Back from Thanksgiving with family at Bear Ass Cove on Newfound Lake, New Hampshire and guess what UPS delivered? That’s right – the avionics harness!
I’m almost ready to install the harness – just a couple of empennage things left to finish – but I couldn’t resist stretching it out. This is, essentially, the Mighty RV’s nervous system and having it fabricated by the neurosurgeons at Approach Fast Stack is saving me a *ton* of build time. Cool!
I’m awaiting delivery of the avionics harness from Approach Fast Stack so I decided to tackle a task I’ve been avoiding for more than 13 years – fitting fiberglass tips to the horizontal stabilizer, elevators, vertical stabilizer and rudder. I’ve said before that I hate working with fiberglass and that’s still the case.
Van’s ships the elevator tips with no front end and recommends fairing over the counterweight with an epoxy/flox fill, essentially making it non removable. I decided to add a thin fiberglass layer over but not attached to the counterweight so that I can remove the tip later on if necessary.
Tip prep was simply sanding down the front surfaces to give the layup something to bond do.
I laid up 3-4 layers of 9 oz BID cloth over the counterweights and front of the tip. Before doing that I covered the elevator and counterweight with clear packing tape as a mold release.
The layup initially looked too thick but when I sanded it down to match the elevator and HS tip there wasn’t much left – but there really doesn’t need to be.
Here’s the inside of the tip after removal..it conformed pretty nicely but I had some voids in the cloth that required some additional epoxy to fill.
After sanding and before priming…looks good!
The HS tips come without a back end and there’s no requirement to add one but they look better and more “finished” if they’re closed – so that’s what I did, using the foam technique in Section 5 of the instructions and and a sheet of pink foam insulation from the aircraft construction department at Home Depot.
The same foam closeout technique was used on the VS tip…already done in the pic below.
The rudder upper fairing was a really poor fit, a common complaint with previous versions of fiberglass parts shipped by Van’s. I had to build up the front end with balsa and fiberglass, and apply epoxy and microbaloons to fill gaps on either side.
Surprisingly, the rudder lower end cap fit pretty well when trimmed to the scribe marks applied by Van’s. I decided to make it removable by adding #6 platenuts to fairing attach points on the rudder.
The lower end cap looks good now, but pop-riveting the nav/strobe light attach plate caused the fairing to crack (shit!) so I had to mix up some epoxy and flox for a fix.
Here are all the emp tips sealed and primed with K36 primer to protect them until time for paint.
Finally getting a lot of little cleanup tasks done while the avionics harness is percolating at Approach FastStack.
First, I installed this…
First person to guess what it is gets a ThermosWorks sticker or a free beer at Oshkosh 2019.
Second, I dug out the cockpit lights from Oplite and fabricated a small bracket to mount them on the roll bar support.
These lights are extremely well-made by my friend and fellow RV builder Rich Mileika. In addition to Oplite, Rich owns and operates Machine, Inc, a precision machining company in the greater Boston area. If you need quality cockpit lighting, try Oplite…you’ll like ’em.
And lastly, I replaced the stock Van’s flap motor with an upgraded version made by Pat Hatch at PH Aviation Services.
This motor has several advantages over the stock unit. The motor and jackscrew are separate so grease can’t migrate into the motor windings, a common problem with the Vans motor. It also has limit switches to stop the motor at full extension on either end, and also has a position sensor to report flap position to whatever device needs it.
The only downside is that the flap support bracket must be modified to accommodate the new motor. Rather than trying to rework the existing bracket, I bought new parts from Vans and started from scratch…only took a couple of hours, and Pat’s motor will save some wiring work later on.
I think it’s time to start mounting stuff in the panel. Being an electronics/avionics geek, I’ve waited for this for a long, long time.
The G3x GSU 25 ADAHRS is mounted on the subpanel behind the PFD/MFD – makes plumbing the pitot-static lines to the GSU and G5 a little easier. It was hard to get in there with a ruler to lay out hole positions so I made a drill template out of thin Al.
One minor hiccup…the ignition switch locking tab isn’t clocked correctly, causing interference between the switch body and panel support rib. I’ll probably have to grind off the tab and rivet on a new one at the right orientation. The switch label will cover the rivets nicely.
More fun with avionics…finally figured out where to place the IBBS avionics backup battery, it’ll go behind the subpanel. The battery has a dsub connector on its right side, it’s placed so the connector will go though the subpanel lightening hole.
…is getting brighter – it’s time to start installing and wiring avionics. I’ve been plotting and planning how to mount the Garmin G3x Touch system, radios and transponders and I’ve settled on building a tray which will hold all the remote-mounted LRUs, Comm 2 and transponder.
Here’s a cardboard mockup.
The GAD 27 and GAD 29 are on the right side. Most of the airframe power interfaces will be through the right firewall passthrough so having these boxes on the right should make wiring a little more straightforward.
We don’t plan on painting the RV for awhile, so I called Jonathan McCormick at Evoke Aviation – our painter of choice – and asked for his recommendation about how to protect the cowl ’til time for paint. His recommendation was K36 high-build epoxy primer…so that’s what we used.
The oil filler door looks good, although I’ll likely end up sanding down the sides a little to increase the gap for painting later on.
Following the instructions for UV SmoothPrime, I’ve laid down several coats and each one means a lot of sanding. Fortunately, it sands pretty easily and seems to do a good job filling any voids or pinholes left after the coats of micro and epoxy I applied.
It’s a little splotchy in some spots, but it’s good enough for the high-build epoxy that’ll cover everything until paint.