Thursday, 30 April 2009

The first month in review

It's almost a month since I was given the go-ahead by Tom, my LAA inspector, to start my build project. So how's it going?

Well, it's been a bit of a slow start! I seem to have spent inordinate amounts of time trying to work out what I need, sourcing, purchasing and receiving deliveries. Considerable time has also been expended on documenting and generally thinking about the project, whilst relatively little actual work has been done.

Does this mean the project is not moving forward? I don't think so. It's tempting to wade in and show visible progress early on but often all that happens is the work has to be done again or, worse, some stupid mistake creates yet more work and/or cost.

So I think I am essentially content that I've spent most of the first month planning and marshalling resources rather than drilling holes and bolting things together. I think that the next month will see rather more evidence of progress and I am hopeful that it will be swifter for having taken my time this month.

There is one minor item of work completed that I should report for completeness. I've finished building the control sticks, adding the stick grips and electronics for trim control and the radio press-to-talk buttons. Both seats have full control so the aircraft can be flown and fully controlled from either the P1 (left hand) side, usually the aircraft commander's seat, or the P2 (right hand) side, which is where the passenger usually sits.

Total project time is now 48h 00m but that takes no account of all the hours spent at home planning and drawing up spreadsheets!

Monday, 27 April 2009

Electrical stuff

I realised fairly early on that electrical systems would be a major part of the overall project. Not only that but it is arguably where the builder has the most flexibility in his design and the least guidance. Most of the mechanical build can necessarily only be done one way, with little room for individualism. Not so with the electrical systems! Just as well, then, that I have electronic engineering credentials.

I've spent many happy hours sketching out circuit diagrams and trying to work out where various items of electronics should be positioned in the aircraft. Sometimes this is obvious but often placement is a compromise between factors such as length and complexity of wiring, ease of access, interaction with other aircraft components and so on.

Inevitably there are lots of connectors and vast numbers of wires and cables, so I spent a long time thinking about the best way to catalogue these items. In the end, I've settled on two schedules in addition to the normal circuit diagrams. A Cable schedule will contain details of every wire or cable in the aircraft and a Connectors schedule will similarly catalogue every plug and socket. Together with detailed circuit diagrams, this should provide a fully documented record of the aircraft electrics/electronics.

I did do a bit of work on the aircraft as well. I've run some multi-way cables into the wings and fitted connectors to the aileron trim servo. I also spent some time experimenting with the instrument coaming, to help me understand how the instruments will look when completed. That has turned up a few issues that I need to resolve soon, especially the unfortunate fact that I can't get all the avionics I want to fit into the central "Avionics stack" panel. I do have a cunning plan...

Total project time is now 44h 30m

Thursday, 23 April 2009

Gone a bit quiet

Golly, almost two weeks since I last updated the Blog! I have been making some progress but I've also been busy with other things, having welcomed a number of visitors to the sunny Eden Valley and also made a couple of trips away. I've also done some flying in my Warrior, enjoying the excellent weather we've had up here recently.

Enough excuses! Mostly I've been working on the design of the electrical system and looking at instrumentation. This is a big part of the overall build and some parts of it certainly have to be designed and implemented relatively early on in the project. For example it is much easier to lay cables in the fuselage when it is partially de-skinned. Although I have no immediate plans to rivet up the fuselage, it won't stay open for very much longer, if for no other reason than the risk of accidentally damaging the loose panel.

I've also de-skinned the other wing and inspected it. This is a bit more complicated as it has the Pitot and static pressure lines. I'm also contemplating putting a stall warner on this wing. Both wings, of course, have strobes and navigation lights to be installed and connected up... more electrical engineering to design.

It's probably true to say that the aircraft electronics is the least structured aspect of the project. There is virtually no documentation and much of it is up to the whim of the constructor. As an electronics engineer, I should relish this freedom, even though it does seem a little daunting at the outset!

Sunday, 12 April 2009

What's in the wings?

Yesterday I made a start on one of the major phases in the Sportcruiser build - working on the wings. The wings come essentially fully built from the factory but it is necessary to remove the ailerons, flaps and the composite wing tip, each for separate inspection. Then the underside of the wing has to be de-skinned by drilling out about 50 temporary rivets. This work took well over an hour to complete on the starboard (right hand, looking forward) wing.

With the temporary rivets removed, it is possible to see more or less the entire innards of the wing. The fuel tank is clearly visible as are the fuel and tank venting lines. Wires run from the fuel gauge sensors to the wing root and there is a plastic pipe for wiring to be installed for the aileron trimmer servo and for wing tip strobes/navigation lights. All these will have to be installed before the wing can be finally reassembled. On the port (left) wing I'll also have to deal with the pitot and static pressure sensor piping.

The wing is such a critical part of the airframe that it has to be inspected by the LAA inspector before it is riveted up. The plan is to get several of these inspections lined up (both wings, the fuselage, etc.) and have the inspector come down to do the lot in one visit.

Total project time is now 33h 45m

Friday, 10 April 2009

Fitting the rudder pedals

Over the past couple of days I've been doing what I hope will turn out to be one of the more difficult build tasks: installing the rudder pedals. This is a singularly awkward job that involves lengthy periods of time spent flat on your stomach, grovelling around in the foot-well underneath the instrument panel. Of course there is no instrument panel yet, which is probably just as well. By way of preparation, I rehearsed the installation on my workbench.

My friend Chris assisted with the initial installation work, which requires two people, one outside the aircraft doing up nuts underneath the fuselage and the aforementioned contortionist (me!) in the cockpit, lining up all the bits and pieces. That was the easy part! After Chris had gone, I set to installing the hydraulics for the braking system and various levers and cables associated with the rudder. This is nearly impossible in the space available and it took much scrabbling around and trials before I could find a way to complete the work. I have bruised knees, elbows and knuckles to prove the point!

We also moved the starboard wing into a separate area where I can start working on it. This by comparison with the rudder pedals was easy work indeed. I removed the flap and aileron without too much difficulty and carefully inspected them for any imperfections. None found. The next stage is to de-skin the underside of the wing to inspect its internals and to install the many electronic and mechanical services that a modern wing carries.

Total project time is now 30h 15m

Tuesday, 7 April 2009

Fuselage revealed

Yesterday I removed the temporary rivets on the starboard side of the fuselage to permit an internal inspection. This is required by the LAA in order to check the riveting and general structural integrity of the fuselage. It also provides a useful opportunity wire up the antennas and other stuff that will be quite hard to get at once the fuselage is all riveted up.

I must say the internal structure seems very clean. All the rivets are nicely lined up along the centres of the bulkheads and longerons. I took the opportunity to remove the rearmost elevator push rod as this is said to make it easier to install the rudder later on in the assembly process. It must be said that this looks to be an impossible task! I think I shall have to engage the services of a youngster with far smaller hands than I have, in exchange for some pocket money. I also removed the two control sticks to give easier access to the front of the cockpit, where the rudder pedals are to be installed. It's an area that requires quite a lot of work.

I hope to install the antennas for the various avionics whilst I have the fuselage open. At the very least I will run the coaxial cables and make sure that all the necessary holes have been drilled.

Time spent yesterday and today: 3h 00m
Total time 22h 15m

Sunday, 5 April 2009

Inspector says YES!

Tom, my local LAA inspector completed the initial inspection this morning and has given me the go-ahead to start construction. He seemed very impressed by the Sportcruiser and happy to have one on his patch.

So it's all systems GO! Tom has given me some useful guidance on how to progress and when to call him in for inspections and as a result I am replanning some of my work. There is no requirement to do the work in any specific order, except in a few cases where there are interdependencies. It looks like I shall be starting on the fuselage tomorrow!

The picture shows Tom (on the right) and me alongside the Sportcruiser fuselage.

Friday, 3 April 2009

Inventory checking II

Whilst I'm waiting for the initial visit from the LAA inspector, I've been busying myself with checking out the kit in increasing detail. Eventually, today, I completed counting every component in each of the installation kits and as a result I now have a detailed catalogue of what I have and, equally importantly, what I should have but do not. I sent the list of missing items to the UK importer and we shall see what he has to say.

It's inevitable that a complex kit such as the Sportcruiser will have a few glitches but its evident that the same item crops up time and time again. A particular sized nut, for example is called for in many of the kits and is missing from most of them. I guess the factory ran short but in that case the kit would be known to be incomplete and should have been annotated as such rather than just leaving me to find out for myself.

The good news is that these shortages do seem to get resolved eventually, so I'm hoping that by catching the problem early on, I will have the missing parts before I actually need them!

I also took the opportunity to check out the engine, not that there's much I can do with it until I come to install it in a few months' time. It does look beautifully made and I'm really looking forward to that part of the project!

The inspector comes to visit on Sunday, so I'll be on my best behaviour and with a bit of luck he'll give the nod and construction can begin.

I spent 3 hours and 30 minutes at the workshop today, bringing the total time so far to 17h 35m.