Sponge cake with only three ingredients - will this work at all? I have a recipe for a sponge cake only consisting of sugar, eggs and flour. To be honest, I am a bit afraid to to try it.

How can this create a fluffy cake - where does the air come from? Won't it be really dry because there is no fat in it?

Also, when doing a cake like this, do I need to pay special attention to something? I am really skeptical that this will work.

How long can I store the undecorated cake? Where and how to store it?

Edit:

Ingredients


6 large organic eggs
180g caster sugar
180g plain organic flour (sieved)


Method

Preheat the oven to 170°C.
Break 6 eggs into a very clean bowl of a stand mixer fitted with a whisk attachment. Whisk the eggs gently to break them up, then add the caster sugar and whisk on medium high speed until the ‘thick ribbon’ stage is reached. This means the mixture will be light, have increased substantially in volume and be of a moussy consistency. When you lift the whisk the mixture should fall slowly in thick ribbons.

While the eggs are whisking, grease three (22cm diameter) cake tins and line the bottom with a disk of parchment paper.

When the thick ribbon stage is reached, add the sieved flour and fold in very gently to fully incorporate without knocking the air out of the mixture. Very carefully apportion the mixture between the three cake tins and pop in the oven for 15-20 minutes, turning two thirds of the way through the cooking time. You will know when they are ready as they should be golden brown and coming away slightly from the edges of the tins.  Remove from the oven and cool in their tins for 10 minutes before carefully turning out and leaving to cool completely on a wire rack.

source
The key to this cake is the whisking of the eggs and sugar to the ribbon stage.  This incorporates a significant amount of air into the batter.  You didn't mention it, but I imagine the flour is then folded in.

The cake will work mechanically.

However, I cannot imagine it will taste very good:  there is no salt to enhance flavor, no fat (other than from the eggs), and no flavoring such as vanilla.  So the only significant flavor will be from the eggs themselves.  

As to how long it will keep, I imagine it would freeze well; it will probably keep at room temperature for 2-3 days.

Update: I see from the link added to the question that these layers are intended to be used in layer cake with other flavors and components, where its neutrality is actually a virtue.  I still think it needs about 1/2 tsp of salt, and maybe a touch of vanilla or even pistachio extract if you can get it, but the neutral flavor makes sense in context.