Here’s my take on the subject.
If the engine has been running for awhile, the exhaust pipes will be quite hot and will remain hot even after the engine has been shut down. Until they cool down, they will show the heat blur. It sems correct to me that the heat blur will be seen on the Spartan for awhile until the pipes cool down.
If this was the intention of the developer, it’s a nice little touch, along with many other small touches.
The more I fly this, the more I enjoy it.
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That’s where you’re misunderstanding the heat blur. Yes, absolutely, the exhaust pipes will be hot for a while after the engine quits. But the pipes do not create the heat blur. What creates the blur is hot air – air that is less dense than the surrounding ambient atmosphere, and therefore has a different refraction index than the ambient air. Since the exhaust plume is not homogenous, and is also in motion, the light waves passing through it refract multiple times before coming out the other side. Add up those zillion waves passing through and interacting, and you get a wavy look. That’s the heat blur.
When the engine is off, the pipes are hot and are heating up the air around them – which RISES because it is less dense than the ambient air. That’s how hot air balloons work, after all. So when the engine is off, if there’s a heat blur at all, it’s ABOVE the engine, and the residual engine heat itself transmitted through the cowling is also adding to it – in the same way that you can see a “heat blur” effect on your hood (bonnet for the UKers) on a really, really hot day when you’re sitting behind the wheel. There is no hot exhaust flying at 100mph or so out of the pipes to push that pipe-heated air downwards, against its natural inclination to rise, and form that bubble of blur below the exhaust. So pipe-heated air with the engine off physically cannot go there, unless the ambient air is hotter than the heated air coming off the pipes (in which case it would be more dense, and sink). It has to rise. (If the engine had some sort of blower hooked into the exhaust system to help keep the system temperature low, then there could be a heat plume under the plane post-flight. But this engine doesn’t have anything like that, and I actually don’t know if ANY engines have anything like that…)
I totally get that you like signs that the engine has just been running – I agree, it’s immersive! – but this isn’t the way to do it. The heat blur with the engine off is identical to the heat blur with the engine on, and that is thermodynamically impossible. If it weren’t, then every other aircraft in the sim is modeled wrong, as every engine with an exhaust pipe would be pluming post-flight.
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I’m really loving this plane so far but the radio stack being all out of shape really bothers me. Especially with the blank/messed up space in the GPS and radio panels. Since there’s not enough room to have them all the correct size and scale could the transponder be moved down to the lower right?
Dave R44
Thank you for the explanation. It makes sense.
Hopefully in another update, we’ll get exhaust smoke on startup.
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Smoke would be awesome. My understanding is that these P&W radials were bigtime smokers when they started. (I’ve never seen one starting up live and in person though.)
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I am not a physicist nor an engine mechanic, but I’ll play the role of devil’s advocate to better understand what is happening here.
Hot air rises, but heat radiates in all directions. The heat of the bottom of the cowling and exhaust pipes radiates into the surrounding air, which in this case, is under the engine. That heated air should now show a “blur”. The heated air, unable to rise due to the barrier that is the fuselage itself, will move laterally in all directions until it is able to rise. So in my understanding, a moving blurry mass of air under the engine, as is modeled here, is correct.
I will have to get into the sim again and look, but if the engine-off blur is moving at the same speed as the engine-on blur, that would be a mistake. However, you might expect to see some movement, even in the absence of an exhaustive force. The air in the upper parts of the exhaust will be extra hot and will likely be forced out the exhaust pipes, even though they travel downwards.
Just to discuss the car example, the reason we see heat blur on the hood is because we are physically above the hood. But heat blur will be happening under the engine as well, and we could see it if we wanted to get under the car and had the right lighting conditions.
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I love the look and feel of the Spartan, but I have a couple issues: one is the AP, which I’ll talk about more after I fly and test it more; the other is the look of the gauges.
I like the reflections of the gauges, but overall there are some strange quality issues. The main one for me is with the CDI, the needle gets really faint, thin and fluttery when you move it with the course knob. It really looks awful. Plus there is no center top notch or arrow to help align it to the direction you want, so it’s a lot of guess work.
Is anyone else seeing this or could I have some mod conflict?
After reading these thoughts and watching the heat blur on the plane again, it seems like the answer to this would be to leave the amount of blur as it is when viewing the plane while it is in the air. When on the ground and the engine is shut down, reduce the heat blur so it only shows for a few inches around the exhaust pipes.
I now agree that the blur spreading back about a foot while the plane is on the ground doesn’t look right.
I seem to remember seeing this msfs plane with a full cover over it while parked, is there a clickspot somewhere in the cockpit that will show / hide the cover?
You’re mostly right! The one thing you’re missing is the fact that changes the whole equation: air is a TERRIBLE conductor of heat. One of the worst, if not the worst, on Earth. (The only poorer conductors of heat that I can think of are styrofoam, and a complete vacuum.)
There are two things that are moving heat here: the hot pipe (a solid), and the exhaust gas (a fluid). Each transfers its heat differently – the exhaust transfers its heat primarily via convection, because it’s a fluid passing through/into another fluid. The pipe, a solid, transfers primarily (as you noted!) through radiation – it glows in infrared (or visible light if it’s hot enough) and thereby gets rid of its heat by energizing photons. The pipe - as opposed to the gas stream – heats the air either by having those photons collide with air molecules, or by physical transfer (at the atomic level) when air molecules contact the surface of the pipe.
Somewhat confusingly, the easier a substance is to heat, the worse it is as a heat conductor. Air is super easy to heat, because its atoms/molecules are already moving pretty fast, and it doesn’t take much of a push to get them to move much faster, as they have plenty of room to zoom away at their higher energy speed (this is oversimplified, but good enough for government work). Water, on the other hand, is very difficult to heat, because it’s denser and has more molecules closer together to each other than air, and those molecules can slip around each other easily. So it takes a bunch of photons before that water molecule will have enough oomph to actually move fast enough to push its way past its neighbors. Water is therefore a fantastic conductor of heat, as it takes a lot of heat to raise the temperature (i.e. the energy) of a given volume of water even a little bit. One way to think of it – picture the thing giving up its energy as a buffet bar at a casino. Air is a bunch of supermodels – they each take one carrot stick, and then leave. Bad conductor of food! Water is me: 500 pounds of food on two trays later, the casino is bankrupt and the chef is a quivering wreck – but more importantly, the buffet is empty. Great conductor of food!
So the cooling post-shutdown pipe will be heating the air around it, but it will be doing so very inefficiently and won’t be transferring a ton of its heat to the air. The air that is heated will convect its energy away; it will rise and be replaced by cooler air, which will maybe get heated up a bit, etc. But the heated air will always rise. If you encased the cooling pipe in a perfectly insulated case with a pipe facing down… you still wouldn’t get a plume coming out of that pipe. The heat would be transferred into the air, which would rise, and the cooler air from the top of the container would sink and be heated, and eventually you’d get an equilibrium temperature inside the container. To get something to come out of it, you would either need the air’s temperature to rise far enough that its volume increased (because pressure would be constant because the pipe at the bottom is open to the air – ideal gas law FTW!) to the point where the initial container air “grew” enough to start spilling out of the pipe, or you’d need to be adding air to the container somehow (maybe a blower) to increase the air pressure inside of it, forcing air out of the pipe.
The 7W’s post-shutdown plume is identical to the active engine plume. That just can’t happen. To the extent the pipe is heating the air enough to create a visible convective column of hot air, it would be pretty small, and would be rising up the sides of the engine cowling.
Believe it or not, given some time and a good computer software suite and someone who actually had decent knowledge of physical equations, you could mathematically model exactly what you’d see when the engine stops as far as possible heat blurs from the exhaust pipes. It would be excruciating to do, as it would involve fluid statics and dynamics, optics, and the various heat transfer methods… but it’s theoretically possible. This is, more or less, the sort of thing that the sim’s computational fluid dynamics module is doing, just with airflow instead of convective heat transfer. But it’s fundamentally the same basic analysis – how a fluid and a solid interact.
End of lecture! Turn your papers in by next Friday. 
I should add that I love the 7W and the inappropriate heat blur in no way changes that.
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Just adding a bugs that hopefully the developer will see and take care of. May have been listed by others above.
Can’t see the landing lights from the external camera but they are visible in the drone camera.
Strobes CB on the left side is really a General Panel CB.
Nav lights are still visible in the external view even if the CB is pulled. But are extinguished in drone view.
When flying an ILS, once it locks onto the LOC, the plane starts swaying left and right to stay on the LOC.
NAV lights are on by default at cold and dark.
Pitot switch is on by default at cold and dark and toggles opposite to my Bravo switch (which works correctly on other planes). So I wonder if pitot heat is actually on when the switch is on.
Despite this being on SimMarket, I went ahead and bought it. It’s a nice plane to fly! I encountered a couple strange behaviors though.
Fuel economy seems to be WAY too good. I burned only 4% flying 300 NM from San Francisco to LA. A two hour flight of 300 NM should’ve burned 30% according to the 6 hr endurance/1,000 NM range figures.
I also encountered an error where the throttle, prop, and mixture levers seemed to stop actually changing engine performance. The levers in the virtual cocpit were responding to my HOTAS inputs, but RPMs, manifold pressure, and the mixture wouldn’t actually change. The gauges reflected that. Out of nowhere, the engine started responding to inputs again normally.
It’s a pretty nice addon for $21. Hopefully its quirks get ironed out.
Yeah, it seems a little too efficient to me as well. I did s little half-hour hop running fairly hard, and I think I burned all of 3 gallons or so. Should have been twice that, I think.
Well, I fixed the voice issue, but darned if I know how. Troubleshooting/fix steps:
- Move entire contents of Community folder to another location, then add Spartan back in.
- Start sim and test - have male voice with ATC.
- Move rest of Community folder back into place.
- Restart sim and test.
- Expect female voice.
- NOPE! Now I get the male voice like normal.
Logically, this shouldn’t have worked, but like so many other things in Windows, it just did. 
I’m off to have a bottle of liquid bread…
I’m sorry, what’s a CB?
(use of undefined acronyms is acrimonious 
)
Circuit breaker.
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By cleaning out the Community folder, flying the plane, then moving stuff back in, you moved the Spartan to the front of the list, so another mod might have taken over what pilot you are using. It’s possible the Spartan aircraft.cfg file doesn’t have a [PILOT] section, so was somehow unitialized? Who knows?
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To fix the Spartan, check the aircraft.cfg file. There is a [PILOT] section, that should look like
[PILOT]
pilot ="Pilot_Male_Casual"
copilot ="Pilot_Female_Casual"
instructor ="Pilot_Male_Casual"
pilot_default_animation ="Idle1_PosePropeller","","","","","","","","","","","","","","",""
copilot_default_animation ="Idle2_PosePropeller","","","","","","","","","","","","","","",""
pilot_attach_node="PILOT_0"
copilot_attach_node="PILOT_1"
The "pilot = " values in the aircraft.cfg file are supposed to be overwritten by whatever you have set for defaults. Might want to check your defaults and see who you have set by default for your pilot.
This is from the 7W’s config file:
[PILOT]
pilot = "Pilot_Male_Casual"
copilot = "Pilot_Male_Casual"
instructor = "Pilot_Female_Casual"
pilot_default_animation ="Idle1_PosePropeller"
copilot_default_animation = "Idle2_PosePropeller"
pilot_attach_node = "PILOT_0"
copilot_attach_node = "PILOT_NULL"
Don’t know if that looks unusual or anything… I use a female co-pilot, and I never had the same problem with the sound, so I can’t help explain this…
PILOT_NULL looks weird as a position. Would normally be “PILOT_1” or “Copilot”. I wonder if that was confusing whatever processes that section of the aircraft.cfg? I could see it throwing up its hands and causing issues over something like that… You can search the .gltf files in the model directory to see if PILOT_NULL exists as a position. If so, then it’s correct.
There are only two .gltf files in the model directory - an EXT_LOD00 and INT_LOT00. I assume any pilot nodes would be in the INT_LOT00 file if they were anywhere. Did a quick search and didn’t see anything. So maybe that is the issue…
Also, I think I’ve been spending way too much time futzing around in .cfg files this week…
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