31st May 2011 - Finishing the lift struts

The lift struts had been cut to length and the top tack welded when the wings were first fitted to the aircraft Fitting the lift struts
However, the top end needed to be final welded and a supporting rap of 0.071" steel sheet cut and bent to fit to provide additional strength. This was a fairly long and tricky bit of work that I had been putting off for some time. However, a satisfactory result was achieved and the struts were test fit to the wings to ensure that the shoulders of the struts fitted properly into the brackets bolted to the wingspar.
Then the hinges for the left aileron and flap were cut and welded. As with the right wing a fillet of braze metal was run into the acute angle of the hinge to ensure that the joint was robust. You can see in the hinges holes drilled in what will be the top of the hinge - these will be used for lubricating the hinge.

12th March 2011 - Installing the stringers

The stringers provide support for the fabric covering of the fuselage and help create a curved shape. They are made from 1/2" aluminium tubing and are pop rivetted to the semicircular support tabs welded to the frame. This means that the outside of the tube that will support the fabric is completely smooth. There are three stringers along the top of the fuselage and two on the sides and bottom

28th August 2011 - English Summer

I've had little chance to work on the Tailwind recently but hopefully will now be able to get going again. I have managed to get a bit done over the last few months so will post a few updates to catch up on progress. The weather forecast for today said sunny periods in the morning with light drizzle from 16:00 onwards. This was the scene at 11:00 in the morning! I had installed the left wing to start rigging the flap and aileron when the "light drizzle" started. With the help of my wife and next door neighbour we got the aircraft covered and 20 minutes later the rain had stopped so no damage done but having to work outside is a bit limiting

4th March 2011 - Fitting the spinner

I'm waiting for some decent weather to do some painting so I took the opportunity to fit the spinner to the prop and prop extension. I had purchased a spun aluminium spinner "new old stock" intended for a Piper Cherokee 180. These are very expensive but I got this one at a good price. The problem was that the backplate and frontplate were cut out for a SAE #2 prop fitting and my engine is a SAE #1. I started by drilling a new set of SAE #1 spaced holes in the two plates using the CNC router. These were set 30 degrees out from the originals. Then the rivets holding the fillets underneath the propellor were drilled out and the fillets also moved 30 degrees, re-riveted and re-shaped to fit my propellor. The cut-outs in the spinner were also then shaped to fit and the spinner match drilled through the existing holes to the backplate. An additional 4 nutplates were riveted to the backplate and the spinner screwed to it. The existing holes were then used to match drill new holes in the spinner. This means there are now 8 screws holding the spinner to the backplate rather than the original four - should be stronger. Next the front plate was screwed in place in the spinner and the gap between the prop and the front plate measured. This was 8mm so a piece of 8mm aluminium plate was procured and a crush plate cut out on the router. A 1/8" aluminium spacer, the front plate, the crush plate the propellor and the backplate were then bolted to the prop extension and the spinner screwed into place. New holes were then drilled in the edge of the front plate through the existing holes in the spinner - again 30 degrees round from the originals. The original nutplates in the frontplate were then removed and re-riveted into their new positions. Finally the length of bolts needed to attach the propellor to the extension was accurately measured and AN bolts with drilled heads procured. These need to be exactly the correct length to ensure that the threads don't bottom but do show through the propellor lugs in the extension. The final job looks pretty good - a spun aluminium spinner for less than half the cost of the cheapest fibre-glass alternative. The only slight compromise is that the original cut-outs in the spinner were for the metal prop on the Cherokee and are about 1/4" too high leaving a slight gap above the front of the propellor. The sides and bottom are a perfect fit. I'll have a think about whether and how I could close these gaps for cosmetic purposes but they won't effect the performance in the air

20th February 2011 - Wiring Complete

All the wires are in and everything is tied up, tested and working. The panel was deliberately designed to be sympathetic to the generation of the Tailwind but provide good useful information to the pilot. The full specification is from top to bottom and left to right:
Starter engaged warning light
magneto switches
master switch
starter push button
digital compass
vacuum gauge
mode S transponder
tachometer
pilot headset
Airspeed indicator
Trio Easypilot autopilot head (away for service)
Location for Attitude indicator (vacuum plumbing still to be done)
Location for Directional Indicator
Primer
Altimeter
Vertical Speed indicator
Carb Heat control
Carb Temp, Oil Pressure, Voltage and Autopilot engaged warning lights
Multi-function display as described previously
Garmin SL30 Nav/Comm
King KMD150 GPS
Throttle and Mixture controls
Intercom
Oil Pressure and Temperature
Switched breakers for Nav lights, strobes, Fuel Pump and Autopilot
Cabin Heat control
Fuel Gauge
EGT and CHT gauge
Breakers for the Alternator field and Starter solenoid
Loudspeaker switch
Emergency power switch
2 spare 2-1/4" instrument cut-outs
Power outlet
passenger headsets
As can be seen in the pictures, the throttle, mixture and carb heat controls pass directly from the panel through the firewall. They will be final installed through the tubes installed in the fuel tank. In addition the primer lines will also go through the fuel tank. All cables pass over the fuel tank and then route under the floor to the rear of the aircraft or through the firewall as applicable. The routes through the firewall are protected with large grommets which themselves will eventually be protected with stainless steel shields and high temperature sealant in the engine bay.
looking at the firewall from inside the cabin, the main cable bundles are from left to right.
Magneto cables (kept clear of everything else to reduce possible interference), Comm and transponder antenna, instrumentation cables, GPS and Nav antenna cables, Main power lines, switched power lines (e.g. lights, strobes etc.)

14th February 2011 - One more wire and the panel is complete

The panel wiring is now complete with the exception of the wire for the "push-to-talk" for the radio where I'm waiting on more wire to arrive from Steinair. At the bottom left of the panel is the display for the remote digital compass. The aircraft wiring is complete except for cables for the right nav light, the strobe power, the push-to-talk and the remote compass sender.

13th February 2011 - Wiring

Work is progressing on wiring the aircraft. Most of the major cabling is now in and all of the cables through the firewall are in place and the engine and gear mount final installed - no pictures until I've cable-tied it all in!

One bit that is fully cabled in is the information panel I have built for the aircraft. This shows from top left to bottom right:
Switchable time of day or flight elapsed time derived from the GPS
Outside air temperature
System Voltage
Track over ground in degrees true (compare the magnetic track in the GPS display
Ground speed in knots
Carburettor temperature
Alternator charge current

In addition the unit flashes the voltage annunciator slowly for one minute and then illuminates it permanently if the system voltage drops below 12V. If the voltage rises above 15V the annunciator flashes fast warning that the voltage regulation may have failed and the alternator should be turned off.

The unit also controls the carb temperature annunciator which illuminates to show a warning between -5 degree C and +10 degrees when there is possible carb icing conditions. The other annunciators which are not controlled by the system monitor show low oil pressure and when the autopilot is engaged.