Page 7 of 12 FirstFirst 1 2 3 4 5 6 7 8 9 10 11 12 LastLast
Results 91 to 105 of 169

Thread: Cabin Heat, Water Cooled Engines - Which Way is Best and Why?

  1. #91
    Registered User
    Join Date
    Jul 2014
    Location
    Rochester, NY, USA
    Posts
    2,196
    Likes (Given)
    33
    Likes (Received)
    859

    Re: Cabin Heat, Water Cooled Engines - Which Way is Best and Why?

    Combine autocorrect and the desire to use as few words as.

  2. Likes wsimpso1 liked this post
  3. #92
    Registered User Dan Thomas's Avatar
    Join Date
    Sep 2008
    Posts
    4,658
    Likes (Given)
    207
    Likes (Received)
    1938

    Re: Cabin Heat, Water Cooled Engines - Which Way is Best and Why?

    Quote Originally Posted by Toobuilder View Post

    One other thing to consider. I agree that the risk of failure is pretty minimal for either a wet system or a dry system, but that is only one side of the risk analysis process. There is also the severety of failure. And to me, this bears strong consideration. Even a small leak in your "wet" defrost ductwork is going to steam up your windshield in a split second. Unlike with a dry system, windscreen obfuscation will happen in summer or winter and is not going to be cleared with a towel. So with the possibility of failure low, and the severity of failure high, you are looking at an overall risk score of "moderate" every time you fly.
    In my safety training we used a matrix like this to assess risk. I bet some others here are familiar with it.

    Click image for larger version. 

Name:	Risk-Matrix-1024x550-1024x550.jpg 
Views:	18 
Size:	52.6 KB 
ID:	78482

    If you run the liquid-coolant heating system through the matrix, you also have to run the exhaust-type heating and electrical heating through it as well. Knowing what I've found with the exhaust-type heaters, and the propensity of electrical systems to fail, they too present a loss-of-heat risk along with either CO poisoning or electrical fire. Alternator failures are far too common, for instance, for various reasons.

  4. Likes Topaz liked this post
  5. #93
    Registered User Toobuilder's Avatar
    Join Date
    Jan 2010
    Location
    Mojave, Ca
    Posts
    4,160
    Likes (Given)
    416
    Likes (Received)
    2894

    Re: Cabin Heat, Water Cooled Engines - Which Way is Best and Why?

    Yep, very familiar with that style matrix.

    Two comments off the top:

    Malfuntion of a liquid system (a leak) can create windscreen obfuscation that will remain until on the ground or mechanically isolated. Mechanical isolation adds weight for no other purpose than to contain a failure. Thats a bad trade. Electrcal failure means the system will no longer work, but will not make it worse either.

    Alternator failure is already an accepted/properly mitigated event in Bills bird. He's already completely electrically dependant to keep the engine turning. A bigger alternator is not going to shift that risk one way or the other.

  6. #94
    Registered User rv6ejguy's Avatar
    Join Date
    Jun 2012
    Location
    Calgary, Alberta, Canada
    Posts
    3,325
    Likes (Given)
    2375
    Likes (Received)
    2351

    Re: Cabin Heat, Water Cooled Engines - Which Way is Best and Why?

    I have never owned a modern GM car but it appears lots of others in the automotive world don't turn on the a/c when the defog switch is on.
    Ross Farnham
    Racetech Inc.
    16 years and 428.6 hours on Subaru Turbo powered RV6A
    "The world is changed by your example, not by your opinion" Paulo Coelho
    http://www.sdsefi.com/aircraft.html




  7. #95
    Registered User wsimpso1's Avatar
    Join Date
    Oct 2003
    Location
    Saline Michigan
    Posts
    5,269
    Likes (Given)
    1932
    Likes (Received)
    2600

    Re: Cabin Heat, Water Cooled Engines - Which Way is Best and Why?

    Quote Originally Posted by Toobuilder View Post
    One other thing to consider. I agree that the risk of failure is pretty minimal for either a wet system or a dry system, but that is only one side of the risk analysis process. There is also the severety of failure. And to me, this bears strong consideration. Even a small leak in your "wet" defrost ductwork is going to steam up your windshield in a split second. Unlike with a dry system, windscreen obfuscation will happen in summer or winter and is not going to be cleared with a towel. So with the possibility of failure low, and the severity of failure high, you are looking at an overall risk score of "moderate" every time you fly.

    Not trying to steer the decision, Just food for thought.
    That was one of the reasons I was asking in the OP about using the oil cooler as a heater core. Gotta have an oil cooler someplace, maybe they are less likely to leak...

    Is there something to be thought about on using oil cooler (and engine oil) for cabin heat?

    Is there something to be thought about in using an oil cooler with glycol-water for cabin heat?

    Oh, and I am trying to get people to try to steer the decision...

    Billski
    Billski's opinions expressed here are available free and may be worth the money you paid for them. Understand that they are based upon a successful combination of education and a lifetime of experience using that education, but I can not know everything about your circumstances. Your choices are yours alone, and you must be the final judge on what you do. No whining...

  8. #96
    Registered User Dan Thomas's Avatar
    Join Date
    Sep 2008
    Posts
    4,658
    Likes (Given)
    207
    Likes (Received)
    1938

    Re: Cabin Heat, Water Cooled Engines - Which Way is Best and Why?

    Quote Originally Posted by rv6ejguy View Post
    I have never owned a modern GM car but it appears lots of others in the automotive world don't turn on the a/c when the defog switch is on.
    My Ford Ranger and Hyundai Sonata both use the AC with defrost. My '89 Ford F150 did, too, as well as the three GM vehicles I owned ('91 Chev S-10, '81 Pontiac Parisienne and 2001 Cavalier). The only vehicle I have owned in the last 30 years that didn't was the 1951 International pickup I restored. It didn't even take in outside air for the heater. Just recycled the interior air so that one had to roll the window down for defrost. Lots of fun in an Alberta winter.

  9. #97
    Registered User Dan Thomas's Avatar
    Join Date
    Sep 2008
    Posts
    4,658
    Likes (Given)
    207
    Likes (Received)
    1938

    Re: Cabin Heat, Water Cooled Engines - Which Way is Best and Why?

    Quote Originally Posted by wsimpso1 View Post
    That was one of the reasons I was asking in the OP about using the oil cooler as a heater core. Gotta have an oil cooler someplace, maybe they are less likely to leak...

    Is there something to be thought about on using oil cooler (and engine oil) for cabin heat?

    Is there something to be thought about in using an oil cooler with glycol-water for cabin heat?
    An oil cooler is much stronger and very unlikely to leak, but they're designed for lower flow volumes so you might need a big one. And a new one would be wise; they gradually get varnished up inside, insulating the liquid from the metal and reducing their heat transfer. I once had a cooler that I simply couldn't get cleaned inside and the engine ran hot. The only solution that worked was a new cooler. Nothing else helped. This was on a factory overhauled Lycoming engine. Took me a week or so to figure it out. The cooler wasn't plugged up or anything; fluid went through it fine.

  10. #98
    Registered User rv6ejguy's Avatar
    Join Date
    Jun 2012
    Location
    Calgary, Alberta, Canada
    Posts
    3,325
    Likes (Given)
    2375
    Likes (Received)
    2351

    Re: Cabin Heat, Water Cooled Engines - Which Way is Best and Why?

    Quote Originally Posted by Dan Thomas View Post
    My Ford Ranger and Hyundai Sonata both use the AC with defrost. My '89 Ford F150 did, too, as well as the three GM vehicles I owned ('91 Chev S-10, '81 Pontiac Parisienne and 2001 Cavalier). The only vehicle I have owned in the last 30 years that didn't was the 1951 International pickup I restored. It didn't even take in outside air for the heater. Just recycled the interior air so that one had to roll the window down for defrost. Lots of fun in an Alberta winter.
    Just verified again today on my 2 BMWs- They don't, at least this morning at -16C.

    Let's look at 2 scenarios-

    1. Evaporator upstream of heater core, OAT -20C. Turn on a/c. What happens? Nothing, since any moisture that condenses on the evap core will freeze instantly and you'll have frost and then ice buildup on the core which will eventually block all airflow.

    2. Evaporator is downstream of heater core, OAT -20C. Turn on the a/c. What happens? Heater warms the outside air to +50C before it enters the evap core which then cools the air. So how do you get warm air in the cabin?

    Having the a/c on when the OAT is below freezing (as in winter, post #84) CANNOT help to reduce humidity. When the OAT is above freezing, it certainly can, which is why some cars tie the a/c into the defroster- good on a rainy day, useless on a -20C day.

    I don't think Bill is planning a/c in his airplane. Or maybe he is...
    Last edited by rv6ejguy; February 22nd, 2019 at 08:58 PM.
    Ross Farnham
    Racetech Inc.
    16 years and 428.6 hours on Subaru Turbo powered RV6A
    "The world is changed by your example, not by your opinion" Paulo Coelho
    http://www.sdsefi.com/aircraft.html




  11. #99
    Registered User Toobuilder's Avatar
    Join Date
    Jan 2010
    Location
    Mojave, Ca
    Posts
    4,160
    Likes (Given)
    416
    Likes (Received)
    2894

    Re: Cabin Heat, Water Cooled Engines - Which Way is Best and Why?

    Thought this was a particularly timely post from VAF. Please see the note about "computer fans"

    http://www.vansairforce.com/communit...18&postcount=1

  12. #100
    Registered User Tiger Tim's Avatar
    Join Date
    Apr 2013
    Location
    Thunder Bay
    Posts
    2,589
    Likes (Given)
    1381
    Likes (Received)
    1451

    Re: Cabin Heat, Water Cooled Engines - Which Way is Best and Why?

    Quote Originally Posted by Toobuilder View Post
    Please see the note about "computer fans"
    I kind of like how his canopy defog and avionics cooling schemes are one and the same. I suppose if you installed enough old radios you wouldn't need any other cabin heater...

  13. #101
    Registered User Toobuilder's Avatar
    Join Date
    Jan 2010
    Location
    Mojave, Ca
    Posts
    4,160
    Likes (Given)
    416
    Likes (Received)
    2894

    Re: Cabin Heat, Water Cooled Engines - Which Way is Best and Why?

    Right! One can claim partial justification for a $50k panel... It eliminates the need for a heater!

  14. Likes gtae07, rv6ejguy liked this post
  15. #102
    Registered User
    Join Date
    Jan 2011
    Location
    US
    Posts
    3,093
    Likes (Given)
    1120
    Likes (Received)
    1328

    Re: Cabin Heat, Water Cooled Engines - Which Way is Best and Why?

    Quote Originally Posted by Toobuilder View Post
    Right! One can claim partial justification for a $50k panel... It eliminates the need for a heater!
    I think we need to think bigger. The use of normally wasted heat(Hello, DoE/NREL) to enhance aviation safety (Hello FAA/NTSB) is bound to be worth a grant of some type. Get an experienced grant writer who will work on contingency and it can't fail. Look for "first-of-its-kind continuous defog with no pilot action required and no additional energy use", unprecedented inter-system synergies," etc.

    I'd be surprised if this won't pay for the plane.

    PS. I doubt there's enough heat from the avionics to do much good, but that's hardly the point.

  16. #103
    Registered User wsimpso1's Avatar
    Join Date
    Oct 2003
    Location
    Saline Michigan
    Posts
    5,269
    Likes (Given)
    1932
    Likes (Received)
    2600

    Re: Cabin Heat, Water Cooled Engines - Which Way is Best and Why?

    Quote Originally Posted by rv6ejguy View Post
    Just verified again today on my 2 BMWs- They don't, at least this morning at -16C.

    Let's look at 2 scenarios-

    1. Evaporator upstream of heater core, OAT -20C. Turn on a/c. What happens? Nothing, since any moisture that condenses on the evap core will freeze instantly and you'll have frost and then ice buildup on the core which will eventually block all airflow.

    2. Evaporator is downstream of heater core, OAT -20C. Turn on the a/c. What happens? Heater warms the outside air to +50C before it enters the evap core which then cools the air. So how do you get warm air in the cabin?

    Having the a/c on when the OAT is below freezing (as in winter, post #84) CANNOT help to reduce humidity. When the OAT is above freezing, it certainly can, which is why some cars tie the a/c into the defroster- good on a rainy day, useless on a -20C day.

    I don't think Bill is planning a/c in his airplane. Or maybe he is...
    Well, like I said at the beginning, the AC compressor is disengaged whenever the evaporator coil approaches freezing to avoid coil icing. To clarify, it is set up to disengage the compressor when coil temps are below about 36 F. Whether any one manufacturer does or does not run the AC with the demist is not particularly important to the discussion of what is the best scheme for running cabin heat and windshield frost prevention in the vast majority of our little airplanes, as AC is rarely installed.

    I was not asking about AC here because I will probably not go there...

    So, where does one get a strong highly reliable heater core? Or should I just go for big muffs on the exhaust system and lots of flow through the system?

    Billski
    Last edited by wsimpso1; February 23rd, 2019 at 09:05 AM.
    Billski's opinions expressed here are available free and may be worth the money you paid for them. Understand that they are based upon a successful combination of education and a lifetime of experience using that education, but I can not know everything about your circumstances. Your choices are yours alone, and you must be the final judge on what you do. No whining...

  17. #104
    Registered User davidb's Avatar
    Join Date
    Jun 2008
    Location
    Vacaville, CA
    Posts
    1,557
    Likes (Given)
    383
    Likes (Received)
    390

    Re: Cabin Heat, Water Cooled Engines - Which Way is Best and Why?

    Quote Originally Posted by wsimpso1 View Post

    So, where does one get a strong highly reliable heater core? Or should I just go for big muffs on the exhaust system and lots of flow through the system?

    Billski
    http://www.seareycanada.com/CLA%20He...tstruction.pdf

    I have the smaller of the two on my plane. Probably wont fit your needs but they are light and simple. They work good IF the fluid is hot enough. My cooling system is simple in that there are no thermostats or separate loops and valves. If its cold out, the coolant runs cold. Id need to restrict airflow to the radiator in order to get meaningful heat in cold conditions.

  18. Likes wsimpso1 liked this post
  19. #105
    Registered User
    Join Date
    Dec 2004
    Location
    Hamilton New Zealand
    Posts
    374
    Likes (Given)
    142
    Likes (Received)
    148

    Re: Cabin Heat, Water Cooled Engines - Which Way is Best and Why?

    Noting that I can't remember Billski radiator config.

    Considering that of any flight point the minimum radiator drag is roughly at the same time that radiator temp is at its max allowable (assuming variable geometry in the radiators exit)

    So what is the expected temperature range expected of the air aft of the main radiator, instead of adding weight for an other cooler element is it possible one can get sufficient warm air from aft of the radiator to provide cabin heat, even if it requires a greater range of viability of in the radiator exit size & electrically control blanking panels on the radiator.

Similar Threads

  1. Cabin heat
    By dirtstrip in forum Firewall Forward / Props / Fuel system
    Replies: 29
    Last Post: January 16th, 2019, 03:00 PM
  2. Water cooled VW head
    By STDJantar2 in forum Half VW
    Replies: 3
    Last Post: September 15th, 2018, 08:46 PM
  3. Cooling Schemes for Water Cooled Engines
    By wsimpso1 in forum General Auto Conversion Discussion
    Replies: 90
    Last Post: September 4th, 2016, 04:04 PM
  4. New water cooled heads?
    By Cabover in forum Volkswagen
    Replies: 51
    Last Post: January 4th, 2015, 05:11 PM
  5. Oil Cooler Outflow to Heat Muff for Cabin Heat?
    By BedeFlyer01 in forum Firewall Forward / Props / Fuel system
    Replies: 2
    Last Post: June 24th, 2010, 11:52 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •