5. E-flite Carbon-Z Cub Assembly Log (Updated 10/10/2014)

Update: 7/19/2014 – First impression is that this is a big foam plane, nearly 85 inch wing span and just over 8 lbs. I consider it a large .46 size glow.

Accordingly the box is big as well.

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I purchased the Plug-n-Play version from a local hobby shop which does not include a receiver. This was a mistake. For $20 more, the Bind-n-Fly version includes a Spektrum AR635 6-Channel AS3X Sport Receiver which retails for around $80.

I dismissed getting the Bind-n-Fly because I have a surplus of receivers and I wasn’t interested in the AS3X flight stability technology. So the mistake was that later I learned that the stability can be turned off. $20 for an $80 receiver is obviously a good deal.  (Update 8/8/2014)See my comments about the AR635 AS3X recevier in the Splendor assembly log.

Opening the box finds nothing that you wouldn’t expect from Horizon. Well designed packaging and not one sign of damage.

In case you were wondering what Carbon-Z means?

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Assembly is limited to the these basics; front gear, tail section, motor and receiver. Being a Cub it does require assembling wing struts, but that’s about it.  All servos and linkages are installed and ready to go.

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Don’t forget to use Loctite on the wheel collars.

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The flight control surfaces are pre-attached with CA type hinges, except the rudder.  Since the Cub is made from Z-Foam, which is similar in appearance and function to Elapor and EPO, but without the greasy feel to it, thin CA is used.  I’ve never used CA on foam and found that the CA took over night to harden. You can use CA kicker to accelerate curing, but the factory warns that it can damage the paint.  I may have used too much but I’ve never seen CA take this long before. (Update – I figured out that I have a bad bottle of CA, the long cure time was not related to the foam)

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Part of the struts use pins and clips making assembly and disassembly a breeze at the field.  Mounting the struts to the fuse also uses these fasteners.

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The four motor screws are oversized for the plastic mounting holes requiring a full-sized tool for extra grip and torque. Wire management is bad as there is no room to tuck the wires cleanly away from the spinning motor casing. I slightly twisted the wires and used a wire tie to keep them safe.

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Battery installation is easy with the built-in adjustable mount. However, accessing the battery with non-child size hands ends up deforming the foam around the opening if you’re not very careful.

Morgan RC manufactures a laser cut ply battery cartridge for the Carbon Z Cub. Looks like it can make battery installation and removal a lot easier.

Morgan RC Battery Cartridge
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I used foam shelf liner on both the battery and mount to keep the battery from sliding around.

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I’ve since located the receiver further into the fuse to keep the antenna wire away from the metal pushrod.

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I’m using the Turnigy 6s 3300 45-90c Nano Tech lipo as that was the only option available at the hobby shop.  The Nano Tech version is not necessary, nor the 45+ c rating.  30c is plenty.  I’m getting the regular 30c version as spare packs. Recharging at the field using 12v’s takes way to long for me so I like having extra fully charged packs ready to go.

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Connecting the Turnigy battery to the E-flite ESC requires either using a connector adapter or removing and replacing one of the two different connectors. I opted to use an adapter just for the sake of convenience and for preserving the original configuration for future needs.

I ended up making my own adapter as I could not find any pre-made ones that had a HXT 4mm (red) to an EC3 (blue) size.

I wasn’t able to use my Watts Up Power Analyzer at this time to double-check the amp draw as I did not have connector adapters or extra connectors to make some, so I had to hope for the best.

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I found adapters at Progressive RC.

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One thing that can’t be stressed enough is that whenever you are arming the ESC during setup you remove the prop if the plane is not secured. Never take that chance. Keep in mind that electrics can be more dangerous than a rattle snake. At least with a rattler you get a warning before it strikes.

After binding the receiver and setting the throws to factory recommendations, no mechanical adjustment were needed.

Total assembly time was around 3 hours, taking my time and not rushing it.

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Update: 7/26/2014 – Full assembly at the field took 7 minuets.  Double checked the throws and did a range check.

Taxied to the runway and was ready to go.  Took off with medium power but was squirrely on the black top and went hard right.  I’m sure I just need to figure out what she wants for the next take off and be more authoritive with the rudder.

Performance in the air was okay and I’ve read that an APC 15 x 6 prop makes a big improvement over the stock one.  Only needed two clicks of right aileron to fly hands off straight and level.

Be ready to add some rudder in the turns. The factory recommends mixing rudder with aileron which I did not do for the maiden but I certainly will try this.  I did add 42% down elevator mix for the flaps as the factory recommended, but that is way too much so I didn’t test the flaps.

Landing was okay.  It does slow down nicely without flaps but the ground handling for me with the hard foam wheels on hard black top was a mess and made a bunch of racket. I’m changing out the wheels for softer rubber ones.

A 6 minute flight left 58% charge in the battery, but that was all straight and level flying.  We’ll see what’s left after a nice flight with aerobatics and lots of touch and goes.

All-in-all a nice plane.
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Update: 7/31/2014 – Replaced the stock wheels with a set of Cub wheels from my Aeroworks Super Cub.  The plane balances a bit nose heavy so I was concerned about extra weight but the Aeroworks wheels at 5.9 oz each versus the stock ones at 5.4 oz each shouldn’t make a big difference.

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Update: 8/2/2014 – Second and third flights today were much better.  Ground handeling was much improved with the rubber tires, but still requires quick rudder responses to keep the take offs and touch and goes straight.

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Update: 8/3/2014 – At the field this morning I was able to use my Watt’s Up meter to check the peak Amps and Watts at full throttle.

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With the stock prop 56.32 peak Amp draw, just within the range of the 60Amp ESC.

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With the stock prop 1,332.5 peak Watts.

Using the Amps and Watts we can figure out some performance numbers:

Flight time at full throttle = ~3.54 minutes  (battery capacity mAh divided by amps x 60)

Flight time at half throttle = ~8.61 minutes (I forgot to take a half throttle peak reading so I just halved the full throttle peak so this is an estimate for now)

Watts per pound = 157 (Watts divided by plane weight)

Internal Combustion equivalent= 1.8HP (Watts divided by 746)

Update: 8/16/2014 – Flew today with the Morgan RC Battery Cartridge installed in position number 6.  I was able to move the battery further back to get some weight off of the nose which improved the feel of the plane in the air and on landing.  Found the sweet spot for the flap-elavator mix and enjoyed some slow flying and better touch and goes.

I also swapped out the stock prop for the APC 15 x 6.  The prop required just a small amount of sanding to balance then I ran some numbers on it with the Watt’s Up meter.

With the APC prop 58.99 peak Amp draw.

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With the APC prop 1,395 peak Watts.

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Interesting how close the performance is between these two props but makes sense as I couldn’t detect any real difference in the air. There was one noticeable difference though. When I bench ran the engine at full power with the stock prop there was a significant amount of vibration.  I checked the balance of the prop and it was perfectly balanced from the factory.  When I put the balanced APC prop on the amount of full throttle vibration was hardly noticeable.

I have to assume the stock prop is deforming at high RPMs causing the out of balance vibrations and the APC is not.  I can see that a high performance airplane at max RPM in flight would have better performance with the APC, but with the cub, full throttle flying is not the norm.

Update: 10/5/2014 –  Just ordered the float set – EFL1045016 –  in preparation for a couple of upcoming float fly’s.

Update: 10/10/2014 –  Click here for the float installtion review.

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Comments
  1. J.C. Cone says:

    Thank you for this article and the photos. I just got the CZ Cub and now have 12 flights on it. I have the Morgan Battery tray just need to install it. Haven’t used the flaps yet. A long-time instructor pilot of full-sized planes advised me to use 10 percent flaps for take-off. I painted the battery hatch area with Elmer’s ProBond glue to prevent paint flaking off. It dries crystal clear and actually enhances the colors. Will try the APC 15 X 6 per your suggestion. Question: you said you “found the sweet spot” on the elevator-flap mix. What percent of flap is the “sweet spot”?
    Best Regards
    JC

  2. Phil says:

    Thanks for your review…very helpful. I just bought a new Carbon Z Cub and was wondering about the manufacturer’s recommendation of 42% elevator mix, which sounds ridiculously high to me. What % elevator did you find worked best with full flap deployment,?
    Phil

  3. JUST CURIOUS IF STILL FLY THIS CZC IN ANY MORE? ANY UPDATED THOUGHTS OR SUGGESTIONS? THANKS

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