Dear friend,
What's the highest altitude can Rotax912UL2 and Rotax914UL2 fly?
Thanks
What's the highest altitude can Rotax912UL2 and Rotax914UL2 fly?
Thanks
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Re: What's the highest can Rotax912UL&Rotax914UL fly?
by Roger Lee » 12 years ago
Hi Johnny,
That's kind of a tricky and sticky question. Some aircraft MFG's say up to 14.5K and that should be more than enough for people. I couldn't find it, but I think Rotax uses 16K. I have friends that have been well over 18K, but then you run into rules and regs to comply with depending on where you live. You also have to consider the carb jetting, prop, aircraft design and weight, operator oxygen supply, ect...
I guess it will go until it fails to climb any more.
Maybe Rob has some more specific info.
Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell
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Re: What's the highest can Rotax912UL&Rotax914UL fly?
by Johnny Chow » 12 years ago
Dear Roger，
Thanks for your reply.
I want to use Sinus912 by Pipistrel(Slovenija) to fly to 6000 meters altitude,the aircraft uses Rotax
912UL2 engine.
Can you give me some professional advise of the flight,especially the engine.As you know,if the aircraft climbs over about 3500 meters,the engine will be rich of gas,and lose some power.I'm afraid that the engine will be shut down automatically.
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Re: What's the highest can Rotax912UL&Rotax914UL fly?
by Roger Lee » 12 years ago
That particular aircraft can make that altitude and the prop and aircraft are setup to do it. You will loose approximately 3% of the engine performance for every 1000' over sea level and standard temp. You will loose approximately 55% of you engine performance, but it won't just quit and should make it just fine with that aircraft. IF I were to be a those high altitudes all the time and I took off from a fairly high elevation I would consider a carb jet change to a smaller size. Changing jet sizes should be done with some understanding and education. I hope you have some education and training for those high altitudes?
Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell
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Re: What's the highest can Rotax912UL&Rotax914UL fly?
by Mike Hoare » 12 years ago
Your danger here is not how high you can get but how fast you can get back down. The Sinus has a relatively low Vne which is flutter limited and must be compensated for temp and altitude or you will start losing components. I mention this because should you reach your max aerodynamic altitude and something should happen that requires you to get back to the ground fast (think about airframe icing, oxygen system malfunction, engine fire, illness, hypothermia) you will be stuck up high for a long time even with your spoilers deployed. I know whereof I speak unfortunately having had the controls on a Sinus lock up at high altitude due ice formation under the gap seals...
An emergency descent will also hyper cool your engine to the point that when you need it at lower altitudes it might not be available. Been there done all the stoopid things.
In closing I would suggest you wear a parachute if you intend to probe the flight envelope.
Good luck, Mike.
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Re: What's the highest can Rotax912UL&Rotax914UL fly?
by Roger Lee » 12 years ago
I'm with Mike on this. The military has flown the 914 much higher, but they are drones. You face a whole different set of issues at the high altitudes.
Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-349-7056 Cell
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