Thursday, 31 December 2009

December in review

A disappointing lack of progress during December. The weather is to blame - it has been dire. We've had snow on the ground since the 20th and the temperature has hardly been above freezing since the middle of the month. Travel is difficult as I live on top of a steep hill and the road is never treated, so it's like an ice rink. But, truth be said, it has been much too cold since mid December to spend significant time in the hanger-cum-workshop.

Some progress was made. I more or less finished the instrumentation and that's just waiting to be finally installed. I also fitted the BRS and the instrument coaming, ready for the instrument panels. A fair amount of work has also been done on the documentation.

I'm working on other things while this cold weather persists. I have a large software project relating to my amateur radio hobby that I'm getting my teeth into and that means hours sat in front of computer screens trying to out-logic the machine. At least it is warm in the house!

Let's hope the weather improves soon and I can resume working on G-JONL.

A happy new year to my Blog followers.

Friday, 25 December 2009

Season's greetings

A very merry Christmas and happy new year to all my Blog readers out there in cyberspace!

I know you're there, because although most of you post very little here on the Blog, I do get the occasional e-mail and comments on the Sportcruiser reflector. Please don't be shy - I welcome comments here and will always try to reply to them where appropriate.

2010 should be the year that G-JONL flies. I look forward to sharing the experience with you all!

Thursday, 24 December 2009

Document library updated

I've updated the document library with all the latest documents. There are no new documents as yet, only updates to existing files.

There are many changes to the electric circuits and associated schedules and I think I should be getting fairly close to the final documentation set here, as the instrument panel is all but finished.

I've substantially updated the POH but this is still very much a work in progress and will be until the aircraft build is completed, weight & balance schedules have been prepared and so on.

Monday, 21 December 2009

Wing mounting pins

This evening, just as it was getting dark, Postie arrived bearing, inter alia, a pair of wing mounting pins, previously believed to be lost in a snow drift. I have to say I was quite surprised that Royal Mail delivered today - the roads are quite treacherous, as I discovered myself when I ventured out in search of milk and, importantly, supplies of wine for the festive period.

Anyway, another part of the project slots into place and I can now get on with mounting the wings on G-JONL when the weather improves a little. Many thanks to Graham Smith, the former agent for Sportcruiser in the UK, for lending me his wing pins. Graham's support has been excellent throughout the project.

Saturday, 19 December 2009

It's too cold...

... to be messing around in an unheated hangar on a windswept airfield in Cumbria! Last night the temperature at home dropped to -7°C and it's not got above freezing today, with only a couple of hours of daylight left. It's alleged that we shall have snow tomorrow, which will make the place look pretty but do little for any prospects of heading to the airport!

So I am stuck at home, tidying up odd bits of documentation and generally pottering around. I'm also waiting for a set of wing hanging pins to arrive, courtesy of Royal Mail, so that's a half way decent excuse for staying at home. I suspect that this cold snap is going to continue until after Christmas, so it looks like it'll be the new year before the wings are finally attached.

Brrrrrr!!!!

Update: 21-Dec-09 at 14:30

Sure enough the snow arrived and very pretty it is too. So far we've got about 12cm of the stuff chez tWF but there's more to come, looking at the weather radar. I cannot recall having substantial snow this early in the winter season. Certainly not in the nine years since I moved to Cumbria. So much for global warming!

It looks like this cold weather is set to hang around for a few days yet, so it'll be after Christmas before I can make any further progress with the build. The wing hanging pins haven't arrived either... I suppose they are stuck in a snow drift somewhere.

Update 24-Dec-09 at 14:30

Well we still have the better part of a foot of snow here at tWF Towers so I'm not going anywhere. The next few days are occupied with seasonal festivities, so it's probably going to be 2010 before I can get up to the airfield again. Not to worry... this never was a project that had to be completed in a specific time scale and I reckon I should still be game on for flying by Easter.

Meanwhile, we've got snow on Christmas day to look forward to. I think that may be a first for me. I shall enjoy looking at it from the warmth of my living room with a glass of hot mulled wine in hand.


Update: 02-Jan-2010

Yay! A new decade but it just ain't going away, this snow. We had another couple of inches of the stuff last night, just as I was starting to think the local, untreated roads might become passable again soon. I have now, officially, had enough of snow, thank you.

Today I spent an interesting hour digging my neighbour's car out of the side of the road where he'd slithered diagonally across the road and into the hedge. Even with a lot of shovelling and pushing, we couldn't get his car up the hill past my place. Eventually one of the local farmers came by in his tractor and that got us moving all right!

So I guess I'm still going nowhere for the time being. The weather forecast is dire for at least the next week. At this rate I'm going to lose a whole month to the weather. And that after all the problems with flooding in November.

Frustrating!

Wednesday, 16 December 2009

Fitting the coaming

Although I've temporarily fitted the instrument coaming (the glare shield, for our American cousins) on many occasions already, yesterday I finally screwed it into place with some 25 screws. It certainly isn't going anywhere now! On the other hand, if I need to remove it, for example to access the ballistic recovery system parachute or to provide easier access to the firewall area, then it is just a matter of unscrewing all those screws again!

Before I could fit the coaming, I needed to install the magnetic compass and GPS antenna, both of which sit on top of the coaming. This involved wiring - power for the compass illumination and the coaxial lead for the GPS antenna - together with some careful hole drilling. Another place where measure twice drill once was the order for the day.

It turned out to be a bit of a challenge fitting the coaming. Firstly, the leather covering does not drill well. The leather tends to close up once the drill is removed, making it difficult to get the mounting screws through. In the end I cut away the leather around each hole using a sharp Stanley knife and that fixed that problem. It also turned out that some of the pre-drilled holes didn't line up with their partners in the canopy surround, so some judicious filing was needed to "move" the hole slightly in the coaming.

With those problems solved, it was a comparatively simple exercise to finally fit the coaming. I wonder how long it will be before I have to take it out again?

Today, back at home, I completed the alarm LEDs wiring. This little bit of electronics comprises a pair of LEDs (Unsafe and EMS alarm), a couple of resistors and a bunch of diodes. I built the whole ensemble on a small piece of Veroboard, which is held in place behind the instrument panel by the LEDs themselves, together with a small plastic screw to stiffen the mounting.

A few tests show that it's all working (there isn't much that can go wrong really) and so that is another part of the instrumentation complete. Indeed, I now only have two or three minor bits of wiring to do and all the instrumentation will be completed. I hope to get up to the airport on Saturday to finish the job and then I'll be onto the flying surfaces. Deep joy!

Saturday, 12 December 2009

Yet more instrumentation

There's no doubting it, the instrument panels are a big part of the project. I have been continually surprised at a) how complex it all is (probably largely my fault!) and b) how long it takes to do seemingly straightforward bits of wiring.

Well things are rapidly heading to a conclusion now. Over the last few days I've been systematically working away at the remaining jobs and there is now very little that has not been completed, tested and deemed (by me at least) to be satisfactory. I've also completed end-to-end testing of most systems, including the avionics, flying and engine instruments. Although most of these subsystems had been tested before, in isolation, this is the first time I've been able to fit everything together and check out the whole lot.

There have been a few issues to resolve. I've decided that I hate modern BNC plugs (used for the antenna connections) with a quite unreasonable vengeance. They are notoriously difficult to make a good reliable connection with. It is increasingly difficult to procure the altogether better (but more costly) plugs that have a nice ferrule for the coax outer. I must try harder, for I have had to remake two connections so far due to the inner conductor not making contact with its mate on the radio socket and, instead, trying to short out against the outer. I've also had to fix a short circuit that was popping one of the contact breakers. That turned out to be a power wire that had worked loose and was making contact with the radio chassis.

Anyway, with the BRS installed and the instrument wiring all but finished, I am very close indeed to finishing off the cockpit, so my attentions will soon be turning to the wings and tailplane. In preparation for which, we yesterday rearranged the hangar somewhat to give me a bit more room. Wings on by Christmas? Perhaps not, but it's getting close now.

BRS installed

In hopeful anticipation of approvals in the near future, I decided to complete the installation of my Ballistic Recovery System. Actually, as this is a factory fitted option, it was only really necessary to reinstall it.

I was particularly keen to ensure that the BRS installation does not interfere with the avionics stack. Things are a bit tight in there but it turns out that there is enough space - just. The BRS rocket must have unimpeded egress, straight up through a frangible cover on the fuselage, immediately aft of the firewall. The rocket then pulls out a small drove 'chute, which in turn pulls out the much larger main canopy. The main canopy is attached to a 10ft bridle, which in turn pulls out the four support bridles, one in each corner of the cockpit, in effect.

All this paraphernalia has to be able to exit through the hole created by the rocket knocking out the frangible cover! In practice, once the drove parachute is out, nothing much is going to stop remainder of the system deploying, as it is now being pulled with the weight of the aircraft plus any deceleration forces. The critical considerations therefore are to get the rocket and drove 'chute out unimpeded and then make sure that nothing structural can get in the way of the remainder of the system deployment.

It turns out that this is all relatively easy to assure. The rocket pulls directly on a short steel lanyard, which in turn starts pulling the parachutes out of the pack, which is alongside. Once the parachutes are out, all the bridles just pull through (they are fixed, zig-zag folded, alongside the parachute pack. I don't doubt that in the process of pulling through a few electrical wires would be damaged but that is as nothing compared to what happens next!

As the main bridles deploy, the two rear support cables have to pull through the canopy surround from the front of the canopy right to the back so that the rear cables and bridles can rise vertically to the parachute. If this were not to happen then the parachute would be holding up the front of the aircraft only, so it would descend tail down.

So the upshot of all this is that substantial damage, probably sufficient to write the aircraft off, is done even before it reaches terra firma. The BRS then is a facility of absolute last resort, for use if the aircraft has been fatally damaged and is fundamentally incapable of flying. It's not for use just because the engine has stopped!

That said, I was presented with an interesting conundrum on this very point by one of the guys at the airport yesterday. What about if the engine fails over water and there is clearly no way to make it to land. Pull the parachute? My initial response (which probably still remains after reflection) is that one would not. But conversely, a ditching is virtually certain to result in a write off and with the fixed undercarriage there is a considerable risk of flipping the aircraft on its back during a normal landing, making escape from the aircraft difficult if not impossible. At least the parachute ought to bring the aircraft down the right way up. Hmmmm....!

Tuesday, 8 December 2009

BRS

One of the things that has concerned me for some time is the ballistic recovery system (BRS) that came with my kit. It was the first and may still be the only kit in the UK with this option, with the result that approvals have not been granted. In LAA-speak, the option is not included in the Type Acceptance Data Sheet (TADS).

This has been giving me something of a headache as without the approvals the BRS cannot be fitted but by its nature its components cannot be entirely removed from the fuselage either. Some months ago I started applying pressure to have the matter addressed, both to the LAA and to the new importers. It seems that at last progress is being made. As a result, I decided, for the time being, to proceed with the expectation that this factory fitted option will be accepted and written into the TADS in time for my flight trials programme.

Over the past couple of days I've been working towards that goal. Firstly, I completed the mounting system for the coaming, using rivnuts and demonstrated that the coaming can be easily installed and removed. This is a major advantage, in particular because it makes access to the BRS components so much easier.

I took lots of photographs of the mounting system for the BRS, as I am sure these will be required by the LAA. The BRS has long parachute bridles that have to be folded, zig-zag fashion and secured to the fuselage, just aft of the firewall. It's a little fiddly getting these arranged in such a way that they will correctly deploy in the event that the BRS is activated.

One problem is the proximity of the avionics stack, which protrudes sufficiently far forward that it gets rather close to the parachute mounting tray. An official solution is at hand fortunately, which permits a small section of the tray to be cut away. This I have done and there is now good clearance all round.

I'm now almost ready to install the BRS rocket and parachute assembly. I may just wait a day or so to see whether the promised progress actually materialises!

Friday, 4 December 2009

More instrument panel work

I've had a couple of very productive days at the airport interconnecting all the various instrument panel electrical services. Slowly but surely the rats nest of wiring that has been adorning the central console and panels area on the fuselage is getting married up to similar spaghetti on the panels themselves. This sounds like a recipe for even more of a mess but in fact the contrary is true - as each service is integrated, straggling wires are becoming tidier and fewer in number.

Yesterday I did a lot of the preparation work, completing the wiring of the P1 and P2 panels and looming everything together to make it tidy. Today I integrated the two panels firstly with each other and secondly, with the fuselage wiring. One by one the various services have been connected up and by the time I left the airfield this evening, almost all the electrical systems were operational.

I also started integrating the already completed avionics panel into the instrument cluster. Most of this has been tested before and the principal additional work was to organise power to the avionics via the panel switches and contact breakers. That work is not yet completed but an hour or two tomorrow should do the trick.

There are still a few ancillary services to integrate, including power to the stall warner, the landing light wiring and the alternator control circuitry. And I need to implement the emergency power supply system that I discussed a few days ago. None of these are big jobs, so I think there's a good chance that I'll finish the instrumentation tomorrow. Then it'll time to get the engine ready for starting!

Wednesday, 2 December 2009

Instrument panels & coaming

At last I was able to spend some time at the airport today.

I completed the other instrument panel trestle so now I can put the P1 and P2 panels in place without having to install the coaming (the glare shield to any Americans that may be reading). This will make it much easier to complete the wiring, of which there is lots.

I decided to have a go at fixing the coaming and instrument panels, in order to check out whether there are any problems. Normally the coaming is attached to the fuselage with about 35 rivets but the problem with that is that once fitted it is very difficult to remove, should the need arise in the future. So I decided to experiment with rivnuts instead. These are, effectively, threaded blind rivets. They are installed like a pop rivet but instead of a mandrel a screw thread is used to pull the rivnut. Once the rivnut is pulled, the tool is unscrewed and from then on an ordinary screw can be used.

It turns out to be a bit fiddly to get the coaming all aligned so that the screws can be inserted but otherwise the rivnuts work just fine. Even with only half a dozen installed the coaming is very secure. This has got me thinking that I could leave one or two holes on each side without a rivnut and it would then be quite easy to use some cleckos to position the coaming ready to screw in place. I'll need to experiment with that idea some more.

With the coaming in place, I was then able to install the three instrument panels - P1, Avionics and P2. This is the first time all panels and all instruments have been installed and I have to say I think it looks rather good! Particularly pleasing is that there are no show stoppers. Everything fits together nicely and there should be plenty of room for all the cabling and so on. It will still be much easier to do the cabling without the coaming in place though, so the trestles will definitely see some use over the next few days.

Finally, with not much time left before I had to leave the airport, I decided it was about time to start constructing the propeller. The three-bladed prop comes with each blade as a separate unit and a big cast aluminium boss into which the blades fit. Eventually I will have to align the blades to precisely the same pitch (approximately 13°) but that is a job for later, when I've worked out how to do it! For the time being it was sufficient to mount the blades and then attach the prop to the engine.

Hopefully I should be able to spend the next few days working on the build project and start making some serious progress at last.