Ch 23 Engine Installation

Date:  03-03-2019

Number of Hours:  9

Manual Reference:  no ref

Yesterday and today I kept on with ramping the internal edges of the armpit scoops with permagrit files and sandpaper.

It was surprising how look this took.

I knew I was done when both scoops were smooth and even to the touch. Ideally it would have a 7 degree or less slope. Mine is more abrupt because I will have diverters, dividers and baffles of some sort in there. I’m content to just have a good flow through the mouth to the scoop floor.

This intersection I knew would have to be addressed. The cowls were bent inwardly and no amount of heating or forcing into place seemed to work when I installed them.  Today I sat and stared for a while and now I know how to address it all. It will be wonderful, trust me.

After trimming both scoop edges I worked for the fit, 0.75″ from the sides and top. I just needed to hold them in position and then check and check again that we were good. Boxes, books, foam and tape, whatever I had lying around did the job. I made a .75″ spacer for the top that also helped.

Once I was happy, out came the hot glue all over the attaching edges. Soon I could remove the pile of stuff holding it in place.

Next up I checked my gaps.

Then checked again.

All was good and with the hot glue doing the holding, I drilled and installed a nest of clicos. Once this was done I took all the clicos off and detached the scoops from the cowl. I then removed all the hot glue and clicoed the scoops back on again. Then I rechecked the gaps and position. Yes we were still OK.

I again removed the clicos and scoops and this time, knowing my position was good, did a final surface prep. I mixed a batch of epoxy and added pure to both surfaces. Then came a batch of flox, I lined both surfaces and clicoed them together.

As the final step I drilled and added a few more clicos in places where glue squeezed out when I pressed the edges. A nice porcupine look ensued and after a clean up I headed home after another long day.

Date:  02-27-2019

Number of Hours:  12

Manual Reference:  no ref

The Mike Melvill cowls come with armpit scoops. These arrive in pieces and its up to the builder to join and fit them to the cowls.

This is what you get and they are close to fitting.

I first sanded all the surfaces dull. There will be tapes and ramps and who knows what. I do know that a dull surface is going to be easier to do now than after they are attached to the cowls.

Next up I very carefully joined the halves using hot glue.

One inch 2 ply BID tapes followed on the inside joins.

After cure and peel ply removal I had clean solid joins. Even so the hot glue stayed on the outside. You might notice that the entrance lip is hollow on the inside. I think this will cause turbulence and its a relatively easy task to fill them now.

Lots of that crazy pour foam went in. About 6 layers of 10-20 grams each batch.

After a careful sand we have ramps from the lip to the scoop floor. Its a bit hard to see in the pic. I’ve just made a graduated slope. A little filler can be added later to make it perfect.

After a measure up and a think I’ve gone for one ply where the pour foam is and two ply tapes on the outside edges. Yes I did remove the hot glue and prepped the area first.

All done with peel ply. A big clean up tomorrow and this little side job will continue. I might mention it was 37.5C outside today and about the same in the big tin shed that is my rented hangar space. I’ve noticed complaining doesn’t help the build go faster.

Date:  11-15-2018

Number of Hours:  8

Manual Reference:

The underside of the top cowl lips needs a couple of plies of BID at the firewall and spar. Pretty straight forward, but it always takes careful prep and a little time.

The usual layup or foil. The small pieces are for the lip at the spar where I’ve cut it so that the wings can still be removed. I felt the edges could be reinforced.

This is the lip to spar underside getting the BID.

The rollover also got a couple of plies inside lip. Its really about preventing delamination (delam) and it makes the lip stiffer.

I’d been adding filler to the rollover to try and get a perfect line. I went over the join and thought it would be easy to sort it out after cure. Yes easy, plus two hours I’ll never get back. I had to dig it out at the edge. The above pic is a more careful application of release tape and redoing the intersection.

It worked out OK and I’m on my way to a clean line.

This is more like the release I need. I’m doing one side with filler, letting it cure and then re-taping for the other side. This way the canopy doesn’t get stuck. I’m a slow learner but very persistent.

Date:  11-11-2018

Number of Hours:  8

Manual Reference:  23-2

Having done the inner lip layups I began removing the top cowl. Then I realised that now would be a good time to put the clecos in, before I did the release with everything sitting as it should.

I spent quite a while spacing them but in reality I may move positions later.

I’ve ordered 50 sets of camlocs and won’t have many left over.

The sides gaps got a little flox to see how it went. There are a lot of small detailed layups to get this install as it should be. A tiny amount of filler will work out.

I trimmed the edges and this is closer to the final look at the sides.

It looks more like a plane now.

Getting the cowls off took a while. The parts with this heavy PVC mould release worked a treat. It took hours to get enough layers with a good 30mts in between each to dry.  This is a great new technique when grey release tape won’t sit properly, as long as you have the time.

This was right after the cowls came off. A couple of hours was needed to get them removed. Yes the layup needs a good trim. I’m happy with it, given it was done without being able to see very well. The bottom cowl certainly fits. Its not a perfect line at the sides, just something else to fix later.

This is where the main cooling intakes will go. How this is going to work I’m unsure. These may bond to the cowls or maybe the cowls will bond to them.

The lower lip is the new one. I’m going to do a small layup and join upper and lower at the prop end to give added strength. (In fact I’ve tried it once and didn’t like the result so I’ve removed that layup and will go again tomorrow)

Just showing the width of 18″

I have some area here where perhaps the radiators might go.

This is the end lip that was bonded to the top cowl.

Fits OK given how wild it all was a few days ago.

Cowls ON and removable!

 

Date:  11-09-2018

Number of Hours:  8

Manual Reference:  23-2

With the top on and the bottom cajoled into place using hot glue and sticks its time for the inner lip layup.

Before we go there, I did try for several hours to get the cowl into a better position with a heat gun. I had that gun at well over 200C and the cowls too hot to touch but that didn’t move them a millimeter. I think if the whole plane was carbon fiber like this and whatever epoxy was used I could paint it black, leave it in the sun all day and nothing would creep.

I again went for the mould release rather than tape. Its not pretty, I only did about 4 coats. That turned out to be less than optimum. (Mold or mould? depends on where you live)

This is ugly building beyond description. A real, “do whatever it takes” to get a result approach.

A few sticks, some hot glue and I even needed 5mt epoxy in a couple of places.

I went for a 6 ply layup, plans say 5. I have my reasons, like the sticks which will have to be removed.

While I was at it I trimmed the edges a little closer although not to the final position. I tried adding flox with some carbon dust to see how it might go as a ‘filler’ experiment. It made me feel better about the fit too!

Here’s the right inside lip. The bottom half is where the ‘release’ will be, the top half should stay stuck to the top cowl. I spent some time trying to get all the air bubbles out. A few small ones in the bottom can only help the release later so I was not as fussy although did go at it for a while after this photo. I guess I can’t help myself.

While I had a long way to reach in, with the foil method it was quite doable despite being unable to see what was happening after the curve. If I’d taken the engine out first it would have been easier. Then again it would be really hard to take the engine out without the crane that was still unavailable.

Date:  11-06-2018

Number of Hours:  13

Manual Reference:  23-2

Over three days this lower cowl install has been one of the more difficult challenges on the build. I don’t know why. Its probably me just missing the trick to it.

I have no cutting table so I’ll keep using the floor. I unroll fresh plastic so its clean and then label that side. No matter how clean I make the floor the reverse side is not usable for putting glass on.

I tried using release tape on the cowls. At this point I’ve removed all the heavy peel ply, which is a job in itself. The usual grey plastic tape would peel off and curl after an hour, it just wasn’t sticking to the carbon. I drove home and got some mould wax and PVA green release liquid. I did about 4 coats of the wax and then spent a few hours doing about 8 coats of the green the next day. I wanted it thick like tape, which is what I finally got. The usual 2 coats on wax I think would not release well due to the deep weave in the carbon. Yes I will have to get that wax off later… fun to come.

I just couldn’t get the bottom cowl to sit and decided I needed to trim the top one. That helped a bit.

I got it to this stage a couple of times and used the hot glue to set it but it would pop out again. I tried the heat gun to get the cowl to play nice, it just didn’t work. I tried more cutting and trimming for some hours.

Eventually I resigned myself to gaps at the wing join and the cowl not fitting nicely in line with the fuselage sides. I can fix both things later. The side gaps you see above are easy. The fuselage lining up will be a little more challenging. Getting it to sit was still not easy with blocks and hot glue as you see above.

Quite a gap here. If I had a second bottom cowl I wouldn’t trim the sides at all. I’d leave them wide and place them on the outside of the wing. Fit in place and then consider the trim right at the end when you are 100% sure all is good. I thought I was OK when I did it but not so.

Finally I had a cowl on and reasonably as straight as it would go. That thing is not perfectly symmetrical  just to add to the challenge. This was into the evening with the last part being to put on the tapes.

The wing and upper spar tapes were easy enough to place.

The tape on the firewall took a little digging and diving. If the engine was easy to take off I would have. The crane is in use in the hangar at the moment so that wasn’t an option. Frankly its not that hard to reach down, especially using the foil and plastic method.

Its on, thats the main thing.

Hard to tell in the pic but it is as straight as I can make it. I’ll give it a couple of days to cure and then still a bit more work to secure the cowls with some cutting and trimming. There is the top rear cowl lip layup and reinforcing of the existing tapes. This has been tough, I hope if you are doing these cowls its somewhat easier for you and you make less mistakes than I have.

 

Date:  11-02-2018

Number of Hours:  12

Manual Reference:  23-2

The bottom cowl fit is a bit of a nightmare. I’ve put more than two full days into it so far and just getting closer. The cowls as supplied and my plane don’t match. They are a bit too wide at the firewall and not even close anywhere else. My spar, wings, strakes and firewall are not exact to the millimeter in their respective levels. I doubt anyone’s ever are. If yours are, my congratulations tinged with mild amazement.

Meanwhile who cares about other peoples skills? I am adverse to the comparison game and the need to be better or even keep up with others. I’ve learned over time to not even allow those thoughts to linger. The job is to fit the bottom cowl.  I don’t need any negative mental chatter. Lets quietly get this done. That means ‘at it’ every day.

Here’s what we have to work with.

Ok, its also like herding cats blindfolded. <grin> Those old computer and phone books I’ve used through the build and are great spacers, easily adjustable. Those have to come out each time I move the cowl for a trim. Oh and you might not a bit of wood on the outside on the left on the fuselage to help fitting.

I’ve been on and off those books I guess 30 or 40 times in the last two days. That spinner has been great for getting the cowl centered and ensuring the opening is even upper and lower relative to the middle of the crankshaft.

This was an early big trim. From here I’ve just been taking .05 to .1″ off each time to get the sides closer. I’m very mindful that taking too much off is not going to work out well so I’m being very cautious.

As I keep removing material and resetting up the positioning I am getting a feel for how it wants to sit. You can’t just lop a bit off the sides per a measurement. As one thing moves so do others. The fit needs to be seen as a whole.

I’ve now trimmed the top cowl a little and later did some of the bottom. I have wooden blocks hot glued to the outside to help the fit. As I continue today I’ll be hoping to get to the point of hot gluing the cowl in place from on the outside so I can do the internal lip layups. Its nearly there.

I’m working hard to try and get a relaxed fit. Because one side is a bit proud of the firewall vertical line I’m going to have to force that bit in. After the internal glass lips and cure I may try a bit of heat when its clecoed in place. During all this I’m very mind full that these cowls are going to come off and on a lot. While it may not be pretty and a perfect flush fit initially, I’m trying my hardest to have a good result.

 

 

 

 

 

Date:  11-01-2018

Number of Hours:  6

Manual Reference:  23-2

The front blister fairing required an inner lip laid up from underneath. Just a 5 ply tape. I baby sat it for an hour or two and it was marginally better than the previous. Not a lot to see in pictures.

Here, after cure and getting the top cowl off you can see the blister fairing lips.

They more or less join with the other lips.

Despite this being very ugly, the top cowl sits and fits really well. Most of the lip will be cut away later after the camlocs and I still have an underneath support layup to do. Yes it needs a little fill here and there. It does feel really good to get that top cowl sitting so well and the clecos line up and drop straight in place without a problem.

This was not the easiest thing to figure and build. Now its mostly done, its all good and in the past.

Date:  10-30-2018

Number of Hours:  11

Manual Reference:  23-2

The Mike Melvill cowls I’m using are unusual in that they have a gaping hole each side near the canopy. This turns out to be so that air flowing over the strakes  can get to the cylinder bumps more smoothly. Its also a nifty place to stick a couple of vent lines and who knows what else.

Just before we go there I’ll show you how the lip layups worked out.

Pretty ugly eh?

Not perfect right?

Here’s one side trimmed. OK we have a few gaps. It seems the upside down layup can slowly droop if you aren’t watching it for 3 or 4 hours. I’m not sure how to fix this. Faster curing epoxy? I could have made a fancy jig but other inverted layups have been fine. It may have been the 5 plies and the 3.5″ width. Next time I might risk letting the epoxy go off a little more. Another approach would be to do it in several separate layups with peel ply. Then the weight would be less. I only mention it in the event YOU might be doing such a layup yourself one day. You know who you are <grin>.

Despite this, the top cowl fits really well. The clecos are easy to put in place and it is sitting down well in position without a lot of tension. I’m going to trim and add just a little flox in the gaps. Then after the camlocs are installed much of the existing lip can be trimmed away. So I’m moving on.

This is the hole that needs a fairing. I bought some blue foam to the hangar to carve out some shapes. After 30 minutes fiddling I could see it was going to take too long. I drove home and got the pour foam!

My other considerations was if I made beautiful lightweight fairings, some klutz in the future would put a heavy hand on the thing and it would fail. I could be that klutz! Plan B was this pour foam which is rock solid. I’ll hollow it out a fair bit later to save weight but its still going to be very strong.

Beautiful stuff, it just needs a bit of shaping.

Many hours and one sleep later….

Here’s the other side. The Melvill cowls seem to be about .5″ different from one side to the other. I challenge you to pick it!

To cut the glass out I’m using plastic on the hangar floor. My improvised bench above is just too narrow. No matter how much I clean up the plastic is really a one use item. I’ve gone for a 4 ply layup. Now wait, I know thats overkill but the lip needs to be 5 ply, I’ve gone for 4. If I did one ply on the fairing and then 3 or 4 on the lip I would have had a joggle to fill with filler. I just went with the 4 overall and know that I can really take a lot of that heavy pour foam out later and it will be super strong.

Here’s the foil layup. Of course I’d had the cowl off before the layup, cleaned the edges, recovered in grey tape and prepped the area.

Right side all done and peel plied.

Left side done. I think it looks better than in these photos. Tomorrow I’ll clean up and then have to remove the carbon lip I laid the last 1.5″ on to. Then I make another lip underneath again.  Wish me luck.

 

 

Date:  10-27-2018

Number of Hours:  10

Manual Reference:  23-2

The next step is to create a secondary cowl lip on the cowl lip below. This is to make camloc fastening possible. I’ll thank myself for going the extra mile when its finished.

Here’s the first lip with the cowls removed, which of course took a while. Those gaps between the spar lip and the turtleback lip are for later treatment.

Next up was to trim away where the lip will be. In other words, this area needs to butt against the new lips on the fuselage side.

Once trimmed I added release tape.

Now the cowl needs to be hot glued into place from the top.

The sides were relatively easy to get in position but the rest of the cowl truly has a mind of its own like a living thing. I think it will work out OK. The perfect lines I’d like to see and everything matching up…well this is why I work in fiberglass rather than metal. I’m not so perfect myself.

Where you see the bright light is where another 5 ply of glass goes.

These plies overlap the newly created lip and onto the bottom of the cowl. I found taking before and after the layup photos looked exactly the same. So you can guess if these are before or after. It was a huge job to do this from morning until after dark.

These cowls, not to disappoint, have an additional challenge.  The area next to the canopy has a huge gap each side where I need to make fairings. I think this whole cowl attach thing need to be repeated there so I can put a fastener on it and get a good seal.

Date:  10-25-2018

Number of Hours:  14

Manual Reference:  23-2

Yesterday and today I made more progress.  Finishing up quite late tonight in the hangar.

It took a while to trim the cowl to a reasonable fit at the turtleback.

I clecoed this in place and spent a while getting the sides trimmed to fit.

The very helpful hanger owner gave me a propeller back plate to use as a former to keep the cowl straight. A good thing too as it always looked a bit off due to a slight angle in the carbon pattern. This ensures I’m reasonably centered.

I tried cutting the glass out for the initial lip layups on my improvised bench but ended up on the floor after a good clean up as a better place to lay it all out.

With lots of release tape I started securing the cowl.

That back plate got a clamp and later some hot glue.

Plenty of hot glues sticks positioned the sides pretty well flush with the tops of the wings.

Underneath more hot glue and then the clecos could be removed.

I’ve done 5 plies of BID for the lip per plans in thickness.

The cowl angle is pretty good now.

Here we are laid up and peel plied.

I’m not sure yet how I’ll deal with that gaping hole. Yes it will get a fairing. Maybe just a lip for the cowl to fit into.

At the wings I’ve also laid out a lip upside down. It stuck there pretty well.

Here again is the cowl line. It will need quite a bit of filler just at the top. The sides may be easier to blend. The very top forward edge of the cowl seems to go a bit flat for a few inches. This is just how it came and I may fix it to be a perfect line.

Date:  10-23-2018

Number of Hours:  10

Manual Reference:  23-2

After reviewing all the material I could including Mike Melvill’s instructions and the LE plans, I still spend another two days really thinking about it at the hangar. I finally have a plan.

Here’s the top cowl just sitting at a good angle, aesthetically.

Here is how the top and bottom cowls fit as delivered. A bit or work is required for a perfect fit.

I’ve borrowed a spinner that goes with a Savier ‘Black Bart’ prop. Crazy big right? It was useful in visualizing how the top cowl will sit and I spent a while talking myself into the fact that the engine is pretty much straight. I did a lot of measuring too as things were looking crooked to the left. The measurements however told me the engine is within .05 or within the ‘noise’ of rough checking. After a few hours I decided to soldier on.

As a plan formed. I decided I wanted a 1.5″ lip and marked out the difference.

It was an easy cut with a dremel and a metal cutting disk. I now have carbon fiber black all over me around the safety gear I was wearing.

This is tough to explain. I’ll try. I’m just installing the top cowl first. Plans have you join the two now at the trailing edge. Bad idea IMHO.

I don’t think this will work as well as getting one installed perfectly and then matching the bottom cowl to fit.  On these Melvill cowls there is a joggled lip. Now it needs to go BUT I can use it as a former for the initial top lip on the spar and rollover.

Yes I’m going to make the plans lips then add to them per the Melvill instructions. Although not exactly. That joggle is really 5 plies of BID deep. Interesting.

My spar is sightly lower than my wings now they are all butted up and installed. Just a little, so it makes sense to use this when making my cowl lips. I like the plans method as it has to be strong. I am going to lay up 5 plies on the top of the spar and turtleback into the cowl joggle which I will line with release tape.

Does this make sense? On the turtleback I need to set up the cowl so it sits flush with the edge. To do that I need to make a support for the cowl in line  with the edge. To do this, pay attention, <grin>, I need to set cowl supports lower by the cowl thickness.

That what those stick pieces are on the top of the supports. A stick the thickness of the cowl. On the spar I want the edge to be higher so I don’t need that spacer. This will reduce the amount of filler I use later to get it all to play nicely together and be level.

In this shot you can see the little sticks on the turtleback are not removed. But I did! I just forgot a photo so please imagine it.

When I put the cowl on for the first trial fit it should sit exactly level with the turtleback less the thickness of 5 plies of BID. However it will be proud on the spar or rather when I do the layup between the spar and cowl it will be level. Forward of the spar there will be a joggle on the top spar edge. That’s OK as there is a bit of a dip there because of the curved strakes. Man! This is not a simple build.

I’ll find out how it goes with the first fit. At that point I can look at trimming the edges at the wings for a perfect trial fit. I added some stick there which you can see in the last shot.

On another point for those of you with the Mike Melvill cowls, his instructions talk about making the front edge longer aft so the cowls match the wings. If you got your cowls from Greg at Aerocomposites (successors to Featherlite) then you will see that there is enough extra meat in the way he makes them for this not to be an issue. You can just see faintly on the cowls where the exact Melvill part was and yes it may have been an issue. Gregs cowls give you a couple of inches extra to play with.

This means your lip size is really now determined by the sort of fasteners you will be using. If its camlocs, an inch and a half is a good lip size. Feeeewww!! Got all that?