Engine cutting out over 16-17k

[Archaic]

Supercharger kicks in around 15k. I assume this is a mixture problem and I'm not rich enough?

 

I didn't see anything in the manual though about mixture control. Or, perhaps I'm misidentifying the problem?

[LURKINGBADGER]

there is a Fuelpumpswitch under the Elevatortrim wheel.

 

[Archaic]

I'm not understanding why this needs to be used above 15k, but not under it..

 

The supercharger compresses air to compensate for thinner air at altitude to maintain the correct fuel:air ratio, right? I don't understand why an additional need for the pump.

[LURKINGBADGER]

The sealevel atmospheric pressure is aprox. @ 1 Bar .

At 16000 feet the pressure is @ 0.5 bar ish.

It could be that the fuel starts boiling. And also turn on the fueltank pressurize switch (under the fuelgauge), which prevents boiling.

[VH-Rock]

Try turning on the fuel tank pressure switch, lower right hand side of the instrument panel :)

[Yo-Yo]

I'm not understanding why this needs to be used above 15k, but not under it..

 

The supercharger compresses air to compensate for thinner air at altitude to maintain the correct fuel:air ratio, right? I don't understand why an additional need for the pump.

 

The engine pump sucks fuel from the tank. Fuel lines resistance, relative height of the pump and the fuel inlet in the tank - they all create low pressure zone inside the tubes. Under this conditions as the atmospheric pressure gets lower the fuel can boil and make a vapour lock in the tubes.

[Archaic]

Great answers, thanks.

 

So you need both activated around 15k. Why not turn it on during the startup, or would that over pressurize the fuel tank?

[Art-J]

Do we need to touch the switch on the left at all? Following recommendations, I flip the right one (on the panel) only and it seems to be enough (mind You, I still haven't investigated the relevant part of the manual).

 

Edit - OK, after a test flight I noticed that the fuel pump switch (left) is more useful than tank pressure switch (right). Having only the right one on allows to climb high, but any sudden manoeuvre's with yaw will cause pressure drop and engine cutoff. Having left one only turned on seems to be good for everything up high. Which brings the question - in that case, what's the right one useful for anyway? :D

Edited December 19, 2016 by Art-J