Cockpit heating Ideas

[skippydiesel]

I froze a few times, winter just gone. The unpleasant experience (mainly lower legs & feet) has got me thinking about possible comfort strategies.

 

I did purchase, a bit late in the season, some of those chemical toe/foot warmers  - so have yet to try them.

 

The luxury alternative is  a cockpit heater.

 

Seems to me there are three options for heating the cockpit;

 

• Traditional; well proven heat from exhaust system. This should be a light weight, almost instantaneous (on start up) heat source. Unfortunatly comes with significant complexity (ducting) hole(s) in the firewall, increased noise when hot air vent open and the ever present possibility of CO poisoning.
• Coolant (Rotax); Seems quite a few Rotax powered light aircraft have automotive style cockpit heat courtesy of a small heat exchanger & fan forced air circulation.  Much reduced chance of CO poisoning, no increased noise, smaller firewall penetrations. Down sides are, slower  to deliver the warmth  & additional weight. Users claim little to no impact on engine coolant temperatures.
• Oil; Dont know of any aircraft using an oil cooler/heat exchanger in the cockpit. May deliver similar benefits as coolant system. Down sides similar to coolant,   probably increased chance of oil system failure. While a Rotax can continue to a safe landing with diminished/nil coolant, it wont get far with no oil.

 

I welcome criticism of the above points and any additional thoughts you may have on the pros/cons of cabin heat.

 

Despite my desire to follow the KISS principals in all things aviation sometimes one must be pragmatic - I have started to plan for the possible future installation of a coolant heating system.

 

I hope to hear from Forum members on;

 

• What they have in their aircraft, the advantages/disadvantages.????
• If fitted a coolant heating system - does it work, how well,  what would they do differently, where did the source the components, etc etc?????

 

I look forward to some great suggestions & 😈

 

 

 

[Moneybox]

I hadn't thought of a coolant type heater. That's the option I'd choose. I should have had some new ones somewhere, fan and heater radiator combination. I just asked Mrs M but she hasn't seen them. I'm away flying this weekend but if I remember I'll have a look next week. I probably bought them through Ashdown Enterprises, that's a guess because it was ten years ago.

[Moneybox]

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[Moneybox]

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[Thruster88]

It is possible to go snow skiing all day in sub zero temps and 15 knots of wind chill with appropriate clothing. These electric pants could also be an option. 

 

The excellent heater in my RV6 has the very small heat muff on just one of the exhaust tubes, not much risk of CO poisoning compared to traditional systems that enclose the entire muffler. 

 

 https://www.ebay.com.au/itm/304932708513?_skw=Electric+heated+pants&itmmeta=01K9Z4N7758VP6HNDXYJCJPJ2M&hash=item46ff67e0a1:g:zI8AAOSwQzRkWM-r&itmprp=enc%3AAQAKAAAA8FkggFvd1GGDu0w3yXCmi1dCfX5Fg9ds%2FJgf5ULe0IroBHF7iOfloqn%2BguZ2%2BFh7h27Z85zqM0VZ6eizoV%2BQdbOzrT7bXqXxu%2F32JMo53oBAo08O%2F9av5xkUCqnWJzkyjhMvEmnWw%2BFWDpD5ihBIukeGwAqzhQf3NAIGM4AmM2Gy0m%2B1V4%2BB6Mc469jgWjTFYsa6ZES2uWCm%2B8e3VyM%2Bd16uBmMoEEhtu2UaIdKlcz9iUpZUcv0add6vJD2JCsfoYPbyFSMJHkjir%2Feyj4UHumH6Mf5zTDYsS2SyuH00Xcf6jZnqhC0NFz%2FsrXZOHaxhRQ%3D%3D|tkp%3ABk9SR-bz1OTPZg

[facthunter]

The coolant use would be when the Motor is Probably already tending to be Overcooled in cold ambients.  Consider a small electric unit driven from the Planes electrical system?  Nev

[T510]

When I was working in Alaska a lot of the cars were fitted with these 12v heaters.

 

https://www.amazon.com.au/OAOJUBR-windshield-cigarette-defroster-detachable/dp/B0DSCGQ9SZ/ref=sr_1_6?dib=eyJ2IjoiMSJ9.UXyOOFX11FGTHrWOCTIL5VbzPDy7bytBdPn7ta7fOUBJQ99eyYbgG49yuAOogJNDiGVDmnv98BRC93nj6mSW0DPkvHcFtoJcvA_1BUgD972aixlKNDTvvwm_hH45j_pTBwX7uIolH3V4A1rxX9cUd2QzjJpveKlUpEXpm6Nf-JeHZNEJ0lzpHEIfWytZDM9V0qmjApdyG75dih2Zuhj4JV3lF2HRhn91Nj53x2HOAQYT5_BMlsnmJUrjT39NNxJ_Wf_e2-AJZxfKPN3InjfMXlEza08hNq7W6NELsS03OOA.7motdO6DA7hlCB1-Hts_Ha1bn_mcAk9_xpITMjobx84&dib_tag=se&keywords=12v+heater&qid=1763087361&sr=8-6

 

 

[Moneybox]

1 hour ago, facthunter said:

The coolant use would be when the Motor is Probably already tending to be Overcooled in cold ambients.  Consider a small electric unit driven from the Planes electrical system?  Nev

How many amps do you get from a Rotax charging system?

I doubt there’s enough spare to run a heating element.  

[FlyBoy1960]

At 12 V running 120W it's going to draw 10 A at full power. I'm guessing it won't cycle on and off too often with a thermostat so you can expect it to use 10 A all of the time. 

 

The best way is to run a 2nd radiator on the coolant circuit but have the radiator inside the cabin with a bypass so you can open the water flow to go through the radiator inside the cabin with a blower to push out the hot air. Just like old-fashioned cars used to do it.  Then if it is summer just close the valve and the radiator in the cabin will just have ambient temperature water in it, open the valve and the hot water will start to flow again.

[FlyBoy1960]

don't think the diagram is perfect because the direction between the engine and the maiden radiator is wrong (I think) but it will help you understand.

 

[kgwilson]

An electric resistive heater is very power hungry although 100% efficient. A standard 1 bar household heater consumes 1 kilowatt of electricity at 230 volts or just over 4.4 amps. At 12 volts that would be over 80 amps. You would need 20 amps minimum and that wouldn't be that effective with OAT below zero. A simple exhaust shroud is the most effective IMO. The Jabiru one fits around the straight exhaust pipe and not the muffler which is similar to T88s RV on one exhaust pipe and much reduced risk of CO poisoning.

[facthunter]

A pipe shroud will make the Pipe Hotter than normal when no air is flowing through the shroud. You have to use it or vent it. You don't need anything like 1000 watts in a small area if it is sealed reasonably. Taking more heat out of the coolant is likely to cause it to run well below Ideal in freezing conditions. It's only cooling the Heads, not the entire Motor. Nev

[Reynard]

I have a stainless steel exhaust muffler with a shroud. The cabin heater ducted from this shroud is very very effective. I have an electronic CO detector. Happy days.

[RFguy]

yep.

the cabin muffer shroud heater or water jacket heater produces literally kilowatts of heat for the cabin.....

 

and it is there for free

if you want to burn up 300W say in a resistive element, your alternator might take 500W of engine power to do it (2/3 of a horsepower) , and create an extras 1kW of heat  doing that....

 

so, that's why every system uses waste heat . even the electric aircraft use Waste heat from the water cooled engine and water cooled motor driver.

[BurnieM]

Isn't clothing a simplier option ?

Maybe a pair of sale ski pants and jacket.

 

[facthunter]

Have you flown  Rotax 912's in cold conditions?  To get the temps right you have to do something like block 1/2 the Intake with foam rubber. I've also used electric Carb heat successfully. Your second sentence makes no sense, Glen. That would be a very inefficient Alternator, with those figures.. The Dreamliner is airframe deiced entirely with electricity. Yes the other stuff is free, but not  entirely without consequences. Perhaps a small Heat pump could cool the Plane as well on hot days? Nev

[skippydiesel]

4 hours ago, FlyBoy1960 said:

 

The best way is to run a 2nd radiator on the coolant circuit but have the radiator inside the cabin with a bypass so you can open the water flow to go through the radiator inside the cabin with a blower to push out the hot air. Just like old-fashioned cars used to do it.  Then if it is summer just close the valve and the radiator in the cabin will just have ambient temperature water in it, open the valve and the hot water will start to flow again.

The only car I know/have expertise of, that uses exhaust heat is the old VW Beetle -they could kill you.

 

To the best of my knowledge, all post WW@2 liquid cooled enclosed vehicles  (car & trucks) - use a small  heat exchanger/radiator + fan & ducting  to circulate the hot air. They all had a regulating  temperature/flow valve OFF - Full On. Most, if not all, also had air direction  & fresh/cabin circulation controls.

 

Modern cars use the same system, fancied up with such necessary & unasked for gizmos like "climate control"😈

[skippydiesel]

1 hour ago, BurnieM said:

Isn't clothing a simplier option ?

Maybe a pair of sale ski pants and jacket.

 

The thermal pants may be the way to go - my upper body never seemed to get cold.

 

Potential down side is - getting hot & sweaty when I get out of the aircraft. I suppose I could just strip off the leggings - may cause a deal of  amusement 😈

Edited November 14 by skippydiesel

[BrendAn]

1 hour ago, facthunter said:

Have you flown  Rotax 912's in cold conditions?  To get the temps right you have to do something like block 1/2 the Intake with foam rubber. I've also used electric Carb heat successfully. Your second sentence makes no sense, Glen. That would be a very inefficient Alternator, with those figures.. The Dreamliner is airframe deiced entirely with electricity. Yes the other stuff is free, but not  entirely without consequences. Perhaps a small Heat pump could cool the Plane as well on hot days? Nev

Dreamliner also has powerful generators

[kgwilson]

Many EVs use heat pumps. Mine does. Some call them reverse cycle air conditioners. They are greater than 100% efficient. An internal combustion engine is about 30% efficient. Most of the energy from the fuel is converted to heat. Use that heat as best you can & an exhaust shroud is by far the most simple and effective way to do it.

[BrendAn]

2 hours ago, skippydiesel said:

The thermal pants may be the way to go - my upper body never seemed to get cold.

 

Potential down side is - getting hot & sweaty when I get out of the aircraft. I suppose I could just strip off the leggings - may cause a deal of  amusement 😈

why not a flight suit.  you can look like maverick when you exit the sonex

[onetrack]

The last thing I'd want in a cramped cockpit is a radiator carrying coolant to and from the engine. Too much potential for leakage, burst hoses, split seams, etc. The exhaust system cuff gets my vote.

[Reynard]

I should have added that on long flyaways I can easily dry my socks and jocks in the cabin with the exhaust shroud heater.
Yeah, I fly by myself a lot…….

[facthunter]

You lose a lot of heat when it's ducted.  Water in pipes and heat exchanger weighs a bit..   The heat Pump gives you heating and cooling  at good efficiency. Nev

[corvairkr]

When I had my Rotax powered 601 HDS I made up a fibreglass scoop similar to this gyro setup. It captured a portion of the hot exit air from the radiator which was then plumbed to a cabin heat airbox. It was simple and extremely effective.

 

jason