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Hobby King J3 Cub Laser Kit build

Old 08-19-2013, 08:33 AM
  #51  
solentlife
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OK ... I searched through my "it may come in handy one day bins" and found :



Fishing trace and a few crimps left ... a short piece of black plastic tube ...

I accept that the bungee part is nowhere near as bulky as the real -= but do I want all that drag ? So I elected for near cosmetic effect rather than scale bungee ..



The trick was to find a way to lock the top of the wire to the front leg at fuselage ... so a double wrap was made.



Then down to wire rods joint near wheels ... making sure I had plastic tube and crimps already threaded on ..



Short pieces of toothpick pushed into tube ends secured in place on the trace wire while I then dropped a bit of CA in to lock.



A small piece of black insulatinbg tape folded and scrunched up at the crossover completes the effect.

I think it's passable ?

Nigel
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Old 08-19-2013, 03:47 PM
  #52  
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Tried various to get the strut covering to sort ... but it was a difficult job.

With iron on film - it kept crinkling at near to fuselage as it had nothing to hold to. So in the end I bound the struts with yellow tape across the V creating a base surface ... then iron on film ... this seemed to work better - still not perfect but at least it gives reasonable result. Only other way I could imagine is to infill with foam sheet and cover that ?



Nigel
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Old 08-19-2013, 05:15 PM
  #53  
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The window glazing annoys me and niggles me to sort a better way.

The problem stems from the framework not being flush to fit the acetate. Some are formers inside the fuselage line - others are flush with outer fuselage sides ...

I wonder if I can glue cap strips so I can then cut each window to fit the strips - glueing from inside .... Then I could also cover the caps with yellow film to frame in.

Not an easy job .. but would be better than the way at present.

When I have a real crap weather day .. will have another look at it.


Nigel
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Old 08-19-2013, 06:16 PM
  #54  
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Originally Posted by solentlife View Post
The window glazing annoys me and niggles me to sort a better way.

The problem stems from the framework not being flush to fit the acetate. Some are formers inside the fuselage line - others are flush with outer fuselage sides ...

I wonder if I can glue cap strips so I can then cut each window to fit the strips - glueing from inside .... Then I could also cover the caps with yellow film to frame in.

Not an easy job .. but would be better than the way at present.

When I have a real crap weather day .. will have another look at it.


Nigel
I try to frame all of mine that way if i can get away with it so i dont have to use striping tape later to cover up the glue around the edges. I was using RC 56 canopy glue but i found that locktight stick + seal ,it is thicker than rc 56 so it wont run and a very little on both sides press together once and its done. It also drys clear and cleans up with soap and water.
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Old 08-19-2013, 06:30 PM
  #55  
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Final details ..

AUW not incl LiPo : 650 gr

Motor : Turnigy D2826-10 1400kv
ESC : 25A HK - I may increase this later as I think she is a little warm after testing...
7x5 prop - draws 18.5A
7x6 prop - draws 19.2A
(on 1800 3S 25C LiPo)

Flying weight with LiPo 3s 1800 25C would be 780 gr.

Nigel
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Old 08-20-2013, 01:55 AM
  #56  
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Looks much better. I can see now that you did not worry about having flex in your gear leg wires. Gives you a lot more options for faking the bungee system. I think I would have used CF rods and pieces of foam to replicate the whole construct.
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Old 08-20-2013, 08:35 AM
  #57  
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Originally Posted by maxflyer View Post
Looks much better. I can see now that you did not worry about having flex in your gear leg wires. Gives you a lot more options for faking the bungee system. I think I would have used CF rods and pieces of foam to replicate the whole construct.
The trace wire in fact stiffens that lot up considerably ... It would be as stiff as you using CF. The trace wire is 50lb nylon coated steel. The crimps are the matching ones so designed for same load.
The wire legs are 2.2mm bicycle spokes ... so not so weak themselves.

I used same for the rigging on my Scale Competition Neiuport 28 back in 80's ...

Anyway - have to agree that she looks the part now.

Thinking of looks ... I found a few pictures of what was called the FITFIRE ... in 1940 ... in USA, Piper (Taylor) donated a number of J3's to RAF for Fundraising in USA... they were decked out in RAF scheme with roundels etc. They were displayed around USA under the RAF Benevolent Fund banner ... to raise funds for UK to continue it's lone fight against the Nazis. It was dubbed the FITFIRE.
Wish I'd seen it earlier !! I may have copied it onto my model.

Nigel
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Old 08-20-2013, 12:36 PM
  #58  
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mmmmm not so goood maiden ....

Decided that today was the day ... checked all at home .. went to gravel road site ... too many stones and holes in gravel road ... so went to secondary rough field where we have a conveyor belt runway...

Gave her a second check over ... tried controls ... set her down on runway ....

All seemed fine ... opened throttle ... away she went, left ground, banked left and went in.
Split the thin cowl, broke engine mount blocks.

Picked her up and boy am I stupid !! I had noticed other day that left aileron was touch up compared to right .. I though I'd corrected it ... but once I got back to car ... there it was staring me in face !!

New motor block ... epoxy now setting.

Cowl has reinforcing tape inside ....

She will be ready to go again - this time with ailerons sorted !!

It wasn't my day today as I then decided to fly my SE5 ... that lifted, banked right and cartwheeeled ripping of an aileron !

OK ... so today is not so good ... I fire up my Mini4 ... 3 mins into flight - she decides enough and spins in - luckily with no real speed ...

I decide to go home !!

Nigel
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Old 08-20-2013, 05:20 PM
  #59  
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SUCCESS ... repaired ... reset ailerons ... back to field ....

Video being sorted at this moment.

She flew well ... very light for that big wing. She floats on ... stall is straight and nose down. Think that may be more to carrying the 2200 lipo .. I decided to put the heavy in - get CoG at foremost point and safe.

She needed bootfulls of UP trim ... but once trimmed ... she's a peach.

Definitely needs to be a bit heavier for my liking though as like this she will be only a calm / light airs flyer.

But all in all ... looks good in the air and the power train I picked is more than enough ...

Flight 6 mins exact ... 49% of the 2200 LiPo used.

Next will be videoi uploaded of the crash maiden and then the successful flight just after ...

Nigel
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Old 08-20-2013, 09:07 PM
  #60  
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Congrats!
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Old 08-20-2013, 11:03 PM
  #61  
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Great It worked out!!
Waiting on the video's!

Regards
Jimmy
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Old 08-21-2013, 10:29 AM
  #62  
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Not one to hide my mistakes .... here's my stupid first attempt.

[media]http://www.youtube.com/watch?v=Oyny5F9WhFg&feature=youtu.be[/media]

Basically - when I set her up - I had noticed a left bias in the ailerons. I thought I'd adjusted then - but must have put her down and forgot.

My field checks didn't eyeball the surface line-ups - only control actions so never noticed my mistake.

She had no option but to teach me a lesson and flip to the left ! Luckily she bounced well and airframe itself was undamaged. But she broke one of the engine mount blocks and split the thin plastic cowl.
I'm actually glad she broke the mount - as that may have prevented greater damage. Better to replace a block than rebuild !!
Motor shaft has a VERY slight bend now .... yes I know ... I have to replace it - I have spare shafts .... but it's good enough to fly for a few trimming / set-up flights ....

Next will be the video of successful maiden ...

Nigel
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Old 08-21-2013, 01:31 PM
  #63  
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Here's her successful maiden ....

[media]http://www.youtube.com/watch?v=nVtpF0cEoX8&feature=youtu.be[/media]

She was cross-wind on take-off and not knowing well enough her rudder authority - let her yaw ... fine.

She really is well powered but a little too light for the wing area I think. She floats on and on ...

The 2200 puts the CoG about as far fwd as you would want but she is so safe there ...

Overall ? Pain to build - but once in the air - she really looks the part and flies very well. For $24 + extras ... it's got to be worth it !

Nigel
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Old 08-24-2013, 06:31 PM
  #64  
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Drove 2 hrs across country to fly at another venue today ... and took the Cub. Wind was expected to be moderate - but I thought inland may be better.

Last flight of day - I decided to give her a go ... and she braved blustery winds to do quite well.

I was the idiot ! On take-off, the wind was swinging about and I injected a bootfull of right rudder ... she took off and I plain forgot left stick was over and she cavorted about with me fighting via ailerons to get her straightened up !! Realised right rudder was still on ... released it and away she went clean ... Boy was I lucky not to crash ! Literally brain fade !

Video to be uploaded once edited ...

Nigel
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Old 08-25-2013, 10:36 AM
  #65  
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Saldus 24 Aug 2013 ....

[media]http://www.youtube.com/watch?v=xHBADkWhd-g&feature=youtu.be[/media]

As you see at start - I make silly error of forgetting the loads of rudder I have on left stick to counter the swinging wind !! Makes life very hard for first seconds of flight ... luckily the ailerons were good enough to counter till brain finally realised the error !!

Overall view after flying her couple of times now ... very nice.

Nigel
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Old 08-29-2013, 07:45 AM
  #66  
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For a few days since Saldus.... the J3 has been a pain to get in the air. she would leave ground and immediately bank left and cartwheel. I checked all surfaces, found slight twist in wing possibly from sitting inside car in sun. Heat gun and twist to correct.

Yesterday had another give it the heave-ho instead of RoG. She went of all over the place.... needing lots of trimming. Good job I didn't do RoG! Anyway got her trimmed again...... way different to previous!

Now I hope troubles are over! Just have to create a cowl mould now to make replacement as old is now held together with tape!

Nigel
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Old 09-07-2013, 06:38 AM
  #67  
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Nigel,
I have made a start on mine and I have to say that whilst it is challenging I am enjoying it so far! I am constantly referring to your pics, so thanks for posting them.

The canopy is proving particularly difficult, I received three identical flat pieces of smoked Plastic sheet all shaped as the side windows, is that what you received, or did you receive a moulded one for the front window?

John
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Old 09-07-2013, 06:54 PM
  #68  
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Great job on the build thread, Nigel.
And thanks for posting up your videos, too.

I don't know how I missed this thread when you first started, but I just read it front to back and enjoyed it tremendously.

Love the GB registration too.

John
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Old 09-14-2013, 04:41 AM
  #69  
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Originally Posted by Ghawdex View Post
Nigel,
I have made a start on mine and I have to say that whilst it is challenging I am enjoying it so far! I am constantly referring to your pics, so thanks for posting them.

The canopy is proving particularly difficult, I received three identical flat pieces of smoked Plastic sheet all shaped as the side windows, is that what you received, or did you receive a moulded one for the front window?

John
There should be 2 flat side and one curved front window.

A good material to make windows from : x-ray sheet...... if you have a friend who works in a hospital!

Nigel
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Old 09-14-2013, 04:44 AM
  #70  
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I put the GB reg on nearly all my planes.... basically a reminder of UK and the NCL is my initials.
I also on other models have RC-LV..... based on RC in Latvia where I live.

Nigel
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Old 03-06-2014, 11:24 AM
  #71  
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Default fitting the Rudder

Hello there,

i am building this same kit and thanks to your blog i can figure out some things that are not discribed in the manuel.

But i want to set the rudder, elevator and stabilizer but can not find the exact fit. See picture, can somebody explain me how to? Thanks in advance.
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Old 03-06-2014, 11:25 AM
  #72  
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Old 03-06-2014, 11:33 AM
  #73  
solentlife
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The fin is one piece .... the Rudder is two pieces.

Glue the small top forward piece to the rudder - so you get what you have in your photo ... allowing a small gap of course between it and the fin so it can move.

Elevators are hinged first before rudder fitted.

Nigel
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Old 03-06-2014, 11:36 AM
  #74  
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I have to admit that I am now having a devils own job trying to get her consistently flying !

She has a mind of her own ... she'll take off and then fall to left .... I straighten her out .. take opff again and she falls to right ... there seems no logic to it !

Over time the wing has developed a slight twist with right wing a deg less incidence or so than left ! ...

I shall persevere !

Nigel
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Old 03-06-2014, 11:48 AM
  #75  
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Thanks for your explination. I have set the stabilizer in the push rod holes. Is that a problem or should i raise the stabilizer higher?

And the gap between the tail and the rudder. Is that filled with the Wheel? Thanks
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