World War I Biplane Rigging

Easy installation for flying and landing wires By Gerry Yarrish [email protected] Photos by the author As seen in the October 2023 issue of Model Aviation. Throughout the years, I have built several Giant Scale biplanes. One requirement for most biplanes is the rigging wires that add strength to the wing structures. I very much enjoy scale modeling, but for rigging wires, I prefer to simplify the installation. You can use turnbuckles to tighten the cables, but I like to use standard RC hardware. If you are just starting out, this will be a good way to gain experience. To get started, you’ll have to decide what attachment setup you want to use. For my Nieuport, I have permanent attachment tabs on the tops of the cabane struts and permanent lower-aft anchor points. I then added attachment brackets to the top and bottom of the interplane V-struts. These are made with alignment pins to guide the positioning of the struts, as well as holes that match up to the blind nuts installed in the wing panels. Before adding the rigging wires, install the V-struts, as well as the lower attachment brackets to the bottom corners of the firewall. I prefer to work from the fuselage outward, but it doesn’t really matter.

Pro tip: Make sure that none of the rigging wires come in contact with one another. If they do, either adjust the attachment points or add a length of heat-shrink tubing to where the two cables rub together. Shrink the tubing and add a drop or two of thin CA.

Attachment Brackets

There are two ready-made sources for attachment brackets: steel landing gear straps from Du-Bro and heavy-duty battery solder tabs that are used to make RC car battery packs. I prefer the 0.020 × 1/4-inch solder tabs because they are more than strong enough and come plated with a rust-preventing coating. They’re available online and from electronics stores (Photos 03 and 03A).

Getting Started

I think the best way to get started is to use the 1/4-scale Deluxe Nicopress Starter Set from Balsa USA. The kit comes with enough 1/32-inch braided cable for an average 1/4-scale biplane, a Nicropress crimping tool, and several swage crimps. It also comes with a size gauge to check your finished cable swages. Here’s what’s involved for each cable end using Balsa USA crimps. Photo 01A shows the cable end hardware with Du-Bro crimps and the Sullivan clevis tool. Photo 02 is the Nicropress crimping tool from Balsa USA. In Photo 04, the flying wire attachment brackets are installed on the lower right corner of the firewall. In Photo 05, the landing wire attachment bracket is attached to the bottom of the right V-strut. One of the attachment brackets is located at the top of the right V-strut for the flying wires (Photo 06). As shown in Photo 07, start by screwing the threaded cable end into a clevis along with a 4-40 locknut then slip a crimp onto the cable and insert the cable into the hole in the end of the threaded cable end. Photo 07A depicts the beginning of the Du-Bro crimp installation. Fold the cable back around and place the end in the crimp (as shown in Photo 08). Snug the crimp back to make the cable loop smaller, as shown. The Balsa USA crimp has been swaged. In Photo 08A, the Du-Bro crimp is in place with the cable looped back. As shown in Photo 09, center the crimp in the 1/32-inch cable jaw and close the tool jaws to squeeze the crimp. Move the crimp to one side and squeeze the crimp again for a complete press. Photo 09A shows the first press for the Du-Bro crimp. Attach the clevis to the attachment bracket, as shown in Photo 10. Notice the completed crimp. Next, attach the second clevis to its attachment bracket, as shown in Photo 11. In this case, it is the drag rigging wire attached to the front bottom of the V-strut bracket. I measured the length of the cable so that it is roughly 1-1/2 inch longer than the second clevis cable end hole (Photo 12). Cut the cable, slip the crimp onto the cable, and then slip the end of the cable into the cable end hole. Use long-nose pliers to take up the slack in the cable, and then fold the cable over. Remove the clevis from the bracket and use the swage tool to squeeze the crimp as before. Loosen the locknut and adjust the clevis so that its pin just reaches the bracket’s hole. Reattach the clevis and move to the next cable set.

Materials Needed

• Sullivan 4-40 clevises
• Sullivan clevis tool
• Du-Bro 4-40 threaded cable ends
• Du-Bro crimps and/or Balsa USA crimps
• 1/4-scale Deluxe Nicopress Starter Set (approximately 25 feet of 0.030-inch cable for this 27.5%-scale Nieuport)
• Steel landing gear attachment straps
• Long-nose pliers

Photo 13 shows the right landing cable attached to the top of the front right cabane strut. This will go into the second hole on the bottom of the V-strut bracket. In Photo 14 are the two landing wires attached to the bottom of the V-struts. The front cable is the drag cable attached to the bottom of the firewall. The two flying wires (Photo 15) are attached to the top of the left V-strut. Photo 16 depicts the attachment of the left flying wire (background) and the left drag wire at the front of the picture. In Photo 17 is the left aft flying wire attachment at the fuselage side. The Sullivan clevis tool (Photo 18) makes attaching the rigging wires to the attachment brackets so easy. In Photo 18A, both the Balsa USA (bronze) crimps and the Du-Bro (silver) crimps are in place. I find that with the biplane up on a table (Photo 19), getting to the various assembly points is much easier. To make sure that the rigging wires aren’t too tight when they are installed, tape a length of cable on the top wing (Photo 20). This will show whether or not the wing is straight when the cables are rigged in place. There is bound to be a bad crimp or two while rigging your biplane (Photo 21 shows an example). If you do find that you have a bad one, leave it until the rest have been completed then remove the bad one(s) and replace them with new cable sets. In the long run, it saves time and effort.

Bottom Line

That’s it. I find that standard RC hardware works great and keeps the cost down. (Check the prices of turnbuckles if you don’t believe me.) Now before flying, install all of the small clevis pin keepers. If you find any of the cables are slack, simply twist the cable a few times and tighten the locknuts. You’ll be surprised at how ridged your biplane wings become when all of the cables are in place.