EGT is not a "real" temperature

[PTK]

I enjoy Mike Busch's seminars and have learned a ton and continue to learn from him. I have a hard time grasping this concept. He says that EGT isn't a real temperature. Can someone please explain this. I understand the variables of probe position, vlalve timing etc. but these don't change and gases coming out of the exhaust valve are at a certain temperature aren't they? If  we say the |EGT| is meaningless can't we say the same thing about CHT for example or OT?

 

[ArtVandelay]

During combustion, it's like 3000, but as the gases expand, they cool rapidly, as the gases are expelled the probe is heated, when exhaust valve closes, heating stops, they cool....you are just getting and average of all these fluctuations.

CHT doesn't fluctuate, the cylinder has thermal mass, so it's a real temperature.

thats the short version...

[carusoam]

P,

I get the feeling Mike B includes a much wider audience than the more narrow range of only Mooney pilots.

The EGT includes many variables with it, making it a challenge to use in it's raw data form.  It is an extra challenge to compare data between planes.  It is near impossible to use the raw data from different days on different planes.

It may also be a way of bringing the reader's focus from the raw data and putting it where it belongs on the relative difference of EGT in °F (LOP or ROP).  More writer's and audience's limitations than 'real' temperature.  Using the technique of exaggeration, Mike B takes on the risk of losing one audience member to simplify the discussion and maintain the larger audience's interest in a mathematical discussion.

Back in the day...

60's planes with their single EGT didn't even get a calibrated scale.  The pilot selected a line on the gauge where peak normally occurred. Some engines may actually get rough before a peak can actually occur. The scale was calibrated in lines of 25°F or so.  No actual temperatures were on the dial.  With a carburetor, running LOP was not even a consideration.  Some TCs have really thick armor making them slow to react to temp changes.

The single peak temp would vary significantly with changes of altitude and OAT.

The M20C's instrument is a thing of beauty.  It's TC is the power source for the instrument.  It is always on.  It Can't run down the ship's battery.

Things improved over time...

Modern instruments display actual data on a screen.  Their EGT probes are installed in standard locations at the factory.  A modern Mooney will put the ship's EGT probe in the confluence of three exhaust pipes capturing the power pulses of multiple cylinders.  This gauge is calibrated with actual numbers on the analog or digital display.  Leaning (ROP) during climb is done using this real single point data.  The procedure is in the modern POH, as is LOP Ops.

Ultimate use of EGT...

A TC'd engine uses a single EGT reading to observe the exhaust stream powering the turbo.  Too hot, the turbo's blades are susceptible to increased erosion.  Too cold, less power is developed while excess fuel gets wasted.

Comparing to other (real?) Temps...

CHTs have shown that probe type and location can add some unwanted variability to the data.  The ring probe under a spark plug is a horrible substitute for a pair of TCs occupying the same well.

OilT has 'acceptable' variations on probe location, volume of oil in the sump,  OAT and oil cooler status.

CarbT has a calibrated danger zone around the freezing point of water under the various conditions of the carb's Venturi.

EGT is a real temperature...

It just may take some additional hardware and extra effort to make it useful.  Fortunately, most Mooneys either came with or can be updated by adding the additional hardware for a couple of AMUs or so...

When Mike B says it isn't a 'real' temp.  He may not mean it isn't a real temp.  He is focusing the greater audience's attention, momentarily, on the next important piece of information related to EGT. A topic that many pilots have only glossed over while using the lean til rough, then enrich to 50° from that point.

How does that sound?

This is a PP's point of view.  I am not an avionics engineer...

Best regards,

-a-

[PTK]

Well, we know that CHT approaching or exceeding 400^o F is excessive. I never let mine go over 360ish or so with some variation depending on OAT. Can't we view excessive EGT similarly? Doesn't excessive EGT indicate an excessively hot combustion event from an excessive fuel:air ratio? It is an average temperature but isn't it nevertheless a meaningful temperature?

[Bob - S50]

As TJ said, the EGT you see is the average temperature of the EGT probe.  It spends 1/4 of the cycle bathed in hot gas (exhaust cycle) and 3/4 of the cycle with no airflow at all.  So it heats for a short time and then cools for a long time (relatively speaking).  So the temperature you see is really actually lower than the temperature of the gases exiting the engine and thus not 'real'.  Because the turbine inlet probe sees the exhaust from all cylinders, it is bathed in exhaust gas nearly continuously.  It will be closer to actual temperature and be 'real'.

As for the EGT getting too hot.  There are only two ways to make the gases hotter.  1).  Create a perfect mixture of fuel/air.  This occurs at peak EGT.  2).  Cause the peak cylinder pressure to occur closer to top dead center when there is less space above the piston.  This can happen if your magneto is timed wrong and firing too early.  That's one (main?) reason EGT drops as you go rich of peak.  The less than ideal mixture causes a slower burn in the cylinder which causes the peak pressure to occur further after top dead center.

If your timing is set correctly, you cannot make your EGT too high.  You can, however, make your cylinder peak pressure too high by having the magneto timing set too early.

[PTK]

9 minutes ago, Bob - S50 said:

...It spends 1/4 of the cycle bathed in hot gas (exhaust cycle) and 3/4 of the cycle with no airflow at all.  So it heats for a short time and then cools for a long time (relatively speaking).  So the temperature you see is really actually lower than the temperature of the gases exiting the engine and thus not 'real'. 

Ahha! This is makng more sense!

So |EGT| is not meaningful because it's a false value? It has no relationship to what just went on in the combustion chamber because the probe spent alot more time cooling down? 

But even so, it did start at a temperature which is directly related to the exhaust gas temperature the instant the exhaust valve opened. No?

 

[Cyril Gibb]

12 minutes ago, Bob - S50 said:

  The less than ideal mixture causes a slower burn in the cylinder which causes the peak pressure to occur further after top dead center.

To complete the thought, a richer mixture than peak (perfect stochiometric mixture) speeds up the flame front and a leaner mixture slows the flame front.  That's why I only use a LOP mixture when cruising at a low RPM.  A peak or ROP mixture at low RPM would create a max cylinder pressure too close to TDC.

The (average) EGT reading is totally irrelevant.  The number is affected by probe location, mixture, RPM, throttle position, etc.  The only important use is to determine peak EGT to allow you to set whatever ROP or LOP preference you have. 

[Bob - S50]

2 minutes ago, PTK said:

Ahha! This is makng more sense!

So |EGT| is not meaningful because it's a false value? It has no relationship to what just went on in the combustion chamber because the probe spent alot more time cooling down? 

But even so, it did start at a temperature which is directly related to the exhaust gas temperature the instant the exhaust valve opened. No?

 

It is still meaningful, it just isn't the same as the temperature reached inside the cylinder during combustion.  While it is indicative of what is happening, it isn't the actual temperature during combustion.

It is very meaningful in finding the correct fuel/air mixture.  Regardless of what your EGT reading is (1200F, 1400F, 1500F) when it peaks, you have the ideal mixture and the fastest possible combustion.  In theory, if is was a perfectly distributed mixture, you would have no left over oxygen or unburned fuel coming out of your engine.  However, the mixture is never ideally distributed so at peak EGT you have a little unburned fuel and a little unused oxygen coming out of your engine.  That's why peak power is just a little (50 - 100F) ROP.  That's what it takes to use up all the oxygen with a little fuel left over.  Similarly, that's why best economy occurs just a little LOP (30 -50F at cruise power settings) because that's what it takes to use up all the fuel with a little oxygen left over.

[Bob - S50]

7 minutes ago, Cyril Gibb said:

To complete the thought, a richer mixture than peak (perfect stochiometric mixture) speeds up the flame front and a leaner mixture slows the flame front.  That's why I only use a LOP mixture when cruising at a low RPM.  A peak or ROP mixture at low RPM would create a max cylinder pressure too close to TDC.

I don't think so.  The fastest flame front occurs at peak EGT.  Anything leaner OR richer slows down the process.  A lower RPM will increase cylinder pressure regardless of whether you are LOP or ROP.

Here's a good Pelican's Perch article from John Deakin: http://www.avweb.com/news/pelican/182084-1.html

And here is a quote from that article:

"Our POHs instruct us to use full-rich for takeoff. The extraordinarily rich mixture is required to assure that detonation does not occur. The conventional wisdom is that the purpose of the "excess" fuel is to cool the engine, but in fact its primary purpose is to slow the combustion rate and delay the PPP, which eliminates the risk of detonation by reducing the pressure peak. This does, in fact, result in cooler operation, but that's actually a second-order effect of the delayed PPP. (If we could just retard the ignition timing for takeoff, we wouldn't need to throw all that extra fuel at the problem.)"

The bold emphasis is mine.

[jlunseth]

These guys are right about what's going on, but I think the question you are asking is really a "purpose" question, in other words, what is the purpose of measuring EGT.

Start with the fact that temperature probes always measure and report their own temperature.  Now, in the case of a cylinder head probe, the probe is buried in metal and heats to the temperature of the surrounding metal, more or less.  The purpose of sticking a probe there is metallurgy - we don't want the cylinder metal to heat excessively because we know the metal becomes vulnerable to excessive wear and damage.  

The purpose of the EGT is to measure how far the mixture is from a stoichiometric mix.  A "stoichiometric mix" is the perfect mix where all of the gasoline and all of the oxygen are consumed during combustion.  It produces the highest temperature and also the highest pressure.  The EGT lets us find where that mix is (peak) and then go rich or lean of peak to moderate the ICH (internal cylinder head pressure) so we don't subject the cylinder to too much of a pounding.  

Its purpose is not to directly protect any metal from temperature damage, in other words, we are not worried about some piece of metal getting too hot, whether the exhaust tubes or the cylinders or the pistons or whatever.  That is what the CHT is for.  We are interested in the temperature of the exhaust gas itself, because that tells us whether we are burning a stoichiometric mixture or some other mixture, and once we have established what "peak" is, we can determine how many degrees cooler than "peak" the exhaust gas is at.  That gives us a "degrees ROP" or "degrees LOP" number.  

It is possible in conditions where cooling is very good, to have CHT's in a low safe zone, under 380 dF, but to have EGT's at peak and thus to be exposing the cylinders to maximum ICH.  Would not want that.  

EGT is also an indirect measurement of power output.  In other words, if you run the engine at peak and 50% power you will see a lower EGT than if you run it at peak and 100% power.  The problem with using EGT in this way is that there are too many variables for it to be useful.  OAT, altitude (how good the air is at cooling) will all have too large an effect, so we can't take the EGT's on one day, compare them to EGT's on another day, and say what power settings the engine was being run at because the variables have too much effect, and because that is not the purpose of EGT temp to begin with.  

So the EGT probe is reporting its own temperature to us.  Because of probe placement variations - one probe may be further away from the exhaust port than another and therefore at a different point in the exhaust flame - two cylinders can be burning exactly the same mixture but the probes report different temperatures.  We don't care what the absolute temperature is, because that is not the purpose of the measurement.  What we want to know, and the purpose of the measurement, is at what point in changing the mixture does that temperature peak and then start to cool again.  

That's what it is there for.  It is not there to measure the temp of any components, or the actual combustion temp in the cylinder, or anything of that nature.  Just peak, and degrees off peak.

[Cyril Gibb]

6 minutes ago, Bob - S50 said:

I don't think so.  The fastest flame front occurs at peak EGT.  Anything leaner OR richer slows down the process.  A lower RPM will increase cylinder pressure regardless of whether you are LOP or ROP.

Here's a good Pelican's Perch article from John Deakin: http://www.avweb.com/news/pelican/182084-1.html

And here is a quote from that article:

"Our POHs instruct us to use full-rich for takeoff. The extraordinarily rich mixture is required to assure that detonation does not occur. The conventional wisdom is that the purpose of the "excess" fuel is to cool the engine, but in fact its primary purpose is to slow the combustion rate and delay the PPP, which eliminates the risk of detonation by reducing the pressure peak. This does, in fact, result in cooler operation, but that's actually a second-order effect of the delayed PPP. (If we could just retard the ignition timing for takeoff, we wouldn't need to throw all that extra fuel at the problem.)"

The bold emphasis is mine.

Oops, sorry.  You are absolutely correct.  I should reread, slow down and think about my appends before hitting submit.

The essence of what I meant to say was that slowing the flame front by running LOP partially compensated for the higher pressure caused by a slower RPM.

[ArtVandelay]

i use the EGT to lean on a climb, I know my plane, I know what the EGT at peak is, so on climb after I've settle in (after flaps retracted, landing light off, handoff to ATC if IFR) I use the absolute value of EGT to lean to 150 degrees ROP, gives me plenty of margin, but improves engine power and fuel consumption...this is how I lean for high altitude airports as well.  Not sure how others handle high altitude takeoffs but my method seems to work well.

[carusoam]

Two or three examples of EGT being real and being used to protect equipment...

You guys have covered the normal psychology of EGTs pretty well.  The abnormal psychology can also be of interest.  

During the run-up, there is an EGT rise when a mag is shut down.  It's an example of mechanically messing with the flame front without changing the mixture.  The flame front is now blazing down the Exhaust tubes and touching the EGT probes.  The EGT starts approaching the flame temp of the fuel/oxygen mixture.

Great news: The real temperature of EGT, is indicating a real problem of a spark plug not working properly.

 

See if I can get JL to agree with me on this...

•  Unusually High EGTs can damage equipment...
• Blazing red exhaust pipes slowly change the structure of the pipes over time.  Original smooth surfaces appear to change to wavy surfaces as internal stresses of manufacturing are released.  Welds get eroded and muffler internals wear.
• Unusually high EGTs are very similar to the ship's TIT gauge being very high.  High EGTs lead to high TITs which leads to turbine erosion.  It is a real temperature that is related to the softening point of the metallurgy.

How did I do describing these issues?

Best regards,

-a-

 

[cnoe]

It is possible in conditions where cooling is very good, to have CHT's in a low safe zone, under 380 dF, but to have EGT's at peak and thus to be exposing the cylinders to maximum ICH.  Would not want that.

Great discussion guys, but I might argue that CHT loosely tracks internal cylinder pressure and running stochiometric (peak EGT) is fine at lower power settings (perhaps less than 65%). GAMI agrees with this.

When I'm at 10K and making ~55% I see no need in being 30 LOP as CHTs are already in the low 300s. I sometimes go to peak or very close to maximize power at a near optimal economy burn.

[carusoam]

CNOE,

At high altitude running at or close to peak becomes more of the norm for NA engines.

JL has the TC to contend with making LOP, ICPs, EGTs and CHTs more challenging. 

 

I always look look forward to input from JL and Ross on this topic.  They have the experience and writing skill to make it interesting.

Best regards,

-a-

[Shadrach]

7 hours ago, Bob - S50 said:

I don't think so.  The fastest flame front occurs at peak EGT.  Anything leaner OR richer slows down the process.  A lower RPM will increase cylinder pressure regardless of whether you are LOP or ROP.

Here's a good Pelican's Perch article from John Deakin: http://www.avweb.com/news/pelican/182084-1.html

And here is a quote from that article:

"Our POHs instruct us to use full-rich for takeoff. The extraordinarily rich mixture is required to assure that detonation does not occur. The conventional wisdom is that the purpose of the "excess" fuel is to cool the engine, but in fact its primary purpose is to slow the combustion rate and delay the PPP, which eliminates the risk of detonation by reducing the pressure peak. This does, in fact, result in cooler operation, but that's actually a second-order effect of the delayed PPP. (If we could just retard the ignition timing for takeoff, we wouldn't need to throw all that extra fuel at the problem.)"

The bold emphasis is mine.

Negative. The fastest flame front occurs at ~40ROP. This is where fuel is burned at the most rapid rate and ICPs are highest. Most complete combustion does not equal the most rapid combustion. This is why all other things being equal, 40ROP will generate the highest ICPs. My engine actually runs cool at peak.

[bradp]

Trying to wrap my noggin around flame front speed and engine timing; can you guys relate this back to mag timing on some of the IO-360's that had the option of going from 20-BTDC magneto timing to 25-BTDC?  Based on the above, the 5-deg timing advance would slow the flame front down.

What would this timing advance do to the peak pressure in the following situations?

1) delta-5deg adv:  RPM 2700 @  a) LOP 10 deg / peak / c) ROP 40 deg

2) delta-5deg adv:  RPM 2500  @  d) LOP 10 deg / e) peak / f) ROP 40 deg

3) delta-5deg adv:  RPM 2300  @  g) LOP 10 deg / h) peak / i) ROP 40 deg

 

[wishboneash]

5 hours ago, Shadrach said:

Negative. The fastest flame front occurs at ~40ROP. This is where fuel is burned at the most rapid rate and ICPs are highest. Most complete combustion does not equal the most rapid combustion. This is why all other things being equal, 40ROP will generate the highest ICPs. My engine actually runs cool at peak.

Isn't it then possible to corroborate this with CHT measurements at both peak EGT and at 40 deg ROP? Looking at the CHT and ICP curves for various engines they seem to be peak at the same temp (except they have different scales). So this would be a good way to determine when to run LOP or ROP at the lower altitudes and avoiding the red box?

[jetdriven]

5 hours ago, Shadrach said:

Negative. The fastest flame front occurs at ~40ROP. This is where fuel is burned at the most rapid rate and ICPs are highest. Most complete combustion does not equal the most rapid combustion. This is why all other things being equal, 40ROP will generate the highest ICPs. My engine actually runs cool at peak.

That's also the hottest exhaust valve temperature. 

[jetdriven]

36 minutes ago, wishboneash said:

Isn't it then possible to corroborate this with CHT measurements at both peak EGT and at 40 deg ROP? Looking at the CHT and ICP curves for various engines they seem to be peak at the same temp (except they have different scales). So this would be a good way to determine when to run LOP or ROP at the lower altitudes and avoiding the red box?

If you run less than 24" of MP, OR the fuel flow above 24" is less than 10.0 GPH you are already not in the red box. Keep CHT below 400 as a secondary measure. .  It's that easy. 

[Shadrach]

15 hours ago, PTK said:

I enjoy Mike Busch's seminars and have learned a ton and continue to learn from him. I have a hard time grasping this concept. He says that EGT isn't a real temperature. Can someone please explain this. I understand the variables of probe position, vlalve timing etc. but these don't change and gases coming out of the exhaust valve are at a certain temperature aren't they? If  we say the |EGT| is meaningless can't we say the same thing about CHT for example or OT?

 

To build on the answer to your original question.  One can generally say that the raw numbers do not matter because there not actual numbers.  It is true that the number spread from EGT to EGT is irrelevant.  APS and Busch have harped on this I think to deter people from being concerned about setting their engine for cruise and seeing numbers that look like this:

Cyl1 1468°

Cyl2 1436°

Cyl3 1533° 

Cyl4 1481°

There is no reason to try and bring those numbers closer together based on the raw numbers alone. If they all peaked at close to the same fuel flow, it matters not what the peak temps were.

However, there are assumptions that can be made it using the raw numbers, and I am pretty sure that Mike Busch and the APS guys would agree with this notion if asked in context.  

For instance, Full rich EGT on take off.  We know that a typical NA aero engine will not produce an EGT reading above about 1550° at the very high end of the spectrum.  Therefor, if you notice that you have an EGT in the mid 1400° range on a full rich take off, you can deduce that there is no way that that cylinder is in the desired 250-300° ROP range.  There will be those who argue that raw EGT numbers never matter. If however, you can deduce that a cylinder is running at less than 200° ROP it's probably best to have your aviation maintenance professional look into it. Understand that some of them may look at you cross-eyed when you tell them.

[Shadrach]

1 hour ago, wishboneash said:

Isn't it then possible to corroborate this with CHT measurements at both peak EGT and at 40 deg ROP? Looking at the CHT and ICP curves for various engines they seem to be peak at the same temp (except they have different scales). So this would be a good way to determine when to run LOP or ROP at the lower altitudes and avoiding the red box?

It is possible to use CHT readings to help determine optimal power settings, but one must be mindful that all things are not equal for every flight.  My engine loves low altitude, High Power, LOP operations.  On cold winter days, I can pull 30" of MP with the Ram air open at 2000msl.  I run LOP under those conditions, but I would be uncomfortable with CHTs above 340° simply because I know that I one of the main factors that determines CHT reading is the volume and temp of the cooling air.   ICPs that generate 350-380 in the dead of winter would likely generate CHTs into the 400s under more temperate conditions.

[wishboneash]

31 minutes ago, Shadrach said:

It is possible to use CHT readings to help determine optimal power settings, but one must be mindful that all things are not equal for every flight.  My engine loves low altitude, High Power, LOP operations.  On cold winter days, I can pull 30" of MP with the Ram air open at 2000msl.  I run LOP under those conditions, but I would be uncomfortable with CHTs above 340° simply because I know that I one of the main factors that determines CHT reading is the volume and temp of the cooling air.   ICPs that generate 350-380 in the dead of winter would likely generate CHTs into the 400s under more temperate conditions.

Yes. I intended to mention the OAT as a factor as well. Absolute CHT is not created equal as you stated. I usually reduce power with a combination of MP and RPM adjustments to below 65% and then it doesn't matter whether you are LOP or ROP at any altitude.

[Shadrach]

3 hours ago, bradp said:

Trying to wrap my noggin around flame front speed and engine timing; can you guys relate this back to mag timing on some of the IO-360's that had the option of going from 20-BTDC magneto timing to 25-BTDC?  Based on the above, the 5-deg timing advance would slow the flame front down.

What would this timing advance do to the peak pressure in the following situations?

1) delta-5deg adv:  RPM 2700 @  a) LOP 10 deg / peak / c) ROP 40 deg

2) delta-5deg adv:  RPM 2500  @  d) LOP 10 deg / e) peak / f) ROP 40 deg

3) delta-5deg adv:  RPM 2300  @  g) LOP 10 deg / h) peak / i) ROP 40 deg

 

Advancing the timeing does have an effect on the flame front, but that does not mean that it's slows it. I believe the net effect would be that it would typically advance peak pressure, which will typically reduce detonation margins and raise EGTs. FWIW, the IO360 A1A in my F model runs very cool with the timing @25BTDC. In fact in the winter it runs so cool (CHTs 275-325) depending on power.  I used to be concerned about lead scavenging, but it's never been an issue.

[jlunseth]

11 hours ago, carusoam said:

 

 

See if I can get JL to agree with me on this...

•  Unusually High EGTs can damage equipment...
• Blazing red exhaust pipes slowly change the structure of the pipes over time.  Original smooth surfaces appear to change to wavy surfaces as internal stresses of manufacturing are released.  Welds get eroded and muffler internals wear.
• Unusually high EGTs are very similar to the ship's TIT gauge being very high.  High EGTs lead to high TITs which leads to turbine erosion.  It is a real temperature that is related to the softening point of the metallurgy.

How did I do describing these issues?

Best regards,

-a-

 

I say yes to point 1, I don't know enough about pipe metallurgy to answer 2 but I will go along with what you say, but on number three I beg to differ a little.  EGT is a temperature that is "related" to the softening point of the metallurgy, but the relationship is not a very accurate one.  I think the question about whether EGT is a "real" temperature, goes to whether it measures the temperature of something other than itself, and it does not.  It measures the temp to which it (the probe) is heated by periodic puffs of hot burning gas.  TIT is interesting.  TIT is always higher than any of the EGT'S and the difference, in my engine, can vary from 50-125 degrees.  Being curious about this I have asked, and learned on this site and from some friends who design engines and boosting systems that there is a secondary event occuring in the exhaust system.  The exhaust gas, in other words, continues to burn in the exhaust system and it burns hotter than when it came out of the port, by quite a bit.  So EGT is really not a very good measure if you are looking to protect the pipes because the pipes are seeing significantly more heat than what your EGT(s) are telling you.  

I have run my engine now for a couple of hundred hours at LOP in cruise.  There is quite alot of variation in EGT between the cylinders.  To give you a general idea, the coolest EGT might be around 1490 and the hottest might be around 1550, while the TIT is brushing up against 1600.  I haven't seen any deterioration in the pipes.  There was some scaling of the tailpipe early on, but it has not changed in a couple of hundred hours.  The Bravo and Acclaim guys routinely run and even higher TITs.  But I guess what I am saying is that EGT is not a very good indication of the temp in the exhaust system, and it depends quite alot on which EGT you pick.  

The question I have heard raised about high EGT's is not the pipes though, it is the valves.  If you run LOP, EGT's will be about 100 degrees hotter than when ROP.  It stands to reason.  A good ROP setting in my engine is 125 ROP, and LOP I am about 20-30, so there is a rougly 100 degree difference.  One question that gets raised is whether the valves will have a shorter life because they are being exposed to hotter exhaust gases when LOP.  I haven't seen it in my engine but maybe I will when the engine is broken down in a couple of years for the overhaul.  Although I have heard the question raised I have never seen any evidence provided to answer it one way or the other.

APS is doing a Master Seminer in early June in Ada, for people who have already been through one of the live seminars.  I can't go, but maybe someone else can and will see if they can get an answer.

Edited April 1, 2016 by jlunseth