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N282RV

Well Known Member
Anyone thought about or done a oil cooler heater in the cabin? something like putting some bulkhead fittings on the fire wall and use a fan to blow through the cooler to extract the heat. I wonder what the change in temp would be, I would think you could run two coolers, one for engine cooling fwd of the firewall and have a adjustable valve to close it during cold weather and the one in the cabin would be used for the heat extraction. I supppose getting the oil hot enough to make this work may be a problem in the winter.
anyone with any input, data, ect. ?
I thought about this a few months ago and I see someone asked the same question in another thread so here it is.
 
It's been tried before on other types of airplanes without success. There is just not enough heat in there to transfer. Look at it this way. Your exhaust gas temp is in the 1200-1400 range and even at that, a standard heat muff loses most of its ability to transfer heat when the OAT is below 10 dF. Your oil is only 200-400 dF. Just not much BTUs there.
 
Mooney

I was wandering around a shop the other day and saw a Mooney plumbed to take oil cooler heat into the cabin.

Some quick math. If oil runs 0.8 Btu/lb and 5.5 lbs/gal and if we circulate 10 gpm oil through the cooler with a 10 degree loss through the cooler per cycle, then the heat transfer from the cooler is 33,000 Btu/hr. A fair bit of heat. You can heat a small home on 33,000 Btu/hr.

Heater cores in autos run about 200 degrees as well.

I do wonder though, how much oil the vernatherm is allowing to circulate at 10 degrees in cruise. My oil temp rises fairly quicly to 180 degrees in the winter, then holds, presumably when the valve opens to the cooler. This would also suggest that there is a fair amount waste heat available.

As you can tell, I'm tempted to try it!
 
My experience comes from the EZ crowd, who have tried the darnedest things to get heat up to the pilot's feet. They've tried oil coolers, electric heaters, small fires, etc to get things warmed. None worked very well.

I don't really care for the added complexity in the oil system (read that vital engine system) so that if there's a problem, I'm in real trouble. There are suitable solutions to heat the cabin that don't involve the oil system which I would consider more safe.

But hey, that's why it is called experimental aviation. Go for it and let us all know how it turns out!
 
Not in cabin

I am going to try the same set-up. Of course, it helps to have an angle valve with Ney nozzles, which really boost oil temps.

Anyway, I would not even think about putting a cooler in the cabin. Way too much trouble and danger. I am going to mount the cooler on the firewall, with a dedicated plenum and exit, in the most std manner. However I will change in that the exit air will be "valved" to go either outboard (summer) or into the cabin (winter), similar to heat muff plumbing. No major changes or alterations needed. KISS. I plan on using insulated ducting to keep as much heat in the duct as possible and a Stewart Warner cooler to get the most effecient heat extraction.
 
Oil Heater

That is what I had in mind. Everything is ideally located now so I should get off my duff and try it. Just need the hole in the firewall. If it does not work, rivet some SS back over the hole. I will let you know how it goes.
 
Whatever path you take, remember that you're cutting holes in the firewall. Take a look at the firewall article in this month's Sport Aviation... pictures worth a thousand words. Take care that you don't build a blowtorch tunnel.
 
Stainless always

DanH said:
Whatever path you take, remember that you're cutting holes in the firewall. Take a look at the firewall article in this month's Sport Aviation... pictures worth a thousand words. Take care that you don't build a blowtorch tunnel.
Click to expand...


Yes, you should always use stainless penetrations. I was going to incorporate their heat box in mine. That way it is safe and easily switched over to muff heat, if that is deamed to be needed.
 
N282RV said:
Anyone thought about or done a oil cooler heater in the cabin? something like putting some bulkhead fittings on the fire wall and use a fan to blow through the cooler to extract the heat. I wonder what the change in temp would be, I would think you could run two coolers, one for engine cooling fwd of the firewall and have a adjustable valve to close it during cold weather and the one in the cabin would be used for the heat extraction. I supppose getting the oil hot enough to make this work may be a problem in the winter.
anyone with any input, data, ect. ?
I thought about this a few months ago and I see someone asked the same question in another thread so here it is.
Click to expand...

This has been done with varying success by the canard guys, who have more trouble making exhaust muffs work. An example of a successful installation is here.

The successful installations seem to have a couple of things in common: 1) a second oil cooler inside the cabin and 2) a fan to recirculate cabin air through the cooler.

They vary in how they are plumbed, and in how oil is controlled through the "heater core."

It seems that people using outside ram air through the cooler rather than a fan have limited success.

I appreciate the objection to monkeying around with the oil system, but I think that a failure of a carefully constructed system is probably less likely than the risk of a failure of the "primary attitude control system" secondary to carbon monoxide from a fault in the more typical heat muff system. Both would be bad, but on balance I'd prefer engine damage/failure from oil starvation to pilot failure/damage from CO.

I have a small oil cooler on the bench for just this reason, but haven't gotten around to engineering a system yet.

James Freeman
 
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Any firewall penetrations for SCAT hose with an aluminum heater valve are subject to quick melt through in the event of an engine fire. Most RVs use this setup.
 
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