29th September 2008 - Instrument Panel and Combing

The objective today was to fabricate and mount the blank instrument panel and fabricate the combing. The first picture shows the panel blank cut out of 0.090" 6061-T6 aluminium sheet and clamped to the mount installed yesterday. The size and shape of the top of the panel was designed to provide the maximum panel real estate whilst not limiting visibility out of the front or side windows when the aircraft is either on the ground or at flying attitude. A dummy combing was made from bits of scrap hardboard hinged at the folds with duck tape to provide a template for the 0.050" aluminium sheet used to form the actual combing. This was cut out and folded. Then a length of 3/4" * 0.063" right angle alumium extrusion was cut and riveted to the inside of the combing to provide the support for the top of the panel. The panel was then match drilled to the combing angles and to the tabs on the panel mount tubes. Finally, two pieces of aluminium were fabricated to close the gap between the ends of the panel and the door posts. These were match drilled to the combing and to the panel and riveted to the combing. That makes a full days work sound easy whereas it was a actually matter of repeatedly iterating the size, shape, and folds in the various components to get a good fit. At the end of the day I'm pleased with the result. Next I need to install the tabs to fasten the front and sides of the combing and install nutplates to take the screws that will hold the panel in place - that will also take longer to do than say!

28th September 2008 - Panel Mounting, tabs 128-143

I'd been considering how to mount the panel for some time as the plans give no information on this. Looking through the various Tailwind pictures on the web, some people were clearly using welded supports rather than aluuminium brackets so I decided to adopt this approach. 1/2" * 0.035 tubing was used to fabricate the lower mount which has tabs on 2.5" centres and stands back 5.5" from the door - the one dimension called in the plans. The vertical position of the mount is determined by the requirement for the control column to have clearance under the panel for full forward position. The lower mount will provide both support and stiffening for the bottom of the panel which will ensure that the various switches and in particular the engine controls are secure. Two short sections of the 1/2" * 0.035 tubing were then welded to the inside of the top stub longerons that form the bottom of the side windows. These were terminated with tabs to mount the top outside corners of the panel. The top of the panel will be stifffened and supported by extruded aluminium angle riveted to the panels forming the combing which in turn will be mounted on tabs welded to the same stub longerons and also the firewall top cross member - I think....

25th September 2008 - Seat surrounds

It has been a late start to the building this week as a result of a serious "man-cold". However, a bit of sunshine today tempted me back into the workshop to try and finish up the surrounds for the seats. First I fabricated the right side panel and then a panel for between the seats. Tabs 123-127 were then welded into place and match drilled to the panels and the usual clinchnuts inserted and tack welded. Then the sections of the armrest/flap lever cover were deburred and the top panel coutersunk for AN426-4-4 rivets. These were back-riveted into place which leaves a clean top surface ready to take a covering yet to be decided. Basically this completes the seating and flooring of the cockpit. The only bit I haven't worked out yet is how to fill the gap between the door posts and the seat sides. It probably doesn't need doing all the way up but the bottom section is essential to stop any loose items like pens disappearing into the back of the fuselage.

19th September 2008 - Seats and flap lever housing

The seats have been designed to use the same size backs as the Vans RV9A and I had some foam left over from the Vans so with the purchase of a little more to complete the side bolsters and some three inch extra-firm for the seat bottoms I could construct the complete seats ready for upholstering using spray adhesive to stick the bits together. Foam is easy to cut accurately using the bandsaw but there are also firms that will cut it to a wide variety of shapes at very reasonable cost (in the UK http://www.efoam.co.uk/ are great). Then I cut and installed a fill piece of aluminium between the front of the seat bottoms under where the flap lever sits in flaps up position. This was cut out for the centre tube to ensure that the maximum clearance from the flap lever was maintained. Next I cut out a paper pattern for the sides of the flap lever housing. The front curve is an arc centred on the flap pivot. The top of the housing is designed to be horizontal in normal flight attitude and will be padded as an armrest. Two pieces of aluminium were then cut and folded to the pattern remembering to make mirror image parts. Then a slot for the flap lever was cut in an aluminium strip to form the top of the housing and it was match drilled to the sides and clecoed into position. Finally, the seat foam was replaced to check clearances. The flap lever housing and the side panel nicely locate the seat bottom. If things work as planned the slot for the flap lever will be filled with brush style draft excluder to make a neat finish around the lever but allow free movement. Next I need to debur and rivet the flap lever housing and I've still a side panel to make for the right side of the aircraft. Still, I'm pleased with progress today.

18th September 2008 - Left rudder cable cover

Just a limited amount of progress today. The routing of the rudder cables takes them through a cut out in the outer edges of the seat bottoms. To keep them out of the way a cover was fabricated and riveted to the seat bottom and screwed into tabs 120-122 welded onto the side rail that forms the bottom of the door frame. This provides a neat solution to locating the seat cushion and avoiding any risk of the rudder cable fouling.

17th September 2008 - Seat Backs

Well it is back to building at last! Today I fabricated the seat backs. Like the floor these are made from 0.050 6061-T6 aluminium with the edges folded up for stiffness using the bending brake. I'd been puzzling for some time how to fix these such that they were easily removable. My initial idea had been to use hinges with removable pins like Vans at the bottom but this still left the issue of how to fix them at the top. Luckily, my next door neighboor Daryl was passing while I was pondering and immediately suggested hanging them from the cross members - brilliant! So I fabricated a U-channel to fit over the top cross member from two pieces of extruded 3/4" right angle. The first section was riveted to the back of the seat using countersunk rivets and then the second piece match drilled to it to give a good fit over the cross member. This was then riveted to the first section. Then two pieces of 0.063" aluminium sheet were cut out to fit over the lower cross member and riveted to the sides of the seat back. Together the two hangers locate the seat backs securely whilst allowing them to be easily removed. The seat backs were designed to take exactly the same size foam as my Vans RV9A which will allow me to use the same fabric patterns as I used for upholstering the Vans. The seat bottoms will then be 3" thick foam which should be nice and comfy and provide protection against any hard landings.