And a next step has been done.
Due to icing up of the gastank due to fuel consumption (vapour is taken from the tank, which causes the tank to cool down and lose pressure) I initially installed electric tank heating, 5 Watt electric, thermostatic controlled. This was a fairly large current draw for the RX battery, but battery still could run the system for more than 1,5 hr like this. No biggie, but hey, what fun is there if nothing left to improve, right?
So yesterday I converted the fuel systm to "liquid feed", which basically comes down to fitting a riser tube in the tank so the fuel is delivered in liquid form instead of vapour. This means that there is no more evaporation in the fuel tank, therefore no temperature and pressure drop. Fuel pressure remains constant throughout the entire fuel duration.

But the fuel still needs to be evaporated because the burner cannot handle straight liquid (no burner of this type can).
To achieve that, the fuel line is coiled around the smokestack, the resulting vapour is then passed on to the gas control valve, and from there to the burner.
The much higher pressure required a readjustment of the regulating valve.

Start up procedure has changed a bit, in that with cold system, the evaporator needs to be preheated for about 20 seconds with a hand held miniature burner, and or safety reasons, after ignition this heating should be done for maybe 20 seconds more until there is some temperature in the smokestack. From there on, the system sustains itself.
Stability of pressure control has improved, the max output of the burner has increased, no shoocking differences, but another improvement nevertheless.
The most important improvement however is the reduction in electrical load, extending operating time by a factor of almost 3.

https://www.modelbouwforum.nl/attach...-1-jpg.599427/