Eflite J-3 Cub 450

Eflite J-3 Cub 450

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Current Power Setup

  • Motor: Eflite Park 480 1020Kv, 22A/28A max, 275W, 87g
  • ESC: Eflite 30A Pro V2, 30g
  • Prop: Falcon 12×6 wood
  • Batteries: Admiral Pro 3S 2200mAh 45C, 186g
  • Amps, Static: 29A w/Falcon 12×6 wood prop and 3S 45C battery

Previous Power Setup

  • Motor: Power Up 450 880Kv, 240W, 18A max, 71g
  • ESC: Sky Power 20A, 19g
  • Prop: APC 11×8.5e, 10×7 wood
  • Batteries: 3S 2200mAh 30C, 3S 1300mAh 50C

Current Radio Gear and Setup

  • Transmitter: Spektrum DX18 G1
  • Receiver: Lemon Rx DSMX-Compatible 7ch Stabilizer w/Diversity Antennas, LM0033
  • Aileron Differential: 14.3%/2mm
  • Servos (4): Emax ES08DE 8g Digital

Previous Radio Gear and Setup

  • Receiver: Spektrum AR610

Current Specs

  • Wingspan: 51″ or 1300mm
  • AUW: 35.7oz or 1013g (plane: 827g)
  • CG: 1.6″ or 40mm aft of wing leading edge
  • Flight Time: 7.5 minutes

Manuals, Specs and Instructions

Power Setup Swap
My original plan was to build the Eflite J3 Cub 450 light but after flying 3 batteries with the Power Up 450 motor, which is supposed to be more like a Park 480, I immediately changed over to an Eflite Park 480 motor with a 12×6 prop. Much better!

Receiver Update
I wanted stabilization for more scale-like flights and the Eflite Cub 450 can get pushed around slightly by wind gusts so I swapped out my original Spektrum AR610 receiver with a Lemon Rx LM0033 DSMX-Compatible 7-Channel Stabilizer Receiver with Diversity Antennas. The Lemon Rx 7ch Stabilizer Receiver is very easy to setup, using simple potentiometers to adjust each axis gain with an overall gain adjusted remotely from the rotary knob on my DX18 transmitter.

Wing Bolt Covers
I didn’t care for the wing bolts and recesses showing on top of the J3 Cub 450 wing so I switched out the included black Allen head wing bolts with button head cap screws so they don’t stick up above the wing. Then I used a super sharp cigar punch to cut nice little circles out of Hanger 9 UltraTrim Cub Yellow trim tape to cover the unsightly recesses, as shown below.

Eflite J3 Cub 450 wing bolt covers with Hanger 9 UltraTrim
Eflite J3 Cub 450 wing bolt covers with Hanger 9 UltraTrim

ESC Placement
The photo below shows where I mounted the ESC in my Eflite J3 Cub 450. Under the ESC you will notice a coating of epoxy. I do this on all of my balsa planes where I place Velcro or double-sided tape when mounting ESCs, batteries, receivers, etc. The Velcro and double-sided adhesive sticks well to the smooth surface and is much easier to remove if needed. If you have ever tried to remove good double-sided tape like 3M from soft wood, you will appreciate this tip! I just use 5 or 30 minute epoxy on an acid brush and coat the wood. When the epoxy is completely dry, I use isopropyl alcohol to clean off any residue. You will also notice on the J3 Cub 450 that there is a switch mount already cut in the wood on the left side in case you want to mount a receiver on/off switch.

ESC mounted to the inside bottom of fuselage
ESC mounted to the inside bottom of fuselage

Battery Placement
One very minor drawback to the Eflite J3 Cub 450 is battery placement. The plane needs to be flipped upside down to install the battery. It’s not bad if you have something soft to put the wing on. I have a small foam rubber stand that I picked up from HobbyKing for less than $6. It comes apart easily and fits in my transmitter case, which is a plano 4-pistol gun case.

The photo below was taken on my original build when I started with 3S 1300mAh batteries. The 3S 2200mAh batteries fit similarly. The photo was also taken without a Velcro battery strap which I use.

Battery in tray of Cub 450 with plane upside down
Battery in tray of Cub 450 with plane upside down

Fuselage Air Exit Holes
The Eflite J3 Cub 450 has two holes in the wood in the bottom rear of the fuselage but the covering on mine was not cut out. I read that the air exit holes are not really required with the recommended power setup. However, with my power setup all pretty close to max spec (motor 28A max, 30A ESC, 29A with fully charged 3S 45C), I opted to remove the covering over the holes to ensure good airflow for the electrics.

Air exit holes cut in covering at rear of fuselage
Air exit holes cut in covering at rear of fuselage

Optional Flaps Installation
Most folks say the J3 Cub doesn’t need flaps because it flies slow enough with its big wing. Being interested in STOL aircraft, I was curious how hard it would be to modify the Eflite J3 Cub 450 for flaps. I laid out some parts to see what it would look like and it doesn’t look too complicated. Maybe when I finish a few other projects I will tackle flaps on my Eflite J3 Cub 450.

Eflite Cub 450 wing with flap components laid out
Eflite Cub 450 wing with flap components laid out

Wing Backlit Photo
Back-lighting the Eflite J3 Cub 450 wing shows that installing full length flaps are easily feasible. They could go from the edge of fuselage center section out to the aileron. A single servo could be mounted in the skylight opening with just a little reinforcing. The wing center section and flaps could be the only items needing recovered.

Eflite Cub 450 wing backlit to see spars
Eflite Cub 450 wing backlit to see spars

Tundra Wheels
I put a set of 3-1/2″ lightweight foam tundra wheels on my Eflite J3 Cub 450. They are the optional “Island Wings Tundra Wheels” for the Flyzone Beaver, painted yellow with Krylon Short Cuts aerosol. I found them when looking for lightweight bush wheels for my Multiplex Pilatus.

Eflite Cub 450 with lightweight foam bush wheels
Eflite Cub 450 with lightweight foam bush wheels

Eflite J-3 Cub 450 Overview
Outside of adding tundra wheels, future suspension main landing gear, and a few little mods here and there, I really have not done much out of the ordinary to my Eflite J3 Cub 450. It was an nice, easy and clean build. I’m very happy with it!

9/28/2016 Update: Main Gear Shock Absorption & Wheels
I flew my Eflite J3 Cub 450 for the first time with the Flyzone Beaver Tundra wheels and it did not do well with the solid fixed main gear and stiff foam wheels. So in the meantime I switched out the foam tundra wheels to Dubro 2.5″ Low Bounce rubber wheels and added strips of rubber (rubber band pieces) in the main gear slots in the fuselage as shock absorption. Works great! Lands and taxis a lot smoother.

Eflite Cub 450 Landing Gear Cushions
Eflite Cub 450 Landing Gear Cushions
Eflite J3 Cub 450 Videos

Video with Spektrum AR610 receiver:

Video with Lemon Rx Stabilizer receiver:

Close-ups, Feedback and Reviews
To be more mobile friendly, photos on TazRC are limited in size. I would be happy to post any close-up photos on request. Just leave a comment below. Also, feel free to leave your feedback or personal review on the Eflite J-3 Cub 450. Registration not required.

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