Hot or Not?

[FastEddieB]

Since Eddie has not owned or flown a Cirrus in several years and has never owned a Flight Design Ct his knowledge of current factory operations and information is ZERO. Eddie is not alone, half the COPA members are also former owners and bully new owners with old and out of date information.

 

I on the other hand am the proud owner of a 2016 Cirrus SR22T and received the factory training this year. What I say about the Cirrus and the Flight Design are accurate and from current experience.

All that's interesting.

 

I'm just curious: how does Cirrus go about "requiring" recurrent training on the CAPS system? Not sure they even can, without the FAA mandating that recurrent training.

 

Anyway, I'm still active on COPA, and have not seen any reports of "required" CAPS training. If there is such a thing, please point me towards the actual source of that requirement. I'll also ask Trip Taylor next time I see him, since he's pretty high up in the Cirrus training world. I can see "recommended", but that's different from "required".

[FastEddieB]

...but NEVER descend below the min agl before pulling the chute.

As has been pointed out repeatedly, there is no published CAPS minimum altitude.

 

There is a max descent speed that must not be exceeded before pulling the chute.

Not really. There is an airspeed limitation, but no vertical speed limitation. Unless you meant something else by "descent speed".

[FastEddieB]

Regarding CAPS minimum altitude, from the SR22T POH:

 

Deployment Altitude

No minimum altitude for deployment has been set.This is because the actual altitude loss during a particular deployment depends upon the airplane's airspeed, altitude and attitude at deployment as well as other environmental factors. In all cases, however, the chances of a successful deployment increase with altitude. In the event of a spin, immediate CAPS activation is mandatory regardless of altitude. In other situations, the pilot in command may elect to troubleshoot a mechanical problem or attempt to descend out of icing conditions if altitude and flight conditions permit. As a data point, altitude loss from level flight deployments has been demonstrated at less than 400 feet. Deployment at such a low altitude leaves little or no time for the aircraft to stabilize under the canopy or for the cabin to be secured. A low altitude deployment increases the risk of injury or death and should be avoided. If circumstances permit, it is advisable to activate the CAPS at or above 2,000 feet AGL.

While CAPS activation above 2,000 feet is not necessarily safer than activation at 2,000 feet in terms of the altitude needed to deploy the parachute and slow the descent of the aircraft, there are other risks associated with delaying deployment. Distraction, deterioration in flight conditions, aircraft damage, pilot injury or incapacitation all could take place above 2,000 feet and prevent a timely deployment.

At any altitude, once the CAPS is determined to be the only alternative available for saving the aircraft occupants, deploy the system without delay.

 

(Bolded mine)

[FlyingMonkey]

 

 It was found by Cirrus that those few crashes where the chute would have saved the occupants but was not deployed was due to pilots not pulling - Cirrus calls that failure the 'primacy effect" because the aviation world still does not understand how the chute is to be used.  So I am trying to impress upon you (and others flying a CT) that the presence of the chute makes flying the CT different from planes not equipped with the chute....it is not just an accidental and secondary piece of equipment.  It's too bad you can't take BRS training Cirrus provides it would greatly benefit you since you do have that chute sitting behind you.

 

You seem to be attacking an argument nobody has made.  I do not think of the parachute as a "secondary" piece of equipment, and I have often advocated on this board that using the chute is statistically a better option than an off-airport landing.  

 

I strongly agree with Cirrus' training idea of "Consider CAPS", meaning that in any unusual event the first thought should be "do I need CAPS now?"  Even if you don't need it at that moment, the idea is put in your mind and as the situation progresses you are much more likely to actually use it if you really do need it.

 

However, the key word here is not "CAPS"...it is "CONSIDER".  That doesn't mean immediately going for the handle whenever you encounter an emergency, it means consider the possibility.  In fact I would amend that mindset to apply to all GA airplanes, chute equipped or not, and simply say:

 

Consider All Options.

 

What happens if you are directly over at airport at 5500ft AGL, and the engine fails?  Immediately go for CAPS?  How about a restart!?  How about a descending spiral to land at the airport!?  You have other options, consider them all!  You always have CAPS available if the other options don't work out.  But by gosh the CAPS is *not* foolproof or a 100% guaranteed solution, it has risk associated with it (remember the Cirrus with the chute wrapped around the tail on deployment?).  And sometimes it will have a higher risk profile than another option.

 

Consider All Options. 

 

Always.

[207WF]

Back to the heat topic: 

 

Yes, oil is hot and it is getting worse.  I saw 245 oil temp at a 5100 rpm cruise, OAT 88F at 4500 feet yesterday on my way back from a gear box rebuild.  If I can't get this under control I can't take the bird to OSH this year!  I have tried everything mentioned previously on this thread, except modifying the cowling.  I have three further potential strategies in mind; but the third one is really a question.

 

1. New oil radiator.  I see that Aero Propulsion has a "large size" one, which is 5.16 x 8.50 x 1.65''  The original, I think is the medium size, 3.75 x 8.5 x 1.65".  So the larger one is a bit wider.  Anyone know if this will fit?  Is this the one you are considering, Ed?

 

2. Louvers.  Like you have seen on some Bonanzas.  Suppose I cut a couple of holes in the lower cowl and installed some louvers to encourage more exhaust air?  Expensive mistake if it makes things worse! 

 

3. I saw previously posted here a drawing of "unbalanced" air flow, where air leaking from around the cylinders could impede the flow of hot air out the back of the oil radiator.  I am not sure from where there could be such an air leak.  Anyone have a take on this?

 

WF

[Ed Cesnalis]

Bingo.  found this  Thanks to Jacques I found the cooler for under $200. http://www.improvedracing.com/setrab-oil-coolers/setrab-19-row-series-oil-cooler-p-271.html

 

19 rows or 5.75" tall x 11.25" wide  double the cooling capacity

 

buying direct would save over $1,800 on parts

 

[Ed Cesnalis]

Now I see how I settled on the series 6 19 row cooler.  I found the part number for the cooler in a Canadian CTSW float plane.  The part number (not FD part number) was 50-619-4085. I learned this meant a Seatrab series 6 19 row cooler.

 

Tom P in 2013 said: 'there is a standard specification larger oil cooler and they are making an MRA to support it.   I’ll have Dave try and find out from Customer Care What the FD part number is.  I assume you’d rather make up your own than buy the FD part?'

 

Since it is a standard spec larger oil cooler I assume it fits.

 

Roger, why do you think FD has a standard spec larger cooler?

[207WF]

Here is another crazy idea.   Suppose I cut out every other fin on the water radiator near the center, so as to let the oil radiator get more air flow.  I would gladly trade 10F higher CHTs for 20F lower oil temps.  WF

[FlyingMonkey]

Here is another crazy idea.   Suppose I cut out every other fin on the water radiator near the center, so as to let the oil radiator get more air flow.  I would gladly trade 10F higher CHTs for 20F lower oil temps.  WF

The fins have a lot of surface area for air to flow over, but the frontal area restricting flow is quite low, even for a lot of them. What you are proposing might work, but I can also see it just trashing a good radiator to little effect. I'd give it maybe a 50/50 chance of helping in a measurable way. Those odds would not be enough for me to cut up my radiator, but you might feel like rolling the dice.

[Craig]

Here is another crazy idea.   Suppose I cut out every other fin on the water radiator near the center, so as to let the oil radiator get more air flow.  I would gladly trade 10F higher CHTs for 20F lower oil temps.  WF

 

Were I contemplating this, I would first find out what a replacement radiator would cost and availability?

[207WF]

Couple of updates on oil temps.

 

I went out and measured today, and I already have the larger of the two standard rotax oil coolers.

 

Regarding unbalanced air flow, I noticed an area of potential leakage where the air intake for the plenum that forces air over the top of the cylinders meets the hole in the lower cowl. I had some old, relatively thin baffling material left over from a previous (failed) attempt at an oil temp. solution, so I fashioned some baffles around the male side of the air intake and temporarily affixed them with metal tape. Made sure I had a pretty good seal and test flew. If it made any difference in the oil temps it was probably my imagination.

 

So, I think I am down to ELSA and a larger oil cooler from another manufacturer. I would cut fins out of the water radiator, but it looks like I would pretty much have to break the tack weld and take the two radiators apart to do it.

 

WF

[Roger Lee]

Hi ED,

 

I don't know. It may have been approved when FD was contemplating other services for the CT like an amphib or tow.

 

"Roger, why do you think FD has a standard spec larger cooler?"

[Tom Baker]

I have been thinking about this, and I will throw some thoughts out there. I don't completely agree with Roger that the oil lines are causing an issue. 2 of those lines are on the suction side, and if there were a problem the engine would be starved for oil and pressure would be low. The third line returns oil to the tank. If it were restricted it could allow the oil a longer time to absorb heat in the crankcase, but if it were very restricted it would leave the oil tank empty and the engine starved for oil.

 

Our engine oil has 2 purposes. Lubrication and cooling. There are 3 things that will make the oil hotter. 1. the oil is not transferring the heat like it once did. 2. the oil is in contact with engine parts longer, allowing more heat transfer. 3. The oil is not transferring the heat to away in what ever means of cooling is designed into the system.

 

Things that can change from new. 1. The radiator shock mounts will sag with age lowering the cooler in the opening over time. It would be a cheap fix, and not a bad idea replacing them because of age.  2. I think most are using a different oil than they were when the airplanes were new. the new oil is supposed to be better. I'm not convinced that it is an issue.  3. Build up internally on the oil cooler. It will effect heat transfer, and not cool the oil as well. I have seen this on other GA aircraft, where having the oil cooler professionally serviced has reduced oil temperatures significantly.  4. Build up of dirt on the exterior of the radiator oil cooler. During maintenance I have seen oil run down onto the radiator/ cooler. Even when you think you have cleaned it up completely there is still some oil residue. That residue will attract dust and dirt. This will effect the heat transfer.

[gbigs]

The air cooling whisks heat from cylinder walls (the oil has no role in that).  The radiator cooling whisks heat from the oil lubricating the crankshaft, gearbox, bearings etc. but can be overcome as the oil breaks down.

 

The major role of oil is not to 'transfer' heat...it's to reduce friction and therefore heat.   Over time the oil will break-down and lubricate  less efficiently and that will cause 'excess' heat to be generated.  Another enemy of oil lubrication is blocked oil passages.  Lead in the fuel and varnishes from cooked oil are a major contributor to reducing oil flow efficiency.

 

In our CTLSi we attacked the oil and lead problem by burning Mogas exclusively and by going to Mobil One motorcycle racing oil.  The Mogas has no lead and the racing oil is formulated to last longer and hold up better under high RPM and heat generation.

[FastEddieB]

Let me add a fourth conceivable item to Tom's list of reasons for higher oil temps:

 

4) The engine itself may be producing more heat for whatever reason.

[FlyingMonkey]

I flew yesterday in about 88°F OAT, and my temps never got above 230°F, and mostly stayed around 218-225°F.  The small adjustments I made might have made a difference.  Too soon to say for sure, but I'm encouraged.  There's definitely an oil temp difference between 5200rpm and 5000rpm, below 5000rpm it cools off pretty quickly.

[FlyingMonkey]

 

The major role of oil is not to 'transfer' heat...it's to reduce friction and therefore heat.   

 

Then why is it that many high horsepower engines incorporate larger oil galleys in excess of lubrication needs, as well as oil "squirters" that spray the underside of the pistons (where no lubrication is needed) with oil?

 

The answer is to cool the engine through use of oil.  All engines cool through the use of oil, some are just more radical in how they do it.  Oil cooling is especially important in air cooled engines, because air is a terrible heat conductor compare to liquid coolant in other engines.  Rotax uses all three:  air, coolant, and oil.

 

There is a reason that an oil temp gauge is required equipment by the FAA, but very few automobiles have one.  Air cooling sucks on its own, ask anybody who has driven an old VW through the mountains in the summer.

[Cluemeister]

Air cooling sucks on its own, ask anybody who has driven an old VW through the mountains in the summer.

 

 

I remember as a kid climbing the Green Mountains of Vermont in a VW Bus.  I don't remember an overheated engine, but I do remember wondering if Dad was going to have us get out and push.

[gbigs]

Then why is it that many high horsepower engines incorporate larger oil galleys in excess of lubrication needs, as well as oil "squirters" that spray the underside of the pistons (where no lubrication is needed) with oil?

 

The answer is to cool the engine through use of oil.  All engines cool through the use of oil, some are just more radical in how they do it.  Oil cooling is especially important in air cooled engines, because air is a terrible heat conductor compare to liquid coolant in other engines.  Rotax uses all three:  air, coolant, and oil.

 

There is a reason that an oil temp gauge is required equipment by the FAA, but very few automobiles have one.  Air cooling sucks on its own, ask anybody who has driven an old VW through the mountains in the summer.

 

The more oil the more lubricating capability and the larger engines have more surfaces to lubricate.  One criticism of the SR22T  is Cirrus cut the oil capacity to 8 qts down from 12 qts in the standard Continental TSIO 550.   They did it to make the engine 'fit' inside the cowl design.  This requires a more frequent oil change.

 

By the way...can you explain why Rotax has a radiator?  Why don't the big boys use a radiator?

[FlyingMonkey]

The more oil the more lubricating capability and the larger engines have more surfaces to lubricate.  One criticism of the SR22T  is Cirrus cut the oil capacity to 8 qts down from 12 qts in the standard Continental TSIO 550.   They did it to make the engine 'fit' inside the cowl design.  This requires a more frequent oil change.

 

By the way...can you explain why Rotax has a radiator?  Why don't the big boys use a radiator?

 

Because they are not liquid cooled.  The Rotax uses liquid to cool the heads, which requires a radiator to circulate the coolant.  Your Cirrus is all air cooled, so there is nothing to flow through the radiator.    Are you sure you used to own both of these things?!?  

 

More oil doesn't mean "more lubrication."  There are microns of oil between the parts in an engine, either that oil is there or it isn't, there is not "more" or "less" in that regard.  More oil DOES however, mean that fresh, cooler oil is constantly replacing the oil that gets heated by friction, acting as a heat transfer mechanism and doing, guess what?  Cooling the engine!

[Tom Baker]

The more oil the more lubricating capability and the larger engines have more surfaces to lubricate.  One criticism of the SR22T  is Cirrus cut the oil capacity to 8 qts down from 12 qts in the standard Continental TSIO 550.   They did it to make the engine 'fit' inside the cowl design.  This requires a more frequent oil change.

 

By the way...can you explain why Rotax has a radiator?  Why don't the big boys use a radiator?

 

Does your Cirrus have an oil cooler? I would be surprised if it doesn't. I have never seen a big Continental that didn't have one.

[Tip]

Could the oil pump be weak?

[Tom Baker]

Could the oil pump be weak?

 

If it were I would expect to see a reduction in oil pressure.

[Roger Lee]

Hi Tom,

 

Just got back home from 7 weeks away.

 

"I don't completely agree with Roger that the oil lines are causing an issue. "  

 I don't believe they do always cause the problem, but I have found at least 75%  of them to slow oil flow which causes heat retention. It won't cause an ouil shortage or even show up in the psi or pressure gauge just slows the flow. FD knew about this many years ago with the hose off the bottom of the engine and returns back to the tank that was in a too tight an "S" curve.

 

"and if there were a problem the engine would be starved for oil and pressure would be low."

 This isn't necessarily true unless there is a blockage. The oil lines just have a reduced radius so it only slows, not starves. If you had an oil stoppage you have more serious issues to worry about.

 

 "Build up internally on the oil cooler. Even when you think you have cleaned it up completely there is still some oil residue. That residue will attract dust and dirt. This will affect the heat transfer."

I do believe this can happen. You only got dirt or debris out of the cooler and no where else so it can accumulate more debris fairly quickly if you didn't do it all at once and only piecemeal everything.

 

 

Eddie,

 

"The engine itself may be producing more heat for whatever reason. "

 Absolutely and that's why you must have good diagnostic skills and start at "A" and progress to "Z". failing this may cause you to point the finger at the result and not the cause.

 

 

Andy,

 

"There's definitely an oil temp difference between 5200rpm and 5000 rpm, below 5000rpm it cools off pretty quickly."

Less work less heat and 5500 rpm where ED runs all the time verses us that only run 5100-5300 rpm in cruise will generate more heat and retain it. I've told people a long time ago more rpms usually means more heat and more wear. That said the Bings are set up to run leaner around 4400-4800 and you may see a tad more temp in the EGT's.

 

Hi Tip,

 

"Could the oil pump be weak? "

This would be extremely rare in a Rotax unless you have debris in the pump.

[gbigs]

Because they are not liquid cooled.  The Rotax uses liquid to cool the heads, which requires a radiator to circulate the coolant.  Your Cirrus is all air cooled, so there is nothing to flow through the radiator.    Are you sure you used to own both of these things?!?  

 

More oil doesn't mean "more lubrication."  There are microns of oil between the parts in an engine, either that oil is there or it isn't, there is not "more" or "less" in that regard.  More oil DOES however, mean that fresh, cooler oil is constantly replacing the oil that gets heated by friction, acting as a heat transfer mechanism and doing, guess what?  Cooling the engine!

 

Any engine can be made to be water cooled.  Rotax chose to make their aircraft engines part water and part air cooled.  Why isn't that being done on Continentals and Lycomings?

 

And yes, more oil does mean more lubricating capability.   As I said Cirrus put a smaller sump and reduced the amount of oil on their version of the TSIO 550 K so it would fit in their cowling design.  This now requires more frequent oil changes.   The same oil type is used in the larger sump TSIO 550, but having less of it means the oil breaks down quicker.