Ragz

I ran my p120 after almost 2-3 months. The engine started instantly and stabilized normally. I did one full power run and maintained idle for about a minute or so. After running (on the ground) for about 2 minutes, it flamed out suddenly. This is the first time this has happened in 3.5 hrs of run time. The hand held GSU unit had "low RPM" written on it. The user manual says this means low rpm or flame out.

What does this mean? The plane has been in its wooden case with fuel tanks full including UAT for about 2-3 months. Could it have something to do with the fuel delivery system? or old fuel??? Thankfully I was still on the ground and had not taken off....

lov2flyrc

My Feedback: (24)

Ragz...... What was the temps outside?

Ragz

Todd, the temp should be about 30C.

I should have mentioned, that the flame out was followed with a white smoke and the engine went into auto shut down sequence. I restarted the engine after a few minutes, and everything was normal this time. I did not fly, just ran the engine for abt 5 mins. I dont think i can fly until I nail down the reason for the "low rpm" shut down.

DavidR

My Feedback: (1)

Ragz,

It could just be an air bubble, if you ran it for a few minutes afterwards with no problems you are probably good to go.

lov2flyrc

My Feedback: (24)

Ragz,

I was having the same issue with my P-120 during HOT days (above 90F), it would flame out during throttle-up for takeoff. There was a minor problem with the combustion chamber that was causing the flamouts but only on hot days and always just after a Taxi. As David said, it could have been a bubble but just be aware you might be experiencing the same problem.
Todd

cairoman

Yup,

Sounds like it has been an air bubble. You can still fly the Roo. Even if the engine flames out, landing the Roo without power is even easier.

Rgds,
Chris

Ragz

Ha ha Chris, one particular friend of mine in India wouldnt agree to your statement about flying the roo dead stick. His engine flamed out for some strange reason (failsafe they say now) and his roo could not make it back. It died.

Todd, was the problem only in your engine? Or is it in all p120's? How can it be fixed?

lov2flyrc

My Feedback: (24)

just my motor.... Not a engine wide problem. Was very easily fixed and was done under warranty however it did need to be sent in. Had the engine back in a week.

Jet Doctor

Hi Ragz

Air bubble is the "deadly enemy" of any turbine as it immediately kills the flame in the chamber. The white smoke you saw afterward is the pump still pumping fuel into the chamber-unburnt fuel. The controller will then either shut down on low EGT or low RPM depending on which one it sees first. Do a good few ground runs shaking the plane a bit and see if you can get it to cut. I don't know the Jetcat controller so I am using a very generalised approach. Your next question would be "but I have a UAT". Yes, but there is a length of tubing to the pump and the pump as well where an air bubble can "hide". Some controllers have a prime pump function that you could use to clear these bubbles but then you are in for a wet start, for sure! Check and recheck the tubing between the UAT, the pump and the turbine. If you don't find anything, it should be OK.

Good luck

Zane

Ragz

Copy that todd....

cairoman

Ha ha Chris, one particular friend of mine in India wouldnt agree to your statement about flying the roo dead stick. His engine flamed out for some strange reason (failsafe they say now) and his roo could not make it back. It died.

Not mine though mate,

If your weight does not exceed 7,5 Kg's you have a fantastic glider. I have heard of some guys in Germany, who actually are flying Roo's as slope soarers!!!!!

Chris

dbarrym

My Feedback: (47)

As mentioned, sounds like an air bubble. I had this happen on a touch and go with my Hot Spot at this year's BITW (first flight on Thursday, naturally) at the worst possible moment - in a tight, high AOA departure turn. Result - one squished Hot Spot. They don't glide well with full tanks at minimum airspeed!

The plane (including fuel system and UAT) had more than 65 trouble-free flights in the preceeding 3 months, so I was baffled. I eventually traced the problem to leaky Festo's on the suction side of the fuel system; the fuel lines were old (2 years?) and no longer pliable enough to make a good seal.

I have also had a couple Festo fitting O-ring seals go bad (in the small mm size) and not seal well, and they are too expensive to consider as a regular preventative maintenence replacement item. Two gear-up landings and one flameout were enough for me - I no longer use Festo's anywhere and safety-wire all fuel line (and air) connections.

Working on the fuel and air systems are more of a pain now but the tradeoff (no more flameouts!) is worth it.

Barry