Primarily for general aviation discussion, but other aviation topics are also welcome.
#1704537
rogerb wrote:Let me first say I do burp a cold engine, however:
The thought of prop turning without chocks or someone at the controls does not sit well with me.
The intro of the 912 brings forth several issues when viewed from those who are more used to "most/all?" Other aeroengines.
PS I have seen overfilling of rotax oil due to lack of burping.
PPS I also like to compression check these other engines and leave the prop just off compression to ease starting loads. I imagine this could start another topic


It is possible to hand prop a 912 but because of the Gearbox reduction and the minimum 200rpm you need to get the electronic module to fire it’s highly unlikely at burping speed,
You are only slowly turning the prop after all, but I always on a 914 switch off fuel pumps as part of my cooling down until the engine falters then switch off the mags, So next time burping there is no fuel in the carbs,
#1704574
The manufacturer recommends pre-flight checks of coolant and oil levels. These checks are independent of the starting procedure, as is made clear in the manual by the use of different numbered headings for Pre-flight checks and Engine start.

There is also no need to have electronic module switches independent of the starter switch, so that the engine can be turned on the starter with the 'mags' off. Many LSA are fitted with the ACS (Off, L, R, Start) switch.
#1704592
In the Eurostar:
  1. Remove oil tank cap, lift dip stick and prop it in the open mouth of the tank (saves wiping the stick clean).
  2. Pull through the prop, holding the pressure at the compression points for a few seconds until you can hear air gurgling in the tank.
  3. Insert the dip stick, wait a couple of seconds, withdraw it and measure the oil level.
  4. Top-up if necessary.
  5. Refit dip stick and tank cap.
  6. Master ON.
  7. Ignitions ON.
  8. Throttle FULLY CLOSED.
  9. Choke FULL (if cold).
  10. Starter ENGAGED.
  11. Engine normally starts within 2 seconds.
  12. Starter DISENGAGED.
  13. Check oil pressure (rises to 4 bar almost immediately).
  14. Check starter warning OFF.

Complete checks and go flying.

In the Eurostar the tank is at a height where only a relatively small amount of the oil remains in the crankcase and there is no chance of drawing in air if the oil level is within normal limits. There will be oil on the bearing surfaces and oil in the valve lifters so the engine can be started immediately and the oil pump will do the rest.

I have heard about cranking until the oil pressure comes up before switching on the ignitions. To me this loads the battery and heats up the starter unnecessarily. That said, I doubt that it does any harm.
G-JWTP liked this
#1704600
MikeW wrote:Not to mention the price:sophistication balance.

The thought that gets me is the fact I could buy a decent new car for the cost of a new Rotax. :twisted:

ivor.phillips wrote:...I always on a 914 switch off fuel pumps as part of my cooling down until the engine falters then switch off the mags, So next time burping there is no fuel in the carbs,

Interesting, Ivor. I'm sure mine won't start unless the pumps are on and tap open, even with the carbs full. Have you tried? I must take note next time. Thinking it through it should. More likely to be my memory at fault.:thumleft:
#1704617
Look at the price of a brand-new automotive engine, you'll probably have change out of £6K with no core to put in, an exchange rebuilt unit about 1/3 of that. The Rotax is possibly priced so high to cover liability insurance (and a ginormous profit-margin. Lycosaurus sat on their joint monopoly for years and now Rotax is snapping at their heels.....the fat profits finance the next stage of development and so their market-share grows.
the uncertified version is/was a tiny bit cheaper than the certified one...total ripoff.

Wait till the Chinese latch on and produce a Lycosaurus clone for less than 10K and they'll laugh all the way to the bank. When liability claims got silly, Piper and Cessna declared bankruptcy......liability ceased. same "could" apply to an engine manufacturer. there really isn't a sound moral or ethical reason I can see for these obscene charges......and, please, don't come the old saw about small volumes. Once a machine is working at full capacity, it's at maximum efficiency......got a huge waiting-list?- add another machine, add another wedge of profit. Design and tooling costs amortise in 10 years or less. If an old design is still selling, they'll keep making it and take an increasing margin...Rotax seem to have ploughed these profits into developing bigger, better and far more profitable engines and have thus bought an ever-increasing market-share.
#1704626
The Chinese are apparently already producing a Rotax clone.

https://scontent-lht6-1.xx.fbcdn.net/v/ ... e=5DB286B1

(Maybe it's just the valve covers. I was in Moscow many years ago at an exhibition where the new Soviet designed and built Zhiguli car was announced - actually the obsolete Fiat 124 for which they had bought all the machinery - and on the display model you could see where "Pirelli" had been buffed off the tyres and a Russian name applied with a branding iron :lol: Presentation is everything.)

The real threat will be when the Great Leader in N Korea personally directs the production of a new design that just happens to look similar!