BrettKS

Seeking cool weather pilots

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With all these nifty devices for preheat I seem to remember that years ago some just used a 100 watt bulb in the bottom of the cowl with moving blankets on top and turned it on the night before Or am I hallucinating? 

Also. for all you "connected" guys maybe we need a thread (maybe sticky) showing all the ways you have figured out how to do this stuff (not just pre-heaters)(pictures, circuits and named devices and how to use them) for those of us still in the Luddite range on all of this. 

Not everyone is as "up to date" as some on all this stuff :-) :-)  Anything is easy if you know how :-)  Flying a 757 into CAT III weather was easy because I knew how (way back when). All this wifi, Alexa, connected TVs, etc not so much as time marches on and some of you young whippersnappers will find this out in the years to come  :-) :-)

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1 hour ago, cliffy said:

With all these nifty devices for preheat I seem to remember that years ago some just used a 100 watt bulb in the bottom of the cowl with moving blankets on top and turned it on the night before Or am I hallucinating? 

Funny that I just had a fellow MSer over for dinner last night and mentioned that I've used the light bulb in the past with good results.  The light bulb is actually less likely to cause condensation in the engine than the pan heater.  If you do use a bulb be sure it's the old fashioned incandescent type, and consider using a Thermocube to save a bit of electricity and extend the bulb's life.

https://www.walmart.com/ip/TC-3-Cold-Weather-Thermo-Cube-Thermostatically-Controlled-Outlet-On-at-35-Degrees-Off-at-45-Degrees/21154717?adid=22222222254365988468&wmlspartner=wmtlabs&wl0=b&wl1=g&wl2=c&wl3=392317297864&wl4=aud-430887228898:dsa-860780935364&wl5=9013543&wl6=92398430978&wl7=&wl8=&veh=sem&gclid=Cj0KCQiAiZPvBRDZARIsAORkq7dMIrTtLiGG8a4W1CVQp7bZ4VJ9un_3xnZKRLQFYYBCmvuudIzB4qwaAkcJEALw_wcB

 

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14 hours ago, takair said:

a Couple of other thoughts to consider regarding leaving engine heat on all the time (not facts, just thoughts)......with heat on, I would expect the residual oil to be more viscous....and drain to the sump faster than a cool engine, potentially leaving the cam and cylinder walls unprotected longer than cold oil. (?)  Also, I have wondered if seals might deteriorate faster if constantly heated.....may depend on where they are in proximity to the heat elements.

Funny you should mention this. I had a new cylinder installed in September and have been monitoring the oil level like an overweight fat guy watching a Wawa sub being made. It started getting colder in early November and I pre-heated a few times. What I noticed is that when I shut down the engine and look at the oil level the next day or two, it will remain at the same level. However, if I pre-heat for 6 or more hours, I will see as much as 0.25 quarts more on the stick. Wonder where this oil is heating up and moving down the engine from?

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1 hour ago, Marauder said:

Funny you should mention this. I had a new cylinder installed in September and have been monitoring the oil level like an overweight fat guy watching a Wawa sub being made. It started getting colder in early November and I pre-heated a few times. What I noticed is that when I shut down the engine and look at the oil level the next day or two, it will remain at the same level. However, if I pre-heat for 6 or more hours, I will see as much as 0.25 quarts more on the stick. Wonder where this oil is heating up and moving down the engine from?

Maybe this is just the thermal expansion of the oil?

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Or maybe its getting thin enough to drain out of all the overhead galleys  and filter? 

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I should have known MS-ers would have taken DIY stabs at this problem already. Thanks for enlightening me on the current solutions and enjoyed hearing about some alternative ways to get our Mooneys warm.

I have a similar mindset as carusoam.. while I know how to connect a relay to a cellular modem to AC mains, I don't think it's wise for me to do. Liability for starting an electrical fire using a non-UL listed AC device in my T-hangar that is connected to aircraft much more expensive than mine gives me reservations (would insurance even cover this?). I also wonder what kind of testing some of these Chinese devices have gone through.. but maybe they are UL listed?

I've actually used the commercially available IoT relay that was linked above. That way I can tinker with low voltage stuff and keep the heavy lifting in a) a separate box and b) someone else's product. Also as mentioned previously, I've used an embedded device with a cellular modem to drive a relay (we think alike!). The differences I've seen that set my method apart are: 1) LTE vs 2-3G networking -- 2G is nearly gone; I wonder what the support life-time of this cellular technology is; also better network coverage 2) A web app; SMS is old technology that is not as reliable and slower. I prefer to have a web-based portal that allows me to activate the switch among other features. 3) Web controls that make it "smarter"; turn on on this date if temp is < X, get history/status, set up schedules, overall just a bit more fine-tuned control. For the more nerdy folks, a RESTful API. 4) Possibly most importantly, a bit more affordable than the other commercial products out in the $300-500 range.

Total cost of the hardware would be about $100. Subscription/service cost would depend on how many use it in order to support the backend, but somewhere in the $5 to $10 per month range.

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5 hours ago, carusoam said:

Email from SwitchBox...

Came in a couple of days ago...

With the headline of upgrading from 2G to something more modern...

-a-

https://switchboxcontrol.com/the-switch-box

I don't see any info on their website yet. But presumably still using SMS commands / phone calls, still quite expensive, relies on keeping credits loaded on a prepaid plan and counting your texts.

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I suspect the light bulb thing works great in places where it doesn't get really cold.  In places where it does you need some kind engine heater, or a heated hangar.  Oh that's right, Mooneyspace inmates wouldn't use one of those.  Causes corrosion doncha know?

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17 hours ago, cliffy said:

Or maybe its getting thin enough to drain out of all the overhead galleys  and filter? 

Would it not have drained while still warm from the previous flight?  Genuinely curious, not doubting.  My first thought was same as @Jim F's , "thermal expansion", but that would be around 0.00039 per degree F.  Assuming 8 qts, to get another 0.25qt it would be what, 1/32 of the total volume, so just over 3%, so heated up by 80F?

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Water causes corrosion, warmer air holds more water. And yes, higher temperatures accelerate the rate of corrosion.  It doesn't "cause" it per se.

A dry engine wont corrode as much or at all, depending on the water vapor amount inside it.  Heating an engine to drive the Rh down prevents precipitation inside the engine, but it also increases the grams of water per cubic volume, in an absolute sense. .  More water vapor, more temperature. Worse, not better.

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4 hours ago, tmo said:

Would it not have drained while still warm from the previous flight?  Genuinely curious, not doubting.  My first thought was same as @Jim F's , "thermal expansion", but that would be around 0.00039 per degree F.  Assuming 8 qts, to get another 0.25qt it would be what, 1/32 of the total volume, so just over 3%, so heated up by 80F?

What made me think of it is that I had the cylinders off for a few weeks and I checked the cam every couple of days to make sure it was covered in oil and not getting rust. When a pulled the jugs about a week after the previous flight, there was thick oil dripping (cold hangar) off the cam lobes. Over the next couple of weeks, there was certainly less, but still not dry. I did have cam guard, so maybe that is part of the magic. Either way, I suspect that a warm cam would shed that oil faster and then be exposed to the humidity that may go with the warmed up compartment. Would be an interesting test. I suppose one could do it with sheets of steel. Add oil, heat one and don’t hear the other and see which rusts first. I suspect the heated steel will lose the oil film faster. Add to that the higher water content discussed above.....

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When doing tests...

The material is the most important part of testing...

Different steels rust in different environments...

So using real cam parts or real cylinders to do the test makes the most sense...

 

I once worked in a lab that got a really good temperature and RH control system...

Over an extended period of a few days the lab was closed for a holiday.... some automatic building control turned the controls off...

Anything that was going to rust, got a nice coating of oxidation on it...

It isn’t hard to accidentally get 90°F and 90%RH if you aren’t watching very closely.

 

The engine case has lots of moisture available from the by-products of burning gasoline... the owner adds the heat....

+1 moisture & heat are bad for metal parts...

 

PP thoughts only, not a metallurgist...

Best regards,

-a-

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9 hours ago, steingar said:

Only on Mooneyspace would folks decry a heated hangar.  Gotta love this place.

You’re not addressing the points I made above. 

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A few years ago I was frustrated by all of the opinion on this subject but lack of real data. I built a device to gather the data on my own. I've posted on this here before, so for some this is old news. I used a PIC microcontroller along with a cellular modem chip and some temperature/humidity sensors. 

The executive summary, in my sample of 2 engines, I found that increasing temperature leads to lower measured RH inside the engine.

I also did some internet searching, finding that RH < 30% results in low corrosion and > 60% high corrosion. So my goal is 30% or less RH.

Here is the theory. Corrosion is a micro-battery on the surface of the metal. The moisture combines with impurities (blow-by, acid, etc.) and creates a micro-cell which creates the corrosion. The key concept is this: If the moisture in the engine is evaporated into the air in the engine, it is not on the surface of the metal and therefore not available to cause corrosion. Water in the air is not a problem. Water on the surface of your steel engine parts is the problem.

There are two possible scenarios in the engine:

1) Saturated environment. Envision a bowl half full of water with plastic wrap sealing the top of the bowl. The air is saturated, always 100% humidity, no matter what temperature. This would be bad.

2) Un-saturated environment. Envision a bowl of water with a few drops in the bottom at 33 degrees F. As the temperature warms, the water evaporates. RH goes down as temperature goes up.

Because my measurements show a decreasing RH as temperature rises, I believe that there is not enough moisture in the engine to create a saturated environment. Therefore, a bit warmer is better, reducing RH and trapping the moisture harmlessly in the air and not available for corrosion. I programmed my device to maintain a steady 90 degrees F regardless of external temperature. I was looking for the lowest temperature that gives a good RH result. 

This is only on a sample of two engines and in two locations. I had a J model for 5 years and 2.5 years ago traded that in for  K model. I have used this device both at KRHV and KTRK, both in California and not terribly humid. I have not tested this in a high humidity environment like the south.

Here is a thought on the light bulb technique. I have a Reiff, 100W on 6 cylinders and 100W on the pan. With 700 watts heat I can get 80 degrees F rise over ambient at 100% power, with a cowl blanket. Simple math says a 100W light bulb would be lucky to get 15 degree rise. Hard to see how this is enough power in a cold environment.

Here is the current graph. Humidity in the engine is a tad high, but look at the external humidity. We've had a week worth of constant rain here, so things are a bit soggy. PWM (Pulse Width Modulation) is the % power, averaging around 50% or so for this period.

Larry

 

ChartImg.png.26af6d5fa3d393fba580d9a0b3bacbd5.png

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On 12/1/2019 at 6:25 PM, BrettKS said:

I had an idea for a device and ended up prototyping a few, looking for testers. The device is an internet-connected (cellular LTE) AC switch with a web app control. The idea is to plug in my engine preheater and toggle the switch from my phone several hours prior to flight. I am of the mindset that it's not ideal to keep the engine preheater on 24/7, and like I imagine most pilots, my hangar does not have wifi for me to use a readily available plug solution.

Anyways, I am looking for a few owners who have a similar issue and would use it regularly to give me feedback. If you're interested, please send me a PM with 1)your name, 2) location where you hangar your aircraft, and 3)on average how many months per year you use your preheater.

 

Edit: Comparison from devices mentioned below:

 

Something like this?

Have it in my hanger today Run engine heater an small space heater under belly to keep things un-Frozen in the cabin.

With a Wifi hotspot an app on your phone, have total control of turning things On/Off in my hanger from anywhere. 
 

This switch box is homemade by May hanger neighbor. He has a little less than $80 invested an a few hours of his time.

Its a very nice luxury to have, no 8 mile drives to the airport to plug in the night before.

Also, Via the cell app I can select a certain Channel(120v plug) to activate at a pre-determined time, an cutoff the same way.

F7F692E9-F1D6-40A1-BADC-510586534292.png

627C97A5-68B2-4E4D-ACCC-358D9C481D0A.png

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@larryb - have you posted details of your project?  If you did, I missed them, can you please point me to them?  If not, are you willing to write the setup up and publish, so less creative people like me can try and imitate?  Pretty please? :)

edit- by details I mean schematics / code / etc, not the resulting graphs.

Edited by tmo

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Thoughts on the Reiff and 100 w bulb-

Nice engineering approach to the problem BTW!

Granted 700 w is more power than 100 w.

Granted you can get 80 degree rise above ambient w 700 w

But what do we really need and for what?

The 100 w bulb was used to preheat enough to get started in the morning. 

Do we need an 80 degree rise to do that? 

Maybe 30 degrees would do in 20 F weather ? And maybe a 100 w bulb would do that?

The 100 w bulb may not be enough in -20 F weather to do the job and 700 w might be needed.

Again, what is the desired end point and what is the starting point (energy in to accomplish energy out) and what is needed to get there?

A question or two-

Do we know if the temp rise between 100 w and 700 w is linear? Or could there be some curve to the temp rise?

Could 100 w bring up the temp 30 degrees (at a start of 20 F) and hold it there and the temp rise of 700 w go to 100 degrees (20+80)?

Is a stopping point of 50 F good enough to accomplish the job in 20 F weather?

Would 40 F be good enough to start in 10 F weather? (assuming the heating is linear in the 100 W input for the starting point)

Will the 700 w always give an 80 degree rise no matter what the starting point is?

Again, what is the problem and what will just solve the problem? 

Now, if you want to talk long term storage and desired RH over the long term then a different set of numbers might be needed

Not saying anyone is wrong, just perambulating in the mind. 

 

 

 

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5 hours ago, Cody Stallings said:

Something like this?

Have it in my hanger today Run engine heater an small space heater under belly to keep things un-Frozen in the cabin.

With a Wifi hotspot an app on your phone, have total control of turning things On/Off in my hanger from anywhere. 
 

This switch box is homemade by May hanger neighbor. He has a little less than $80 invested an a few hours of his time.

Its a very nice luxury to have, no 8 mile drives to the airport to plug in the night before.

Also, Via the cell app I can select a certain Channel(120v plug) to activate at a pre-determined time, an cutoff the same way.

F7F692E9-F1D6-40A1-BADC-510586534292.png

627C97A5-68B2-4E4D-ACCC-358D9C481D0A.png

Awesome! A few questions:

- You mention wifi hotspot from phone; do you leave a phone in the hnagar with wifi hotspot activated at all times?
- If so, why not just use a commercially available product like the $5 smart plugs from amazon ($10 if you want two channels) that give you a wifi app for control?
- Also, my concern with DIY projects like these are they come with some liability for connecting home-made electronis to AC mains. Typically these products would require testing before being UL listed.

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Yes it’s what’s referred to as a HotSpot so I’m told.

Little black box from Verizon with a digital screen to show status an password.

I understand your concerns for testing, but it has had a lot of actual real world testing an has worked flawlessly. 
 

Reason I go this route is:

There are a few hanger neighbors that link up to this thing got various reason, an I also use it for monitoring the well-being of my assets. We have some airport commissioners that have demanded they have spare keys to all hangers, an they have been witnessed going in hangers at night to “check on peoples planes”.

Not anymore!!

FBA6685F-F92E-4818-A024-17BF79E37346.png

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2 hours ago, cliffy said:

Thoughts on the Reiff and 100 w bulb-

Nice engineering approach to the problem BTW!

Granted 700 w is more power than 100 w.

Granted you can get 80 degree rise above ambient w 700 w

But what do we really need and for what?

The 100 w bulb was used to preheat enough to get started in the morning. 

Do we need an 80 degree rise to do that? 

Maybe 30 degrees would do in 20 F weather ? And maybe a 100 w bulb would do that?

The 100 w bulb may not be enough in -20 F weather to do the job and 700 w might be needed.

Again, what is the desired end point and what is the starting point (energy in to accomplish energy out) and what is needed to get there?

A question or two-

Do we know if the temp rise between 100 w and 700 w is linear? Or could there be some curve to the temp rise?

Could 100 w bring up the temp 30 degrees (at a start of 20 F) and hold it there and the temp rise of 700 w go to 100 degrees (20+80)?

Is a stopping point of 50 F good enough to accomplish the job in 20 F weather?

Would 40 F be good enough to start in 10 F weather? (assuming the heating is linear in the 100 W input for the starting point)

Will the 700 w always give an 80 degree rise no matter what the starting point is?

Again, what is the problem and what will just solve the problem? 

Now, if you want to talk long term storage and desired RH over the long term then a different set of numbers might be needed

Not saying anyone is wrong, just perambulating in the mind. 

 

Temperature rise is linear with power and is independent of the starting point.

So the specific math to translate my result to a 100W bulb would be (80/700)  * 100 = 11 degrees. Insulation makes a big difference. I have an old quilt draped over the cowl. Without the quilt I get half of the rise compared to with the quilt. 80 degrees rise is with the quilt. More/better insulation will give you a better result.

I think you would want to get 40 degrees minimum for engine start and reasonable oil viscosity. At 20 degrees ambient 200W bulb and a quilt will get you that.

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3 hours ago, tmo said:

@larryb - have you posted details of your project?  If you did, I missed them, can you please point me to them?  If not, are you willing to write the setup up and publish, so less creative people like me can try and imitate?  Pretty please? :)

edit- by details I mean schematics / code / etc, not the resulting graphs.

Sorry, no. It's pretty complicated and very little is available off the shelf. It would be a huge effort on my part just to document it. The microcontroller is on a custom designed circuit board that I had previously used for home automation. The cellular modem board is off the shelf, and the same one used in many of the cell switches out there. There is C code for the microcontroller for both the cellular communication and the heater thermostat PWM function. Then there are two pieces of server code running on a windows box. The first is a "listener" program that listens on the internet for data from the microcontroller and saves the data on the server. Then there is a web server program that creates the graphs for the browser. Those were creatd with Microsoft Visual Studio and run on a Windows IIS server on a box in my closet.

But I don't think much of this is necessary. If you just want to keep the engine at a steady temperature like I do, you can leverage one of the many PID temperature controllers available on Amazon. PID is the control algorithm used. They rapidly turn on and off the heater element to achieve a very steady target temperature. The ratio of ON to OFF time is what determines the power level.

I have not personally used the device below, but it is of the type I would consider.

https://www.amazon.com/Inkbird-Temperature-Controllers-Thermostat-ITC-106VH/dp/B01N1ZUGUZ/ref=sr_1_1_sspa?keywords=pid+controller&qid=1575470406&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExNjZMTjk0RE1QOTBEJmVuY3J5cHRlZElkPUEwMjY1NDk0QzlLM0FQTTFWRzlXJmVuY3J5cHRlZEFkSWQ9QTAyMzM0NDE1UFM2NDlXOFBEU1gmd2lkZ2V0TmFtZT1zcF9hdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl

If you don't care about temperature swings then you can use something like this. 

https://www.amazon.com/Farm-Innovators-TC-3-Thermostatically-Controlled/dp/B0006U2HD2/ref=sr_1_2?keywords=cube+thermostat&qid=1575471316&sr=8-2

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Does everything you possibly can need, with a $10/mo cell charge. Commercial solution, free upgrades, extensible to include cameras, etc. I love DIY solutions, but why reinvent the wheel? :)

 

 

 

Screenshot 2019-12-04 10.26.13.png

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Screenshot 2019-12-04 10.28.12.png

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