Jocasta

[Jim Newberry - Nuviation Ltd.]

Colin, don't panic. It sounds as though you are only adding a few small slivers of balsa to the rear fuselage. While you are quite right in being concerned at adding any weight to the rear of the model, the overall weight gain will be minimal.

Jim.

[Colin Anderson]

Cheers Jim. I just wished I'd not made the error in the first place! I guess there's a first time for everything. 😊

[Jim Newberry - Nuviation Ltd.]

It's all part of the process - one of the great things about this hobby is the endless capacity for learning new stuff - you can never know everything, in fact the more you think you know, the more you realise there is to learn. That's why it's so darned addictive!

[Robert Berger]

Hi Jim,
Where to from here? The main spars stop at R1B on both wing panels but the dihedral braces go right through although they are on the back side of the spar which is not correct. I will add the second R1B to each side of the center section and a R1 in the middle of the center section. I planed to epoxy the mid section spars onto the ends of the wing spars and likewise the 1/8 x 1/8 balsa spars and the leading edge. But is that enough? I feel that maybe the wing spars should have come through into the center section but of course they would be on a downward angle. I intended to laminate the cener section R1B ribs with epoxy to the wing root R1B's also.

[Jim Newberry - Nuviation Ltd.]

Hi Robert,

The dihedral braces do indeed go behind the spars but should not be fitted until much later on. Have you glued them in place? The way you would normally build the wing is to make up all three panels, including sheeting top and bottom and adding the leading edge. The inner faces of each panel are then sanded smooth and a thin strip of sheeting cut away top and bottom to accept the braces. The centre section is then weighted down flat on the building board with the outer panels propped up to give the correct dihedral and the rib faces are glued together with slow setting glue while the upper dihedral brace is slotted into its recess and glued in place. Once everything is dry, turn the whole assembly over and add the lower brace. Once everything is dry again, replace the strips of sheeting you removed to fit the braces and add fibreglass bandages over the joints where the rib faces meet.

Jim.

[Colin Anderson]

Looking at the images above, those dihedral braces look as if they are made with lite ply. Or maybe I'm seeing things. 😊

Looking at the longerons; as these are 3/8" x 1/4", wouldn't they be structurally stronger the other way up? Just asking. 😊

[Jim Newberry - Nuviation Ltd.]

I wouldn't recommend that Colin, you will end up removing a lot of material from the ribs (I'm assuming you're referring to the spars rather than longerons). The orientation shown is the usual method used.

[Colin Anderson]

Sorry Jim,

Yes, I meant the spars; and yes, I agree with you, it would mean removing too much material from the ribs. It was just a thought. 😊

[Robert Berger]

Hi Jim
Yes dihedrals are glued in place. I incorporated them into the starboard wing panel and then set that wing panel up on blocks to get the port side dihedrals to match up with the port spars. That is how the Project X build went in the RCM&E magazine recently. I have two options here

1) I can do everything that you say above but it means building the centre section in situ.

2) I can cut through the dihedrals and separate the wing panels and build it as you say but the new dihedrals will be glued to the backside of the existing dihedrals and that wont be a problem as long as I glue the same ply to the rear of the center section spars before I put in the brand new dihedrals.

Now, fiberglass bandages.... Ok I have fibreglass mat that is 50mm wide so I assume that is what you are talking about. Are you suggesting that this is laid over the joint (for to aft) on top of the balsa skin and resined in place? If so that is going to be 1mm thick and quiet visible under the covering. Or is there a different way of doing that from what I am imagining? Do you have any pictures of that method?

[Jim Newberry - Nuviation Ltd.]

Hi Robert,

I reckon your best bet is option 2. That will be the easiest from a building point of view as building the centre section in situ will make it very difficult to shape the leading edge.

As for the fibreglass, yes I suspect we are talking about the same thing. I use the term bandage as opposed to mat because, to me, mat is the chopped strand stuff with the fibres lying in random directions whereas the bandage - of the sort sold in model shops as a "wing joining pack" or similar - is a woven strip. I can put some pictures up but I'll need to ask you to bear with me as I am going to Tokyo in the morning with work and will be away until the weekend, after which I will need to set up a test piece, photograph it and upload the pictures. In the meantime, here is a description of the process:

Take your newly joined wing panels and lay the fibreglass bandage along the joints. Lightly draw pencil lines along each side of the bandage, allowing a few mm either side of the bandage - in other words, if you are using 50mm bandage (which is what I used), then you should end up with two parallel lines approximately 60mm apart running fore and aft equally spaced either side of your panel joints. Now, using these pencil lines as a guide, paint mixed epoxy resin onto the panels. Use slow setting resin, not the 5 minute stuff. If you are confident, you might be able to use 30 minute resin but I use 24 hour resin to allow plenty of time. Now lay your bandage over the painted resin - start at the trailing edge with at least an inch to spare, work your way forward, over and around the leading edge and back to the trailing edge. Use more resin to stipple the bandage and thoroughly wet it. The best tool I have found for this job is a cheap 1" decorator's brush with the bristles cut down halfway along their length to make a square brush with a flat end, as if you were going to stand it on the workbench on its bristles. Use the brush to stipple the resin into the weave of the bandage - don't try and paint it on as you'll drag the bandage. As you work, some bits of bandage will lift from the surface of the wing but just gently nudge them back into place. Obviously, when you turn the wing over to do the other side, the bandage you have already attached will fall away so just rotate the wing until it is pointing upwards (as if the model was climbing vertically) and do the underside. When you get back to the trailing edge, there is no need to try and wrap the bandage around it as you did with the leading edge, just leave an inch or so of bandage loose, which will now be sitting more or less parallel with the first end you started with. Clip these two pieces together with a clothes peg and, keeping the wing in its current orientation, go back over both surfaces ensuring the bandage is wetted out over its full length. Obviously, you will have to repeat this process on both sides of the centre section, however I would recommend stopping and allowing the first side to dry before attempting the second. So, carefully set the wing aside in its vertical orientation and leave it to thoroughly dry for a day or two. Having repeated the process for the second side, remove the excess length of bandage from the trailing edge by cutting it with a Stanley knife or similar before sanding it flush to the trailing edge with a sanding block. At this point, as you mentioned, you will have two unsightly strips of wing joining bandage which would look a royal mess through the covering. So, using fine sandpaper and wearing a mask, sand away the rough surface of the bandage until it is nice and smooth - this is an easier process than it sounds as the epoxy resin sands easily. I prefer to use my fingers to support the sandpaper, rather than a sanding block, as it gives me more feel as to the lumps and bumps in the resin. Do what you can to feather the edge of the bandage so that it is less apparent under the covering but try not to scuff the adjoining balsa wing skin too much. Once the wing has been covered, the fibreglass bandage will be visible under the covering but it should not be noticeable from more than a few feet away, and will be all but invisible in flight.

Sorry that has been quite a lengthy description but hopefully it helps - I will do what I can to get some pictures up here when I get back from work.

Jim.

[Robert Berger]

Hi Jim,
Thanks for the lengthy but fantastic description. It is totally clear and I fully understand it all. I will do all od that including option two and put up pictures as I go. Have a great trip to Tokyo.
Robert. (In New Zealand)

[Robert Berger]

I did that Jim and I then had three wing sections.

Using me straight-edge I lined up the leading edge and lifted the wingtips 47mm at the wingtip rib. This matched the dihedral brace angle perfectly.

Interestingly the port wing was made when we had a hot day and the starboard one was made the next week when the weather was more humid. The starboard wing panel is 4mm longer that the port. I suspect that the paper plan had shrunk with the dryer weather. If I had of noticed that before I joined the three sections, I would have added a 4mm thick wing root rib to extend that panel and corrected the difference.

[Hannes Koekemoer]

Hi all, and merry Christmas!

The time has almost arrived when we will be near a hobby shop (hooray!) and I was wondering what parts I should buy first as my budget is too small at the moment to buy everything in one go.

What do you suggest?

[Andjo]

Hallo Hannes,

Your name suggests Dutch origin? Ik woon in Belgie in West Vlaanderen.

I also have a small budget and I have started with the 2 wood packs. Luckily a friend brought them to me from the UK. As I am not a quick builder and spend maybe 2 - 3 hours a week it gives me plenty of time time to save for the drive train etc.

I think Jocasta is superb despite the few problems with the CNC parts from the early packs, I have learnt a lot from all the friendly folks on this forum especially Jim.

I wish a Happy and Healthy New Year to all. 😀

Andre

[Hannes Koekemoer]

Thanks Andre

I am actually from South Africa, but my name does originate from that area, and I could understand you too as my home language is Afrikaans which is very close to the same language.

I think I will start with the wood too, but will probably cut them out myself (I like working with wood), then probably the heat shrink plastic. The next one for me would probably be the motor, esc and receiver (I already have servos and a 3S lipo, but only 2200mAh so I will buy a bigger one later)

(P.S. In Afrikaans it would be: Ek woon in Wes Vlaanderen in Belgie. (Almost the same)

Hannes

 

Edited By Hannes Koekemoer on 28/12/2014 10:17:55

[Hannes Koekemoer]

I think I have just found another error on the plan.

While I was measuring from the plan to buy the balsa wood, I noticed that the wingspan was actually 69" on my plan and the fuselage was 46", will this make any difference to the flight performance or integrity?

I find this a little strange.

Hannes

[Colin Anderson]

You're not wrong Hannes! I measured my wing today, after reading your post; once I put the wingtips on the span will be 70"! Strange, cause I thought this was a 60" span model, which would be an ideal fit in my car; my Cub is 72" and I have to wind down the back window and leave a wingtip sticking out! Not ideal.

[monty2]

I'm well on with the wing, but have some issues -personally which slow me up. In 2000, I suffered a stroke fro which I have recovered but 12 months ago I had an aortic Aneurism but thanks to a great health care system in the UK, I'm still here. So too all you fellow Modellers, Have a great and fantastic New Year for 2015.

That is the most important part, I'm here and so are you, so go for it and enjoy life, its the only one you have.

Happy and prosperous and enjoyable 2015.

[monty2]

As my previous post, the wing is well done but I have reached the Ailerons, there construction is not, to me so obvious. you show a piece od ply, is this instead of the 1/16th on the ribs or between them.

Also using both views I am not 100% sure of the construction, about 85% yes but not 100%, can you clarify for an old duffer please?

[Jim Newberry - Nuviation Ltd.]

It might help to think of it like this - the aileron construction follows a similar form to the rest of the wing in that you have a trailing edge, capping strips top and bottom with ribs in between and a leading edge. The difference is that the leading edge is shaped into a shallow V where it meets the rear face of the aileron recess in the wing itself. The hinges will fit in slots cut into the apex of this V. You will notice that the apex of the V is slightly closer to the upper surface of the aileron than the lower - this facilitates the necessary differential movement of the aileron whereby more movement in an upward direction is required than downward. The ply that you mention is a plate which sits under two of the ribs and replaces the capping strips under those two ribs. It is 1/16" thick - the same as the capping strips on the other ribs - and its purpose is to provide a secure anchor point for the aileron control horn. When it comes to cutting the wood for the leading edge of the aileron, cut it wider than it needs to be so that once it is placed on its edge on the building board there is plenty of spare wood to trim back to sit flush with the upper edge of the ribs and capping strips, bearing in mind that the triangular section of the ailerons means that, prior to shaping the V section of the leading edge, the forward face of this piece will be higher than the rear face, if you see what I mean (that was all a bit involved so if it's not clear let me know and I will either send you a drawing or try to explain it better).

Here is a suggested build sequence-

1. Pin down the trailing edge.

2. Position the lower capping strips on all rib positions EXCEPT for the two ribs that align with the servo bay in the wing.

3. In the space you left at step 2 above, fix a ply plate which spans approx. 1/8" (3mm) beyond the edges of the ribs. (The reason for this overhang is purely cosmetic - it ensures that the gaps between one capping strip and the next, and then that capping strip and the edge of the plate, are equal - if your ply plate stops at the edge of the rib it will be just as strong).

4. If required, trim the front edge of your capping strips and ply plate to align with the front edge of your aileron ribs. You can do this by using a straight edge aligned with the forward edge of the ribs as shown on the plan along all the strips or by using one of your ribs as a guide to ensure it precisely fits the ribs you have cut (dare I suggest that, given some of the foregoing discussions about inaccuracies in the plan, it might be best to use this method.)

5. Glue your ribs in place.

6. Cut a strip of balsa for your aileron leading edge, ensuring that it is more than wide enough to extend from the building board, up the forward edge of the ribs, past the (as yet unfitted) upper capping strips plus an allowance for the wing section.

7. Now fit the upper capping strips.

8. Trim the upper edge of the leading edge to sit flush with the upper capping strips.

9. Remove the aileron from the building board and trim the leading edge to the V shape shown on the plan. The apex of the V should not be a sharp point as this will make it too fragile. A flattish point of around 1-2mm will be fine.

10. Make sure that the aileron fits in the recess provided in the wing and sand all over.

The hinges and aileron horn will be added after covering.

Job done - hope that helps!

Jim.

 

Edited By Jim Newberry on 03/01/2015 17:04:32

[monty2]

Thanks, that more than helps, it clarifies the whole construction of that area, I was part way through building the aileron when I got your answer, so now I can do it properly..

[Den Moran]

Hi Jim! Happy New Year!

Sorry to be a pain, but can you give me the name of the decal people again, please? Ready to join the wing pieces now, so looking to order them over the next week or so.

Thanks, again,

Den, Abertawe

[monty2]

I was about to join wing bits when lo and behold the love of my life, 18 month old Emma arrived. Oh dear, she wanted to join granddad and find out what he was doing. Those with Grandchildren will know hat happened next. Horror's I need to cut all the ribs etc., to make another wing.

Great game or so she thought. I still love her,. honestly. must be a big softy.

[monty2]

sorry to be a pain, but another issue, you have 6 WT bits on the on the tip plan but the upper bits don't all show in total on the plan, nor do the lowers match.

Neither are they all cut on the kit

Looks like whoever set up the laser cut bits didn't check anything now. Brain not in gear.

This is back to the old test, check and check again before doing anything. Then try building before you sell to the public. The only way to preserve your reputation

[Jim Newberry - Nuviation Ltd.]

Hi Monty,

On this occasion I don't think there is a problem with the plan. WT1, WT2, WT3 all have upper and lower segments. WT4 and WT6 both feature on the upper side only while WT5 features only on the lower side - as the plan explains. Admittedly, it would have been clearer if WT5 on the wing had been drawn as a dotted line, however the orientation of the WT parts on the right hand side of page 2 of the plan, along with the word "lower" on those pieces that fit on the lower side should hopefully make things clear. Hope it doesn't take you too long to correct your granddaughter's handiwork!

Den - I used Pyramid Models **LINK** - If you send them an email they should be able to help.

Jim.