Not-So-FAQ

[Loafer]

Ok here's one.

 

When I refill my Squirrel in the mornings, clean out the ash and open the bottom door to get it going again properly, within about 5 minutes, there begins a deep 'organ-pipe' type noise which gets louder and louder until I rush to the bottom door and close it. It can be heard clearly outside the boat, too.

 

Anyone else experience this, or can offer an explanation as to why my chimney should resonate so?

 

Thread drift acceptable!

[John V]

flue gasses igniting in the flue pipe......sort of stationary pulse jet .......the Loafer Doodlebug perhaps ?

[Loafer]

flue gasses igniting in the flue pipe......sort of stationary pulse jet .......the Loafer Doodlebug perhaps ?

 

I like your name for the phenomenon, but why should flue gases ignite, when they've just left a really hot place with plenty of air?

 

It has reminded me on a couple of occasions that I left the bottom door open, so I quite like it happening!

[John V]

If I understand how they operate correctly, a fuel rich mixture ignites in a tube, uses up the available oxygen causing momentarily a partial vacuum. This sucks in fresh oxygen through the top of the flue and fresh fuel rich gasses in from the bottom which then ignite again. ad infinitum

[Higgs]

Ok here's one.

 

When I refill my Squirrel in the mornings, clean out the ash and open the bottom door to get it going again properly, within about 5 minutes, there begins a deep 'organ-pipe' type noise which gets louder and louder until I rush to the bottom door and close it. It can be heard clearly outside the boat, too.

 

Anyone else experience this, or can offer an explanation as to why my chimney should resonate so?

 

Thread drift acceptable!

 

 

It's just the harmonics of the flue pipe. Similar to an organ pipe or blowing across the top of a bottle. Gets stronger with the rising force/speed of the exhaust

[Loafer]

Rightho, I can believe all the above, thanks!

 

Second part of my query though: Does anyone else experience this?

[Higgs]

Rightho, I can believe all the above, thanks!

 

Second part of my query though: Does anyone else experience this?

 

Yes.

[Nightwatch]

We get it with ours. I think it is air rush, combined with the increasing heat within, the fire is burning air faster than it can be fed.

 

At that stage I would be reluctant to experiment by opening the glass door. And no, I haven't tried.

 

In a house years ago we. Have a oil drip fire in the living room. One day it went out. Unbeknown to me was that oil was still dripping in, created a nice little pond of oil. I lit it again and within five minutes we has a very hot, rumbling,shaking fireplace with flames disappearing up the chimney. We were very close to calling the fire brigade, but thankfully the oil burnt of and calm was restored. Phew!

 

Warmed the room up nicely.

[John V]

I had it when I had a flue fire, (too much resinous wood being used)

the flue glowed cherry red with all the vents closed.

The roar was deafening and there was 3 foot pulsing flame screaming out of the chimney.

not an experience I care to repeat

[Loafer]

I had it when I had a flue fire, (too much resinous wood being used)

the flue glowed cherry red with all the vents closed.

The roar was deafening and there was 3 foot pulsing flame screaming out of the chimney.

not an experience I care to repeat

 

Cor lumme. It's not an experience I want even for a first time!

[cuthound]

Knowing Loafer's previous career, it probably the sound of his after-burner

[RLWP]

DON'T DO THIS WITH A PLASTIC DRAINPIPE

 

If you take a piece of newspaper, screw it up and push it into the bottom of a drainpipe, then set light to it, you get exactly the same effect

 

Richard

[Loafer]

DON'T DO THIS WITH A PLASTIC DRAINPIPE

 

If you take a piece of newspaper, screw it up and push it into the bottom of a drainpipe, then set light to it, you get exactly the same effect

 

Richard

 

Wow. I never knew that! I can remember bits of stuff at college though, using lycopodium powder in a Kundt's Tube (I always loved that name!)

[David Mack]

 

Wow. I never knew that! I can remember bits of stuff at college though, using lycopodium powder in a Kundt's Tube (I always loved that name!)

I remember our rather shy and unconfident Physics teacher teaching a class of adolescent boys about that. He kept pronouncing it as if there was no letter 't' in the word.

[Harpur Hill]

DON'T DO THIS WITH A PLASTIC DRAINPIPE

 

If you take a piece of newspaper, screw it up and push it into the bottom of a drainpipe, then set light to it, you get exactly the same effect

 

Richard

When I was a wee chap the big kids used to do this up the external house drain pipes - they called it a bull roar.

 

HH

[RLWP]

When I was a wee chap the big kids used to do this up the external house drain pipes - they called it a bull roar.

 

HH

 

The seventy year old I learned this from had done it as a child

 

Richard

[Loafer]

It's the only element of 'A' level physics that used to cause a lot of guffawing on the back row.

 

Later in life, it was the morning met brief with a hall full of aircrew. We used to love it when the air mass was going to be 'warm and moist'!