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Adam

Rotax 912iS versus the 914 Turbo - Which One?

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Happy New Year Everyone!

Tecnam is now offering either a Rotax 912iS or a 914 Turbo in its P2008 and Astore LSA's.   It got me thinking -  The 912iS is Fuel Injected, the 914 is turbocharged but is back to dual carbs.  Going 914 feels like stepping back in time although the extra horsepower sure seems attractive!   Toying with the idea of adding a second aircraft to my stable.  I have always been drawn to the fit and finish of Tecnam.  Having said that I chose FD 3 times in a row for some particular reason! 

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Nice looking airplane.  I would stick with the 912i.  In a light sport it does all the work necessary at whatever altitude airport and density altitude operations plus it starts really easy, get's great fuel mileage for those long trips and has no instances of "rubber in the carbs".

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I would prefer the 914 if I was you.  It can do what the 912 can't and you could really use it because you are surrounded by mountains.  

The 914's performance only gets better and better up high and the 912 falls off normally.  At altitudes needed for California cruising there's a 20kt difference.  Climbs to 12,000 will have a night and day difference as well.

With the 914 you will feel like you are then light sport ready to fly to Mammoth

With the 914 my CT would be 150+ kts top speed.  With the 912i my CT would be 127+ kts top speed.   Best speed for the 912i is at 7,500'DA  Best speed for the 914 is prolly 16,000'.

 

 

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3 hours ago, paul m said:

Maybe the 915iS will be an option at some point unless its too heavy.  

That would be sweet!  Best of both worlds, fuel injected and turbo!

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20 minutes ago, FlyingMonkey said:

912iS.  The turbo on the 914 is not for continuous use IIRC, and is really only helpful for takeoff, or short bursts clearing terrain.

My best friend has one in his Europa.  We use continuously and can cruise near 200mph.

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37 minutes ago, FlyingMonkey said:

912iS.  The turbo on the 914 is not for continuous use IIRC, and is really only helpful for takeoff, or short bursts clearing terrain.

It is true that the 115 hp is available for five mins. but 100 hp continuous. When you get up a bit higher your 100 hp non turbo will be making probably about 60 hp but the turbo is still making sea level hp up to about 16000, after that it drops off a little. 

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26 minutes ago, ct9000 said:

It is true that the 115 hp is available for five mins. but 100 hp continuous. When you get up a bit higher your 100 hp non turbo will be making probably about 60 hp but the turbo is still making sea level hp up to about 16000, after that it drops off a little. 

Think about it, it means a ~60% cruise power increase!  

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Hi, Mark Gregor from Advanced Aircraft/Tecnam US here.

I hope you don't mind me responding but the post is referencing a Tecnam after all!

We end up discussing pros and cons of the Rotax engines regularly. All three Rotax engines are offered by Tecnam because we believe they are all good viable choices. It just depends on what you want. The 912ULS is a well proven engine at a low price. The 912is is the latest in technology, full fadec w automatic lean of peak operation below 97% power. Impressive but no more horsepower than the ULS and likely less in many conditions. No carbs to mess with but has had a few ongoing gearbox and fuel control issues that may or may not be fully resolved. Definitely much better than when it was first released though. 

The 914 is a mature design but the turbo can be additional maintenance if a few basic care rules are not followed. The last 914s we delivered had carb leaks at high manifold pressure settings. Was easily resolved by a good Tech but goes to show nothing is ever perfect. With that said and nearly 1500 hours divided between all three Rotax engines the 914 is nearly always my first choice to pull out of the hangar. I like the 914 because it is smoother, quieter and substantially more powerful! The first time I flew the P2008 with the 914 i was very surprised how much stronger it was. Really sets you back in the seat compared to the 912. Takeoff roll is substantially reduced. The 914 cruises at 35 inches manifold continuous. At this setting the 914 is making a lot more horsepower that a 912. 40 inches manifold or 115% power as Rotax calls it is limited to 5 minutes. When I hear negativity about the 914 it is nearly always from someone who has never flown behind one.

Disadvantages?  A $20,000 more than the ULS and $8,000 more than the 912is!

Mark Gregor

Gregorma@bevcomm.net

507-3279465

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4 minutes ago, markmn said:

Hi, Mark Gregor from Advanced Aircraft/Tecnam US here.

I hope you don't mind me responding but the post is referencing a Tecnam after all!

We end up discussing pros and cons of the Rotax engines regularly. All three Rotax engines are offered by Tecnam because we believe they are all good viable choices. It just depends on what you want. The 912ULS is a well proven engine at a low price. The 912is is the latest in technology, full fadec w automatic lean of peak operation below 97% power. Impressive but no more horsepower than the ULS and likely less in many conditions. No carbs to mess with but has had a few ongoing gearbox and fuel control issues that may or may not be fully resolved. Definitely much better than when it was first released though. 

The 914 is a mature design but the turbo can be additional maintenance if a few basic care rules are not followed. The last 914s we delivered had carb leaks at high manifold pressure settings. Was easily resolved by a good Tech but goes to show nothing is ever perfect. With that said and nearly 1500 hours divided between all three Rotax engines the 914 is nearly always my first choice to pull out of the hangar. I like the 914 because it is smoother, quieter and substantially more powerful! The first time I flew the P2008 with the 914 i was very surprised how much stronger it was. Really sets you back in the seat compared to the 912. Takeoff roll is substantially reduced. The 914 cruises at 35 inches manifold continuous. At this setting the 914 is making a lot more horsepower that a 912. 40 inches manifold or 115% power as Rotax calls it is limited to 5 minutes. When I hear negativity about the 914 it is nearly always from someone who has never flown behind one.

Disadvantages?  A $20,000 more than the ULS and $8,000 more than the 912is!

Mark Gregor

Gregorma@bevcomm.net

507-3279465

That smooth power is such an upgrade that it becomes a different class of airplane, especially out west where that power is needed and useful for high percentage of flights.  Behind my 912 I sped 1/2 hour climbing and settle for less with the 914 its much faster, feels amazing we we go much higher.

Have had carb issues for sure.

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Yes there will likely be some carb maintenance on the 912ULS and the 914 but overall we have seen less issues than on the 912is.  The 912is is the first full fadec aviation engine with auto lean of peak and it has been a challenge. I have full confidence Rotax will get it 100% but as of today I'm still more comfortable behind the carb engines. 

Mark

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2 hours ago, ct9000 said:

It is true that the 115 hp is available for five mins. but 100 hp continuous. When you get up a bit higher your 100 hp non turbo will be making probably about 60 hp but the turbo is still making sea level hp up to about 16000, after that it drops off a little. 

Got it, thanks for clarifying.  Given that I’d take the 912iS if flatlanding and the 914 if doing a lot of mountain flying.

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4 minutes ago, FlyingMonkey said:

Got it, thanks for clarifying.  Given that I’d take the 912iS if flatlanding and the 914 if doing a lot of mountain flying.

Also as has been mentioned the 914 is quieter and very smooth. I believe this is because of the slightly lower compression ratio but I could be wrong on that.

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So perhaps the right answer is to add 2 more planes to my stable?  An Astore with 912iS and a P2008 with the 914 :-)

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1 hour ago, markmn said:

Yes there will likely be some carb maintenance on the 912ULS and the 914 but overall we have seen less issues than on the 912is.  The 912is is the first full fadec aviation engine with auto lean of peak and it has been a challenge. I have full confidence Rotax will get it 100% but as of today I'm still more comfortable behind the carb engines. 

Mark

Mark - while I have you on the horn...  Talk to me about the Astore v p2008.  Which is your favorite (and why)?

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Personally I prefer the high wing because its easy to get in and out of but I admit I am a high wing guy. The Astore is not hard to get in and out of but just not as easy as the 2008. The 2008 is a bit longer and larger than the Astore and thus handles turbulence and cross wind landings a bit better. Overall both the Astore and P2008 are just physically larger than other LSAs so there is not a lot of difference.

Although we occasionally see a pilot switch from high to low wing or vise versa it doesn't happen often. Both the P2008 and the Astore are great planes just like the Flight Design and because I like one better doesn't mean others will. I recommend getting a test flight in every aircraft you can!

Mark

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I prefer a supercharger over a turbocharger anyday . Turbo exhaust failure makes for a great blow torch. I have seen some scary holes burned through fancy tight cowls. In my opinion as an engineer the supercharger is safer and for that reason even with the parasitic power draw. We have been conned into the cheap bolt on turbo extra power. Just my 5cents worth.

 

Keep the greasy side down

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1 hour ago, Odowneyeng said:

I prefer a supercharger over a turbocharger anyday . Turbo exhaust failure makes for a great blow torch. I have seen some scary holes burned through fancy tight cowls. In my opinion as an engineer the supercharger is safer and for that reason even with the parasitic power draw. We have been conned into the cheap bolt on turbo extra power. Just my 5cents worth.

 

Keep the greasy side down

Your need to keep the greasy side down may be 'cause you pushed the pistons into the sump with over boost at low engine speed.

 

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