I have first hand knowledge of static fires. In August 1988 on a very hot dry afternoon after flying our Taylor Monoplane, we decided to refuel. We were based on a farm strip and always bought 4 star from the local petrol station filled our big plastic can ( actually a water can bought at a camping shop ).
We used a plastic funnel which sat into the tank on top of the cowling.
I had filled about 20 litres and was just coming to the end and having held the heavy can at shoulder height was just swilling the last bit out when there was a large click followed by flames that stated to melt the full funnel. lots of fuel poured down the fuselage and wing, which was alight, this caught the fabric on fire. I was holding a flaming can which Ii threw as far from the aircraft as possible, but it caught the grass on fire. The whole episode lasted several minutes as we did not have a fire extinguisher and had to beat out the fire with rags. We were stupid and complacent. After this we grounded the METAL funnel and METAL Fuel container to the METAL hangar door. An expensive lesson learnt.