Mercy! Mercy! That Dang Nabed PERCY!

Old-School versus New-School

Old-school versus New-school

I have this old 1/4 scale model of a Piper Cub I found in the backroom of a hobby shop, in Marshfield Wisconsin. It was built from a kit, albeit an old one. It’s forty years old if a day. I'm not even sure it was ever flown because the flight surfaces appear to have never been hooked up.

In the old school of early RC model flying the protocol was generally to put the servos in the belly of the airplane beneath where the wing attached. A long dowel rod was used extending back, to provide linkage for the rudder and aileron.

Since it’s a big model the servos have to exert some energy and there were some flex problems I encountered when bringing my rehabilitation efforts up to date. Further, where the wing halves join, was this huge space for one of those oversized Futaba monstrosities that used a long metal rod down both wings to make the ailerons work in opposition to one another.

These linkages are buried in the wing and rusted and the new servo I bought can’ t be mounted on its side like I think the old one was. (The servo bay was empty when I acquired the model, however the telltale screw holes offered evidence to what had once lurked inside.) Thus, there is no way I intend to hook it up the way the original builder envisioned.

In the progressive school of RC model building the servos are smaller and often located as close as possible to where they do their work. For example it is not unusual to see the servos located well aft for the rudder and elevator. This overcomes the flex problem and need for long wooden dowels or sliding sets of plastic rods and thick threaded wire. The same is true in the wings. The servos are commonly well out on the wing and centered close to the aileron they are intended to operate. After trying to make my new servo work as the original builder intended, there was a change in plans. I’ll be using two, one in each wing half.

Concurrently I'm trying to get a couple of airplanes ready to fly Sunday for the picnick, and build this new trainer I bought at the Fond du Lac War-bird show.

I tend to be impatient and the salesman who sold it at the show price, told me to take my time building a model from scratch. Actually a kit isn’t building from scratch. A true scratch build might begin with a photograph, however, at least having a plan is more common. So I have resolved to go slowly and do a couple steps of instruction each day. The model is well thought out. It uses a 40 size glow engine and everything is more accessible than is normally the case with a trainer. There is no cowling, the gas tank sits exposed behind (held in place by rubber bands) and the linkages to the rear flying surfaces are exposed. I started with the bottom, set the fuselage stringers, the hardwood motor mounts and the plywood floor. The motor I intend to use, an OS 40, dropped right in. I’ll keep all my interested readers () abreast on how the build goes.