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Fuel Injection or Carbs on my next CT?


Scrapman1959

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12 hours ago, DocRon said:

. . . " The biggest headache was getting the screens unlocked so we could upgrade the software from version 6.X to 15.2.  That took some "doing" but we're happy now."

Just to clarify . . are you tethered to Flight Design's limited Skyview software upgrades or are you now free to do Skyview system upgrades to the latest version, like the rest of the free world?

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Having flown both versions, CTLS and CTLSi, if I were to replace my carburated aircraft for a newer model, I would choose a carburated model, again. They are still being made. I saw a brand new AeroJones produced carburated model, 6 mo. ago.

Cheers.

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5 minutes ago, ralarcon said:

Having flown both versions, CTLS and CTLSi, if I were to replace my carburated aircraft for a newer model, I would choose a carburated model, again. They are still being made. I saw a brand new AeroJones produced carburated model, 6 mo. ago.

 

Interesting!  What are your reasons for preference for the carbs?

 

 

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On 7/24/2017 at 10:50 AM, andyb said:

I have about 2500 hours in big-bore Continentals, and about 100 in the CTLSi.  While I can't compare with the carbureted version of the 912, I love the 912i.  Runs like a car.  Hands-down preferred over the Continentals.

Andy

What, you don't miss "hot starting" that Cirrus??

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One minor item not mentioned previously...  I also like the 912iS has an external alternator.  a chunk of that 22 pound weight increase is an added external alternator (and the fuel injection control box).  I remember how turning on the landing light would suck all the juice a 912ULS could produce (bad example, I know, since everyone upgraded to LED).  With an external alternator in addition to the small internal one, you can power whatever accessories you throw at the 912iS. 

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2 hours ago, Adam said:

One minor item not mentioned previously...  I also like the 912iS has an external alternator.  a chunk of that 22 pound weight increase is an added external alternator (and the fuel injection control box).  I remember how turning on the landing light would suck all the juice a 912ULS could produce (bad example, I know, since everyone upgraded to LED).  With an external alternator in addition to the small internal one, you can power whatever accessories you throw at the 912iS. 

I believe that alternator is an "auxiliary" alternator in addition to the rear-mounted stator alternator, correct?  I think it's to make sure the FI system can continue to get juice to keep the engine running if the primary alternator dies.  

The 912 can definitely use more electrical capacity; with duel displays, autopilots, etc the standard alternator is barely adequate.  Add the FI system and I'm guessing some highly optioned airplanes would be over power budget without the second alternator.

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1 hour ago, FlyingMonkey said:

I believe that alternator is an "auxiliary" alternator in addition to the rear-mounted stator alternator, correct?  I think it's to make sure the FI system can continue to get juice to keep the engine running if the primary alternator dies.  

The 912 can definitely use more electrical capacity; with duel displays, autopilots, etc the standard alternator is barely adequate.  Add the FI system and I'm guessing some highly optioned airplanes would be over power budget without the second alternator.

The 912iS power generator is still internal to the engine. It has dual stators of larger capacity than the 912 ULS. Just like the earlier models external alternators can be added in addition to the internal electrical output. This is not something that is standard with the CTLSi.

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12 minutes ago, Tom Baker said:

The 912iS power generator is still internal to the engine. It has dual stators of larger capacity than the 912 ULS. Just like the earlier models external alternators can be added in addition to the internal electrical output. This is not something that is standard with the CTLSi.

Cool, thanks.  I was under the impression the CTLSi had "dual everything" electrical -- batteries, alternators, busses, etc to make sure there was complete redundancy to the FI system.  Is that completely false, or is all that on the list of options?

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On 8/9/2017 at 1:30 PM, ralarcon said:

.Also the fuel injected versions seems to get overheated easily in the Florida weather.

 

The RV-12 cowling has  been modified for the new RV-12 iS model adding four quite large air vents on both sides not required on the ULS engine. .Apparently this is to accommodate the iS engine and aid in cooling the ignition modules.

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9 hours ago, Tom Baker said:

The 912iS power generator is still internal to the engine. It has dual stators of larger capacity than the 912 ULS. Just like the earlier models external alternators can be added in addition to the internal electrical output. This is not something that is standard with the CTLSi.

In either event- (internal or external) there is a higher electrical capacity on the base 912iS v the 912ULS.  That was my intent with the comment.

I was seeing the external alternator kit offered on the CPS website and wasnt thinking.  I actually looked at pics of my engine because I was assuming it was external after seeing it in their parts list!

i stand corrected- on FD it is just the internal "dual stator".

Curious- when starting you raise the rpm to 3000 for a few seconds to visually see the "2nd" stator kick in on the EMS.  Wondering- what about the dual stator requires the increased rpm to "engage"? Isnt the stator mechanical in operation?

 

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10 hours ago, Adam said:

Curious- when starting you raise the rpm to 3000 for a few seconds to visually see the "2nd" stator kick in on the EMS.  Wondering- what about the dual stator requires the increased rpm to "engage"? Isnt the stator mechanical in operation?

 

I don't know the answer, but it could just be that the second stator's output is "masked" or not apparent until sufficient rpm is reached to make the increased output obvious.  Or the second stator's design could be somewhat different or have less output, so it needs higher rpm to register.    These are just guesses though.

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On 8/10/2017 at 2:13 PM, Top Cat said:

The RV-12 cowling has  been modified for the new RV-12 iS model adding four quite large air vents on both sides not required on the ULS engine. .Apparently this is to accommodate the iS engine and aid in cooling the ignition modules.

Yes I think that is what the CTLSi needs.

 

Cheers

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13 minutes ago, ralarcon said:

Yes I think that is what the CTLSi needs.

From what I've gathered on the Van's site, those louvered vents are intended and more functional, to foster additional cooling on the ground. They are more for releasing heat than forcing its circulation.

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55 minutes ago, WmInce said:

From what I've gathered on the Van's site, those louvered vents are intended and more functional, to foster additional cooling on the ground. They are more for releasing heat than forcing its circulation.

I always wedge open the oil access door to aid in dispersing heat after landing. The new vents would no doubt help with that but they seem angled to the air flow too somewhat so probably have a dual function.

I sure would hate it if my modules got too hot!

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6 hours ago, Top Cat said:

I always wedge open the oil access door to aid in dispersing heat after landing.

After shutdown, I do that also.

In the CT, as heat is released through the oil service door opening, fresh air is drawn in from the bottom of the lower cowl. It actually cools down pretty fast that way. Any means to get rid of the residual heat!

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16 hours ago, WmInce said:

After shutdown, I do that also.

In the CT, as heat is released through the oil service door opening, fresh air is drawn in from the bottom of the lower cowl. It actually cools down pretty fast that way. Any means to get rid of the residual heat!

I think you mentioned that sometime ago and I have been doing this ever since. Yes it cools down the engine compartment much quicker.

Cheers

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17 hours ago, WmInce said:

After shutdown, I do that also.

In the CT, as heat is released through the oil service door opening, fresh air is drawn in from the bottom of the lower cowl. It actually cools down pretty fast that way. Any means to get rid of the residual heat!

So why do you want to get rid of residual heat after shutdown?  That isn't something I've heard before.

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Hi Jlang,

To help stop fuel vaporization from heat soaking fuel lines. It isn't as big an issue with FI as it is with the carbs. Many carb aircraft have fuel vaporization after shutdown and then they restart 45 minutes later and the fuel pressure is too low.

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44 minutes ago, Roger Lee said:

Hi Jlang,

To help stop fuel vaporization from heat soaking fuel lines. It isn't as big an issue with FI as it is with the carbs. Many carb aircraft have fuel vaporization after shutdown and then they restart 45 minutes later and the fuel pressure is too low.

Ah, makes sense, thanks. By "after shutdown" I was thinking for the rest of the day.

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On 8/10/2017 at 11:45 PM, Adam said:

Curious- when starting you raise the rpm to 3000 for a few seconds to visually see the "2nd" stator kick in on the EMS.  Wondering- what about the dual stator requires the increased rpm to "engage"? Isnt the stator mechanical in operation?

If it's not generating a high enough voltage, then it can't put any power out onto the bus. 3000 sounds a little high, but I do vaguely recall someone from my last rotax class talking about this.

Anyways, this is the problem with any kind of permanent magnet design. We can't control the power output like we can in an alternator with an electrical field winding. That said though, it would be rather difficult to create a working field coil with the conditions that the stator sits in.

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14 hours ago, JLang said:

Ah, makes sense, thanks. By "after shutdown" I was thinking for the rest of the day.

Well, there are several components under the cowling that can be damaged by heat, including the ignition modules and the regulator/rectifier.  Purging the heat out could have a beneficial effect on the life of those components.  But I don't know if anybody has any good data on those that leave the door open vs. those that don't, and corresponding failure rates.

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