March 2010 Archives

I installed the rudder cables tonight, mostly because I couldn't think of a good reason not to.  The rudder cables run through snap bushings installed in every bulkhead from F-902 to F-710.  The front end of the cable has en eyelet that is larger in width than the inner diameter of a SB625-7 snap bushing, so the eyelet must be forced through the snap bushing before it is installed in the bulkhead.



Where the cable exits the side of the aircraft just in front of the rudder, the cable passes through a plastic sleeve so that the cable doesn't rub against any metal parts.  The sleeve is held in place by an adel clamp that is secured by the flush phillips screw that is just above and in front of the rudder cable exit hole.  I'm going to buy or fabricate a little exit fairing to hide the plastic sleeve (not because I think it will lower drag, but I think it will look nicer than the plastic sleeve just sticking out of the hole).



I installed the seat belt anchors tonight.  Other than it being pretty cramped where the outboard anchors attach, making it difficult to get a torque wrench in there, these were pretty straightforward.  I clamped a piece of scrap 1/4" thick steel between each pair of anchors and used an AN4 bolt to keep the upper holes aligned while I torqued these down.



Next, I laid out and drilled for the static ports.  I'm using the SafeAir pitot/static/AOA kit, so the flange of the static port doesn't allow you to install them precisely where Van's recommends (11/16" forward of the vertical row of rivets).  The position I used is 2" down from the horizontal row of rivets and 1 1/4" forward of the vertical row of rivets).  Here I'm holding the SafeAir static port in the hole while trying to take a picture.  I had a hard time getting my camera to focus on the static port, so this is a little blurry.



I mixed up a small batch of proseal and bonded/clamped these in position.  I installed the 90º adaptors in the ports before doing this so that I could ensure both of them are pointing upward.  I'm not going to use any rivets to secure the ports since the proseal is plenty strong to secure these.



I fit a piece of the static system tubing between the two static ports.  There is a tee on the right that will allow a single piece of tubing to connect between here and the instruments.



After fabricating the clip that ties the top center rib to the F-707 bulkhead, the lower two rivets can be squeezed.



Next up, I deburred every hole on the fuselage structure (not the holes on the pieces that have yet to be attached permanently to the fuselage structure).  I also dimpled all of the bulkhead holes.



Finally, I played around a little bit with conduit routing under the baggage floors and seat pans.  I'm routing the conduit through the outboard baggage bays since I plan to use the inboard bays for storage.  This also puts the conduit one bay outboard of the area containing the crotch strap and control columns.  This is likely to be a packed area.



I've decided to put storage compartments in the two larger bays below the baggage floors.  After doing some measurements and mocking it up in the computer, I cut a hole in one of the floors.



I fabricated a reinforcing ring that wraps around three sides of the hole.  There will be a hinge along the fourth side.  The joggle at the two ends allows the reinforcing ring to step up onto the hinge so that the corner rivets tie all three pieces together.



After fabricating the door and cutting holes for the hartwell latches, I test fit the floor in the plane.



Here is a closeup of one of the hartwell latches.  They make a crazy number of models of these, but four of the eight I bought off eBay were the same, so I used those.



To open the door, you push in on the button marked "PUSH" (duh)...



and the other part of the latch springs open.



Once both latches are released, the door can be opened.  The reinforcing ring provides a lip that the door can be closed against (and the latches catch under).



Ordered Engine

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I placed my order for an engine today.  I'm going with an AeroSport Power horizontal induction IO-375 with the following configuration:

  • 8.0 to 1 compression ratio
  • Superior cold air induction system
  • Single Lightspeed II+ electronic ignition with direct crank sensor
  • Single Slick magneto
  • Silver Hawk Ex fuel injection system
  • Inverted engine mod (basically some additional internal case machining to better support an inverted oil system).
The stock IO-375 provides 195hp, but the cold air induction system should add 3-4hp.  Total price $27,750.
After vacuuming out all of the metal shavings in the fuselage aft of F-705, I installed the side walls.  These use LP4-3 rivets along the top an AN426AD4-4 rivets along the back.  After I finish modifying the baggage floors for the hatches, they will rivet to the ribs and the lower flange of this panel.



I ordered the AHRS mounting kit from Van's.  This is designed for the Grand Rapids EFIS or the Garmin G900X, but I'm going to adapt it for the Dynon Skyview ADAHRS.  I drilled out two rivets that tied the bottom skins to F-706 and F-707.  These will now additionally tie the rib pictured here.  I then ensured the ribs were parallel and match drilled the skin to the rib.  I then used the digital level to ensure the mounting plate was level laterally and match drilled it to the F-729A rib and F-707 bulkhead.  The mounting plate is tipped aft about 0.5º from the level of the longerons, but this is well within Dynon's 1º limit.  I can always shim the ADAHRS unit if necessary.

I'm still trying to decide how to mount the ADAHRS unit to the mounting plate.  Dynon calls for nonferrous fasteners, but I haven't been able to find stainless steel or brass nutplates.  I can reach under the front edge of the mounting plate, but I'd kind of like to install the unit near the aft end of the plate in case I want to install another unit just in front of it.

Update: I ended up not installing the ADAHRS here because it is too close to the pitch servo and this can interfere with the magnetometer.  I decided to use this to mount the ELT instead.



Since I'm going to mount the ELT on the Van's mounting bracket on the right side wall behind F-706, but put the antenna behind the roll bar, I decided to run the antenna cable behind the baggage sidewall.  I drilled a couple of 3/8" holes in F-706 and F-724 below F-786B.  The cable will also run behind the flap cover and then come up through F-786B right behind F-705.   I then fished a piece of safety wire through both holes so that I can later pull the coax through. This would have been easier to do before riveting on the side walls, but it wasn't too bad.

Update: I ended up not mounting the ELT on Van's mounting bracket and put the antenna under the empennage fairing.



Next up, I drilled 3/4" holes through F-705A and F-706 on both sides of the fuselage and ran conduit.  I'll put a zip tie anchor on the rib and cushion the holes with proseal before buttoning this up.



On the right side, the wires will exit the lower conduit and come up the back of F-706 through an adel clamp to keep them away from the rudder cable.  The ELT wires (other than the antenna cable will separate here and go to the ELT bracket.  The trim and tail strobe wires will continue up and enter the conduit shown in the upper right which makes a straight shot to the tail.  I've intentionally left this conduit long right now while I determine how to terminate it.



Here you can see that the conduit passes through F-707, F-708, and F-710.  The wire bundle will then separate with the tail strobe wires dropping down to penetrate F-711 and F-712 and into the rudder while the trim servo wires will make their way up and into the elevator.  I put the conduit up high like this to keep it about 2' from the Dynon Skyview ADAHRS unit.



I deburred and primed all of the fuselage components that I've finished so far.



After those were dry, I riveted F-709 to the aft deck.



I then riveted the aft deck to the longerons and F-710/F-711.  There were four rivets that couldn't be reached with the squeezer, so I'll have to shoot/buck those.



Next up, I riveted the F-695 gussets to the longerons and upper firewall stiffener.  There were two rivets on each side along the firewall stiffener that couldn't be reached with the squeezer.  I'll shoot those later.



I then squeezed all of the rivets that tie the bulkhead braces to the longeron.



I squeezed all of the rivets that hold together the elevator bellcrank.  I'll have to slip a washer in between the halves when hooking up the autopilot servo, but that will be easy with the washer wrenches.



I also assembled the hatch in the left baggage floor.  Here, I've riveted the reinforcing ring and hinge to the floor.



I then riveted the other part of the hinge and the hartwell latches to the hatch.  Here is how it looks closed.  The hatch closes firmly enough against the flange that it shouldn't rattle in flight.



And it opens just enough past vertical that it will stay on its own.  I'm really happy with how this turned out.  This will come in very handy.



I laid out and cut the notch in the upper baggage wall for the harness shoulder anchor cable to pass through.



I then fabricated a couple of UHMW plastic blocks that will act as the wear surface for the cables.



The #19 holes in the upper wall need to be match drilled in the lower wall.



Finished Baggage Wall

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I positioned and drilled the wear blocks.



Here you can see that the opening in the wear block keeps the stainless steel cable away from the aluminum.



The holes that were match drilled in the lower baggage wall need K1000-08 nutplates installed so that the upper wall can be screwed to the lower wall.



The lower wear block gets blind riveted to the lower wall with a couple of spacers made from 0.040" AL sheet.  I didn't take a picture, but the upper wear blocks are riveted to the upper wall in the same fashion.



The seat backs attach to the seat bottoms with sections of P3 hinge material.  There are three pieces of hinge attached to the seat bottom, and one piece attached to the seat back.  That along with the adjustment mechanism at the top gives you a number of choices for the seat position.  First up, I cut eight pieces of hinge material 15.5" long.



The six hinge pieces that attach to the seat bottom need the center two eyelets removed so that the hinge pins can be inserted from the middle.



The holes were laid out and drilled on one of the pieces according to the plans.  This was then used as a template to drill the other five pieces of hinge.



The hinges were then clamped to the seat bottoms at the position specified by the plans.



The seat bottoms were then match drilled to the hinges.



The aft hinge overlaps several holes that are used to attach the seat bottoms to the seat ribs.  The hinge is back drilled to these holes so that all three pieces can be blind riveted together.



The hinge pieces are then riveted to the seat bottom with AN470AD4-4 rivets (skipping the holes that will also rivet in conjunction with the seat ribs).  I've seen a few builders use LP4-3 here, but the plans only specify those for attaching the seat bottoms to the seat ribs.



Started Flaps

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The next step in the plans is to fit the forward tunnel cover, but since that sits against the flap cover, I decided I wanted to install the flaps first to ensure the cover fits as well as possible.  First up, I drilled and reamed all three ends of the flap weldment to 1/4".



The center flap bearing block needs to be notched to fit over the seat pans and cut in half so that it can be installed around the flap weldment.



Van's published a service bulletin a number of years ago after several people had the jam nut on the flap motor rod end back out and the flap motor disconnected from the flaps.  The plans now specify that the end of the flap motor push tube needs a small hole drilled in it so that it can be safety wired around the bolt that goes through the rod end.  This is actually a pretty hokey way to fix the problem as it subjects the safety wire to repeated flexing which can fatigue it and allow it to break.  There is an alternate approach that another builder came up with described here.  This looks like a much safer approach.



Next up, I installed the flap weldment into the plane so that the center bearing block could be used as a guide to drill the floor and ribs



Here is the lower half of the center bearing after drilling.  I went ahead and drilled through the rear tunnel cover and then marked around the bearing since the tunnel cover must be notched to wrap around the bearing.



The side of the flap support need to be reinforced where the upper end of the flap motor mounts.  I match drilled this to the channel and reamed the center hole out to 1/4".



Next, I fabricated this little bracket which holes the other end of the flap motor mount bolt.



The aft flap cover needs a bracket fabricated to attach it to the floor.



The top of the front flap cover needs this little bracket fabricated to tie the cover to the F-705 upper channel.  I'm really glad I have a bending brake; it made bending this just trivial.



The lower end of the front cover needs this attach points riveted.



The front cover also needs a series of nutplates installed down both sides.  These will be used to attach the flap side covers.



I primed and riveted the upper motor mount reinforcing plate to the forward flap cover channel.



I also riveted the lower attach bracket to the aft cover channel.



Here is the plate that I bent on the bending brake earlier.  It's riveted to forward flap cover and gets a couple of one-leg nutplates for attaching it to the upper F-705 channel.



I installed the forward flap channel into the plane and temporarily bolted the flap motor push rod to the weldment.  I couldn't help running the motor up and down a bit to watch it work.



After ensuring the inner bolt support was properly aligned, I match drilled it to the channel.  It's almost 2 a.m., so this is a good stopping point.



After fitting and drilling the rear flap cover, I fit and drilled the side covers.  This totally encloses the flap motor assembly since the seats fit right up against this.



The rear flap cover gets a bunch of nutplates that are used to attach it to the F-705 upper channel and to attach the side covers to it.



After removing everything back down to the ribs, I vacuumed out the shavings and installed some adhesive zip-tie mounts.  I then used zip-ties to support the conduit between the bulkheads.  I finally got a chance to try the zip-tie gun I picked up from Harbor Freight last year.  This thing is great; it automatically tightens the zip-tie to a consistent tension (which is adjustable) and then cuts it off flush so that there is no sharp point sticking out to scratch you.



I also installed some adhesive mounts along the conduit aft of F-706 and trimmed off the front a bit.



Before installing the seat pans, I need to take care of a couple of final things that will be more difficult with them in place.  I'm installing the primary com antenna under the pilot's seat, one bay outboard of the center bay with the crotch strap.  I drew a centerline on the floor in the bay and then positioned the template far enough aft that the coax can't interfere with the aileron push tube.



I drilled the holes out to the specified size.



Here is what the antenna will look like installed.  This bay is very narrow, and the antenna mounts with a doubler plate, so I'm not going to add any additional reinforcement.



I fit the forward baggage side covers, then removed them to install nutplates on the bottom flange,  The baggage floor will screw down to this flange,



Here you can see how the side cover fits.  The bottom flange fits under the baggage floor and the other three side screw down to side bulkheads.  The flap torque tube will stay exposed in the plane, but it rotates in place, so nothing can catch on it.



Now that everything has been match drilled, the nutplates on the aft side covers can be installed.



I got an order from SteinAir the other day which included a bunch of wire I'll need to start wiring components in the plane.  I ordered about 30' of RG-400 which is enough to do most if not all of the antennas in the aircraft.  I also purchased an adjustable RG-59 three blade coax stripper off eBay.  After a bunch of test cuts, I managed to get the stripper adjusted for RG-400 so that it perfectly cuts all of the various component of the cable without nicking any wires.  I then installed a male BNC connector on the end to test the crimper I bought.

The crimper I have has interchangeable dies.  I installed the hex dies and crimped the gold plated center pin to the stranded center conductor with the 0.068" die (RG-58 and RG-400 both have stranded center conductors for use in the high vibration environment of an aircraft compared with the solid center conductor of RG-59 that is typically used in home cable tv systems.  It's also 50Ω instead of 75Ω impedence).  Next, the connector body is pushed onto the pin until it clicks into place.  Finally, the ferrule is slide up tight against the connector body and crimped with the 0.213" die.



My wheels and tires/tubes showed up today.  I'm using the Grove wheels which have a much higher heat energy absorption than the stock wheels and are actually lighter because they're magnesium.  I also went with the Condor 6 ply tires and Michelin AirStop tubes because both were highly recommended on vansairforce.net.  The tire on the left shows the outside of the wheel.  The one on the right shows the inside with the disc brake.



I also ordered the Grove parking brake.



The wheels came with the brake cylinders and mounting brackets.



I have been trying to decide between the Hookers at $410/seat (with the rotary latch) and the Crow at $160/seat for quite some time.  Safety wise, I think they're comparable, but there are several drawbacks with the Crows.  There are only four colors of webbing to chose from as well as four colors of pads to chose from, none of which match my interior very closely.  Also, the rotary latch is quite thick and I'm worried that it will interfere with the stick.  The Hookers come in 14 colors, with 20 color choices for pads and trim, and the rotary latch is much thinner.  The only drawback is the price.  What finally clinched it for me is that I found out that Classic Aero Designs (who will be making my interior) sells the Hookers and will make matching leather pads using the same material that my seats are made of.  With that decision made, I went ahead and drilled/reamed a 1/4" hole, 1/2" below the outer holes in each crotch strap bracket.  I can't use the stock Van's hole position because the Hooker brackets are longer than the Van's brackets.



I also primed and riveted on the inner flap motor mount bracket and bolted the flap motor in place.  This bolt is secured with a cotter pin since you can't torque it down since that would bind the motor and it needs to pivot on this bolt.  I used some TriFlow lubricant here to keep everything moving smoothly.  This is the same lubricant that I will be using on all of the rod ends throughout the plane.



I decided to go ahead and install the seat belt cables and partially bolt the bracket in place.  The middle of the three AN3 bolts has been torqued and sealed.  The other two would interfere with side rivets, so they'll be installed after the top is riveted on.  I also put the AN4 bolt that attaches the cable and torqued/sealed it.



I did this now, because it was trivial to ensure that the cable was aligned with the baggage wall pass through. If I waited to do this after installing the top skin, I'd be climbing back in the tail to tweak the alignment.



I installed the baffle in the vertical portion of the front cover (just below where the air vents are in the cover).  I didn't get a picture of it, but it needs to be match drilled and riveted along with a handful of nutplates.



I also installed the fuel selector mounting bracket and cover that ties the bracket and lower cover together.



I was planning on cutting off the angled triangular portion since I'm not using the manual elevator trim.  I noticed however that that would leave a large gap between the fuel selector bracket and the vertical cover.  Instead, I flipped the bracket over and will cut off the triangular flange slightly forward of the bend to cover the gap.



Since the lower portion of the vertical cover has the forward face removed for the fuel pump, I won't use the lower two #19 holes to tie the two pieces together.  This means I can move the lower cover back to eliminate the gap between the lower cover and the spar forward covers.  I started trying to lay out the holes through the floor stiffeners that attach the lower cover, but the aft holes will also attach the fuel pump mounting bracket, so I want to make sure that it position first.



The Andair fuel selector valve intlets can be installed in any cardinal orientation and are held in place with four stainless steel screws.  I used some fuel lube to lubricate the o-rings, and them installed the inlets facing down.



After installing the stainless steel screws, a punch is used to deform the screw into a recess to prevent it from backing out.



I drilled the fuel selector mounting bracket for the fuel selector by first drilling a 1" hole inthe middle.  I purchased a large unibit knockoff from Harbor Freight a few weeks ago to make larger holes like this.  Unfortunately, it is a complete piece of shit and took several minutes to enlarge this hole from 7/8" to 1".  After drilling the large hole, the valve was positioned and the three outer holes are drilled for the mounting screws.



Finally, K1000-08 nutplates can be installed on the valve and the valve can be installed on the mounting bracket.  I spent a little time trying to bend a 3/8" fuel line to connect the fuel selector outlet to the fuel pump, but I don't think I can bend the line according to the plans since the bend radius is tighter than my bender allows.  This probably means that I'll need to install the fuel pump slightly forward of the specified location.



The plans specify that the aft end of the filter be roughly vertically aligned with the fuel selector outlet.  This requires the fuel line to jog backward before turning forward to enter the fuel filter.  The radius on my tubing bender is to large for this to work and still have room to push the fitting back to create the flare on the end.  Instead, I moved the filter and pump forward about two inches and fabricated a line with a simple 90º bend.  I'm hoping the stock Van's fuel pump cover will still fit over the pump.  Otherwise, I'll have to fabricate a custom cover.



I fabricated the mounting brackets as specified on the Andair plans.  I removed a section of the vertical portion of each of the mounting angles since I'll be running quite a bit of wiring through this bay as well.  This is 1/8" thick angle, so it's still far stronger than it needs to be.  I could have probably used 1/16" thick angle, but this is what the plans specify.



Here is the fuel pump screwed into place on the mounting brackets.  I still need to drill the floor stiffeners to the cover, but I needed to get the brackets in place so that I could drill through the angle clips on each end.  I need to order some MK1000-08 nutplates to use on these clips since regular K1000-08 nutplates are too long.



Drilled Forward Cover

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I fabricated a little drilling jig to ensure the holes were a fixed distance off the floor.  After some careful measurements to ensure I'd hit the clips on the ends of the mounting brackets, I drilled the floor stiffeners to the forward cover.



It looks like my measurements were accurate, I hit the center of each of the clips.  I'm waiting on some miniature nutplates from Aircraft Spruce, then these can be riveted permanently.



The forward two holes just go into the cover, so I installed a couple of K1000-08 nutplates there and then reinstalled the cover.



Now that the cover is in its final location, the two upper holes can be match drilled into the firewall recess.



I drilled and countersunk for NAS1097 rivets, but I can't reach these with a squeezer so I'll have to shoot these later.



I got started tonight by filing the edges of the aft canopy decks flush with the side of the fuselage and I finished dimpling all of the holes that attach them to the longerons.



Next, I clecoed the upper forward fuselage structure together.  The left most panel is the instrument panel.  The middle panel is the subpanel, and the firewall is on the right.  There are two large ribs that tie these pieces together as well as a couple of large gusset plates that tie the longerons to the subpanel.



Here is the back side of the instrument panel showing how the rib supports the panel.  Unfortunately, part of this rib will have to be cut away to make room for the SkyView display.



I have been playing with instrument panel layouts in ePanelBuilder, but I was unsure where the centerline of the seat is relative to the panel.  I measured this out and made a couple of marks on the panel.  I then got in the plane and spent a little time toying with layouts.  In this picture, the SkyView display is a little over an inch to the right of the centerline of the pilot's seat, but I think I like it better there rather than directly in front of me since it provides room on the left of the display for a bank of switches and makes the display easier to reach with my right hand.  There is still plenty of room to the right for the radio stack, a Dynon D6 as a backup PFD, and the map box.



I have no idea why I decided to do this tonight, but I installed the fittings for the fuel tank vent lines into the side of the fuselage and torqued them down.  Here is the outside where the line from the fuel tank will attach.



And here is the inside.  A line will attach here and run up to the upper longeron, forward to the firewall and then back down to a fitting in the floor.



I also installed a couple of the same fittings through the firewall for the brake lines.  Here is the forward side of the firewall.  Lines will attach here and then run down the gear legs to the wheels.



Here is the aft side of the firewall.  These fittings face upward since the parking brake valve will be mounted above this point.



Here is roughly where I'm planning on mounting the parking brake valve.  This gives me a convenient point on the rib above to attach the parking brake cable.  I'm going to hold off installing this for a bit to make sure this mounting point doesn't interfere with anything of the front of the firewall.



Here you can see that it's a fairly straight shot from the parking brake to the fittings through the firewall.  I'll fabricate solid aluminum lines to connect these two.



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