Glacier Girl

My Feedback: (4)

Greg,
As another Northern boy, what do you think of using the Dubro 825 snow skis on the Cub?
Might as well plan on winter flying too.

Greg Covey

Although the Dubro skis should work fine, it has been my experience that floats work well in the winter time too.

Greg Covey

The E-flite 25 motor comes with the motor mount, collet prop adapter, connector mates, hex wrenches, and all hardware needed. Likewise, the E-flite 40-amp Brushless ESC also comes with the connector mates. Both these E-flite products come with mating connectors and they each have their own connectors already soldered on. You only need to screw in the X-type mounting bracket and solder on a mating connector for the ESC-to-battery connection.

I also received an Expert (EXRB100) 4-cell, 4.8v, 720mAh AAA NiMH receiver pack to eliminate the need for the BEC feature on my ESC. This is used in conjunction with the Expert (EXRA050) Standard Switch with charging cord so you recharge it right in the plane.

I was a bit dissapointed when I discovered that the pre-mounted t-nuts in the J3 Cub 25 were a different size than the included hex screws that came with the motor. Although the matching screws for the pre-mounted t-nuts came with the J3 Cub kit, they were too large for the X mount holes requiring you to drill them out. This makes for lots of metal fragments so it is best to drill the holes out before you attach the X mount to the motor.

John Redman

My Feedback: (8)

Hey Greg,

Seems like the build is going well for you.

You have found the one main issue we have with this Cub and that is the X-mount screw size. The kit comes with 6-32 and the mount is drilled for 4-40. This was a screw up on my part, the factory did what I told them. Still not sure how that one got by. The next batch of kits will have this fixed.

Wait till you fly it, I think you will be happy.

Greg Covey

Hi John,

Thanks for checking in. Fortunately, it is an easy fix to open the holes a bit in the X-mount. I think my reaction was more of a surprise because I didn't expect it and assumed it would plug-n-play like everything else has on the J3 Cub 25. I'll note it in my review so people know to check it before screwing the X-mount onto the motor.

Greg Covey

The E-flite 25 motor attaches to the pre-mounted t-nuts in the firewall. Remember to use some thread locker on these screws as well as the screws holding the X-mount to the motor. I decided not to mount the ESC to the side wall with Velcro (hook and loop) as it is held in position quite well by the thick wires and battery pack. We'll see if this works out during actual use.

The cowl was held in place while I drilled pilot holes for the 4 mounting screws. Some folks like to use masking tape to temporarily hold the cowl in position while drilling.

The prop adapter is designed to fit the APC 12x6 e-prop perfectly without and bushing. The collet design simply presses in place and is then tightened. I use the largest size hex wrench that will fit through the hole in the spinner to tighten it.

Greg Covey

I charged the ThunderPower 4200mAh pack with a [link=http://www.fmadirect.com/products.htm?cat=45&nid=4]Cellpro 4s Balancing Charger[/link] and [link=http://www.fmadirect.com/Detail.htm?item=2125&section=45]ThunderPower to Cellpro Adapter[/link] from FMA Direct. All three products are available from Horizon Hobby.

Since this charger can safely recharge the pack in the plane, I mounted the battery with Velcro on the bottom and two Velcro straps. This combination holds the 10oz pack securely in place without any sliding. Note that the fuselage hatch is held in place by two strong magnets.

Charley

My Feedback: (2)

Whoa! I thought you were going to try the NiMH pack first. Or was that too?

A friend of mine is putting a Cub together. He's using two 2100s in parallel to hold down the battery cost and be able to use them in other E-birds.

CR

Greg Covey

Hi Charley,

I haven't tried anything yet...it's only a picture of the mounting scheme and safe charging technique. Keep in mind that two 3-cell 2100mAh ThunderPower packs are no less expensive than a single 3s2p 4200mAh pack.

The struts simply screwed into place using the supplied hardware and pre-tapped holes.

Greg Covey

The finished E-flite J3 Cub 25 balanced perfectly with either pack installed and weighed 59oz (3.7lbs) Ready-To-Fly (RTF).

The power system measured 350 watts at 33amps for about 95w/lb which guarantees aerobatic performance.

Charley

My Feedback: (2)

Not necessarily, Greg. Besides, we don't all use Thunder Power packs. I have Kokam & Common Sense packs, some others. Flexibility is also a consideration.

BTW, the two 2100s fit fine if stood on edge.

Looking forward to the flight testing.

Cheers,

CR

donjiskra

Greg,
Your step-by-step photos and remarks are excellent.
As always, you are a true master, I learn much from you.

I plan on getting this plane, as a replacement for my Hobby Lobby "Bonnie", which I recently demolished. The "Bonnie" is/was an incredible flyer, especially with floats.
I plan on using the AXI 2820/10 motor that was in the "Bonnie" and the 4200mah lipo, whioch provide 20 minute flights on a 10x7 APC-E prop.

Can't wait to read about your flight review and see te video.

BTW, the gentleman that asked about using skis.
I found that floats work much better, as my experience with skies, showed they tend to dig into light snow.

Thanks Greg, for taking the time to write and provide such great photos with awesome resolution.

Happy flying.
Don

Greg Covey

Hi Don,

Thanks. Sorry to hear that your Bonnie 20 met with demise. It is a similar size to the E-flite J3 Cub 25 so you should be a happy R/Cer once again. The .25-size planes have some advantages in that they are manageable by most as an all occasion flier. The quick change floats on the J3 Cub 25 enhances that property even further.

The 10-cell E-flite 1800mAh 4/5A NiMH pack mounts in the same manner as the optional LiPo pack. It adds another 3oz to the flying weight.

The Expert (EXRB100) 4-cell, 4.8v, 720mAh AAA NiMH receiver pack adds another 2oz and is best mounted across the CG as shown when using the LiPo pack. It can also be mounted below the servo tray on top of the framework for the gear mains. When using the 10-cell E-flite NiMH pack that weighs 12.8oz, move the Expert receiver pack aft by about 3" for proper balance.

The Expert receiver pack is used in conjunction with the Expert (EXRA050) Standard Switch with charging cord so you recharge it right in the plane. This eliminates the possibility of a BEC failure under extreme heat, humidity (thicker air), and servo drain conditions. I am not certain if it has been determined that this conditions happens often enough to justify the setup. It is a recommendation by Horizon Hobby for safety due to the specifications of the ESC's BEC output.

The 8% range of flying weight due to various setup is as follows:[ul][*] 59oz (3.7lbs) with LiPo option and using BEC in ESC[*] 62oz (3.9lbs) with NiMH battery pack and using BEC in ESC[*] 64oz (4.0lbs) with NiMH battery pack and using Expert receiver pack
[/ul]

matt7rc

i bought the e-flight j-3 cub for its size and looks but i cant get use to batteries so right out of the box i straped a o.s 25 la on her and let me tell you the thing is a blast to fly

Charley

My Feedback: (2)

The word is "strapped."

CR

Phoenex

My Feedback: (1)

This is not an English class forum...get over it

Charley

My Feedback: (2)

You need help too; the word is "phoenix." ;^) Or is that some sort of play on the word?

On a more serious note; I wonder how long it will be before that OS 25 shakes the Cub's nose apart.

CR

Greg Covey

We test flew the J3 Cub 25 yesterday and had total success. It simply flew as expected...magnificent!

The E-flite 25 outrunner provided awesome power which means my next test with floats is guaranteed to be successful. The NiMH pack provided about 10 minute flights and the 4200mAh LiPo pack about 20 minute flights.

I'll post the video soon...

photos by "Papa Jeff" Ring

COL J

Greg,

Very nice and informative review. I have mine completed now. The floats were on backorder for awhile. Have not flown it as yet because my radio is at JR SVC for a check-up and replacement of the Li battery.

I did buy a Hobby Lobby Ultimate BEC for it but haven't put it in. Where I fly, here in the northern part of the State of Washington, it does not get too warm. I put the THunder Power 4200 pack in it. So with any luck this week I will do some taxing tests on the water. Will attach a couple of pics.

Charley

My Feedback: (2)

Hay Tex,

How'd the float installation work out? Did you just bolt 'em on or customize to get the CG and the steps in the right place?

Thanks,

CR

COL J

Charley,

Yes, I basically assembled them and put them on per the instructions. I used the Thunder Power 4200 mah pack and shoved forward as far as it would go and the CG came out just fine.

COL J

Here are a few pics.

COL J

Well, lets try this again.

Greg Covey

Nice photos! I can't wait to try my floats now.

Here is my first video on land with the stock wheels. The winds were rather brisk for a 25-size plane at 10-15mph but the Cub proved to have plenty of power.

[link=http://www.gregcovey.com/reviews/EfliteJ3Cub25.wmv]J3 Cub 25 Video 1[/link] (10meg)

Glacier Girl

My Feedback: (4)

Nice vid Greg. She seems to be a real floater. I imagine using the ailerons as a flap arrangment you could make her nearly into a VTOL. She should do fine on the water.