Chuck and Ryan's Build Tips

[Daveembry]

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.

Attachment 5023

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.

Attachment 5024

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.”

Attachment 5027

Chuck, Thanks for this post. Just finished mounting the cowl and your tip here about using the blue, 1/4" tape worked MUCH better than trying to scribe the line and cutting. I did it this way using the dremel cut-off blade as well and it came out about as much of a perfect fit as you could get. Thanks again!

[Daveembry]

I am suffering from empty garage syndrome.

The Cub left the nest and headed to the hanger this week.

Attachment 5242

Chuck, getting ready to haul mine over to the hangar and be an empty nester myself. Looking at your photo, looks like that left main wheel is off the trailer but not sure by the photo. Did you put a board or something over there to hold it up or is it just an illusion? The trailer I have is 87" wide and no side rails. With the 29" tires, it's about 93" outside to outside, so trying to see how to do it.

Also, no problems with the rudder with the gust lock on? I see you removed the elevators (or haven't installed them yet). Reason for not putting them on (trailer too short; afraid of wind with the tail facing forward, etc??).

I have a pretty long 20 mile haul but all nice, wide backroads.

THanks

[TroyBranch]

FWIW I towed mine forward. It had to go down a high way so I did not like all that load on the tail. I had the elevators on so that was the other reason. I just call a tow truck tilt deck.


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[ceslaw]

Chuck, getting ready to haul mine over to the hangar and be an empty nester myself. Looking at your photo, looks like that left main wheel is off the trailer but not sure by the photo. Did you put a board or something over there to hold it up or is it just an illusion? The trailer I have is 87" wide and no side rails. With the 29" tires, it's about 93" outside to outside, so trying to see how to do it.

Also, no problems with the rudder with the gust lock on? I see you removed the elevators (or haven't installed them yet). Reason for not putting them on (trailer too short; afraid of wind with the tail facing forward, etc??).

I have a pretty long 20 mile haul but all nice, wide backroads.

THanks

It is probably an illusion. The trailer was just wide enough to get both wheels on and they were very tightly secured.

The elevators were removed so we could get it out the garage door. There was about a quarter inch clearance with the stabilizers. One less thing to be flopping in the wind.

The lock on the rudder worked very well. Make sure it is well padded and don't overtighten.

I would have preferred to go down the road forward, but that did not work with the trailer we were using.

We kept our speed well under 50 MPH en route.

Wings transported on the holders we made, which were tied tightly to the trailer. The wings were secured less aggressively on the holders to avoid damaging them

[ceslaw]

Chuck, Thanks for this post. Just finished mounting the cowl and your tip here about using the blue, 1/4" tape worked MUCH better than trying to scribe the line and cutting. I did it this way using the dremel cut-off blade as well and it came out about as much of a perfect fit as you could get. Thanks again!

Glad that worked. I picked up that trick fitting the fiberglass panels on the GT40.

[Daveembry]

FWIW I towed mine forward. It had to go down a high way so I did not like all that load on the tail. I had the elevators on so that was the other reason. I just call a tow truck tilt deck.


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Troy, Yes, I would much rather tow it forward as well and probably will try to figure out a way to do that since I do have a good distance to go. The trailer I have available now that is wide enough, has the tire fenders in the way that are more narrow than the trailer and I would have to ramp the mains up over the fenders. In Chucks trailer, you can see the tires/fenders on the trailer and on the outside of the bed and the one I have actually is as wide as the outsides of the tires, making it plenty wide for the plane but the fenders/trailer tires are more narrow. To get it on the forward part of the trailer I will have to get the mains up past those fenders and that has me a bit apprehensive. Thought about just putting a couple of atv ramps on the trailer to go over the fenders.

[Daveembry]

FWIW I towed mine forward. It had to go down a high way so I did not like all that load on the tail. I had the elevators on so that was the other reason. I just call a tow truck tilt deck.


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How did you guys physically get it up the trailer? Just push/pull it or did you need a winch? I'm guessing the width with elevators on is close to 10' so I guess you just watch out for sign posts and mailboxes huh.

[ceslaw]

How did you guys physically get it up the trailer? Just push/pull it or did you need a winch? I'm guessing the width with elevators on is close to 10' so I guess you just watch out for sign posts and mailboxes huh.

Two seasoned citizens and a 50 year old young whipper snapper had no difficulty manually coaxing it onto the trailer. The plane sans wings weighs in around 800 pounds. With decent ramps loading it should not be hard.

[ceslaw]

VSI


When the plane was originally built, we included a pair of steam gauges in the spot where the autopilot control would normally go: an air speed indicator and altimeter. The air speed indicator is very useful, but the altimeter not so much. It is a single needle gauge up to 20,000 feet, so it is at best an approximation of altitude. We rarely looked at it, since the G3X altimeter ribbon was so much easier to read.

The Garmin G3X has a small VSI scale next to the right altitude ribbon. It is tiny and hard to see. In a plane that climbs like the Carbon Cub, something more appropriate was needed.

We swapped out the altimeter for a VSI. (UMA 2 ¼”). It works great and captures the character of the plane better than any other gauge. First flight with this new gauge we climbed out over 1500 FPM on a warm, humid, evening. It is so much easier to see at a glance than the VSI image on the G3X.

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[ceslaw]

On the Level.


A Carbon Cub EX2 is under way so I will start posting the occasional tip resurrecting my dormant build blog from the EX1. So much has been posted in the five years since my EX1 started flying that not much remains to be said, so I won’t say much. Just the finer details.

The first pages of the wing manual make clear the importance of locating the saw horses the correct distance apart and assuring they are level, both longitudinally and transversely. The real reason for this precision is to make sure the washout is correct. Here is a little tip for anal builders, like me.

Just before the drag wires are trammeled with the fish scale, use the digital level to confirm that the most inboard and most outboard drag tubes match before setting the aft rear corner on the one-inch block. They don’t have to be at zero degrees, just the same. A thin shim between the inboard spars and the saw horse may be needed. Then lift the outboard end and place it back on the one-inch block. You now have precisely one inch of wash out over the distance of 151 inches.

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I needed to add thin cardboard shims to get the ends within a tenth of a degree on the left wing. The right wing was within that tolerance without any shims.

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When the set up was done the difference in angle between the inboard and outboard drag tubes was 1.9 degrees. Makes me wonder if the design calls for 2 degrees of washout from wing root to wing tip.