Back From Oshkosh

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I got back from Oshkosh late last night.  I had two main goals for my trip to Oshkosh: decide on an engine and decide on an EFIS.

Engine: I had heard good things about the IO-375 from AeroSport Power.  Fundamentally, it is a parallel valve IO-360 with a redesigned crank that simultaneously lowers compression ratio (8:1) while moving the peak pressure to a point in the crank’s rotation that has more mechanical advantage.  The end result is an engine that weighs exactly the same as the parallel valve IO-360 but makes 195 hp.  I spoke at length with Bart LaLonde and am now convinced that this is the engine I’ll go with.

EFIS: I have been really impressed with the preliminary info about the Dynon SkyView system, but I wanted to take a close look at Dynon, Advanced Flight Systems, and Grand Rapids.  The Advanced and Grand Rapids systems are available now and look very nice, but I don’t need my avionics for a while, so that isn’t a big factor for me.  The Dynon system is not yet shipping, but it looks like it will be even nicer than Advanced or Grand Rapids by the time I need to buy anything.  I really like the modular aspect to the system which not only makes it easier to install and upgrade, it makes it easier to extend in the future.  Given that it still has a ways to go before it has all of the promised functionality, I want to wait before making a final decision, but at this point, I’m about 95% sure I will go with the Dynon SkyView system.

Fabricated Autopilot Roll Servo Wiring Harness

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My order from B&C Specialty arrived yesterday with the wiring components I need to fabricate the connection between the autopilot roll servo and the wiring harness.  First up is to crimp the sockets onto the wires on the wiring harness.  It’s hard to tell from this picture, but these wires are small.  The wires are a mix of 20 and 22 gauge, and these sockets are about 1/16″ in diameter.

Next up is to crimp the corresponding pins onto the wires on the roll servo.  Afterward, I put these wires in some heat shrink tubing to keep them tidy.

Here are the wires from the servo inserted into the D-Sub 9 pin male connector body.  The goopy stuff on the wires in E6000 adhesive.  Basically, this forms a strain relief that prevents individual wires from flexing at the connector.

Here is the corresponding female connector on the wiring harness.

Purchased Teflon/Tefzel Wire Stripper Blade

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My Ideal StripMaster wire strippers came with the L-4421 knife blade.  This is fine for typical PVC insulation that most things are wired with, but it isn’t ideal for the tefzel insulated wire used in aircraft; the sharp edge can nick the wire.

The correct blades for teflon/tefzel are L-5211, but these are expensive (~$100).  I lucked out and found a set on eBay for $10 though so I picked them up.

Forward Fuselage Fabrication and Panel Layout

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I got an order from Van’s today that included the fuel pump cover.  This normally sits higher than this because the forward face of this is vertical and the angled face is more steeply sloped upward.  This provides room for the much larger Airflow Performance fuel pump/filter/check valve assembly.  This configuration won’t work for me because I had to move the fuel pump forward almost 2″ to fit the fuel line between the fuel selector and the fuel filter.  This puts the pump outlet far enough forward that there is no room to allow the fuel line on the outlet side room to turn down and drop under the cover.

I reduced the angle of the bends in the cover, which simultaneously drops the height of the cover down as well as pushes the front end forward enough to make room for the fuel line..  I’ll have to fabricate new side covers from some scrap 0.020″ stock, but that’s pretty trivial.

I started fabricating some of the small components for the forward fuselage out of 0.063″ angle stock, but it’s late and this was making a racket.

Instead, I spent a little more time playing with panel layouts in the plane.  The cockpit is small enough that I can reach every part of the instrument panel from the pilots seat without leaning over (I have really long arms though).  This also means that it’s pretty easy to see everything, regardless of where it is on the panel.  I’ve been planning on going with a single 10″ screen Dynon SkyView system, but lately I’ve been considering trying to fit a dual 10″ screen into the panel.  Even with the 10″ screen, using just one screen for PFD, Map, and engine monitoring can get kind of cramped.  I think dual screens would force me to remove the Dynon D6 that I was planning to use as a backup PFD though.  Although I could add a second ADAHRS box, I’d still be relying on a single overall system which worries me a little bit.

Installed Autopilot Pitch Servo

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I dug out the autopilot pitch mounting kit and installed the servo into the mounting bracket.  It took a couple of tries, but I got it safety wired.

I then installed the elevator bellcrank and hooked up the pushrod.

The servo comes with a limiting bracket to prevent the arm from going over center and binding the controls.  I installed it so that the arm can go about 80º to either side of the point where the arm is 90º to the pushrod.  In practice, the elevator will hit the control stop long before the servo arm hits the limiting bracket.  Update: This bracket is installed incorrectly.  Please refer to the Dynon installation instructions for the correct orientation.

Finished Seat Pans, Fired Up Dynon SkyView

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I finished installing the aft seat pans.  These aren’t primed like the baggage floors because these will get painted with a paint that matches the carpet color since part of these may be seen around the edges of the carpet.

I got my Dynon SkyView 10″ screen and associated extras (ADAHRS, backup battery, EMS and probes, GPS antenna, etc.).  I hooked up the appropriate power and ground pins in the D-Sub 37 pin connector as well as the ADAHRS and backup battery, and powered it on.  After a quick configuration, I had the attitude display up and running.  There is no synthetic vision yet because the GPS isn’t hooked up so it doesn’t have a position fix, but it was cool to play around with moving the ADAHRS and watching the display change.  The screen refresh rate is quite high, so the movement is very fluid.

Firewall Forward Wiring

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I finished the battery positive cable.  There will be a couple of adel clamps securing this to the adjacent engine mount tube to prevent the terminals from carrying the full weight of the cable.

I also fabricated the engine ground strap.  I used an empty hole near the oil filler neck which required removing all of the paint on the aft side of the boss.

Here is how the cable routes up to the grounding strap.  You can also see the battery negative cable here.  I can still easily remove the battery without having to loosen any cables.

I also put the fitting on one end of the starter cable.  I left the starter cable a little long since I’m not 100% sure of the routing right now.  It needs to pass through the same area as the mixture cable and bellcrank, so I want to have that in place before finalizing the routing.  You can also see in this shot that I added a washer under the fuel fitting.

I moved the 45º fitting up to the top port in the pressure transducer manifold and installed a 90º fitting in the bottom one for the fuel pressure hose.  I also installed a couple of polyethylene hose fittings in the top port.  One will route manifold pressure to the Dynon MAP sensor just to the left and the other will route manifold pressure to the Lightspeed electronic ignition.

I also spent a little more time playing with the locations of the various boxes that will mount forward of the subpanel and I think I came up with a layout that I like.  Here is where the Dynon EMS box will mount.  I separated the sensor wires from the 37 pin connector into one bundle that needs to penetrate the firewall and one that doesn’t.

Here is where I’m planning on mounting the Lightspeed ignition box.  This provides convenient routing of the primary ignition wires which will run alongside the battery and main bus power lines.

And here is where I’m thinking of installing the voltage regulator.  I can still easily reach the voltage adjustment screw in this position.  The only disadvantage is that I need to drill a few more holes in the firewall.

Worked on Canopy Latch and Engine Start Button

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I stopped by the hardware store this morning and picked up some 7/32″ and 9/32″ brass tubing.  I then drill out the latch pieces so that these are a press fit into the holes.  This will allow the brass tubing to rotate around the bolt.  This totally fixed the sloppy fit and the bolts are a slip fit through the holes now.  I’m not going to install these permanently in the holes yet since I’m planning on having the latch components hard anodized.

I also drilled the latch attach angles to the latch components.  Here is the latch temporarily assembled so that I can check the clearances and movement.

On the other side, you can see how the latch sits proud of the attach angles.  This is because the attach angles will sit flush with the inside of the skin, but the latch components should be flush with the outside of the skin.  The skin is 0.032″, but I positioned these currently 0.036″ proud of the angles.  After I get them back from the anodizers, I’ll file the outside faces flush with the side of the plane since they’ll be painted the same color as the exterior.

I’ve temporarily clamped a piece of scrap material across the outside face to simulate the skin since the skin acts as a stop for the forward catch.

To open the latch, you push forward on the forward knob until the aft part is released.

Once the latch is released, the aft part pops back.

It can then be pulled aft to release the canopy.

Finally, I laid out the cutout for the side skin.  It’s late, and I want to do this when I’m fresh, so I’ll start this tomorrow.

I wasn’t completely tired, so I wanted to figure out how the engine start switch will be wired.  I don’t think I’ve mentioned it before, but I’m using the engine start switch from a Honda S2000.  It has an integral light, but it’s really dim and can’t be controlled separately from power to the switch.

To solve this, I disassembled the switch, cut the traces to the light and wired them to the two unused pins on the connector.  If I end up using the Vertical Power VP-X, it can turn on the light when the start button is enabled.  I think I’m going to have to use a relay between this switch and the starter relay since I’ve heard the starter relay pulls about 4 amps and I don’t think this switch can handle that kind of current.  I need to confirm this though.

Fabricated ADAHRS Mount

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I decided to take a break from the canopy and fabricate the ADAHRS mount for the Dynon SkyView ADAHRS box.  I looked at several builder’s sites about how other people have done this and settled on a U shaped piece hanging between the center rib and left stringer.  I decided to add some bends along the edges though to stiffen the structure.  It’s approximately level in both axes right now, but I need to fine tune it slightly before drilling the holes though the rib and stringer.

I made the box deep enough that I could put two ADAHRS boxes (stacked vertically) in here if I decide to do that.

Dynon SkyView Supports the Vertical Power VP-X!

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Dynon and Vertical Power this morning announced that the SkyView system will be supporting the VP-X.  After seeing the VP-X at Oshkosh last year, I decided to defer working on the electrical system as long as possible in the hopes that this will happen.  Thanks guys; this combination is going to rock!

Here’s the announcement from Dynon:

http://www.dynonavionics.com/docs/news_VPX_announcement.html

It’s a little disappointing that they’re charging an additional $275 for this given that they’ll almost certainly sell more SkyView systems as a result and because every other avionics supplier is including it for free.  Dynon products are already priced much more aggressively than their competitors though, so I’m not going to complain too loudly.

Here’s an overview of the VP-X:

http://verticalpower.com/vp-x/

After working through the load planning, I’ll be going with the VP-X Pro.  Using the VP-X should not only simplify wiring, it should provide substantial new features to the electrical system as well as advanced fault detection.

Now, if Garmin would just announce a replacement for the GNS-430…