Cabin Heat & Window defrost

[Guest Ken E]

Thinking of choosing a Cozy. I need cold weather capability in the aircraft I choose (Canada). It appears the source for cabin heat in the Cozy is the oil cooler. How effective is this at -15 F and is there a viable exhaust manifold option given the rear engine configuration?

[John Slade]

Ken,

You may be thinking of Aerocanard, which uses an oil cooler up front. The Cozy IV plans use an exhaust muff for heating.

You'd have to talk to a Cozy driver to find out how effective it is.

I'll be using water cooled rotary engine in my Cozy, so an automotive heater core will work well for me.

Regards,

John Slade

http://kgarden.com/cozy

[Jim Sower]

Ken,

It might get more complicated than you would think at first blush. I have a Velocity which has two tandem oil coolers, one on the firewall and one in the nose. The nose unit has an inlet and exhaust, and part of the exhaust plenum is the nose gear mount bulkhead. A duct through that bulkhead "T"s into 1.5" scat tubing that enters the cabin through the bulkhead that the brake pedals mount on. In the summer, I close off the hot air as it enters the cabin and everything's OK. On a hot day, I don't ever get over 180 F on the oil temp. In the winter, with both oil coolers going, oil temps are lower and there's not much hot air coming into the cabin - there's no pressure to push the air into the ducting to the cabin.

 

What I think I'll have to do is make a flapper plate that when "closed" lays up against the bulkhead and covers the ducting into the cabin, and when "open" lays against the belly and closes off the main plenum outlet and forces all air coming out of the cooler into the cabin. The duct to the cabin, having much less capacity will slow flow through the forward cooler, reducing its efficiency while increasing the air temp coming out of the cooler. I may need a similar valve to inhibit flow through the rear cooler to raise the oil temp to 200 deg or more in normal ops.

 

[My] Velocity is seriously overcooled, with big, draggy inlets/exits. I will try and deal with all these issues one day (after I downdraft the engine)...

 

Try and examine ALL of the consequences of your various proposals...

Jim S.

[Guest Ken E]

First I would like to thank both John and Jim for taking the time to respond to this issue. John I looked at your website and congratulate you on your project.

 

So there, in fact, is an exhaust muff designed into the Cozy. And, in the case of the Velocity, cabin heat using an oil cooler as a source has some issues. Those are both valuable pieces of information. Is there anyone who has a Cozy, in a colder climate, and can comment on their cabin heat and defrost experience?

 

Thank you for helping me with this issue.

 

Ken E.

[unick3]

Jack Wilhemson and I solved the problem of low oil temps when using two oil coolers in series. We ran the oil line from the engine to the cabin heat exchanger (a oil cooler) then into a external oil control valve (mounted on the firewall). The control valve is set at 185 deg f. It works like an external vernitherm. It the temp of the oil from the cabin heater is <185 the oil goes directly back to the engine. If the oil temp is >185 it directs the oil to the external oil cooler then the engine. This way the engine ALWAYS sees about 185 deg oil whither or not you are taking heat out of the system with the cabin heater and/or the external cooler. I found the control valve in the Summit catalog (any race car catalog has external oil control valves which are set at different temps) Cost of the valve is ~$35.

 

We totally removed the heat muff. The oil cooler system will BLAST you out of the cabin with enought heat to warm your bones at any OAT.

[Guest Ken E]

Nick:

 

I appreciate your valuable reply as it provides an alternative solution to the cabin heat issue. It brings me one step closer to ordering cozy plans. Will keep you in mind for nose gear.

 

Thanks again,

 

Ken E.

[unick3]

Steve asked me about the remote thermostat. It is a perma-cool #1060. It can be ordered from JEGS at 1-800-345-4545 part number 771-1060 for $38.99. It directs oil to the exterior cooler when the oil reaches 185 deg f.

 

You can keep your engine vernitherm in place. All you have to do is install another oil cooler (small) in your cabin with a small bilge fan ($50 West Marine) to blow air through the core. Use your existing oil cooler in your engine compartment. The West fan generates NO radio noise at all.

 

You basiclly hook it up as shown in the diagram....

 

Your cabin heater is hot all the time. When you dont want the heat (summer) you just turn the fan off and the outside cooler automaticlly takes over the cooling of the engine..... Simple, automatic and it works.