Questor Specifications
Bill's Project Notebook


Questor is the project name for a new modular model airplane that can break down easily for transport. The design must meet the following requirements:

  • Airframe must accommodate an O.S. .26 4-stroke engine, modified for diesel, with generator
  • Airframe must carry a fully-integrated lighting system for night flying - also to double as a power regulator for charging on-board batteries
  • Lighting system shall have a Hi/Low power setting (6 LEDs always on in the tail, 21 additional LEDs in wing and fuselage for high power setting, 9 for low power setting). The low power setting will allow available residual power to be supplied to other on-board device(s)
  • Wing must separate into two sections, divided at the root, joined together by a spanning support beam or tube
  • Wing joiner must attach to one wing in such a way that its removal requires a conscious effort
  • Wing will be bolted to the fuselage using nylon bolts
  • Fuselage will separate from the tail boom
  • Horizontal and vertical stabilizer, complete with elevator and rudder controls, must be individually and completely detachable from the tail boom
  • Of the tail section, only the horizontal stabilizer is required to have lights (LEDs)
  • Horizontal stabilizer must have one LED facing forward on each side that is visible directly from the face of the aircraft
  • Wing will contain nine (9) LEDs in the high power circuit in each of the two wing sections. One LED in each section must point forward to be visible directly from the face of the aircraft. Three (3) LEDs in each wing section must be in the low-power circuit, one of which (in each section) must face forward
  • Tail boom will carry power wires from the fuselage to the tail for LED power. Each end will have a connector that plugs into receptacles on either end to complete the electrical connection. Power wires will be embedded permanently within the tail boom with connection points on the tail end for soldering. The fuselage end will have a female connector permanently embedded within the boom end, with a mating male connector embedded in the fuselage at the receptor end
  • Any external electrical connectors in the tail must be housed in a protective encasement that prevents exposure to fuel, moisture or potential disconnection while in flight configuration
  • Mating of electrical connectors between tail boom and fuselage should require no additional effort beyond what is required to attach the boom to the fuselage
  • Mating of electrical connectors between tail boom and lighting circuit in the tail section should require no additional effort beyond what is required to attach the tail to the boom (i.e. the act of mounting the tail should result in an electrical connection)
  • With the exception of the wing mounting bolts, no mounting pins or other apparatus may be completely detachable from the airframe or require the use of tools to secure or detach
  • Landing gear must be conveniently detachable from the fuselage without compromising its function!
  • Wing segments must not exceed 28 inches in length when detached and separated
  • Fuselage segment must not exceed 28 inches in length from the tip of the spinner to the rear of the fuselage when detached from the tail boom
  • Tail boom must not exceed 28 inches in length, including any protruding control rods, when detached from the fuselage
  • Fuselage will carry engine, generator, fuel tank, receiver, servos and batteries as a self-contained unit
  • Tail boom will carry servo control rods between fuselage and flight controls and should use ball links at all connection points
  • Fuselage must provide a lower cargo region for carrying devices or instruments that can operate on power provided by onboard generator and batteries
  • Cargo area may have servo-controlled hatch door that can be used for dropping items from the aircraft while in flight
  • Complete airframe must be as light as possible, preferably not to exceed 4.5 pounds when fully equipped but with no cargo


I have thus far failed to consider, or have encountered difficulties in implementing, the following and must make accommodations to correct:

  • 27 LEDs were selected for the high power lighting circuit, but the low power circuit was neglected. Six (6) additional LEDs must be selected for the low-power circuit
  • The electrical connector between the tail boom and the horizontal stabilizer was affixed nearly 1/8 inch too far forward. This had to be corrected before any further development could take place.
  • Flexing the booms into place as they eventually will need to be affects the width of the gap created for the fin tab. A jig was needed to hold the boom in near-proper configuration before work on the tail section could resume.
  • Incomplete design for attaching the tail fin resulted in significant modification of the fin's nose region and possibly affects its overall inherent strength.

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