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-   -   E-flite J-3 Cub 25 ARF (https://www.rcuniverse.com/forum/electric-aerobatic-sport-planes-144/4496267-e-flite-j-3-cub-25-arf.html)

fiddy_zen 08-11-2006 12:13 AM

RE: E-flite J-3 Cub 25 ARF
 
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 08-11-2006 08:40 AM

RE: E-flite J-3 Cub 25 ARF
 
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 08-11-2006 09:53 AM

RE: E-flite J-3 Cub 25 ARF
 
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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.


COL J 08-11-2006 10:32 AM

RE: E-flite J-3 Cub 25 ARF
 
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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 08-11-2006 10:54 AM

RE: E-flite J-3 Cub 25 ARF
 

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

COL J 08-11-2006 12:07 PM

RE: E-flite J-3 Cub 25 ARF
 
I can't tell any difference in the water left or right. You are right, I should have noticed that. Sometimes with these ARFs you get so tied into to following instructions you just overlook. Haven't actually flown it as yet. Just got my radio back from JR and had it on the lake yesterday doing some taxiing. Don't know yet if I am going to see any water in the battery area from the vent holes in the hatch. Hope to fly it this weekend.

FlyingGuy 08-11-2006 04:21 PM

RE: E-flite J-3 Cub 25 ARF
 
Hi Gents. Anyone hand-launch the E-Flite Cub and recover it in high grass, sans landing gear? My favorite field is the home of the belly landing. Thanks!

John Redman 08-11-2006 09:00 PM

RE: E-flite J-3 Cub 25 ARF
 
Follow the instructions on taxing and take off with floats and you shouldn't see any water up in the battery area. If you fly when there is small chop on the water, then you will see some small amount of water make it into the battery area. Either way it isn't a big deal. My Cub has better than 200 landings on it and I would venture to guess better than 100 flights on it since I put it together, it is still wokring without issue.

We haven't seen any real problem with the rudder not coming back to center when it is attached to the water rudder. As mentioned you might want to trim the plastic housing a bit to eliminate some of the binding I am sure you have. I thought the picture showed more or less where to cut it off in the instructions, it might not. The tube length needs to work with both teh Cub and Ultra Stick 25e (which needed to be a bit longer). Another question would be what servo do you have on the rudder. We tested the plane with JR Sport MN-48's and never had the problem.

As stated in the instructions, bury your elevator for the start of the take off run when on floats, and once speed begins to build, begin to relax the elevator until she comes up on step. The process moves along very quickly and you will be in the air in less than 250 feet once you get used to it.

I think you will really enjoy it on the water, I know I do.

Greg Covey 08-13-2006 11:09 AM

RE: E-flite J-3 Cub 25 ARF
 
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The float assembly went without a problem as the instructions were simple and well written. The J3 Cub 25 is also a float-ready design by E-flite.

After removing the stock gear mains, I cut the covering off the rear most channel and mounted the float mains. Next, the brackets were screwed into the floats and flat spots filed onto the tops of the float mains for better hold by the wheel collar set screws. I used a Dremel tool grinder to make the entire top of the float mains extensions flat.

The floats were then mounted and the collars secured using Pacer Z-42 Thread Locker. Note that there is one float with extra holes in the aft end that is meant to mount on the side were the rudder linkage is located.

The ventral fin mount is screwed into place in the pre-drilled holes under the Cub fuselage. After cutting away some covering, the fin itself is glued into the mount with epoxy. I used 5-minute ZAP Z-poxy.

Next up...linkage and water rudder installation.

Charley 08-13-2006 01:02 PM

RE: E-flite J-3 Cub 25 ARF
 

ORIGINAL: John Redman


As stated in the instructions, bury your elevator for the start of the take off run when on floats, and once speed begins to build, begin to relax the elevator until she comes up on step. The process moves along very quickly and you will be in the air in less than 250 feet once you get used to it.

250 feet? Is that a typo? My GWS Tiger Moth 400 gets off the water in <25 feet and that's on the stock can motor with a 3 cell LiPo.

CR

John Redman 08-13-2006 09:42 PM

RE: E-flite J-3 Cub 25 ARF
 
No that isn't a typo. 250 feet is a normal run on water with a 5.5 pound bird. How much does your Tiger Moth weigh?

Greg Covey 08-14-2006 07:19 AM

RE: E-flite J-3 Cub 25 ARF
 
John,

The TM400 is a smaller foamie parkflyer that weighs about 20-24oz with floats. It isn't a valid comparison...much like apples to oranges. You can see my review on it [link=http://www.rcuniverse.com/magazine/article_display.cfm?article_id=345]here[/link].

We have already decided that the J3 Cub 25 should not be considered a parkflyer due to its size, weight, and power level.

Charley 08-14-2006 07:53 AM

RE: E-flite J-3 Cub 25 ARF
 

ORIGINAL: John Redman

No that isn't a typo. 250 feet is a normal run on water with a 5.5 pound bird. How much does your Tiger Moth weigh?
Got to admit that my TM-400 weighs less than 2 lbs with the floats and water rudder and it has lots of wing area too. But it's powered by the stock, geared, speed 400 brushed motor.

John, I'm not knocking your Cub, after all it's your rice bowl, but 250' is almost the length of a football field. I've done lots of float flying with models ranging from .10 to .60 size and if any of them wouldn't get off in less distance than that, I'd be seriously concerned about my setup.

I have a feeling you're over estimating the TO distance of your Cub. Maybe Greg can get us an estimate during his upcoming ROW test flights.

CR

Greg Covey 08-14-2006 04:02 PM

RE: E-flite J-3 Cub 25 ARF
 
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Yeah, we can test a scale take-off and then see what it can do on full throttle. Assuming calm water, it's a blast to let it ride on step for a while.

The water rudder and linkage assembled fine and I did not see any excessive resistance added to the rudder throw. My only modification was to make two of the full brass strips into half strips for easier mounting. I used a Dremel tool to cut off the unwanted end.

I also managed to break one of the quick links so I replaced it with a similar size one from my own supply. There was about 1/2" excess cable that I cut off from the float end.

When testing the water rudder assembly, make sure that it follows the normal rudder direction and that it can flip up with little resistance if it hits a rock or some obstruction in the water.

Greg Covey 08-14-2006 04:10 PM

RE: E-flite J-3 Cub 25 ARF
 
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The Cub looks great with the floats attached. I can't wait to test it out but I must travel for work this week. Perhaps this weekend sometime.

Greg Covey 08-15-2006 08:13 AM

RE: E-flite J-3 Cub 25 ARF
 
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I mounted the On/Off switch in-line with the black stripe to keep it from detracting from the scale look of the Cub. You can either re-route the ESC's throttle signal pin into the output of the switch wire connected to the receiver or use the receiver battery pack option. The On/Off switch provides added safety and convenience when connecting the battery pack or finishing a flight.

COL J 08-15-2006 10:56 AM

RE: E-flite J-3 Cub 25 ARF
 
Greg,

This sounds neat except I not sure how you wired the on/off switch into the ESC. That would be nice to turn the ESC on/off after you have connected the battery. Would like to see how you did this. Do you simply use the ESC rcvr signal lead and plug it into the switch and then plug the switch lead into the throttle port on the rcvr?
Thanks

Greg Covey 08-16-2006 10:46 AM

RE: E-flite J-3 Cub 25 ARF
 
Since most On/Off switches only use 2 of the 3 wires, ground and switched plus, you can simply remove the signal wire pin from the ESC connector (that used to be plugged into the receiver throttle channel) and press-lock it into the open third position in the On/Off switch connector that now plugs into the receiver throttle channel. If you use an Exacto knife, you can gently pry up the lock tab on the ESC connector and pull out the wire with pin.

Some new On/Off switch designs on the market are now routing the third wire to make the process more plug-in-play easy.

COL J 08-17-2006 05:53 PM

RE: E-flite J-3 Cub 25 ARF
 
Greg,

Thanks for the info on the switch. It worked perfectly and is a needed safety valve.

Greg Covey 08-19-2006 07:29 AM

RE: E-flite J-3 Cub 25 ARF
 
1 Attachment(s)
The second of three videos has the J3 Cub 25 on floats taking off grass. We made the floats extra slippery by spraying Pledge furniture polish on the bottom. The Cub performed flawlessly. The power level and ground steering is proof that it will perform fantastic off water!

[link=http://www.gregcovey.com/reviews/EfliteJ3Cub25b.wmv]J3 Cub 25 Video 2[/link] (6meg)

Greg Covey 08-19-2006 04:43 PM

RE: E-flite J-3 Cub 25 ARF
 
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Here are some photos from our float testing off grass.

photos by "Papa Jeff" Ring

Silber_Igel 08-21-2006 07:11 AM

RE: E-flite J-3 Cub 25 ARF
 
[X(] Wild!!!!!! [:-]Weird!!!! [8D]Cool!!!!!

lthibault 08-28-2006 09:48 AM

RE: E-flite J-3 Cub 25 ARF
 
Hi,

very good review, seems to be a very easy kit. Thanks for all the valuable information.

I was aware of the ESC problem. I had a Multiplex Magister with an AXI motor and Eflight 40 AMP ESC. Once the floats were installed the plane gained some weight so the additional power required + the servos was too much. The ESC died while I was flying over a small lake. Needless to say, you loose total control and just cross your fingers...it went straight down, not a pretty site. Motor was still good though.

Two questions to you and the group:


1-I'm planning to use a Phoenix 35 AMP ESC, cut the BEC and use your setup to power the servos and receiver. Should I worry about the 5 AMP difference?

2-About some suggestion for a pilot & interior for this Cub?



lthibault 08-29-2006 01:29 PM

RE: E-flite J-3 Cub 25 ARF
 
OK, found the info. According to Castle Creation web site, the ESC can handle 45 AMP burst. Tech support from Horizon told me that the ESC needed to support 44 AMP with the EF Power25 Motor.


Greg Covey 08-29-2006 03:44 PM

RE: E-flite J-3 Cub 25 ARF
 
Hi Luc,

That's right. Typically, the ESCs are rated for continuous current and can burst to much higher power for 10-15 seconds or longer.

I was thinking about a pilot also so I may add something soon. We are in a holding pattern (so to speak) right now waiting for the weather and participants to all be available for the water take-off video. Hopefully it will happen soon.


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