RE: E-flite J-3 Cub 25 ARF (Full Version)

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Greg Covey -> RE: E-flite J-3 Cub 25 ARF (7/31/2006 1:20:15 PM)

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 -> RE: E-flite J-3 Cub 25 ARF (7/31/2006 1:36:26 PM)

I charged the ThunderPower 4200mAh pack with a Cellpro 4s Balancing Charger and ThunderPower to Cellpro Adapter 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 -> RE: E-flite J-3 Cub 25 ARF (7/31/2006 3:02:08 PM)

quote:

ORIGINAL: Greg Covey

I charged the ThunderPower 4200mAh pack with a Cellpro 4s Balancing Charger and ThunderPower to Cellpro Adapter from FMA Direct. All three products are available from Horizon Hobby.

SNIP


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 -> RE: E-flite J-3 Cub 25 ARF (8/1/2006 2:20:22 PM)

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 -> RE: E-flite J-3 Cub 25 ARF (8/1/2006 5:33:32 PM)

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 -> RE: E-flite J-3 Cub 25 ARF (8/1/2006 9:20:55 PM)

quote:

ORIGINAL: Greg Covey

Hi Charley,

Keep in mind that two 3-cell 2100mAh ThunderPower packs are no less expensive than a single 3s2p 4200mAh pack.




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 -> RE: E-flite J-3 Cub 25 ARF (8/3/2006 6:12:22 PM)

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 -> RE: E-flite J-3 Cub 25 ARF (8/4/2006 8:37:59 PM)

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:

  • 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




matt7rc -> RE: E-flite J-3 Cub 25 ARF (8/4/2006 11:34:42 PM)

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 -> RE: E-flite J-3 Cub 25 ARF (8/5/2006 3:19:45 AM)

quote:

ORIGINAL: 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


The word is "strapped."

CR



Phoenex -> RE: E-flite J-3 Cub 25 ARF (8/5/2006 3:44:00 PM)

quote:

ORIGINAL: Charley

quote:

ORIGINAL: 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


The word is "strapped."

CR


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



Charley -> RE: E-flite J-3 Cub 25 ARF (8/6/2006 2:56:14 PM)

quote:

ORIGINAL: phoenex



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


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 -> RE: E-flite J-3 Cub 25 ARF (8/7/2006 1:00:54 PM)

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



Tall Texan -> RE: E-flite J-3 Cub 25 ARF (8/7/2006 4:46:21 PM)

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 -> RE: E-flite J-3 Cub 25 ARF (8/7/2006 5:27:02 PM)

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



Tall Texan -> RE: E-flite J-3 Cub 25 ARF (8/7/2006 9:14:28 PM)

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.



Tall Texan -> RE: E-flite J-3 Cub 25 ARF (8/7/2006 9:19:06 PM)

Here are a few pics.




Tall Texan -> RE: E-flite J-3 Cub 25 ARF (8/8/2006 12:51:44 AM)

Well, lets try this again.



Greg Covey -> RE: E-flite J-3 Cub 25 ARF (8/8/2006 1:53:24 PM)

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.

J3 Cub 25 Video 1 (10meg)



Glacier Girl -> RE: E-flite J-3 Cub 25 ARF (8/8/2006 4:31:20 PM)

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.



fiddy_zen -> RE: E-flite J-3 Cub 25 ARF (8/11/2006 6:13:42 AM)

This is a very nice looking plane. How is the ground handling and takeoff? I built and flew a Carl Goldberg Cub about 10 years ago. On takeoff had to feed in quite a bit of rudder to keep it strait and also lots of up elevator to keep it from nosing over. Would this model be the same in that regard? Thanks



John Redman -> RE: E-flite J-3 Cub 25 ARF (8/11/2006 2:40:24 PM)

You still need the rudder at times during the takeoff roll, just a natural tendancy of the Cub. But there are no habits of the plane nosing over during takeoff or landing, that will not be a problem I promise you.

The plane loves grass takeoffs, but of course does takeoffs from pavement just as well.



Greg Covey -> RE: E-flite J-3 Cub 25 ARF (8/11/2006 3:53:22 PM)

I agree with John in that you will always need some rudder correction on take-off and this applies to most scale models.

It is time to try out the optional E-flite 25-Size Fiberglass ARF Floats (EFLA500). The E-flite quick-mount floats are designed specifically for 25-size planes that are float-ready out of the box, so you can go from pavement to pond in just minutes. I plan to video the J3 Cub 25 on floats taking off from both water and grass.




Tall Texan -> RE: E-flite J-3 Cub 25 ARF (8/11/2006 4:32:08 PM)

I noticed with mine that the rudder does not want to come back to center due the flex in the tube/cable assembly. Where the instructions say to place the last brass clamp is apparently not far enough back towards the tail. However, when I look at it, there isn't enough room back there to mount the clamp there. Any suggestions as to a fix. Has anyone else noticed this or had this problem?



Charley -> RE: E-flite J-3 Cub 25 ARF (8/11/2006 4:54:41 PM)

quote:

ORIGINAL: Tall Texan

I noticed with mine that the rudder does not want to come back to center due the flex in the tube/cable assembly. Where the instructions say to place the last brass clamp is apparently not far enough back towards the tail. However, when I look at it, there isn't enough room back there to mount the clamp there. Any suggestions as to a fix. Has anyone else noticed this or had this problem?



Looks like the cable comes in to the horn at an angle, putting things in a bind. You might cut a bit off the tube to expose more of the cable. Then bend the cable end to where it's parallel with the pushrod. This assumes (that word again) that the rest of the water rudder mechanism moves freely. How well does your rudder servo center otherwise?

BTW, I notice that there is only one water rudder. How well does the model turn to the side opposite the water rudder?

CR



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