MSR Whisperlite Universal flame control question (Roger Caffin please read)

"The great simmering MER Dragonfly stove"

What the heck is this?

–B.G.–

If you heat the stove up, then turn it off, then turn it back on and light it when it's still hot, that's how you generate a hair singeing flame ball.

Why don't you just pump one or two times, start stove. Why does it need to be fully pressurized to start?

@ Bob> So I made a little typo. It's been corrected. Hey, so I'm dyslexic (deslics?, klisdsick?)

@Jerry> Just listing the procedure MSR suggested. I guess it's necessary to pump it up more to get it properly pressurized to get it started. Then, once hot, it can be "de-pressurized" and re-started.

"Why don't you just pump one or two times, start stove. Why does it need to be fully pressurized to start?"

Exactly.

This is not exactly the same stove, but it is close. I got very handy with an MSR XGK one time. White gas, of course. I could pump it just once or twice, open the valve just slightly, and only about one drop of fuel would bubble up, and I lit it that way. Very low pressure, very low priming, very low fuel waste. I could run it very low to high, whatever I wanted. But it took some practice.

–B.G.–

Don't worry, Eric. –G.B.– is the only one here that ISN'T dyslexic, so it's his job to be the hall monitor to correct us lesser ones. Remember, there might be children reading the forums, and we need to set a solid example when it comes to spelling, syntax, and profanity. Ranting on and on about guns, religion, and cuben kinkiness is fine, but we mustn't be dyslexic. It sets a bad example for those in their formative years (like Doug).

I quit using my MSR Whisperlight Universal 10 years ago because I got tired of singeing my eyebrows. Very heavy too. And the smell of white gas is very obnoxious.

Honestly, I would question how well it would simmer even then. And yes, I have one and use to use it all the time. I could simmer with it as long as I constantly controlled the flame. Once I got use to how long the change took I got pretty good at it. However, it's heavy and a pain to constantly have to adjust so it's just extra equipment that I never use now.

Having a control at the stove works much better.

You asked Roger to read maybe you could ask him to respond :)

Yeah, been waiting for dog's response with bated breath. Maybe he's off on a "tramp" somewhere on one of NZ's "tracks".

Roger, please respond. All is forgiven.

Yeah, I was 'out'. Now I am back.

Well, I never got the Whisperlite to simmer really well, but as so many others have noted, a low pressure does help. That said, it IS possible to simmer with a high tank pressure IF you are really careful with the valve. Tricky though – very touchy.

Now, the Dragonfly valve. Never mind the shape, what matters here is where the actual needle valve and seat are, relative to the gas and liquid flows. If the needle valve is in the liquid flow you will have trouble with simmering, because the control is so touchy. Remember, the liquids expand to about 250 times the volume. But if the needle valve is in the gas flow you have far easier control and also far faster response between the valve and the flame.

Once the Dragonfly stove has been primed and warmed up, the needle valve, which is right near the jet, will be in the gas flow. That means it should give good simmer control.

Could you modify the Whisperlite this way? Um.
I'll say yes, but it is going to take a bit of careful engineering, some machining, and some high-temperature brazing or silver soldering. On the Dragonfly the fuel goes down the 'valve tube' to the jet without needing a 'preheat tube' over the top. That's because the Dragonfly is a vortex stove and the jet region gets stinking hot. The tube going to the jet IS the preheat tube.

However, on the Whisperite there has to be a preheat tube going over the top in a curl. So any needle valve you want to add near the jet will have to be sited in the jet base on the opposite side from the gas tube, OR you will have to use a modified version of the Dragofly valve tube. You could make one.

Mind you, predictably, I will point out that a winter canister stove does this preheat business far better. "He would say that, wouldn't he?"

Cheers

First of all, Eric I just received your messages. I too have been sequestered fighting off microscopic villains all week. And the PMs always seem to deny your existence.
Roger Caffin, thank you for your input and consideration. Especially seeing you are amongst the Fearless Leaders. I think this may be my first post here.
I primarily wanted to acquire Erics Dragonfly was to compare valve components. I have from the start have always been a SVEA 123 fella. That brass finish, and yep, a little bit of heff. One is also carrying some liquid fuel here donchyano. And wouldn't you know I could simmer seemingly all day. However I always lusted for the whisperlite. I was finally given one and was disappointed because its lack of simmering. I was able to improve this by making flame deflectors and adjusting the generator shape. In the meantime I found a Simmerlite which improved the simmering but not nearly enough.

But that Simmerlite had a huge valve difference. Being an older stove possibly safety was not as intense as litigious pressure. So much for safe procedures vs so called progress. (huge debate issue here)
The older, more needle type valve, of the Simmerlite
Let me temporary summarize here with some partial conclusions without elaborating on combustion engineering (or what I might know about it) or other measurements both mechanical or chemical I am attempting to make.
The older whisperlite tank valve had or seemed to have a truer "needle valve. The further you opened it, the more fuel passed. The rate per turn depended on the size of the needles" seat hole size, the taper of the needle and the thread pitch.

The newer "valve seat" doesn't have this seemingly simpler mechanism and the primary seat appears to be a nearly flat plate followed by a tapered plug with what appears to be a mixing vortex. I assume this is not
part of the vortex process you're referring to RCaffin. It seems to plug into a similar shaped cup at the end of the valve body. MSR denied any air/fuel mixing at the bottle pump.

Someone (i am looking for it again) posted a similar discovery and modified the brass tapper and improved simmering performance. However, this may have diminished parameters.

I think the 123 will simmer well because the jet cleaning pin the rises at the end of your valve conveniently changes the jet size.

Lastly forgive me if I have stepped out of bounds on this tread. I have collected much more information and would appreciate any input. I had planned to open a topic on this very subject.

Hi Bryant

> The newer "valve seat" doesn't have this seemingly simpler mechanism and the
> primary seat appears to be a nearly flat plate followed by a tapered plug
That's fine. Quite a few 'needle valves' in industrial use are like that. They don't have to look like needles.

> with what appears to be a mixing vortex.
Not sure what you are referring to here, but I don't think so.

> MSR denied any air/fuel mixing at the bottle pump.
They are 100% correct. The mixing ALL happens after the gas comes out of the jet.

> forgive me if I have stepped out of bounds on this tread
Chuckle. Apart from having to be polite, there aren't many 'bounds'.

Stove freaks of the world unite – you have nothing to lose but your white gas.

Cheers

What I'm going to try t do – once I acquire the Whjsperlite Universal – is try to get MSR to sell me the Y-shaped Dragonfly stove valve. I'll sign any legal disclaimers they need.

Then, with some machining, and threading and/or soldering if necessary, I want to make this valve "plug into" the W. U. between the stove and the Coleman gas fuel hose. I will NOT change any original W. U. fittings to make this work. It must absolutely be a "modular" piece or why do it in the first place?

Then, after burning candles at church and saying enough Hail Marys and Our Fathers, I will hope to hell it actually permits the W.U. to simmer very low. (Actually I'm Episcopalian – Anglican to Roger – but I'll use any petitions I can to get it to work.)

Yeah, the vapor generation systems of the two stoves are different but it's the liquid fuel feed I want to regulate, just as in the Dragonfly.
Am I still understanding the physics involved clearly?

BTW Roger, I did not mean to type "… dog's response." I meant to type "… Rog's response." No offense meant. I'm a fumble fingers on a keyboard.

Hi Eric

> some machining, and threading and/or soldering if necessary,
NOT soft solder I hope!!! Silver solder, OK.

> after burning candles at church … I will hope to hell it
Um – aren't you mixing the two sides up a bit here?

> it's the liquid fuel feed I want to regulate,
Huh??? In that case, why not use the valve at the bottle?
I do not understand. Sounds all wrong to me.

Cheers

Roger,

Either I misunderstand the physics of the Whisperlight Universal and the Dragonfly or "there is a failure to communicate" here.

I thought the (Coleman/white gas) fuel was liquid UNTIL it was vaporized in the arched tube over the side of the burner.
If that is so then any modified Dragonfly STOVE valve would be regulating liquid fuel from the fuel bottle to the burner. NO?

Am I missing something here??

BTW, yes, the only solder I own and use is high strength "silver solder". By US building codes the old, mainly lead, solder may no longer be used for joining metal pipes.

In many MSR stoves that burn white gas, there is a fuel tube that connects the fuel bottle with the burner, and there is a piece of stranded wire cable inside there. Once the burner is hot, the cable carries heat from the burner back through the fuel tube toward the pump. That heat serves to start the pressurization and vaporization process (in the fuel tube).

–B.G.–

Eric, I think the idea is that the standard valve at the pump is a needle valve, so you would just be adding another needle valve. But it might be true that the Dragonfly valve offers finer control.

Hi Eric

> Am I missing something here??
Yep.

Your basic idea is correct: the arched tube or 'generator' as some call it is meant to be where the liquid white gas is turned into a vapour: where the vapour is 'generated'. However, the design of that arched tube dates back to kero stoves, and kero is MUCH harder to vaporise. So some serious heating was necessary with the older kero stoves to generate the vapour.

But white gas is a bit different from kero. White gas contains some rather volatile components, including (believe it or not) BUTANE! So it is much easier to vaporise. The tube over the top gets almost red hot, sure, but a lot of that heat travels back up the line to the valve and even to the inlet hose. There is enough heat energy before the valve that the fuel going through the valve is a vapour, not a liquid. Well, once the stove has been fully primed that is. This is one reason why you don't see many kero stoves in the field these days: its much harder to use.

Now, follow that argument a bit and you end up with a canister-fed winter stove like mine. There's enough heat going back through the stove body and the valve that the fuel is fully vaporised before it gets to the needle valve. Yes, that takes a tiny bit of priming to happen – but tiny.

Cheers

Great discussion. I'm rounding up some drawings, pictures, measurements and a few calculations to post. I've really thought too that adding the second valve but thought that the added hardware might be excessive. I really think that that modification of the original stem might be their way to go. The goal is to make it more of a traditional metering needle valve with a much finer control. And, again, what is that vortex spiral so accurately milled into the nearly cylindrical needle doing? The only passage out of tbis part of the body is a 1/32“ chord milled across the ¼-32 thread that advances the stem.

Whooa! I am conjuring up flashbacks of too much incense and now am considering trying to burn paraffin in the whisperlite. I have a can or two from the military supply room.

> what is that vortex spiral so accurately milled into the nearly cylindrical needle doing?
Probably part of the heat exchanger which vaporises the fuel. It's not unique.

Cheers

Roger,

In the case of the MSR Dragonfly stove (in Coleman white petrol mode only) does the stove valve regulate vaporized white petrol or liquid – after the stove is at full chat? You seem to be saying it is meant to work with vaporized petrol.

What I'm asking is WILL the Dragonfly stove valve work once adapted too the Whisperlite Universal fittings on each end??
By "work" I mean make the MSR W.U. stove simmer as low (or nearly so) as the Dragonfly? i. e. would I be wasting my time and effort trying to do this?

I realize the W.U. comes with 3 fuel type adaptors, canister, white gas/"petrol", and kerosene. I'd say if my conversion works with petrol it should work with kerosene.

Hi Eric

Caution: I have not fired up a Dragonfly for years – nor have I fired up a Whisperlite for that long either!

> In the case of the MSR Dragonfly stove (in Coleman white petrol mode only) does the
> stove valve regulate vaporized white petrol or liquid – after the stove is at full
> chat? You seem to be saying it is meant to work with vaporized petrol.
I am fairly sure that once the Dragonfly stove has been primed and is running at normal working temperature the valve will be throttling VAPOUR.
'Fairly sure', but I could be wrong, depending on ambient conditions.

> WILL the Dragonfly stove valve work once adapted too the Whisperlite Universal
> fittings on each end??
Short answer: I don't know. You would have to test it out. For sure, you would need to use a windshield around the lot.

> I'd say if my conversion works with petrol it should work with kerosene.
Um – doubtful. If (and I really do mean IF) it works with kero then it WILL work with white gas, but getting it to work with kero would be much harder. I think kero needs a temperature about 150 C more (+/-50 C) than white gas to vaporise. For kero I think running the fuel through the hose over the top will be essential. If you can put a valve between the jet and the preheat tube, that would work. The Coleman Peak Apex II did that, and it was a very good kero stove.
Except for the time I spilt hot milk over the Apex preheat tube, thermally shocked all the built-up gunge off the inside of the preheat tube, and terminally clogged the jet – in the snow. Cold dinner that night. Sue was very understanding.

Cheers

Eric, I can't help wondering Why? if you want a nice controllable white gas stove why not just get a Dragonfly?

Ha, Paul. I just purchased Erics Dragonfly. I'm in the process of analyzing it's operation. What I noted so far is that the bottle/pump valve is spring loaded with a hemispherical seat. This in combination with the back pressure from a vaporized (expanded) fuel and the jet does act as a regulator of sorts. The real fine control comes from the needle valve at the chamber preceding the jet.

The newer pump valves have very little taper so essentially end up being an on/off and not a metering valve. Unfortunately I think the main reason for MSR moved away from this is there are soooo many parts. More parts mean high failure rates and problems.

In an attempt to get the Whisperlite international to simmer I added coil springs around the vaporization tube to add surface area and gather more heat from the lower flame. This helped but it still has not much more than a few seconds of rotation at the pump valve to go from simmer to full flame. Using a pump/valve assembly from a Simmerlite (discontinued) which has a finer tapered valve seat at the pump increased the control to almost a half an turn. Incidentally the Simmerlite doesn't simmer well either. Both the Simmerlite and Whisperlite have really nice flame spreaders. They are lite and simple. I have yet to try running the Simmerlite or Whisperlite using the Dragonfly pump valve. Currently the one I tried has a stem leak. Possibly a piece of hair or bad O-ring. My feline friend insists on assisting me until the flames rise.

I hypothesize that with a finer taper valve at the bottle one should be able to lower the flame easily however the response time will be no where close to instant. In addition adding a set screw into the bottom of the final vaporization chamber to raise the jet cleaning pin into the jet effectively making it smaller will also bring the stove to a simmer. This appears to work well with a SVEA 123 however I anticipate the air fuel mix will be off and adjustments would be difficult as well as the probability for leaks will be high. This too might be compensated for by choking off the air intakes in the stove body. I have begun to fab a choke using a piece of copper tubing. This choke mod should also allow me to burn alcohol in the Simmerlite and Whisperlite.