Thomas Morse Scout S4C (oz10800)

About this Plan

Thomas Morse Scout S4C. Wingspan 64 in, wing area 1347 sq in. For OS .90 2-cycle engine. Scale is 1/5.

Note this 3-sheet plan is available online as a free download from the designer himself at http://www.mnbigbirds.com/Andersen%20Plans.htm where there is also an excellent 13 page construction manual, including notes and colour photos, available as a free download.

The plan was also published in Model Aviation, June 1991 issue, see http://library.modelaviation.com/ma/1991/6/1

Quote: "How about a little period flying? This jazzy-looking 1/5-scale rendition of a Roaring Twenties biplane is the perfect aircraft for trying out the Chandelle and other exotic, once-popular maneuvers you've probably never heard of. Powered with an 0.S. .90 two-stroker, the model combines aerobatic agility with the gentleness of a trainer. Thomas Morse Scout S4C, by David P Andersen.

During World War I, American pilots were trained in lumbering Jennies and Standards, then expected to fly nimble Nieuports and Spads in combat in France. This training gap was closed in 1917 by the Thomas Morse Company of Ithaca, New York. The Scout S4C was America's first advanced fighter trainer. While some have called it the AT-6 of World War I, it actually was produced too late to have any significant effect upon the war. Orders for 1,050 of these biplanes were canceled at wars end after 497 had been delivered. Nearly all were sold to the pubic and the S4C was widely used throughout the Twenties both as a private airplane and in flying schools. Many of the apparent Sopwlths in movies such as 'Wings' and 'Hell's Angels' were actually Tommies, just as AT-6s were used to simulate Japanese Zeroes after a later war.

With its gentle trainer qualities and aerobatic agility, Tommy was a delight to fly. Those are precisely the qualities we look for in a vintage RC Scale model. I decided on the following design objectives for the Tommy:

- The model would be 1/5 scale.
- Engine: O.S. .90 two-stroke with O.S's swing muffler.
- Shock-absorbing landing gear.
- Must fit in a subcompact car with the wings intact.
- Can be built with inexpensive materials and tools.
- Scale accuracy good enough to win Sport Scale contests; adaptable to FAI Scale with the addition of surface detail.

All the documentation you'll require to compete in Sport Scale is included in this article, and additional references are supplied.

The S4C is a delight to fly. Since it's a trainer, ground-handling and stability are superior compared to World War I fighters, yet it has the look of a Camel engaging the Red knight. Still, the Tommy is less forgiving than the typical nonscale sport airplane, so only experienced builders and seasoned pilots should consider it.

if you'd like to return to the romantic years of the Jazz Age, pull up the sheepskin collar of your leather jacket, wipe the oil off your goggles, and come on down to your workshop. Break open a mason jar of bootleg hooch, put a scratchy old Bix record on the Victrola, stack the balsa, and get ready to start cutting. This will be one of the most enjoyable airplanes you've ever built, In fact, it's the cat's pajamas!

Would the Red Baron bounce? The idea of using a coil-sprung landing gear in this model occurred to me while flying a fifth-scale Fokker Triplane. Its gear was similar to the type used here, but the struts were rigid. You'd hear a shuddering clunk as the unyielding gear hit the ground.

I expected the forward strut to buckle from this abuse to my surprise, the aft strut bent instead. Apparently the rearward landing force is greater than the upward force. Since the forward speed of the airplane is greater than the downward speed, this stands to reason. Why, then, did full-size airplanes of the era have axles that allowed only a small amount of upward travel? The answer lies in their slow landing speeds - only six miles per hour at fifth-scale equivalence. Since our models must land faster than that, greater rearward shock absorption was needed.

My solution was to allow the forward struts to swing backward and slightly upward by attaching them with J-bolts to the firewall. The rear struts have coil springs inside the fuselage, anchored in plywood bearings in the middle of the fuselage sides. The springs will compress on landing, allowing the axle to rotate rearward and upward (mostly rearward). Play in the rear struts is achieved by cutting small openings at the point where they enter the fuselage. This provides a good tolerance; a rearward throw of over two inches is possible before damage will occur. Compare this with an upward-only throw of only 1/2 in and no rearward motion whatsoever if scale shock chords are used. Touchdowns are silent, obviously cushioned, with little tendency to bounce..."

Update 31/10/2023: Added article, thanks to rocketpilot.

Quote: "Attached is the complete article for Dave Andersen's Thomas Morse Scout. An outstanding model and great flyer. I had built it many years ago, and just found out, it's on its fourth owner, and is currently undergoing a restoration. Thanks ever so much for all that you both do. Have a great day,"

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