RV-12 Alternative

[the_other_dougreeves]

Actually 100LL in a 912 should not be defined as a problem...more of an inconvenience. Its true that it is not the best fuel choice, but it is entirely acceptable with a couple of operational changes.

You must use TCP in the fuel to help scavenge the lead.

You must reduce the oil change interval to a maximum of 35 hours because of the lead accumulation that developes in the oil.

Lead is a problem. It's not an insurmountable problem or a safety of flight problem, but it's definitely a problem. It lowers TBO and increases costs.

TCP helps, but from what I have been told by Lockwood, some lead will build up, particularly in the gearbox. Lead will also accumulate in the oil system passages (e.g., in the block), increasing wear.

One problem with TCP is the use of Toluene in the formula. This isn't the best thing to carry in the baggage area.

 

[rvbuilder2002]

Lead is a problem. It's not an insurmountable problem or a safety of flight problem, but it's definitely a problem. It lowers TBO and increases costs.

TCP helps, but from what I have been told by Lockwood, some lead will build up, particularly in the gearbox. Lead will also accumulate in the oil system passages (e.g., in the block), increasing wear.

One problem with TCP is the use of Toluene in the formula. This isn't the best thing to carry in the baggage area.

I have not seen any documentation showing that lead in the engine increases wear and lowers TBO. I have talked with Phil Lockwood some on this exact subject and these were not things he mentioned as issues.

Can you direct me to any info from Rotax or anywhere else that substantiates the increased wear and lower TBO time?

 

[PepeBorja]

I have not seen any documentation showing that lead in the engine increases wear and lowers TBO. I have talked with Phil Lockwood some on this exact subject and these were not things he mentioned as issues.

Can you direct me to any info from Rotax or anywhere else that substantiates the increased wear and lower TBO time?

Visit the Rotax Owner web site and retrieve the 4 stroke service bulletins. Look for the the bulletin SI-912-16 dated August 2006. Section 3.3 deals with avgas. Main points:
Change oil and filter every 25 hours
Use semi-synthetic or mineral oils (see list in SI)
Frequent oil chages are needed to assure the removal of deposits and sludge to avoid wear.

The SI does not indicate anywhere that the use of 100LL will reduce the TBO but it does urge the owner to make sure oil is changed every 25 hours and no more to remove contaminants and avoid wear (how much wear is not specified).

I know two operators with 912 engines that went over 2000 hours each and did extensive x-country work including the Bahamas and even Alaska. They carried TCP to help with the low lead issue. I have only 525 hours and only use 100LL on cross-country work. Most flying is local anyway so that is not a problem for the vast majority of airplane owners. I will be flying to Madison, WI soon to look at a Sonex project. That's 150 NM each way. I fuel up at home and the folks in Madison will help me fuel up there with auto gas. No big deal since we are only dealing with 10 to 12 gallons not 36.

I only burn 100LL as a last, last resort during cross country work. After my long cross country for the year where I rack 16 hours I change the oil right away when I get home. It's only 3 quarts of cycle oil and a Napa gold filter for $20 anyway.

Best bet is to talk to the people that use their engines with 100LL. I know the Titan Factory flies their 2 factory T-51 demonstrators and Tornado demonstrator (912S and 914) using 100LL and they do not seem too concerned about it. They have over 3000 hours on those 3 engines using inflight adjustable and constant speed propellers.

Jose Borja
Elk Mound, WI

 

[the_other_dougreeves]

I have not seen any documentation showing that lead in the engine increases wear and lowers TBO. I have talked with Phil Lockwood some on this exact subject and these were not things he mentioned as issues.

Can you direct me to any info from Rotax or anywhere else that substantiates the increased wear and lower TBO time?

Take Lockwood's (Lockwood Aviation's) class on the 912S and talk to the mechanics who overhaul 912 engines.

Per Rotax, 100LL does not officially change the TBO. Not every engine that uses 100LL will actually see a TBO reduction. However, all engines burning 100LL will see higher operating costs from more frequent oil changes and will probably, from what I understand (our 912 has 26 hours), have a higher cost at overhaul. Lead buildup in the gearbox and oil passages are significant.

 

[KThorp]

What happened to the Europa

What happened to the Europa? It had similar features to the RV-12 (low detachable wings, stabilator, Rotax 912 engine, good performance) but composite construction.

It seems like a great little plane but the original company went bankrupt and they closed their U.S. office. A new company is still selling them in the UK but they don't say anything about U.S. prices or shipping.

 

[rvbuilder2002]

Take Lockwood's (Lockwood Aviation's) class on the 912S and talk to the mechanics who overhaul 912 engines.

Per Rotax, 100LL does not officially change the TBO. Not every engine that uses 100LL will actually see a TBO reduction. However, all engines burning 100LL will see higher operating costs from more frequent oil changes and will probably, from what I understand (our 912 has 26 hours), have a higher cost at overhaul. Lead buildup in the gearbox and oil passages are significant.

The higher operating costs is a give with shorter oil change intervals and the use of TCP.
I was wondering what info was published to substantiate your statement that it caused more wear and lowered TBO.

Also... I am familiar with the Rotax web site and the service bullitens for using 100LL. While talking to Phil Lockwood about using avgas he said they have found that the engines do fine if you use TCP and the Pennzoil non synthetic motorcycle oil on a change interval of 33 hours. This puts you at multipals of 100 hours on every third oil change for completing the recommended 100 engine inspections.

 

[Ken Boyd]

Another thought on the Rotax 912

I have been reading the thread about the pros and cons of the mighty Rotax 912. I agree it is the right engine for the LSA market. Almost everyone is using it including Cessna so these fine folks must know something about this engine and its application. What I would like to know--is there any hope for a fuel injected engine any time soon. Van reports that one of the most difficult things in getting the RV 12 in the air was adjusting the two carbs of the 912. Fuel injection would give better fuel milage and maybe even a couple of extra ponies. The US airforce using a fuel injected 912 for their drone.

Ken Boyd
Waiting for the E-LSA.

 

[PepeBorja]

What happened to the Europa? It had similar features to the RV-12 (low detachable wings, stabilator, Rotax 912 engine, good performance) but composite construction.

It seems like a great little plane but the original company went bankrupt and they closed their U.S. office. A new company is still selling them in the UK but they don't say anything about U.S. prices or shipping.

I looked into building one before I got my Tornado. I have the info package and VHS tape (anyone used them anymore?) available and must be a collector item. The video is very well made and it showed the purpose of the R/W feature by showing the plane in a garage and then towed to the airfield with a fuel stop. A man and a woman unloaded the craft at the field and placed some baggage in the back and off they went. It has some neat video flying low and fast over the coastlines of England along with some loops and rolls. In Europe hangar space is a luxury.

But all dreams have a price. I was looking at roughly $30K in kit costs compared to the $13K I paid for the Tornado. The build time was 3 to 4 times more and I was not comfortable with glass work. Glass work requires hundereds of hours of finish work and goes like this: Lay, fill, sand, fill, sand, fill, sand, fill, sand, fill, sand. Very tediuos work. Aluminum is so much easier.

The deal killer for LSA type of kits is Cost and Construction time. In order for the first owner to be successful the build time has to say at 800 hours or less to remain within the magic 2 year number. I started my Tornado in Nov 99 and was ready for flight by July 2000 with about 600 hours of work from unpacking to final paint polish. I spent 2 years and 1000 hour on the RV7 and was staring at another 600 or more hours when I sold the unfinished kit.

Yesterday evening I was flying formation with a new Zenith XL with a J3300 that is having the 40 hours flown and doing a comparo of HP and RPMs between the two engines. The builder has over 1000 hours of work in it and spent a little over 2 years of hard work including his own paint job in white and yellow.

The plane has a great interior in leather with a center console. Looks almost like a car. The plane is nice looking and flew straight form day one. The only adjustment was a couple of springs for the trim system. The only squack so far is a CO reading in the cabin and they are chasing it. The test pilot tells me it flies like a GA airplane and is very stable in pitch and roll (i.e., heavy controls and hard to roll). A young CFI is doing most of the flying after the test pilot was done. The owner is not a pilot and the CFI will be teaching him the LSA deal and both the test pilot and the CFI think the Zenith makes a good teaching airplane.

I asked theZenith owenr if he would do it again and said no because the time was way too much. IMHO, Kits that take over 800 hours will not do well in sales and if they do there will be 1 flying for every 5 kits sold. When that happens there will be a supply of unfinished kits for us to pick from. I am looking into a Sonex unfinished kit right now and I would be the third owner!

Jose Borja
Elk Mound, WI

 

[PepeBorja]

I have been reading the thread about the pros and cons of the mighty Rotax 912. I agree it is the right engine for the LSA market. Almost everyone is using it including Cessna so these fine folks must know something about this engine and its application. What I would like to know--is there any hope for a fuel injected engine any time soon. Van reports that one of the most difficult things in getting the RV 12 in the air was adjusting the two carbs of the 912. Fuel injection would give better fuel milage and maybe even a couple of extra ponies. The US airforce using a fuel injected 912 for their drone.

Ken Boyd
Waiting for the E-LSA.

Ken,

The carb synch is a ritual we all have to learn. Once you learn how to do it it becomes routine. For the novice it can be frustrating but once you figure it out it is a piece of cake to do. It can be madening but helps a lot to have someone that has done it before show you how to do it. It also has a lot to do in how Vans set up the carb cables. They have to have the same travel and any give in the mounts can cause uneven readings as the butterflies are commanded to open.

There are a few guys that have modified thei 912 engines to use fuel injection. Mostly guys that understand that sort of thing. I believe one if thems sells the parts to do the conversion in South Africa. I imagine the factory reluctance is all about the electronics going south and shutting down the engine along with the liability and litigation that soon follows the grieving widows.

Fuel injection would be nice but the Constant Velocity Bing Carbs do a good job of eliminating the mixture control. Changing the needle position in the carbs helps to adjust the carb for the seasons.


Jose Borja
Elk Mound, WI

 

[PepeBorja]

While talking to Phil Lockwood about using avgas he said they have found that the engines do fine if you use TCP and the Pennzoil non synthetic motorcycle oil on a change interval of 33 hours. This puts you at multipals of 100 hours on every third oil change for completing the recommended 100 engine inspections.

I respect Lockwood very much as they are my service center but the 33 hour advice goes contrary to the Service Instruction dated August 2006. The SI is very clear in specifying a recommended 25 hour interal when using avgas excusively. The old instructions called for 50 hours.

I can understand the precautionary 33 hour to make it 3 times in 100 hours but if it were my engine I would go with the SI's recommended 25 hour interval. Assuming 100 hours per year, 4 oil changes with filter come to less than $100 (Honda GNP 10W-40 and NAPA GOld filter). That's $1 per operating hour. Assuming a generous 1 quart per 10 hours of operation, a Lycoming engine will burn more than that in cost just between oil changes.


Jose Borja
Elk Mound, WI

 

[mbell]

The 912 has dual ignition. Is it dual mags or dual electronic ignition of some sort?

 

[PepeBorja]

The 912 has dual ignition. Is it dual mags or dual electronic ignition of some sort?

No mags.

It has two independent lighting (charging) coils and breakerless electronic CDI (Capacitor Discharge Ignition). There are no moving parts meaning breaker contacts or distributor shafts.

Dual pickups (4 total) signal the electronics to release the spark from each CDI into a top and bottom spark plug. The system uses a fixed stator assembly energized by the rotating crankshaft (just like a lawnmower does). There is nothing to wear, is maintenance free and requires no power. A Fifth pickup is used for the RPM signal.

The leftover energy from the charging coils can be converted to 14V and charge a battery. It is enough to drive the basic electrical needs to include radio, xpndr, strobes and Navs. I can run the landing lights (110W) along with strobes and nav lights for a few minutes but that will bring the voltage below 12V. More load will require the optional alternator kit.

Very early 90's vintage 80HP 912s had a recall on the stators. They have been trouble free since then. I believe the CDI ignition is made by Ducatti.


Jose Borja
Elk Mound, WI

 

[mbell]

Jose,

Thanks. I wanted to be sure it didn't depend on the electrical system, which would mean dual batteries and etc. etc.

Mike Bell
Elk Grove, CA

 

[rvbuilder2002]

Assuming 100 hours per year, 4 oil changes with filter come to less than $100 (Honda GNP 10W-40 and NAPA GOld filter).
Jose Borja
Elk Mound, WI

The only oil available in the U.S. recommended for use with autofuel in the 912 is Pennzoil 4 stroke motorcycle oil. It is not yet endorsed by Rotax through the service instruction (none of there recommended oils are available in the U.S.) but they are supposedly doing more detailed testing on it.

One thing I have learned is that when using 100LL in a 912, using the proper oil is very important.

 

[the_other_dougreeves]

I was wondering what info was published to substantiate your statement that it caused more wear and lowered TBO.

Rotax certainly isn't going to tell us that it reduces TBO, although they do say that it is designed for MoGas, use 100LL only as necessary, etc.

As I understand it, lead tends to build up in the oil passages and lines, even when changing oil at 25 hours. This reduces oil flow, causing more wear. Also, the gearbox gets heavily fouled with lead.

Don't get me wrong - I'm going to use 100LL without hesitation but will perfer MoGas when I can get it. 100LL has some significant advantages, particularly with longer storage times - MoGas has more volatile components and those will evaporate in a few days/weeks.

 

[Mike S]

As I understand it, lead tends to build up in the oil passages and lines, even when changing oil at 25 hours. This reduces oil flow, causing more wear. Also, the gearbox gets heavily fouled with lead.

This is a factor in the type of oil you use. Avaition oils are compounded with ingreadiants to combat the lead problems. Since auto fuel no longer contains lead, the oil mfgs have changed the formula for car oil, and no longer address the lead issues.

This is from the Shell oil guys at Oshkosh.

Makes sence to me, I switched back to aero oil in my plane after talking to these folks.

Mike

 

[the_other_dougreeves]

The only oil available in the U.S. recommended for use with autofuel in the 912 is Pennzoil 4 stroke motorcycle oil. It is not yet endorsed by Rotax through the service instruction (none of there recommended oils are available in the U.S.) but they are supposedly doing more detailed testing on it.

One thing I have learned is that when using 100LL in a 912, using the proper oil is very important.

The Penzoil oil is hard to find, but there are a few good suppliers. $30 per case from Lockwood - your choice of 10-40 or 20-50.

 

[the_other_dougreeves]

This is a factor in the type of oil you use. Avaition oils are compounded with ingreadiants to combat the lead problems. Since auto fuel no longer contains lead, the oil mfgs have changed the formula for car oil, and no longer address the lead issues.

This is from the Shell oil guys at Oshkosh.

Makes sence to me, I switched back to aero oil in my plane after talking to these folks.

Mike

The biggest thing with the Rotax is that you need an oil that doesn't foam. The gearbox uses the same oil system and unless the oil is formulated for such applications, this will make a nice foamy mixture that looks cool but doesn't go through the oil system well. The motorcycle oils are designed for this and don't foam.

Now, whether to use synthetic moto oil or not. From what I understand, synthetics don't suspend lead as well as natural oils and, thus, are not recommended if you burn more than 30% avgas. Mobil 1 makes a Rotax-approved moto oil, but it (and all other synthetics) are not for 100LL users. That means natural oil only. The best one currently available in the US appears to be the Penzoil, although it is not explicitly approved by Rotax.

Aviation oils are explicitly prohibited by Rotax. I suppose what we need is a moto oil with additives to help suspend lead.

 

[Mike S]

Doug, interesting.

I was not aware of the foaming problem, just trying to address the lead.

I wonder what Shell, or one of the other aero oil producers would have to say about this.

Mike

 

[the_other_dougreeves]

Doug, interesting.

I was not aware of the foaming problem, just trying to address the lead.

I wonder what Shell, or one of the other aero oil producers would have to say about this.

Mike

Foaming is also one of the reasons Rotax modified the dipstick in the 912 to a higher level in the tank via a SB / AD.

 

[Harvey]

Moto Oils & 912

I had a 912 ( 80 hp) in my previous aircraft for 11 years, and it was a gem.
I originally used Amsoil 20w-50 Racing Oil but it got a bit expensive, so I switched to Mobil 1 15w-50. At that time, Mobil 1 was the approved oil. Since then, Mobil 1 comes in a range of viscosities mainly suited to autos.
To get the original 15w-50 or the newer 20w-50 you need to go to a motorcycle dealer and get their Mobil 1 motorcycle oil.

I don't think the foaming is so much the issue, although the oil tank does have a mesh to cut back on any foam coming out of the return line, but the motorcycle oils do not have friction modifiers ( bad for clutches) and do have additives that allows the oil to maintain viscosity despite running thru the reduction gears. I also made a point of running unleaded auto fuel, so lead contamination was never an issue. While those of us with Lycomings are worried about the phasing out of Avgas, the Rotax users are laughing all the way to the gas pump...

Martin in Oz

 

[rv12iS-builder]

Alcohol in auto gas for Rotax

Rotax experts,

Can the 912 burn auto gas that has had alcohol added to it?

Thanks,

 

[the_other_dougreeves]

Rotax experts,

Can the 912 burn auto gas that has had alcohol added to it?

Thanks,

I'm not a Rotax expert (no do I play one on TV, but I did stay in a Holiday Inn Express last week), but Rotax officially recommends MoGas with up to 5% ethanol. Lots of users are reporting success with 10% ethanol - so far. "E10" gasoline, as it is known, is becoming more common. We'll have to see how the 912 likes it long-term.

 

[gpiney]

I know a number of ultralight flyers. Since they have started using E10, At least 2 have had their fiberglass fuel tanks 'Melt' from E10. I would like to know what the folks from ProSeal have to say about E10 and cured ProSeal.

 

[jcoloccia]

Ethanol in fiberglass tanks is a definate no-no. The boat guys are having trouble too. I don't know if it depends on the type of resin used (polyester vs. epoxy...I'm guessing it attacks both). What's clear, though, is that it actually seems to attack the glass itself somewhat. A bit bizaare, but that's what it looks like.

I think there are ways to ethanol proofing the tank but I don't really know for sure as I just heard about this in passing from a boating buddie of mine.

 

[Baja_Traveler]

Interesting Paper on the effects of ethanol blended gas on aluminum fuel tanks - some other points to consider...

 

[Bitsko]

A few years ago my son was interested in the Sonex. I remember Tony Spicer's name as being one of the first Sonex builders. IIRC, there was a feature article on him in either Sport Aviation or Kitplanes magazine.
Tony, if your RV-3B turns out as neat as your Sonex, it will be a trophy winner. Glad to have you in our midst.
Don

I'd be more interested in owning Tony's DAD'S airplane, if he's the same Tony Spicer who's name was stencilled on the nose of a P-51.

 

[RV6junkie]

Could someone explain to me why there is a thread with 177 replys that advocates alternatives to the RV-12 - IN AN RV-12 FORUM.

Maybe I'm a little sensitive, but it just seems all to hateful to me.

 

[the_other_dougreeves]

Could someone explain to me why there is a thread with 177 replys that advocates alternatives to the RV-12 - IN AN RV-12 FORUM.

Interesting question, although I don't think the thread is saying that the RV-12 is a bad choice ...

I think it has to do with the LSA market vs the "traditional" RV market. How many competitors does the -7/8 line have? Not many. The -9? Again, not that many. The "traditional" RV series has the blend of qualities that makes for, to use the phrase, "total performance" - aerobatics, fun flying, STOL, long-distance traveling ....

The LSA market is much different - more crowded. There are lots of direct competitors and the -12 is a newcomer to the field when compared to the 601XL, Sonex, factory built LSA, etc.

So it makes more sense to me that there should more discussion about the -12 vs other designs. Discussion isn't bad in my book and can improve the design - remember that the -12 is a proof of concept and there is the potential that Van's will listen to our comments and/or comparisons to other designs.

 

[Phyrcooler]

Could someone explain to me why there is a thread with 177 replys that advocates alternatives to the RV-12 - IN AN RV-12 FORUM.

Actually - if you read through the thread - it is very little discussion on alternatives... and a lot of wondering into the Rotax VS. ?? and other topics.

And some of the voiced opinions probably have changed since this was written - since the RV-12 has flown, and what little info we have received is pretty positive on its performance.

I think that Doug maybe should consider locking threads that are older than 3 months since the last post. That forces us to new conversations and ideas! (But the old are still accessible and readable). JMHO.

 

[rv6ejguy]

I've been scanning back over this topic recently and can offer a couple of things about the Rotax. Yes, aftermarket EFI will be available sometime this year for the 912 series engines. For people using 100LL, Decalin Chemicals makes a lead scavenger which is less toxic than the TCP stuff and cheaper. For cross country work, you can carry a bottle of this along when 100LL is the only available fuel.

http://www.decalinchemicals.com/

As far as the Jabiru/ Rotax debate goes. Jab has a long ways to go to approach the worldwide, documented, professional network and support that Rotax already has in place for their engines not to mention multi-country certification. Jab was still doing major revisions to problem areas of their engines as late as last year. While I hope they now have problems licked, this remains to be proven by having hundreds of engines go to TBO without problems. I wish them well. A little competition in this market is healthy and frankly with the demand now for LSA powerplants, Rotax cannot currently keep up.

 

[Tony Spicer]

I'd be more interested in owning Tony's DAD'S airplane, if he's the same Tony Spicer who's name was stencilled on the nose of a P-51.

That would be Tony Boy. P-51B sn 43-6880. Been at the bottom of the English Channel since 3/5/44.

But there will soon be a Tonyboytoo.

Tony, RV-3B finishing