Hi Guys,
Here is one option. Of course, feel free to add your solution to the list.
Since the pics from the old forum did not survive the port to SonexPilots, I thought I would recover what I could of my cabin heat solution. Properly implemented it provides good oil cooling and cabin heat without having to run scat tubing all over the place.
This is for a Onex with a Hummel 2400. Here is a copy from a recent email.
Here is a pic of while I was mocking up the firewall on lexan. It didn’t end up exactly like this, but you can see the oil cooler/cabin heat assembly.
The assembly is fed fresh air with a NACA vent on the right side. I don’t like to drop hoses when I remove the cowling, so I hinged the NACA to the firewall and pull it to the cowl with four quarter turn fasteners.
I later found out that the right side of the cowl is about the worst place for the NACA as far as pressure rise. So, I had to add a little scoop to get adequate air flow.
I tested the cabin heat one day when the temperature was right at freezing on the ground. So about 25 Deg at altitude. The temp of the air coming into the cockpit as measured by a probe dangling down from the instrument panel was about 84 Deg. Had to turn the heat down after warming up from a cold preflight. This picture was taken at morning civil twilight. Oil Temp was 185 Deg F when the picture was taken.
BTW, here is a link to the Oil Cooler I used: Oil Cooler, 7 Plate, from Aero Classics, aec-8000075.
Not all that expensive once you subtract the price of heat muffs and a standard oil cooler.
Wes
1 Like
Such a good solution Wes!
I also used my oil cooler as a heat source. I have a plenum behind my top mount cooler, and two 1.75” hoses that leave it. One I run down to a heat valve.
I made the flapper out of stainless. Also the hinge is stainless and the clevis. It is pull to turn off, which is the most important part in case of a firewall forward fire.
That flapper gets covered with an aluminum valve body. You can buy stuff like this from AC Spruce but I made my own.
Those two scat tubes eventually plug into a couple of reverse scoops on the bottom, that I added when trying to improve oil temps back in 2023. When it gets really cold I block off the exit that does not have a heat valve. I differ from Wes in that I don’t mind plugging in hoses when I R&R the cowl. I’ve got a sequence that works. Wes’s design is really cool though.
Inside I made a little deflector to shoot the heat down in the foot area. That is the control cable going through it.
A key part of having this work, and flying in the Northern Illinois/Wisconsin arctic climate is keeping the oil temperature up. So I have blockoffs for the exit and the cowl inlets.
With our heat system there is very little danger of heat stroke. But it makes the cabin a lot more livable. I really need to work on turning off the air conditioning in the winter - there is always a draft coming up from below. I am thinking of making boots for the aileron pushrods and flap torque tube.
I think the coldest I’ve flown this in so far has been a couple degrees F above zero on the ground, and at 4500’ probably like -15F. I didn’t have OAT back then. But the air coming out of the vent was about 49F and the cabin was 39F.
Since I have hot rodded the AeroVee on my last go-around, the oil has been a lot hotter. This should be a benefit as the temperatures plummet. I had most of the cooling air block offs installed a few weeks ago and the oil temperature went really high on one of Adam’s early morning flights. Since then we have been keeping a spreadsheet of OAT, climb altitude, and oil temperatures so we can retrain ourselves when to add which blockoff.
2 Likes
I rob heat from one of the exhaust pipes on my revmaster 2300. It works well for keeping my feet warm and the sun does the rest.
1 Like
How did you guys that built custom ducting shrouds/boxes adapt the scat tubing to the flat faces? I’ve seen these used that look like they’d work great but was wondering if there’s a good lower cost way to do it: Aluminum Flanges For Ducting | Aircraft Spruce ®
1 Like
I took a rectangle of aluminum and laid out 2 rivet lines, one down each side. The distance between the lines ends up as the circumference. Drilled to #40, then curled the rectangle around a broomstick clamped in the vise, clecoed, updrilled to #30, and riveted. I use angle tabs to rivet the tube to the box and seal as needed with RTV.
