Modifying / Upgrading the Carbon Z Cub - RC Groups
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Mar 02, 2014, 08:41 PM
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Modifying / Upgrading the Carbon Z Cub

I thought I would start a thread in my blog for modifying the Carbon Z Cub. The Carbon Z Cub is produced by E Flite and its design team was lead by Quique Somenzini. He left Horizon Hobbies at the end of October 2013. I believe this was the last plane he designed for Horizon Hobbies

Below is from his Wikepedia page:
Quique Somenzini is a professional radio controlled aircraft pilot and designer, owner of model manufacturer QuiQue's Aircraft Company and the 2007 FAI world champion.

A native of Rio Cuarto, Argentina, Somenzini has the distinction of being the youngest competitor in the history of the FAI championships, flying in competition in 1979 at the age of twelve. His father, Mario, is a former champion as well and introduced Somenzini to the hobby of model aircraft flight at the age of nine.

The Carbon Z Cub is the largest production foam airplane. It is a 20% scale RC aircraft.

Product Description

Key Features
  • Easy-to-complete final assembly
  • Quique Somenzini design and attention to details
  • Exceptionally strong, easy to repair, Carbon-Z® construction
  • 5-channel control including functional flaps
  • E-flite® 60-Amp Pro Switch-Mode BEC Brushless ESC included
  • Digital servo control including operational flaps installed
  • Pre-hinged control surfaces with control links installed
  • Plug-in wings and stabilizers
  • High-grade socket-head hardware use throughout
  • Hatch covers provide easy access and a wide range of battery options
  • Included 3 meter sailplane aerotow mechanism requires just a single servo—sold separately
  • The optional camera mount (EFL1045023) is ideal for aerial photographers—sold separately
  • Floatplane ready when used with the Carbon-Z Cub Float Set (EFL1045016)—sold separately
Needed To Complete

- 6+ channel DSM2/DSMX programmable transmitter
- 22.V 6S 3200mAh LiPo flight battery
- Charger for flight battery
Optional Accessories:
- Float set (EFL1045016)
- Camera mount (1045023)
- Tow release sevo (EFLR7155)

Here is well done video by JT Graham of RCgroups where most of the modifications listed in this thread were implemented. Enjoy the video. It is well done.

RCGroups Video Podcast No. 4 - Carbon Z Cub Mods (23 min 23 sec)
Last edited by Prof100; Aug 19, 2014 at 09:06 PM.
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Mar 02, 2014, 08:41 PM
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Before specifics some background information on RC brushless motors
Read the below post by Lucien regarding Scorpion motors and how to protect for a motor burning up. The premise is the quality of a motor can be no better than the quality of the magnets:


Want more power? An Eflite Power 60 470 kv will drop in with some drilling of the back of the stock motor mount to clear the retaining collar. This motor is rated at 1800 watts or 2.41 horsepower which is about 600 watts more than the stock motor's 1200 watts or 1.6 hp.

There is a tradeoff in that you have to use a larger battery (5000 mah 6s) to get the best out of it. Even with a 5000 mah pack the flight time can be reduced to 6 minutes if you use the biggest recommended prop and fly it vigorously.

The collet needs to be locked down with enough clearance to avoid hitting the cowl. Or some washers under the mount can be used as well as an alternative to provide adequate cowl to prop clearance.

Street Price is $109. Higher than many that come from RC stores on the web but less than Scorpion Motors. Scorpion Motors use higher cost magnets that withstand nearly 400 degrees F.

Prop recommendation: 15 x 8 - 17 x 7 electric propeller. A 16x8 is the best prop overall to maximize performance with reasonable run time.

The CZC BL50 size motor is the same as the Splendor and it gets pretty toasty if the Cub is flown hard on the stock 15 x 5.5 prop. One measurement post flight by a member with simple IR temperature gage was about 160F a minute after landing. Be wary of flying with a higher pitch prop (i.e., greater that 15x5.5) may overheat the motor and lose a magnet.

As a sidebar, I write this in the winter of 2013-14 and the 84" of snow in my part of the country has grounded me since Nov. 15th has prevented additional testing. Below is the Power 60 installation in my plane that has aCastle Talon 90 installed.

Step 1 is to desolder the stock male bullet connector and solder on the 5.5 mm Castle male connectors to fit the Talon 90. No surpises here. The key is to use a proper welding station to transfer sufficient heat to plugs and wire so th solder flows. Found something odd. The smaller BL50 uses 12 gage wire and the Power 60 uses 14 gage. Finish up with heat shrink.

Step 2 was to modify the stock BL50 mount by opening up the center hole so it can accept the larger collet on the P60. Removing it from the BL50 requires using a 3 mm allen wrench. By the way, you need to use the stock BL50 mount because it mates with the fuselage mounting holes. The P60 mounting holes are too big for the fuselage. You can drill it out using a 9/16" drill if you have vise to hold it and a drill press preferably. I have both but they are in my snow bound shop which is still in 82 inches of snow that have fallen this year. So, I opted to open up the center hole with my Dremel and a Carbide bit. It took about 5 minutes to size and debur the opening. Once ready installed the mount using the original hex head screws and blue Loctite.

A final step because the overall length of the P60 is just a little less than BL50 is to add some washer to space the motor forward to prevent the prop and spinner for bottoming out on the cowl. This does NOT have to be done because The prop collet can be clamped proud of the cowl, the washers just make the prop and spinner installation easier.

Step 3 was to fit a prop. I chose the APC 17x7 E prop (aerobat recommendation) for starters but it pulled too many amps so I found that the 16x8 is the best all around prop on this plane (thanks SQ4MNand Sideslip). A Great Planes stepped prop reamer opened up the prop mounting hole to fit. The PITA was relieving the back side about 1.5 mm deep to clear the step on the collet. If you used the non scale but effective collet from Headsuprc the prop is a simple pop it on and tighten the spinner.

Step 4 Adapt the Eflite aluminum spinner to accept the larger 17x7 APC E prop. It required a cutting wheel and carbide bit to open up the slot. No big deal, just a handcrafting task. Another option is a simple $4, 6 mm collet available from Not scale but it works effectively and requires no special hand fitting.

Step 5 -- Mount motor to firewall. Please note the use of the BL50 mount is needed to fit the CZ Cub. However, the Power 60 is wider and the screws cannot be installed straight in unless you cut in some reliefs in the motor base with a grinder. I chose to simply thread them in half way before attempting mounting. A standard 3/32" hex head driver still works (just barely). If the P60 was any wider it would require a ball driver. Below is a picture of the motor screw interference with motor base.

Mounting the motor with the screws pushed through the mount takes a little patience to make sure the mount is secured to firewall by going from screw to screw alternating a couple of turns on each screw until snugged down firmly.

The clearance between the backing plate cowl is sufficient with the washers added to back of the motor mount. Mount the balanced prop, install the spinner and go fly.
Last edited by Prof100; Jul 18, 2014 at 10:21 PM.
Mar 02, 2014, 08:42 PM
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Castle Talon 90 is a logical upgrade with its "super SBEC" (9 amp continuous and 20 burst). Installation is simple, you only have to open up the ESC pocket to assure adequate airflow and width to fit the 90 amp Talon. Remember even this super SBEC is being asked to step down the 6S pack to receiver and servo voltage. Heat is generated which has to be properly managed by providing adequate cooling. You also have to desolder the male plugs on the motor and install the supplied Castle 5.5 mm male plugs. Price is $65 if well shopped.
Last edited by Prof100; Aug 19, 2014 at 01:55 PM.
Mar 02, 2014, 08:42 PM
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Powering the Receiver and Servos

A reliable high amp external BEC is the easiest upgrade if nervous about an internal BEC. Or see the ESC upgrade with 9 amp continuous Talon 90. Or, power it with standard, below 6 volt receiver pack just make sure it can deliver the current with the stabilization system. If you use A123 receiver pack you will have to buy high voltage servos.

Afraid of brownout? One new alternative is the Scorpion Backup Guard for $25. It only kicks in when voltage drops in the danger zone. It sits quietly awaiting a low voltage supply to the receiver. Be wary, it's new but the features and benefits are very appealing. You charge it with 2s lipo charger only.

Last edited by Prof100; Mar 05, 2014 at 10:51 PM.
Mar 02, 2014, 08:42 PM
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Battery Tray and options

Morganmill makes a nifty Battery Cartridge system to handle the lipos better in the crowded battery compartment. It makes it much easier to install and remove the lipo. It's nickname is the the Large Wooden Contraption (LWC) and made from laser cut plywood. You glue it together. It fits right in the same location as the stock tray. Battery cartridge is locked in with a simple lever. Some buy mutliple battery cartridges som each pack has its own cartridge. Quite ingenious. Cost is less than $20 for the whole system. You glue together and install. You will need one ball driver to remove the front screws in the stock battery tray.

Below is shown the system that mounts in the plane and two cartridges. The wide laying down and the original size is standing vertical. Go with the wide so you don't fing yourself with too wide a battery for the cartridge. Gary at Morganmill may ONLY offer the wide these days anyway so my advice to buy the wide may be moot.

Last edited by Prof100; Aug 03, 2014 at 12:22 PM.
Mar 02, 2014, 08:42 PM
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Kavan lightweight 6" inflatables are $38 a pair not each. I know, I bought a pair. Shipping was another $10. The wheels and tires are lighter than the kit hard foam wheels. (PN 0266) from Sig Mfg or KAV0266. They are lighter than stock. A small brass fitting comes with it that you screw in to inflate. I will fly them as received. With a 5 mm axles on the CZC the smaller of the delrin inserts (3/16") have to drilled out with 13/64" (.203) drill.

Available on line from Sig which has the worst website of this century. Be patient finding them.

Last edited by Prof100; Mar 12, 2014 at 05:53 PM.
Mar 02, 2014, 08:43 PM
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Landing Gear

Cublandingear makes a pricey but hand crafted custom fit articulated landing gear if you want to spend $150 for custom fit gear. Robart also makes gear but you have to adapt them. The pricing is typical for 20% size articulated CUB gear. You have to remember, this plane is a giant scale 8lb. plane, not your run of the mill foamy.
Last edited by Prof100; Mar 07, 2014 at 11:18 PM.
Mar 02, 2014, 08:43 PM
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All servos are digital but DO NOT over volt them they will burn out. Below 6 volts is required. An unregulated A123 receiver pack will roast the servos per Richard Hanson.
Last edited by Prof100; Mar 13, 2014 at 07:40 PM.
Mar 02, 2014, 08:46 PM
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Painting and covering

Calliegraphics makes some 1" checkerboard 3M stick on vinyl decoration as well as some improved look for the cabin windows.

Ultracote covering can also be ironed on. Below is the Ulracote 1" checkerboard ironed on the rudder.

Painting is what is usually used if you have a favorite color scheme. For USA based customers you can purchase paint samples at Lowes using the following paint codes. Just copy the picture and print it out and take it to your Lowe's. With variation in paints at the store and the Eflite factory you will never have a 100% match.

Pledge / Future pure acrylic floor finish can be used to put a clear shine on the surface. Use a foam brush to apply. Got a run? No problem, just reapply and it will flow the run or sag. To remove use a weak solution of ammonia. Picture is below but it comes with many names. Below is a url to a remarkable blog post with more information that you ever wanted to have about Pledge Future;

Last edited by Prof100; Mar 12, 2014 at 06:07 PM.
Mar 02, 2014, 08:47 PM
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Wing struts

They are plastic and will break on a hard landing, especially in freezing weather. Buy a spare if you can find them. It is now early March. May is the expected delivery date. If they do fracture in the main section a couple of pieces of round CF can be glued into the slot to repair the break.

However, adding CF strengthens the struts if you tumble or crash the struts may not break but the mounting tabs on the fuselage may break which means you will have to buy a new fuselage.
Last edited by Prof100; Aug 03, 2014 at 12:28 PM.
Mar 02, 2014, 08:47 PM
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Wing bags to protect the foam

Wing bags can be made from your favorite material provided you know how to sew. See another post in my blog about the wing bags I made.

Below is how it comes from Home Depot:
Last edited by Prof100; Mar 12, 2014 at 10:10 PM.
Mar 02, 2014, 08:48 PM
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Stabilization Options

The BNF comes with A3X system and it works well but Coronna44 has installed a Eagletree Guardian and really likes it.
Last edited by Prof100; Mar 05, 2014 at 09:54 PM.
Mar 02, 2014, 08:53 PM
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Aluminum Spinner

Ordered and received an Eflite 2.5" aluminum spinner (EFLSP250) that replaces the plastic one. It's a bit pricey at $26 but it looks cool. It comes with 5mm and 6mm size collet adapter. The long screw requires an English hex head to install. Price is $26 plus shipping. Below is the $26 Eflite spinner. The prop slot has to be modified to fit larger, higher pitch props.

[Tru-turn with make a custom spinner for about $85. That is pricey.
Last edited by Prof100; Mar 12, 2014 at 06:03 PM.
Mar 02, 2014, 08:56 PM
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Mar 02, 2014, 08:57 PM
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Understanding motor temperatures


Originally Posted by Dr Kiwi

The 54C or 60C (temp max warning) is a fairly arbitrary number (but easy to "feel" by the finger tip test rather than having to measure it), but to my mind it relates to several factors (1) resistance increases with temperature..I think it is .......for copper 0.4% per degree C. Increased resistance is obviously not good. But (2) many motors use CA to glue in their magnets... many epoxies and CA's soften at ~60C. If your magnets come loose it doesn't really matter if they can withstand 200C! And (3) bearing oil doesn't like high temperatures and may escape if it gets warm and viscocity decreases, so your bearings may run dry.


I would say the 60C is far from arbitrary but quite well reasoned. Thanks.

Last edited by Prof100; Mar 13, 2014 at 09:47 PM.

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