Greg Covey

Hi,

I'm reviewing the [link=http://parkzone.com/]ParkZone[/link] J-3 Cub.

ParkZoneâ„¢ Charge-and-Flyâ„¢ park flyers come ready to fly. Everything you need to enjoy a hobby-quality park flying experience is in a single box, including the batteries. No gluing. No painting. No hassles. In as little time as it takes to charge a battery pack, about 40 minutes, you're airborne.

The ParkZoneâ„¢ [link=http://parkzone.com/Products/Detail.aspx?ProdNumber=PKZ1100]J-3 Cub[/link] combines the classic lines and gentle flying manners of its legendary namesake for a superb park flying experience. Getting airborne is as easy as it gets. Mode Change Flight Controlâ„¢ software couples elevator and rudder for newer pilots, so they can smoothly adjust to using pitch. More experienced flyers can enjoy fully independent elevator and rudder control with a quick mode change.

The J-3 Cub is meant for intermediate level pilots that have already mastered a trainer. The Cub features a one-piece wing, 370 motor with gear reduction and aluminum landing gear with foam wheels.

Here is how it comes in the box:

Specifications:
[ul][*] Wing Span: 37.25 in (950mm)[*] Overall Length: 26.75 in (680mm)[*] Flying Weight: 15 oz (425 g)[*] Motor Size: 370 power w/gearbox[*] Radio: 3 proportional channels[*] Speed Control : Power FET proportional ESC receiver[*] Recommended Battery: 8.4V 600mAh Ni-MH[*] X-Port: No
[/ul]

Greg Covey

Out of the box, you can see there are very few parts. The J-3 Cub comes complete with a 3-channel transmitter, batteries, and even a DC Peak Charger!

The 7-cell, 600mAh NiMH pack must be charged first before flying. The 8-AA cell batteries get installed into the transmitter case.

Greg Covey

Only the landing gear and wing struts need to be assembled. It is that easy!

The wing is held to the fuselage top by four rubber bands and strengthened by the struts secured to the fuselage bottom.

Greg Covey

The linkages are already connected and I found the stock settings for minimum throw range to be very adequate when flying.

Greg Covey

My J-3 Cub was ready to fly in no time at all.

wattman

Adding to Greg Covey 's review

Pictures of under the cowl of the cub showing the motor and gearbox

Greg Covey

Dennis,

Thanks for the inside photos of the cowl. I haven't taken mine off since there was no need.

Apparently, the gearbox screws came loose on his plane just before take-off.

How many flights did you have on your Cub before this happened?

Greg Covey

I flew the maiden voyage of my J-3 Cub without any issues. I needed only to add some down trim as it kept on climbing. The linkage settings on the outside hole of the control horns provided plenty of authority.

I was surprised at both the stock power level and flight duration. For a RTF plane right out of the box, I was very happy!

I had no problems using the default factory flying mode where it applies slight up elevator on your turns. When flying the J-3 Cub scale, this is most appropriate for a rudder-elevator high-wing plane.

Most of my flight time was spent at half-throttle which lasted at least 10 minutes, if not longer.

wattman

It was to be the 5th flight , when the motor ran with no shaft turning . [X(] The 2 screws holding the motor to the gearcase came out , and were contained in the gear housing . Easy to re install and back in service .
I now have 8 flights logged in , I have a inexpensive cook timer from housewares at Wal Mart that I set for 11 minutes and when it alarms , start setting up for a landing , no hurry . I do not know yet how long till the battery drops voltage and the motor shuts off ?
I find it climbs a lot at full throttle , most of the time I am at half throttle flying , I will keep increaseing the time setting on my timer , till I find out when the motor shuts down .
Did I say how much I really like the airplane ? So much fun for the money

Greg Covey

Sounds good, Dennis.

It has been reported elsewhere that the stock prop is an 8x4 with a 2mm shaft.

Here are some close-up flying shots.

wattman

Oh I like those photo's , I used the top one for my computer wallpaper , thanks

jbflier

Hi Greg; I have flown r/c for 45+ years,(the last 6-7 years 28% scale gas). I recently bought the Parkzone Cub to have fun with my grand kids and am glad I read your review, as I have a few questions about the motor area. While test running 1 of three batteries, I noticed alot of play on the prop shaft. While looking at your photos, I notice there is a nylon looking spacer between the last nut on the prop shaft and the gear cover. I only have 2 thin metal washers, which are obviously causing the slop. How long is the nylon spacer on your gear shaft, as I will fix this before I fly? Also, the motor/gear cover in your photo looks like it fits flush to the firewall, where mine is against the two top pegs, and causing a large degree of downthrust. Is all of this downthrust correct? While all of this is off, did you lube the gears with anything? Thanks in advance..........[8D]

jbflier

I quess my last post/questions was actually responding to wattman. Anyhow all help is greatly appreciated.............

Greg Covey

Hi John,

The downthrust is normal and the gearbox slop may be normal as well.

When the pinion gear and spur gear are dissimilar materials, lubrication is not neccesary. It looks like they still lubricated the gears anyway.

jbflier

Hi Greg; Thanks for the prompt reply. I'm not totally new to electric motors, as I've raced cars for years also, but I just want to make sure all is correct for the first outing. I did put a nylon spacer between the last nut to tighten things up. There is now aprox. 1/32" movement on the prop shaft compared to aprox 3/16" before. I'm running the motor now and it sounds much better/smoother. I'm getting around 7-8 minutes run time on the batteries. Does that seem to be about right? Thanks again for any/all help with this...........

Greg Covey

John,

You'll get longer flights in the air. Keep in mind that your static ground tests should only be 10-20 seconds long or the motor may overheat due to lack of forced air cooling. This is a big conceptual difference between electric and glow power testing. Static ground testing on electric motors is meant for short term to measure current only.

To measure flight pack capacity, you must use a capable peak charger with that feature built into it.

Greg Covey

Here is a video I shot for my review of the J-3 Cub. You can see my advanced lip technique to turn on the throttle before tossing it.


[link=http://www.gregcovey.com/RCU2/J3Cub.wmv]Hi-res video[/link] (10meg)

[link=http://www.gregcovey.com/RCU2/J3Cub2.wmv]Med-res video[/link] (3meg)

dribbe

Nice video Greg! Thanks for the review.
David

wattman

2 more great flights logged in , had my timer set for 12 minutes , and then land , still have battery left , will keep increaseing timer setting . I made a mistake tonight , after the last landing at the field tonight , I thought I had loaded everything as usual , well I am home , 3 hours later , and a beeping alarm went off and continued beeping .............it was the Parkzone xmtr , the red light on it was flashing and it was beeping .........[X(] ............,I had left the xmtr turned on [].
So I have learned there is alarm if the xmtr is left on , low voltage I suppose , will have to change the battery's , after being left on for 3 hours , I would not want to risk flying with the batterys . Live and learn

jbflier

Thanks to Greg & Wattman; You learn something new every day; I wasn't aware of the short static thrust testing or that the Tx had a beeper in it...........

Greg Covey

John,

I forgot to mention also that you get about 10% - 15% unloading in the air, even at maximum throttle so the static testing is really worst case but we use it to determine the appropriate motor loading.

RC Sumo

The newer Aerobird challenger XMTR's also have a beeping alarm in them. Bad sound to hear when you are 100ft up and and a good 500ft away![X(]

jbflier

I went out this a.m. and got three nice flights on my plane. I have to admit I was a little concerned about the amount of downthrust on the motor,but..........all was well. It actually wanted to climb, so adjustments were made. It's a very nice flying airplane.

Greg Covey

Good job, John.

I usually trim these type of models for half speed or "cruising" speed. If you have the automatic flight control feature enabled, that can attribute to some climb when you are turning.

tramsay

Hi there Greg,
I am new to RC flying, and I was wondering if you could answer a few questions for me.

1. In the video your Cub seemed very responsive. Did you adjust the throw on the servos? or did you leave that all factory set? My cub is not nearly as responsive as seen in the video.
2. Is it alright to fly with a slightly bent prop shaft? I have bent so many badly, but I have also bent a few only slightly, and was not sure if I might be able to still use those.
3.What is the best way to trim a plane? My cub always wants to go to the right...no matter what I do. It also seems to slowly turn to the left and quickly turn to the right? Is there something I can do to remedy?
4....and finally, How the heck do you do a loop? and a roll? Every time I try one I get vertical and then stall. Thankfully I have been flying long enough to have the self control to let the plane right itself when it does that...but I can figure out how to actually get it to roll or loop.

Thanks Greg!