Saturday, 27 December 2014

Week 176 - Electrics Part 2

Hours to date: 1584.0

I've almost finished all the wiring work that I can do indoors - one more day should see it completed.

'Zip ties for Africa' on the back of the panel has tided things up a lot and made everything less likely to move around. 

The mess of wires has been cleared up a bit by the use of a nylon braid sleeve on the harnesses which protects them.

I made up the essential bus and bolted that in place in the lower panel/fuse box area. As it turns out I only needed one power source for the fuel pumps as only one can ever be run at any one time and my ON - OFF - ON single switch solution to this needs only the one power input to work.

I carried on with the fuse box section and fitted the starter switch relay and USB dual socket.

After that I made up the D-sub connectors for the UMA fuel gauges and then wired up the switches as much as I could. It turns out to be a blessing that I bought the twin pole single throw type switches as the access at the top to screw on the terminals is very limited by the gauges and starter switch above and with the two pole switches you get to choose which side to use.

There is only the audio alert rheostat left to finish off. This controls the volume of the audio alert from the Dynon D180 to the Radio/headset. The rheostat is not included with the Dynon which seems a pretty bad idea to me - this function should be controllable within the unit itself really. 

The audio alert is a pretty nifty function that allows you to set a limit for various engine outputs and if they are exceeded then you are given a beep through your headset - which makes for a lighter pilot workload and lowers the amount of engine gauge scanning you need to do.

Hopefully by tomorrow I will be finished these last few pieces of wiring and be able to head out to the garage and continue with the battery cable and other wiring installations out there.

I probably won't post again for a few weeks as I am off on holiday to Dubai and Oman for 10 days soon.

Have a great New Year everyone!

Slightly tidier back of panel with zip ties and nylon braid.


Essential bus - no need for 2 fuel pump power sources as I figured out later...

Fuse box getting sorted.

Essential bus in place and USB dual socket also shown.

Back of lower panel with switches wired up (mostly).

Fuel gauge D-Subs wired up.

Friday, 19 December 2014

Electric diagram updated

I'm hoping this version (v6) will be the last one!

The position of the Ammeter shunt has changed.

There is the addition of a capacitor over the battery.

The wires from the Rectificer/Regulator have changed position too.

The fuse value for the ECU has changed. 

Most of these changes are due to the UL Power installation manual being updated.

Updated wiring diagram

Thursday, 11 December 2014

Week 174 - Electrics

Hours to date: 1561.5

I've had a few days off work with the flu but this has let me crack on with some of the electrics.

It's nice to work inside in the warm for a change!

I began by wiring up the warning LEDs on the panel. Again these needed to be soldered - just when you thought it was safe to put away the soldering iron...

As you'll see I didnt make the neatest of jobs of this and even screwed up big time when the soldering iron lent on the ASI for a brief moment and melted it a bit! What a clutz! It didn't make a hole so hopefully it will be okay.

After that I switched over to the static and pitot lines. This ended up looking like spaghetti junction when finished. I've put some quick release fittings on the end of each of the main input lines so it is easy to remove the panel for maintenance at any time.

There is a mismatch between the Dynon and other gauges with regards to the size of tube used. 6mm (or 1/4 inch) on the Dynon and 5mm on everything else. I asked Harry Mendelssohn (the people I bought the Dynon, Transponder and Radio from) if they could chuck in a few extra 5 to 6 mm adapters which they did for free. I went for 6mm Tygon tubing with just the smallest amount of 5mm hose off the instruments themselves.

Regarding the battery cables - the original plan was to get them all sized up then take them to a local garage and get the crimps done - but I found a quality tool online for such a good price I decided to buy that instead. It is a beast with an 8 ton closing pressure and a big range of dies. 

Back onto the panel, time to tackle the EFIS, and EMS wiring harnesses. 

To start with I was a bit overwhelmed by all the complexity but as it turns out things are pretty straight forward and a good number of the wires are not used anyway.

First thing to do was check all the harnesses for continuity. My Multimeter has a tone function that makes this job easier as you don't have to look at the screen. As it turns out all the harnesses were perfect.

Second thing to do was establish which wires were not needed and trim them down. 11 were not needed on the 37 pin EMS harness and 6 on the EFIS harness. I've left enough length on them should I ever need to use them. I can put a butt splice on and extend the wire easily. The Dynon has a lot of extra functionality that a VFR type installation doesn't use.

After that I made up some labels and used clear heat shrink to set them in place.

The more work I do on all of this inside the less I have to do in the garage.

All that's left to do with the top part of the panel now is 'plug and play'. The EMS wires to all the sensors are the biggest thing left to do.

Next job will be moving onto the lower panel and most likely wiring up the switches, starter and making up D-sub plugs for the fuel gauges.

LED warning lights wired up with solder.

Other LED and the ASI with it's melted case!

Pitot and static lines

Line to Transponder will be connected later

Beasty hydraulic Battery terminal crimper

First crimp done

Testing the wires for continuity and correct pin placement

Adding labels with clear heat shrink.

EFIS harness with unused wires cut and bundled under heat shrink

EMS 37 pin harness - prior to labeling

Unused wires in bundle with heat shrink and cable tie

All done - what a mess!

Monday, 1 December 2014

Week 173 - Battery, Contactor and Headset jacks

Hours to date 1548.5

The headrest is all finished now - bar the painting.

Same deal with the thigh covers for the seat - again these need painting but the Dzus fasteners are all in place.

The firewall is also starting to get there. The Fibrefrax is all done on the front facing part - just waiting on the thinner Fibrefrax to do the outside of the fuse.

Onto the battery and so the start of the electrics - which I think is going to be a lot of work. 

I've got that '90% done, 90% to do' feeling...

The battery fits very snugly in it's mount and the same goes with the cover. 

I've figured out where I want the master contactor to go - and I'm starting to figure out the route for the battery cables.

The contactor needs a diode adding (this is to protect the circuit from the momentary reverse flow when the master switch is thrown). Easily done with a couple of crimps and some heat shrink. Remember to have the diode facing the right way! The grey bar on the diode goes towards the Batt (large pin) end. 

Regarding the location of the contactor - something I learned from my LAA electrics course is that in an aerobatic aircraft the contactor should not be mounted vertically. This is because under very high G the contactor internals can be driven downward so much that it switches off - thereby cutting all electrical power. This most likely happens at very high G levels which the Twister will never see but it is good practise to mount the contactor horizontally anyway.

Onto the headset jacks.

These seem the most archaic things in aviation - not available with a crimping style of terminal like everything else these days - instead you have to solder on the wires. This seemingly simple job took me a few hours as my technique was a bit crap with soldering. Got there in the end and I'm pleased with the result - don't forget to put the heatshrink on and support these wires well at the terminal end as they are quite fragile.

When is someone going to design a crimping style jack? There would be a huge market for them.

Next jobs are to continue on with the battery cable and other electrics.

Bottom of seat - showing areas carved out ready for 2 layers of carbon.

Fibrefrax all done on the firewall area.

Headrest all done. (Bar painting).

Underside of seat with Dzus fastener springs riveted in place.

Thigh covers all done - except painting.

Battery in it's mounting.

Battery with the cover on - very secure and snug.

Master Contactor location and first battery wire sized up.

Contactor with Diode added.

Headset jacks all wired up.