Upgrading Rotax 912UL (80HP) to Rotax 914UL (115HP), experience anyone?
Join Date: Sep 2003
Location: Retford, UK
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Yesterday I got feedback from a local friend of mine though that the overall consumption of a 914 at the club is 33% more than the 912ULS, but flying faster; the difference is realistically 28%, approximately…………
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Location: Ecuador
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Folks,
for those who are interested:
After running the numbers and the characteristics of both engines (as discussed on here) through my head a few dozen times, and after talking to the appropriate people; I finally have decided to go for the 115HP 914 Turbo conversion kit. (ORIGINAL Rotax Turbo & computer).
I will keep my 80HP Rotax 912 engine which hasn´t suffered any incidents yet, and which seem to run fine! No excessive oil consumption, nothing.
Let´s hope that kit gives me the same performance as it does to the other 914 owners.
True!! Very true!!
But the killer argument for me was that where we are; we do actually fly ridiculously high at times. There´s airports at 3.000 meters here, and a few other "obstacles" that go over 6000 meters:
And although the Rotax turbo is not designed to maintain the exact 115HP at these altitudes, it will make a difference compared to the conventionally breathing engine!
Okay, after some more research it turns out that the Turbo´s of the Lycoming´s / Continental´s are primarily there to give you your 100% power at higher altitudes. Correct?
Rotax´s Turbo however makes concessions; it both gives you more power at higher altitude (albeit less than 100%) and it adds a lot of grunt at lower level--> making the handling more "sexy" in the lowlands--> which is where I´m based. The Rotax turbo "works" at any time……….which explains the 25% more consumption, or somewhere around there.
I guess for a lot of UK / US guys on here, the 100HP 912ULS is just fine.
But flying here, I think I pay the extra fuel burn penalty, but enjoy the sexy handling at the beach and more importantly: the extra power when I "hit" the Andes.
Cheers,
###Ultra Long Hauler###
for those who are interested:
After running the numbers and the characteristics of both engines (as discussed on here) through my head a few dozen times, and after talking to the appropriate people; I finally have decided to go for the 115HP 914 Turbo conversion kit. (ORIGINAL Rotax Turbo & computer).
I will keep my 80HP Rotax 912 engine which hasn´t suffered any incidents yet, and which seem to run fine! No excessive oil consumption, nothing.
Let´s hope that kit gives me the same performance as it does to the other 914 owners.
True!! Very true!!
But the killer argument for me was that where we are; we do actually fly ridiculously high at times. There´s airports at 3.000 meters here, and a few other "obstacles" that go over 6000 meters:
And although the Rotax turbo is not designed to maintain the exact 115HP at these altitudes, it will make a difference compared to the conventionally breathing engine!
Rotax´s Turbo however makes concessions; it both gives you more power at higher altitude (albeit less than 100%) and it adds a lot of grunt at lower level--> making the handling more "sexy" in the lowlands--> which is where I´m based. The Rotax turbo "works" at any time……….which explains the 25% more consumption, or somewhere around there.
I guess for a lot of UK / US guys on here, the 100HP 912ULS is just fine.
But flying here, I think I pay the extra fuel burn penalty, but enjoy the sexy handling at the beach and more importantly: the extra power when I "hit" the Andes.
Cheers,
###Ultra Long Hauler###
Join Date: Sep 2010
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Rotax 80hp high fuel use
Hi Folks,
while we,re out there with Rotax,s my 80 hp 912 has started to use a lot more fuel, used to burn approx 12 to 14 lph at 4600 rpm and after careful check its using 18lph . Have checked the chock is full off after starting also checked idle needle setting, carbie diaphragms ete, and of course no leaks any ideas ?
Cheers
while we,re out there with Rotax,s my 80 hp 912 has started to use a lot more fuel, used to burn approx 12 to 14 lph at 4600 rpm and after careful check its using 18lph . Have checked the chock is full off after starting also checked idle needle setting, carbie diaphragms ete, and of course no leaks any ideas ?
Cheers
Join Date: Sep 2010
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914,s
Hi Again,
Re the 914 turbo,s I have just delivered four new aircraft to Outback stations here in Oz they all ran well and at 5000 rpm at say 4000/5000 ft and between 25/ 30 deg OAT theY all returned approx 18 lph
Would post a pic but don't know how to do that one my iPad
I,m an old 18000hrs steam driven jock!
Re the 914 turbo,s I have just delivered four new aircraft to Outback stations here in Oz they all ran well and at 5000 rpm at say 4000/5000 ft and between 25/ 30 deg OAT theY all returned approx 18 lph
Would post a pic but don't know how to do that one my iPad
I,m an old 18000hrs steam driven jock!
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Please bear the following in mind....I AM NOT AN AVIATOR.
ISTR Rotax engines having a "needle and slide" (Bing?) type carburettor.
Wear in the slide/body can cause air -leaks and allow the needle to fret on the jet...needle -flutter causes uneven mixture, which would probably mean a wider throttle-opening for the same power-output.....(if you've got good CHT monitoring and lean-out, , that eliminates that suggestion.
The english SU carb. attempted to meet emissions legislation by having a main-jet mounted on a bimetal strip, (fuel-temp compensation)combined with a wax-capsule at the jet-base ( ambient air compensation) and a needle spring- biased against the jet (eliminating flutter) Of course, it worked fine for a short while , until the needle sawed the jet-orifice oval and a corresponding wear-mark down it's length.....fuel consumption increased dramatically.
the giveaway, was an extremely rich tickover, with virtually normal full throttle AND LOAD operation. or, if you weakened the idle mix to a satisfactory state, thething would starve and fluff or die as you opened the throttle. new needle and jet was a cure.....similar situation with AMAL motorbike carbs.
HTH.
ISTR Rotax engines having a "needle and slide" (Bing?) type carburettor.
Wear in the slide/body can cause air -leaks and allow the needle to fret on the jet...needle -flutter causes uneven mixture, which would probably mean a wider throttle-opening for the same power-output.....(if you've got good CHT monitoring and lean-out, , that eliminates that suggestion.
The english SU carb. attempted to meet emissions legislation by having a main-jet mounted on a bimetal strip, (fuel-temp compensation)combined with a wax-capsule at the jet-base ( ambient air compensation) and a needle spring- biased against the jet (eliminating flutter) Of course, it worked fine for a short while , until the needle sawed the jet-orifice oval and a corresponding wear-mark down it's length.....fuel consumption increased dramatically.
the giveaway, was an extremely rich tickover, with virtually normal full throttle AND LOAD operation. or, if you weakened the idle mix to a satisfactory state, thething would starve and fluff or die as you opened the throttle. new needle and jet was a cure.....similar situation with AMAL motorbike carbs.
HTH.
