I think QUESTOR was a precedent version of SUPER QUESTOR oz5836, with a small span of 62", constant chord wing and vee dihedral. I could not find the original plane (and the box neither), but taking measures on my model I have been able to verify that the rest: tail and fuselage, are exactly the same. The two wing panels, with a washout of 3mm each, are joined by a bend rod of 4mm.
More than 25 years ago I won this kit in a thermal contest, flying a similar model: Graupner DANDY oz4538. Then I was not interested, but I built the QUESTOR and I put it on sale. It was several years hanging in the showcase of a local models store, but no buyer was ever interested either. Recovered some years ago and having small size servos and Rx, I equipped it to fly.
QUESTOR is similar in size to the mentioned DANDY (62" vs. 63" span) and on purpose, although in design is something simpler. With a measured weight of 547g I feel that the thermal flight characteristics are slightly poorer than the DANDY's and in the slope the penetration is similar; that is, nothing extraordinary!
Thus, the advertisement "High Performance RC Sailplane" on the box label seems a bit exaggerated for a model of this size. Instead, in the Airtronics publicity in the magazines of those years, it was presented as "Compact Size RC Sailplane". It also mentioned the wing airfoil as "E-385 flat bottom", which in my opinion was more a publicity issue than a practical aerodynamics question. The true Eppler 385 airfoil was in fashion and widely used in super-floater sailplanes in the '70s. It is highly cambered (5,3%) and 8,4% thick, thus its height lift has nothing to do with the fully flat used, more taking into account the sharp leading edge, also in fashion in the '70s sailplanes.
Well, today I'm using QUESTOR as a school model, replacing my beloved old DANDY that was lost inside a cloud. Glory to both models!
Joan (John) Brunet, Tarragona, Spain, February 2018