RC Arf Conversions For Cl Navy Carrier

Wooden model airplane interior with wires and compartments.

As seen in the June 2025 issue of Model Aviation.

I’VE PREVIOUSLY DISCUSSED alternatives to the MO-1 in this column. I still believe that there are other models that will perform as well as the MO-1 does, but the ease of building an MO-1 continues to make the design popular in Control Line (CL) Navy Carrier events. Although I have parts cut out for three MO-1s and one nearly complete, I’m backing up my earlier words by producing different models for my next Electric Class II and Profile models. The photos are of my Electric Class II Seafire, which will be flying this summer. I will be resurrecting my Vought Kingfisher design as my next scale-outline Profile model.

There are few kits that are suitable for CL Navy Carrier flying. Most are older and out of production, so finding them is a potential problem. The models of 50 years ago are great for the Nostalgia Navy Carrier events, but are less suited to modern competition than the larger models that are currently in use. The only kit currently in production for CL Navy Carrier is Bill Calkins’ Profile AF-2S Guardian from Brodak. Older House of Balsa kits for the P-51 and AT-6 (SNJ) were the right size at a 43- to 44-inch wingspan, and they occasionally appear on sites such as eBay, but they were not designed for Carrier and require considerable strengthening.

Model airplane fuselage with wiring and wooden supports. — Converted RC models will need a bellcrank mount. This one extends the battery tray to a full 9-1/2 inches to allow for a wide range of balance points to optimize performance.

There are also still a few MO-1 kits for Profile that have not been built, although Jim Hoffman and Lou Wolgast from Arizona have just completed two of the remaining Golden State kits. There really are no kits for Class I and II designs. There are, however, some offerings in the RC ARF category that could be converted for Navy Carrier flying.

Model airplane wing interior with circuitry and mechanical parts. — A strong bellcrank mount consists of 1/8-inch plywood with a 1/4-inch balsa doubler the full width of the fuselage, plus 1/2-inch triangular gussets glued to 1/8-inch balsa fuselage side doublers.

In CL Scale, there have been RC ARF models used with some success, especially in the Fun Scale event. Peter Bauer’s article in the February issue of Model Aviation described the conversion of an RC Bearcat foam ARF for Fun Scale. By the way, the conversion is the work of our own Pete Mazur, who is well known in CL Navy Carrier circles.

There have been, and continue to be, RC ARF warbird options that suit our Class I and Class II events, both for internal combustion and electric power. Fortunately for us, the 1.1-meter class of ARF airplanes is popular because the models are relatively easy to transport. A 1.1-meter wingspan converts to 43.3 inches—slightly less than our 44-inch limit.

There are a few factors in converting an RC model to CL Navy Carrier flying that present greater challenges than a conversion to CL Scale, but they are not insurmountable. The key word in all areas is more. Compared to RC, for which the models are designed, CL Navy Carrier uses more power, more cooling air, more speed, more pull tests, and has more landing stresses. What follows are some of the things that I considered in converting an ARF Supermarine Spitfire to a Seafire for Electric Class II competition.

More powerful (therefore, heavier) engines/motors can usually be handled without significant modification, but you should consider that the greatest stress on the front end of the model might occur in landing. I saw a motor depart an Electric Class I Corsair during the arrested landing because the firewall was not designed for that kind of loading. I added a couple of triangular gussets behind my firewall. I also considered using expanding insulation foam, but I wanted to preserve as many options as I could for battery location.

Model airplane cockpit with transparent canopy on wooden frame. — Electric Carrier models require more cooling than RC sport models. Allow for more intake area, as well as more exhaust area. Opening the canopy provides as much as you want.

More power means less stability, so the balance point won’t be the same as what is recommended for the RC model. You might want to consider enlarging the horizontal tail surfaces within the limits allowed by our rules. If a heavier engine/motor/battery needs to be countered with tail ballast, a solid balsa or basswood stabilizer and elevator can also help while offering some additional strength.

You will need a tailhook or a combination hook/tailskid and will likely need to strengthen that part of the model by connecting the mount area to the sides of the fuselage or another substantial longitudinal structural member. Strengthening the main landing gear might also be advisable, especially on a foam model. You might consider adding a short spar between the gear mounts to spread landing loads across the wing center section if the landing gear is wing mounted.

The greatest challenge of all will likely be strengthening the model to withstand the pull test. What’s appropriate for a Scale model with a 5G pull test will probably not work for a Carrier model with an 80-pound pull test.

The bellcrank mount will be a completely new component, and the pull test will load the fuselage in ways that were never considered by the RC model designer. The bellcrank mount should share the pull test and flight loads with both sides of the fuselage, and the contact points should be gusseted to spread the loading both longitudinally and vertically. Doubling the fuselage sides in the area between the leading edge and trailing edge of the wing should be considered.

Be sure to also consider how you will hold the model for the pull test. This might be especially important for a foam model because you will not want to have the fuselage side custom-molded to your fingers after the first pull test!

You might wish to evaluate the wing mounting on the model. A single piece of 1/8-inch light plywood through a slot in a former might not be adequate for the torsional loading of the line slider—another factor that was not considered by the designer of the RC model.

Not all "Scale" models are created equal in the accuracy arena, so be sure to confirm that your model matches the three-views that you intend to use for documentation. The easiest way to do that is to take your three-view drawing(s) to your local copy center and get it enlarged to the wingspan of the model. All of the parts can be directly compared to the enlarged drawing.

Line Slider Correction

In the December 2024 column, I mentioned that line sliders started being used in Carrier in the mid-1970s. I received a note from Bill Lee shortly after that column was published, informing me that he had a line slider in his Profile Carrier model in Chicago in 1972. He believes that this was likely the first use of a slider (moveable leadout) mechanism in Navy Carrier competition. I stand corrected!

LineMaster Handle for 2.4 GHz

I’ve been communicating with Carlos Diaz about the LineMaster 2.4 GHz CL handle that he is developing. The original concept and prototypes were great, and the improvements he is incorporating into the production handle are many—all are geared to make the production version even better.

I had intended to give an update on the development as the concept moves toward production, but things are happening so fast that by the time this column is published, some of the information might be outdated. The best way for you to see what’s happening from week to week is to go to the LineMaster 2.4 GHz Facebook page. The link is in "Sources."

Meanwhile, keep your tailhook dry!