Cabin heating System

The trap door received even more mods to get it sealing better. Corners were removed and bits of glass added. It’s getting pretty good and still fits.

Meanwhile I started making strange ramps to it as you see in pic 2. Can you guess whats going on?

Pic 3 shows that I’ve had to put nutplates secured around the Andair valve hole. Why nutplates instead of just lock nuts? Well its the same reason as the Pic 2 transitions. Hmmmm

In place with the new mods

Difficult transitions

Nutplates to hold the Andair cover on the pilot side

Lots of fun making the aluminium plate. I think its 6061-T6 and a fair thickness. I made a lightning hole too that allows access to all the fasteners.

The valve nut plates were match drilled and it all worked out pretty well. I have more photos later of the ‘system’ in place.

Front spacer view

Rear view all secure

Front view

My big idea for this Andair valve was to secure it to the fuel pumps rather than the floor. I’ve been worried about the precision needed to have the valve fit without stressing the joins.

This way the valve and the pumps are one joined unit, then the pumps are secured to the floor. Got it? So I need a plate of aluminium between the two with oval holes and floating nut plates.

I soon found that the valve and the pump were nearly 0.25″ off the same plane. My solution was to use a garolite spacer. The Andair already had spots for nut plates which was helpful too. I had some fun making it all nice as you see in pic 3.

Cardboard cutout first

Garolite spacer

Nutplates on the valve

Now that the heater was in place I could think about a cover. It needs one to protect against the main valve being interfered with. More to the point I’m going to have the ferry tank bladder back there and it will really press on the sides of things so I’m very mindful of that.

Pic 2 shows a foam problem I have. All the stuff I have left is thicker than needed so I have to route it thinner using my thinning box.

Pic 3 and I’ve glassed one side of the cover. Progress.

Trial fit

Foam too thick? Fix it

Glassing the cover

See, pic one shows I have cut off the old outlet and floxed on this new shape? That was lots of fun.

Pic 2 is how it works. I’m again using the tight fitting PVC tubes as connecting holders that allow easy removal. I was lucky to stumble onto this idea. You se it all starting to take shape.

Pic 3 is a problem I fixed. If you look carefully you can see an indent under the purple connecting rod. It was just too close to the heat exchanger so with a couple of hours work I made a concave insert to take care of the problem.

New outlet

Eyeball in place

A problem fixed

Here we have the Click bond and nut plate in position on the side wall (Pic1) Quite a bit has gone on here with position, the usual prep and BID layers. I tried a few types of click bonds too. The lower ones are receptacles to hold the screws that go through the heat exchanger. I tried smaller sizes and so on. What I have worked.

Once they were up I then found I could drill right through the Y valve at a certain place and have a floating nut plate, riveted to a hard point embedded in the wall. It is now all secure and like a rock.

Pic 3 I’ve shown before. I’m just checking to see if you have gone to sleep yet.

Click bonds all positioned

Secured

I have to change that outlet

Here we go. Pic one of my duct outlet ready for the back seat which you can see in pic 2. So the idea is that the air goes out of the heat exchanger up to the eyeball vent.

That can be open or closed. Especially if closed the air moves along the back of the seat cavity and then down the seat to underneath into the front duct system. Simple eh?

Pic 3 is while I’m gluing on some click bonds and later a floating nut plate to hold the heating system to the wall. I think I’ll have some pics in the next log or so.

Top of the duct

Epoxying the duct in place

Sticks make great positioners

Here are the front ducts all in place and going to the doors. It looks like it might work.

Pic 2 is the rear duct getting a ramp, you’ll see why soon.

Pic 3 is another idea I’ve worked out for the PAX or Guy/Gal in the back (GIB) outlet Its better than the previous one already floxed in place. Here you can see the blue foam former ready for some glass.

Front ducts

Rear duct modification

Air corner turning device

Time to weigh my assembly and about 3lbs 5 ozs with some parts to be removed and added still. I hate the extra weight but thats better than being really really cold as I have been when flying. I sure hope this system works the first time.

Pic 2 is some of the ducting I’ve been making. Its very light and I use rectangular aluminium beams as the form with some duct tape for release.

Pic 3 has the expanding duct from the NACA finally microed in place and the duct from under the seat running along the side to the front feet exit sliding doors. You remember the ones that go to my feet around the front wheel well.

This was a real fiddle to finally get it sitting correctly. I dug out more floor so the duct outlet remained round at the exit and lots of jiggling and cutting while hanging upside down. It was a couple of days in the end that felt like a week for this simple step.

Weigh in at 3lbs and a bit

Duct off the form

Ducts under the front seat

The air flow heat direction valve gets operated by a push pull cable. I needed some click bonds placed to hold Adel clamps for this.

Pic 1 is my usual procedure. I drill four 1/32″ holes or more in the click bond base and then sand it and clean. I also prep the fiberglass surface with sanding and a light swish or acetone on a just damp rag to clean the surface of this and the metal mount.

Next up plenty of flox with the threads protected. I do a quick cure in front of the heater and an hour or more later clean it all up. Next are two plies of BID over the top laid up on foil and peel ply over that. Pic 2 is what we now have.

Pic 3 and I’m loosely trying out the clamp positions. You’ll notice I have a metal actuator for the valve now as well. These small steps are pretty easy and fun, I just stick some music on and it gobbles up the day. Many other jobs require huge decision making and a lot of pain while dancing from one foot to the other working things out!

West system flox

Two ply BID

Adel clamps placed

A few shots here of fitting the rear valve connection. While I went to some trouble to do this…in a few logs you’ll see I had a better idea and cut it all off.

A lot of this stuff went on with my one off design as it matured and became clearer. There was an overall plan but no detailed vision, just a beginning and an end. This process is the creative bit in between, or if you prefer where things are done more than once.

Positioning the new pipe

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Carefully floxed in place

A trial fitting

Here are a few jobs that happen along the way.

As I mucked up the first go at positioning the Andair valve in its correct rotation here’s the second attempt after filling and re-cutting the inlay hole.

Pic 2 is after some fun getting a working cable mounting system for the trap door on/off. You might notice I’ve also done more work on the box getting the edges to seal better. I spent hours fiddling with that thing.

Pic 3 is a shot of my pipe making process. I put plastic pipe on my rotisserie, glass it with prepreg or foil based layups and peel ply the outside which for once is easy.

Re-positioned valve

Cable clamping

Pipe making