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Electrical & Avionics

Generally speaking this is being left until as late as possible. The electrical priniciples will be based on AeroElectric Dual Alt / Dual Battery design. More details to follow. 

Thu 09 March 2006

Other things today included finalising the Stein electrics order, hopefully we have got something close to what we need, all takes time however. 

Thu 20 April 2006

Dad did a number of 'bits' but started seriously looking at the ground straps for the FADEC / batteries. Looks like we were short shipped 2 long grounding braids from AeroSance - but shouldn't be a biggy.

Sun 25 June 2006

I had a slow / gentle day doing other bits, sorted a 12V DC power supply (8Amp) that I got a couple of weeks ago. I boxed it up added a fuse and a couple switches. Workes nicely...

Mon 26 June 2006

Spent a few hours doing electrical design work for the flaps and trim controls. Also got the HallEffect sensors running on the GRT EIS4000. The Aux4 input seems to be having problems - not sure why yet - hope I don't have a dodgy EIS. 

Fri 07 July 2006

It was a cold day outside and I wasn't in the mood for freezing in the shed. Therefore we ajourned to infront of the fire and continued with planning for the electrical systems. Lots of things at the moment are going slowly in actual progress, but lots of thought time. Hopefully this will keep the mistakes / dead ends to a minimum. 

Sat 08 July 2006

After yesterday's thinking time, the plan for the electrical ground layout seems to be coming together. We are currently planning on a chunky location on the rear of the firewall (that was today's fabrication) and probably a 'rear' earthing location for the Nav lights, Strobe pack and flap motor.

Thu 20 July 2006

Dad went shopping and got a large crimper - this will be used for the > AWG 10 cables on (mainly) firewall forward.
I made the main aft side grounding block drilling and soldered a couple of forest of tabs sets.
I just used standard soft solder, plus blow lamp, the screws were then trimmed and cleaned up on the back surface

Sun 23 July 2006

I was busy with other things, but Dad sorted the mounting for the centralised grounding straps.
The outboard bolts will have the engine grounds / battery grounds attached. We have also got a small set of tabs on the forward side, although we probably won't need that many.
And on the aft side, three bolt locations, the outer points will go to the FADEC harness and the mid bolt will go to the mid-ships ground point.

Tue 01 August 2006

Next is some of the heavy guage cables.
The battery terminals also needed a set in them to help with the routing.

Thu 03 August 2006

After much thought, ideas and bad options - this is where the main and secondary alternator feed circuit breakers are going. I'm still not convinced one way or the other on the merits of CB for the feed (vs. ANL on the firewall forward) but this seems to be the more 'common' method in NZ and a safe option.

Fri 04 August 2006

I also sorted a mini forest of tabs for the mid-ship ground point. It will provide a single GND for both the wings (landing / taxi / nav lights) plus central fuselage components (strobe pack, trim control etc).

Tue 08 August 2006

Short day - more thinking and planning. Also sorted the B always hot bus fuse block mounting - I need to get some longer #8 screws for here.

Sat 12 August 2006

I also made a mini ground bar for the mid-ship location. We are problably going for over kill, but everything is getting its own ground connection (ie. no using the airframe as a ground) and this will provide the strobe, wing lights, nav lights and misc control ground connections for the mid fuselage.

Mon 14 August 2006

I installed the new A/H - a little difficult with the fibre-lite ring and I ended up using both the supplied spacers. Also spent a bit more time on the annunicator layout / design problems.

Sun 01 October 2006

Slow progress with the wiring - main A fuseblocks wired up.

Wed 04 October 2006

I added a couple of studs to the circuit breaker bus bars and soldered them in and then continued with wiring and clamping various wire runs.

Fri 06 October 2006

The third iteration of the idea / bracket. Looks promising need to wait to work the cables / check final fitting.

Mon 16 October 2006

Dad completed two UHMW supports for the Hall Effect 'donuts' - these provide the AMP measurement points without the need to have a shunt in the line.

Sun 22 October 2006

Dad wrapped up some firewall forward routing / clamping.

Mon 23 October 2006

Dad worked on the avionics ground strap. We will have two tab straps and a DB9 connector in the middle, it is amazing how quickly we are using up the ground locations.

Tue 24 October 2006

The finished avionics ground strap, this was then coupled directly to the firewall ground strap.

Sun 05 November 2006

The majority of the day was spent working with the Hall Effect sensors. The default Scale & Offset factors (186 & 357) seems to be way out.

By taking a known current source (a landing light in this case = 6.4 amps) and measuring the volt output a better understanding can be gained - and calibrartion.

The 'measured' amps is then multipled up by passing the lead through multiple times. One of the first observations is the B side is linear upto and including the 13 passes (84amps) but the A side gets saturated at about 60amps. I not sure if this is just manufacturing variation or a 'bad' sensor - to my mind it is well outside manufacturing tollerances.

A table was then made for the measured values and I used Excel to goal seek the best fit number for the scale factor and then calculated the offset last. I also found the EIS can take 'big' offset and factor numbers, if you multiple up the SF / SO by 10 decimal values can then be used. My test results are below:

Turns	AMP	A Volts	Book A	Cal A	B Volts	Book B	Cal B
0	0	2.39	-1	0.4	2.39	0	0.4
1	6.4	2.62	17	6.8	2.49	7	6.8
2	12.8	2.85	34	13.3	2.59	15	13.2
3	19.2	3.08	51	19.7	2.69	22	19.6
4	25.6	3.32	69	26.1	2.79	30	26.0
5	32	3.55	86	32.5	2.89	37	32.6
6	38.4	3.80	105	39.4	2.99	45	38.9
7	44.8	4.02	121	45.4	3.09	52	45.5
8	51.2	4.23	137	51.2	3.19	59	51.6
9	57.6	4.49	156	58.4	3.29	67	58.0
10	64	4.72	173	64.7	3.39	74	64.3
11	70.4	4.74	175	65.2	3.49	81	70.6
12	76.8	4.74	175	65.2	3.59	89	77.2
13	83.2	4.74	175	65.2	3.69	97	83.7

Factor			186	688		186	1602
EIS Offset		357	1305		357	3057
Offset			-179	-652		-179	-1528
For reference the equation is: Result = (Value * ScaleFactor / 2.5) + ScaleOffset So we have 'an option' but the A side is still a concern.

Mon 13 November 2006

I removed the left tray and drilled / fixed the WingWag and fuel pump relay.
I've been trying to sort locations for all the electronics boards, I was hoping the right hand tray would be big enough but not so. The new plan is to mount the dimmer controls on the LHS behind the MFDs.
Then after some testing / learning, power and ground cabling. We were going to use a seperate switch control for the dimmers, but the minimum load is only about 30mA so I've decided to just tag the dimmers onto the nav lights switch.

Sat 13 January 2007

Dad did some tidying up of electrical stuff and mounted the hall effect sensor - works well after all the effort / thought.

Sun 14 January 2007

Sorted the CB boots for the 40 and 60 amp alternator feeds. Also remounted them with new shakeproof washers.

Wed 17 January 2007


Thu 18 January 2007


Tue 23 January 2007


Wed 24 January 2007


Fri 25 May 2007

Also positioned and connected the primary alternator.

Tue 29 May 2007

Sorted the firewall Oil Temp / Pressure connection.

Tue 31 July 2007

An additional fuse / supply added for the EDU logging unit. This is the B bus mini fuse set.

Thu 30 August 2007

I reworked the ground return from the pitot heat and added the read relay switch. This will sense current going through the pitot heat, rather than just the fact that power is being switched.

Fri 31 August 2007

Pitot reed relay finished and tested - works well.
Carl Morgan