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Parkzone J3 Cub BL

Old 07-09-2009, 02:33 AM
  #76  
hungryjoe56
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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?
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Old 07-09-2009, 04:12 PM
  #77  
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Originally Posted by hungryjoe56 View Post
So how does one find the best CG for the J-3?
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!
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Old 07-09-2009, 04:12 PM
  #78  
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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...
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Old 07-10-2009, 03:59 PM
  #79  
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Hi all,

I picked up the e-flight 30A ESC w/switching BEC, and tried aa APC 9x4E prop. Now I am getting about 13.7Ap and 150Wp... i guess its getting better...
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Old 07-13-2009, 07:59 PM
  #80  
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So does anyone else have a J3-Cub out there and looking to make any improvements, if so we can help!

Shawn
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Old 07-13-2009, 08:37 PM
  #81  
hungryjoe56
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"So how does one find the best CG for the J-3?"

Shawn:

Thank you for the answer to my question. You explained things clearly. I appreciate it.

Hungryjoe56
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Old 07-14-2009, 08:00 PM
  #82  
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Im glad to be of help.

You can check the trim as well... you may be nosing down when you hand throw?

Shawn
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Old 07-16-2009, 04:04 PM
  #83  
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So can anyone tell me if they have done any mods to their Cub? Any Alerons, tail wheel or anything else cool??

Shawn
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Old 07-16-2009, 04:40 PM
  #84  
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Originally Posted by shawnkilpatrick View Post
So can anyone tell me if they have done any mods to their Cub? Any Alerons, tail wheel or anything else cool??

Shawn
Yeah, I think I pretty much did everything possible. Its back in the thread in fact.



My poor j-3 finally bought it one foggy day and I moved on to the Trojan.

GRU
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Old 07-16-2009, 06:24 PM
  #85  
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Originally Posted by Crash&Burn(Often) View Post
The only other thing you might want to do is put velcro on the wing struts. Any G-loading on the airplane will rip the little screws that hold the struts down right off.
What do you mean by putting velcro on the wing struts?? I dont quite understand?

Shawn
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Old 07-16-2009, 06:33 PM
  #86  
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Originally Posted by groundrushesup View Post
My poor j-3 finally bought it one foggy day and I moved on to the Trojan.
Yeah thats too bad! I really like the Cub but am really getting eager to start flying with alerons. I figure the T-28 PNP will be my next one. You like it??

Shawn
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Old 07-16-2009, 10:23 PM
  #87  
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Originally Posted by shawnkilpatrick View Post
Yeah thats too bad! I really like the Cub but am really getting eager to start flying with alerons. I figure the T-28 PNP will be my next one. You like it??

Shawn

You'll never look back, mate.
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Old 07-17-2009, 11:05 PM
  #88  
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Hey GRU, do you think you could explane to me the purpose of putting velcro on the plane? I didnt understand what the dear was??

Shawn
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Old 07-18-2009, 06:52 AM
  #89  
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Originally Posted by shawnkilpatrick View Post
Hey GRU, do you think you could explane to me the purpose of putting velcro on the plane? I didnt understand what the dear was??

Shawn

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
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Old 07-18-2009, 07:28 PM
  #90  
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Originally Posted by groundrushesup View Post
...a little 'help' from a piece of velcro across it when it was closed.
Oh ok I see... you just made a velcro door essentially! Do you have any pictures of how you put the battery in there? I am curious, I just rebuilt the inside of my Cub with Styrofoam and I now have to put the batteries in through the top everytime.

Shawn
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Old 07-18-2009, 11:43 PM
  #91  
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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
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Old 07-19-2009, 12:21 AM
  #92  
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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
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Old 07-19-2009, 01:35 AM
  #93  
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buncha pictures from earlier in this thread in this post - you can see how extensive my rebuild was.
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Old 07-19-2009, 03:04 AM
  #94  
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Great thanks GRU.

Meepers let me know how the replacement works... I will post when I get my new one installed.
Shawn
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Old 07-19-2009, 04:56 AM
  #95  
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Originally Posted by shawnkilpatrick View Post
Great thanks GRU.

Meepers let me know how the replacement works... I will post when I get my new one installed.
Shawn
I will do! I plan on doing quite a bit of trial and error, and its even better when someone else pays for it on their stuff so I know what to expect on my own!
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Old 07-21-2009, 02:52 AM
  #96  
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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.
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Old 07-21-2009, 03:41 PM
  #97  
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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
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Old 07-21-2009, 03:42 PM
  #98  
Lancifer
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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!!
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Old 07-21-2009, 03:54 PM
  #99  
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Haha that was close! Looks like she goes quite a bit faster. Does it handle well at those speeds? I am guessing the spitfire had a 480BL in it... what prop is on there?

Shawn
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Old 07-21-2009, 03:58 PM
  #100  
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Originally Posted by shawnkilpatrick View Post
Haha that was close! Looks like she goes quite a bit faster. Does it handle well at those speeds? I am guessing the spitfire had a 480BL in it... what prop is on there?

Shawn
It goes pretty quick and im just using the brushed 480 but its still quick and im using the 11x8 Spitfire prop. I had to wire the battery to the bottom since it was way to big for the battery chamber. You should check out my other bvideo of me maidening my PZ Corsair...
ParkZones Corsair Maiden Flight!!
Thats a sweet plane also!!
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