The Wings Stayed On!: May Day Flight

Monday, May 19, 2008

May Day Flight

That's May day -- not "mayday!"

A short flight to do some sightseeing and record performance parameters for the little plane:

2 comments:

Aviatrix said...: Your OAT gauge made me laugh. I had the exact same model in my car. What's the green light right below the HI?; May 19, 2008 4:55:00 PM
Aluwings said...: //Your OAT gauge made me laugh.//

Yep... simple, cheap and also gives inside temp and Time. Such a deal!

//What's the green light right below the HI?//

Could it be the blue light indicating that my "standby" fuel pump is ON? As the engine has no magnetos or mechanical fuel pump, I was faced with some interesting design choices trying to maintain a similar level of reliability but keep it as simple as possible.

For (electronic) ignition reliability I created a "keep the engine running" bus immediately below the panel. It holds, from left to right, the ignition computer channel selector; CBs for the ignition coils; a switchable CB and annunciator light for the standby fuel pump; and two ignition power switches, each wired directly to one of the main batteries (through diodes to prevent back-feeding to the other battery). In case of electrical smoke or other problems I can switch off the Aircraft Masters without killing the engine. If that doesn't cure the problem, then I can switch off each ignition supply in turn... and if that dosen't cure it, I'm faced with switching off the engine etc...

The fuel is contained in two wing tanks. Because it's auto-gas it is doubly important to reduce chances of vapor lock by pushing the fuel rather than pulling it. So there is a "main" pump located as close as feasible to each tank outlet. Ideally I would have had the "standby" pump wired to run full time, but because it is in series with the main pump, this produces unacceptably high fuel pressure (the carburettor limit is 7 psi at the needle valve). So I have to manually switch the standby pump on for peace of mind when I want to balance wing tanks (i.e. switching a main pump off). A tad more complicated than I wanted. Ideally, I'd just have all pumps running all the time (as they do on cars for 100s of thousands of kilometers). I've thought of adding a pressure restrictor in the feed line to the carb, but that could fail shut (and do regularly from my online research) .... The standby pump is powered of course direct to battery, while the main pumps are powered through the essential bus. So again, I can unpower most of the aircraft with the Aircraft Master switch(s) and the engine will keep running.

I hope this answers your question?; May 19, 2008 5:18:00 PM

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What"s this about?

An eclectic series of articles based on my experiences as a commercial pilot. Sometimes behind-the-scenes tales; sometimes more technical descriptions of Jet Transport Aircraft - and the people who fly them. While the stories are based upon actual experiences and real people, I use composite characters and made-up names*. If they seem familiar, they are. They're the people you live and work with every day. The world is full of interesting people - if we only knew!

The title of this blog comes from my first observation after test-flying my home-built aircraft: "The wings stayed on!" And later I realized that life is often like that. We are continually faced with new adventures. And though we study and train and prepare as much as we can, finally we have to launch and put all this preparation to the test. And unexpected things still happen. As the bumper sticker says, Life Happens. And we deal with it - hopefully with a good dose of humour and hope. And if the "wings stayed on!" well at least that's the main thing. And everything else is just details.

My stories are usually drawn from looking back over my career, which thankfully has been pretty dull. Trust me. When flying a commercial airliner, boring is good. You wouldn't like exciting... So don't expect many stories about engines exploding, and wheels falling off, and cabins catching fire. Though that kind of stuff goes on, thankfully, it hasn't been my experience. My stories are the more mundane things, the little things that inhabit real life.

And while mundane is the reality of modern airline flying, still it's an amazing feat, a dramatic and dynamic accomplishment that we shouldn't take for granted. Perhaps day-in, day-out our world-wide airline industry represents our civilizations' most complex achievement. And though it has become mundane we should never forget that the real drama lies in the times when these bigger disasters are too close for comfort. The times when some small factors could produce seriously different outcomes.

Sometimes all the calm around you is an illusion -- a little like the movie Jurassic Park where the investors are touring the not-quite-ready-for-opening facility, while the technicians thrash away at command central, trying to keep everything together - trying to keep up the facade that it's all under control. But if it is, it's not by much.

Oh yeah, one more thing. Like everyone in the airline industry who's blogging, I'm hoping to write a book, and I'm practicing on you folks. I'm always trying to hone my story-telling skills so if you have any comments please leave them. Also, please respect the copyright thing.

Thanks.

Aluwings