Sunday, 31 January 2010

The wings are on!

We fitted the wings today. I'll write more about it later and probably also post some video on YouTube. For now, suffice to say that once we'd worked out how to do it we had no real difficulties. Indeed we had both wings on by lunch time and so were able to go for a quick noggin and some much needed pub grub.

Many thanks to my helpers, Chris, Lizzy, Jim, Dave and Andrew. The picture shows Lizzy and Andrew sitting in the aircraft after the wings had been installed.

Friday, 29 January 2010

Final preparations

I spent a while at the airport again today, preparing for the wing mounting gang to descend on Sunday. With the starboard wing already in position, it was a simple task to connect up the fuel pipe and electrics. To help protect the fuel pipe, I enclosed it in some flexible plastic electrical conduit. Although there are no sharp edges for the pipe to rub against, it still seemed worth while to protect this particularly inaccessible area as much as possible before the wings are installed. For the same reason, I carefully wire locked the fuel pipe connections.

Next, I shrink wrapped each of the electrical connectors. This is partly for protection, partly to ensure that they cannot come apart due to vibration and partly to try to keep moisture out of the electrics.

Finally, I fitted the rubber sealing strip that runs along the underside of the wing, sealing it to the fuselage. Apparently this has quite a profound effect on stall performance. Slightly oddly, this seal is only applied to the underside of the wing, presumably because this is the high pressure area.

The rest of the day was spent with the somewhat fiddly task of fitting the Camloc fasteners into the cowling. The fasteners are held in place by a steel circlip, which is the very devil of a job to click into place. After a while I found a moderately effective method but nevertheless I have several broken nails from the experience. It must be said though that the aircraft does look rather swish with the cowling in place - it's a while since I've seen them fitted.

Saturday, 23 January 2010

Preparing to mount the wings

In preparation for mounting the wings, I spent half a day at Kirkbride today generally faffing around and checking things out. Firstly, I completed the aileron trim wiring and attached the wing tip navigation/strobe lighting units to both wings. I also fitted the aileron control rod fairing and inspection hatch covers.

With the assistance of one of the gyrocopter pilots, we set the starboard wing on trestles adjacent to the fuselage. I was then able to connect up all the electrical services (navigation lights, strobe lights, aileron trim and fuel level sensor). The lighting and fuel systems worked perfectly first time but the aileron trim needed a little fiddling with, due to a small error in the circuit diagrams. easily enough to troubleshoot and fix, but a little annoying nevertheless.

Next, using my digital vernier calliper I carefully measured the width of the slot that the wing main spar fits into on the fuselage. It was no surprise to find that the paint made the spar too thick, so I carefully rubbed it down using 400-grade wet and dry until there was just a very thin coat of paint remaining. I hope that this will be sufficient for the wing to fit snugly, as I really would prefer not to have to take the paint all the way back to bare metal, with inevitable potential for corrosion.

Finally, I fitted the Dzus fasteners to the wing lockers, together with nylon washers, which will help to prevent the paint from becoming scratched when the lockers are opened and closed. A further nylon washer on the underside stops the fastener from falling out when the wing locker door is open.

Apart from joining the fuel pipes, the starboard wing is now all ready for installation. I need to obtain a smaller trestle to support the inboard end of the wing, as the one I am using is too tall. I think a plastic saw-horse will be pretty well the perfect height (about 24 inches), so a visit to the local DIY emporia is called for before next weekend!

Friday, 22 January 2010

Finishing the cockpit

Today I was able to spend a while at Kirkbride working on the cockpit, in preparation for fitting the wings.

Firstly I at last finished the instrument panels and avionics. I had a number of minor wiring problems to fix:
  • Engine management system alarm light
  • Power to the magnetic compass for lighting
  • Rewiring the power and RS232 data stream from the GPS to the EMS
  • Shortening and properly terminating the various coaxial leads from antennas to the avionics
  • Generally tidying up all the wires and routing them to be out of view as much as possible
These  tasks took a surprising amount of time but the end result is a completely finished and fully functional instrument panel.

Next I turned my attention to the harnesses. The Sportcruiser has proper four point harnesses and the fuselage attachment points are difficult to get to when the wings are installed, so it made sense to install these today. The task turned out to be fairly simple and it's surprising just how adding the harnesses made the cockpit look more complete.

The list of tasks to be completed before I can fit the wings is slowly but surely getting shorter!

Saturday, 16 January 2010

Tidying up loose ends

I was able to spend a few more hours at Kirkbride today, sorting out various minor jobs prior to the all-important wing mounting ceremony.

Firstly, I fixed the slightly embarrassing problem with the trim indicators that I discovered last night. It turned out to be a simple wiring error - the circuit diagrams were correct but I didn't wire the display correctly. A simple matter to fix and it took longer to test than it did to redo the wiring.

I also completed the installation of the stall warning sounder. This is a loud piezo-electric sounder, actuated by a sensitive micro-switch on the port wing leading edge, which is actuated when the airflow breaks up due to excessive angle of attack (the cause of a stall). The sounder is mounted behind the instrument panel and it's very loud indeed! I don't think there'll be any difficulty hearing it, even when wearing noise cancelling headphones.

With that small job completed I was able to tidy up the rats nest of wiring somewhat, in preparation for finally mounting the three instrument panels.

Slowly but surely I'm clearing off all the jobs that can be completed prior to the wings going. I'm making tentative plans to have a wing mounting party towards the end of January.

Friday, 15 January 2010

Finishing the tail plane

I was able to spend a good few hours working on JONL today and used the time to finish off the tail plane. This is probably the last big job before fitting the wings, so I'm particularly pleased to see it completed. As expected (see earlier entry) I had to remove the horizontal stabiliser to fit the elevator trim wiring but that was straightforward enough. Like so many aspects of this build, when you've worked out how to do a job and done it once it is much much easier the second time around.

The trim cable was reasonably easy to fit. It is threaded through the stabiliser so that it pops out of the rear, adjacent to a hole in the elevator. A bit of fiddling soon had it routed correctly and, because it goes through lightening holes which have no grommets, I decided to put plastic pipe over the cable to reduce the risk of chafing. I then refitted the horizontal stabiliser and dressed the trim wiring before bolting everything firmly in place.

Next, I fitted the elevator. This turned out to be one of those truly awkward jobs, with very little room to work in and bolts that seemed particularly reluctant to slide home. In the end I managed to get all three bolts secured but not without a certain amount of cursing!

With the elevator fitted, I could now complete the trim wiring and test the elevator trim system end-to-end. To do this, I had to fit the P1 and P2 instrument panels in order to get power to the circuitry. The trim works OK but unfortunately I've messed up the wiring of the display panel because elevator movement shows on the aileron display instead of the one for the elevator! Fortunately that is easily fixed but I will also need to check on my documentation to see whether the error is there or in my implementation.

Finally, I connected up the elevator control rod and checked operation back to the cockpit. The job was then completed by fitting the fibreglass tail cone and the fairings around the horizontal stabiliser root.

So, a small electrical problem to sort out and, of course, I have to check the elevator control range but that is a job for later. Otherwise the tail plane section of JONL is now completed. Soon, very soon, it will be time to fit the wings!

Wednesday, 13 January 2010

Something is happening!

Hoorah! I was finally able to get to the airport and do a little work on JONL yesterday. With only a couple of hours available, I spent a bit of time familiarising myself with where I'd left off before Christmas and thinking about what I could usefully do with the available time.

In the end, I decided I'd try fitting the horizontal stabiliser. It's a tight fit onto a pair of steel locator pins set firmly in the rear fuselage section. Once in place (which takes a fair bit of pushing and shoving!) a couple of bolts hold it locked in place. The wiring for the elevator trim also passes through the horizontal stabiliser, en-route to the elevator. I didn't install that, although perhaps I ought to have done! I think I should be able to get the wire in without removing the stabiliser again.

Another tricky aspect of fitting the horizontal stabiliser is that there really isn't much clearance between the top of the stabiliser and the base of the rudder. It's altogether too easy to scratch the paintwork, or worse, dent the metal skin of the stabiliser. Moving the rudder to full deflection helps but it's still a bit of a squeeze.

Once the stabiliser was in place, I set the elevator alongside it on a pair of trestles to see how best to go about fixing it. Everything is quite close tolerance around this area, so care is needed to avoid bashing bits of elevator against the stabiliser. I'll need to sort out the elevator trim wiring too, before I can attach the elevator to the horizontal stabiliser.

So progress, albeit not a great deal. I hope to be able to get to the airport again on Friday.

Thursday, 7 January 2010

Nothing is happening

Nothing at all. In fact I am on other (non aviation) projects at the moment, waiting for this chilly weather to break. Even if I could easily get around - and that is far from certain, the roads around here remain treacherous - the hangar is far too cold for working in at the moment.

The picture shows the lane up to my home, which is at the top of the hill. It's not obvious from the photo but the bit by the oak tree on the right is really quite steep. Several vehicles have come to grief there recently!

There's no point cluttering up the Blog with nil progress reports, so my next post will be when there is something to report.

I'm staying put. I may be some time!