July 31, 2010

What else, for goodness sake

I am reeling at the end of today. The day’s sequence of events has left me feeling totally punch-drunk.

This morning I decided I’d refurbish the spare Mikuni fuel pump that I have with one of my recently purchased service kits so I could just swap it in for the upper one on MYRO. However, yesterday I had swapped over the main wheel tyre myself for a spare that I had and got a local tyre fitter to do the same for the nose wheel, so my first job was to refit those.

On arriving at the field the first thing I found was that the other main wheel was totally flat and had somehow managed to pick up a puncture while it had been just standing there. I just couldn’t believe it, after all this time. I refitted the other main wheel quite easily and then went on to fit the nose wheel, a job that took me a few minutes the last time I did it. But today, would the bolt holes line up? Would they heck. After about half an hour’s struggling and after chipping my new paint on a suspension damper several times, I eventually got the wheel into place.

Then it was onto the Mikunis. I swapped out the upper one quite quickly and then went on to see if I could do anything with the lower one without completely removing it. While undoing the securing screws I managed to mark the pilot’s side door plastic on a screw head which was a good start. And then when I went on to examine the unit, I immediately found the cause of all my fuel system problems. Firstly, I noticed that the unit had actually been only recently fitted from new when it had been on MYME and wasn’t an old, clapped out unit at all. However, an internal gasket had been wrongly fitted, probably in manufacture, and there was no internal seal between the two small internal one-way valves. So that’s why it wouldn’t pump and that’s why the system wouldn’t hold a pressure. Freak or what? What’s the chance of that happening? If you fit a new unit and it doesn’t work, you notice immediately and can take steps to fix it. But what earthly chance did I have of diagnosing a problem like that? I was going to refurb the unit anyway, but as it was all still ‘new’ inside, I decided just to reassemble it correctly and see what happened. So I did and of course, my fuel system then worked more or less perfectly.

Trouble is, that freak manufacturing mistake has cost me a two week delay.

So then it was onto the starter switch. I thought that I’d have to drop the panel front to get at it but I found that by removing the altimeter I could then remove the switch and detach the connections. While doing it, two of the tiny connection grub screws slipped through my fingers, fell into the pod and then out through the tiniest crack onto the grass below. Naturally, one I found but the other just disappeared off the face of the earth.

Colin said to be careful when I was taking the switch apart at home as you have to watch out for springs flying out. So I was, but two still managed to roll onto the conservatory floor. One I was able to pick up straight away but the other, like the grub screw, just vanished. So now my starter switch is useless, unless I can find the lost spring. I hunted high and low with a bright torch but there was no sign of it. If it means I have to take each piece of furniture out of the conservatory one by one and then search the floor with a fine-tooth comb tomorrow, then that’s what I’ll have to do.

But this day will go down as one of the worst I have had to endure for many a year. I had no idea that just trying to get the final few small jobs on MYRO done could possibly be beset by so many setbacks. And today they have been seemingly unending, one after another 🙁

July 28, 2010

Feeling a bit brighter

I found a supplier in the UK for the Mikuni repair kits at a third of the price being demanded by the UK Rotax agent, only £14.98 each compared to £45. I think the latter price is scandalous and a total rip-off. I will in future try to avoid buying anything off them if I possibly can. The link to the other supplier is shown below.

ZipNorth Mikuni Service Kit

The kits arrived a day after I ordered them and they look to be of very good quality. They also contain the parts needed to refurb the little internal one-way valves so I have high hopes that they will solve my fuel problems.

And this morning I received my package from America. On reading the paperwork that came with the starter switch service kit, I notice that it would have been quite simple to have opened the switch up and cleaned its internal contacts before fitting it. I think if I had done, I would have avoided my mag earthing problems, but hindsight is a wonderful thing and I’ll know for the future. I still think I’ll follow the service instructions and replace the switch’s internal contacts though, because that will make it good for another 2000 hours or so. Bearing in mind that MYRO has done about 1500 hours and the switch has been standing for almost two years, it’s no wonder really that it should need servicing, which the Bulletin advises should be every 2000 hours.

So as I’ve got my main and nose wheel in the car whose tyres need replacing, which I’ll get done shortly, I feel as though I’m getting back into some kind of shape again. The weather forecast looks good so with a fair wind, I should get all these jobs done by the week-end and hopefully then MYRO should be completely sorted. I hope that’s the case because I’ve been feeling a bit down this week with these and other problems I have right now, and I need something to perk me back up a bit 😐

July 24, 2010

Double disappointment

Well, John our postman came and went this morning but alas, there was no airmail letter from the USA. So it looks as though it’ll be another week before I can do anything with the starter switch. I’ll just have to live with it I suppose 😐

I went down to the field anyway just to see what would happen when I fitted the non-return valve in the fuel line. Well, initial indications looked positive – when I primed the system with the electric pump and then switched it off, the system retained the pressure. However, as soon as I started the engine, the pressure fell away rapidly just as before. So there’s only one conclusion – either or both of the Mikunis that I got off MYME are faulty and are not making any, or at least not enough, pressure. This is really disappointing as the repair kits for these items are a total rip-off at £50 for a few gaskets that cost a few pence to make (I used to work for a company that manufactured gasket materials and gaskets so I know). This is so typically Rotax 😡

I ran the engine for a bit and even tried getting up to full take off revs, but still no pressure.

There is one small thing that encouraged me though. MZEL ticks over at 3000 RPM with the 2-blade wooden prop and would stand there all day without moving. At the same revs, MYRO, with the 3-blade Arplast, starts to roll and has to be held on the brakes, so it looks as though the Arplast will give considerably better performance than the original wooden prop. Wonder when I’ll get to fly and be able to try it out 😕

July 23, 2010

Getting set for tomorrow

I’ve had a couple of discussion threads going on the BMAA forum about my fuel pressure problem and also how I should go about changing the tyres on my nose wheel and one of my mains for two spares Rosie gave me when I bought MYRO. She had swapped the wheels and tyres that were on MYRO with those on MZEL and the two I just mentioned are too perished to get through Permit Inspection. However, the replacements she gave me are fine and just need to be swapped over. I would prefer to let a tyre fitting establishment do it but I’ve heard of cases where rims have been damaged because they are much smaller and more fragile than the ones tyre fitters are accustomed to working with. I’m still thinking about it and will decide later, probably after I’ve had a go at doing it manually.

One of the contributors to the fuel pressure thread said that when an electric fuel pump is fitted, the lower Mikuni should be removed and even without the hand primer bulb being fitted, the remaining Mikuni and the fuel pump should be effective together in retaining the system pressure. MZEL still has its lower Mikuni because it has MYRO’s original fuel system fitted, and so also did MYME as MYRO now has its system. I therefore do not see how this can have been the ‘usual’ thing to do if both MYRO and MYME had passed Permit Inspections. I do not want to remove the lower Mikuni which is now in MYRO, mainly because I don’t want to have a ruddy great hole in MYRO’s pod! I’m also concerned that the only Mikuni repair kits I’ve seen being offered by the UK’s official Rotax agent only include gaskets and internal membranes and do not include any parts relating to internal non-return valve repair. I do accept that the Facet electric pump may be worn even though it’s producing enough pressure to prime the system but I’m loathe to chuck it away while it’s doing it’s job ie priming the system before being switched off.

The hand primer bulb incorporates a non-return valve and one option I have is to replace that in the fuel line. That will still allow fuel to flow up to the carbs but should stop it flowing back. But I have to be honest about one thing – I turned out one of the pics that I took when I first got the parts from Mark at Galaxy when the fuel system was more or less complete and that shows the primer in parallel to the electric pump and by-passing it. Such an arrangement would result in any non-return function it had having no effect so if MYME’s system was working properly, it would have needed either or both of the Mikunis or the Facet pump or all three to be functioning as non-return valves. This does rather indicate that the Facet pump at least is worn and should probably be replaced. I’ve found a source (on the Internet of course 😉 ) and the cost is not that high, but I need to get the part number off the existing unit this week-end. In the meantime I have sourced a small non-return valve intended for fuel pipelines that I’ll fit tomorrow just to see if it does work, thereby confirming my diagnosis. It wasn’t expensive (about £4.75 on Ebay) and I prefer that to fitting the primer bulb, many of which have proven somewhat unreliable and liable to block and cause more trouble than they’re worth, the reason why I took MYRO’s out in the first place.

Now onto the starter switch. I checked and found that a replacement two-mag starter switch comes out at about £145 and an Internet search seemed to indicate that there is a Service Bulletin out on the actual switch fitted in MYRO regarding replacement/repair. The latter idea caught my attention and as part of my search, I found a repair kit for the internal switch contacts, which I am sure have failed in MYRO’s switch, on sale in the US for the princely sum of $16.75. A bit different from £145, eh 😡 So I ordered one earlier in the week, together with an outer bezel plate costing a mere $1.75 that will make MYRO’s switch look almost ‘as new’ again. What would we do without the Internet – how did we use to manage 🙂

I’m now just waiting for the small package to be delivered. The supplier kindly advised me that the delivery method I’d asked for was going to cost about twice as much as the items so they switched it to Air Mail. It hasn’t arrived yet and it would be very nice if it dropped onto the doormat tomorrow. If it doesn’t, that’ll be yet another week I’ll be delayed as I can’t see me being able to do the job until next week-end if I can’t do it this 🙄

So there we are – I shall at least try fitting the non-return valve tomorrow and maybe I’ll be able to make a start on the tyres. I’d like it very much if I could do the starter switch as well, though 😉

July 18, 2010

Small steps forward

Today my plan was to swap the upper Mikuni fuel pump for the other one I have, to see if that solved the fuel pressure problem and then to see if I could track down why my magneto earthing is not working. I realised when I got the Mikuni out of the garage that this was the one that was previously fitted to MYME, so I reasoned that there was a good chance that fitting it would solve the problem.

In fact, when I drove onto the field, I found that John and Bob were already there and that they’d dug out a Warp Drive prop pitch tool to see if it would be any good for adjusting my Arplast. This was too good a chance to miss so I decided to check the prop first.

The Warp Drive tool ideally needs two parallel faces to work accurately (front and back faces of the prop) and where you need to fit it on the Arplast is far from that shape (more of an aerofoil shape actually). So there was a bit of guesstimation involved in getting the tool in exactly the same position on each blade to check the pitch angles of each. Even so, it indicated that one blade was 1 degree out (over pitched) compared to the other two, so I changed it to make them all the same.

Then I swapped over the Mikunis and checked the connection of the earth lead that goes down to the starter switch and couldn’t find anything wrong with it, really. So then it was time to start the engine again to see how it ran.

DRAT AND DOUBLE DRAT! I’d forgotten to bring my ignition key, which was still at home in my conservatory 🙁 Only one thing for it – drive home and get it. So that’s what I did. It took an hour and a quarter what with all the Sunday drivers and when I got back, John had gone and only Bob was still there. We had a brief chat and then he also left, leaving me to see what effect the changes I had made would have.

The prop change seems to have worked a treat. Now the engine seems much smoother and I’m amazed how much difference one degree on one blade has made. I did one aborted take off run and I’m pretty certain revs at full throttle were also much closer to where they should be. So that’s that job sorted for the moment, but Kev on the BMAA forum is sending me his Arplast tool to borrow tomorrow, so I’ll check things out yet again properly next week-end.

The Mikuni change, though, made no difference and I now think I know why. MYME (which this system came off) used to have a hand primer bulb in the fuel line and was obviously being operated like that. I removed the bulb because there seemed little reason for it, what with having the electric pump and also because there have been reports of primer bulbs blocking and causing fuel starvation. But the thing is, the primer bulb has a non-return valve in it. I understand that the Mikunis do not contain proper non-return valves and it’s doubtful I think, that a worn fuel pump would effectively stop fuel from flowing in reverse when switched off and under pressure. So that leaves the primer non-return valve as the only effective barrier to prevent this, and I’ve removed it. Makes sense, doesn’t it? Anyway, it’s going back in again next week-end to see if that solves the problem – better that than to lay out £50 each for two Mikuni repair kits only to find that when fitted I still have the fuel pressure problem 😕

Now what about the mag earthing? Well, I’m still uncertain about this. Earlier I’d moved the starter switch earth connection through which the mags are earthed to a different position but the engine was still not switching off. Then it occurred to me, and I confirmed it by digging out my original diagrams and cable colour codes from when I did my MYRO’s wiring all those months ago, that the RPM gauge shares the same earth connection on the back of the starter switch, and that of course is working. This says that the earthing must be good in that case, leaving only the final possibility that the problem must therefore be inside the starter switch. This did not come as a great surprise actually, a I know that when I wired up the switch and indeed the whole of the panel, I took very great care and checked that everything worked as it should. The only mystery now is why has the switch failed after doing that? Anyway, I now need to get hold of a replacement twin-mag rotary starter switch. They can be a bit pricey, though, but there’s nothing else for it.

I’m working my way slowly through the problems but it’s a rather tedious process that’s taking me longer than I might have thought. However, each little step is taking me closer to finally getting MYRO into the air. I just hope that when I finally do, we still have some good weather 🙂

July 17, 2010

Not such a disaster after all

I bought some new plugs on Ebay earlier in the week, a box of 10 so I’ve got a spare set just in case. I carefully gapped them before leaving for the field and when I fitted them I realised that the leads from each mag are already crossed and are in pairs ready to go straight onto the plugs. Stupidly I didn’t notice that previously and had crossed them again, so I had both leads from each mag on the same cylinders. No wonder it ran rough last time 😯

This time the engine started immediately with plenty of power and ran perfectly. Great 😀

Also all the temp gauges that I’d carefully wired up and checked are in fact working just as they should. I was too impatient last time and they just needed time to come up 😉

But there was still no fuel pressure indicated when the engine was running, although the two Mikuni fuel pumps are producing enough to keep the engine running indefinitely. When you switch the electric fuel pump on with the engine stopped, pressure comes up but falls away again when the pump is switched off, so pressure is being lost somewhere. I haven’t noticed any leaks so I think that one or other of the Mikunis has an internal leak. I even detached and bled the tube running to the pressure gauge by switching on the pump and allowing fuel to run into a container so I don’t think it’s air in the system, which I suspected might be the cause. As a last resort I may have to buy a couple of repair kits for the two Mikunis – not cheap though at nearly £50 each!

But the mags are still not earthing so I will need to find out why that is. As a result I’m still having to shut the engine down by pulling the choke which I don’t like, although I know some two-stroke owners actually prefer to do that all the time because it draws oil into the cylinders when you shut down.

I also did some taxying today. I don’t think my pitch gauge was accurate enough because it isn’t as smooth as I expected, especially when you close the throttle. Having said that with nobody flying because of the wind, I was able to do a couple of aborted take offs. MYRO accelerated beautifully although I think the revs were not quite up to what I want to see at full throttle, so the pitch must be a bit coarse. But the prop seems to whip when you shut the throttle quickly. I don’t know if that’s a feature of the Arplast but I haven’t noticed it before when flying with the wooden GSC two-blade prop, so I’ll have to look into that. I will definitely need to borrow a prop pitch tool, I think.

So my jobs tomorrow are – try the spare Mikuni I have to see if it solves the fuel pressure problem and try to find out why my mag earth connection isn’t connecting. All in all, not as bad as I originally thought, I’m glad to say. I might be flying a bit sooner than I reckoned after last week end 🙂

July 11, 2010

Back down to earth with a bump

After the successes of yesterday, I allowed myself to be carried away by a sort of euphoria that had me convinced that taking to the air in MYRO was just around the corner and today I allowed that to cloud my judgement. I put 200ml of two-stroke oil in a jerry can and on the way to the field, I added 10 litres of unleaded with the idea that when I arrived, I’d try starting and running the engine for the first time.

I shouldn’t have done it because I hadn’t even bothered to check whether the spark plugs that were fitted were the correct ones let alone that they were clean and gapped correctly. All I know is that they were in there when I acquired the engine and I got Bob to torque them in without further ado. Then I gave the engine a few hand turns.

I added the fuel to the tank and was rather disappointed to see how slowly it transferred from the main to the second tank. Mike who sold me the tank said they found it slow when they had it but I have to say that it was slower than I expected. Then I climbed in, turned on the master and switched on the fuel pump. It rattled away but failed to produce any fuel. I was going to call it a day but Bob suggested turning the engine a few times on the starter to see if that might help. So I did and then tried the fuel pump again. This time it did its job – clever Bob. However, I expected to see the pressure comfortably exceed 0.2 bar but it only just made it. Anyway, I set the choke and gave the starter a whirl. After a few turns the engine fired and started but never ran anything like it should have. It was far from smooth and there was no fuel pressure unless I kept the pump on. Not right at all. I managed to get the engine running fairly smoothly at about 3000rpm but I couldn’t get the revs to rise any higher and I still had the fuel problem. I kept it running to see what would happen with the temperatures and then had a major disappointment. Bearing in mind that I’d carefully re-wired MYRO using MYME’s wiring loom and double checked everything along the way, I was really disappointed to see that only one of the two exhaust gas temperature readouts seemed to be working and neither of the cylinder head temperature readouts. What on earth can have happened to cause that. But even worse was to come. When I shut the throttle and switched off the mags, the engine kept running. This was terrible news. Strangely, Chris my GST examiner had asked me how I would shut down an engine that would not stop on the mags and now here I was barely a few days later having to do exactly what he suggested – apply the choke. It worked, but the problem suggests to me that there is something seriously wrong with the magneto earthing, on one cylinder at least anyway.

This is not a good development at all. I’ve already ordered up some new spark plugs but checking the wiring out is not going to be an easy job now that the panel and wiring loom are in place. But I’ll just have to do it.

After this what can only be described as a debacle, unhooking, untangling and reattaching the rudder cables was a doddle and it was good to see MYRO’s ailerons sitting exactly even and feeling just the way I remembered them. But these engine problems are now going to put me back yet again, probably by another two weeks at least. I wonder when I’m ever going to be able to start flying MYRO at this rate.

And before leaving for home I’d wanted to cover MYRO with my new tarpaulin that I’ve had for quite a few days as we’re expecting some rain in the middle of the week. No chance. Because of the wind, if I’d tried to do it alone, it and I too probably would have ended up in the next field, so I wasn’t able to do that either.

I was not in the best of moods when I left for home. Big problems at Linton are becoming a bit too much of a regular occurrence 😡

To finish off, a few more pics that I took today that put me in a slightly better mood – just 😯

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July 11, 2010

Dratted birds

A few off-topic musings that came to me while I was walking the dog this morning and which I posted about on a forum of which I’m a member.

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The roadsides and other green areas of the estate where I live are peppered with cherry trees. I guess when the original planners conceived of the idea they had visions of the glorious display of blossom in the Springtime and they were, of course, quite right. The magnificent spread of white and pink is indeed a joy to behold and especially uplifting to the spirit after a long and dismal Winter such as we had to endure this year.

But there’s one factor that the planners either overlooked or ignored. This year the conditions have been almost perfect, with a damp Spring followed by a glorious hot period that has resulted in a bumper cherry crop. They are almost all of small varieties that you wouldn’t like at twice if they were on sale in a shop but nevertheless this year they are delicious. And nobody ever bothers picking any.

Except for the birds that is. They love them. Even if any human did bother picking any from the lower branches they would still be left with the majority of fruit that is out of reach at the higher levels. And they take good advantage of that. They take great pleasure in devouring this at high speed and beginning their unique process that converts the fruit into a product that varies in colour from deep purple to garish red. This they then promptly deposit over the waiting cars that have been parked by loving owners below them, in waiting for the moment.

They make no distinction – the most expensive Mercedes is treated in exactly the same way as the most rusty old banger, sometimes the Mercedes might even receive two or three pot shots while the old banger might go completely unscathed. But woe betide the owner who, if their beloved motor is on the receiving end, ignores the fact because this stuff is like battery acid and will eat through your paintwork in a trice. How the birds’ backsides stand it I’ll never know. Luckily, I don’t have an expensive Mercedes, only an old Honda Accord, so I don’t have to worry to much when the birds wreak their vengeance on it 😉

July 10, 2010

A successful day

The scorching hot weather that we’ve been enjoying in the south for the past couple of weeks or so looks set to continue for quite a few more days yet and although we’ve been told to expect some light showers on Wednesday, the temperature is still expected to stay pretty high. I bumped into a lady while walking the dog this morning and she said although it’s hot here, she’s just returned from Germany where they have temperatures of 38 and 39 deg C and without the breeze that we have that helps make it more comfortable.

Today was the day for the proper test of my patent prop pitch gauge and first of all I had to move the garden table to find a bit of shade where I could do the work. Here’s a shot showing everything laid out ready to start.

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I’d had to take a bit of a ribbing about my gauge from my mate Terry Viner on the BMAA Forum but I didn’t mind that in the least. The proof of the pudding and all that 😉 Here’s another shot that I took of the gauge in use.

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Actually I’d finished by then and I’m delighted to say that it seemed to work an absolute treat 😀 I was amazed how easy it was to set the prop up and how quickly I was able to do it. I’d finished within 10 or 15 minutes which I found incredible. And from what I could see, the pitch on each blade looked to be very consistent, although I won’t know for sure until the engine is run and I see what revs I get on full throttle and whether there’s any vibration.

My next job this morning was priming my new battery that was delivered a couple of days ago. It’s a small Varta motorbike battery and was recommended to me months ago when I asked for advice on the BMAA Forum. I got it from Tayna Batteries and it only cost around £25 so it wasn’t worth taking up the offers I’ve had from time to time of second-hand ones. The battery is a sealed unit but the acid comes separately. I wondered for a while how to get it into the battery itself (I’m sure there were instructions but they weren’t immediately obvious) and then I realised that you invert the acid containers (all six of them, one for each cell, which are joined together) over the battery cell openings then press down so the containers are pierced allowing the acid to flow into the battery. Then when done, you press the rubber seal into place and that totally seals up the battery. Ingenious.

Then I was off to the field. Bob and Paul were there sitting in the shade with, would you believe, two electric fans running powered by a small generator 😀 I left them to their brews as I couldn’t wait to get MYRO’s prop on. The guys came down to lend a hand a bit later and Bob loaned me his torque wrench which is smaller than mine and possibly more accurate, to run the main prop retaining bolts up. I have a feeling I’ve over-torqued the prop blade pinch bolts which only need to be at 6 ft-lb but I’ll leave them now they’re done. I think my torque wrench may need a bit of ‘exercise’ as it hasn’t been used for such a long time. It’s well-known that torque wrenches need to be regularly used for them to retain their accuracy and that’s the problem with mine I think. It’s not permanent, it just needs to be operated a bit. Then I fitted the battery and connected it up. I knew it would work because I’d tested the basic electrical system at home when I’d finished it but I still couldn’t resist seeing the warning lamp light up when I turned the master switch on and hearing the fuel pump click into action when I operated the switch 😉

All I then had to do was refit the wing join top and bottom covers and MYRO was finally finished. I said to Bob later when I left to drive home, it’s the first time that I’ve left for home and left a fully complete aircraft behind! Here are the first shots I took of a now complete MYRO.

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It was a great feeling to see how far I’ve come with MYRO and to know that now the end of the project is so close. But not quite! I found that somehow I hadn’t noticed that when I uncoiled all the cables that had been wound together in MYRO’s fuselage, one aileron cable was still wound across the rudder cables. So that’s my job for tomorrow. It won’t take long, just to disconnect the rudder cables, untangle the aileron cable and reconnect them. Bob was saying today that he couldn’t understand how I could fit the prop today and not want to start up the engine! Well, I was going to keep the fuel tanks empty until MYRO had been weighed as part of its permit inspection but maybe I will take a few litres down with me tomorrow and give in to the temptation 😆

July 9, 2010

A triumph of function over form

I’ve been trying to borrow a prop pitch gauge for ages now but although I thought I had one lined up, it hasn’t materialised. Ginge over at Saxon Microlights has one but we don’t know if it will work with my prop. The same goes for Bob. His is for a pusher arrangement anyway so it may not work with my tractor prop, although I don’t know for sure if there’s a difference.

But anyway, I really want to put the prop on tomorrow as I’ve now bought a new battery and with the prop fitted, MYRO would be more or less ready for inspection. I was searching the Internet over lunch for topics to do with pitch gauges and came across a very interesting article on how to make your own. It was actually for model aircraft builders, but as they said in The Flight of The Phoenix, the principles are just the same. The article described a design that was relatively quite elaborate with an adjustable protractor so it could be used to adjust pitches over quite a range but I realised that what I need is something far simpler, just the ability to set my prop blades to one specific angle. It got me thinking.

My prop is a 3-blade Arplast of 165cm diameter. The ‘rules’ in the form of what is called a ‘MAAN’ to which I must strictly adhere in order for my set up to be approved, are quite specific. I must set my blades to a pitch of 14 degrees at a radius of 53.5cm. The more I thought about it the more I realised that using a similar method to the one I read about at lunch time, this is actually a lot easier than it sounds.

All I needed was a flat board about 70cm long with a raised block that the prop hub could be mounted on at one end with all three prop blades in place and a line drawn across the board at the 53.5cm position at which a 14 degree wedge could be positioned. Then for the first blade, with the pinch bolts loose enough so the prop blade could be rotated in the hub, all that I would need to do would be to position the wedge on the line and rotate the blades until they sat tightly on the sloping face of the wedge and then tighten the blade pinch bolts. With the process repeated for the other two blades, that would be ‘job done’. Piece of cake 😀

It isn’t often that you can conceive of a plan such as this, find the odd materials that you will need in your garage, set to with saw, drill, screwdriver etc and end up with a finished article that works as planned. But that’s what I did this evening and it only took an hour or two! The most accurate part was making the 14 degree wedge. For that I used an engineering adjustable protractor that used to be my father’s and I’ve had since I was small boy, to mark a line at the correct angle on a suitable piece of timber and then I carefully cut down the line using a hand saw. I completed the job by planing the sloping face to make it nice and smooth.

Initial tests indicate that it works like a charm – but that’s not surprising because it’s so simple, what can go wrong? It was getting dark by the time I finished but here’s a pic showing the gauge in all its glory with a blade and the wedge in place showing how the 14 degree setting is achieved.

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It may not be very elegant but who cares if it does the job. I think it will – but I’ll find out for sure tomorrow 😉

July 4, 2010

On the home straight

I had a couple of little bits of luck today. The first boat chandler I phoned this morning at Wateringbury said they’d be open all day and that she had a selection of stainless steel shackles in stock. So after I’d got myself sorted out, I dropped into Portguide Marine at Bow Bridge on my way through. What a very nice lady she turned out to be. When I saw the shackles that she had available, they were all a bit too big and chunky for what I wanted and intended more for larger river boats than small sailing dinghies, which is the kind I was looking for. I happened to mention that although I was going to buy two matching shackles in fact I only needed one and that was only because the clevis pin and safety ring had been lost from the one I already had.

She then nipped smartly round to the rotary display rack that I hadn’t taken much notice of up to then and started pulling blister packs of replacement clevis pins off it to compare them to the one I was holding. She even ripped a pack open to take a closer look. It turned out that there was a pack of two clevis pins on there of exactly the same size as mine – £1.70 + VAT complete with rings. I apologised that I couldn’t spend more with her as she counted out my change and then off I went. What a bit of luck and what a Happy Bunny I was 🙂

I didn’t bother untying MYRO and pulling it out because with the nose and tail tie-downs left on I could clamber around inside without fear of it tilting and over-balancing in either direction. I’d already attached the external aileron cable connections and all that was needed was for me to attach the two inner ones. I did the first one without too many problems and Bob arrived while I was getting ready to do the second. That was another bit of luck because I knew that the last connector would be the biggest problem because of the tension in the aileron cables.

I propped both ailerons up to minimise the tension in the cable run as far as possible and struggled for a bit to connect the last shackle, but without success. So I then decided to stop for a cup of tea and a chat. Afterwards Bob said that he’d come down to give me a hand to do the last connector but before he did, I realised that if I disconnected one of the external aileron connections it would then be easier to connect the one I was having problems with inside the aircraft, because the aileron cables would then be totally slack. That would also mean the last fiddly one would be on the outside where I could easily get at it. It worked like a charm, so it shows that it pays to use your brains before starting the job rather than after.

When Bob came down, I removed the prop from under the aileron on the side that I’d disconnected and asked him to gently lift it. He did and I had the last shackle fitted in a couple of seconds. In many ways this was a bit of an anti-climax because with that shackle on, bar the prop, it meant that MYRO was at last fully back in one piece for the first time since August 2008. It was great to move the stick from side to side and see the ailerons moving up and down as they should – quite an occasion to celebrate 😀

All I could do then was tidy up but I had to take a few pics, of course, to mark the occasion. If you compare the next shot, below, with the last shot from the previous post, you’ll notice that for the first time since the wings went back on, the ailerons now don’t both droop downwards but instead line up as they should.

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The next two shots show that MYRO is at last beginning to look like a complete, flyable aircraft, just the way it should.

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The next pic is the first shot I’ve taken of the new panel since the wings went back on. All of the panel shots taken up to now with the wings off have given a totally wrong impression because of the amount of light entering the cabin. With the shadow produced by the wings this shot shows much more what it will be like flying MYRO with its new panel.

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We’ve had a strong, gusting south-westerly wind today (the last thing you need really, when working on ailerons…) so before I secured MYRO’s doors to go home I took a strong bungie cord and used it to lock the control stick so it was held down and was also unable to move from side to side. That way the wind will not be able to damage any of the control surfaces by banging them up and down. The final shot I took from the rear shows the ailerons now nicely lining up with each other.

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So what’s left to do? Not a lot now. The remaining biggest and most important job is fitting the prop and aligning the blade pitch, but with the right tool that should not take too long. Then all I have to do is tidy up the little digs and nicks in the fabric, do the paperwork for the Mods that now apply and make the placards that must be on display in the cabin. Then MYRO will be ready for inspection and permitting. Yes, I really am on the home straight now, with the finishing line almost (but not quite) in sight. 😉

July 3, 2010

Nice surprise for a change

I phoned Bob late morning to see if he knew whether anyone planned to be at the field today. The reason was that to get MYRO’s wing back on I now know it can be done in just a few minutes if you have a couple of helpers. He said that Robert might be along later in the day but otherwise as far as he knew there would be no one else there. I felt like going anyway just to feel some fresh air on my face so after I’d finished a couple of things I had to get done, I set off.

When I got there I found that Bob and Tony had flown off earlier and were still away so I went down to make sure that the tarps covering MYRO hadn’t moved and the tie-downs were still taught. Everything was fine and while I was pottering about, Robert turned up. Apparently he’s got an altimeter problem on his Easy Raider. Poor Robert’s had a bit of a bad time of it over the last couple of months. First he had an engine problem that after a lot of messing around he diagnosed as problem with a split or perished rubber tube and now it’s his altimeter. I hope he manages to sort it out – if he can’t he’s thinking about fitting a digital readout gauge which will be interesting.

Then John arrived. He came down for a chat too (I’ve said before many times, it’s one of the best bits about flying microlights). I said that I was now planning to get MYRO’s wing on tomorrow and they both said, why wait! Now that was an offer I could not refuse, so while they chatted together, I pulled MYRO out and got everything ready.

Sure enough, within a few minutes, now I know how to do it, the wing was back on. The next shot was taken after the wing and all the struts had been fitted and the one after, after I’d fitted and connected the pitot (the open-ended small tube fitted to the front strut on the left wing) in which air pressure is created when in flight that produces the airspeed readout.

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When both wings are attached, there is a gap between them. There are a number of webbing straps that span across the gap top and bottom and when they are pulled taught they apply tension and pull the fabric tight on both wings. Then top and bottom fabric covers are fitted attached by Velcro. The next two pics show MYRO with the covers off while I was still working and then with the covers on when I’d done everything I could for today.

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Here are a few more pics that I took in the early evening before I cleared up and went home. The covers make MYRO weather-proof and as we are not expecting any rain tonight anyway, I didn’t bother to put the tarpaulins back over MYRO today.

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I connected up the aileron control cables on the outside quite easily but I decided it was time to wrap things up for the day when I went to connect the aileron cable that’s inside the aircraft. The reason was that it’s connected by a shackle at each end and one of the shackle pins and its safety ring had been lost. I need to check, but there are some boat chandlers at Wateringbury and Teston Lock who I’m sure will be open tomorrow on my way in to Linton. If so, I’ll just need to buy a couple of new stainless shackles of the right size, and Bob’s your Uncle 😉

When I’d tied MYRO down I was so pleased to see it looking like a complete aircraft at last and took this last pic for the day.

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If I can get the shackles I need tomorrow, I’ll actually be able to get MYRO all finished bar fitting the prop and I can’t do that yet because it needs a prop pitch adjustment tool. But it was a very nice surprise to get done what I did manage today because I’d mentally resigned myself that tomorrow would be the day for getting the wing back on. How nice it was to actually see it on this evening when I left for home 😀