Outboard fuel tanks
The original KR-2 system has one header tank, we changed this in 2 outboard leadingedge fueltanks and one centertank. So there is a minor centergravety shift. All the parts are made of 2024T3, the ribs I made in O condition and were put afterwards for 30 min in an oven so they be now in T6 condition.
The tank is tested with 2 bar. This is a lot but it is the rule in the Netherlands.
The outboard tanks feeds the centertank by gravety and the center tank feed the engine via an booster pump. Between the center an outboard tanks we put an one way flapper valve.
Above, RH fuel tank. The inboard frame has the same angle as the fuselage so we can put more fuel in. The round prop is the connection between the outboard an the centertank. On this prop is coming the flappervalve.
Inboard rib has an extra doubler to prevent cracking. Riveting everything wet.
Before closing the tank we sealed the ribs.
Realy hard to rivet the aft spar but we made it.
Quick test to see if there are air bubbles, after 24 hours the pressure was still the same.
Our garage is really small so we had to go outside to aline the tanks on to the wings.
We decided to make filters between the outboard and inboard fuel tank.
On the other side of the filter is the flapper valve.
This panel will close the tank and also support the tank, because it is connected just behind the fwd spar. A strap between the fwd and aft spar is connected to this panel and hold the torsion forces.
The fuel sender is connected to the panel.
Now the outboard tanks are finished we can start with the center fueltank
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