Hacker EPP Piper Cub J-3 and Hobby Lobby eRC BL300 Motor Review - RC Groups

Hacker EPP Piper Cub J-3 and Hobby Lobby eRC BL300 Motor Review

Everyone loves a Cub! This one is built for having fun and learning to fly across most of the flight envelope.



Wingspan:1200mm / 47.28"
Wing Area:/ 25 dm. sq.
Weight:From 470g / 16.57oz.
Length:840mm / 33.07"
Wing Loading:6.15 oz/sq. ft. / 18.8 g/dm. sq.
Servos:GWS Naro +D 10g
Transmitter:9 Cap Super with TM-7 2.4 GHz 7 module
Receiver:Futaba R6106HF
Battery:800 mAh 11.v - 1500 mAh 11.v
Motor:eRC BL300
Propeller:Graupner Slowfly Prop 7x4
ESC:Castle Thunderbird 18
Typical Flight Duration:Ten minutes +
Available From:Available Late April

Each Cub version brings something to the airfield that reminds us of the history of aviation and that creates an enthusiasm for RC flying. I have flown Cubs from small foamies through giant scale, and each has a personality of its own. There is ne thing I would say about the ones I have liked: They tended to fly like a Cub; slow, deliberate, wide turns, stable in a stall and easy to land. Hacker’s EPP J-3 Piper Cub is one that meets my criteria of a great rendition of the venerable Cub, from the components, to matching the right engine, through the build and at the airfield; this Cub is an excellent addition to really anyone’s hanger.

Kit Contents

As an EPP model, the kit comes with well cut parts and components designed to specifically meet the needs of this Cub. The model is pre-painted with a light almost transparent coating with painted on decals, windows, panel detail and N-Numbers. The yellow is bright, but not as bright as some kits. The size is obvious, and this Cub has lots of qualities worth investing in and flying.

You will need a few items:

  • Four 9g servos
  • Prop
  • Brushless motor
  • ESC
  • Receiver
  • Two 12-inch extensions

I was lucky to have access to GWS's digital Naro + D servos. These are excellent 10 gram (.35 oz) servos and, contrary to the experience I have had with many digital servos, these DID NOT BUZZ. They were right on and strong with quick response and controllability. Since most usage is at the 4.8 voltage range the specifications include: 0.160 sec/60 degree and1.4 Kg/cm (22 oz.) torque. The measurements are consistent with just about any 9 -10 gram servo. GWS has a programming card available to set sensitivity, locked position when out of signal and rotation range using a neutral point and two end points.

I contacted Hobby Lobby International with the requirements necessary to get the right brushless motor. Their line-up of eRC motors was perfect, and with a little help, we decided on the BL300. Hacker proposes an 80W motor, but also one that is 28mm wide, 15mm deep and in the 1400-1500KV range. The BL300 motor was suggested knowing we were going to be pretty close at 1400KV. It fit perfectly with no trimming. In the end, this was absolutely the perfect motor. Each eRC motor has a one year warranty.

Hobby Lobby suggested one of their Graupner slowflyer 7 x 4 glass-fiber props to go with the BL300 eRC motor. This turned out to be a great combination.


The manual is well illustrated and is translated in at least five languages. Billed as a “Top Flyer Almost Unbreakable” aircraft, the Hacker Cub assembly is easy to follow, and I found nothing left out that would lead to an incorrect build. The process starts with the wing and ends with the battery hatch. If I adapted anything in the assembly it was to get the mains on as soon as possible to get the fuselage standing upright. Let’s do a little walk around of the Hacker Cub.


The wing is a two-piece design and requires the installation of a wooden main spar. Because this is EPP you can use regular CA glue. Be careful to not over accelerate the drying as heat will damage the foam.

After you install the spar, the wing halves must be joined with a slight dihedral. I cut a piece of ruler to use to get the correct spacing between the wing tip and the table top. The center rib fit well with this slight angle. A main wing joiner is provided that is plastic and glues the two halves together. The J-3 does not use wing struts.

The servos are installed at this time and require you to cut into the wing to make the servo fit. While it seems like extra work, this method ensures the cut fits your servo. I used hot glue to hold the servos.


The fuselage is basically built and ready to go. You need to add the tail, firewall, wing attachment pins and landing gears. I started with the motor mount.


The tail is similar to the wing and attached in a conventional manner. Flex the elevator and rudder some to make them move easier, bit otherwise the build here is simple.

Landing Gear

The main gears are simple to install, but a little more effort is required for the steerable tail wheel.

Radio Installation

I used a Futaba R6106HF 2.4 GHz receiver with my trusty Futaba 9 Cap Super equipped with a TM-7 module. The light weight versatility of this setup provides you some options with battery selection, and it is a great 2.4 setup designed by Futaba. The ESC tucks up behind the firewall and on top of the battery platform and reaches just inside the fuselage under the wing. The battery is located to meet the 65mm CG from the leading edge.


The final items needing completion include the battery hatch and wing mounting, which are ot too difficult. My amp draw was 9 amps, and my wattage was 87 in the end, so I was pretty much on target with Hacker’s recommendation.


  • 10mm up and down
  • Elevators 10mm up and down
  • Rudder 15mm right and left


My initial flights were what I expected with regard to turns. I quickly landed and dialed in some rudder to coordinate the turns and the Cub performed much better. I used about 30% expo on the sticks to soften my inputs and slow the rate of control to a more realistic flight. I did not experience any really poor or uncorrectable flight characteristics that made me uncomfortable, and as I flew the Cub more and more I began to try a few larger batteries from the original 800 mAh LiPo. In the end, I was up to a 1500 mAh (135g) and as long as the battery is narrow enough I am pretty sure I could have added an even larger battery. Final flight weight was up to 561 grams. The Cub can haul a load, and in fact I think flies better with some weight. The CG is right under the wing spar so whatever battery you use it has to be shoved up inside the fuselage. The battery opening is really to reach the battery and ESC leads, but with the BL300 motor I used, the weight had to stay aft some ways.


I have flown the Cub quite a bit, and each time I continue to tweak the mixes on my Futaba 9 Cap Super. I added some up elevator too for the turns and this improved the flight character. I was a little disappointed that even though I had the motor firmly against the firewall I felt the throttle was also controlling the altitude. I mixed in a little down elevator to the throttle to compensate, but spacers behind the motor would have also worked. Turns, once coordinated, are nice and level, and the plane holds true in a straight line after my combination proved the need to dial in some tail control. The glide slope is great. Full throttle stalls dipped the left wing and power-off stalls were a gentle nose drop with easy recovery.

Taking Off and Landing

The takeoff roll does require some rudder, but the lift-off is quick. I did not have too much trouble keeping the Cub straight. The prop has a scale distance to the runway so you have to keep the plane level on the takeoff to avoid a tip hit. The landings are absolutely a joy. I love setting up a plane to land and basically just following it to the runway with little stick input. This is a wonderful plane to learn on, and the EPP foam is as durable as any RC plane material can be. You can roll the Cub on landings with no damage. The landing gear is durable too.

Aerobatics/Special Flight Performance

I thought the basics were all doable. I could pull loops easily and they were nice and straight. Rolls were floppy, and it takes a lot if aileron to get the Cub over and then a lot of elevator to keep it level. The dihedral in the wings fought my inputs to right the Cub. Inverted flight was stable, a show stopper for your less accomplished pilot friends. While upside-down the Cub wants to nose up, so I found the need to keep pushing the nose down. Overall I thought it flew like a Cub should without the BL300 motor. I was very pleased.

Is This For a Beginner?

It would be hard to not categorize the Hacker Cub as a beginner aircraft. It flies slow, is controllable and can re-enter the atmosphere for landings like beginners dream. I really loved the flight style. I also thought the build sequence was well thought out, plans were easy to understand, and when done, it looked like a Cub. There's really no reason not to try this plane.

Now that being said, I thoroughly enjoyed flying the Cub, and I consider myself at least an experienced pilot. You can polish your tail dragger skills, landings and use of mixes. I like the fact that I have some flexibility in battery choice and consider this a great park flyer capable of flying everyday in some winds.

Flight Video/Photo Gallery



This Cub has a lot of potential. It presents itself as a beginner aircraft but has all the ability to bring satisfaction to even the most seasoned flyer. It can do mild aerobatics, but land easily. One could add floats, or given I have not even come close to the load this plane will haul, try lots of batteries or camera equipment. I liked the build and instructions and see nothing to keep a new flyer from having a successful experience. I recommend the Hacker Top Flyer Almost Unbreakable Cub and hope it gets to the market very soon for total distribution and access.

Special thanks to Hobby-Lobby International and Grand Wing Systems for their support.


  • Pre-painted, decaled and detailed
  • The Cub can haul a load
  • EPP


  • Narrow rubber band protectors
  • CG does not align with the batery hatch.
Last edited by Angela H; Jun 10, 2011 at 08:37 AM..
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Jun 01, 2011, 04:52 PM
Senile Member
Lnagel's Avatar
$149.00 for a hunk of EPP foam that somewhat resembles a lemon yellow Piper Cub. What a deal! I'll be the first on my block to get one.

Jun 01, 2011, 07:03 PM
Registered User
for the price of this ARF you could get a balsa and ply Addiction from PA that will do 3D like no tomorrow.

good review
Last edited by moser5; Jun 01, 2011 at 11:11 PM.
Jun 01, 2011, 08:27 PM
Air Cooled VW mechanic
THX-181's Avatar
Well written with a wealth of detail photos.
Thanks Dave.

I will also take issue with the price, if only so the folks at Hacker might figure out that their prices are WAY out of line.
$150... are you kidding me?? For that price it would have to come with a motor/ESC combo to even be competitive.
Good heavens... It's pre-sale on Ebay at $175.
Jun 01, 2011, 11:58 PM
Registered User
I'm not sure where that price came from, Hacker's retail price for it is $101.50.
Jun 02, 2011, 02:54 AM
Air Cooled VW mechanic
THX-181's Avatar
Originally Posted by World Toy
I'm not sure where that price came from, Hacker's retail price for it is $101.50.
Your website has it priced at $111.75
Jun 02, 2011, 11:11 AM
Registered User
Our website has the suggested prices. When the new shipment arrives our dealers should have them at the lower retail price.
Last edited by World Toy; Jun 11, 2011 at 05:14 PM.
Jun 02, 2011, 01:02 PM
Senile Member
Lnagel's Avatar
The $149.00 price came from the right sidebar at the beginning of the review. At $100.00+ it is still more than twice as expensiver as it's worth.

Jun 10, 2011, 10:28 AM
Professional tree finder
minivation's Avatar
I am using the eRC BL300 on my TW Lanyu Cessna. Works beautifully! Great review.
Jun 28, 2011, 09:23 PM
Heavy Chevy's Avatar
Just from the pics and price, I'd sooner go with something that looks better and is more RTF from Hobbyking. Great review though
Jun 29, 2011, 06:37 AM
Suspended Account
Dan5.0's Avatar
Originally Posted by moser5
for the price of this ARF you could get a balsa and ply Addiction from PA that will do 3D like no tomorrow.
yeah I guess, and one doink and you'll have $150 worth of toothpicks PA SUX!!!!
Aug 18, 2011, 09:22 AM
Registered User
Rat Brother 1's Avatar
I agree, nice review but they have the pice point all wrong. This should be a $70 kit, no more. Seriously.
Aug 20, 2011, 09:10 AM
Professional tree finder
minivation's Avatar
About the eRC BL 300 - I've been using one of two for about half an year on that Lanyu, (and yes, it has been working beautifully) but after running the motor for a 8+ minute flight, I find it darn hot! I mean, BOILING! However, nothing's going bonkers with the bearings or magnet wires, it's just simply hot. I run 11.1V 25-35C, using a variety of batteries from Tower Hobbies to Rhino to Turnigy. ESC is HiMax 18A. Propeller is 9x6.

Anybody else have similar issues?

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