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Friday, 17 February 2023

Finishing / installing the firewall, rehanging the engine (for the last time fingers crossed)

 This has been a long journey.  The build overall has been long, but the 'engine' journey from idea, to fuel system design and fabrication, engine mount, electronics placement, firewall decisions, firewall construction, engine on and off, etc has been 2 years.  But, to see parts made 1 and 2 years ago come together is pretty darn cool.

While I am waiting for parts (more Ocrotek tape and 1 fitting), tidying up the wires, and adding a few more for later use.  Might as well do it now while it is somewhat 'easy' to get to.  Plus, tightening down and torque sealing all the bolts, brake fittings, etc.

Firewall went into today... hopefully for good!  Was relatively easy... just a bit of prodding here and there to get it to seat into the fuselage.


The hardest part was fishing the wires through correctly.  This wasnt that big a deal, except the EarthX battery jumper cables have to go through the opposite way because of the fusible link.

Next step is the fire barrier on the edges.  I am taping everything off in stages so hopefully I can just let it gel, then pull the tape and have a nice line.  I went with the 'gray' 3M Fire Barrier 2000+.  Hopefully it looks OK.


Clecos in (for positioning, not that it was a problem - it all lined up perfectly after some gentle persuasion with a fist or two) and 2 or 3 lines of tape all around.

Fire barrier inserted between the firewall flanges and fuselage shell.  I clamped in a couple areas where the clecos were not enough to snug it up enough.


Air deflector riveted and screwed in place (very thankful it still fit, as I drilled it over a year ago).  Also all gooped up with fire barrier.


Next is riveting the flanges to the fuselage shell.

I set somewhere around half the rivets on the flanges / shell, and replaced the hardware on the gascolator mount and safety wired the screws.  Working on hardware selection to permanently bolt the firewall frame up to the cage tabs.  Its starting to get 'real'.



Once the frame is bolted in, then I can (re)do all the power wires, place the batteries, etc.

Progress.  A couple of evenings and I have a lot of stuff bolted in, and wires (hopefully) run for the last time.


Its starting to look like something.  Lots more to do... but the weekend is here!  Hoping to get everything alive by end of day Sunday.

My inspector is really big on silicon boots (aka nipples) on all power wires... and of course I just ran out.  2 short.



Almost there.  Everything is functional at this point again (but only one battery).  Pumps work, new starter relay works, everything through the firewall, etc.  Lots of little things to do.  Some fasteners to install, couple holes to drill, some rivets, etc.  The interior of the panel can be reassembled as well.  All of the fittings on the aft side of the firewall are populated.  My goal is to get as much done as possible before the engine mount goes on.

Small issue with battery cables.

For my electrical configuration, the output of the main relays are bridged - IE they go onto a common bus.  Because I want to be able to start off of either battery, the cable between then is a 2 gauge.  Plus I have to tie in the engine bus, ACM, and fuse panel, plus the UL smoothing capacitor. Bottom line, there is a lot of stuff on the output side of the relays... and I have to add one more for the starter, and I just don't have enough threads left.  

The thought:  2 terminal distribution block that I can tie in the big 2 gauge lugs, and then split off to the starter.  All this means is the problem will not get worse.  Need to find one that can handle a couple hundred amps.  Then there is the issue of mounting location... I am out of room in that area, so it will probable have to be mounted to the engine mount with adel clamps.

Ready to re-hang the engine...


I took the opportunity to weight the beast before and after using racecar scales.


It wasnt quite perfectly level, but very close.  Doesnt really matter for these purposes... what I wanted to know was the engine weight.

And the numbers are....


268 lbs for engine, exhaust, induction, starter, alternator / generator, etc.  No baffles, intercooler, oil cooler, etc.  An IO-390 weighs 310 lbs bare (no exhaust, no alternator, no starter, etc).  Note:  I forgot to take off the front travel plate (that mounts to the floor of the crate) when i weighed it.  Its at least 2 lbs with hardware.

Couple points for anyone looking at UL:

  • Turbo:  You need to adjust the angle of the turbo outlet before mounting the engine.  In my case, it was pointed straight up.  Also, you have to remove the oil return line in order to spin in.  Dont forget to tighten it back up (note to self).
  • The main oil return line to the sump interferes with the right lower engine mount.  I need to 'finesse' it a little.  
Back in the garage, ready for the next steps.


Next steps are:
  1. Engine umbilical to ECU, firesleeve, etc.  Retest wiring.
  2. Oil cooler mount, cooler, plumbing, etc
  3. Baffles / plenum / intercooler ducting
  4. Intercooler plenum and hoses
  5. Cowl (oil cooler opening), reshape cowl for larger spinner
  6. Exhaust extensions
  7. CHT / EGT lines
  8. Plug wires
  9. Fuel delivery and return lines
That's enough.  My head hurts.

Onward and upward...


Cabin Heat

I have had the cabin heat valve for almost 2 years, and it has been placed on the firewall for at least a year.  I've also had the push pull control for it.  The hole in the firewall has been drilled for it.  So why is it not done?  Great question...

The actuator for the valve is on the firewall side and moves horizontally.  So I need to do a 90 degree transition on the cable.  I have had some rough mounts for this ready for quite a while, but never finished it.


So here is the contraption... bell crank arm to do the transition, that is mounted top and bottom off the firewall frame for the pumps, filters, coils etc.  It just simply transitions it 90 degrees.  Just has to go around all the rest of the crap.

The arm has an AN-4 bolt through the center.  The rod between the bell crank and cabin heat box is just a 1/16" piece of stainless from the control cable.  Not fancy.

Finished product... need a shorter bolt, and I ran out of AN4 castle nuts.


The cockpit control is a McFarlane locking unit, custom engraved.  Works like butter.


Excuse the mess.  Construction Zone...




Wednesday, 1 February 2023

Waterline / Doorframe Jig

So another little project that is long overdue.

Since I am not the original owner of my fuselage, the waterline was already marked (sure hope its right...).  But, from an ongoing perspective of being able to level the fuselage when needed a simple jig of aluminum angle gets drilled into the doorframe so it can be clecoed in when needed.  Just pull back the door seal, and cleco it in.

Been meaning to get this done for ages.  I have been leveling everything with my digital level off the marks on the fuselage... but with all the body work I have had to do, the line is getting faint :-)

The angle that I am using has been used many times... for clamping / gluing the trailing edge of the elevator, ailerons, flaps, and even cove skins.  But, its long enough that I can line up the waterlines, trim and drill (and then mark very carefully where everything goes, and hopefully I dont lose it!).  It is definitely going to need some cleanup... 

Initial placement.


After trimming and drilling and aligning...


Done...





Now the trick is to not lose or misplace it when needed...