Parkzone J3 Cub BL
#76
New Member
Join Date: Jul 2009
Posts: 10

Have flown my J-3 Cub six times. I crashed on five, and crash landed on the sixth. Have bought replacement parts and rebuilt my plane. Was not sure of proper location of the receiver so I tied it to the back side of the battery compartment. In a balance test it seemed to be level above the back of the landing gear support. But in hand launching it seemed to make the thing nose heavy. Next, I implanted a weight aft of the servos. It balanced about at the strut screws on the bottom of the fuselage. When it took off it climbed like a bat out of hell, and wanted to keep climbing. I guess I over did it. Thought I was going to break the altitude record, but this turned out to be a blessing. I learned to fly, including recovery from two stalls. So how does one find the best CG for the J-3?
#77
Member
Thread Starter
Join Date: Nov 2007
Posts: 81

Generally the rule of thumb tends to be 1/3 of the width of the wing back from the leading edge of the wing... What I mean is your plane should be level if you hold up you plane with your fingers under the wing about an inch and a half back from the front edge.
Hope that helps!
Hope that helps!
#78
Member
Thread Starter
Join Date: Nov 2007
Posts: 81

Hey guys, you will be interested to here the numbers I got lastnight with my watts up meter...
Heres the nitty gritty:
3cell 900mah 25C battery (22.5A continuous acceptable)
10A e-flight pro ECS (10A con, 12A peak 15sec)
Parkzone stock 370 BL outrunner 1500kv
Stock prop (I think it is an 8.5x5.5)
Ok and here are the numbers from the watts up meter:
Ap - 14.01
Wp - 156.04
The rest I have written down at home, I do remember at half throttle the Amps were only at apx 2A-4A
Thats a whole lot of watts for a 15ounce parky!
What do you guys think... should I try some different prop arrangements or get a larger ESC?
I was thinking of getting the 36A ThunderBird ESC from castle... LHS has them for $59 can...
Heres the nitty gritty:
3cell 900mah 25C battery (22.5A continuous acceptable)
10A e-flight pro ECS (10A con, 12A peak 15sec)
Parkzone stock 370 BL outrunner 1500kv
Stock prop (I think it is an 8.5x5.5)
Ok and here are the numbers from the watts up meter:
Ap - 14.01
Wp - 156.04
The rest I have written down at home, I do remember at half throttle the Amps were only at apx 2A-4A
Thats a whole lot of watts for a 15ounce parky!
What do you guys think... should I try some different prop arrangements or get a larger ESC?
I was thinking of getting the 36A ThunderBird ESC from castle... LHS has them for $59 can...
#84

My poor j-3 finally bought it one foggy day and I moved on to the Trojan.
GRU
#85
Member
Thread Starter
Join Date: Nov 2007
Posts: 81
#86
Member
Thread Starter
Join Date: Nov 2007
Posts: 81
#87
#89

Sure. By the time this pic was taken I had already modified the powertrain to run a Thunderpower 3S 910mAh battery with a Common Sense outrunner (I forget the size - its still outside somewhere in my 'motors bin' lol). To fit the battery I had to widen the battery holder, and when I did this it made the battery door pretty much useless without a little 'help' from a piece of velcro across it when it was closed.
There ya go.
GRU
#90
Member
Thread Starter
Join Date: Nov 2007
Posts: 81

Shawn
#91
Member
Thread Starter
Join Date: Nov 2007
Posts: 81

Well it finally happened! My stock 370 BL died. It melted itself out of the holder. I think it got a little dinged up to the point where magnets where making contact and thus heat.
I just put an order in to zebrahobby.ca (based out of calgary) for one of there zebra motors... only $25 so I hope it does the trick. Anyone else order anything from zebrahobby.ca?
Shawn
I just put an order in to zebrahobby.ca (based out of calgary) for one of there zebra motors... only $25 so I hope it does the trick. Anyone else order anything from zebrahobby.ca?
Shawn
#92
Newb
Join Date: Jul 2009
Location: Land of sunstroke
Posts: 9

i have been looking at the emax 2208/2218 on ebay for 11 bucks shipped as a replacement since by friend hosed his motor *epoxied together*. I think he will only get one more crash on it before its toast. in his case, that means one more flight

#95
Newb
Join Date: Jul 2009
Location: Land of sunstroke
Posts: 9


#96

I have just purchased the J 3 Cub2 days ago and have not flown it yet. Been too windy so far here on the beautiful west coast of Iowa! Being a complete noob I have had some limited sucess with micro heli's and a cx2,mcx, working on skifully crashing the 4#3B Walkera! I also have a Beechcraft Staggerwing flown and crashed once. Could someone please point out the most important mod for the J 3 ? If (when) I crash I want the survivability with out much parts cost that I can make. Any Info appreciated thanks in advance.
#97
Member
Thread Starter
Join Date: Nov 2007
Posts: 81

Welcome to the thread gofer, I think you have made a wise choice with the cub for starting out! It happend to be my second plane (first one was LAME)! Did you get the brushless model??
First off this model is great out of the box! You really should try to fly it as much as you can before you start moding. Just wait for a calm day and she is a real breeze to fly!
Alright, Mods... One thing you need to be aware of is before you start to put any money into mods for her is that the radio has a tendancy to loose signal. That said I would recomend a new radio, one that you could use down the road too. I upgraded to the Spektrum DX5e for $100 (TX and RX). Some less exspensive and very helpful mods include: larger landing gear, reinforce the inner framework with strofoam, different props. Other than that you could get a 3 cell lipo for mudch more power but when you go down that road you have to repace other parts like the ESC and motor as well.
Hope that helps!
Shawn
First off this model is great out of the box! You really should try to fly it as much as you can before you start moding. Just wait for a calm day and she is a real breeze to fly!
Alright, Mods... One thing you need to be aware of is before you start to put any money into mods for her is that the radio has a tendancy to loose signal. That said I would recomend a new radio, one that you could use down the road too. I upgraded to the Spektrum DX5e for $100 (TX and RX). Some less exspensive and very helpful mods include: larger landing gear, reinforce the inner framework with strofoam, different props. Other than that you could get a 3 cell lipo for mudch more power but when you go down that road you have to repace other parts like the ESC and motor as well.
Hope that helps!
Shawn
#98
Member
Join Date: May 2008
Location: Peterborough,Ontario,Canada
Posts: 262

Heres my supped up Cub with all the electronics from the Spitfire. It flies well and it almost crashed into a wall upon landing!!
[media]http://www.youtube.com/watch?v=R7UC2nO-0U4[/media]
My girlfriend is filming using her cheap digital camera that wont let you zoom in or out!! You may need to watch in full screen!!
[media]http://www.youtube.com/watch?v=R7UC2nO-0U4[/media]
My girlfriend is filming using her cheap digital camera that wont let you zoom in or out!! You may need to watch in full screen!!
#100
Member
Join Date: May 2008
Location: Peterborough,Ontario,Canada
Posts: 262

ParkZones Corsair Maiden Flight!!
Thats a sweet plane also!!
