Payload Questions:

1. Question: What are the dimensions of the water bottles?
   Answer: Any round bottle may be used (tall, small diameter; short, large diameter) as long as it is labeled by the manufacturer as a 1 Liter bottle. Square, oval, oblong, rectangular bottles are not allowed.
2. Question: Can one use standard water bottles from the store, for example an Evian bottle, as long as it is a 1 Liter round bottle?
   Answer: Most likely, no. Water bottles must be polyethylene (a milky colored fairly soft plastic), most "store" water bottles are polystyrene
3. Question: Are wing pods for carrying the cargo permitted? Is removal of the pods for empty flight a modification to the aircraft structure?
   Answer: Wing pods may be used for carrying the payload. The pods may be removed to change payload, but must be installed (empty) during the no payload cruise/ferry task.

Cost Formula Questions:

1. Question: The battery voltage in mentioned in the published rules is 1.2V. Is it allowed to use batteries with a different voltage?
   Answer: The 1.2V used in the cost formulas is a "typical" value for a NiCad cell under load (it would be higher under no load, and lower under high loads). All aircraft must use NiCad batteries. The actual circuit voltage will vary depending on the actual load at any time. The "nominal" 1.2V value will be used for the cost formulas.
2. Question: The engine power model assumes a current of 50A in the computations. If a fuse of 40A is used in the circuit can that value be used in the cost computation?
   Answer: No. Like the 1.2V value, the 50A value was selected for the cost model as an arbitrary current level typical of model aircraft propulsion systems. The 50A value must be used in the cost model. Teams may determine the actual current levels they operate at based on their particular components capabilities and reliability.
3. Question: In the cost formula the REP equation contains both the number of engines, and the number of cells. How are multiple engine REP's computed?
   Answer: The REP is computed for each engine multiplied by the number of cells powering that engine. The individual engine REP's are then summed for the total REP. For example: (1) If there are 2 engines connected to a single 20 cell pack, the REP would be
   2 engine*50A*1.2V*20 cells
   (2) If there are two engines each connected to a separate 14 cell pack, the REP would be
   1 engine*50A*1.2V*14 cells + 1 engine*50A*1.2V*14 cells.
4. Question: Are the initial cost for set-up per span or per semi-span?
   Answer: Per span.
5. Question: Is a flying wing considered to have a fuselage?
   Answer: It has a fuselage if any body portion extends beyond the "natural" planform of the wing. That includes a "squashed" cross-section nacelle or boom if the resulting section through it is not an "airfoil", and if there is a clear chord length "jump" to the body region.
6. Question: Does the length of the fuselage or pod extend through the wing chord?
   Answer: If an individual body (be it fuselage or pod) extends both ahead of and behind the wing planform, the length across the wing chord is included, as the body length is from the leading to trailing end of the body. If a body exists only ahead of or behind the wing planform, but not both, the length of the body is that length beyond the wing planform (and the area over the wing planform is considered to be a fairing).
7. Question: Where is the line drawn between a bump on a wing and a pod?  For instance, what are mostly embedded engines, unfaired motor mounts, and faired, externally mounted servos considered?
   Answer: A wing mounted nacelle/engine (faired or not) or boom is a pod, as is any other wing mounted structure that extends outside of the basic wing planform (i.e. ahead of the leading edge, behind the trailing edge, or spanwise beyond the wing tip profile when the high lift devices are retracted). The length is that portion of the pod (including a spinner) that extends beyond the wing planform. Servo fairings are not considered a pod if their footprint lies entirely within the wing or fuselage surface.
8. Question: Where do V-tails fit into the cost/ complexity formula?
   Answer: A "V" tail would be the same as one horizontal plus one vertical. It is still two separate surfaces that need to be manufactured. The area of a horizontal is usually greater than a vertical which is the reason for the greater "cost" in the formula. The additional rigging complexities of the "V" tail justify it having the same cost as a conventional horizontal plus vertical tail.
9. Question: How is a flying wing with a single vertical still considered in the empenage cost formula"
   Answer: It would be "charged" with a basic empenage cost, and a vertical tail surface cost. There would be no cost for a horizontal, since it doesn't have one.
10. Question: Are winglets taxed under the cost/ complexity formula? What about aerodynamic biplane struts and wing braces or multi-surface wings?
    Answer: A winglet (or tip sail) is included in the projected area of the wing as if it was folded down flat and added to the span of the wing, but is not treated as a separate surface (i.e. a wing plus winglet will be computed as only one "wing", but with a larger total span). Interplane struts are not included in the cost (we can't think of everything teams may want to try!). Multi-surface wings are treated as multiple wings with the exception that slats/flaps are considered part of the main wing.
    
    The projected wing area is the projected area of each "wing" taken individually. For example, a biplane will have 2 wings, each with it's own projected area. For wings or wing panels with any type of extensible high-lift device (Slat, FCK, VCK, Flap etc.) the wing projected area used will be at the high-lift device setting which causes the greatest projected area.
11. Question: Just how big can a canard or horizontal be before it is considered a wing?
    Answer: If there are multiple flying surfaces, and there is no overlap between the surface, the largest area one is considered a wing. If the "other" surfaces have a high-lift system, they will be considered to be a second (or third) wing.

Flight / Mission Questions

1. Question: The rules state the aircraft must have the wheels off the ground in 100 feet. Is there any height requirement?
   Answer: No, the rules are correct as stated. Aircraft must have ALL wheels off the ground by the 100 foot line, and they must remain off until the landing. Their is no "obstacle" height requirement for this year.
2. Question: Can the battery pack be changed out or "topped off" between sorties?
   Answer: No. Only payload may be unloaded and reloaded. Batteries may not be recharged.
3. Question: Is there a minimum altitude for flying the course?
   Answer: No. Altitude must be high enough for safe flight as set by the discretion of the Contest Director.
4. Question: How are the turns made, and is there a set turn radius?
   Answer: The turns may not be initiated until the turn judge raises his flag (for the two 180 degree turns), but may then proceed to be any turn radius and rate the aircraft is capable of. The 360 degree turn can be initiated anytime the aircraft is on the "downwind" leg and also may be any turn radius and rate the aircraft is capable of.
5. Question: Is it safe to assume that if the rules do not explicitly forbid something, it is allowed?
   Answer: The rules are intentionally designed to not impose too many limitations while allowing each team an equal chance. If something adheres to the "spirit" of the rules it is likely to be allowed. If you have any specific questions you would like clarified they may be addressed in a private e-mail to the contest administrator. Ideas will not be disclosed to other teams if they represent a legal and innovative approach. If it is deemed to be not legal, it may be added to this FAQ or posted to the other teams at the administrators discretion.
6. Question: If the aircraft runs off the runway but is not damaged, can the ground crew help retrieve it?
   Answer: If the aircraft runs off the runway, the ground crew can go to retrieve it once it has stopped. If the aircraft is undamaged, they will return it to the runway to taxi back. If it is damaged and is unable to taxi back, the ground crew may carry it back and make repairs.
7. Question: Where must the "minor repairs" be made?
   Answer: Repairs must be made on the starting line if the plane is to be eligible to make an additional sortie within the "10 minute" time period.
   
   Repairs for the "30 minute" rule may be made at the teams pit, but must be clearly "repairs" not getting out another airplane. You can't change out the fuselage, wing or empenage with new parts, you must repair the "flown" primary airframe structure. Systems (radio, servos, propulsion) and secondary airframe structure (landing gear legs, wheels) may be replaced and qualify for the repair rule.

General Questions

1. Question: Can there be thrust vectoring via rotating the engine, nozzles, blown surfaces etc.?
   Answer: Yes. Any of the above options is allowed, and may be varied during flight. However, "rotary wing" vehicles are not allowed, so you may need to consult the judges with your specific design and it's thrust levels to be sure it doesn't cross over the line into vertical flight capability.
2. Question: What is a sortie and what is meant by multiple sorties may be flown?
   Answer: For this years (99/00) competition there are two different sorties, a payload sortie and a return/ferry sortie. Only the payload sortie adds points to the flight score. The return/ferry sortie is required between payload sorties, and provides an additional and different design point. Teams may complete as many cycles of theses "sorties" as possible within their given 10 minute competition time period.
3. Question: Do all of the team members need to be student members of AIAA?
   Answer: Since the DBF is part of the AIAA competitions sanctioned by the Student Activities Committee and the AIAA Foundation, all team members should be student members of the AIAA.
4. Question: What was the maximum number of people that can make-up a team.
   Answer: There is no specific limit on team size. It is up to the team itself to determine a size sufficient to meet the required tasks and small enough to remain manageable. It is expected most teams would fall in the 5 to 10 member size range, but this is only an estimated guideline.
   
   There is a maximum size of the flight crew (pilot and assistant) and ground crew (3) for this years competition. Please see the RULES section for more details on the limitations on the flight and ground crews.
5. Question: Is it necessary to list all team members on the entry.
   Answer: Yes, we need to know all the team members to verify the under/upper classmen rule.
6. Question: What is meant by "Upper and Under Classmen"
   Answer: Upper Classmen are (for purposes of the contest) seniors and/or graduate students. Lower Classmen are Freshmen, Sophomores and Juniors.
7. Question: Is it allowed to have/declare more then 1 pilot in a team (in case one of them can not go to the contest, or simply have a back-up pilot)?
   Answer: Yes, teams may register multiple pilots as long as each meets the requirements listed in the rules.
8. Question: Can we have corporate sponsors? If so, can we put their logo on the UAV at any place that pleases them?
   Answer: Teams may solicit and accept sponsorship in the form of funds or materials and components from commercial organizations. All design, analysis and fabrication of the contest entry is the sole responsibility of the team members.
   
   Sponsor and university decals or logos may be placed as desired. Teams should make sure that the final color scheme of the aircraft provides good visibility of the aircraft location and orientation for the pilot.
9. Question: What is COB in the submission dates mean?
   Answer: COB - Close of Business: data must ARRIVE by 5 PM local time at the specified location.
10. Question: When will we receive information of the exact contest location, housing options, and the contest day schedule?
    Answer: Detailed contest location and schedule information will be sent to the teams by January 1999.
11. Question: The contest day is graduation. Is there any possibility of moving the contest.
    Answer: In selecting the contest date we have tried to minimize the conflicts with graduation, finals, mothers day,... We can't miss all possible conflicts as each university is on a slightly different schedule. Moving the date earlier would greatly increase the risk of unacceptable weather, and further shorten the time available to design and build the entries (which will seem VERY short by then).
12. Question: We were wondering if it wouldn't be easier to just send an official representative from the competition to our school, fly our plane, and take down the score. Then compare with all the other schools competing(they'd probably be on home turf as well), and make the final decision that way?
    Answer: The single site -vs- fly-at-home issue was discussed much by the contest organizers prior to selecting the current contest structure for many of the same reasons you raised. We realize that it is difficult for students to obtain funds for fabricating an entry, even without the added costs of travel. In the end we selected the single-site format for mainly two reasons: (1) the single-site format will allow the teams to see each others entries and learn from each other and will add to the competitive fever always present when pitting your best efforts against others; and (2) the single site is the only way to assure a level playing field for all entries, as weather variations at multiple sites and days would inevitably help some entries and hinder others.
13. Question: At what wind speed will the contest be called.
    Answer: It will be up to each team to determine whether they want to fly or not. The contest will be called (and the rain date used) if the wind speed exceeds 30 mph for a period of time sufficient to prevent all teams who are ready to fly from being assigned a flight time slot. The 30 mph limit is consistent with normal AMA competitions and is required to retain our contest insurance coverage.
14. Question: Will a hard runway be used?
    Answer: We will select a site that provides a paved runway. Note that a "smooth" paved runway for manned aircraft may still seem "rough" for contest aircraft.
15. Question: Our team has completed our design calculations and we have found a manufacturer that carries wing components that will meet our design criteria. Can we purchase components (i.e. foam cores and skins) to construct the wing for our UAV, or are we required to build it from scratch?
    Answer: You may use unassembled components such as wing cores providing they are integrated in a way that results in the final configuration being an original design.
16. Question: Does the plane have to be an external propeller plane, or can it be a duct fan UAV?
    Answer: Ducted fans are also legal if they use a commercial fan assembly.
17. Question: In terms of propellers. Can they be any kind of Gas engine propeller if we wish? Or do they have to be Electric motor propellers? And if we can only use electric motor propellers, can we cut them? Basically, if we wish to, can we use any kind of non-electric motor propellers if they are commercially available?
    Answer: Any commercial propeller for either gas or electric models may be used. Props may be cut to reduce their diameter but the blades may not be reduced in thickness (such as by sanding the airfoils to a new profile) or in chord (such as by trimming the trailing edges).
18. Question: What constitutes "over the counter" batteries, and does this apply to the battery pack or to the individual cells?
    Answer: The "Over the Counter" refers to the individual cells. This is a change from the rule for the 1996/97 contest year.
19. Question: Could the electricians in the Electronics Shop at our university build the battery pack, since they are licensed electricians?
    Answer: Yes, as long as they use commercially available cells.
20. Question: Do you have a vendor list for speed controller and/or gear reduction suppliers?
    Answer: The "MOTORS" and "ACCESSORIES" sources listed on the web site vendor page can supply controller and gearbox sources that are suited to their motors. Other sources would include all of the major hobby part suppliers listed in RC magazines.
21. Question: How is the radio fail-safe described in the safety supplement to be implemented.
    Answer: This is a feature available in many production RC radio systems. It is required that your radio system be able to provide this function.
22. Question: Can we construct a composite can for an otherwise stock over the counter model motor?
    Does the motor controller have to be an over-the-counter controller?
    Answer: The motor and/or controller must be an unmodified commercial product. The intent of this rule is to prevent excessive cost, and to provide all teams access to equal propulsion technology so they can concentrate on the aircraft aerodynamics and structural aspects.
23. Question: Do the wires and connectors have to be commercially available?
    Answer: Yes
24. Question: When you check the CG, what kind of a point will you use? For example will it be checked with fingers or dowels or something even sharper?
    Answer: The CG check will be coincident with the structural verification test described in the Safety Requirements supplement to the basic rules. Specifically, two team members will be asked to pick the aircraft up by the wing tips using their hands (usually a clenched fist placed under the wing at the desired location works well). They will (gently) lift the aircraft at it's full contest weight by the wing tips at the marked axial CG location.
25. Question: Will the payload be supplied by the team or the contest administration?
    Answer: By the team.
26. Question: If battery power fails can an immediate landing be made without making a complete lap (question paraphrased by editor)
    Answer: First priority is safety of personnel, followed by minimizing damage to equipment. If power fails unexpectedly the pilot will setup for as safe an emergency landing as possible. If the plane does not pass the downwind pylon that sortie's payload will not count, but any prior sorties will still be credited toward the overall score.
27. Question: Will there be a maximum altitude, other than the visibility requirement?
    Answer: There is no specific numerical altitude limit. It would be very difficult to enforce a rigorous altitude limit without altitude telemetry equipment on each aircraft which would be a significant expense burden. The contest flight judge will enforce maintaining a "safe" altitude for both personnel/ground and flight visibility reasons, and may order the pilot to descend if he feels the altitude is too high. In general, altitudes of 300 to 500 feet are probably nominal, and altitudes near 1000 feet are likely to have the judge order a decent.
28. Question: Is information available about previous year designs and results?
    Answer: A summary of characteristics for all the entries that competed in the last years contest will be available on the contest web site. Remember that the objective of the prior years contest was slightly different, so you will have to adapt the design data accordingly. (Prior year rules will also be maintained on the web site for reference.)
29. Question: Would we ever have to make any vertical loops with the UAV?
    Answer: No

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