Looking for a wing jig

[kc]

Frankly I advise NOT bothering to make a wing jig but just use plasterboard and hold spars down with screws and these little clips.

Clips are made in one length of maybe 6 or 8 and sawn apart after gluing and drilling.  Important thing is the thickness of the spacing part - its just fractionally less than the spar -say 6mm for 6.5mm spar so just sanded down a bit.  This enables it to grip without causing top part to misalign.

 

Edited August 4, 2023 by kc

[Geoff S]

19 minutes ago, kc said:

I built the RCM wing jig and this is what my version looks like

 

 

Construction is fairly obvious from the photo - M6 wing nuts & bolts, 5mm steel rod from B&Q ( selected for straightness by rolling along a surface in the store! ) dead flat ply base, loose intermediate support blocks from same width wood as the support ends.    Each end piece has one Vee notch for rod and one plain to allow one rod to take it's position from the ribs ( for  different sizes of wings also tapered wings )

  However it's never been used!   - I found flat plasterboard to be easier than making perfectly positioned holes in every rib!

 

Perhaps 5 or 6mm carbon rod or tube might be a good substitute for steel - straighter but more expensive

[kc]

Carbon rod perhaps but tube might get crushed by wing bolt pressure.  Expensive!

 

I prefer plasterboard which can be free - offcuts from builders? - or anyway quite cheap at B&Q.   Just take a Stanley knife and a 4ft batten to cut a large sheet to size in the car park ( they won't cut it with their circular saws!) so it fits in your car ( or on your tandem Geoff ! )

[Don Fry]

4 hours ago, Geoff S said:

 

Googling 'models' is always going to have special effects - whether you want them or not is personal taste 🙂

Am aware. Years ago, on a course, had to do a stupid lecture on safety equipment. Rubber boots got an astonishing photo of the members of the association of  New York Gay Firemen. 

[toto]

Hi KC,

 

I like the simplicity of the RCM jig and think it would be easy enough to make. Standard length about 4 feet ? 

 

Cheers

 

Toto

[kc]

Rods are 1 metre length on mine, that would be enough for a 78 inch span wing built in 2 halves or more with wing tips and a centre section.    4ft could be unweildy in the workshop and 5mm rods might sag anyway,so standard 1 metre lengths would do.

However rod type jigs need to have the ribs produced with holes accurately placed or the wing would be useless.  Do your kit ribs or lasercut rib sets have pre cut holes for jig?   If not it will be very difficult to cut the holes afterwards especially for tapered wings where every rib is different.       Re consider before you construct a jig and even try plasterboard first!

 

Only if you cut the ribs yourself ( or they are lasercut with jig holes) would a wing jig be useful- you bore holes in balsa blanks first using a template then put the  blanks on a rib template with stubs to align.  Or if you have plans with jig holes shown then you print every wing rib and stick onto balsa then cut.

 

On the other hand a fuselage jig is so useful and well worth the trouble making one.   If you want to make a fuselage jig I will describe a simple way of making the slotted parts without tools.

Edited August 4, 2023 by kc

[leccyflyer]

As KC said, you would need to be set up right from the word go with very accurately cut holes in exactly the right place in each wing rib - okay if you are laser cutting your own, I guess, but a real pain if you are using ribs as supplied in a kit, or cut by hand, or made using the sandwich method. The flexibility available of using a building board that will take a pin, plus some means of ensuring that the parts are square - either wing rib jigs -which you can buy laser cut or 3D printed - or building blocks and a couple of decent engineer's squares - makes wing building relatively straightforward.

[kc]

I think the fact that I made the wing jig about 15 or 20 years ago and never used it but it just took up space in the workshop tells you how handy I found it!   Very few plans come with the holes marked on ribs.   If wing is tapered or if  there is to be washout then positioning of hole has to be calculated for each rib.  ( or rods jacked up for washout )

 

Plasterboard is so simple and takes pins easily also takes screws extremely well.   Also takes the plan, while with a rod jig there is nowhere for the plan so rib spacing has to be drawn onto spars or TE.  More work and easy to make 2 left halves or 2 right!

[EarlyBird]

2 hours ago, toto said:

I like the simplicity of the RCM jig and think it would be easy enough to make.

Is there a model that you require a wing jig for?

 

[toto]

Not necessarily but it is an option to use one rather than just laying parts on a drawing. 

 

Just considering any potential advantages to retaining accuracy as you progress the build. I'm thinking of the Kestrel here.

 

Cheers

 

Toto

[kc]

Does the Kestrel have the holes already in the wing ribs?  The plan from RCME just shows the 16mm  holes for wing tubes  in some ribs but not all.    Any jig must have rods exactly same size - a sloppy fit will reduce accuracy. 

 

If no holes already then accuracy of wing depends on how accurately you can cut these holes (drilling is hopeless with balsa - brass/copper tube sharpened INSIDE is normally used)

[EarlyBird]

1 hour ago, toto said:

Just considering any potential advantages to retaining accuracy as you progress the build. I'm thinking of the Kestrel here.

The Kestrel ribs are flat bottomed which is ideal for building over the plan. To me a wing jig would add complications with no benefit with regard to accuracy. 

 

Steve

[john davidson 1]

impossible to go back to page one! MODERATOR

[john stones 1 - Moderator]

Flagged.

[leccyflyer]

John - you'll need to press refresh when you get to the advert page. It's the same problem again - someone has been mucking about with the pop up ads.

[Graham Bowers]

10 hours ago, john davidson 1 said:

impossible to go back to page one! MODERATOR

Try the "Brave" browser.  That's all I use now, and it gets rid of all of the pop-up ads.

 

Also gets rid of the adverts on Youtube that are before and within many videos.

 

I learned about it on this forum, by the way.

[Piers Bowlan]

I think modellers have been making wings straight and true for decades using just a perfectly flat building board with balsa parts pinned to it. Either plasterboard (my local B & Q sells ready cut pieces) or  self adhesive cork squares available from eBay, work well.

An alternative to pins is to use a magnetic building board. Some people swear by them and I have seen them for sale at some of the model shows in the past. Thinks 🤔:- must try one sometime.

If the wing has washout just place a strip of balsa along the TE at an angle, such that the root rib is flat on the board while the tip rib is raised by the strip. If you are worried about glueing the ribs to the strip, cover it with some shiny sticky tape. 

[Piers Bowlan]

To add a further note on building wings, I mark the rib positions on the LE And TE stock. I then make a small indentation maybe 2mm deep so the TE & LE of the ribs fit snugly into the stock to increase glueing area. It is surprising how much stronger the joint is than just butt jointing and you end up with perfectly spaced ribs 😊. (A couple of old blunt hacksaw bladed taped together make a nifty tool for cutting small slots) If I am cutting my own ribs, I normally make them a little longer to start with but if they are from a laser cut set I don’t lose sleep if the chord is reduced by a few mm!

Just my 2p worth!

[leccyflyer]

I like to notch the TE and LE as well, I agree that it makes for a stronger wing - you make a good point about the laser cut ribs will end up a couple of mm short when doing that.

[Piers Bowlan]

Personally I cannot see what a wing jig will provide that a flat building board won’t. On the other hand the Great Planes type jig requires the holes in the ribs to be cut with laser accuracy as kc pointed out. The steel or carbon fibre rods are the ‘datum’. A datum is provided by a flat building  board. There might be case for a wing jig with a semi or a fully symmetrical  wing section but I have built those before on a flat building board too, either using rib-tabs or by shimming the LE & TE with care. So not really a problem.

So rather than spending money on a wing jig I would buy more balsa, but that is just me! 😁😁😁

[leccyflyer]

Agreed - the considerable hassle level involved in getting such a wing jig to work, compared to the ease of use of a nice flat building board, is such that you could likely guarantee that after one use it would probably be consigned to being an awkward thing to store for the next decade.