Cowl Fit (2)

The next step for the top cowl was to sneak up on the firewall fit so I could match drill it to the hinges.  I think I probably had the thing off and on a good 30 times.  I'll eventually need to even out the gap, but for now I just made it close to flush with the firewall.  I've been told it's easier to get a consistent gap after both top and bottom cowl are all riveted to hinges and fit to each other.  Then the trick is to glue a piece of sandpaper to an old credit card or hacksaw blade and run it in between the firewall and cowl.  That gives about the right gap to allow for paint and a little movement.

Once I had the cowl fitting fairly well, I laid out the rivet spacing for the hinges (about 1" between rivets).  I taped the cowl tightly to the firewall and then drilled them all with my fingers crossed!  You're basically drilling blind, so I just had to hope all of my measurements were correct.  I haven't pulled everything apart yet, but I think it worked out ok.

With the top cowl attached to the firewall, it really stiffens up.  I slid the lower cowl in place to get an idea of how it is going to fit and try to wrap my head around how to deal with it.  It's hard to tell where to start, since it is too big and has to overlap the top cowl.  Because of that, everything is thrown out of whack.  I took it off and crawled under the plane to draw a line 2" back from the firewall, just like I did for the top cowl.  The instructions say to start by cutting off the bottom portion, then moving to the sides.  It's just going to be an iterative process.  Slowly but surely, I'll get there.  it's nice to see it all coming together though.  This has been something I've been dreading for a while.  It's going to take me a long time to get everything fit, but at least now I sort of understand how to go about it.  I do think there are a few places around the air inlets that I may have to add on some additional glass (I cut too much off initially), but I won't mess with that until both cowl halves are done otherwise.

Top Cowl Fitting

More catch up writing...

I've had to go round and round with the backup alternator.  Because of the extension required for the 90 degree oil filter adapter, the alternator just won't fit as-is.  I've been swapping out parts one by one for the past month, and with each one I put in, the next hurdle comes into view.  I think I'm finally at the end of it though.  B&C (where I bought the alternator) has an extension kit that pushes the alternator aft by 3/4", which should be enough for it to clear the oil filter adapter bolts.  In order to put the extension on, I have to swap out the existing studs for longer ones.  These studs are in tight!  I struggled with them (using double nuts) for an entire evening, but had no success.  I was really cautious, because the last thing I wanted was to snap one off in the case.  Amazon to the rescue - I bought a stud puller, which after tightening it down to within and inch of its life, was able to get the studs out.  I'm still waiting on longer studs and the extension kit. Once those arrive, I should finally be done with this long, drawn out "30 minute" project.

The EarthX battery has just enough of a different design that it doesn't quite fit the standard Van's hold down setup.  The hold down bar actually touches both terminals.  I put a second layer under the bar, but that was still too close for comfort, so I added in a layer of plastic as an insulator.

Shifting gears back to the cowling.  The next step was to get the firewall hinges in place.  These are 1/8" hinges, but Van's provides smaller steel pins to use in place of the 1/8" pins.  Because of the curve, it would be impossible to get the larger pins inserted.  The smaller pins allow some slop in the hinges, but apparently once the other cowl attachments are in place, it becomes a non-issue. I cut and fit the hinge to the firewall and match drilled them.  This also included a shim to bring the hinge down a bit to match the cowl thickness.  The hinges are offset towards the right side of the firewall - a short section on the right and then a longer section towards the left.  This is done so you can reach in the oil filler door and insert/remove the pins.

The hinge eyes on the cowl half have to be beveled around the curve to allow them to slide together without interference.

There is a short open section to allow room for inserting the pins. I had cheated the firewall side of the hinge material forward 1/16" so that the gap between the cowl and skin will look better (vs having the look of an eye, no eye, an eye, etc showing in the gap).  I also put an extra chunk of material in the open section for the same reason.

Van's doesn't say to do anything with the pin ends.  They're extremely tight, so it's not like they're going to work loose, but I also don't love the idea of them just floating around.  I made a simple catch out of some angle that I'll pop rivet to the firewall.

I put the cowl back on to check the fit against the firewall.  It's fairly close, but is going to need some additional sanding to get a consistent gap.

The hardest part of all of this was simply getting the cowl level so I could do an accurate final cut at the firewall.  There's not exactly any flat surface to reference, and the parts don't come symmetrical to begin with.  To give myself a fighting chance, I leveled the plane at the cockpit longerons by letting air out of the right tire and dropping it about 1/2".  There isn't a good way to put a level across the front because the center dowel gets in the way, so I just measured from the floor to the lower edges of the air inlets instead.  I'll double check tomorrow, but I got within 1/16", which is plenty accurate to not be noticeable.  The one issue is that the horizontal portion of the cowl doesn't hit the firewall equally from side to side.  At first I was using that as my measure of level, but I don't think the sides came cut evenly, because anytime I made the cowl hit the firewall at the same spot on both sides, the front was definitely out of level.  I know I'll have to trim the sides a bit once I mate the top to the bottom cowl, so hopefully I have enough material.  If not, I'll just have to glass on more material to work with.

Cowl Fit

I've still been plugging away, but there hasn't been much visual progress to share lately.  I'm slowly chipping away at the cowl fit.  These parts take the cake for being the most laughably ill fitting parts of the kit so far.  Whereas I'm sure the new planes that Van's is designing probably have everything designed in CAD and then CNC cut out of foam to create the fiberglass molds, I think the 9 is an old enough of a design that the original molds were made by hand.  Today I spent hours and hours cutting and sanding to get the nose bowl at least close-ish.

Given the shape of the nose bowl, there's really no way to make it circular vs oval (the picture above makes it look far more circular than it really is).  The center points of the halves don't even line up between the top and bottom cowl.  By the end of the day, I decided to just move forward.  I'll have to reshape the curves to match the spinner after everything else is sorted out.  It will look fine in the end, but just needs a lot of TLC to get it there.  I attached the 13" disc to the nose bowl and put the cowl back on the plane to look at the fit at the firewall.

The next step is to attach the piano hinge to the firewall for the top cowl.

CO Detector, Cowl Fit

The miscellaneous accomplishments of the night:

I don't like that the backup latch at the top of the canopy swings under the roll bar and doesn't have any barrier to keep it from banging against the paint.  Since this is just a backup up catch to keep the canopy from lifting if the main hooks fail, I thought about just setting it up so it didn't touch the roll bar at all in normal use (although if the canopy does try to depart, I don't really care if the latch destroys my paint keeping everything in place!).  I can see myself accidentally swinging the latch around before the cockpit is fully seated though, and in that case it would gouge the roll bar pretty good.  So I dropped the latch down about 1/8" below the roll bar height and installed a strip of UHMW on the aft roll bar channel.  This at least gives me a little protection.

Next up was installing the Aithre CO detector.  It's a super lightweight box that can go anywhere in the cabin.  At first I was looking for a place to bolt it, but it's so lightweight that I decided a strip of adhesive velcro was plenty (and in turns out, that's an option in the install instructions).  I put velcro on the cross bar forward of the subpanel and slapped it in place.  I actually prefer this approach because for anything hidden by the subpanel, maintenance involves crawling underneath the panel.  If the CO monitor has to be taken out, it's going to be far easier to just pull it off the velcro than contort myself to undo nuts and screws.

I spliced the power, ground and data wires onto longer pieces and ran them up to the Backup EFIS Dsub connector on the ACM.  Getting to the ACM connectors is easier said than done with all of the wires in place now, so I took the easy way out and just removed the PFD screen.  That gives easy access to working behind the panel.

Once it was all wired up, I configured the MFD for the monitor (serial port 2 on the MFD) and set some basic alert levels.  Anything in the caution or danger levels will have alerts that show on the screens, as well as provide audible warnings.

I believe that's actually the last bit of wiring that has to be done behind the panel itself!  There's still all of the engine sensor wiring, but that's already in place and is just a matter of cutting wires to length on the engine side and connecting to the sensors.

Now comes the part I've been dreading...working on the cowling.  I made the first cut on the top cowl to cut it to length so the fit is fairly close to the firewall outline.  I came very close on it, but it looks like I got off about 1/8" in one section where the firewall changes angle.  So unfortunately I'll have to do some surgery there and add a little fiberglass to extend it again (it's only about 3").  Given the horrid state of the cowl, I'm going to have to get used to doing fiberglass repairs.  The fiberglass parts are the laughing stock of Van's, and I see why.  It's going to be a nightmare to make it all fit together nicely.

I spent an hour slowly sanding away the flanges of the nose bowl where the top and bottom cowl nest together.  While I got it close-ish, it's still horrendous and has a long way to go.  I just need a decent fit for now so I can start to work on the hinge connections and firewall connections.  Once that's all done I'll come back around to making it all pretty.

Canopy Latch and New Purchases

I haven't gotten much done lately, mostly because I've been waiting on random parts or hardware to arrive.  Today I finished up the backup canopy latch.  This is just a bar that rotates under the roll bar as a backup to the main canopy latch hooks.  I'll have to figure out a way to protect the roll bar from the latch.  As-is the paint on the roll bar will get destroyed pretty quick.  I have some 1/8" UHMW plastic that I might attach to the roll bar for the latch to seat against.

I measured the routing for the throttle and mixture cables about 1000x over the past few weeks and finally bit the bullet and ordered them from McFarlane.  Technically I needed 46" and 47" cables, but the choice was to order those lengths as custom builds or just try to make do with their standard 48" cables.  Given that the cost of the custom lengths was 2-3x as expensive, I decided I'd figure out how to deal with a little extra length!  McFarlane now makes a new type of vernier cable that is all the rage called a vernier assist cable.  It's hard to explain the difference, but it essentially makes large push/pull actions doable without needing to push a button, like with standard vernier.  It still allows fine adjustments by turning the knob as well.  I received the cables today, and they are definitely the best of the best.  They are buttery smooth compared to other cables I've tried.

I also broke down and bought a CO sensor that can integrate with my AFS screens.  These puppies aren't cheap, but the alternatives that people use are iffy at best.  A lot of planes use the "black dot" sensors that are just cards that change color when the CO levels reach a certain level.  Considering once the levels reach that point, you're impaired enough to not make good decisions, I don't see the safety value of a device that you have to just happen to notice is slowly changing color.  The Aithre sensor will trigger visual and audible alerts on the EFIS, which seems far safer to me.

I was going to finally get the backup alternator installed today since I received the hardware I needed.  Unfortunately, even with the new oil filter spacer block I got from Titan, the alternator won't fit.  I emailed B&C to see if they have any other options to make the alternator fit.  If not, I'll have to return this one and try to find another alternative.