Making serrated rib tapes

Greyhead · 05-12-2004

Making serrated rib tapes for fabric-covered wings can be a problem but this simple tool can at least speed up the process even if it still remains a mind-numbing job. In essence it consists of a hacksaw blade fitted to a length of pine, the rib tape material is trapped against the blade and torn into strips.

Hacksaw blades come in many shapes and sizes so choose one that will produce serrations of an appropriate size for the model you are building. My Elf was 1/6 th scale and 18 teeth to the inch seemed about right.

I’ll briefly describe the design but a quick look at the photo below will I’m sure make things much clearer. 2 screws attach the blade to a length of pine, hinged to another length that is used to trap the rib material against the blade. Drill 2 holes for the screw heads to allow the blade to fit tightly when the 2 pieces are brought together and draw a line parallel to the blade to help align the paper for tearing.

The best material for the tapes that I’ve found to date is high quality tracing paper, but by all means experiment and if you find anything better then please let me know! Fasten the paper down to stop it curling, give one side a coat of Balsaloc and leave it to dry overnight. Mark the edges of the paper at the width of tapes required.

The more solid you can support the tool the better; I use a large vice attached to a substantial workbench. Put the paper in the tool with the glued side towards you, align the edge marks with the line on the tool and grip it in the vice. The paper has a definite “grain” so try tearing in different directions to find the easiest, actually tearing the paper takes a bit of practice so expect to have a few failures until you get the knack. After the first tear move the paper down so the next edge marks are in place and tear again.

The rib stitching is embossed from the glued side, make a paper guide to ensure even spacing and press gently with a precision screwdriver.

The tapes are now fixed over the rib positions etc. with a film covering iron, don’t use too much pressure on the embossed “stitching” and you’ll end up with a very realistic rib tape.

Hopefully the attached photos will encourage you to “have a go” on your next scale model, you’ll be amazed at the increase in the level of realism and strange as it seems they are very visible in flight!

Just had a look at the attachments and the one of the finished tapes isn't very good, for better views click on the link Another Parnall Elf

**wonwinglo** · 05-12-2004

[quote=Greyhead]Making serrated rib tapes for fabric-covered wings can be a problem but this simple tool can at least speed up the process even if it still remains a mind-numbing job. In essence it consists of a hacksaw blade fitted to a length of pine, the rib tape material is trapped against the blade and torn into strips.

*** That is a great tip which I will certainly be trying on my next model,as you point out they are very distinctive when the model is in flight.
It is interesting to note that rib tape serrations vary on world war 1 type aeroplanes to those produced from 1930 onwards,the early fabric workers would cut the fabric to width and then draw the weave of the fabric with their hands outwards,this was called 'Fraying' then the authorities developed 'Pinking' or pinked edges to the fabric,this was arrived at by cutting the fabric with specially cut shears which gave a serrated edge,the idea by the way is not just cosmetic as it is done this way should the fabric lift under the slipstream effect,it was found out by tests in wind tunnels that serrations added to the fabric was the best safeguard against this happening.
The well known case of the prototype Westland Lysander shedding its fabric in flight was caused by a combination of the fabric billowing and a lack of any stringing to the fabric,the pilot put the aircraft down safely desopite this traumatic experience ! the rib tapes are sewn through the wings with a long needle and beeswax coated thread,a long and tedious job,the knots are then locked at each rib position to hold the fabric taught.

Greyhead · 06-12-2004

Barry

In the end, once you’ve got the technique sorted out, serrated rib tapes are probably the easiest.

The rib tapes for WW1 were invariably of the “frayed” type and these are simplicity itself to model. Cut, or better still, tear strips of Solatex to the required width; tease out a couple of threads from both edges and the jobs done. This, however, leaves the “stitching” which cannot be simply embossed, it will disappear as the Solatex shrinks whilst being ironed into place.

I feel another “tutorial” coming on!

Grahame

**wonwinglo** · 06-12-2004

Quote:

Originally Posted by Greyhead

Barry

In the end, once you’ve got the technique sorted out, serrated rib tapes are probably the easiest.

The rib tapes for WW1 were invariably of the “frayed” type and these are simplicity itself to model. Cut, or better still, tear strips of Solatex to the required width; tease out a couple of threads from both edges and the jobs done. This, however, leaves the “stitching” which cannot be simply embossed, it will disappear as the Solatex shrinks whilst being ironed into place.

I feel another “tutorial” coming on!

Grahame

*** Hello Grahame,I have just done a quick test strip and sure enough it works well,to simulate the stitching fill a syringe with thinned PVA adhesive,apply in fine lines and then add the cross stitching with a small dash of adhesive,this shows nicely under a coat of colour,practise before you add this to your model,you soon pick the idea up.

Phoenix · 06-12-2004

just a idea but you could superglue some thin string to the bits that need the stitching embossed bits

**wonwinglo** · 06-12-2004

Quote:

Originally Posted by Phoenix

just a idea but you could superglue some thin string to the bits that need the stitching embossed bits

*** Thanks Iain,always the simple basic ideas that work best.

Greyhead · 06-12-2004

I was thinking of doing another tutorial for Non-Serrated Rib Tapes but as this one has developed I’ll just add this here!

The way to do it is to fit a row of panel pins spaced at the distance between “stitches” along opposite sides a piece of wood. Put a sheet of paper between the pins; thread thin cotton from pin 1 one side to pin 1 opposite side, down to pin 2 and back to pin 2 on the original side on so on. Give the lot a coat of dope to fix the cotton to the paper, when dry turn the paper over and give it a coat of Balsaloc. Cut the paper into strips the width of the “stitches” and fix to the rib positions, then add your frayed rib tape over the top of the "stitches".

**wonwinglo** · 07-12-2004

Quote:

Originally Posted by Greyhead

I was thinking of doing another tutorial for Non-Serrated Rib Tapes but as this one has developed I’ll just add this here!

The way to do it is to fit a row of panel pins spaced at the distance between “stitches” along opposite sides a piece of wood. Put a sheet of paper between the pins; thread thin cotton from pin 1 one side to pin 1 opposite side, down to pin 2 and back to pin 2 on the original side on so on. Give the lot a coat of dope to fix the cotton to the paper, when dry turn the paper over and give it a coat of Balsaloc. Cut the paper into strips the width of the “stitches” and fix to the rib positions, then add your frayed rib tape over the top of the "stitches".

*** This will certainly give the right effect,the unsightly rib stitching shows through the serrated tape which is pulled tight as a drum by the doped fabric,next time you see a doped wing you will see what I mean,sometimes scale modellers portray these things as too neat and tidy.
To understand the sequence for those not familiar with it here it is-
1/ Waxed cord is threaded through the wing fabric alongside a rib,the long needle is taken down and upwards the other side and the first knot is locked into place.
2/ The cord is taken running alongside at right angles to one of the ribs and then the needle is again pushed through the side of the rib again taken around the rib and a knot locks this in place.
3/ And the process is carried on until the full length of the rib is completed finishing with a final knot,it is a long skilled job to complete neatly and takes a lot of patience just as on our models.
4/ Finally rib tapes are placed over th stringing starting at the trailing edge,wrapped around the leading edge and finishing at the lower te.

Greyhead · 08-12-2004

Of course the perfect way would be to actually stitch the covering to the ribs using thin cotton! Bound to add a bit of unnecessary weight though, but I might be tempted to give it go on my next model.

**wonwinglo** · 08-12-2004

Quote:

Originally Posted by Greyhead

Of course the perfect way would be to actually stitch the covering to the ribs using thin cotton! Bound to add a bit of unnecessary weight though, but I might be tempted to give it go on my next model.

*** It would be worth a try Greyhead and add a lot of torsional strength as well to a lightweight wing,but more of a labour of love to execute.