The Ocelot Windscreen for Canister Topped Stoves

[Jon Fong / Flat Cat Gear]

Dan is exactly right, if you run the stove full there can be a problem.  This is where I need to clean up the messaging and target the product correctly.  As with many Backpackinglight members, a common goal is to be light weight and fuel efficient.  Not everyone out there is.

A customer was experimenting with the Ocelot system and cranked his stove up to 50% power.  He achieved a roiling boil in just over 3 minutes.  HE was interested in time efficiency and not concerned about fuel consumption.  He then went to 100% power, not good.  Similar to a car with a stick shift.  You can drive 65 on the freeway in 1st gear, but it is not a good idea to do so.  As with a lot of the world, common sense isn’t.

Part of the re-write will be education and clearly stating the objective of the product: fuel efficiency.  The current design does cut fuel consumption by ½ to 1/3.  That is the value proposition and it has to be pitched that way.  The Ocelot system was not designed or intended to be used as a super-fast burner.  My 2 cents.

[Jeff McWilliams]

Hmm.  Yeah, this clarification on use limitations wasn’t expected.  I ordered one for a BRS-3000T to play with.  I’ll keep it, and laminated a printed note regarding its use so that I don’t forget.

[Jeff McWilliams]

For upright canister stove users looking for a wind screen solution, there is one other option on the market, and that’s the Optimus clip-on windscreen.

https://www.optimusstoves.com/us/us/93-8018907-optimus-clip-on-windshield

At 87g, it’s gonna be heavier than the Ocelot, but it may be less finicky.

[Roger Caffin]

The Optimus windshield is more solid, but I found that sort of thing a bit difficult for packing.

And the little piezo lighter shown in the pic turned out to be almost useless for me. Not enough energy in the spark.

Cheers

[Jeff McWilliams]

Roger – I agree.  According to their web page, the Optimus windscreen is designed to so that the Optimus Terra Weekend HE pot nestles inside it and the two pack with minimal wasted space.  The Terra Weekend HE cookset is a 0.95L heat exchanger pot and a matching frypan with detachable handle that doubles as a lid for the pot.

I’m certain that there will be a size disparity and a less than ideal nesting when this windscreen is used with a typical 750ml titanium pot, or any other pot that doesn’t match the diameter of the Terra Weekend HE pot.  For example, my other favorite 2-person pot is the Evernew ECA252R, which is what I use for 3-season trips with your winter stove.

 

[Roger Caffin]

The other problem with something like the Optimus windscreen is that it is designed for one size of pot only. For instance, it would not fit the standard 1.5 L Ti pot I use when cooking for the two of us. I prefer a bit more flexibility.
But, HYOH

Cheers

[Jeff McWilliams]

What I find most fascinating about the Optimus windscreen is its method of attachment.  Apparently that lip around the valve is some sort of standard, which is also something your remote stove sort of relies upon to form a tight seal.

I wonder if some engineer much smarter than me could design a windscreen that attaches similarly, but when not in use folds down to a more compact shape.  The pro of such a design is that it’s not dependent on specific stove designs and very specific ways of slotting tabs into the pot supports like Jon’s design does.

No offense to Jon.

Roger – I’d also argue that the if you could only choose between the Optimus windscreen and the Ocelot to use with your 1.5L pot, chances are good that the Optimus one would work and the Ocelot wouldn’t.  The Ocelot will only work with pots of a specific diameter or smaller, and of a specific height so that the handles clear the cutout.

On the other hand, the Optimus windscreen is a half circle.  There are no pot handle clearances to worry about, and I’d argue that when cooking it would fit a wider range of pots than Jon’s.

We’ve already discussed the problems with stowing it compactly in one’s pack.

 

[DAN-Y]

What I find most fascinating about the Optimus windscreen is its method of attachment.  Apparently that lip around the valve is some sort of standard, which is also something your remote stove sort of relies upon to form a tight seal.

That’s a very interesting way to attach a windscreen. A quick search found this:

[Roger Caffin]

>> Apparently that lip around the valve is some sort of standard, which is also something your remote stove sort of relies upon to form a tight seal.

It is an undocumented standard, in that the Lindal Group make all their fittings the same way. That rim is crimped onto the canister with a rubber seal concealed inside the crimp. That rim is the same on most gas canisters, fly spray cans, spray paint cans …. That means that the same crimping machine works on all of them, which is a huge manufacturing advantage.

Yes, I use that rim to lock my canister connector onto the canisters. It’s very reliable.

As for the balance between the Optimus windshield and the Ocelot – I would argue that neither will suit my pots. Yes, the Ocelot has a limited range of acceptable pot diameters, but so does the Optimus one. If the pot is too big, it won’t fit either. My Ti pot could be called a ‘2-man’ pot, and is too big. But my foil windscreens adapt to all sizes of pots. I am going for flexibility here.

My V2 stove, but it could be any stove you like.

My V4 stove, but again, it could be any stove. I am using these photos because I have them. Note that in each case the windscreen can adapt to different sized pots: that is what I am driving at.

Cheers

[jscott]

Again, I use the outer portion of a Caldera Cone as a windscreen. It’s super light and essentially does what Roger’s windscreen does, but I didn’t have to make it. In addition, i could use it with tent stakes as a support to light a twig fire for cooking if my stove failed or, ahem, ran out of gas.

Never happened!

That said, I use a Pocket Rocket, so Jon’s system is even better, I think. Less bulky.

[Jon Fong / Flat Cat Gear]

So, it has been a fun project so far! I will be releasing a video with updated messaging shortly. As I delve further into this, I learn a lot more about things. I like the Optimus Clip on Windscreen, but in the back of my mind I kept thinking about the Moulder Strip. I found this article:

Primus offered a similar 2 oz clip on windscreen and then pulled it off the market as it regularly overheated the canister

In reviewing canister topped stoves, the power output (not delivered power) ranges from 2700 watts to 3400 watts.

For the Ocelot Windscreen, right now it is being designed for about 1000 watt output.  It is being designed for people who use mugs (750 ml and smaller).  The trick will be in training people to use a lower power setting.

 

The nice thing is that with a Snow Peak Trek 700 and the TOAKS 750, you can store all of the windscreen as well as a 4 oz canister.

    

 

More updates soon. – Jon

 

[Roger Caffin]

>> The trick will be in training people to use a lower power setting.
That is THE problem.
I have zero faith that the ‘average user’ will have even read this message.

Users in a hurry will simply turn the stove up to full bore and … there will be accidents, disasters, and possibly law suits. With an expensive lawyer ranting at you in court, and the only-too-common ‘deep-pockets’ theory, your outcome may be perilous.

Actually, I am not that worried about the ‘average’ user. I worry about the fringe, the complete idiots. Too often they have affluent parents only too willing to sue.

Cheers, or otherwise.

[Ken Larson]

UPDATED Ocelot: PocketRocket 2 & PocketRocket Deluxe

Recommend that you run the stove at about 50% , but the new model will tolerate higher power levels (the fuel efficiency drops off).

“Here are wind tunnel test results from the PocketRcket Deluxe. The test was run at ambient as weill as with and without the Ocelot windscreen. In all test, 2 cups of 70 F water was used and heated until boiling (210 F at our elevation). At 3.5 mph wind, the Ocleot Windscreen saved 5 grams of fuel per boil. In all cases, the stoves were turned to 1/2 power, increasing the power, lowers the fuel efficiency.”

[H W]

Jon — I rec’d the system for my MSR PR 2. I have the Toaks 750 (4″ diamater) and while the screen nicely wraps around the inside the burner plate does not fit as shown in your image. Is that for a different setup?

[Jon Fong / Flat Cat Gear]

Here is my TOAKS 750 ml mug (ID=3.75).  That is withthe bigger original windscreen and not the newer one wich is smaller.  Jon

[H W]

Yes I can do that but the pic with the fuel canister inside the Toaks threw me. Clearly the canister will fit with the screen but not with both screen and plate. Not really an issue for me. Appreciate the followup email regarding the 50% rule.

[Jon Fong / Flat Cat Gear]

HW,

Per my email that went out this morning, the small tabs need to be bent to about a 45 degree angle.  That allows the burner plate to slide further down into the mug.  The burner plate is positioned just like in he picture.  Invert the fuel cnaister and it should slide down into the mug.  There will be a little springiness to the assembly: you may need to snug the whole thing together with the stuff sack, but everything just fits.

[Jon Fong / Flat Cat Gear]

We tweaked the design of the Ocelot Windscreen a bit: more space between the windscreen and the valve as well as reduced the windscreen height.  It turns out that you only need a narrow band of protection to keep the flame in direct contact with the mug.

More data was collected on the BRS 3000t and wind tunnel testing really demonstrates how much this stove is impacted by the wind.

 

We were unable to conduct default boiling test above 3 mph and had to reduce the speed to 2 mph.  The comparison is pretty dramatic:
Bare BRS 3000t at 2 mph – 2 cups boiled using ~18 grams of fuel
Ocelot BRS 3000t at 3.6 mph – 2 cups boiled using 10 grams of fuel

Ocelot windscreens weight just under 1 oz. and stores inside your mug (additionally, we have also been able to store a 4 oz. gas can with the system in 750 ml mugs).

We are currently supporting the BRS 3000t, PocketRocket 2, PocketRocket Deluxe and Fire Maple 300T.  We just completed the prototypes for the Original PocketRocket as well as the Soto Amicus.  Best regards – Jon

Recently completed videos

[Jeff McWilliams]

Did the updated design ship to current customers yet?

Numbers look great!

[Jon Fong / Flat Cat Gear]

Yep (First Class Mail), you should be receiving them, shortly.

[Russ W]

I received my BRS replacement this evening and immediately assembled and fired it up. No wind a blowing tonight so I can’t comment on the wind performance and I haven’t weighed it because my scale was unavailable, but wow what an improvement in size, weight and fiddle factor.  Improved to the point that I’ll probably actually take and use it. Well done Jon!

[Jon Fong / Flat Cat Gear]

Have fun on the trail and let me know how it works for you.

[Jon Fong / Flat Cat Gear]

You can dry bake in the wind with a canister topped stove using the Ocelot Windscreen.

 

[Roger Caffin]

What does the bottom of the Ti outer pot look like?

Was it sitting on that rather burnt-looking plate on the stove?

Did you have a spacer under the inner pot?

What did it taste like?

Cheers

 

[Jon Fong / Flat Cat Gear]

Was it sitting on that rather burnt-looking plate on the stove? Yes, there is a diffuser plate between the stove and the bottom of the mug.  As you can see the diffuser plate will oxidize and even out the heat to the bottom of the mug/pot

What does the bottom of the Ti outer pot look like? Since I am using the diffuer plate, the bottom of the mug looks normal.

Did you have a spacer under the inner pot? no spacer.  The heat transfers from the mug to the bottom of the pan (thick walle daluminum)  then up the sidewalls to cook goods.  That being said, the top will not get brown.

What did it taste like? – Outstanding of course

I bake on the trail all of the time, here is a quiche at Hamilton Lake in Sequoia NP.

 

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