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2022 Mass build MK Joker 25.


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The nice weather this week means I have not been building.

However I need to crack on with the Joker as I now have some models to repair (or replace).  :classic_wacko:

 

Having fitted the undercarriage mountings I then fitted the leading edges.

This was followed by the wing joiner, half to each wing.

The two wing halves could then be joined flat, upside down.

I could have done the leading edge sheeting first, but it made little difference as I have a reasonably large working area.

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Kevin, could you explain further about the WC3 and it's opposite concave item - are they balsa and if so how is the concave part formed?   I was expecting lasercut ply items perhaps several layers of 1/8 top and bottom! 

Also the u/c bearers - they look as if they are several layers laminated from ply.

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Posted (edited)

WC3 is was cut on my bandsaw from a piece of 19 x 39 x 72mm balsa.

The undercarriage mountings were cut from 6mm ply and shaped on my mini circular saw.

They could be made from 2 laminations of 3mm ply as you suggested though.

Next is the top sheeting.

 

 

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Edited by kevin b
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Thanks Kevin.  I can now see from that photo that the u/c bearers fit over W15 and W14 while a bit is recessed to fit between W15 and W14.  Easy to make in 2 layers ply with diffferent widths.

I see how you shaped the balsa now - my bandsaw and my skill with it won't allow such accuracy!

 

It seems that W19 and W20 are not used unless retracts are fitted.   One either fits W15 and W14 or W19 and W20, but not both.

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I have to say that looking at the wing that it's obviously a bit stronger where the u/c blocks are and also in the centre section but less so between W3 and W4 which is always where wings tend to break -just outside of the fuselage!    I wonder whether you might consider some reinforcement before you sheet the wing?   Maybe a piece of sq spruce from one u/c bearer to the other,  with a shorter piece on the top side?

Edited by kc
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I will stick to the plan as far as possible when I build one. Too many extra belts and braces quickly turns into a heavy model which doesn't match the handling of the original. 

 

That's the beauty of building from a plan and kit, we can each personalise to our own taste 

 

Keep 'em coming Kevin 

 

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Now then. Wing sheeting.

I started with the top as it is flat.

That way I could fit the centre sheets across the wing join for added strength.

The full leading edge sheets are curved and taper, so have to be fitted individually.

Then the cap strips are added and we are ready to turn over and start again.

Only on the lower side you have to fit all the sheets separately due to the dihedral.

Once the wing is covered it can be made to fit the fuselage. 

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Now the wing can be made to fit the fuselage.

First of all the WC 4 trailing edge parts need to be fitted.

I replaced these with a single, thicker piece of wood which was then shaped to fit.

This will increase the strength of the wing join and I will also be fitting a larger piece of ply where the wing bolt goes through.

As there is no tuned pipe the centre section will be covered as well.

 

Once the glue has dried and shaping done the wing leading edge can be shaped and fitted to F24 using dowels to locate it. Making sure that the wing is fully seated on the fuselage.

Note. The dowels do not at this stage go into the wing itself until F24 is glued in solid. then the wing can be removed and the dowel holes drilled.

Note 2. I forgot to mention when sheeting the fuselage that I had not fitted the tail skid. This was because I am going to fit a steerable tail wheel (we have a rough field !).

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I have am just finishing producing the wood kits that were requested and have sufficient materials to produce one more if anybody is interested.

The kit contains all the wood required, a full plan and a Petg canopy. The cost is £110.00 including U.K. delivery. You would have to provide your own hardware, adhesives and covering materials.

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Rapid progress Kevin!

A couple of questions come to mind that might help other builders---

Did you fit WC2 ( inner cross piece for dowels) before sheeting the wing or is this unnecessary?

 

What angles did you bend the torque rods - is there  built in differential considering the plastic pivots have the pivot point a bit forward of the wire?  

Edited by kc
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I did fit the WC2 parts, yes. After F24 had glued the wing was removed and then the dowel holes drilled, I used a slightly smaller drill to make sure that the dowels were a firm fit in WC 2.

The torque rods are just standard Radio Active ones, but if you are fitting a central wing bolt I would suggest moving them further apart.

I will be showing that shortly. 

 

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Kevin,  one point has arisen in fuselage assembly which is not shown in your photos -  F5 seems to need to be inset into the fuselage sides by 5mm ( I mean actual fus sides not just F11 ) whilst F4, F6,F7 etc are just inset into F11 and the shoulders rest on top of fus sides.   Can you confirm this is correct?   The line of F19 seems to depend on this being correct.

Edited by kc
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kc.

Here is another photo, if it helps,

F5 glues inside the fuselage ply reinforcement. There is no slot in F11 to accept F4. It just glues between the ends of F11.

Remember it is not set vertical.

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Thanks for that Kevin.   I think the slots I cut in F11 were not quite deep enough.   

Actually I think F4 is vertical on the plan although it could be read a different way - it looks like it's the line of the canopy that slopes.   However if the lasercut parts are intended to slope then thats obviously the way it needs to be assembled, otherwise the height won't match F5 and F6.  

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Actually, you are correct. F4 is vertical.

I think I moved mine back, which meant I had to slope it to fit.

This morning I found I had glued WC4 on upside down and the aileron controls were on the outside.

I think I will have to stop working late on an evening !

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6 minutes ago, kevin b said:

 

This morning I found I had glued WC4 on upside down and the aileron controls were on the outside.

I think I will have to stop working late on an evening !

 

Plus one for No Late Night Working Kevin

In a past life I thought I was clever finishing school reports very late in the evening.

They were of course complete nonsense when I read through in the cold light of day.

How often has any of us built two port wings late at night, my hand is up !

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Now the wing dowels are fitted we can install the wing mounting bolt to secure the wing and check its alignment.

At the same time the battery cover is fitted in place.

I also enlarged WC5 to fill between the F23 parts. Just to increase strength.

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  • 2 weeks later...

Having got the wing to fit the underside can be finished off

The wing bandage was fitted before the final sheeting.

At the tail end more work was  done while waiting for the resin to dry.

Then the wing was installed so that the tail could be aligned.

Soon be time for  - sanding (groan).

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Posted (edited)
1 hour ago, john stones 1 - Moderator said:

Very nice Kev, Stewarts a lucky fella. 👍

Not quite sure about that, but he does have a smile on his face.      😉

(he only agreed to do it on payment of a banana)

Edited by kevin b
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  • 2 weeks later...

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