Ch 22 Electrical System

Date:  04-30-2020

Number of Hours:  12

Manual Reference:  22

The Garmin engine sensor unit, GEA 24 is best close to the engine so that the sensor wire runs are short. The obvious place was the hell hole. The problem as usual, it wasn’t going to be a simple fit.  This happened over a month of fiddling.

This looked like the best spot but there was no where to fix the unit.

I added some foam to make a shelf. Then I trimmed it… too much and later added more foam.

After I had a shelf shape I added two plies of BID. This was in two stages as I needed a flox corner at the edge for strength. It was a ‘process’.

I then added 3 click bonds to mount the unit in place. After cure I realised that I couldn’t get the thing out in that configuration. Doh! So I had to remove the floxed in place click bonds and had to think again. A couple of hours of ‘fun’ there I’ll never get back.

The rethink put the clickbonds on the front edge and only two of them. I also made up a bracket from angle aluminium to hold the unit in position. Much better!

As a little extra, I floxed on another piece of angle on the bottom so the unit is held securely and can’t move even though it only has the two fasteners. Yes I did put two plies of BID over the click bonds and had to add a little micro to transition the edges. You don’t need photos… I’m doing this sort of thing all the time.

 

Date:  04-20-2020

Number of Hours:  25

Manual Reference:  22

This has been a ridiculous amount of work and I’ve done parts of it more than once. Some more than twice. The margins between each electronic box to allow other things to fit is within a millimeter or two A tenth of an inch as I usually measure things is far too big.

This item is the Garmin GTR 20, a VHF radio box that plugs into the G3X. It can go anywhere really, except everywhere else is full in my little plane. Its all ready to be mounted again on the middle tray. I thought I had it previously, but I was wrong.

This being the second attempt I had to remove clickbonds and glass from the top of the center tray to have another go at it.

Those brackets at the back will go in as a new central locking device for the whole panel. Greg, the nearby sheet metal guy, took pity on me and made up a tray and brackets. This has introduced me to a whole new way of thinking. I can use lighter metal and put in bends to make them stronger. Lets ignore the fact that people have been doing this in wing ribs for 100 years. I am relatively new to the game.

A big issue is clearance at the rear of the radio box so an antenna and Sub D can fit and I need to clear the bottom of the canard and internal rib. I did fail on this a couple of times but got it right in the end. How long do you want to read this thing? Be thankful I’ve left out some of the pain.

New clickbonds at the front.

The obligatory glass and clean up.

Now you might be getting an idea of the radio mount. You can see I’m making crazy extra fittings so it all locks together.

More crazy mount madness. Hours and hours of ‘fun’.

That bent edge upright is to help hold a tray that is coming. Yes more junk is going on top of all this. The side tray is my first go at bending up a bracket. I like it.

This is the beginnings of the fit.

It all came out, was modified and went back in again several times to achieve the above, Now I have good clearances.

OK. Its in. The middle clickbond is no longer needed as I’ve changed that idea. It stays for a while just in case its useful later.

Late tonight I floxed the brackets in place. I still have to rivet them to the tray sides and glass the clickbonds after cure but you get the idea.

 

 

Date:  04-13-2020

Number of Hours:  20

Manual Reference:  22

Working out where to put things has been some hours staring and trying various possibilities. Probably several days work that I don’t put in my logged times. As I work out where something might go consideration for the connectors, putting the canard on and what else my proposed position will interfere with comes into play.

The GSU25 is the Garmin AHARS or air data sensor unit. There is a provided connecting place on the back of the large main display screen with holes pre drilled and good to just bolt on. However…. in the Garmin install manual it says don’t put it there because the panel might vibrate a little and the AHARS needs to be a solid mount to the airframe. I eventually decided on the spot above as marked out.

Here you can see the clickbonds getting floxed in place for the AHAR unit. Below that is the GAD 27 a flaps/lights/trim controller. While this spot looks random it fits nicely below the main panel. It has a connector pocking out at right angles so I needed this in line with the lower panel items and as close as possible so I can’t kick it getting in the plane.

I like using whatever is handy to hold things in place with the epoxy sets, plastic conduit, weights, gaffer tape cheapo clamps, whatever works.

After the clickbonds are epoxied on I do a one or two ply BID layup to really ensure they are not going anywhere. Yes thats peel ply so I get clean edge transitions.

This is another fix for the Bus Manager box install. I made the fasteners too far from the corner initially to avoid the canard attachment bolt. That was a fail, so a new bracket was made and I’ve built up the attachment point click bond with some height. The other two bonds in the corner can stay for now. It may hold wire bundles or something later.

Here’s what I mean. You can see the bracket now sits higher and all is good.

You can see the Bus Manager happily sitting is space now. Its like a rock.

My bits are mounted just in the right spots for when the panel is in place.

This box is the GAD 29B to interface the GTN750 with the Garmin G3X. Yeah I think it should be all built in but Garmin likes lots of separate boxes I assume for different combinations of their products. I have it with click bonds and on the bottom of the GTN750 tray. It sits right next to the GAD27 box on the side wall.

This install is like a Chinese puzzle box simply due to putting a ridiculous amount of stuff in a small space. A side by side seating airplane would have a much bigger panel area. Sitting in the middle of the plane is fantastic so just a ‘minor’ issue for a big reward.

Date:  04-04-2020

Number of Hours:  20

Manual Reference:  22

Where to put the Bus manager? That’s the brain box for my critical engine functions.

While I came up with putting this above the GTN750 tray, a smarter person told me that its best to get those high amp lines away from the avionics. The back wall which I think is F22 became the ideal mounting place.

You can see more easily here. Its well clear of my feet and a few inches away from the radios. A good spot.

I was coming up with all sorts of mounting ideas using what I know. Greg, who also rents in the hangar, is a qualified expert in aviation sheet metal work. While I struggled to understand what he had in mind, it was cut and folded up by the time I got the concept.  Thanks Greg.

I checked the position with the canard on and found the VOR antenna right smack where the Bus Manager was going. A side step to the left (right in the pic) was possible.

I made up some nut plates and glued them into the Manager box for attachment points. At least I got that bit right.

Lots of time making beautiful and strong click bond mounts.

Now I have the box in place. BUT… on the right side in the picture my click bonds had to work around the canard attachment and the arm between the fastener and the folded edge is now too great. I am going to have to fix this.

All a part of working outside the comfort zone. That might be why I’m building this thing in the first place. ..but don’t quote me on that. Mistakes are also a PIA.

Date:  03-31-2020

Number of Hours:  30

Manual Reference:  22

The build stopped for two months and I’m back into it now every day as usual. The pause was while I achieved an Instrument Rating. That was full time with study and flying. After all, what good are all these expensive IFR instruments if I can’t legally use them and file IFR flights?

This instrument panel and component install is as usual death by 1000 cuts.

I have supported the big Garmin GTN750 tray with that piece of angle and click bonds. This sets the instrument panel angle and the beginning of a sturdy fit. The stick was while the flox set.

It has since been pointed out to me that I have the load (weight) in tension instead of shear. So I may revisit this with something on the side wall instead. <sigh>

The audio mixer didn’t seem to quite sit properly so I had to recut the slot. That was another full days work you can’t even see.

I spent a LOT of time fitting a back piece for the remote radio. Its the top left bit with the clamp on it.

Several days work getting that back strap fitted to take up the load of the panel. Pity about all that. I have since removed it as there was not enough clearance with just one of the plugs from a front unit. It took a full afternoon to undo the work.

Just a few of the things that still need to go in the panel area. Yes thats not all of it.

With the main display placed in position it was only then I realised that a plug below the fan WITH its connector was an issue. I allowed for the BNC antenna connect, but not the back case of a plug. Doh!

You’d never know the rear drama when you look at the clean simple front.

Date:  01-24-2020

Number of Hours:  20

Manual Reference:  22

Moving on with the Instrument Panel. My first version was in MDF, time for metal.

I’ve gone for 5000 series .125″ aluminium for my first proper metal attempt. Cheap as chips. It really is a bit too bendy so I may go for 2024T3 as the final. I’m pretty sure I won’t get this done in one attempt. With the final panel thickness I can set things up as if its the last version.

After fitting the panel to the plane I went with my MDF template to do the cutout.

I just covered it all in green tape to ‘practice’ protecting the metal surface. It’s also great for drawing on. Just a jig saw and files. That’s metal files. No CAD files for me at this stage.

It fits, more or less.

Here’s the angle idea left side.

…and right side.  Its down to around .8″ at the top compared to parallel to the bottom of the panel.

Apart from looking cool, I needed the panel sitting down at the rear so that the tray of the GTN750 fits. You might see how it would contact at the rear if the back end was higher i.e. straight instead of slanted at the front.

Now you can decide if the slanted back panel idea was a design decision first and a fit realization/necessity after, or the other way around. I’m not telling.

Just a note if anyone is reading this.

I am now doing my instrument rating which is around 4 days per week. The rest of the time I am studying a few things and mainly doing approaches on my home flight sim.  This is going to slow the build over the next two months almost to a standstill.  Given no word on an engine delivery date it is probably good to get the flight instruction I need now. Even better if I pass the eventual flight test, be it sooner or later.

 

Date:  01-16-2020

Number of Hours:  40

Manual Reference:  22

Another eight days went into just the mounting of three trays. First I had a small problem to fix.

Some months ago I had carefully floxed and glassed a tube to point the rudder cable towards the pedals. This meant it had to be about .25″ off the side wall. I really needed that .25″ back! The Garmin GTN750 wanted more space.

I spent quite some hours getting that tube off the wall, very carefully and with zero cable damage.

The tube was then re-fixed to the side wall after bending the metal. It will still be fine for the rudder and I had regained that little bit of needed space at the rear of the 750 tray.

This gives an idea of one of many ideas I have to utilise the space behind the main panel instruments.

Again lots of thought and I seemed to have a plan to mount a few trays.

Its heavy and clumsy but almost working. I was thinking I could cut and drill a lot of lightening holes. The mid tray needs to be offset so I can get the ADS-b unit out when I remove the G3X display. Trust me that things need to be maintainable within reason.

Nope, it was too ugly. I rethought and decided to use some composite skills and make a lighter rack holder for the top remote radio. Some aluminium sheet and two click bonds with glass did the job.

Now I’m much happier for this lighter and more elegant top unit solution. The rest was going in the scrape metal box as a fail. Oh… and there was another problem with it. The whole mount was about 3/8″ too much to the right, that offset was too offset,  and it contacted the auto pilot servo on the canard when I did a trial fit.

A couple more days work and I had this new idea of using .063″ sheet and small blocks instead of angle aluminium.

I went for proper nut plates and countersinking too.

It went together well in the end.

This is how the blocks work. Other ones were much smaller. I may drill holes in it later. I hate excess weight, on me and the plane. Both have too much.

Here’s the mount for the remote radio on top, the ADS-b goes in the middle tray and the audio panel tray is on the bottom and facing the panel. It is rock solid. Yes I know I have to make lightening holes and round the corners. Don’t try to suck me into doing it now. Every time I go early I find I should have left a bit of meat somewhere I didn’t.

For now, I can call this good and move on to a metal rather than MDF panel frame. I need to get really precise for the next part of the fit out.

 

Date:  01-07-2020

Number of Hours:  20

Manual Reference:  22

The panel fit out continues.

While this is just MDF board so I can see exactly how the panel display is going to work out. There are quite a few tricks to get the parts to fit so closely together. It took a couple of days to get here with some very careful work for something that will be thrown away. That’s the MDF panel, not the trays!

With proof of concept done I then worked on which switches go where. The two AG6 displays I can now see need to be separated. If they were together on the left as I had planned the panel material would have broken off with no thickness left.

The larger rectangles are bigger switch footprint for 10-15amp switches. I now have groupings with the lights below the main panel, engine functions and main bus’s to the bottom right and starter, fuel tank levels, emergency power, alt static and ferry filling right top.

Here’s how it looks in the plane, more or less.

These are only some of the box’s that will go in behind the panel. There are a lot more. I already know that my plans for above the GTN750 case are now changed. I think I have arrived at a way to do all this after spending most of the day trying ideas. Its much easier with things in your hand rather than doing it on paper.

When I put the panel in I found I could give it some angle backwards. Old school steam gauges often mean you need to keep things vertical. A vacuum driven artificial horizon for example will ‘topple’ at a slight angle. I’m a 100% glass cockpit so anything goes.

Here’s an idea of the angle I’m going for.

A look from the other side gives the idea. I will have more of the instruments shielded from the sun with a greater overhang. I’m liking the idea.

 

Date:  01-02-2020

Number of Hours:  25

Manual Reference:  22

The Garmin Avionics arrived 25th of November. Paying for them had me somewhat slow in unpacking the boxes due to numbness.

Yes all this is going in the nose of my plane. Insert your favorite expletive here _ _ _ _

Here’s the latest layout. I’ll do a full list in another post sometime. My point is there is not a lot of room.

This shot is a couple of years old but you get the idea its a long time planning and a lot of stuff to go in there. Yes the blue foam are actual sizes of the components that have to all fit.

The way to get this done is to start. We know the goal and the magic of ‘how’ will happen along the way.

We begin with the GTN750 (GPS), the Autopilot controller GMC507 and the main screen of the G3X. The audio panel, GMA350HC, goes below this. You can see the G5 on the right too.

I’ve started with these main three components. The ADS-b remote box will fit behind the big screen.

This might clarify the task. All I need are the boxes in place and then I just load up the components.

At this point I’ve given up working at home on the panel. While its nicer, all my stuff is at the hangar and I always leave something there that I need despite bringing home boxes of tools and then taking them back the next day.

I know you are not impressed but I am very happy with getting this far.

A huge amount of time and thought has gone into this arrangement. About 5 full days work.

Nothing is trimmed yet and I may change the aluminium to better quality. This is lightweight hardware store stuff. The cases are rock solid and lock together with final fixing in mind.

I will keep going but need to do a fit in the plane soon to see where I’m going to fix things from the sides and of course if the depth of the boxes is an issue anywhere. These installs take no prisoners.

 

 

 

 

 

 

Date:  12-22-2019

Number of Hours:  20

Manual Reference:  22

This is the install of the Garmin GMU11 Magnetometer. The unit need to be installed within 0.5 degrees of a cardinal point, within 3 degrees attitude of the plane in cruise, right side up and I would presume somewhere near level.

First up was finding  a line parallel to the aircraft center line. This involved the usual lasers, large set squares and plumb bobs.  Not to mention putting tape on the floor and drawing lots of lines.

The angle of the ruler above is in fact parallel to the center of the plane. A really smart person would have made the pocket opening in this orientation. A person with great vision would have foreseen the issues and the need to make the pocket wider and deeper too.. That’s not the guy building this aircraft.

With the requirement for no ferrous metals  I was working with brass screws, aluminium plate, extrusions and rivnuts. The problems of space, fitting it in and leaving screw clearances was significant,

While coming up with the above idea I did work on the bolt covers. I needed 4 covers for wings, upper and lower and two round covers for the spar bolt access. I found some sheeting, made a lip with a router and fitted all the bits. Just a side job while all this was happening. You can see the round hole cover beginning above.

OK so after more than 4 days work I got to the above configuration, put it in the cavity and had to call it. Epic fail. I got the orientation right but could not get within the needed 3 degrees of the cruise angle. That’s about 2 degrees nose up.

The next configuration was quite easy. I used some 3mm 6061T6 and riveted it to my plate after removing the other attempt. I have no idea why I didn’t see this working earlier. All the fiddling around had me better understand the clearance issues.

All done and I’m happy. On the left side in the pic you might see some aluminium washers. These allow me to angle the magnetometer up or down for my 3 degrees. If it needs a tweak I can add or remove washers. With the flat plate I now have room for this. The orientation to the center-line is correct. The unit is removable but it takes a little patience. We just need to wire it up.

Date:  12-16-2019

Number of Hours:  20

Manual Reference:  22-

The front gear of this aircraft is getting an automatic extend for the front gear as a fail-safe from landing wheels up.

Its a little laser.

The laser unit is a LightWare SF11_C 120m.  Its a device that senses the ground when it is 120m or about 393 feet away. If I haven’t already lowered the gear and if the plane is traveling between two set speeds, the gear will come down. Of course the laser just tells some yet to be assembled electronics in a box that its time to do something.

I need to mount this unit on the bottom of the plane pointing downwards.

First up I wanted to get a good clamping surface on the laser. I’ve since found out that they do make mounts for these things. I just assumed it was my problem. I started with some pour foam to get myself two flat surfaces.

I gave the laser a couple of plies of BID and then found some foam block off cuts with one side already glassed.

 

After a lot of testing and measuring for placement I had my laser mounted with hot glue and refined the fit.

The final mounting piece was glassed in and a base was added. A little foam will go on that later for a snug one screw fit.

While all that was happening I was working on a perspex window in my removable hellhole and RAM air cover piece.

This took some refining and worked out pretty well.

Here’s the laser in place. It is NOT a camera! Its a proximity laser OK?

Finally the ‘money shot’. Laser install for no drag penalty and easy access for maintenance if ever required.

Date:  11-16-2019

Number of Hours:  18

Manual Reference:  22-

Forward of the throttle I am putting six controls into the armrest. The two seat heaters, the pitot heat and oil heat and the two cooling fan switches. In other words this is my ‘heat’ area for the aircraft avionic controls.

First up I wanted the seat heater switches to be very close to the top of the armrest. This meant I needed to remove some foam and make a bed. Pretty easy.

I did a good job of making the switch mounts and epoxied them in place over night. That all worked out really well until I went to drill out for the switches. Too much force on the bracket and it failed at the wall. On to version 2.

Ignore the hot glue, this is a nice new bracket. A fraction wider so of course I had to cut into my simple layup, that should have been a few mm wider and deeper. Another over night cure.

Here’s my plan for this section. Pity that nice Ovation guitar knob didn’t work out . I’ll have to find something boring instead.

The bracket worked out except that it was a bit flimsy. I made the supporting piece you see above. It worked out about 1mm too high in the end but I have decided to leave it and round off a few corners. It is unnoticeable except that I just told you. I do want to finish and fly next year!

Oh and now you can see the interface box that I installed earlier.

On to the next bracket for the 4 remaining controls. This will sit just under the armrest and poke through. Its a weird shape as I’m going to rivet it to the existing armrest right angle piece as it just happens to be there. I could have ripped that out and made a single piece. Of course that would have needed other bits riveted too it so not much weight difference and probably another days work.

After quite some hours fiddling, especially the oil heater pot as it is so big under the plate and of course hard against the fuselage wall which needed a tweak.

Here we are done, except for a knob change. The switches are accessible but hardly protrude above the armrest as planned.

While not yet done you can see that armrest is busy!

Yes, I can put my arm down there and not notice all that stuff.