Fan powerd stove

[Hiker]

Hi everyone

Following on from my query about the sierra zip stove i was advised to have a go at making one so i must say a big thank you to Scoops , Glen and Cyclist for sending me links and introducing me to the world of stove building its been really interesting and a lot of fun so thanks lads.

After trying out different sized paint tins i settled on the 500ml paint tin its 4 inches long and 3 1/2 inches in diameter for the inner burn chamber i used a standard size dog food tin 400gr its not a perfect fit so i took a jubilee clip and cut it down to fit around the outside of the burn chamber with a bit of pushing and shoving it goes on and makes a really tight fit

The burn chamber has 8 holes around the bottom of the can and 4 holes a third of the way up the can oh and the burn chamber has been cut down to 2 1/4 inches long

The fan was taken from a old computer i simply glued some legs on the fan so it stands about 1 1/4 inches of the ground and the stove its self stands about 3 inches of the ground

The legs on the stove spin round so it can be packed away just a little tighting up of the screws to set it back up again and the fan packs away up into the bottom of the stove its really compact and will fit into the billy can of choice as its so small .

Ok now for some pics , ive only tryed it out in the garden and it performed great i am going up the lakes at the weekend so i will give it a good run out then.
this is with the fan swiched offand this is with the fan swiched on just look at it go a nice brew coming up

So there it is i hope it a makes sence and thanks for looking .

Hiker

 

[anthonyyy]

Very interesting, I think I'll have a go myself. Dosen't the fan get hot? Whats the gap on the bottom between the inner and outer can?

 

[kram245]

well done hiker, looks good. Some pepole slag off the concept, but i have a titanium sierra stove and think they are great.Like to hear any follow ups you have, chees mate, Mark

 

[scoops_uk]

Top stuff Hiker

I can't actually see the picture, but no-one else seems to be having problems so it must be something to do with me!

So have you started planning a Mk II version yet? Once you start you just can't stop!

Edit: Aha! there's a little underscore after the off that links to the piccy, marvellous stuff, looks to be going well. :You_Rock_

Scoops

 

[rik_uk3]

Very nice indeed, I may have a go myself

 

[Glen]

Good stuff Hiker, make a very satifying cuppa when you've built them yourself don't they

I really like :
The spinning legs idea for a bottom blowing fan design.
The pot support/windshield is a really nice simple design.
Easily avialable components, I suspect most could be got for nothing.
Could probably be made using only a multitool.

Perhaps the biggest compliment is that straight away you've inspired several people to have a go at their own.

 

[cyclist]

well done. Now you´re a proud member of the brotherhood of firemakers.

Let´s not forget fire science - what´s about the stove´s data?
Weight?
Fuel consumption?
Time to get a rolling boil in different containers (Trangia 0.6l kettle, 1l pot etc.)?
Fuel consumption and boil time with fan off?
Cost (based on time to fabricate and your income)?

 

[Hiker]

Thanks for the replys everyone

Anthony that was allways my biggest fear the fan getting hot or even melting at the moment the gap between the inner can and the bottom of the outer can is 1 3/4 inches and another 3/4 of a inch to the fan its self making a total distance of 2 1/2 inches , i ran the stove for around half an hour and the fan was warm to the touch but there was no sign of melting and the fan worked as normal but it would be better if the fan and the burn chamber were further apart .

And this is where the mk2 comes in Scoops , because i want to keep the stove size and the burn chamber as it is , my plan is to slot a 3 inch section of can up the inside of the bottom of the stove that will drop down into postion when set up giving a greater distance from burn chamber to fan but i will need the next size up brackets for the legs so the stove will stand another 1 1/2 inches of the ground ,

Just had a tinker heres a pic just needs longer legs now oh and the drop down can is a large tin of peas incase you want to have a go at this method the fan still packs away up into the stove as shown here

I i could lower the fan a little but there is a critical point were if the fan is to close to the ground it sucks the air downwards at the moment my fan stands 1 1/4 inches of the ground , or shorten the depth of the burn chamber ive seen examples of stoves on the net were the burn chamber was made from a tuna can and they are not even 2 inches deep at the moment my burn chamber is 2 1/4 inches deep i would like to keep it like this so thats why im trying the drop down can method and lengthening the legs . I could just put longer legs on but i would loose lots of air out the sides with the drop down we can channel the air to where we want it .

Glen your spot on all the components are easly availible and replacible and cost very little money , i visited the local pound shop i got my paint tins from there i noticed while in there they had tin snips nuts and bolts the legs on the fan are from a geometry set a ruler cut down , the only things i didnt see to build this stove were the fan and the brackets for the legs , i think its possible to make this stove for £5 ive seen the fans on e bay going for £2 paint tin £1 burn chamber for free open a tin of soup or dog food any plastic will do for the legs leaving £2 for the brackets for the legs

Stove data
ill get back to you with this Cyclist when ive done more tests

Hiker

 

[Hiker]

Sorry i sent the wrong pic heres the stove packed away

 

[anthonyyy]

My ideal fan would be a battery operated pump that fed the air through a metal tube. It should give you great flexability with regard to location of the pump, use on different stoves/fires etc. You can get ones for pumping up air beds but they are 12 volt.
I'm thinking of trying out an aquarium air pump, but I assume the airflow would be very low. They are fitted with plastic tubing - I would just attach metal tubing to the bit near the stove. I had the idea of a coil of tubing with micro holes right in the centre of the fire.

 

[scoops_uk]

Anthonyyy - Not sure an aquarium pump actually pushes out enough air and they're quite heavy. They're more about pressure than volume whereas with a stove you want volume! Interesting idea of having a coil releasing the air into the heart of the fire though.

Hiker - As an alternative, you could fit a fan onto the end of a short length of 50mm aluminium corrugated tubing, or similar, so you could keep the fan away from the heat. This might also give the advantage of allowing you to pull air in from the side rather than up from the ground, maybe allowing better flow and possibly curing any downdraft problems from trying to pull air under the stove to then push it up through the burn chamber?


Is the MkII going to have a solar fan? ;-)

 

[Eric_Methven]

A small impeller fan would do the trick. An aquarium diaphram pump definitely won't. There's nowt wrong with the old computer fan though. The fact that it is blowing air into the fire will keep the heat away from the fan. Just slide it out of the way when it's not needed. One thing I've been working on is a bicycle dynamo with a geared up hand crank, so you can deliver sufficient power to the motor when the battery runs low, or you don't have any left. The added weight is a problem though as the whole idea is to save weight by not needing to carry fuel.

Eric

 

[Glen]

One thing I've been working on is a bicycle dynamo with a geared up hand crank, so you can deliver sufficient power to the motor when the battery runs low, or you don't have any left. The added weight is a problem though as the whole idea is to save weight by not needing to carry fuel.

Eric

I figured one of those wind up torches with a mobile phone charger output would do the trick nicely and given the duel purpose not make me worry too much about the extra weight.

 

[cyclist]

My ideal fan would be a battery operated pump that fed the air through a metal tube. It should give you great flexability with regard to location of the pump, use on different stoves/fires etc. You can get ones for pumping up air beds but they are 12 volt.
I'm thinking of trying out an aquarium air pump, but I assume the airflow would be very low. They are fitted with plastic tubing - I would just attach metal tubing to the bit near the stove. I had the idea of a coil of tubing with micro holes right in the centre of the fire.

the aquarium pump has to work against pressure (the water in the aquarium) while a fire charger has to deliver air flow at low pressure. Compare a water pump to the compressor part of a turbocharger.

Don´t get me wrong, I like the idea of a supercharged woodfire a lot. Having experiment with all sorts of fan stoves made it sure IMHO how good those Volcano Kettles are: no wiring, no motor, no parts to fail, just using thermal energy to bring the combustion air to the fire is pretty smart.
Why not design a wood (or meth.) stove with a burning chamber with intake and exhaust ports, Install a turbocharger or a Comprexcharger. Or have a look at the fire place in the house ......

 

[anthonyyy]

Anthonyyy - Not sure an aquarium pump actually pushes out enough air and they're quite heavy. They're more about pressure than volume whereas with a stove you want volume!)

A small impeller fan would do the trick. An aquarium diaphram pump definitely won't.
Eric

I’m sulking now
Thanks for your feedback lads.



I do realise that they are designed to deliver pressure rather than volume but I still feel it might work.
There could well be an other pump out there that would be better but I can’t think of any.


Blowing air via a tube does give you greater flexibility. Ever tried to use a Kelly Kettle in a tipi for example – bloody slow. If my idea works the same equipment could be used for any solid fuel stove.

I would appreciate it if anybody has an idea for a battery powered pump to which a metal tube can be connected. A Google search for “air pump tubing battery” just brings up “aquarium pumps.”

(Sorry for hijacking Hikers stove by the way)

 

[cyclist]

There could well be an other pump out there that would be better but I can’t think of any.
Blowing air via a tube does give you greater flexibility.

actually there´s a very powerful pump you have with you all the time: your lungs. All you need is a tube to get the fire started www.trailstove.com/details.html

Ever tried to use a Kelly Kettle in a tipi for example – bloody slow.

depends on the fuel.
Make sure combustion air is cooler than exhaust gas and make sure it´s cold inside the tipi (just kidding ) - you made a good point. Try a pantry outside the main living room of the tipi e.g. vestibule. and of course the performance of every stove depends on the oxygen-fuel-mixing rate. For a woodstove small twiggs are the stuff you want: simply because of the increased surface compared to bigger branches. Downside: you need more fuel ....

My conclusion: a supercharged woodfire has a lot of pro´s and con´s. For me and the way I use a stove there are more con´s while other users have other priorities