Only one thing to say to this: RTFM !
Care to cite the relevant F section of the FM?
I don’t like touch propellers.
In principle you are right of course, but the speed at which you do this makes it extremely unlikely that the engine comes to life especially if you follow the above described procedure of gently pushing against TDC and hold it there for a bit. If anyone has heard of an accident, please chime in, always prepared to learn..
An alternative is to do the burping and oil check after the flight. Then it becomes a matter of a few turns only, even with installations that have the oil reservoir high up. A further advantage is that the oil qty measurement becomes more exact. FWIW, because indeed the oil consumption is so low that you never need to ‘plan’ in case of a long flight. I keep track of it: 0,02 liters/hr (max allowed 0.06).
johnh wrote:
Care to cite the relevant F section of the FM?
Page 4-5 in Rotax 912 Operators Manual
Page 4-5 in Rotax 912 Operators Manual
Don’t have one – my Rotax experience was in a far off time in a far away place (well, Dax, in 2021). What does it say?
Only one thing to say to this: RTFM !
So full circle really. It tells you to do what I used to do – and might again if I fly another Rotax. It contains mysterious words about maintaining compression but it doesn’t specifically say to hold the prop at the point of maximum compression. Shame, because that was a good hint. I’m surprised the instructors I was flying with hadn’t heard about that.
FWIW the Tecnam P2006T POH offers ‘alternatively idle engines one minute’ in lieu of the manual burping. Engines are Rotax 912s.
Bathman wrote:
Why bother the average Rotax uses an egg cup of oil every 50 hour check.
Maybe when it’s new.
FWIW the Tecnam P2006T POH offers ‘alternatively idle engines one minute’ in lieu of the manual burping. Engines are Rotax 912s.
Can you safely start a Rotax 912 without clearing the crankcase of accumulated oil after an extended shutdown? I’ve flown them a bit but never dug into this.
If you start most other dry sump engines in this condition oil tends to be expelled rapidly out of the crankcase breather and damage can occur. On those engines It’s not just about checking the oil tank level. Anti-drain-back valves are used sometimes between the engine and oil tank, but if they fail (or in the case of a manual valve, if you forget to open the valve) your engine is toast.
Perhaps that situation is prevented by the open return flow path between sump and tank (no positive displacement scavenge pump, as Steve6443 describes) but without specific knowledge I’d not be attracted to starting a dry-sump engine with oil accumulation in the crank case.
Thanks
Clipperstorch wrote:
Maybe when it’s new.
I’ve flown behind examples with over 5000 hours on them and they still use next to no oil.
