With a remote-canister stove, should the windscreen have any ventilation holes or slots cut in at the bottom? Or should there just be the notch for the gas line to get in & that's all?

Edited by trtlrock on 10/03/2009 10:08:07 MDT.

Hi John,
Usually windscreens for any alcohol stove have ventilation holes at the bottom. Otherwise, you would choke the stove.

So for an IsoPro MSR WindPro setup, best performance would be achieved by keeping the gas-line notch at the bottom small, and no further holes? I take it that further ventilation holes would decrease fuel efficiency somewhat and/or result in slightly longer cooking times?

Edited by trtlrock on 10/03/2009 10:10:35 MDT.

Hi John,
Sorry, I missed "canister" and thought you were talking about an alcohol stove. I was thinking you were making something like one of Tinny's remote fuel alcohol stoves.

Do you have a picture of your windscreen? That would help answer the question better.

-- don't have a pic easy to post, but it shouldn't be necessary.

I'm using the one that came with the MSR WIndPro. It was unnecessarily tall, so I trimmed it down in that direction.

It came with a huge freakin' hole for the gas line to enter through. That hole got a lot smaller when I trimmed the screen so it made a tighter circle. However, thinking the huge whole must be a design feature allowing for air to enter 'from below' I roughly replaced the square inches lost when tightening the circle by cutting notches out of the bottom of the windscreen.

I thought I saw a recent pic of Roger C's windscreen and it looked as if there were no holes at all...hmmm...

Hi John,
I think you're right about using that big hole for air flow. Have to tried it without holes? I kind of think you should have at least a few at the bottom but I haven't used this set up before.

Thanks Jason.

Roger? You out there?

Sooo...

With a REMOTE-canister stove (MSR WindPro), should there be any ventilation holes or slots in the windscreen other than where the gas line enters?

edit -- 3-season, no-snow conditions

I know it's a noob question, but I've looked at all the links below & can't seem to find the answer, as none of the articles seem to address REMOTE-canister stoves:

http://www.backpackinglight.com/cgi-bin/backpackinglight/wind_dynamics_and_windscreen_design_part_1.html

http://www.backpackinglight.com/cgi-bin/backpackinglight/wind_dynamics_and_windscreen_design_part_2.html

http://www.backpackinglight.com/cgi-bin/backpackinglight/canister_stove_faq.html

Edited by trtlrock on 10/07/2009 10:30:35 MDT.

If you are using the screen that comes with the WindPro, then there is usually enough of a gap around the pot to supply adequate airflow. If, like me, you use a Caldera Cone that perfectly fits the pot, then I imagine the holes at the bottom become more important.

Hi John

With ANY stove, no matter what fuel, you will need an air supply for combustion. I think that is pretty obvious.

The air *could* get to the fuel/flame by coming down between the pot and the windshield, but that is pretty unreliable and cools the pot. Far better is for the air to come in from underneath, so the hot gases rise up beside & around the pot.

Inadequate air could lead to CO emission as well, although you would have to be pushing for that to happen. But why take the risk?

I have windshields with holes at the bottom, but my experience has been that the holes weaken the aluminium a bit. Since my windshields get rolled up and unrolled an awful lot, I prefer plain foil without weaknesses. But, ymmv.

I usually wrap the windshield a bit more than 3/4 of the way around the pot. I do not try to close the gap fully.

This would be pretty typical. There is a significant gap on the downwind side which allows me to get to the control valve easily. More than this is certainly not needed.

I don't close it up any more than this for two main reasons. The first is that I usually cook inside my tent where there is some shelter to start with. The gap does not cause me any problems with wind. The second is that closing the gap any more is not really worth the effort - I'm lazy!
.

Even under extreme conditions (and this *was* a bit extreme!), I would still have about that much gap. You can't see it here because the gap is pointed downwind, but it is there.

Would a small notch be adequate? I would prefer something a little larger than that, just to make sure the air flow is adequate.

Cheers

That is EXACTLY the kind of detailed response I was looking for. And pics too!

This should be grafted onto some sort of stove FAQ...