27 September 2004 Revision
Frequently
Asked Questions (FAQ)
2005 Competition Specific
Please check the FAQ often during the competition. Please note that rules interpretation
questions are not answered by e-mail until after the entry date (when all
participant e-mail address are known), so that all teams will have equal access
to all rules information.
General Notes:
1. Brushless motors are now legal.
- Ni-mH
batteries are now legal. Li-Poly
batteries are NOT legal for use either as propulsion or RC batteries.
- There has been some question of the interpretation of
“spare” parts for repair. “Spare”
parts may include:
·
Any
purchased component, such as: wheels, propellers, motors, servos, control
links, control horns
·
Team
Fabricated spare parts are limited to: landing gear, control surfaces, hatches,
linkages and mechanical actuator mechanisms
All other aircraft components must be repaired, meaning they retain some
reasonable portion of the original, or are completely re-fabricated by the on
site team members using the same materials and techniques as the component they
replace.
Payload Questions:
- Question:
If for the sensor reposition flight we are able to reload only one of the
payloads can we continue the flight?
Answer: No. Letting a plane fly with only one of the two external (or internal) payloads loaded would provide an advantage (and is not provided for in the scoring equations). Flying with only one EXTERNAL payload attached could also present a controllability problem and thus is considered a Safety of Flight issue as well. The aircraft MAY NOT be flown at any time with only one of the two external payloads attached. - Question: Is there any restriction
on the wall thickness of the PVC tube (schedule 40 or schedule 80)?
Answer: No. Since the total payload unit must weight is specified, it does not matter what portion of the payload weight comes from the PVC tube versus what is ballast added to meet the minimum weight. - Question: The contest rules state
that the payload must be symmetric to the fuselage centerline. Does this
rule-out putting payloads inline? ie; end to end
internal to the fuselage?
Answer: Yes. You may not have the internal payloads stored one in front of the other. - Question: Is the PVC we have to
use for the payloads 3" ID or 3"OD?
Answer: See #6 - Question: The rules state that the
payload need to be carried on hard points located within 3" of the
wing tips. Does this mean that the centerline of the payload has to be
within 3" of the wing tip, or the outermost edge of the payload has
to be within 3" of the wing tip?
Answer: The payload centerline must be within 3” of the wing tip. - Question: PVC Pipe for Payload
Questions
Answer: Several teams have contacted me about finding many more variations of “3 inch PVC” pipe than I knew existed. To simplify, any PVC pipe of greater than 3” inside diameter will be allowed for the payloads. Teams should have the payload ends removable so the judges can verify the inside diameter only if the outside diameter of their pipe is less than 3 ¼” (which will be assumed sufficient for a 3” inside diameter). - Question: Can we drill holes in
the PVC pipe to allow installing the release mechanism latches?
Answer: Yes, you may drill holes in the PVC to attach components as required. The Release mechanism must attach to a fitting “external” to the tube profile, it can not reach “inside” the tube to connect to it. - Question: Can the release
mechanism be inside the PVC payload and be controlled by a separate RC
system?
Answer: No. The release system must be a part of the aircraft, not the payload. Also see QA #7 above. - Question: Is it legal to carry the
payloads with their axis perpendicular to the fuselage axis?
Answer: Yes, as long as the payload is carried in the “fuselage” and not in the wing, and they still retain the “side-by-side” symmetry, placing one ahead of the other is not allowed (see #3 above). - Question: For the Re-supply
mission, can we unload/reload the payloads by means of a box-type case? Or
must we unload/reload one payload at a time by hand?
Answer: You may have a module that contains both payloads. The payload(s) weight will be measured when removed from the module.
Flight /
- Question:
Do we have to fly two
different missions to get a score?
Answer: No. If you choose or are unable to fly more than 1 mission you will still get a score for that mission. - Question: What would constitute “non-critical”
versus “significant damage” on landing as described in the rules?
Answer: The decision will be at the discretion of the flight line judges. In general, “non-critical” damage would allow the aircraft to be easily returned to safe flight status. A couple of examples of “non-critical” damage would be a broken propeller, bent landing gear, sheared nylon bolts or minor scratches to the finish. If any component is structurally damaged and would be considered a hazard to safe flight then it will be considered as “significant damage”. - Questions:
Does the ten minute
mission window apply to one flight attempt (chosen from Mission A, B or C)
or to two different Missions flown in one uninterrupted sequence?
Answer: The 10 minute window is for a single mission event (A, B or C). - Question: In the
rules examples, all the times are in round minutes. What accuracy will be used for
determining flight times?
Answer: It’s just to make the rules document cases simple. We will record times to the accuracy possible, probably to nearest second. - 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. - 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. - 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. - Question: Can we tailor the configuration
of the aircraft differently for the different missions? For example, could we use different
sized propulsion systems for each flight?
Answer: You cannot change the hardware configuration of the aircraft for the different missions. You could however run only 1 motor of a two motor aircraft for a no payload lap/flight, and run both motors for a with payload lap/flight, provided both motors and propellers are installed for all flights. You can however change the propeller diameter/pitch for each flight attempt. - Question: Can you provide a sketch of the
locations of the drop zones for the sensor reposition mission?
Answer: The information provided in the rules section should be sufficient for design purposes, the exact locations will be a function of the runway in use and may differ somewhat if we change runways due to wind direction.
The first release/pickup area will be after the take-off “start line” so the aircraft will have completed a full lap prior to the first release. The first release will be near the opposite side of the runway from the observers and aircraft staging. The second will be near the runway centerline to allow an easier transition for take-off. Both locations will be close enough to the start line and nominal pilot/crew locations to provide good pilot visibility and far enough apart to require good aircraft ground handling. - Question: Must the
aircraft come to a complete stop before releasing the sensor-deployment
payload(s)?
Answer: Yes - Question: In the
sensor reposition mission disassembly, can we release the tip payloads
using the RC system, and the payloads be stored “off” the airframe?
Answer: Yes, the payloads may be stored “in the box” either attached to the wing tips or removed. If removed, they may be released either using the RC system (it is on a separate battery from the motor, the motor battery must be disconnected by removing the arming fuse before ANY work on disassembly begins) or manually.
Report Questions
- Question:
For the “Testing Plan” section of the report in-flight tests are
required. Is there a point penalty
for not completing the in-flight tests?
Answer: To obtain the maximum points all information asked for in a section must be present. Point deductions will be determined by the judges based on provided-vs-missing information. - Question:
In the RAC is “motor controller” the same as “speed controller”.
Answer: Yes, the two terms could be taken interchangeably. - Question:
In the RAC do electric brakes count as a type of controller
Answer: Yes. A single servo or solenoid controlling air or hydraulic brakes would count as one controller. If a separate electric actuators are used for each wheel, that would count as two (or more) controllers - Question:
The RAC states: "A "V" tail is considered to be a Vertical
surface without control (5 hr) plus a horizontal surface with controls (10
hr), for a total of 15 hrs"
.How is the horizontal span of the V-tail applied under the
provision that: "A horizontal surface is a 'wing' if it is more than
25% of the span of the greatest span horizontal surface."?
Answer: For the “25% span” rule the horizontal projection of a V-tail will be used as the effective horizontal span. - Question:
Could you please define "control volumes" as stated in the
Rules, Design Report section, paragraph 5
Answer: These are the classic static control volumes, (Surface_area x Lever Arm)/Reference_length - Question: How will the maximum exposed wing chord
would be measured for a flying wing.
For payload considerations, it is stated that the
"fuselage" is the inner most 9" of semi-span. Does this also apply for the maximum
exposed chord measurement, or will the max chord be measured at the
centerline (if this is the largest chord length).
Answer: For “All Wing” configurations the maximum wing chord will be measured 9” out from the centerline or at the largest chord location that is MORE than 9” out from the centerline. - Question:
How will the maximum chord length (root) for a delta wing with varying
leading sweep be calculated to be used in RAC calculation?
Answer: The same as outlined for a flying wing in the question above. - Question:
How is the RAC computed for configurations with multiple fuselages?
Answer: The “width” in the RAC formula would be the width of the multiple fuselages if placed side by side, ie it would not include the span of the wing between the fuselages. - Question:
In the RAC, do we include the tail while writing the maximum length,
height and width of the fuselage
Answer: As stated in the rules, the length of the vertical tail would be included in the fuselage length if it extends aft of the fuselage. The height of the vertical tail is not included.
General Questions
- 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. - 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. - 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. - 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. - 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. - 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. - 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. - 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. - 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). - 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. - 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. - 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. - 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. - 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. - 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). - 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. - 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. - 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. - Question: Do the
wires and connectors have to be commercially available?
Answer: Yes - 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. - Question: Will the
payload be supplied by the team or the contest administration?
Answer: By the team. - 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 facilities and 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. - 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. - Question: Would we
ever have to make any vertical loops with the UAV?
Answer: No - Question: Does the
1/3 under classmen rule apply to the people present at the fly-off site?
Answer: No. The 1/3 , 2/3 distribution applies to the team as a whole, from the entry date through the end of the contest. Not all team members must be present at the fly-off.
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