912is Fuel Consumption

Rotax-Owner wrote:

The 912 iSc/iS engine has two different modes, the POWER and ECO mode which differ significantly in fuel consumption. The switchover between ECO and RICH mode is about 97 % of the throttle position.

We suspect you were operating mostly in power mode and it skewed the data slightly?

AV-Gas does not burn as sufficient as auto fuel, but it does have excellent anti-knock abilities and is very stable fuel that can be stored for long periods of time. Our recommendation is if you are going to continue with Av-gas more then 30% of the time, is to follow the maintenance instructions set out in the Rotax maintenance manual as the intervals change. We also recommend running a fuel additive of TCP or Declan to help scavenge the lead build-up. TCP and Declan does amazing things and does an excellent job of getting rid of that lead!

I appreciate the reply. We have some settings in place for our orbiting flight regime that keeps the throttle at a pretty low setting but I will be verfying that with our chief pilot. We follow all aspects of the maintenance manual for preventative maintenance, we are in the business of keeping these things flying for continuous coverage! I do know we will be doing some testing in regards to the difference in fuel types so we can better predict our flight times. 

Kristof HUCHET wrote:

Hello,

Just a question why do you use  100LL instead of 91? This is a very bad idea, first because this engine is build to use MOGAS or similar without lead, it's able to use 100LL but as you have see with a poor yeld, so more cosumption and less power (dificult to feel) an other problem if you use 100LL is that you must reduce the time between maintenance (/2) for oilchange but for any other things like gear box revision that come at 500h instead of 1000...

For the EGT don't look at them because you don't have any possible adjustment for mixture, it's only for the first adjusting when the engine is installed for the first flight and if you change of leaving altitude (from sea side to montain) not for a trip, for that the calculator do it by himself.

Good flight

We looked at the EGT as the difference in BTU output was noticable via EGTs. I realize the computer doesnt use it for fuel trim but its helpful to use to see what is going on comparatively. We use 100LL as that fuel is more readily available at some remote locations we will be flying our drone from. 

姓, xìng wang wrote:

Can we use 91 on Rotax914F2?

As last week I loose a engine after 180hrs due to 100LL used.one cylinder got damaged and engine will go for major overhaul.

This is what you call "hijacking someones post"

Looking expert opening. But still no response ??

姓, xìng wang wrote:

Looking expert opening. But still no response ??

The rotax manual for the 912iS states what fuel can be used for that engine, does the manual pertaining to yours specify the fuel for that engine?