August 31, 2008

Waiting, just waiting….

So here we are, the last day of August. Yesterday the weather here in the South of England was a scorcher – around 80 degrees Fahrenheit – but today is totally different. Sky is low, dull and completely overcast and we keep getting sprinklings of drizzle. Not much wind though, which is something I suppose. That dropped, at last, several days ago, not that there have been that many good ‘flying’ days since I was last airborne. But flying, in the AX3 at least wasn’t an option anyway.

The reason is that Rosie has had another, better, AX3 stored in her garage for some time. The time for G-MYRO’s annual check came round at the end of August so she decided rather than renew MYRO’s permit, she would swap the engine (and a few other bits and pieces) over from MYRO to the other AX3 and get that flying instead. She thought it would take a couple of weeks or so and that as the weather was not too good anway, to start the work at around mid-August.

Well, we all know what happens with the best-laid plans. The change-overs all went ahead as planned and the time came for the new AX3 to be inspected, weighed and permitted. Without going into detail, a complication has arisen to do with weight-and-balance and the calculated position of the aircraft’s Centre of Gravity. It looks as though one of the ‘standard moments’ used in the calculations is incorrect and until that has been resolved, the aircraft can’t be permitted.

Now we have to wait for the (slow) wheels of bureaucracy to turn and until they do, we just have to keep waiting. Anyway, hopefully I’ll be back flying this month – and as my last flight was on July 26th, it can’t come soon enough.

Just realised, after all the somewhat lengthy trials and tribulations involving The Gauge on Our Trike, I forgot to mention that I got the one that Dave kindly sold me working. It was quite a relief let me tell you! Since then, I’ve unfortunately been unable to get any more done. With time passing, I have to get the carburettor tuning sorted out. I found while running the engine to test The Gauge that even when warm, if you close the choke much beyond half-way, the engine stops. In a microlight, that’s not good ๐Ÿ˜• If that’s not sorted out it’ll never get its Permit even if everything else is sound. So that is now my next priority and hopefully I’ll see what I can do about it next weekend.

August 13, 2008

Blow It!

Both Manston and Lydd are looking at 45 knot gusts today – that’s something like 54 mph! The Silver Birches and other trees outside my window are being bent over and hurled around by the wind and the ground beneath them is littered with twigs and small branches that have healthy green leaves on them. We are becoming desperate for some high pressure to get these winds to drop but the forecast for the rest of the week is just as dismal. And the long range forecast for August is predicting more of the same.

I can’t in all my years remember a year like this. We thought last year was bad enough but this is even worse ๐Ÿ˜ฏ

On the upside (there is one?)….Dave’s gauge arrived this morning. At least I can look forward to fitting that this weekend ๐Ÿ˜•

August 12, 2008

Bit Of Luck!

The lows and highs of getting an old microlight flying again…

After the disappointment ofย  the weekend with The Gauge (see how it has now assumed an identity all of its own ๐Ÿ˜• ) I asked over on the BMAA forum whether anyone happened to have a spare one lying around. And Dave did have! So we’ve done the deal, the cheque’s in the post and soon it’ll be winging its way down courtesy of the Royal Mail.

What a bit of luck! Checked with the UK supplier and the news was that this is an old gauge which isn’t very popular any more (people want separate gauges nowadays). Apparently there is a model reference for it but the actual gauge isn’t even in their catalogue now. It could still be ordered though, but would probably have to be specially manufactured in the USA and the lead time would therefore be something like 7 to 8 weeks ๐Ÿ˜ฏ

But not as much luck with the weather though. The storms and high winds still keep roaring through almost without respite. This is more like Autumn weather – and bad Autumn weather at that. Last night we had a massive downpour in the early hours and although it’s now bright with a fair bit of white cumulus scudding across a blue sky, the winds are blowing a gale (well seems like a gale… ๐Ÿ™„ ).

The strip I’m flying out of is mid-way between Lydd and Manston in East Kent at an elevation of 410 feet, so it’s fairly susceptible to winds anyway and is also close enough to the English Channel to feel the effect of Sea Breezes. Its weather is more like Manston than Lydd and here’s today’s TAF for Manston.

EGMH 120903Z 121018 23022G37KT 9999 SCT018 PROB40 TEMPO 1418 4000 SHRA TSRA BKN014CB

TAF stands for Terminal Airport Forecast and it’s intended to inform pilots flying into or out of an airport what weather conditions they should expect. Here’s what it tells us.

The TAF was issued on 12th August at 9.03am local time. It’s valid between the hours of 10.00am and 6.00pm and the forecast is as follows. Wind from the south-west (230 deg) at 22 knots gusting 37 knots. Unlimited visability with scattered cloud at 1800 ft. For a while (TEMPO) between 2.00pm and 6.00pm (the end of the TAF, so it may go on longer) there’s a 40% probability to expect visibility to drop to 4000 metres in rain showers and heavier rain associated with thunder storms and broken storm cloud at 1400 ft. What a great weather forecast for August in the UK! Unflyable in an AX3 that’s for sure ๐Ÿ˜

Sighhhhhhh……. ๐Ÿ˜ฅ

August 10, 2008

Oh Dear…

Sadly, the saga of The Gauge drew to its inevitable conclusion this afternoon. One way or another it had to.

Connected up the new thermocouple sender unit but after starting the engine and letting it warm up for several minutes, there was absolutely no sign of a temperature reading on the gauge. Disappointing but not wholly unexpected, I suppose.

I’ll never know whether the gauge was fully functional or not when I got hold of it and it’s possible I was on a hiding to nothing right from the beginning. But in all honesty, close reading of the manufacturer’s web site did reveal that connecting the gauge incorrectly would probably lead to irreversible damage, which is probably what happened. Thermocouples only generate very small currents so it seems likely that if, during my ‘experimentations’, I inadvertently connected the RPM wires to the CHT gauge, the relatively much higher currents involved could have blown the internal circuitry.

So that’s it then. We’ll have to get hold of another one – I guess probably a new one this time. Another time consuming setback. Very frustrating indeed. ๐Ÿ™

August 3, 2008

Hooray!

Well, half of one really. It was important to do something about the problem gauge which has now wasted an awful lot of time and quite considerably delayed our getting Our Trike back into check. Just so people know what I’m talking about, this is what the gauge looks like.

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Cylinder Head Temperature is shown on the left hand scale and Engine RPM on the right. The gauge is a used replacement as the original had been damaged, and as the connections had also been messed up, I’d not been able to get it working after replacing the wiring as I didn’t know which wire was supposed to be connected where.

I had the idea a few weeks ago of asking for advice on the BMAA Forum and within a very short time was pointed towards the manufacturer’s web site where there is a diagram showing the connections for a similar model. This is what the connections on the back of the gauge look like.

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The gauge is in effect two gauges combined. The RPM connections I was advised, consist of a link to the magneto (which creates the engine spark) on one side and an earth on the other. The CHT connections go straight to a thermocouple (remember from school, two dissimilar metals that are in contact that create a small current when the junction is heated up). The thermocouple is held against the cylinder head by being screwed down under one of the spark plugs – pretty simple really but quite effective. It was easy to trace the thermocouple connections and according to the gauge manufacturer’s diagram, they should then be connected to the pair of connections on the back of the gauge numbered 3 and 4. Simple.

That just left connections 2 and 5 for the RPM gauge, with the ‘live’ on 2 and the earth on 5, according to the diagram. Marvellous! ๐Ÿ™‚

Dave on the BMAA forum had suggested that I checked things out with an electrical multimeter which was a good idea that hadn’t occurred to me even though I have an excellent Robin at home. So that’s what I did. Disaster!. It seemed to me that with the connections as they were, they were all ‘shorting’ out! The only way I could prevent it was by breaking the RPM ‘live’ connection, so back I went to the BMAA forum.

‘Yes’, said Dave, ‘It would appear that way but actually they’re not’. I had asked if anyone knew where I could get an ‘official’ wiring diagram for the Robin engine that showed exactly how the connections should be done and almost straight away, Ginge posted the following one.

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I’d said that the original connection had been made into a yellow wire which was in a group emerging from the magneto housing, and if you look carefully at the area ringed in red, you’ll see that that’s exactly how it should be. Dang! I’d broken that connection so now I’d have to remake it. ๐Ÿ˜

And that’s what I did this afternoon. And guess what – afterwards we had an Engine RPM readout!

But still no CHT reading. And then I remembered. When I bought the gauge, the seller also gave me a Rotax Water Temperature gauge (which Our Trike doesn’t need because it’s air cooled) and a rolled up length of what I’d thought was old wire. When I got it out and unrolled it, sure enough it was a thermocouple. So the question is, is our existing thermocouple not compatible with this gauge and will this ‘new’ one work? I don’t know – I didn’t have a plug spanner with me so I couldn’t swap them over. That will be a job for next weekend.

But at least with Engine RPM I’m half way there. So it’s half a Hooray! anyway ๐Ÿ˜‰