Rotax fuel consumption?
Thread Starter
Joined: Oct 2003
Posts: 338
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From: Ireland
Rotax fuel consumption?
I'm currently researching the Ban-Bi, which has a Rotax 912/912S, in an effort to work out how much I'm going to pay for building/running it in total (I haven't bought it yet). In order to do that without breaking the bank, I'm creating an accurate sim model in X-Plane (I know it'll only be 95% accurate but that's enough for me if I get the Cd, shapes and airfoil right)
The thing is, it appears the Rotaxes (Rotaxii?) burn MORE fuel at higher altitude (in real life) for the same RPM, whether wobbly prop or not. How is this possible? I don't understand it. Does anyone have any experience with Rotax products? I know the V220T is coming out, and that's FADEC etc, but they'll never get a 220hp engine on the a/c so it's not relevant.
Any thoughts? I've searched the net but it's not giving me realistic SFC figures at altitude. I know it's a long shot, but someone might be able to help.
PS: How does the Ban-Bi (or any aircraft) get a relatively high roll rate with flaperons? The roll authority of the flaperons is only +3/-5 degrees!
The thing is, it appears the Rotaxes (Rotaxii?) burn MORE fuel at higher altitude (in real life) for the same RPM, whether wobbly prop or not. How is this possible? I don't understand it. Does anyone have any experience with Rotax products? I know the V220T is coming out, and that's FADEC etc, but they'll never get a 220hp engine on the a/c so it's not relevant.
Any thoughts? I've searched the net but it's not giving me realistic SFC figures at altitude. I know it's a long shot, but someone might be able to help.
PS: How does the Ban-Bi (or any aircraft) get a relatively high roll rate with flaperons? The roll authority of the flaperons is only +3/-5 degrees!
Joined: Jan 2003
Posts: 517
Likes: 37
From: Kelowna Wine Country
My 912S uses 18 litres/hour at 5,200 revs.
While it is interesting to know and gives a very rough guide to running costs I'm not sure why people get worked up over the exact consumption or fuel cost.
There was a thread on another site that asked whether the poster could use 87 Octane gas in an uprated 912.
Simple really. Even if you used 10 Gals /week average and bought the best gas as opposed to the cheapest the difference would be about $75 a year.
If that bothers you for Pete's sake get rid of the plane. Who wants to risk death for $75?
While it is interesting to know and gives a very rough guide to running costs I'm not sure why people get worked up over the exact consumption or fuel cost.
There was a thread on another site that asked whether the poster could use 87 Octane gas in an uprated 912.
Simple really. Even if you used 10 Gals /week average and bought the best gas as opposed to the cheapest the difference would be about $75 a year.
If that bothers you for Pete's sake get rid of the plane. Who wants to risk death for $75?
Joined: Apr 2003
Posts: 2,359
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From: Midlands
I am 95% of the way through building an MCR-01 Club. I assume you are going for the MCR-01 VLA not the MC100? All Ban-Bi’s so it gets confusing! I will PM you my contact details and you are welcome to give me a call; I have flown the VLA, Club and the ULM.
In real world use you will get about 18lph using Mogas. Avoid Avgas if possible as it is bad for the engine with increased oil changes etc to try to get read of the lead. I was running an AA5B with a fuel cost of £45 ish per hour, so £17 to go faster was a considerable inducement.
Rod1
In real world use you will get about 18lph using Mogas. Avoid Avgas if possible as it is bad for the engine with increased oil changes etc to try to get read of the lead. I was running an AA5B with a fuel cost of £45 ish per hour, so £17 to go faster was a considerable inducement.
Rod1
Joined: Apr 2003
Posts: 2,359
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From: Midlands
No Mogas at larger airports that I know of. But provided I keep Avgas use to a minimum, by using Mogas from home base etc I expect to avoid the worst of the problem. The engine is cleared to run on it, it just does not do it any good and with an endurance of 4.5 hours at 130Kn I can get a long way between refills.
When 100LL dies Mogas may become available at larger establishments, after all, most of the GA fleet can run on it and there is no other alternative without changing every Piper and Cessna engine for a JetA1 burner.
Rod1
When 100LL dies Mogas may become available at larger establishments, after all, most of the GA fleet can run on it and there is no other alternative without changing every Piper and Cessna engine for a JetA1 burner.
Rod1
Joined: Feb 2001
Aviation Qualifications: PPL
Posts: 1,222
Likes: 2
From: Worcestershire, UK
No probs for Rotax engines mixing 100LL and Mogas in any ratios EJ. But as Rod 1 mentioned earlier, the lead doesn't do the engines any favours if used excessively.
100LL is also
expensive too 
Rod, when do you expect to get your MCR flying?
100LL is also
expensive too Rod, when do you expect to get your MCR flying?
Joined: Apr 2003
Posts: 2,359
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From: Midlands
She is booked in to be painted in about 6 weeks. After that there will be a number of little jobs. My estimate is around Christmas for a finished aircraft, but then the paperwork will need to catch up and test flying needs happen. Because of the time of year it may be April before she comes out to play.
Rod1
Rod1
