Cabin heating System

Here’s my exit duct post cure and cleaned up. The edges extend down so I can flox it to the heater case later.

In pic 3 you can see the really open exit area.

Post cure duct

The form is removed

You can see good flow

The top of the heat exchanger needs a place for the now hot air to exit. Time to make another duct.

I used the blue foam again as its pretty good to carve. Pic 2 is my sculpture in place. Pic 3 and it is now covered in two plies of BID after I again microed the foam in another cure cycle.

Planning

The form

Glassed in place

I used Garolite G10 for a base on my duct. There was a fair bit of under the seat fitting before I arrived at this shape. Meanwhile the RV box had been heavily modified and I think I can make this all work.

Pic 2 has the garolite G10 floxed in position and after cure a wide cut out. I also added some micro internally to transition the edges with the idea that this would help air flow.

Pic 3 is the modified box in place, which will get screwed into position. I need it removable for maintenance, or rather just in case it needs maintenance one day.

A flat garolite base

Exit cut out

Fitting the modified box

Next up for the heat system was to get the air from the duct to the on-off box. This is to be via a turn of about 45 degrees and still some expansion.

Pic 1 shows my 2nd attempt at a basic shape to work as a head. This was tricky for some reason. Eventually I had it as you see in pic 2.

I gave it a couple of coats of micro and sanded it back over a few days. Then I glassed it with about 3 plies of BID. It was a funny shape so there was a fair bit of overlay. It is nice and strong.

Pic 3 is after all this and the cure and a good clean out of the mold or ‘form’. A great result.

Foam blob

Carved to shape

Glassed and cleaned up

Again this was many hours, overseas orders and a lot of thinking.

Pic 1 shows the heat exchanger in its case, the Y valve and an RV alternate air box that I thought I could modify into an open or closed shut off valve. Pic 2 is another look at the box before I hacked it up and a simple push pull cable that would later operate it.

Pic 3 gives an idea of where things will go. That RV box needs to be right in the corner. I still want room for cables and wires on that side. I need an exit for that straps that will hold the ferry tank and inboard of the radiator there needs to be the rod from the on-off valve. Everything that has air also needs a straight path where possible. Tricky stuff.

Parts

More parts

Placement planning

That Y valve was really stiff. I pulled it apart and spent a few hours carefully sanding the main surfaces until it moved like it had very little friction. Now it was usable. I also ground it down to a minimum body thickness.

Next up was working out how to actuate it. I figured a push pull cable would work and using a mixing stick I found it could be quite short and still be fully operational.

While a lot of other work was happening I was constantly working on the fuel system layout. I needed to be able to use the main fuel shut off valve from the front seat and have the actuator arm still fit in with the heat exchanger in place. I wanted the valve connections to not be under stress as well. More thinking. I did source some connectors that suggested there was room to mount everything I wanted in line.

Rebuilt valve

Check ‘throw’

Continued planning

Another little job. You’ll see later why this goes here. Its my heat vent outlet for the pilot (me!). Yes its in a funny place. My plan is to direct the hot air around the canopy.

My thinking is that it is a very short run from the heat exchanger to this point. If I was to direct it all the way to the panel so the vent faced me I would loose a lot of the heat during the journey through various ducts. This vent is near the heat source so it should work well.

Of course I had to move that fitting you see in pic 1 as it was in the way of the vent. Pic 2 is during the cure a few inches inboard.

Pic 3 is the vent. Yeap I forgot about the canopy actuating rods. It might be .5″ too near the edge so I may (or may not) have to move it later. Such is this journey…

You can see in the first two pics that mounting the plywood pump base was a bit of a challenge. Hot glue and sticks really work well for this sort of thing. I use shrink wrap on bolts to protect the threads when doing nearby glass work.

I teased out holes where the bolts were in the BID without breaking any strands of glass and got it all sitting well. Pic 3 is after the clean up and I’m happy with the result. The pump ‘just’ fits in there. I’ll run one line through the firewall to the inlet with RTV and a fireproof hose. The other pipe will go to a usual firewall/bulkhead fitting.

Glue and sticks work

A solid mount

Cleaned up well

Time to mount my heater oil pump. It took a while to work out a good place and a method.

Pic 1 has a piece of firewall plywood of which I have a full sheet. I’ve floxed in bolts matched to the pump in position of course and then added BID to secure the heads. Pic 3 is prep for what you will see in the next log.

Plywood base

Base floxed and glassed

Prep for the moment

Pic 1 and the forward feet duct system is done. That was a biggie. Pic 2 and you can see I have the right duct in place and presenting to it’s little trap door.

Pic 3 and I have glassed the bottom of the heat exchanger so its no encapsulated.

Ducts all secured and hidden away

Right forward duct in place

Heater bottom now glassed

Meanwhile I needed to put my heat exchanger in a fiberglass case. The plan is just to cover it completely then slit it open to get the exchanger out. It needs a few things in there before it is closed up for good.

I used some foam and sticks as you see in pic 1. Pic 2 has gaffer tape covering. I should have used balsa wood or something dead flat. Just to make a neater job. Functionally no difference at all. I just like to do the best I can and gaffer was not the perfect answer for this job. It did work however.

Pic 3 and I have glassed the top and sides. I’ll do the bottom after the cure.

Case filler

Gaffer tape for a release

Top and sides glassed

Before the shroud went on I had to work out a way to get the hot air to both feet. I put a separator onto the top of the wheel box front section as you see in pic 1. Next up were some vents in the shroud or openings if you like.

Pic 2 was the quite large job of securing the shroud. I’ll save you all the pics. In short, I floxed it into position with the clicos still in place. After cure I removed them and then added some BID tapes to tidy up. There is a finished pic in a couple of logs.

Pic 3 is my hi tech sliding trap door control. Just a bit of AN hardware and a slot. Works a treat.

Note the feet vent separator

Clicos work

Trap door slide control