Hobby King J3 Cub Laser Kit build

[solentlife]

This kit has caught my eye a few times and I umm and argh about whether to click buy or not .......... finally I succumbed ... something about the little J3 Cub ...

Kit link :

http://www.hobbyking.com/hobbyking/s...dProduct=22527

The assembly instructions are there with good photos but various areas are poorly explained - mainly because of lack of good translation I think from Chinese to English ....

Anyway lets get on with it.

It all arrived with various other items ordered for it ...

2826-10 1400kv motor :

http://www.hobbyking.com/hobbyking/s...dProduct=12920

7x6 prop
Yellow covering film
30A Red Brick ESC

Probably overpowered, but then I think a Cub should be flying on a low throttle and not screaming like a banshee !

The panels of Lite-Ply and Balsa were all laser cut and all pieces had small tabs left uncut to h9old them in the sheets. Quick nick with knife and poarts are free AS YOU WORK. Note as you work ... no parts are marked except by the instruction sheet provided. So I find it best to only remove what is necessary for that session ... dry fit to check then glue up.

Note that I am also tracing the parts onto cheap 'Floor insulation foam' for a lightweight foam version later .... also it keeps templates in case of repairs of original.



I prefer PVA wood glue for these jobs ... has a bit of give to it, dries reasonably light but is a slow set solution ... If something needs tacking while drying - a blob of Superglue applied will tack an item.

Start organising first parts for fuselage ..



Here's where first confusion starts ... it says 9 bulkheads but there are 10. Then you realise that the big ones E5 + E7 should be glued together to form one front cabin / wing dowel bulkhead. The slot in fuselage side is 2x width of all others !!





All bulkheads now in place and PVA setting up before adding other side ...



More later ....

(For those eagle-eyed ... yes I am building on a thick sheet of foam sitting on a chair !! My office desk is covered in model bits ... my model den is a store for all sorts ... running out of space !! Actually the foam is good as I can pin through .. it's stable ... I can move it ... etc. The model is not that big anyway ... )


Nigel

[Dereck]

One day, the Chinese economy will crash and all the Chinese consumers with any money left will be buying cheap stuff made in the US.

Then we'll get them back by translating instructions from English to 'Englinese' by online translator

That's a joke.

I hope...

Not a bad looking kit. How's the cowling dealt with? Be a good one to do as a Super Cub, unless you have a passionate desire to make little dummy jugheads for a J3.

Looking forward to seeing how she ends up

D

[road king 97]

Good find on the cub kit but you guys get better shipping price than us over the big pond do i think. Still for a laser cut kit its a great price. joe

[solentlife]

This is no kit for someone without 'ingenuity'..... too many things not explained or shown properly.

For some items I actually took a magnifying glass to study the photos !!

OK ... fuselage is jigged on workmate and left overnight :



Now this may sound strange - but longerons that are along top and bottom of fuselage sides I slide in after ! Why ? I use PVA glue and trying to work two fuselage sides and formers and longerons at same time ? PVA allows me to flex the structure next day to insert longerons and straighten up structure ...

OK they've been added BUT how far do they run ? Study of photos and motor bulkhead indicate they run right to front of fuselage sides. But at rear ? No info - so I decided to curt a little short to allow rear sides to come together matching the fuselage bottom.



Adding longitudinal's ... these have a hard angle change near cabin and may be better to dampen first at that point - mine cracked but use of CA and PVA have restored these ..



Next is fuselage bottom .... now this is sized BETWEEN full width and inside fuse sides width !! But I have used the PVA to fill and set in place using it's form to ensure fuselage is straight.



We now come to the nose section and this really is a DIY sort it yourself area ... you have 2 firewalls, 2 battery 'tables' .... Nothing in instructions about there being two of each. So I assume the 2 firewalls are a sandwich affair to give depth for motor mount etc.



First I PVA'd in place and taped correct ... then second I epoxied in behind for strength ...



I have added 2 foam strips inside the nose to align the battery 'table' after having checked with a my 3S 2200 for room needed ...



The foam is only temp and will be replaced with full depth foam to completely line that area to add to the thin balsa ... without incurring weight.

She's now sitting there glue setting up and ready for tomorrows cont....

Note about scale additions .... given the foam we have nowadays - I can add the engine and exhaust bits etc. without weight penalty using scrap foam. The UC and struts will be via Bicycle wheel spokes bent to shape ...
I already have suitable wheels on hand ...

Nigel