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RV-12iS Details

Tony_T

Well Known Member
Patron
Spoiler Alert! If you are at OSH and anxiously awaiting the arrival of Van's new iS airplane and want to discover all the little details up close and personal, then stop reading now. She is on the way today (Saturday) so should be there on display by Monday. Otherwise, I'll share some of the details I learned yesterday at Van's headquarters with you here.
____________________

Of course the fuel injected engine is the main attraction and that will no doubt be
the major source of discussions at OSH.
i-TBDR4VP-L.jpg

This is the airframe systems VR (marked B) and it is cooled by one of the ducts on top of the cowl:
i-3XZbMQ8-L.jpg

The cowl VR cooling duct:
i-fvnZJsw-L.jpg

There is another VR for engine systems. Neither are Ducati.

Some of the bigger details include the center console with the new throttle. The detent is a stop at what is the best economy cruise, as I understood it:
i-DbphG5g-L.jpg

Van's is experiencing significant fuel use improvement and a bit more power. Ask them about it.
The electric flaps are fast but not as fast as the johnson bar. There will now be a flap position indicator on the display. When toggling a Go-Around on the flap switch they will retract in about 3 to 4 seconds.
i-KzqQ97z-L.jpg

I also noticed that the ammeter on the display is "Generator" amps and not "Battery" amps as before. This in my opinion is more useful information if it shows the actual generator output.

And, there are a lot small details that may not be noticed in all the ballyhoo. Nice little details.
Like they added a holder for the oil cap on the oil door:
i-gdPrmx3-L.jpg

Those louvers in the top cowl are to cool the ignition modules, one of the many changes needed to adapt the iS engine to the 12.
i-MvqRsN6-L.jpg


More nice details:
The MLG entry points into the fuselage now have removable covers with rubber seals:
i-TjKTNPP-L.jpg

These I think will be retrofittable.
They have added strengthening gussets to the cockpit rails:
i-5H9RQCS-L.jpg

The gascolator is now behind the rear baggage bulkhead as is the ADSB-in black box. The ADSB antenna is now a small post type like the transponder antenna:
i-6t7pd7p-L.jpg
 
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RV-12iS Details #2

The ADSB antenna now only needs a short coax. No wires or Coax have to be routed through snap bushings in the new fuselage.
i-VVgLXRj-L.jpg


The ELT is now located under the baggage floor with an access cover:
i-phTQSZT-L.jpg


More little details -- headset hangars:
i-XPRtxH5-L.jpg

The upgraded steps come with plugs for the tubing:
i-9B8rgGx-L.jpg

An improved canopy hold open catch and canopy latch:
i-4Zxc9vd-L.jpg

The hold-open catch is easier to engage, and the handle rests on plastic instead of the metal roll over bar.

The translucent filler neck so you can see the fuel when the tank is full:
i-McXMGL8-L.jpg


Some new nomenclature will have to be learned:
i-ZfQjRrT-L.jpg


There is a new muffler based heating system with heater doors for both pilot and copilot sides; an attempt to improve cockpit heat. The old water radiator heating is least effective when the wx is cold.
i-FktGmJg-L.jpg

I did not see a rocker switch for the autopilot. Assume (not always a good idea) that you would need to pull the AP fuse if the AP servos would not let go of the aircraft for some reason.

The optional stab fairings are a good looking fit; lots of rivets are used:
i-DDMwtfv-L.jpg


The lower cowl inlets look a lot different from what we're used to! The coolant radiator and oil cooler are up front. The duct on the lower left side of the cowl is the heater air intake.
i-sjwXN87-L.jpg


There is more to come as development continues, including the panel with an IFR navigator...
 
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I wonder if filler neck could remain in current position behind the rear window and extend with a longer transparent flex hose to the tank?

Maybe Van's could give builders an option for the tank filler location, new or original.

That might be the only thing needed to clinch a deal for me...

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Cowl Material?

Tony is the cowl made of aluminum rather than fiberglass? From the look of the vents on the top it appears to be.
 
I wonder where all the water goes when you fly in heavy rain. Top louvers duct air/water to the ignition modules and the NACA inlet ducts air/water onto the voltage regulator and what looks like the FADEC engine control.
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I wonder if filler neck could remain in current position behind the rear window and extend with a longer transparent flex hose to the tank?

Maybe Van's could give builders an option for the tank filler location, new or original.

That might be the only thing needed to clinch a deal for me...

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notr3n.png

There will be no option.

The hose used (and shown in the photo) is resistant to effects of fuel exposure but it is not a flex(able) hose.
It can be bent slightly but only enough to allow getting it aligned as installed. It would be impossible to bend it aft to a different filler location.
 
The FADEC ECU is in the instrument bay. A lot of Rotax engines are open-air installations. They are probably pretty water proof.
 
I wonder where all the water goes when you fly in heavy rain. Top louvers duct air/water to the ignition modules and the NACA inlet ducts air/water onto the voltage regulator and what looks like the FADEC engine control.
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2enn9r7.png

I was telling Tony while he was taking these photos that we get a lot of amusement out of thinking back to all of the forum discussions that went on when Van's announced not jumping into immediately develop an iS FWF kit for the RV-12.

The general consensus was "how hard could it be" (I find it hard to not start laughing while I'm writing this.....).

Anyone not involved in the process has absolutely no idea, but it was certainly worth it.

Probably the biggest challenge was meeting all of Rotax's component temp. limit requirements.
There was extensive testing done and this airplane as presented meets them all (I am not sure all manufacturers can honestly say that). The numerous openings in the cowl are for very specific purposes to meet all of these requirements. The most challenging task was not meeting the temp. requirements in flight, but after shutting down in hot OAT conditions.

Everything related to wiring/electrical (including the fuse box with the voltage regulators) is seal at all connections, so any amount of rain that does happen to make its way inside should not be a problem.
Representatives of Kodiak (Rotax North America distributor) traveled to Van's a couple of times during the design process and consulted on design decisions as well as auditing the the final design, and they have been very complimentary.
We think we have a first class installation that cools well on the ground and in the air, and provides great cabin heat performance.

If you are at OSH, stop by and take a look. We plan to have the cowl off occasionally to show off our efforts.
 
. . . "We think we have a first class installation that cools well on the ground and in the air, and provides great cabin heat performance.

If you are at OSH, stop by and take a look. We plan to have the cowl off occasionally to show off our efforts."
Scott,

In the Van's RV-12is advertising, it says the new engine cowl is easier to remove and install. How so?
It appears the piano hinge is still used, so how is removal and install any different than the old cowling?

Also, was there any redesign of the lower cowl?
 
I note switches for Fuel Pump 1 and Fuel Pump 2.
Does this mean fuel pump now turned off after take off?
Does this mean that the red cube measurement will now more accurately reflect fuel used, as the return flow is not great with fuel pumps turned off?
 
Tony. Nice report, thanks it answers many questions.
One mistake?it looks like the 912iS uses two Ducati regulators. I hope these do better, they are twice the price.
This is out of the 912iS HMM (look at manufacturers name etched into the edge of the case.)

The good news is there are no bing floats.
The ECU should be reliable, it's made by Rockwell Collins.
https://www.rockwellcollins.com/Products_and_Services/A_Z/E/Engine_Control_Unit_-_Dual_Channel.aspx

So?is there a new fuselage and engine in your future??

Mike

Actually, N912VA, the plane in the pictures, was done that way.
If I were to build another one, I would start from scratch. I enjoy the building part.
 
Scott,

In the Van's RV-12is advertising, it says the new engine cowl is easier to remove and install. How so?
It appears the piano hinge is still used, so how is removal and install any different than the old cowling?

Also, was there any redesign of the lower cowl?

Some people have always had some level of challenge with the ULS installation because of the free hanging oil cooler that has to be captured by the lower cowl during installation. It is actually pretty easy if the alignment of the oil cooler hoses is adjusted correctly but it still required some technique to do it.
With the iS, the oil cooler and coolant heat exchanger are hard mounted to the engine, so all you have to do is lift the cowl in place and install the pins.

The lower cowl is the same over-all shape with an enlarged air exit on the aft bottom (the iS engine with its computer control produces a lot more heat that needs to be dissipated.... just one more of the development challenges that had to be worked though), and the required change to the nose where the oil cooler and coolant heat exchanger are. Also on the left bottom is a NACA inlet for cabin heat air and another on the right side for induction air. The SCAT hose connected between the induction filter air box and the throttle body can be seen in Tony's first photo.
 
I note switches for Fuel Pump 1 and Fuel Pump 2.
Does this mean fuel pump now turned off after take off?
Does this mean that the red cube measurement will now more accurately reflect fuel used, as the return flow is not great with fuel pumps turned off?

In flight both fuel pumps are used full time so that there is no engine failure if one fails.
Just one pump is used for engine starting and taxi, and then during the run-up the second is switched on and the first switched off to confirm they will both run the engine individually, then the first one is switched back on so the are both operating for take-off and during flight.

The fuel flow is very accurate because no red cube is used. All engine info is derived from the CAN bus data in the ECM for the engine. Dynon developed some specific software to interpret and display all engine instrument data as derived from all of the resident Rotax sensors on the engine.

The iS engine always has a high volume return flow (in fact it requires a 3/8" line), but since the computer is controlling fuel delivery through the injectors it always knows exactly how much fuel the engine is burning, so it doesn't even matter how much is being returned to the tank.
 
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The lower cowl is the same over-all shape with an enlarged air exit on the aft bottom (the iS engine with its computer control produces a lot more heat that needs to be dissipated.... just one more of the development challenges that had to be worked though), and the required change to the nose where the oil cooler and coolant heat exchanger are.

Are you saying the engine produces more heat than the S engine or the ECM?
 
FADEC And Header Tank

Im not sure why we are calling this a FADEC (full authority digital engine control). It's a ECU as it looks to me (please tell me I'm wrong, love to have bragging rights) the throttle control is not controlled by the computer, but by a push pull cable similar to the ULS. All the FADEC designs I have seen have the computer controlling the throttle position and if the computer can't control throttle position then it does not have "full authority"

I was also wondering if the new design has some type of header tank for the fuel injection system to vent off any gasses.
 
Im not sure why we are calling this a FADEC (full authority digital engine control). It's a ECU as it looks to me (please tell me I'm wrong, love to have bragging rights) the throttle control is not controlled by the computer, but by a push pull cable similar to the ULS. All the FADEC designs I have seen have the computer controlling the throttle position and if the computer can't control throttle position then it does not have "full authority"

I was also wondering if the new design has some type of header tank for the fuel injection system to vent off any gasses.

https://en.wikipedia.org/wiki/FADEC

<short excerpt>
True full authority digital engine controls have no form of manual override available, placing full authority over the operating parameters of the engine in the hands of the computer.
 
Good job, I'm sure it wasn't as easy as it looks :)

Can you share some of the fuel flow and power specs?

  • Van's is experiencing significant fuel use improvement and a bit more power. Ask them about it.
  • There is more to come as development continues, including the panel with an IFR navigator...
 
In flight both fuel pumps are used full time so that there is no engine failure if one fails.
Just one pump is used for engine starting and taxi, and then during the run-up the second is switched on and the first switched off to confirm they will both run the engine individually, then the first one is switched back on so the are both operating for take-off and during flight.

The fuel flow is very accurate because no red cube is used. All engine info is derived from the CAN bus data in the ECM for the engine. Dynon developed some specific software to interpret and display all engine instrument data as derived from all of the resident Rotax sensors on the engine.

Very nice.
 
Thanks to Van's, and more questions

When Tony and I flew to Aurora Friday we didn't expect to see the new RV-12iS. We assumed it would be gone to Oshkosh. To our surprise when we taxed up and parked, there it was in the hangar! We were welcomed inside and were able to examine the newest RV. Rian and Scott were happy to tell us all about it and answer all of our many questions. They are obviously very proud and excited about their new design and it looks great. (I'm wondering who will start a new build first, me or Tony.) Many thanks to Scott, Rian, Jose, Mitch and Fedosia for the warm welcome. They made for a very enjoyable visit. And they didn't know we were coming, we just showed up.

Scott, a couple more questions if you don't mind. Is there any kind of oil temperature control like the Thermostasis mod that many of us have installed on our 912ULS? And I didn't notice a canopy lock incorporated in the new latch design.
 
The engine.
I presume because of the way the ECM controls the fuel delivery and ign timing.

The ECM is behind the firewall (not in the engine compartment).

It doesn't make sense that the iS engine outputs more heat than the S model since the fuel burn is substantially less. Logically, there MUST be less heat going into the coolant, oil, cylinders and exhaust stream since more energy from the fuel is going into turning the crankshaft. Same power for less fuel burn equals higher thermal efficiency.
 
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Perhaps they're just trying to keep the electronics from going over thermal limit during ground operation and especially after engine shutdown with heat-soaking.

I always leave my oil door open after engine shutdown to allow heat to escape. I'm even thinking about placing a small whisper fan over the opening for 5 or 10 minutes to extract the heat more efficiently. Not my original idea... I saw this once being used on a Cassutt racing plane and I thought it was pretty neat.
 
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Earthx Battery

A lot of nice upgrades
I hope wing tanks are next

Is there any info on the EarthX battery size & model and if the stab fairings will work on the 1st generation 12

Joe Dallas
 
Heat soak

Jim,

That's exactly what they are dealing with and the reason for the louvers on top of the cowl. Scott said there is no problem with heat during flight but after shutdown on a hot day the temps exceeded the Rotax limits. Extensive testing was done and temps measured during development to be certain the sensitive (and expensive) electronic components were protected from heat damage. Problem solved with the additional ventilation provided by the louvers.
 
Canopy question

Was the forward canopy bow (along the lower front edge of the windshield ) re-designed to provide better clearance for the G3X Touch screens?

I'd like to add my compliments to the re-design. It looks great. I may be tempted again!
 
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Interesting. We don't worry about our electronics after a hot shutdown on an air cooled installation. Rockwell does?
 
New member here on the forum. Currently looking at the SLSA version of the RV-12. Will the new 912iS be produced as a factory built unit?
 
A lot of nice upgrades
I hope wing tanks are next

Is there any info on the EarthX battery size & model and if the stab fairings will work on the 1st generation 12

Joe Dallas

Pretty sure they consider the new tank design as safe or safer than wing tanks. Of course, it does take up baggage room.
The EarthX in the plane is an ETX900.
Since the stab and tailcone on N912VA are from an earlier airplane, pretty sure the fairings are retrofittable.
 
Thanks Tony
The Fuel Tank is a lot better than the old design and if you take off the wings on a regular bases it may be worth the risk of a fuel leak in the fuselage ?

The RV12 is a great aircraft, if it had wing tanks for the guys who don't take off the wings it would be the perfect light sport aircraft.
My View

Joe Dallas




Pretty sure they consider the new tank design as safe or safer than wing tanks. Of course, it does take up baggage room.
The EarthX in the plane is an ETX900.
Since the stab and tailcone on N912VA are from an earlier airplane, pretty sure the fairings are retrofittable.
 
It was posted earlier that the new tank is 20.2 gallons with maybe (?) 2 gallons unusable. Offsetting the current 4 gal remaining caution or steep climbs/ go arounds which 'could' cause a stoppage.
With the baggage area being increased to 75 lbs it would be good to have the option to increase the fuel load to 25 gallons with a bigger version of the newly designed( and located) tank. This would be the same as the baggage weight increase.
 
I was telling Tony while he was taking these photos that we get a lot of amusement out of thinking back to all of the forum discussions that went on when Van's announced not jumping into immediately develop an iS FWF kit for the RV-12.

The general consensus was "how hard could it be" (I find it hard to not start laughing while I'm writing this.....).

Funny Scott - I went back and reviewed that thread in detail and didn't find one comment that seemed to indicate "how hard could it be"

What I did see is a lot of Van's customers who are experienced pilots, engineers, and builders discussing the possibility and problems in an educated manner that I hope helped to encourage Van's Aircraft to further explore and succeed in this option.

I have to say that your condescending attitude towards us is putting me off ever ordering another Van's kit.
 
Funny Scott - I went back and reviewed that thread in detail and didn't find one comment that seemed to indicate "how hard could it be"

What I did see is a lot of Van's customers who are experienced pilots, engineers, and builders discussing the possibility and problems in an educated manner that I hope helped to encourage Van's Aircraft to further explore and succeed in this option.

I have to say that your condescending attitude towards us is putting me off ever ordering another Van's kit.

I think the sum total of Scott's comments/input - at least during the time I've been on VAF - should give him a pass for perhaps a momentary indulgence of hyperbole. I sure hope you don't base your decision making around being a Van's customer on one comment. People "inside" any pursuit/profession/industry - in my case healthcare - often are amused by the lack of understanding of the details/complexity/challenges of their work. It's human nature, nothing more or less.
 
When you look at the testing of the 12iS and the 14, you get a tiny, weeny glimpse into just part of what is required to engineer, or re engineer a development or change.

Some of the consistent things about Vans have been the diligence to design, structural analysis and production values among many other things. With that comes hours and hours of what if, how can, would it, I am sure.

Without that, I doubt that many would have been built in the UK.

How about looking at 3 minor things in the 12iS and ask where the ideas may have come from ?

1. - New tank design
2. - Canopy support sub gussets
3. - Rear bulkhead inspection mod

Where did they first get thought about, discussed, suggested and now it looks like they have been incorporated.

We are on building RV #5 now, with #6 in pre planning. I can't think of any other kit I would want to build and the 12's we are now doing are the fastest and most fun of all (except micro Molex which is being changed !).

Swapping a motor from A to B, especially when the new one has loads more "stuff" with it must have been an enormous task and guess what, Vans took the time and opportunity to have a look at other areas which needed upgrading. Mind you, when they get round to gluing canopies on, boy, oh boy, I will be dancin' in the street :D

No, the RV12CEO won't be any less good than the RV12NEO - it will just be different and I am sure they do have great fun at brainstorming sessions. For those who haven't spotted them yet, keep your eyes open for the little bits of Engineer Irony in the prints and plans, they are there if you look...
 
No, the RV12CEO won't be any less good than the RV12NEO - it will just be different and I am sure they do have great fun at brainstorming sessions. For those who haven't spotted them yet, keep your eyes open for the little bits of Engineer Irony in the prints and plans, they are there if you look...

Being a former Boeing employee, a 737 driver and knowing that Van's and Boeing are on the same coast plus a pond and a whole country away from Toulouse, I think we should refer to the RV12 versions as NG and MAX. No foreign FBW monikers allowed :D
 
Funny Scott - I went back and reviewed that thread in detail and didn't find one comment that seemed to indicate "how hard could it be"

What I did see is a lot of Van's customers who are experienced pilots, engineers, and builders discussing the possibility and problems in an educated manner that I hope helped to encourage Van's Aircraft to further explore and succeed in this option.

I have to say that your condescending attitude towards us is putting me off ever ordering another Van's kit.

Sorry you feel that way John, because it wasn't intended that way at all and especially wasn't directed at you. I guess I failed in my use of smiley faces.
 
Wire Harnesses Tidbit

Here is a little tidbit that I got from Ryan from Vans at Airventure. The new RV-12iS has the wiring harnesses traveling down the left and right sides of the fuselage. They are not routed down the center of the fuselage like the current version. Definitely a safer design then current version which is routed next to the fuel lines.
 
Performance numbers

Here is a little tidbit that I got from Ryan from Vans at Airventure. The new RV-12iS has the wiring harnesses traveling down the left and right sides of the fuselage. They are not routed down the center of the fuselage like the current version. Definitely a safer design then current version which is routed next to the fuel lines.

Did they happen to have any performance numbers from their trip out there?
 
The iS engine gets hotter even though it uses less fuel. The explanation is that the ULS engine does not burn fuel efficiently. It wastes fuel. That unburned fuel helps cool the engine. The iS engine does not have fuel cooling, so it runs hotter.
 
Well, yeah. A leaner, more efficient burn raises temperatures, right? It's not just EGT that goes up.
 
Science, not Conjecture

The iS engine gets hotter even though it uses less fuel. The explanation is that the ULS engine does not burn fuel efficiently. It wastes fuel. That unburned fuel helps cool the engine. The iS engine does not have fuel cooling, so it runs hotter.

There is no basis for these assertions. Lower fuel burn for the same TAS means higher thermal efficiency and that means less heat out through the exhaust, oil and cooling systems as I said before.

In my bench testing on the carbed 912 engines while developing EFI back in 2007, I measured the average AFR with a wideband at high power in the 12.6 to 13.3 range. This is approximately best power mixture. Extra cooling would be had only at mixtures substantially richer than this- in the low 11s.



For reference here, .09 is about 11 AFR, .08 is 12.5 AFR and .06 is 16.7 AFR.

To get 20% better fuel economy, you'd have to be running well LOP (16/17 AFR) with optimized ignition timing. This will drop both the EGTs and CHTs- nothing is running hotter. This would be about 25% leaner than best power and you'd lose something around 5-8% power depending on ignition timing, which will cost you some speed.

You could also advance power for the same speed (more MAP and/or rpm) and still get that better fuel economy over the carbed versions.





912 EFI running a decade ago on our test stand. One of our customers who does flight training has over 1700 hours now on his EFI/912 and we have dozens of others with many hundreds of hours each. This was all long before Rotax released their 912iS. Our testing, verified by an authorized Rotax partner showed a 5-7% gain in hp over the carbs and slightly lower fuel burn at similar AFRs. We also saw the EGT spread close from 150 degrees to 30 degrees. The carbed engines have a well known mixture distribution issue which mostly goes away with EFI.

We also provided the EFI for the first twin engined EFI/ Rotax 912 aircraft in 2008.
 
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Just returned from the show and am enjoying a Spotted Cow in the dorm...

Over heard Rian commenting at the show that the "is" showing some nice fuel economy over the uls...some 20-30% improvement, depending on altitude and power setting. Even half these numbers would be very welcome...

The new ship is really nice, with many small, but important improvements aside from the engine, i.e. tank, gear, cowl, canopy latch, console, handhold, cup holder, etc.

Deene
 
I don't know enough about engines to explain why, but the iS engine that Rotax currently sells does indeed require additional cooling capability when compared to the ULS ( the effort required to modify the original cowl exit area, and other details wouldn't have been done if it wasn't necessary).
Representatives of Rotax have confirmed this and have said that many manufacturers have had to make changes to deal with it.

The final design of the RV-12iS allows for a climb at Vy to 10000 ft on a 100 *F day with temps staying in the normal range.
 
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