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Interesting Takeoff This Morning

todehnal

Well Known Member
It was a cool morning as we left on our 90 nm flight heading to a breakfast fly-in, located in central Tenn. My pre-flight began with an hour of preheat. The start was quick, as was the warm up, and the flight down was beautiful, and uneventful. After a 1 1/2 hour of breakfast and hangar flying, we were ready to head home. I was surprised at how cool the engine was. It started fine, but I held things up a bit, getting the oil temp up to 120. As soon as it got there, I departed. At full throttle, and at about 50 feet above the runway, the little girl started hollering at me "Engine Speed" Engine Speed" She got my attention! Sure enough, I'm at 5250 rpm, and it is RED, and flashing at me!! Scared the (^@p out of me! I finally figured it out, and it didn't last long. My guess is that the oil was up to temp, but the water wasn't. As soon as I took off, my oil temp must have dropped enough to set off the alarms. I was too busy flying the airplane to notice how far the oil temp dropped, but the alarms only lasted for 10 or 15 seconds. Wheeew! Anyone else experience this?
 
I've experienced this once. SkyView equipped -12. I was descending at 5500rpm and had intermittent oil temperature readings on the gauge for about a minute, fluctuating rapidly down to zero and back to normal. Every excursion below the magical 120, I'd get the engine speed warning. It only happened once, and I chalked it up to a brief intermittent connection.
 
If you depart on a cold day with the oil temps at 120.... the ram air will cool the oil back down below 120 and you get the warnings. No loose connections. I don't think it's a big issue as it will quickly warm up above 120. The run up should be done above 120 anyway, so that should give you a few degrees higher for takeoff. The water temp will have nothing to do with engine over speed warnings. The only caution I know of on skyview is too high coolant temps.
 
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I missed mentioning tat this is a Skyview system. Also, my comments about the low water temp on takeoff was not meant to point to it as the cause of the engine speed alarm, but as a possible cause for the brief lowering of the oil temp early in the takeoff run with the oil temp only at 120. My thoughts were that with the higher rpm on takeoff, the water pump could move more cold water through the engine, thus temporarily lowering the oil temp. In retrospect, it was a non event, but the alarm did get my attention.
 
If you depart on a cold day with the oil temps at 120.... the ram air will cool the oil back down below 120 and you get the warnings. No loose connections. I don't think it's a big issue as it will quickly warm up above 120. The run up should be done above 120 anyway, so that should give you a few degrees higher for takeoff. The water temp will have nothing to do with engine over speed warnings. The only caution I know of on skyview is too high coolant temps.

100% agree with this answer. Here in N. Texas I never had this problem but I am aware of others when taking off in Cold Weather and oil at 120f having the alarm go off as ram air cools the oil below 120f for a few seconds.
 
I fly D-180 EFIS and perhaps there is a difference in how the Skyview operates. As an example? my oil temp and pressure have five arcs as follows: lower red, lower yellow, green, upper yellow, and upper red. I can operate in either of the yellow arcs with no alarm. For instance, I can takeoff with oil temp in yellow arc at say 110F and have green arc on tach not opened up yet with no alarm.

Like my grandmother used to say - Such things they have now... :D
 
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Jim,
You may want to check your alarm settings on the D-180. If you increase RPM above 2500 when the oil temp is less than 122? the normal setting gives an alarm. The alarms can be suppressed in the menus.
 
It was a cool morning as we left on our 90 nm flight heading to a breakfast fly-in, located in central Tenn. My pre-flight began with an hour of preheat. The start was quick, as was the warm up, and the flight down was beautiful, and uneventful. After a 1 1/2 hour of breakfast and hangar flying, we were ready to head home. I was surprised at how cool the engine was. It started fine, but I held things up a bit, getting the oil temp up to 120. As soon as it got there, I departed. At full throttle, and at about 50 feet above the runway, the little girl started hollering at me "Engine Speed" Engine Speed" She got my attention! Sure enough, I'm at 5250 rpm, and it is RED, and flashing at me!! Scared the (^@p out of me! I finally figured it out, and it didn't last long. My guess is that the oil was up to temp, but the water wasn't. As soon as I took off, my oil temp must have dropped enough to set off the alarms. I was too busy flying the airplane to notice how far the oil temp dropped, but the alarms only lasted for 10 or 15 seconds. Wheeew! Anyone else experience this?
todehnal,
I made my first flight today in Ohio with temperatures just above freezing and had a similar issue with the oil temps dropping just below 122 on my second take-off climb. Did you figure out a solution to correct this? I'm thinking about adding a shield to the oil cooler to block 50% for starters to see if that helps.

MJ
RV-12, Liberty Township, OH
N418MJ
[email protected]
 
Buy a roll of aluminum tape at Home Depot.
Suggest 1.5 inches wide.
It should have an adhesive backing. I prefer the brand which has the light brown paper on the back side, which will be peeled away for use.
Cut a strip of tape, about the width of the radiator.
Apply the strip horizontally, across the top of the radiator. Leave a tiny corner of the strip “dog-eared,” to ease eventual removal (when seasonal temps warm up).
Try a single strip first, to see if that is adequate. If still too cold, add a second strip or at least, an additional shorter strip, until temps increase to a normal level.

That has served me well over the last 4 years.
 
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Or fit a Thermostasis oil thermostat kit. Temp reaches 120 (50 degrees C) much quicker and temp stays up even during long, low power descents. I was using foil tape to blank off oil cooler. Thermostasis is a much better solution.

Jack
 
I have used the adhesive-backed aluminum foil tape methods with a number of aircraft installations in the past and found it to be a simple and effective solution.

I surmise from this thread that the 912S does not come with a thermostat for the oil cooling system. Anyone know if the 912iS does with all the other improvements?
 
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cool

I think a simple oil thermostat would do? I'm still in building phase (with no engine on the fuse, yet), but I had a Kitfox with 912 of it, and those oil- and water thermostats works really, really well. Warmed up in several minutes during wintertime. No buttons or valves, never had any troubles with them.
Lots of plumbing, though. And I'm not sure whether that will fit under the -12's cowl. If so I will put them in, beginning with oil thermostat.
 
An oil thermostat will shorten warm up time because engine heat will not be wasted warming up the oil in the oil cooler and will not be wasted heating up the air flowing though the oil cooler.
 
The 912iS does not have an oil thermostat, even if it did it would made little or no difference to warm up time. Stick with the foil tape to blank off oil cooler.

I live in upstate NY where we have a long and cold winter. This year we had our first below zero temps in November. 🥶 I have been using a Thermostasis for many years on the 912ULS with great results. I am curious as to why you feel it would not have the same results on the 912iS.
 
Oil Therm - -

This was one of my first invented mods. It absolutely works, and very well. Many people copied my design, and now it is available as a kit from a USA supplier.

Another invention was my "Heater Damper Door", which also works very well in cold weather, if you like to stay warm.
 
I'm in the process of installing a cable operated oil cooler door. The door mounts over the oil cooler. I used the two top bolts of the cooler to mount it to. It covers about 90% of the cooler. Van's catalog has one as well as Spruce. I paid $110 for the door and $65 for the cable, the cable has a push button lock so it doesn't creep. The cable comes down behind the oil filter and is clamped in place. I made a bracket to mount the cable to in the cockpit, under panel area. When warmer weather arrives the door can be easily removed and the cable end stowed safely. I sat or 10 min. the other day when it was 40 out waiting to reach 120 and at cruise it was only in the 150's, we'll see how it works and I'll let you all know. If I can figure how to post pics I'll do so...I don't understand what they mean by needing the URL for my pics.
 
bobg56, pictures can not be posted on VansAirforce. They must be uploaded to some other website. Then you provide a link to that website on VansAirforce.
 
We worked with John Peck (BigJohn), Rob R, and a few others to optimize the installation of the 190 degree Thermostasis unit on the RV-12. We have also adapted this installation to a variety of other experimental aircraft with the 912ULS engine.


Reported results have been very good. Warmup times are reduced by close to 50% and inflight temperatures remain higher and more consistent than without the thermostat installed.

For those who are replacing the factory Rotax oil lines at the 10 year mark, we are able to do a COMPLETE set of oil lines INCLUDING a thermostasis unit and fittings for less cost than the stock OEM rotax hoses. And, the hoses we sell all have a 10 year warranty on them. (Please note that the Thermostasis kit alone does not include the Return oil line on the bottom fo the engine which must be purchased separately. We do that so that customers have the choice of whether or not to replace that line or not as it is not part of the thermostasis oil line routing)

Have a great weekend!
Steve
 
Another data point regarding oil thermostats........

The Rotax 912iS engine has very detailed and specific design requirements regarding the installation on an airframe.
A huge amount of engineering effort was invested to assure the RV-12iS meets all of the installation requirements stipulated by Rotax, and then compliance of the installation was proven with detailed testing.

One of the tests required by Rotax is related to flow resistance within the oil cooler circuit. Testing showed that a thermostasis oil thermostat added enough flow resistance that the test requirements couldn't be met, regardless of the fitting and hose configuration.

Rotax has periodically updated the installation requirements for their engines over the years and this test was at some point added to the ULS engine installation manual as well. Anyone installing an oil thermostat should do these checks or ask the vendor that is providing the installation kit, if the can certify that the checks have been done (particularly if you engine is still under factory warranty).

One of the few differences in the core engine between the ULS and the iS is that the iS has a higher flow volume oil pump. All of this info should be taken into consideration when contemplating installation of an oil thermostat.

BTW, for reasons not entirely understood at this point, the iS version of the engine warms up during ground operations much faster than the ULS version does (even with the redesigned cowling and both heat exchangers located directly in the prop blast).
 
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The Rotax 912iS engine has very detailed and specific design requirements regarding the installation on an airframe.
A huge amount of engineering effort was invested to assure the RV-12iS meets all of the installation requirements stipulated by Rotax, and then compliance of the installation was proven with detailed testing.

One of the tests required by Rotax is related to flow resistance within the oil cooler circuit. Testing showed that a thermostasis oil thermostat added enough flow resistance that the test requirements couldn't be met, regardless of the fitting and hose configuration.

Rotax has periodically updated the installation requirements for their engines over the years and this test was at some point added to the ULS engine installation manual as well. Anyone installing an oil thermostat should do these checks or ask the vendor that is providing the installation kit, if the can certify that the checks have been done (particularly if you engine is still under factory warranty).

One of the few differences in the core engine between the ULS and the iS is that the iS has a higher flow volume oil pump. All of this info should be taken into consideration when contemplating installation of an oil thermostat.

BTW, for reasons not entirely understood at this point, the iS version of the engine warms up during ground operations much faster than the ULS version does (even with the redesigned cowling and both heat exchangers located directly in the prop blast).

EXCELLENT information Scott, thank you! This is information unavailable builders/consumers, we would have to dig very hard to find it and even then may not. We really should split info like this off into a thread by the same name, in fact I might do that.

I'd bet that the iS warms up faster because it is running leaner in almost all conditions due to the computer controlled fuel injection ? closer to a stoichiometric mixture, which would yield higher combustion temperatures than the likely overly rich cold start circuit the carbs provide, thus heating the engine faster. This is a trend I see across all model gas engines both auto and motorcycle.
 
Thermostasis ONLY approves the thermostat that we utilize in our RV-12 kits for the 912UL and 912ULS engines. This thread has drifted from the 912ULS to the 912iS engine.

While we have had great success with the 912ULS engines, we have no data from the thermostat on iS engines.

If Thermostasis decides to do the testing on the iS engines, we would be happy to work on a hose installation kit. However, it sounds like the iS engine warms up quickly on its own and may not see the benefits that the 912ULS does.

Here is a link to the Thermostasis specific FAQs for Aircraft Installations

http://oilthermostats.com/aircraft/
 
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Thermostasis ONLY approves the thermostat that we utilize in our RV-12 kits for the 912UL and 912ULS engines. This thread has drifted from the 912ULS to the 912iS engine.

Not a thread drift in my opinion.

As I mentioned already, Rotax has implemented the same oil system flow restriction test requirement on the ULS engine that I mentioned did not pass on the iS engine. They have been selling their thermostatic valve for far longer than the test requirement has been in place

Will the ULS engine pass with a thermostasis installed? I don't know. I have only been involved with doing the testing on an iS engine. If no one else has ever tested it, then it is an unknown. I would think that if Thermostasis had, they would mention it because the requirement for the restriction test is rather new.
 
Question

Thermostasis ONLY approves the thermostat that we utilize in our RV-12 kits for the 912UL and 912ULS engines. This thread has drifted from the 912ULS to the 912iS engine.

While we have had great success with the 912ULS engines, we have no data from the thermostat on iS engines.

If Thermostasis decides to do the testing on the iS engines, we would be happy to work on a hose installation kit. However, it sounds like the iS engine warms up quickly on its own and may not see the benefits that the 912ULS does.

Here is a link to the Thermostasis specific FAQs for Aircraft Installations

http://oilthermostats.com/aircraft/
Not sure this answers Scott?s point in para 3 of post 21 above??
 
Not sure this answers Scott’s point in para 3 of post 21 above??

The truth to this is that we are not the manufacturer of the Thermostasis. Nor do I know to what exact extent the Thermostasis unit has been tested in regards to the NEW Rotax requirements for the 912ULS engine. I am awaiting more information on that from the manufacturer.

What I do find interesting in the Rotax manual is the following statement "When operating at low temperatures, installation of an oil thermostat, parallel to the oil cooler is highly recommended"


Given that statement in the manual....and the fact that a lot of RV12 aircraft are being operated in cold weather environments, I can only assume that Vans is working on releasing a thermostat installation to be 100% compliant.

Is that correct, Scott?

I do know that at the time the Thermostasis was designed it complied with known Rotax restrictions. I also know that there are many many units flying on many different aircraft types all over the world. Every response I have ever heard about the unit has been positive. That doesn't mean that it is compliant with the new Rotax manual...just that in real world experience it seems to work well.

Though we are not involved with the manufacture or design of the unit, we have helped with many Thermostat installations by providing hose assemblies to hook the units up to the engine. We have one on our RV-12 and love it. That's the beauty of these airplanes. Some may want to use duct tape on an oil cooler. Others want a bit more of a "refined" solution. Neither is wrong or right. Personally, I would never go back as the benefits of the Thermostat in all aspects of cold weather operations far exceed any potential drawbacks IMHO.

The Rotax 912iS engine has very detailed and specific design requirements regarding the installation on an airframe.
A huge amount of engineering effort was invested to assure the RV-12iS meets all of the installation requirements stipulated by Rotax, and then compliance of the installation was proven with detailed testing.

New information is always good, as it leads to product improvement and additional testing. With that said, the more paperwork that exists, the less likely it is to be 100% compliant with any specific installation manual.

Here is an example that jumps out at me. The new RV12iS oil hoses being shipped by Vans are Stratoflex 124-8 hoses. They have a minimum ID of .406". In the 912iS installation manual, it specifies a minimum ID of .430 inches. Now, I do not think that this is any issue at all. .406 +/- a few thousandths is very close to the spec of nearly all standard -8 conductive Teflon hose assemblies. Our -8 hoses are an ID a few thousandths larger and Aeroquip 666 hoses are the same as the Stratoflex hose. This may seem like a minor issue (and it is), but it is not 100% compliant.

At some point, I think you have to trust the manufacturer and their reputation. Van's builds a great airplane. I don't think that the RV12iS engines are about to start failing because the ID of the hose Vans supplies is .024" smaller than what the Rotax manual says they should be.

This is definitely an interesting discussion.
 
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The truth to this is that we are not the manufacturer of the Thermostasis. Nor do I know to what exact extent the Thermostasis unit has been tested in regards to the NEW Rotax requirements for the 912ULS engine. I am awaiting more information on that from the manufacturer.

What I do find interesting in the Rotax manual is the following statement "When operating at low temperatures, installation of an oil thermostat, parallel to the oil cooler is highly recommended"


Given that statement in the manual....and the fact that a lot of RV12 aircraft are being operated in cold weather environments, I can only assume that Vans is working on releasing a thermostat installation to be 100% compliant.

Is that correct, Scott?

I do know that at the time the Thermostasis was designed it complied with known Rotax restrictions. I also know that there are many many units flying on many different aircraft types all over the world. Every response I have ever heard about the unit has been positive. That doesn't mean that it is compliant with the new Rotax manual...just that in real world experience it seems to work well.

Though we are not involved with the manufacture or design of the unit, we have helped with many Thermostat installations by providing hose assemblies to hook the units up to the engine. We have one on our RV-12 and love it. That's the beauty of these airplanes. Some may want to use duct tape on an oil cooler. Others want a bit more of a "refined" solution. Neither is wrong or right. Personally, I would never go back as the benefits of the Thermostat in all aspects of cold weather operations far exceed any potential drawbacks IMHO.



New information is always good, as it leads to product improvement and additional testing. With that said, the more paperwork that exists, the less likely it is to be 100% compliant with any specific installation manual.

Here is an example that jumps out at me. The new RV12iS oil hoses being shipped by Vans are Stratoflex 124-8 hoses. They have a minimum ID of .406". In the 912iS installation manual, it specifies a minimum ID of .430 inches. Now, I do not think that this is any issue at all. .406 +/- a few thousandths is very close to the spec of nearly all standard -8 conductive Teflon hose assemblies. Our -8 hoses are an ID a few thousandths larger and Aeroquip 666 hoses are the same as the Stratoflex hose. This may seem like a minor issue (and it is), but it is not 100% compliant.

At some point, I think you have to trust the manufacturer and their reputation. Van's builds a great airplane. I don't think that the RV12iS engines are about to start failing because the ID of the hose Vans supplies is .024" smaller than what the Rotax manual says they should be.

This is definitely an interesting discussion.


Steve
I am not going to respond since your post seems to be be judgmental in tone.... like you are trying to prove something?
If that is how you took it, my original post was not intended that way. Most of what I post here is intended to be informational for people building and flying these great airplanes. It was information that I knew was not common knowledge, but is important.
I will say that regardless of the hose diam not exactly meeting the I.D. requirement is not an important factor. Rotax is clear that the design of the external systems related to the engine installation are the responsibility of the aircraft manufacturer. Passing all of the prescribed tests (including the oil system pressure drop test that has been mentioned here) is the true bench mark for the installation.... not whether it matches up with all of the recommendations made in the documentation. Those are guidelines to help with the design and installation process.... even if they are followed to the letter, the tests still need to be done to verify the installation meets the requirements.
BTW, Rotax engineering in Austria and the USA distributor have both publicly gone on record saying that the RV-12iS engine installation is one of the best engineered they have seen.....

BTW, the "When operating at low temperatures, installation of an oil thermostat, parallel to the oil cooler is highly recommended"
statement has been in the manual for many many years. The pressure drop test has not. It doesn't seem that just because Rotax previously recommended the use of one that it alleviates the pressure drop test requirement. In fact just the opposite since as already mentioned, they put the burden on the aircraft manufacturer or installer to assure all requirements are met.
 
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BTW, Rotax engineering in Austria and the USA distributor have both publicly gone on record saying that the RV-12iS engine installation is one of the best engineered they have seen.....

I wouldn't expect less. Thank you Van's for the fine aircraft you design and furnish as kits that can be built with high precision...
 
Steve
I am not going to respond since your post seems to be be judgmental in tone.... like you are trying to prove something?
If that is how you took it, my original post was not intended that way. Most of what I post here is intended to be informational for people building and flying these great airplanes. It was information that I knew was not common knowledge, but is important.
I will say that regardless of the hose diam not exactly meeting the I.D. requirement is not an important factor. Rotax is clear that the design of the external systems related to the engine installation are the responsibility of the aircraft manufacturer. Passing all of the prescribed tests (including the oil system pressure drop test that has been mentioned here) is the true bench mark for the installation.... not whether it matches up with all of the recommendations made in the documentation. Those are guidelines to help with the design and installation process.... even if they are followed to the letter, the tests still need to be done to verify the installation meets the requirements.
BTW, Rotax engineering in Austria and the USA distributor have both publicly gone on record saying that the RV-12iS engine installation is one of the best engineered they have seen.....

BTW, the "When operating at low temperatures, installation of an oil thermostat, parallel to the oil cooler is highly recommended"
statement has been in the manual for many many years. The pressure drop test has not. It doesn't seem that just because Rotax previously recommended the use of one that it alleviates the pressure drop test requirement. In fact just the opposite since as already mentioned, they put the burden on the aircraft manufacturer or installer to assure all requirements are met.


Scott,

Actually, the post was not intended to be judgemental at all. Like you, we want the safest and most efficient installations possible.

There are some legitimate questions that it would be nice if you could answer.

1. Since Rotax does recommend the installation of an oil thermostat when operating at low temperatures, is Vans working on a "Van's approved" Thermostat installation. If so, which Thermostat unit is being used?

2. Given your contacts at Rotax, can you find out the reason this test was added to the 912ULS engine? If they uncovered a safety issue, I am hoping that a service bulletin would go out requiring this test on all existing installations both with and without a Thermostat. Also, do you happen to know if this test was also performed on an rv-12 with the 912ULS engine in the standard configuration to verify the installation on the existing RV-12 Fleet?


There are over 1,400 Thermostasis units in existence with no reported instances (that we know of) of issues with the 912ULS engine. That's a pretty good track record. That doesn't mean that it is in compliance with the new test Rotax just added. It just means that it certainly APPEARS to work, and work well. The vast majority of these installations were done by individual customers on their individual aircraft. So, many of them are different.

We have no skin in this at all. We don't manufacture the units. We just help owners who want hoses for it. It's a VERY VERY small part of what we do.

Regarding the oil hose diameters...... I completely agree with you. There is no issue with it at all. Though the 912iS installation does not comply with ALL printed requirements, the end result is a system that functions well and yields a safe, well designed, and efficient product. That's all that anyone cares about. I would expect nothing less from Vans.
 
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Clarification.....

The requirement for testing the pressure drop on the oil system is not "New".
It has been in the documentation for a couple years I think.

To me it doesn't matter what Rotax's reasoning was for setting the requirement. It needs to be met regardless, and the only way to verify that is to do the test.
 
The requirement for testing the pressure drop on the oil system is not "New".
It has been in the documentation for a couple years I think.

To me it doesn't matter what Rotax's reasoning was for setting the requirement. It needs to be met regardless, and the only way to verify that is to do the test.


Has Vans performed this specific Rotax test procedure on the legacy RV12 with the 912 ULS engine?
 
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Has Vans performed this specific Rotax test procedure on the legacy RV12 with the 912 ULS engine?

Yes

Multiple times, but not with an oil thermostat installed, because Van's does not offer that as a kit. Anyone that does, it would be their, or the installers responsibility to verify compliance with the test requirement.

Vans, instead of an oil thermostat, offers an oil cooler and radiator block off kit as an option for the ULS RV-12.
 
Yes

Multiple times, but not with an oil thermostat installed, because Van's does not offer that as a kit. Anyone that does, it would be their, or the installers responsibility to verify compliance with the test requirement.

Vans, instead of an oil thermostat, offers an oil cooler and radiator block off kit as an option for the ULS RV-12.

Thanks... That?s great information!!!!! Much appreciated.
 
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