Chuck and Ryan's Build Tips

[3phase]

Thanks for the tip. I think I ripped 3 grips before I got one on successfully. The rear stick is simple because there is no PTT switch. Next time I'll give your technique a try.

[ceslaw]

Boot Cowl, Anti Chafe

There was this piece of plastic, 12” x 3”, part number SC71010-001, described as “anti-chafe”. It was referenced in a drawing, but frankly its function did not jump out at me. After the boot cowl was set in place it made sense: it protects the switches.

A pattern was made to assure the minimal amount of plastic was cut away to clear the two frame tubes. Less obvious, however, is the notch that needs to be cut to clear the rib on the underside of the top of the boot cowl. It is off center about a half inch. We cut a half inch wide notch, off center a half inch, to make sure there would be no clearance issues.

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Installing it with the boot cowl in place was a challenge. Once the location of the cuts was confirmed the cowl could have been moved forward which would have simplified the job.

That pattern also came in handy when trimming the black vinyl to clear the tubes and boot cowl rib. The width of the vinyl was trimmed to match the depth of the anti-chafe strip: approximately three inches


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I was amazed at how everything lined up. The openings around the frame tubes are exactly centered in the openings. Kudo’s to Cub Crafters for the precision of the design and manufacture of these parts, especially on something with as many large and small parts as the boot cowl.

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[ceslaw]

Wiring, Throttle PTT

We added a PTT switch to the throttle knob. (Ryan made a batch of the knobs a while back. We decided to use the Delrin knobs). Two strand shielded wire (Aircraft Spruce 11-05650) was connected to the PTT connection under the seat. The wire was routed up the left side with the wire harness to the area behind the throttle controls. A grommet was placed where the wire passed through the frame and it was nylon tied in place.

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A two pin Molex plug was used so that the wire could be easily connected or disconnected when the interior panel was set in place or removed. The wire was nylon wire tied in place so that the plug was 10.5” aft of the forward vertical brace with the plug facing forward. This dimension is intended to assure that the wire attached to the throttle lever will not interfere with the throttle when moved. The plug needs to be secure to make sure the wires do not slip into the throttle mechanism.

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The PTT switch (Aircraft Spruce, P/N 11-03909) was wired with 22 G wire (we used the two conductors from the same shielded cable, without the shield. The shield made it too stiff). A matching Molex connector was connected to the opposite end of the 11” wire.

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A hole was drilled about an eighth inch from the aft edge of the throttle lever, carefully locating it so that it would be just above the opening in the carbon fiber panel when the throttle is at its limits of travel. A thin piece of wire was used to hold it in place. A short length of heat shrink was used to cover the wire.

Spiral wrap, 3/16”, Cub Crafter RM1004-002, was used to cover the wire from the plug to just where the lever extends above the carbon fiber panel.

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The rear passenger will have a matching throttle without the PTT.

Ryan plans to mill additional throttle knobs in the near future, both with and without the hole for the PTT button if anyone is interested.

[Cubrath]

Nice install!

[ceslaw]

Interior panels

The manual describes double sided tape to hold the interior panels in place. Removing the panels for servicing could be a problem. So we checked with Mitch and learned that Velcro is now being used at the factory where the double sided tape had been used.

Long ago before the fuselage was covered we pre fitted the interior panels and drilled the holes for the plastic clips to reduce the risk of damaging the fabric if done after the place was covered. At that time the location of the frame members was marked on the back of the interior panels with a silver Sharpie so we would have a reference for locating the Velcro.

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Industrial strength Velcro from Lowes came in 4’ x 2” length. It was cut lengthwise into two ¾” and one ½” strip. That proved to be just enough to do the job with only a few scraps left.

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The Velcro plastic “hook” was placed on the fuselage and the cloth “loop” was placed on the panels. The surfaces were wiped down with alcohol and then with adhesive promoter from the local NAPA store.

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To make sure everything is lined up before the “hook” and “loop” come together a length of poster board was placed over the Velcro on the left sill. Masking tape was placed over the Velcro on the vertical frame members with the ends extended. Once the panel was in place the poster board and masking tape were pulled out and the Velcro pushed tight.

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[c130jake]

I did the velcro, glad I did. I had to take the front right panel off twice.... (I will leave it off until I know the ignition/engine/backup battery checks out). It will also make checking the throttle linkage and fuel selector in the future a non event.

Jake

Sent from my SM-G920V using Tapatalk

[ceslaw]

Jake

When is your first flight? You must be close!

I was a bit skeptical of the velcro initially, but it really holds tight. Agree it is a better option that double sided tape.

Chuck

[c130jake]

I thought I would fly last fall. This spring hopefully. Waiting for warmer weather before I tackle the windscreen. The last major things are the engine cowl (the videos made me a bit nervous), hang the flaps and ailerons, the Windscreen, tank lids and seal up the wing roots.

I sent in my registration to the FAA two weeks ago. When that comes back, I will talk to the DAR again and come up with a plan for the timing of the inspection, first flight and the rest of the paperwork.

I have vacation in April and May so keep your fingers crossed.

Jake


Sent from my iPad using Tapatalk

[ceslaw]

Cowl

Reading the manual and viewing the video more than once, I was expecting the cowl installation to be a time consuming difficult task. It turned out to be straight forward and was completed in three afternoon sessions.
The first session was fitting the top and bottom halves, the bottom filter cover, and the oil access door. Cub Crafters had pre trimmed all these pieces so there was only minimal trimming required, contrary to the description in the manual and video. Nonetheless a long sanding block with 180 and 320 grit paper does come in handy.

Next the nut plates to join the top and bottom halves and the bottom filter cover were installed. We made our own drilling template by using a Cleco and just the “plate” part of a nut plate. Set it in place, drill the rivet holes with a 12” long bit (to clear the Cleco), and everything lines up perfectly.

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The second session was fitting the assembled cowl to the boot cowl. Per the video the initial trimming was done with a tin snips. The opening around the flywheel was already trimmed to the final dimensions by Cub Crafters, so assuring it was centered was straightforward. Once the trim was close, with less than 1/8” variations where the cowl and boot cowl meet, quarter inch blue vinyl tape was placed on the cowl, following the edge of the boot cowl exactly. Then half inch blue masking tape was placed on the cowl side of this blue tape and the blue tape was removed. The edge of the masking tape defined the cut line. A Dremel tool was used for the final cut. This produced a precise cut line that required virtually no sanding to produce a fit with no gaps. We ended up with exactly a quarter inch between the back of the spinner plate and the front of the cowl.

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The third session was placing the nut plates on the boot cowl. One little tip: locate the nut plate that is at the top and bottom cowl seam to line up with the horizontal line of screws that hold the top and bottom together. This may require that the spacing of the boot cowl screws specified in the manual by changed by a slight amount.

The point where the top and bottom halves of the cowl overlap the flange on the boot cowl is a bit awkward due to the thickness of two layers of carbon fiber. We sanded that area down to near index card thickness at the aft edge to assure a smoother transition.

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The end result was a tight fit with no ‘bulge.”

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[ceslaw]

Coils

Here are some thoughts on wiring the four coils.

Of course the four cables were marked before the boot cowl was installed; Left and Right, A and B, respectively. If not, good luck tracing them down after the boot cowl and engine are in place.

The shield (actually there are two layers of shield) is the negative connection. Here is how we separated it from the center conductor and made the connections.

First, 2 ½” of insulation was removed. I am partial to using an X-Acto knife rather than a wire stripper because I have better luck not nicking the shield underneath. I cut most of the way through longitudinally then pull the cover apart along the cut line. Then carefully cut cross wise to remove the cover. (If I were doing it again removing 3” of the insulation would be better).

Second, the exposed wire is bent sharply just beyond the insulation cover. A pointed instrument is used to gently push the strands of the shield apart, after which the insulated conductor is pulled through the opening. The shield is not cut.

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Third, the shield is massaged back into shape and a length of heat shrink slid over the shield.

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Fourth, a larger diameter 1 ½ length of heat shrink is slid over to hold it all in place. A half inch of insulation is removed from the center conductor.

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Fifth, the blue connector is crimped on the center insulator and the yellow connector is crimped on the shield. No solder! A short length of 3/16”spiral wrap is placed on the exposed center conductor.

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Finally the wires are plugged to the coils, careful to make sure the center conductor goes to the marked positive tab.

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