I originally flew this Sbach (just before the coronavirus lockdown) with an NGH 17cc petrol engine but on the 2nd flight the engine broke (crankshaft or conrod – I’m not sure which yet as I’ve not dismantled it). To replace it I bought an OS GT15 (petrol with spark ignition) as the engine dimensions match those of the NGH engine.
Installation of the engine was not a problem but there was a twist, this OS engine is a 2nd generation and the external fuel pump is no longer mounted on the crankcase but has to go either on the firewall or inside the fuselage. Apparently the pulses from the crankcase are hot which affects the operation of the pump!
The OS engine is shorter than the NGH so I was able to fit the cowling (not used on the maiden flight) although installing the giant OS muffler was interesting.
Another interesting feature of the OS engine is that, according to their docs, its carby does not have a low speed needle valve. Instead they have a mixture adjustment and a high speed needle valve. Apparently you are not supposed to adjust the mixture until engine run-in has been completed and then only if absolutely necessary.
I’m now looking at resuscitating my Phoenix MXS which hasn’t flown for 3-4 years after landing gear and fuselage damage following a heavy landing in the farmers field when the (completely not missed Evolution 10cc petrol) engine conked out just after take-off. So back to the shed …
Nice looking model
That’s a nice looking plane Neil. Hopefully sometime this year you’ll get fly it….!