I have been looking in this forum for a thread that talks about the $20 Hobby King J3 Old Timer. On the International side it is around $17 and just under $20 on the US side.

Anyone else built one of these. I just finished my first build with one of these and haven't even flown it. I hope to get out this weekend and try and fly it.

I will take some pics to post before I take it for it's maiden flight but wanted to see what others had done with the plane or what there experience was.


http://www.hobbyking.com/hobbyking/s...imer_ARF_.html


The cost of this plane was much less than the cost of parts for my Flyzone RTF, assuming you have the servo's, ESC, motor, and receiver.

I would love to hear about others experience or mod's.

Thanks.

I have had one flight on this plane and found it was very tail heavy. It kept going up and up and... had to fight to get it back on the ground.

I went back to the forums and found most people have this same issue. with this model. It seems it was designed to have an older heavier brushed motor in it so when you put a brushless motor in it the tail is too heavy.

I think for a $20 kit this is a heck of a deal.

I have a brushless set up from the gamma 370. Not sure what the kv is but have used it in a scratch build of twice the size and weight, so it should be plenty for this plane. There is a new vid on one set up with a floater jet power plant and a 6x4. music is awesome on this vid!

J3 Cub EP Old Timer RC Plane (4 min 0 sec)

I have a floater jet and it is ,kind of, fast. (40-50 mph ish). On 3 cell, I would think it to be too hot a set up for this plane? I also have the brushed motor and esc out of my wild hawk, but not sure if the esc has fail safes for lipo? This plane seems to be getting a small fallowing, but havnt found a ton of info on it like some other threads/planes. But it might be fun to put the knowledge i have gained from rc groups to work and figure out a set up for my self. Did you find a happy cg yet? Weather supposed to be bad this weekend, so the build will begin. Will post some pics and vids as they happen.

will be starting j3 build today!

My build really only took a day or so. I hadn't built one before so there were some lessons learned.

I had a hard time getting the length of the push rod like I wanted. Maybe I am doing it wrong but the push rods seemed a little long. Even when I adjusted the end to the top of the range the servos were not completely centered like I would like them to be.

I may end up replacing them with push rods and horns that have a screw clamp that connects to the horn. That should make the set up and centering of the servos easier.

I used the receiver that came with my Turnigy 9x but may replace that one in the future with an OrangeRX R615. I bought the Orange DSM2 module so may end up swapping out the receiver.

Didnt start the build this weekend........We had a pretty good snow sat and had to take the inlaws to airport, that took about 3 hours. Had to do some snow removal , that took a couple of hrs..........Played with airbrush a little and that was it.
thinking of trying the new orange rx/gyro on this plane ? Still havnt decided for sur on motor combo...... and have had offers from others to buy the plane.

This late season snows and bad weather is making it rough for every one.

Even though I had the CG all wrong the plane was stable it just kept climbing up.

Here are the parts I have used:
Motor: D2826-10 1400kv Brushless Motor
ESC: Turnigy AE-25A Brushless ESC
Servos: HKSCM9-5 Single Chip Digital Servo

The motor and ESC can be used with either a 2s or 3s battery. Right now I have a 2s battery connected but once I am comfortable I will get a 3s battery.

what size prop r u running? I have a little 2212 1000-1200 kv (dont remember exact specs) that i used in a scratch build plane. I ran an 8x6 on the scratch build plane, that was about twice the size of this thing, and it had enough for an old timer type plane. thats probably the set i will go with. I do have a brushed set up that would bolt right up. The esc even has the on/off switch and safety button that would mount right into the holes on the side of the fuse. But it might be a little under powered. It was the set up that came stock in the wild hawk, and it was barely enough for that plane to fly. Not in too big a hurry. I bought this for the price and to put some spare electronics to work........ A couple of guys that fly at the field with me have some smaller scale planes and it will be fun to have something in the same category to huck with them. My go to plane is the floater jet. Its fast and super huckable. The j-3 will be my back up and/or a change of pace.

I am using the prop recommended on the specs for the motor. I am using a 2s battery at the moment and the 9X4.7 prop.

Suggested Prop: 7x4(3S) ~ 9x4.7 (2S)

I do plan on moving to a 3S battery at some time and will switch props then.

OK a quick note... this plane does not like to do a loop when using the 9x4.7 prop and the 2s battery.

I flew 4 batteries through it and it was stable and I think a good trainer. I had added weight to the nose but still not enough I think. it had a tendency to rise.

After flying around and enjoying that I got a little confident and tried a loop the loop. It didn't quite make it over the top and I over corrected on the way down and augered it into the ground.

I had done it once before and got it going but this time it didn't work. I will post pictures tonight....

I got the sevos and electronics in this week end. just havnt locked everything down yet. Not sure what batt i will be running yet, so may have to move things around a bit to get cg. i used screws to mount the motr to the existing mount and doesnt rub. Its a 1250 kv on a 8x6 prop. ...seems to have plenty of static thrust. I hooked it up to a 3 cell and it was , probably, too much. What size batt r u running and still not getting the cg you want? did you build some down thrust for your motor? the bigger the prop you run the more it will want to climb and have issues with tourge and thrust angles. how did the plane hold up as a post hole digger? I will get some pics of mine up soon.

Originally Posted by banknwank

I got the sevos and electronics in this week end. just havnt locked everything down yet. Not sure what batt i will be running yet, so may have to move things around a bit to get cg. i used screws to mount the motr to the existing mount and doesnt rub. Its a 1250 kv on a 8x6 prop. ...seems to have plenty of static thrust. I hooked it up to a 3 cell and it was , probably, too much. What size batt r u running and still not getting the cg you want? did you build some down thrust for your motor? the bigger the prop you run the more it will want to climb and have issues with tourge and thrust angles. how did the plane hold up as a post hole digger? I will get some pics of mine up soon.

I used the existing motor mount but made a plywood adapter plate and standoff's to get the prop on the outside of the cowl.

I have ordered a replacement plane and a new motor. I am sure the current motor is fine but I want to try a faster motor. The motor I ordered is the same size but faster.I will use a smaller prop with it as well. My plan is to rebuild it as the same but then replace the motor after I get used to it to see what that will do.

For batteries I was using a 2s 500mah and an 800mah. I had the 800 in there when it crashed.

It could very well be the prop that was pushing it up. It seemed to go up when I hit the throttle.

The majority of the plane is intact but the front is crushed. I hit pretty hard. I was trying to loop and it didn't have the power/momentum to take it back over the top. It rolled out at the top and I spun the stick the wrong way and it spiraled down. I was too close to the ground to recover it in time.

Bummer, I liked the plan and it was the first one I have built. Got a new kit on the way and will shift the components over when it gets here.

The biggest change I will make on this one is the control horns and control rods. I want to have one with a clamp on the control horn so I can easily adjust the control rods.

I am not sure if the foam on these planes will respond , or not....... but i have had great success getting accordion damage out of fuse buy boiling them. I would suggest you try to repair the crashed plane as many times as possible. Try to learn as much as you can from it before you scrap it for the new one. That being said, you can get the new kit for what a wing would cost you for any other plane!

I have an 800 2 cell i will try to go with as well. It seems just a little light for tuning cg, but thats what i have. your old motor was a 1400 kv correct? If you start pushing up the kv, your prop will shrink and pitch speed will go up......... this plane is meant to be a cruiser, and i would think slow fly prop/motor set ups would be prudent. Learn to keep this plane alive for a while,(glue, tape,epoxy.....) then get something sportier when you are ready. I havnt been flying very long, but cubs with the prop up front are not the easiest to learn with. I learned with pusher/gliders that are a bit more forgiving in less than perfect landings and easier to repair.

The foam is fairly dense and rigid so it came apart in pieces. I can try to put it together like a jigsaw while I wait for the new plane to come in.One of the reasons I purchased the plane was the low cost.

You are probably right about it being a cruiser. It is a trainer with only rudder controls so it makes sense that is what it would do. I have heard about others cutting out the ailerons on the plane and using them. I may do that once I am comfortable with the flight characteristics of cruising.

Need to practice my landings as well. May try taking the gear off and sliding it across the grass when landing.

maybe the added weight of the repairs will get your cg correct? I would just try to learn as much as possible from your throw away plane. then, use what you have learned on your new plane build.