Piper Twin Comanche (oz8060)

About this Plan

Piper Twin Comanche. Radio control twin sport-scale model.

Quote: "5th place Internats scale winner Joe Bridi presents the sport scale ship he flies for fun. Piper Twin Comanche, by Joe Bridi.

As with most scale models. general information and details are hard to obtain. You can spend many hours, weeks and even months, researching a suitable aircraft for scale modeling. Accurate three-view drawings, of an approved source, is a must; cabin or cockpit details, landing gear and wheels, finish, etc, are all equally important when attempting to choose and build a scale project.

The Piper Twin Comanche was picked in this case because of its availability at the local airport. I was able to obtain suitable three-view prints from the local Piper dealer and, having the actual aircraft in the area for reference, I could take photos and refer to the aircraft for details whenever it was necessary.

The model itself worked well for construction purposes. Its clean design and attractive colors for paint-ing and trimming has made this scale model eye-appealing in every way.

We will be going into some of the construction details that were used. We did deviate from scale in certain areas to speed construction time and also make the model more eye-appealing. If we were to give a percentage of accuracy for this model, I'd say it would be 75% scale.

Wing. The wing construction on a scale twin engine of this type is the engine mounting platform type. The original Comanche was built with Styrofoam wing cores. This speeded up the construction time a bit. We've detailed all of the ribs separately in case you would like to make a built-up type. If you wish to cut a foam wing use only the ribs necessary to cut your core. The foam wing was planked with 1/16 balsa and had a full trailing edge of balsa for reinforcing. The land-ing gear was attached in regular class C manner. The flaps were also used as per scale.

The engine pods were made of solid balsa block epoxied to the wing followed by 1/2 inch leather fillets. The engine nacelles were vacuum formed from plastic, although they can also be made from fiberglass; this is not too difficult, since the nacelle is carved and shaped with the pod and you already have the making of a mold for this purpose. Simply cut the nacelle for use as a male mold if desired. The engines were radially mounted on removable fircwalls for easy access to the fuel tanks with all venting done inside the nacelles. themselves. Careful construction tech-niques are required on the engine mounts due to twin engine vibration. A twin seems to go in and out of harmonics and this sets up a tremendous vibration.

Fuselage. The fuselage was made narrower than scale for improved appearance. The construction is both standard and easy. It consists, basically, of two large sides, which are brought together in the front with top and bottom blocks glued together similar to the old Stormer construction. The frame around the windshield and windows is 1/16 plywood and is installed early in the construction stage, and before the top cabin block is glued into position.

All of the cabin details will have to be finished before scaling the cabin. This includes the side curtains, seats, dash, carpet and headliner, all of which are completed while still constructing the fuselage.

Stab and Rudder The actual stab on the larger air-craft is in one piece, but we chose to use standard R/C type construction here of the fixed, and more conven-tional, style. If you plan on entering scale competition and want to place high on the list, I suggest you obtain the three-views and re-do the stab to scale configuration.

Painting. Before painting the Comanche, check with your local Piper dealer as to various colors and trims. Colored photos can also be helpful and are often available. The original model was painted with acrylic lucite, with the colors available at auto paint supply stores by factory code numbers. I would suggest checking into the acrylic material before using - the Comanche, after 4 years of usage,
shows check marks and splits in the finish.

Test Flying Here's where the fun begins! The extra engine should be considered a LIABILITY instead of an asset. Absolute reliability with both top rpm and idle is a MUST! The two engines you employ have to be tops in all ways. I used 2 Merco 49's with Fox 59 carburetors. To date, I have at least 60 flights and only once did I lose an engine. This was also a surprise to me, since I had lost the engine at high speed, and I was able to control the model with only slight aileron correction. I have flown a few other twins and they can be a barrel of snakes with only one engine working..."

Supplementary file notes

Article pages, text and pics, thanks to Cavitation.

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