Taboo XT home
Taking the best features of the previous design and improving upon it with the help of the new airfoils, better materials, stronger and stiffer structural components, Taboo XL takes discus launch flying to a new level and is one of the best discus launch gliders available today. The new series of airfoils developed by Mark Drela specifically for flapped wings (AG45-46-47) and used on his well-known glider SuperGee give Taboo XL excellent wind penetration qualities and exceptional thermalling ability. The response of the airfoils to increasing camber is very good making the extra weight of the structure and radio gear not an issue even for a 6 servo plane. With a little trailing edge camber the plane floats like a super light polyhedral floater. At the same time the launch height is amazing with the flaps/ailerons in the reflexed position. Taboo XL was admitted by many people to be the highest launching plane at the IHLGF 2002 in Poway.
The airfoils were designed to have two discrete flap positions: speed mode and thermal mode. In each position one of the airfoil surfaces is smooth, thus minimizing the extra drag of the deflected flap in both regimes. In the speed mode (flaps up) the bottom surface of the airfoil is smooth which correlates well with the fact that the lower surface of the airfoil is more critical at high speeds. In the thermal mode (flaps down) the top surface of the airfoil is smooth, which again is the more critical surface at high angles of attack. Traditional airfoils have a sharp surface kink on both sides of the airfoil at any flap deflection angle except zero, which means they have higher drag with any flap deflection. The polyhedral version of the plane uses airfoils AG12-13-14 which are very close to AG45-46-47 with the flap fixed in the cruise position. The minimum drag of these airfoils is very close to the minimum drag of the flapped airfoils AG45-46-47.
Taboo XL is available in two versions - aileron and polyhedral. The aileron version can be built as a 4 servo airplane with flaperons or as a 6-servo airplane, with flaps and ailerons. Shown on the pictures is my 6 channel Taboo XL flown at the IHLGF 2002 in Poway. Full-house setup gives the ultimate glide path control at the cost of a small weight penalty. A 4 servo plane will have the same camber changing ability and the same great roll response, but slightly lower glide path control ability. The polyhedral version of the plane is a good compromise of the flight performance and ease of control. Its launch height is very close to that of the aileron version, while the slow flight performance is the same or better than that of the aileron version.
The construction of the plane is similar to the old Taboo with a few significant changes. The wing uses blue foam and kevlar skins for the ultimate strength and durability. If you have not had a kevlar skin hand-launch glider before, you will quickly realize and appreciate the advantages of kevlar skins. The damage to the wing from normal wear and tear is much lower with kevlar skins, regular dents are smaller in size and are easily fixable using the hot iron and water trick. So your glider will live a longer life now. The wing comes cut into panels, bevels pre-sanded to the correct angle.
Fuselage pod is molded of fiberglass and carbon and has plenty of space for radio installation. There is plenty of room for extra equipment (gyro, battery voltage sensor, etc.), and a good micro switch jack. The pod is mated to the high quality large diameter Allegro tail boom (the boom originally designed for the 2m glider Allegro, one of Mark Drella's designs, well known among the scratch builders). The fuselage requires no work to finish it other than drilling the hole for the wing bolt and tapping it. Fuselage comes with the pushrod guide tubes installed.
Tails are made of contest grade balsa vacuum bagged with light fiberglass on a bias. They require no work to finish them, only mount the stab and attach the pushrods. The fin comes glued to the tailboom. Stab requires gluing to the balsa pylon and then gluing to the tailboom.
Servos are glued to the fuselage bottom with epoxy and micro-balloons. Fuselage was designed to take 300mah NiMH battery (same size as 110mah NiCads), Hitec 555 or Super-Slim receiver and 2 sub-micro servos. A full size Hitec Super-Slim receiver is required for the full-house version.
The full-house plane weighs about 10.5-11.0oz when finished. The polyhedral plane will weigh about 9.5-10.0oz. As I mentioned before, the extra weight of the aileron plane is a non-issue with the great lifting ability of the airfoils, and during the launch the extra weight is only a plus. If you think that an 11oz hand-launch plane is too heavy, you probably have not done a lot of discus launch flying, and you definitely have not tried the new airfoils from Mark Drela. You will be pleasantly surprized with the floating abilities of Taboo XL.