Oil level check

Okay, I understand whole burping process is in the cost of using a 912. What I still don’t know is if the burping process is just for checking oil level, OR, is it also to ensure no oil in cylinders and prevent engine damage ? As some posts state ?

thanks

just for checking oil level......

FYI we have a guy on the field who owns 7 Rotax powered aircraft. Has been flying for 30 years has never burped a Rotax.....and never had an issue !!

Bill, isn't it actually every 72°?

912ULS Gear Box = 51 teeth against 21 teeth;  51/21 = 2.4285 ...  Crankshaft/Prop Revs

360/2.4285 = 148.235  Degrees of Prop Rev per Crank Rev.

148.235 / 2 compressions per revolution = 74.118 Prop Degrees per Compression.

Roughy 5 (Not 5.000) compressions per revolution.  Close enough for most practical Purposes.

Actually 4.857 Compressions per prop revolution,  or 5 compressions per 370.6° if you want to get nitpicky.

Are you really going to notice that extra 10° when just hand cranking?

- - -

The decimals are messy and Non-Terminating because the Gear Teeth Ratios are Co-Prime numbers. (51:21) = 51 : 7x3;  GCD = 1, Ideal!

The Prop, Crank and Gear Teeth will come back into exact sync every 21 Prop revs, during which time  every tooth on one gear will have met every tooth on the other gear causing any minor machining imperfections to be evenly worn OFF, instead of being worn IN.

The 912A, F and UL with the 2.27 (50/22) Gears re-sync every 11 prop revs with half the teeth meeting only half the other teeth.

50:22 =  5x5x2 : 11x2;  GCD = 2

Workable but not perfectly ideal.  

I knew it was a simple answer.  ;)

Very cool stuff, though.