F-9 (oz9341)

About this Plan

F-9 . Radio control pattern plane, for Super Tigre 56 power.

Quote: "The F-9 was designed strictly as a contest ship, and since each person has his own personal likes and dislikes, I hope it will prove to have a little something for everyone.

Personally, I have always preferred a high wing loading, because it allows the engine to idle faster with a steeper landing descent, which makes it easier to hit the spot. After building several small airplanes around regular engines, it was decided that the larger models fly more smoothly, but the only way to get the Vertical Eight was with a bigger engine. The F-9 was built was a .45. No effort was made to build it light, and you will notice it has a full length 1/32 in Plywood doubler and 1/2 in ply firewall. You will also notice a large amount of dihedral which takes care of the plane on takeoff, straight flight, and landing. The large vertical fin will hold the F-9 in a normal turn with ease.

The flying tail was designed just to be different, but it has proven its worth in being quite easy to trim and fly. On the first flight I set the flying tail at what looked to be good and level. Later it was measured by blocking the airplane up until the wing was level, only to find it needed more 'up', until it measured level with full up-trim.

Then out to the flying field - alone! If it was to crash, I could do without the - I told you so's. Fly it did, albeit needed even more up. In addition, it proved to be somewhat nose heavy, so clay ballast was added in the jet pipes. (Quite handy).

I like an airplane that is easy to fly during the landing, which means that power-off must not change the trim of the craft. This is accomplished by changing the CG to the rear and adding a little downthrust.

Trimming an airplane is a story in itself and this is simply my approach to the problem. First, I get the airplane to glide both fast and slow with no turn and a nice descent..."

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