainless steel mesh covering the holes is a great idea, keeps embers safe within the windscreen.

David Gardner BPL Member
PostedJan 10, 2022 at 12:47 pm

Dan,

In addition to holding wood embers in, the ss mesh mitigates the effects of wind/chaotic air flow, similar the small holes below the burner in the Windburner system. The idea is that at low flow rates the flow is laminar and smooth through the screen, but when a gust hits and tries to push air through faster the flow becomes turbulent and can’t flow in as fast as the gust is trying to push it.

No separate wood stove is required. The pot is supported by the windscreen. Just pile wood and twigs inside the windscreen, leaving about an inch of space below the pot, and ignite. I’ll fire it up tonight and post pictures, but here is a photo of me (on the left) “naturally aspirating” an earlier set up at GGG 2017 “Burn Off” that basically functions the same way:

PostedJan 10, 2022 at 4:15 pm

I’d bet you came in 1st place at that “Burn Off”

This is you on the left naturally aspirating?

What is your goto fuel?

 

David Gardner BPL Member
PostedJan 10, 2022 at 4:27 pm

I did. I have a special competition set up made just for the Burn Offs. I improved it a couple of years ago, but the last two GGG’s have been canceled due to the pandemic so I haven’t had a chance to use it yet.

Yes, that is a photo of me (on the left) “naturally aspirating.”

Go to fuel? Whatever is available on site. At the GGG we use 12″ pieces of 2×2 douglas fir as standard “fuel units” for the Burn Off.

dirtbag BPL Member
PostedJan 10, 2022 at 5:34 pm

I love my pocket bellows!!! Always in my hip pack!!

PostedJan 11, 2022 at 9:03 am

Nice!

I don’t see the stainless steel mesh on intake holes, different windscreen?

How much water in the pot and how long to get a boil with one load of wood?

Can you show us how you stack your wood and tinder please?

How is the pot supported, I don’t see the supporting ring?

 

David Gardner BPL Member
PostedJan 14, 2022 at 11:32 am

I don’t see the stainless steel mesh on intake holes, different windscreen?

I’m still experimenting & testing different size ss meshes. This happens to be between two different meshes, when I have removed the first but not yet added the second.

How much water in the pot and how long to get a boil with one load of wood?

2 cups, 8 minutes for this particular pile of random wood scraps.

Can you show us how you stack your wood and tinder please?

The first photo shows that. For this burn I used the log cabin style stack, sometimes I use the teepee style, depending on the size and type of wood. Tinder is in the center of the pile, kindling on top of that, then wood pieces of increasing size.

How is the pot supported, I don’t see the supporting ring?

The rings are not support rings per se. They are there to reinforce the can and mark the 1 and/or 2 cup fill lines, although they also make strong anchor points for the windscreen. But the windscreen supports the can by itself, even without rings. I used a different can in this set up because it has a bail so I can lift the can and windscreen off the embers without getting a hand to close to the flames. It’s an option on all my cans.

David Gardner BPL Member
PostedMar 12, 2022 at 1:02 pm

Just in: After a few tweaks (more inlet holes), I have some great wind tunnel test results for this rig in BRS mode, starting with 500 ml of water at 68* F (20* C).

  • Baseline no wind: 5:08 min to boil using 5.8 g fuel
  • At a steady, measured 8 mph, with the bottom burner plate in place: Boil at 5:35 min avg. using 11.8 g avg. fuel
  • At a steady, measured 8 mph, without the bottom burner plate: Boil at 7:45  min using 13.2 g fuel

Thank you Jon!

Wind tunnel tests on the alcohol mode still to come.

Yet to be fully tested is a system using a secondary outer windscreen:

My own box fan tests of this set up burning alcohol in a measured 3.5 m/s (7.8 mph) wind averaged 15 min and 18g fuel to boil 500 ml of 32.1* – 35* F water.

You read that right: boiled 500 ml of ice water in 8 mph wind using 23 ml of alcohol.

Viewing 13 posts - 26 through 38 (of 38 total)
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