Sopwith 1-1/2 Strutter (oz16303)

About this Plan

Sopwith 1-1/2 Strutter. Free flight scale model for rubber or electric power. Wingspan 17 in. Scale is 1/24.

Vector format plan.

Note this plan is freely available as a download from the publishers at: http://aero-modeller.com/online-content-for-aeromodeller-944/

Update 1/10/2025: Added article, thanks to Eric, Maciej.

Quote: "Free Plan. A Simple Strutter. 1/24 scale free flight design by Richard Crossley.

When I designed this little job I had in mind the many Keil Kraft and Veron small WWI scale rubber powered models that I built as a kid. The structure of this ‘Strutter’ is similar to those old designs, but I have tried to remove a few of the problem areas that confronted me - namely the intricate wire bending, which was an absolute pain, so in contrast this strutter is almost wire free! The distinctive cabane struts are from balsa, and a sprung axle means that landing loads are generally light, so balsa gear struts can be employed, saving weight and speeding the build.

There is a drawback with rubber powered models of WWI aircraft - often the original featured a heavy engine in a relatively light airframe, so to get the balance point in the right position they sported very short noses. When modelling this type of aircraft, care has to be taken to keep the rear fuselage and tailplane as light as possible, otherwise a hefty lump of dead weight will need to be carried along up front. However, the Strutter, along with other 2-seaters of the era has the extra weight of an observer or gunner situated behind the trailing edge, meaning the engine is mounted further forward on a longer nose to compensate, and a lighter, happier scale model results.

The elegant Sopwith 1½ Strutter first flew in late 1915, making building this model a fitting centenary celebration. It was a multi-role aircraft, and notable for being the first British designed ‘tractor’ fighter, and also the first British aircraft to enter service with a synchronised machine gun. It got its name from its unusual cabane strut layout - there was no conventional centre section, each of the upper wings was connected to the fuselage by a pair of long and a pair of short (half) struts. ‘Strutters’ were built in a number of configurations, there were single seat bombers, with the rear cockpit faired over hiding an internal bomb rack, there were also single seat fighter versions, some with the pilot sitting in the rear observers position.

It was eventually withdrawn from service in late 1917, and replaced by the Sopwith Camel. Surprisingly, of the almost 6,000 Sopwith 1½ Strutters built, 4,500 were built in France and served with the Aeronautique Militaire. I modelled my ‘Strutter’ in French markings as I liked the contrast of those big colourful roundels on the warm glow of natural linen.

My Strutter was designed to fly in my local sports hall in Stalham, Norfolk. I needed something that would float around indoors in relatively small circles. At 1/24 scale it's entirely practical outdoors too in the calm. I have shown a lengthened landing gear on the plan for ‘ROG’ so that an oversize 6 inch prop can be accommodated for maximum duration. If you intend to fly outdoors only, or use electric power, you may wish to choose the scale length landing gear.

I have described an electric installation using the Atomic Workshop Zombie speed controller, 90mah LiPo-cell and Voodoo 15 motor, (or Voodoo 25 if you build heavy! - they are both identical externally). The model would fly superbly with this set up, and would be considerably lighter than a rubber model. You can find Atomic Workshop at www.atomicworkshop. co.uk, or call Jonathan Crossley on 01493 369317 (yes, my brother!)

A quick note for those interested in indoor scale competition, this plan would make a good basis for an indoor competition model. It could be scaled up slightly and a bit more structure added here and there as desired (1/20th scale would put it just over 20” span). It is fairly accurate in its basic outline. The wing plan show position of scale rib spacing.

Building Notes: Simple models like these can be built with a limited amount of resources. I use a small piece of blue Floormate 25mm thick foam as a building board (easy to push pins into) and do my building on the coffee table in the living room with the family. Other things you will need are a small A4 cutting matt, Swann Morton Scalpel with a 10a blade, pins, sandpaper, steel rule for cutting straight lines (I always cut my own stripwood), and your favourite glue.

For me Esaki tissue is the only way to go when it comes to covering. I use it shiny side out, gently watershrink (steam shrink for the tail feathers) and complete the fi nish with one or two coats of thinned dope or banana oil.

The Strutter will not prove at all challenging for the modeller who has previously built a couple of scale designs. The plans feature lots of information and tips, and together with the captioned photographs should provide all the gen you need to make a cracking job. I have set the model up with 2 degrees of incidence on both wings, which makes it a stable performer, no washout is required. Note the added dihedral which allows the model to turn quite tightly in my relatively small flying hall (scale dihedral may work fine outdoors).

Carefully cut out all of the parts. For the wing ribs make a simple ply template and use this as guide to cut around. This ensures all ribs are pretty much identical. You can then pin together the ‘block’ of ribs and cut the notches using a modeller’s file. Don’t worry about those fiddly looking cabane struts..."

Supplementary file notes

Article.

Corrections?

Did we get something wrong with these details about this plan (especially the datafile)? That happens sometimes. You can help us fix it.
Add a correction