Brigand (oz15564)

About this Plan

Brigand. Radio control pylon racer model. For K&B 40 RC engine.

Direct submission to Outerzone.

Update 28/9/2024: Added article, thanks to theshadow.

Quote: "Hesitant about being able to handle a Goodyear racer? Then our Continental 600 pylon racer is just the machine for you. Brigand, by Tom Protheroe.

Aattention all you guys who want to race, but have been hesitant in attempting Goodyears. The Continental 600 Class is bound to be a great success, not only in its own right as a new member in the fast growing sport of R/C pylon racing but also as a stepping stone to the Goodyears. Clubs with marginal flying facilities may find that 600 Class pylon racing will fit into their scheme of things because the ship's larger size makes its take-off run shorter and its landing speed slower than the Goodyear. The fact that 600's don't need a smooth, paved landing strip for take-off and landing makes them adaptable to Sunday flying.

The motivating force behind the creation of the Brigand was the word that the Continental 600 Class would be activated this year. Design development in the 600's is almost non-existent since l could not find a single ship that looked like it which had the speed potential to last out the season.

The design requirements are basically to come up with a ship that resembles a 190 cu in Goodyear race plane with a minimum of 600 sq in of wing and a maximum engine displacement of .40. Common sense tells us it should be light, of low drag, easy to build, and honest to fly. The Brigand fits this bill pretty well. Its speed around the course would have easily qualified it in the top twenty Goodyears at last year's NATS so it doesn't exactly drag its feet.

The extreme low wing position was used for several reasons.. To begin with, I feel better with the fuselage (or dead weight) sitting on top of the wing when pulling all those Gs in a fast, tight turn rather than with it hanging from the tie down bolts of a shoulder or high wing.

By setting the wing and stab with positive incidence, a great deal of wing and stab separation was obtained without running into structural problems of mounting the stab on the fin. This separation allows the elevator to work in clean air, resulting in good, consistent control all the way around. The thrust line runs parallel with the fuselage datum line so the ship has a small amount of built-in down thrust. This seems to hold the nose down and prevents 'ballooning' when coming out of a turn.

The decision to use the CAR (coupled aileron and rudder) system was not a spur-of-the-moment idea. The system not only saves weight and space but also makes the ship available to flyers with three channel proportional sets. The only characteristic of the CAR system that concerned me was an occasional snap roll, ending in disaster. This situation was related to me by one of the top racing pilots here in Southern California, The condition is the result of over-correction when coming out of an over-controlled turn at No. 1 pylon. (Any ship banked past 90° for a turn will head for the ground when up elevator is applied.) In order to correct this, level the wings with opposite aileron and up elevator. The CAR system also throws in rudder. It is the up elevator, combined with rudder that activates the snap roll. (Therefore, it's a good idea to keep the CAR system away from a ship that has snap roll tendencies).

To date, I have been unable to create this snap roll condition with the Brigand. I believe the only way it would be possi-ble is to balance the ship tail heavy and to use extreme elevator and rudder movement.

The most popular gripe in using the CAR system for racing is the fear of having the nose drop too much in a turn and the suggestion that top or opposite rudder should he used to hold the nose up. Unfortunately, very few, if any, of these critics had actually flown the CAR system around the pylons. I don't believe top rudder should be used because the need (?) for it indicates that the ship is banked over too far and the bank angle should be decreased with the aileron control. (Extreme top rudder in a turn with a short span ship could result in an unexpected snap roll).

Most ships use a differential aileron control (more up than down) to compensate for the yaw to the right resulting from the left aileron control. The down aileron causes more drag than the up aileron. Another way to compensate for this yaw is to kick in rudder with the turn to speed up the outer wing. The CAR system does this automatically when the control surface travel of the rudder and ailerons are tuned or adjusted to work in harmony. For example..."

Update 28/9/2024: Added later article from RCME Apr 1970, thanks to RFJ.

Supplementary file notes

Article.
Article (RCME Apr 1970).

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