Posts by Dave Berenholtz

Do we have a problem?

Yes the cowl is vibrating a little too much for my liking. It isn’t touching the ‘lampshade’ around the prop extension yet but it is certainly close. This is another thing I had put off to see if it was an issue or not. It is.

I had a pretty good idea how to fix this using a technique that goes all the way back to the Education Chapter 3 in the plans where you make a ‘confidence’ piece. I also looked to my good friend and build buddy in the US, Wade Parton, who did a sterling job in roughly the same place addressing the same problem. Of course no two builds are the same and mine came out a little wider and higher as I may have had a touch more room.

The first issue is how little room there is to put a stiffener in place and have a healthy gap to the bottom of the top cowl. It turned out to be even less than this blue block in total.

It took a couple of hours of sanding to get down to the carbon as that skilfully applied undercoat and two pack top coat really wanted to hang on.

I eventually got there without loosing much thickness at all. That’s why it took a while.

I made a less than elegant dam with scrap cardboard and duct tape.

Even uglier is the pour foam. This stuff is great. Nice and light, you just have to contain it. I do something like this in several layers or you know its going to go everywhere.

I like to progress evenly and then keep putting the cowl on to check the height.

With the cowls done up and the clearance height confirmed, I went ahead and rounded the foam to make it ‘nice’.

Then I went ahead with a sort of pseudo hard shelling procedure. I knew putting micro on to transition the edges and then the carbon, it could get out of control. Here I have spent a while getting the micro smoother than it looks in the pic. I wanted it to be sticky but not fully cured for when the cloth went on.

I’m going for three plies of BID at 45 degrees. Each piece is 4.2″ wide and 33″ long. The easiest way to do this is wet out the carbon in one piece, then cover it with another piece of plastic and squeegee all the air out. Then its a simple matter of cutting out the three long strips so you end up with exactly sized wetted out carbon with plastic both sides really for the layup.

With all that prep work done, getting the carbon on is a piece of cake. I did peel ply just at the edges for a smooth transition. This often takes as long as putting the wet cloth down.

It looks like I have enough clearance in the middle. It is certainly too hard to photograph without breaking out the endoscope. Being cured enough and still at the ‘plastic’ stage I put the cowls on and let it go really hard in the correct position. This way the bend in the cowl should match where its going rather than fighting me every time I put it on.

While the carbon looks great, I’m going to clean it up after the cure and hit it with some high temp paint to finish off.

Despite all this masking care I did, there was some clean-up needed after a little ‘blue bleeding’. Paint doesn’t care how much time you put in. It shows no mercy, you have to get things absolutely perfect.

Why blue? Well it matches the registration marks on the sides. You can’t see it when the cowl is on AND it was easier than going to a spray booth and trying to match the white. Yes, I should have done this before paint. Here’s turning a mistake into a feature. Oh, and someone else suggested the colour too, so I can’t even take credit for the idea.

Post ‘adding the stiffener’ test. I’m really pushing on this and it is nice and solid compared to before. I don’t think it will be a problem with the engine running now. A bonus is that the top cowl is a bit easier to put on as it is more stable across the back. I’m calling this one done.

I’ve know it for a while. Those exhaust pipes are too close to the top cowl.

Is there any doubt?

I put this off as I really didn’t have a welding person who could just come and do it.

Now its really time to do taxi tests with the cowls on and as my luck would have it…. Hold on, Murphy has been co-building this plane from the start so where is a welding person? Despite this trend, my delaying worked and a very skilled welder has appeared.

Even better, a mobile setup so we would work ‘in situ’. I can’t show you his face, he is of course, very busy.

I’m not going to tell you how many times the exhausts came off and went back on. We needed two sessions in the end. He made a cut and we would assess. Then another cut and again rechecking. Finally a tack or two. Cowls off and on many times. The idea was to loose the minimum amount of material and just ease into the right position. I also discovered that you need the exhaust nuts done up tightly as almost tight makes a few degrees of height change.

Given I had the pipes ceramic coated inside and out, that had to be removed for the welding, but only in a small area. Yes you can buy 2000F paint, do you think I can get it is satin black? Matt black had to do. I didn’t want to wait a week or two.

With the masking tape making clean lines its not too horrible and you can’t see it with the cowls on anyway.

This is where we ended up.

Well clear of the top and bottom cowl.

I really did want the pipes a bit closer to the prop and pointing in but realistically that would have made them quite a bit shorter. This may or may not have been a problem as no one seems to know the ideal distance from prop to exhaust. I don’t have the time for extensive testing and multiple exhaust pipes of various lengths and angles to find out the truth. I suspect what I have will work OK if not the absolute optimum. I’m not racing, my mission is of another flavour.

The problem was still waiting to be found….

I added a pointer for TDC and we confirmed all the spark plugs were firing and in the right order and the right place.

We confirmed yet again, the magnets that trigger the ignition were all correct. That’s the T1 S1 T2 S2 which light up when the flywheel magnets is in position over the pickup. All good.

Why was it running so rich that we keep getting backfires? I pulled the air intact apart to look for a rag I must have left in there.

No rag, clean as a whistle.

I rechecked the throttle position with what was happening down the back with that butterfly. Confirmed, I was getting throttle fully closed and open in sync with the throttle position.

Of course we had gone back to the wiring as well and with diagrams of pinouts at the big multi connectors we again checked everything and buzzed out the wiring. All was correct and connected as it should be.

I gave the new flywheel a lick of paint. The new bolts finally showed up from Texas along with the new insert. They were held up in quarantine by the wildlife people.  Who knew steel was a carrier of things dangerous to the native flora and fauna? I guess they needed to charge some storage fees.

The insert went in the freezer overnight and the licensed engine guy in the hangar made short work of installing it. I don’t think I’d have done so well. Everything is on a steep learning curve for me and there are times when its better not to have a couple of goes.

The bolts and the inserts were again very carefully cleaned. I chased the threads with a tap and die. This will be my new SOP (standard operating procedure) The prop went back on with anti-seize, yes my call,  and I had another go at trying to improve my lockwiring.

Through some friends we had made contact with a race car guy who was very experienced in ignition and fuel systems. Next came another wait for his availability.

THE RESOLUTION!!

Gary, (Mr Fuel and Timing) hadn’t done this sort of thing on airplanes and it took a bit to get him comfortable and explain we were only wanting him as a ‘consultant’ rather than walking away and expecting everything fixed. He knowns what a piston engine should be doing in terms of spark, fuel and air.

I had a print out of the Fuel Map and he gave it a good read. You can’t access all the numbers directly at the plane. You need to download the file and put it on a PC to view and then edit. The file is then uploaded back into the EFII system in the plane.  Here are the first few numbers of the original file.

He didn’t like what he saw. He felt that the settings for starting were overly rich and this was the problem. I am still not 100% on what I am seeing here. The big numbers at the higher MAP end really got his attention.

So rich for starting. Ok here are some of the numbers we ended up with as a quick new setup after the testing you see below. This was based of a fuel may we got from EFII as their standard. It was still a bit rich in my plane. We are going to need a good day of runs  at different RPM up to the higher ranges to set the whole map but the one above is ‘usable’ for low RPM work.

We did more testing with the new settings, plugs not connected and ignitions off of course. The numbers and cockpit indications were promising.

Time to try again. With an abundance of caution I didn’t even prime the engine. I remain concerned about the VERY expensive backfires. As I cranked Gary watched on checking the numbers. All seemed ok.

After a few more goes the engine was starting well with minimal throttle and idling quite low around 660rpm. Gary was monitoring the AFR (air/fuel ratio) very carefully on each start and we tweaked the low RPM section of the fuel table to the one I displayed earlier.

So the problem was found.  The supplied fuel map with the engine was rubbish. Given the log books say it has been previously run for 25hours, I have to conclude it was NOT with the supplied map I got and an error had been made. These things happen. The fault was in an unexpected place and took 3 months and several thousand dollars to find. Of course its easy to say, “Why didn’t you check this day 1?” A lot of people were involved and given the engine run history as presented, it took fresh eyes.

I always move forward. This is now in the past, gone and behind me.  The first taxi happened the next day.

Following on from Part 1 of this story, things got worse. I hope there isn’t a Part 3. We first waited for the new flywheel to arrive.

My lock wiring has never been very good. It’s become local sport for the guys to see what I’ve done and then point out the faults, and even give a hint on how I can improve. At least they have stopped cutting them off. This is still not ‘LAME standard’ but it is better than it was.  Of course I get to cut them off given the prop and prop extension have to be removed yet again.

Here’s the new flywheel. It is a bit heavier than the old one,1.9kg vs 3.2kg. I was trying to save weight in case I had a balance issue and needed ballast in the nose but the scales and calculations tell me all is well back there. A bit more mass in the flywheel is a good thing. Although any extra weight is not of course as it takes more horsepower to move it.

I moved this ignition trigger one stop to line up better with the magnets on the new flywheel.

The magnet to trigger gap is within spec now of about 1/16″. It was wider with the old flywheel and the magnets were not as well centred. We felt this might be the rough running problem and given I needed a new set of teeth it just seemed prudent to ditch the old one for this.

The expense with it being an airplane part and modified with three magnets was eye watering. It was held up in Wildlife and Fisheries customs for nearly a week after getting here. I remain confused about the likely pathogens that live on metal that might be a danger to entry into Australia. I have to pay a fee for it to sit there. No one told me I needed to pay yet more money on top of the freight, duty and GST. So it sat some more until I started spending a couple of hours a day on the phone trying to sort it out.  Legal theft? We don’t have much tipping or widespread bribes here, call this what you will.

With the prop back on we first wanted to check everything. We got a pin out drawing for the ignition looms and buzzed the wires to ensure they were correct. We rechecked the ignition CDI blocks to ensure they were not the wrong way around. We rechecked the spark plug leads to ensure we hadn’t gotten that wrong. We have done all this before but something has been wrong and we wanted to eliminate every possibility of a fault we could think of.

We even rechecked the new flywheel position relative to Top Dead Centre (TDC) and the number of degrees before this that the trigger magnets should pass the pickup. This shows on the cockpit engine display as T1,T2 S1 S2. We had the positions from EFII support. This all checked out as correct. We were at least confident that it ‘should’ start ok although I admit to being weary now of my well worn optimism which is has been taking a hit with this engine installation.

Here’s the first start attempt. I couldn’t get it going. However the cranking speed was good so we can confirm that problem is solved.

For the next try I gave it two pumps of the throttle which engages the accelerator pump. I’d just done one pump on the last start attempt. Protocol is to then wait ten seconds and then go for another start.

This is what happened. Probably the loudest backfire I have ever heard close up and a dead stop.

If you can read palms, tell me what this means please.

Here’s the result. The gear was stuck out on the brand new starter and six teeth were missing from the previously unused flywheel. Houston, we have a problem…still.

In fact an even bigger problem than I thought. Not only flywheel teeth gone but that event took out the new starter motor as well. Dead as a doornail. You can see above two teeth are out of that internal starter cog. It has a shear pin to prevent this problem, for whatever reason that pin is intact and the starter isn’t.

I am extremely fortunate, at least with some things, that the hangar guys took care of the starter and had a new ring in stock. The old one gets ground through almost to the edge and then a hit with a cold chisel gets it off. The new ring is heated up as you see above and just slips over the flywheel. You can have the flywheel in the fridge first if you like. I hadn’t seen this before although it is a standard practice.

Of course I wasn’t going to get off that ‘lightly’.

One of the prop bolts galled when trying to get it out. That thing was really stuck in there.  It eventually was teased out with a lot of forceful technique. Someone bigger than me did the hard work here.

Of course the insert was also toast. I now have the repaired flywheel and starter reinstalled although not torqued up. I didn’t have any spare prop bolts, let alone an inset so these have been ordered and will come from the USA in a week or more, customs permitting.

I was previously meticulous in cleaning the threads and using a little light oil. That didn’t save me. I am getting a 1/2″ UNF tap and die and from now on all bolts and threads will get the run through. I am going to use anti-seize although people say not to. My plane, my call. With 50’lbs of torque and lockwire I consider this as safe as I can get it. I’m not going to have galling again if I can help it.

The fun is not over yet. I bought a borescope as I wanted to check inside the cylinders and for other hard to see places.

Rust…

More rust.

These are cylinder walls covered in rust. This engine was not preserved. It should have been per Lycoming instructions before shipping. The lack of smoke on the very first start should have been a clue. Apparently if preserved per specs, fluid should drip out when you remove spark plugs . This didn’t happen. The engine was delivered with desiccant spark plugs which is to remove moisture. I assumed things were correct.

To be fair I could speculate as that because you are meant to ship things without fluids this was why it was empty. However, I would need a heads up if things were subject to rust with zero protection. I assumed it would have been sprayed or coated internally somehow. The evidence show this engine has been sitting around for a long time indeed. If this was a standard engine, I’d get the cylinders off relatively easily, however we have quite a different beast here and I’m going to push ahead and see what some running does. I am extremely concerned that we might have rusting deeper in the engine. This would likely cost me a bomb and maybe a year.

Meanwhile, I have these parts back on while I wait for prop bolts and the new insert.  We can get a strobe timing light on this and check that both ignitions are firing where they should just by cranking the engine over with some plugs out. This might be a job for next week. It is back to the waiting for parts game AND we still need to find out what’s wrong with the timing of this engine ignition.

We have to find something before I will risk another start.

July 21 2024 This was our first attempt at starting the plane. An exciting moment. Simon, my super capable avionics/electronics guy was on hand. He is also a pilot and aircraft owner which adds to the pool of knowledge. Darren my long time friend who had helped with some of the big layups on the plane was operating a phone camera to record our success.  It turns out physics when applied to aeroplane engines doesn’t care about optimism.

As you can see, an epic fail. For a start, the cranking is really slow. The energy from the batteries is losing current by the time it gets to the starter. We tries both batteries separately and then together (in parallel) which is available on the panel. No luck. I have 4AWG size cables and the voltage loss is too much for this very large tight engine. We thought at the time this was the only problem.

We got the battery cart out and applied power directly to the starter motor bypassing the plane’s batteries and start button. It was really the old school “Contact” with the jumper cables to get the start. You can see even with all that power to the engine starter it was struggling. I had a bit of work to keep it running too and what’s with the backfires?  It seemed to run OK and idled very well down low but it wasn’t sounding smooth. We put all this down to the preserving oil getting cleaned out on the first run.

We were wrong.

We thought the issue must be the cable size. I ordered 2AWG CCA cable to replace the 4AWG throughout the plane.  This was no small task and it took a couple of weeks to get cable from the USA. This is a lighter weight copper clad aluminium that has less voltage drop that pure copper and less weight. It is slightly fatter however which added to the installation challenges.

I did mention this job in a previous post but here we are again for context.

My batteries were not in perfect condition and one was charging poorly. I bought two new HC20 which have more CCA (cranking amps) and supposedly the same foot print as the PC680’s. No they don’t. An hour or two carefully rounding the corners of the batteries had them fitting in my holders.

21 September 2024 With new cables and new batteries, without the spark plug leads, we cranked it over in the hangar. It did crank faster and we thought OK, job done. This is not going to break prop speed records but we felt it should start the engine. Job done.   …….but it wasn’t.

We had also addressed another huge issue. Clearly from the first start we could tell the timing was wrong. How could this be? The engine had been run for 25.2hours before delivery. Well a few of us had noticed that there was zero wear of the flywheel AND the starter motor. The engine builders must have used their own for whatever reason and bolted these on before delivery.

The ignition is triggered from three magnets imbedded in the purple pulley ring you see above, This is in turn bolted to the flywheel. Quite a few emails went back and forth to Robert Paisley at EFII. Robert is fantastic at support and one of the many reasons I went with his EFII System 32 ignition and fuel injection.

Eventually we got the numbers of degrees past TDC which we could measure. At a certain point when the ignition is triggered it shows on the engine monitor. Well to our, lets say, ‘surprise’, this was nowhere near correct. The magnets were in the wrong position!  No wonder we had a problem starting. The flywheel came off and we got the ring orientated correctly, there are a few ways you can bolt it on and it was 180 degrees wrong. This took a bit of head scratching as the email instructions seemed a bit cryptic, it is a hard thing to explain in words.

So we had found the problem and were confident that the next start attempt would go well.  <sigh> Read on if you want to.

We tried to start but still had a problem. The cranking wasn’t all that fast, even on both batteries, and it just would not run. There was also a loud clicking noise. During our attempts it looks like the starter on one of the backfires kicked out a tooth on the flywheel!

So we still have a timing issue and I need a new ring gear, but there was something worse yet to come.

Yes the engine groans, perhaps ironically. I’d been aware of this really tight spot where this sound is since I got what sometimes feels like a $100,000 brick. Given my plans, I really thought I needed to ask the engine designer about it. A few people has said its just a tight engine and this is not uncommon. That is until they heard the noise. Well I was told I needed to find out what it is and that I should do a bulk strip of the engine. In Australia you are looking at $30,000 to $40,000 and maybe six months. GA has declined here with engine shops being in small numbers now and long waiting lists.  I was not happy.

I was lucky to have ‘The Engine Whisperer’ working in the hangar. He spent some time on it as a person who has many years with these things. He could tell by feel that it wasn’t rings but either thrust washers or main bearings. Apparently you can tell by the amount of play relative to the sound when you move the prop. It was still a bulk strip.

He then measured the endplay which came in at .0015″. Lycoming says .002″ to .006″. Given the tight tolerances of this design and a pretty rough measuring dial gauge setup we can call this good. Zero play would have been a big problem.

After some reflection and the next day there were another series of prop wiggling and listening for a new diagnosis. The sound wasn’t loudly present that day although the tightness was still there. An ear to the rocker covers found the problem.  It is the rockers moving in the new bronze bushings that have not bedded in that is causing the squeaking and the tightness at that spot. Apparently this is common on newly overhauled engines on their twins which have a similar size powerplant to mine.

As this was a familiar problem, with the source of the sound isolated, I’m calling this one solved and I can sleep better at night again. For once, the engine will self heal. Meanwhile we still have the no start issue.

You might need a few plays. We get down to 4.49 volts and 499.7amps!!! OK, momentarily but this engine is NOT happy. The tight spot is probably where the peaks are.  What is going on?

After lots of discussion about what to do next we thought we would try a bit of a scattergun approach. That is when you just start replacing things after no clear idea of what the problem is.

The Chief Engineer in the hangar had gabbed a starter motor from the store and offered it as something to try. A very generous thing to do.

Here’s the old starter, which has had less than 60 seconds of use in total. Clearly never used in the previous engine running before delivery. Its a B&C and I don’t think its faulty. It is string enough to break a flywheel tooth after all!

Here’s the new SkyTec starter. Just under a pound lighter and very surprisingly despite the longer footprint, there is room to fit it.

Simon did the bulk of the work to get this thing installed. We had to play with the main cables a bit and find a new link to the alternator but we got it done.

Here we go with the SkyTec. I don’t have video of the meters but peak current was nearer 200amps and voltage drop not lower than 6volts. You can see the prop isn’t going to break the sound barrier at the tips with its rotation speed BUT it is hugely improved on the old starter. I think this one should work.

The SkyTec has a permanent magnet rather than an energised field, I wonder if that’s the difference? So I have rotation speed with my own airplane batteries and the cranking might be sorted out. I think the current drop was causing the B&C to retract just momentarily and throw out the starter gear and that’s what broke the tooth.

Lets go back to this picture. Given we still have the timing issue I sent this shot off the EFII. We think we have the timing ring in the right spot so what’s up?

I’m told that the magnets don’t line up with the pickup dead centre. OK I tried to move the pickup but it has no sliding adjustment. The magnets were also placed a little off-centre in the purple ring which adds to the problem. It further turns out that the magnet to pickup gap should be 1/16″, my gap was 1/8″! I can fix that but not the other problem.

I need a new flywheel gear given the broken tooth. I have a Skydynamics lightweight flywheel with a custom fitted pulley ring. Given a few factors, the magnets are slightly off centre, this flywheel gap is a problem, my weight and balance issues with extra weight at the back turned out to be unfounded, I can take a regular weight flywheel.

A new Superior flywheel with installed magnets which are standard from EFII is in the mail. Will this be the answer to solve the timing issue? You will have to all wait, as I am, for my next blog post to find out.