john j

Ok so im new to the hobby. Bought my first plane the j3 cub brushless. It was amazing, for not ever flying a plane i thought i did pretty good. Anyway upon landing i nose dived into the ground causing the prop to break(no big deal) but when i put the new prop on it seems to have a little wobble. At full open the wobble goes away. what did i damage. do you think it will be alright for flight??

Thanks

John j

rcfury

My Feedback: (5)

I hate prop strikes, they always seem to ruin a great day of flying. Anyway, i think that propstrike you had caused the propshaft to bend a little. With the motor disconnected turn the propeller by hand and see if you see a noticable wobble. If you do you may need to pick up a new propshaft. Any LHS should have one avail.
Also that i may look at but, its really not that important is the prop could be out of balance which could be causing the wobble.

john j

Thanks for the reply. Can i still fly it??

rcfury

My Feedback: (5)

It all depends on what happened. If its the prop shaft that bent probably not. It may still turn but you may end up damaging something else. What plane do you have exactly?

john j

parkzone j3 cub brushless

LICobra

John

My J3 brushless had slight wobble right from the start, parkzone tech sent me another prop adapter (no change at all)....since the J3 brushless has no gear box, it's direct drive from the electric motor main shaft to the prop...with the prop adapter attaching to the main shaft. I posted photos in my gallery. take off the prop, then remove the cowl, loosen the set screw and the prop adapter come right off. if the main shaft wobbles ..replace the motor. hope this helps

Tony

john j

Thank you Tony. I went to the lhs and got a new engine shaft. Runs like a champ. How do you like you cub??

LICobra

John

I didn't know you could replace just the engine shaft. That's good to know, maybe mine is a little off and needs to be swaped out.... I really like the cub...it's an easy plane to fly and it's quiet...which is nice for the park I fly in. The only draw back I see is the lack of a tail wheel. From parking lot take off's and landings, the rear skid (part of the fuselage) is wearing down, so im going to remove the skid and install a tail wheel.

I have the PZ p-51 but I'll wait until I have a little more stick time on the cub before I try and fly that again !!

Tony

john j

Nice. i would also like to add a tail wheel and maybe 2" foam wheels. even in short grass it wants to act like a lawn mower!! That brushless is real fragile if the prop stops in the grass it will bend the shaft. i replace the shaft with an e flite 400, little bit longer but it works. Got 5 great flights in over christmas. let me know how you do that tailwheel im very interested.

LICobra

John...Christmas day I never got off the ground...my prop was a little worn by the parking lot take off's, as the tail lifts and the prop already has a downward angle ...it doesn't leave much room to play with..well I tried to get more speed for lift but the tail must have come up a little too much and I nicked the prop and it cracked...I just should have hand launched it !!...so I flew the 210 centurion since there was no wind...after Christmas diner and the relatives were gone I cut off the skid part of the fuselage and e-poxied the tail wheel on.

There are several tail wheels available...some steerable, some not...I chose non steerable which was the smallest and lightest...I didn't want to change the CG of the Cub. I used the Du-Bro RC Micro Tail Wheel Bracket, and the wheel is seperate. They also offer a steerable version...

Leo L

LI Cobra,

Nice tail wheel installation. The DuBro steerable unit is pretty nice. An alternative non-steerable is the replacement tail wheel assembly for the Aerobird3/Firebird Freedom/etc. : http://www.horizonhobby.com/Products...ProdID=HBZ2017 Just straighten out the wire loops and bend them away from the wheel. Insert these wire ends in the seam of the tail skid and epoxy in place.

LICobra

Leo

I actualluy bought both du-bro pieces, I used the non steerable because it was lighter, but I prpbably would have been better off with the steerable version, I guess only time will tell...as soon as I get another prop for the cub...the great thing about this hobby is there are a lot of options when it comes time to make some changes.

I did make an adjustment to the main landing gear to give the prop a bit more clearence as the tail lifts.

Huntermd14

LICobra, Are you a member of the Cobra's? I am, i do a lot of electric flying. What area do you mostly fly at?

Mike

john j

just ordered the dubro tailwheel assy and some super lite 2 1/4 inch front wheels for clearance. ill let yall know how it works out.

LICobra

Mike....No, I am not a member of the Cobra's, although I would like to join and fly at Bethpage park. I did visit the electric group that fly in Syosset but I hear from my recent visits to Willis Hobby that they only fly gliders now ???.... the Cobra's web page doesn't seem to show an application...any help with that... I live in Lindenhurst and fly at a local town park early in the morning. I use to fly gas powered planes 20 years ago with my x-father-in-law at cedar creek, so now im starting all over again with electric.

I am involved with long island cobra's car club, replica AC Cobra's.


John....let us know !!

Tony

LouJitsu82

I just recently purchased the J-3 Cub BL, On My first flight I was trying to adjust the rudder trim while flying too low, I nose dived hard from about 15' which broke my prop and bent the main shaft. My LHS told me I had to replace the whole motor:-( I tried using the e-flight outrunner main shaft but it seemed as if it was about 1/8" to 3/16 shorter & it had an extra groove/clip. I also had a hard time getting the outer part of the motor disconnected from the shaft. There appears to be 2 small set screws which i dont have the right size allen wrench for although i have a complete set of metric and SAE...So anyways i have a new motor coming, but if i can replace just the shaft that would be great! If you can give me a part # or any other purchasing info that would be awesome!

I was able to straighten the shaft fairly well and fly for 2 batteries yesterday before the wind picked up and it was such a blast!!!
Im a total newb so ive crashed a few times but this plane is very durable, I'm now on my 3rd prop. LOL. Anyone tried any other props than the stock one?

I havnt found any other threads for the brushless version of this plane other than this one. Thanks

john j

Lou i replaced the shaft with an eflite 400. it was about an 1/8 " longer but works fine. i do have a spare motor just in case, i am also a newb and have replaced 3 props and a wing so dont feel bad, just be glad the parts are available at almost any lhs. i got those 2 set screws out with a mini flat head that i ground down to fit.

LouJitsu82

Hey John,

How did the tailwheel/2-1/4 wheels install go? I already ordered another motor so i guess im not gonna worry about replacing the shaft on this motor. I just bent it back and it seems to be fairly forgiving.

I got some packaging tape and ran a strip all the way down the front edge of the wing & wrapped the edges (wing tore a little where the rubberband contacts it in the front) Also the rear post (rubberband hold-down) started to tear on the fuse so i did a superglue/wrap job on that. I tried hot glue but it didnt want to bond to the fuse too well.
I flew three batteries today and did pretty darn good. My landings were fairly smooth but i have a hard time ROG like the rest due to the rear skid.

I'd like to hear how the steerable tail wheel works out. Let me know how it goes.

-Lou

john j

I have not seen the ups man yet. should be here any day. Thats funny that your fuse ripped near the hold downs, mine did to, i used some 5 min epoxy an its stronger than ever!! glad to hear your flights went well, im about to head to the field now..

john j

2 1/4" dubro sl are awesome!! much better clearance in the short grass and she just wants to come to a smooth landing every time!! i have not had time to mess with the tail wheel yet, but it wont be long. in the process of buying a mini pulse for my 2nd plane at the moment

shawnkilpatrick

Hi all, I too have the Parkzone J3 Cub BL
I started on a Parkzone Super Decathlon and it was insanly hard to even get in the air... VERY under powered. I almost gave up all together before I tried my new Cub. This J3 Cub BL is how flying is supposed to be I think, a great rush when you take off and land and enjoyable air time!
Anywho, I am also a nube and have only completed a handfull of "successfull" flying experiences. haha. I have already tried a battery upgrade, I put an 11.1v 1000mah lipo in and boy did it scream!! However I have now run into a problem, if I throttle up slowly the motor will twitch back and forth and then stop and a loud siren noise screams out in an increasingly higher pitch! If I hammer down she takes off with no argument??? I have posted this queston on Wattflyer but no one seems to really know whats going on, best idea is that I am exceeding the 10A that the ESC is rated for.
Because of that problem with the 11.1v lipo I have been sticking to the stock 7.4v. I have had the best flights of my short flying lifetime so far! I have nosed into the ground once because the grass just trips the little wheels and she dives her nose into the ground. I have even snapped a prop on take off (was really cold outside).
I really want to know if anyone of you guys has a watt meter and if any of you have done some prop testing???? I want to know what prop I should use next. Seeing as I have already gone through 3.

sedne

Does your motor still scream after going back to the 7.4v batt? You should try putting some bigger tires on for grass strips. I have the PZ J-3 brushed version and I put on some 2 1/4" tires from Dubro, It made a huge difference.

shawnkilpatrick

Yeah I will put those tires on.... why did you go with the 2 1/4??? I am also going to try to rig up a sterrable tail wheel, i just dont want to rip my rudder off on a hard landing!

sedne

Initially the only reason I went with 2 1/4" was because they were all my lhs had at the time. I had to use larger dia. axle screws so the wheels wouldn't be wobbly. They really look good (I think) without being to big.

shawnkilpatrick

Ok well I just picked up a pair of Dubro Sport lite 2 1/2" wheels. They are massive! haha. To gether I think they are about 8g heavier than the stock ones. Since the whees are almost right under the COG I think it should be fine.... I hope. Oddly enough the axle hole on the new wheels looks like it is smaller than the axles on the plane, I guess I will just drill em out a bit.